diff options
Diffstat (limited to 'kernel/bpf')
-rw-r--r-- | kernel/bpf/Makefile | 2 | ||||
-rw-r--r-- | kernel/bpf/arraymap.c | 49 | ||||
-rw-r--r-- | kernel/bpf/cgroup.c | 15 | ||||
-rw-r--r-- | kernel/bpf/core.c | 441 | ||||
-rw-r--r-- | kernel/bpf/cpumap.c | 31 | ||||
-rw-r--r-- | kernel/bpf/devmap.c | 8 | ||||
-rw-r--r-- | kernel/bpf/disasm.c | 63 | ||||
-rw-r--r-- | kernel/bpf/disasm.h | 29 | ||||
-rw-r--r-- | kernel/bpf/hashtab.c | 103 | ||||
-rw-r--r-- | kernel/bpf/inode.c | 50 | ||||
-rw-r--r-- | kernel/bpf/lpm_trie.c | 98 | ||||
-rw-r--r-- | kernel/bpf/offload.c | 430 | ||||
-rw-r--r-- | kernel/bpf/sockmap.c | 197 | ||||
-rw-r--r-- | kernel/bpf/stackmap.c | 34 | ||||
-rw-r--r-- | kernel/bpf/syscall.c | 214 | ||||
-rw-r--r-- | kernel/bpf/verifier.c | 1451 |
16 files changed, 2517 insertions, 698 deletions
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index e691da0b3bab..a713fd23ec88 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -9,9 +9,11 @@ obj-$(CONFIG_BPF_SYSCALL) += devmap.o obj-$(CONFIG_BPF_SYSCALL) += cpumap.o obj-$(CONFIG_BPF_SYSCALL) += offload.o ifeq ($(CONFIG_STREAM_PARSER),y) +ifeq ($(CONFIG_INET),y) obj-$(CONFIG_BPF_SYSCALL) += sockmap.o endif endif +endif ifeq ($(CONFIG_PERF_EVENTS),y) obj-$(CONFIG_BPF_SYSCALL) += stackmap.o endif diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index ab94d304a634..b1f66480135b 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -49,27 +49,35 @@ static int bpf_array_alloc_percpu(struct bpf_array *array) } /* Called from syscall */ -static struct bpf_map *array_map_alloc(union bpf_attr *attr) +static int array_map_alloc_check(union bpf_attr *attr) { bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY; int numa_node = bpf_map_attr_numa_node(attr); - u32 elem_size, index_mask, max_entries; - bool unpriv = !capable(CAP_SYS_ADMIN); - struct bpf_array *array; - u64 array_size, mask64; /* check sanity of attributes */ if (attr->max_entries == 0 || attr->key_size != 4 || attr->value_size == 0 || attr->map_flags & ~ARRAY_CREATE_FLAG_MASK || (percpu && numa_node != NUMA_NO_NODE)) - return ERR_PTR(-EINVAL); + return -EINVAL; if (attr->value_size > KMALLOC_MAX_SIZE) /* if value_size is bigger, the user space won't be able to * access the elements. */ - return ERR_PTR(-E2BIG); + return -E2BIG; + + return 0; +} + +static struct bpf_map *array_map_alloc(union bpf_attr *attr) +{ + bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY; + int numa_node = bpf_map_attr_numa_node(attr); + u32 elem_size, index_mask, max_entries; + bool unpriv = !capable(CAP_SYS_ADMIN); + struct bpf_array *array; + u64 array_size, mask64; elem_size = round_up(attr->value_size, 8); @@ -112,12 +120,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr) array->map.unpriv_array = unpriv; /* copy mandatory map attributes */ - array->map.map_type = attr->map_type; - array->map.key_size = attr->key_size; - array->map.value_size = attr->value_size; - array->map.max_entries = attr->max_entries; - array->map.map_flags = attr->map_flags; - array->map.numa_node = numa_node; + bpf_map_init_from_attr(&array->map, attr); array->elem_size = elem_size; if (!percpu) @@ -327,6 +330,7 @@ static void array_map_free(struct bpf_map *map) } const struct bpf_map_ops array_map_ops = { + .map_alloc_check = array_map_alloc_check, .map_alloc = array_map_alloc, .map_free = array_map_free, .map_get_next_key = array_map_get_next_key, @@ -337,6 +341,7 @@ const struct bpf_map_ops array_map_ops = { }; const struct bpf_map_ops percpu_array_map_ops = { + .map_alloc_check = array_map_alloc_check, .map_alloc = array_map_alloc, .map_free = array_map_free, .map_get_next_key = array_map_get_next_key, @@ -345,12 +350,12 @@ const struct bpf_map_ops percpu_array_map_ops = { .map_delete_elem = array_map_delete_elem, }; -static struct bpf_map *fd_array_map_alloc(union bpf_attr *attr) +static int fd_array_map_alloc_check(union bpf_attr *attr) { /* only file descriptors can be stored in this type of map */ if (attr->value_size != sizeof(u32)) - return ERR_PTR(-EINVAL); - return array_map_alloc(attr); + return -EINVAL; + return array_map_alloc_check(attr); } static void fd_array_map_free(struct bpf_map *map) @@ -474,7 +479,8 @@ void bpf_fd_array_map_clear(struct bpf_map *map) } const struct bpf_map_ops prog_array_map_ops = { - .map_alloc = fd_array_map_alloc, + .map_alloc_check = fd_array_map_alloc_check, + .map_alloc = array_map_alloc, .map_free = fd_array_map_free, .map_get_next_key = array_map_get_next_key, .map_lookup_elem = fd_array_map_lookup_elem, @@ -561,7 +567,8 @@ static void perf_event_fd_array_release(struct bpf_map *map, } const struct bpf_map_ops perf_event_array_map_ops = { - .map_alloc = fd_array_map_alloc, + .map_alloc_check = fd_array_map_alloc_check, + .map_alloc = array_map_alloc, .map_free = fd_array_map_free, .map_get_next_key = array_map_get_next_key, .map_lookup_elem = fd_array_map_lookup_elem, @@ -592,7 +599,8 @@ static void cgroup_fd_array_free(struct bpf_map *map) } const struct bpf_map_ops cgroup_array_map_ops = { - .map_alloc = fd_array_map_alloc, + .map_alloc_check = fd_array_map_alloc_check, + .map_alloc = array_map_alloc, .map_free = cgroup_fd_array_free, .map_get_next_key = array_map_get_next_key, .map_lookup_elem = fd_array_map_lookup_elem, @@ -610,7 +618,7 @@ static struct bpf_map *array_of_map_alloc(union bpf_attr *attr) if (IS_ERR(inner_map_meta)) return inner_map_meta; - map = fd_array_map_alloc(attr); + map = array_map_alloc(attr); if (IS_ERR(map)) { bpf_map_meta_free(inner_map_meta); return map; @@ -673,6 +681,7 @@ static u32 array_of_map_gen_lookup(struct bpf_map *map, } const struct bpf_map_ops array_of_maps_map_ops = { + .map_alloc_check = fd_array_map_alloc_check, .map_alloc = array_of_map_alloc, .map_free = array_of_map_free, .map_get_next_key = array_map_get_next_key, diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index b789ab78d28f..c1c0b60d3f2f 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -568,6 +568,8 @@ static bool cgroup_dev_is_valid_access(int off, int size, enum bpf_access_type type, struct bpf_insn_access_aux *info) { + const int size_default = sizeof(__u32); + if (type == BPF_WRITE) return false; @@ -576,8 +578,17 @@ static bool cgroup_dev_is_valid_access(int off, int size, /* The verifier guarantees that size > 0. */ if (off % size != 0) return false; - if (size != sizeof(__u32)) - return false; + + switch (off) { + case bpf_ctx_range(struct bpf_cgroup_dev_ctx, access_type): + bpf_ctx_record_field_size(info, size_default); + if (!bpf_ctx_narrow_access_ok(off, size, size_default)) + return false; + break; + default: + if (size != size_default) + return false; + } return true; } diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 7949e8b8f94e..29ca9208dcfa 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -94,6 +94,7 @@ struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) fp->pages = size / PAGE_SIZE; fp->aux = aux; fp->aux->prog = fp; + fp->jit_requested = ebpf_jit_enabled(); INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode); @@ -217,30 +218,40 @@ int bpf_prog_calc_tag(struct bpf_prog *fp) return 0; } -static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn) -{ - return BPF_CLASS(insn->code) == BPF_JMP && - /* Call and Exit are both special jumps with no - * target inside the BPF instruction image. - */ - BPF_OP(insn->code) != BPF_CALL && - BPF_OP(insn->code) != BPF_EXIT; -} - static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta) { struct bpf_insn *insn = prog->insnsi; u32 i, insn_cnt = prog->len; + bool pseudo_call; + u8 code; + int off; for (i = 0; i < insn_cnt; i++, insn++) { - if (!bpf_is_jmp_and_has_target(insn)) + code = insn->code; + if (BPF_CLASS(code) != BPF_JMP) continue; + if (BPF_OP(code) == BPF_EXIT) + continue; + if (BPF_OP(code) == BPF_CALL) { + if (insn->src_reg == BPF_PSEUDO_CALL) + pseudo_call = true; + else + continue; + } else { + pseudo_call = false; + } + off = pseudo_call ? insn->imm : insn->off; /* Adjust offset of jmps if we cross boundaries. */ - if (i < pos && i + insn->off + 1 > pos) - insn->off += delta; - else if (i > pos + delta && i + insn->off + 1 <= pos + delta) - insn->off -= delta; + if (i < pos && i + off + 1 > pos) + off += delta; + else if (i > pos + delta && i + off + 1 <= pos + delta) + off -= delta; + + if (pseudo_call) + insn->imm = off; + else + insn->off = off; } } @@ -289,6 +300,11 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, } #ifdef CONFIG_BPF_JIT +/* All BPF JIT sysctl knobs here. */ +int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON); +int bpf_jit_harden __read_mostly; +int bpf_jit_kallsyms __read_mostly; + static __always_inline void bpf_get_prog_addr_region(const struct bpf_prog *prog, unsigned long *symbol_start, @@ -370,8 +386,6 @@ static DEFINE_SPINLOCK(bpf_lock); static LIST_HEAD(bpf_kallsyms); static struct latch_tree_root bpf_tree __cacheline_aligned; -int bpf_jit_kallsyms __read_mostly; - static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux) { WARN_ON_ONCE(!list_empty(&aux->ksym_lnode)); @@ -552,8 +566,6 @@ void __weak bpf_jit_free(struct bpf_prog *fp) bpf_prog_unlock_free(fp); } -int bpf_jit_harden __read_mostly; - static int bpf_jit_blind_insn(const struct bpf_insn *from, const struct bpf_insn *aux, struct bpf_insn *to_buff) @@ -711,7 +723,7 @@ struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) struct bpf_insn *insn; int i, rewritten; - if (!bpf_jit_blinding_enabled()) + if (!bpf_jit_blinding_enabled(prog) || prog->blinded) return prog; clone = bpf_prog_clone_create(prog, GFP_USER); @@ -753,13 +765,16 @@ struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) i += insn_delta; } + clone->blinded = 1; return clone; } #endif /* CONFIG_BPF_JIT */ /* Base function for offset calculation. Needs to go into .text section, * therefore keeping it non-static as well; will also be used by JITs - * anyway later on, so do not let the compiler omit it. + * anyway later on, so do not let the compiler omit it. This also needs + * to go into kallsyms for correlation from e.g. bpftool, so naming + * must not change. */ noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { @@ -767,6 +782,137 @@ noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) } EXPORT_SYMBOL_GPL(__bpf_call_base); +/* All UAPI available opcodes. */ +#define BPF_INSN_MAP(INSN_2, INSN_3) \ + /* 32 bit ALU operations. */ \ + /* Register based. */ \ + INSN_3(ALU, ADD, X), \ + INSN_3(ALU, SUB, X), \ + INSN_3(ALU, AND, X), \ + INSN_3(ALU, OR, X), \ + INSN_3(ALU, LSH, X), \ + INSN_3(ALU, RSH, X), \ + INSN_3(ALU, XOR, X), \ + INSN_3(ALU, MUL, X), \ + INSN_3(ALU, MOV, X), \ + INSN_3(ALU, DIV, X), \ + INSN_3(ALU, MOD, X), \ + INSN_2(ALU, NEG), \ + INSN_3(ALU, END, TO_BE), \ + INSN_3(ALU, END, TO_LE), \ + /* Immediate based. */ \ + INSN_3(ALU, ADD, K), \ + INSN_3(ALU, SUB, K), \ + INSN_3(ALU, AND, K), \ + INSN_3(ALU, OR, K), \ + INSN_3(ALU, LSH, K), \ + INSN_3(ALU, RSH, K), \ + INSN_3(ALU, XOR, K), \ + INSN_3(ALU, MUL, K), \ + INSN_3(ALU, MOV, K), \ + INSN_3(ALU, DIV, K), \ + INSN_3(ALU, MOD, K), \ + /* 64 bit ALU operations. */ \ + /* Register based. */ \ + INSN_3(ALU64, ADD, X), \ + INSN_3(ALU64, SUB, X), \ + INSN_3(ALU64, AND, X), \ + INSN_3(ALU64, OR, X), \ + INSN_3(ALU64, LSH, X), \ + INSN_3(ALU64, RSH, X), \ + INSN_3(ALU64, XOR, X), \ + INSN_3(ALU64, MUL, X), \ + INSN_3(ALU64, MOV, X), \ + INSN_3(ALU64, ARSH, X), \ + INSN_3(ALU64, DIV, X), \ + INSN_3(ALU64, MOD, X), \ + INSN_2(ALU64, NEG), \ + /* Immediate based. */ \ + INSN_3(ALU64, ADD, K), \ + INSN_3(ALU64, SUB, K), \ + INSN_3(ALU64, AND, K), \ + INSN_3(ALU64, OR, K), \ + INSN_3(ALU64, LSH, K), \ + INSN_3(ALU64, RSH, K), \ + INSN_3(ALU64, XOR, K), \ + INSN_3(ALU64, MUL, K), \ + INSN_3(ALU64, MOV, K), \ + INSN_3(ALU64, ARSH, K), \ + INSN_3(ALU64, DIV, K), \ + INSN_3(ALU64, MOD, K), \ + /* Call instruction. */ \ + INSN_2(JMP, CALL), \ + /* Exit instruction. */ \ + INSN_2(JMP, EXIT), \ + /* Jump instructions. */ \ + /* Register based. */ \ + INSN_3(JMP, JEQ, X), \ + INSN_3(JMP, JNE, X), \ + INSN_3(JMP, JGT, X), \ + INSN_3(JMP, JLT, X), \ + INSN_3(JMP, JGE, X), \ + INSN_3(JMP, JLE, X), \ + INSN_3(JMP, JSGT, X), \ + INSN_3(JMP, JSLT, X), \ + INSN_3(JMP, JSGE, X), \ + INSN_3(JMP, JSLE, X), \ + INSN_3(JMP, JSET, X), \ + /* Immediate based. */ \ + INSN_3(JMP, JEQ, K), \ + INSN_3(JMP, JNE, K), \ + INSN_3(JMP, JGT, K), \ + INSN_3(JMP, JLT, K), \ + INSN_3(JMP, JGE, K), \ + INSN_3(JMP, JLE, K), \ + INSN_3(JMP, JSGT, K), \ + INSN_3(JMP, JSLT, K), \ + INSN_3(JMP, JSGE, K), \ + INSN_3(JMP, JSLE, K), \ + INSN_3(JMP, JSET, K), \ + INSN_2(JMP, JA), \ + /* Store instructions. */ \ + /* Register based. */ \ + INSN_3(STX, MEM, B), \ + INSN_3(STX, MEM, H), \ + INSN_3(STX, MEM, W), \ + INSN_3(STX, MEM, DW), \ + INSN_3(STX, XADD, W), \ + INSN_3(STX, XADD, DW), \ + /* Immediate based. */ \ + INSN_3(ST, MEM, B), \ + INSN_3(ST, MEM, H), \ + INSN_3(ST, MEM, W), \ + INSN_3(ST, MEM, DW), \ + /* Load instructions. */ \ + /* Register based. */ \ + INSN_3(LDX, MEM, B), \ + INSN_3(LDX, MEM, H), \ + INSN_3(LDX, MEM, W), \ + INSN_3(LDX, MEM, DW), \ + /* Immediate based. */ \ + INSN_3(LD, IMM, DW), \ + /* Misc (old cBPF carry-over). */ \ + INSN_3(LD, ABS, B), \ + INSN_3(LD, ABS, H), \ + INSN_3(LD, ABS, W), \ + INSN_3(LD, IND, B), \ + INSN_3(LD, IND, H), \ + INSN_3(LD, IND, W) + +bool bpf_opcode_in_insntable(u8 code) +{ +#define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true +#define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true + static const bool public_insntable[256] = { + [0 ... 255] = false, + /* Now overwrite non-defaults ... */ + BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), + }; +#undef BPF_INSN_3_TBL +#undef BPF_INSN_2_TBL + return public_insntable[code]; +} + #ifndef CONFIG_BPF_JIT_ALWAYS_ON /** * __bpf_prog_run - run eBPF program on a given context @@ -775,118 +921,21 @@ EXPORT_SYMBOL_GPL(__bpf_call_base); * * Decode and execute eBPF instructions. */ -static unsigned int ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, - u64 *stack) +static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) { u64 tmp; +#define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y +#define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z static const void *jumptable[256] = { [0 ... 255] = &&default_label, /* Now overwrite non-defaults ... */ - /* 32 bit ALU operations */ - [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X, - [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K, - [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X, - [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K, - [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X, - [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K, - [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X, - [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K, - [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X, - [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K, - [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X, - [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K, - [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X, - [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K, - [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X, - [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K, - [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X, - [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K, - [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X, - [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K, - [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X, - [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K, - [BPF_ALU | BPF_NEG] = &&ALU_NEG, - [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE, - [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE, - /* 64 bit ALU operations */ - [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X, - [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K, - [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X, - [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K, - [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X, - [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K, - [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X, - [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K, - [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X, - [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K, - [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X, - [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K, - [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X, - [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K, - [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X, - [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K, - [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X, - [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K, - [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X, - [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K, - [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X, - [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K, - [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X, - [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K, - [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG, - /* Call instruction */ - [BPF_JMP | BPF_CALL] = &&JMP_CALL, + BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), + /* Non-UAPI available opcodes. */ + [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, - /* Jumps */ - [BPF_JMP | BPF_JA] = &&JMP_JA, - [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X, - [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K, - [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X, - [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K, - [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X, - [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K, - [BPF_JMP | BPF_JLT | BPF_X] = &&JMP_JLT_X, - [BPF_JMP | BPF_JLT | BPF_K] = &&JMP_JLT_K, - [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X, - [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K, - [BPF_JMP | BPF_JLE | BPF_X] = &&JMP_JLE_X, - [BPF_JMP | BPF_JLE | BPF_K] = &&JMP_JLE_K, - [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X, - [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K, - [BPF_JMP | BPF_JSLT | BPF_X] = &&JMP_JSLT_X, - [BPF_JMP | BPF_JSLT | BPF_K] = &&JMP_JSLT_K, - [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X, - [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K, - [BPF_JMP | BPF_JSLE | BPF_X] = &&JMP_JSLE_X, - [BPF_JMP | BPF_JSLE | BPF_K] = &&JMP_JSLE_K, - [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X, - [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K, - /* Program return */ - [BPF_JMP | BPF_EXIT] = &&JMP_EXIT, - /* Store instructions */ - [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B, - [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H, - [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W, - [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW, - [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W, - [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW, - [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B, - [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H, - [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W, - [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW, - /* Load instructions */ - [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B, - [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H, - [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W, - [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW, - [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W, - [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H, - [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B, - [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W, - [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H, - [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B, - [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW, }; +#undef BPF_INSN_3_LBL +#undef BPF_INSN_2_LBL u32 tail_call_cnt = 0; void *ptr; int off; @@ -950,14 +999,10 @@ select_insn: (*(s64 *) &DST) >>= IMM; CONT; ALU64_MOD_X: - if (unlikely(SRC == 0)) - return 0; div64_u64_rem(DST, SRC, &tmp); DST = tmp; CONT; ALU_MOD_X: - if (unlikely((u32)SRC == 0)) - return 0; tmp = (u32) DST; DST = do_div(tmp, (u32) SRC); CONT; @@ -970,13 +1015,9 @@ select_insn: DST = do_div(tmp, (u32) IMM); CONT; ALU64_DIV_X: - if (unlikely(SRC == 0)) - return 0; DST = div64_u64(DST, SRC); CONT; ALU_DIV_X: - if (unlikely((u32)SRC == 0)) - return 0; tmp = (u32) DST; do_div(tmp, (u32) SRC); DST = (u32) tmp; @@ -1026,6 +1067,13 @@ select_insn: BPF_R4, BPF_R5); CONT; + JMP_CALL_ARGS: + BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, + BPF_R3, BPF_R4, + BPF_R5, + insn + insn->off + 1); + CONT; + JMP_TAIL_CALL: { struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; struct bpf_array *array = container_of(map, struct bpf_array, map); @@ -1280,8 +1328,14 @@ load_byte: goto load_byte; default_label: - /* If we ever reach this, we have a bug somewhere. */ - WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code); + /* If we ever reach this, we have a bug somewhere. Die hard here + * instead of just returning 0; we could be somewhere in a subprog, + * so execution could continue otherwise which we do /not/ want. + * + * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). + */ + pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code); + BUG_ON(1); return 0; } STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */ @@ -1298,6 +1352,23 @@ static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn return ___bpf_prog_run(regs, insn, stack); \ } +#define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size +#define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ +static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ + const struct bpf_insn *insn) \ +{ \ + u64 stack[stack_size / sizeof(u64)]; \ + u64 regs[MAX_BPF_REG]; \ +\ + FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ + BPF_R1 = r1; \ + BPF_R2 = r2; \ + BPF_R3 = r3; \ + BPF_R4 = r4; \ + BPF_R5 = r5; \ + return ___bpf_prog_run(regs, insn, stack); \ +} + #define EVAL1(FN, X) FN(X) #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) @@ -1309,6 +1380,10 @@ EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); +EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); +EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); +EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); + #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), static unsigned int (*interpreters[])(const void *ctx, @@ -1317,11 +1392,33 @@ EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) }; +#undef PROG_NAME_LIST +#define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), +static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, + const struct bpf_insn *insn) = { +EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) +EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) +EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) +}; +#undef PROG_NAME_LIST + +void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) +{ + stack_depth = max_t(u32, stack_depth, 1); + insn->off = (s16) insn->imm; + insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - + __bpf_call_base_args; + insn->code = BPF_JMP | BPF_CALL_ARGS; +} #else -static unsigned int __bpf_prog_ret0(const void *ctx, - const struct bpf_insn *insn) +static unsigned int __bpf_prog_ret0_warn(const void *ctx, + const struct bpf_insn *insn) { + /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON + * is not working properly, so warn about it! + */ + WARN_ON_ONCE(1); return 0; } #endif @@ -1329,6 +1426,9 @@ static unsigned int __bpf_prog_ret0(const void *ctx, bool bpf_prog_array_compatible(struct bpf_array *array, const struct bpf_prog *fp) { + if (fp->kprobe_override) + return false; + if (!array->owner_prog_type) { /* There's no owner yet where we could check for * compatibility. @@ -1378,7 +1478,7 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; #else - fp->bpf_func = __bpf_prog_ret0; + fp->bpf_func = __bpf_prog_ret0_warn; #endif /* eBPF JITs can rewrite the program in case constant @@ -1476,23 +1576,41 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, __u32 __user *prog_ids, u32 cnt) { struct bpf_prog **prog; - u32 i = 0, id; - + unsigned long err = 0; + u32 i = 0, *ids; + bool nospc; + + /* users of this function are doing: + * cnt = bpf_prog_array_length(); + * if (cnt > 0) + * bpf_prog_array_copy_to_user(..., cnt); + * so below kcalloc doesn't need extra cnt > 0 check, but + * bpf_prog_array_length() releases rcu lock and + * prog array could have been swapped with empty or larger array, + * so always copy 'cnt' prog_ids to the user. + * In a rare race the user will see zero prog_ids + */ + ids = kcalloc(cnt, sizeof(u32), GFP_USER); + if (!ids) + return -ENOMEM; rcu_read_lock(); prog = rcu_dereference(progs)->progs; for (; *prog; prog++) { - id = (*prog)->aux->id; - if (copy_to_user(prog_ids + i, &id, sizeof(id))) { - rcu_read_unlock(); - return -EFAULT; - } + if (*prog == &dummy_bpf_prog.prog) + continue; + ids[i] = (*prog)->aux->id; if (++i == cnt) { prog++; break; } } + nospc = !!(*prog); rcu_read_unlock(); - if (*prog) + err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); + kfree(ids); + if (err) + return -EFAULT; + if (nospc) return -ENOSPC; return 0; } @@ -1564,14 +1682,41 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, return 0; } +int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, + __u32 __user *prog_ids, u32 request_cnt, + __u32 __user *prog_cnt) +{ + u32 cnt = 0; + + if (array) + cnt = bpf_prog_array_length(array); + + if (copy_to_user(prog_cnt, &cnt, sizeof(cnt))) + return -EFAULT; + + /* return early if user requested only program count or nothing to copy */ + if (!request_cnt || !cnt) + return 0; + + return bpf_prog_array_copy_to_user(array, prog_ids, request_cnt); +} + static void bpf_prog_free_deferred(struct work_struct *work) { struct bpf_prog_aux *aux; + int i; aux = container_of(work, struct bpf_prog_aux, work); if (bpf_prog_is_dev_bound(aux)) bpf_prog_offload_destroy(aux->prog); - bpf_jit_free(aux->prog); + for (i = 0; i < aux->func_cnt; i++) + bpf_jit_free(aux->func[i]); + if (aux->func_cnt) { + kfree(aux->func); + bpf_prog_unlock_free(aux->prog); + } else { + bpf_jit_free(aux->prog); + } } /* Free internal BPF program */ diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index ce5b669003b2..fbfdada6caee 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -94,13 +94,7 @@ static struct bpf_map *cpu_map_alloc(union bpf_attr *attr) if (!cmap) return ERR_PTR(-ENOMEM); - /* mandatory map attributes */ - cmap->map.map_type = attr->map_type; - cmap->map.key_size = attr->key_size; - cmap->map.value_size = attr->value_size; - cmap->map.max_entries = attr->max_entries; - cmap->map.map_flags = attr->map_flags; - cmap->map.numa_node = bpf_map_attr_numa_node(attr); + bpf_map_init_from_attr(&cmap->map, attr); /* Pre-limit array size based on NR_CPUS, not final CPU check */ if (cmap->map.max_entries > NR_CPUS) { @@ -143,7 +137,7 @@ free_cmap: return ERR_PTR(err); } -void __cpu_map_queue_destructor(void *ptr) +static void __cpu_map_queue_destructor(void *ptr) { /* The tear-down procedure should have made sure that queue is * empty. See __cpu_map_entry_replace() and work-queue @@ -222,8 +216,8 @@ static struct xdp_pkt *convert_to_xdp_pkt(struct xdp_buff *xdp) return xdp_pkt; } -struct sk_buff *cpu_map_build_skb(struct bpf_cpu_map_entry *rcpu, - struct xdp_pkt *xdp_pkt) +static struct sk_buff *cpu_map_build_skb(struct bpf_cpu_map_entry *rcpu, + struct xdp_pkt *xdp_pkt) { unsigned int frame_size; void *pkt_data_start; @@ -337,7 +331,8 @@ static int cpu_map_kthread_run(void *data) return 0; } -struct bpf_cpu_map_entry *__cpu_map_entry_alloc(u32 qsize, u32 cpu, int map_id) +static struct bpf_cpu_map_entry *__cpu_map_entry_alloc(u32 qsize, u32 cpu, + int map_id) { gfp_t gfp = GFP_ATOMIC|__GFP_NOWARN; struct bpf_cpu_map_entry *rcpu; @@ -395,7 +390,7 @@ free_rcu: return NULL; } -void __cpu_map_entry_free(struct rcu_head *rcu) +static void __cpu_map_entry_free(struct rcu_head *rcu) { struct bpf_cpu_map_entry *rcpu; int cpu; @@ -438,8 +433,8 @@ void __cpu_map_entry_free(struct rcu_head *rcu) * cpu_map_kthread_stop, which waits for an RCU graze period before * stopping kthread, emptying the queue. */ -void __cpu_map_entry_replace(struct bpf_cpu_map *cmap, - u32 key_cpu, struct bpf_cpu_map_entry *rcpu) +static void __cpu_map_entry_replace(struct bpf_cpu_map *cmap, + u32 key_cpu, struct bpf_cpu_map_entry *rcpu) { struct bpf_cpu_map_entry *old_rcpu; @@ -451,7 +446,7 @@ void __cpu_map_entry_replace(struct bpf_cpu_map *cmap, } } -int cpu_map_delete_elem(struct bpf_map *map, void *key) +static int cpu_map_delete_elem(struct bpf_map *map, void *key) { struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); u32 key_cpu = *(u32 *)key; @@ -464,8 +459,8 @@ int cpu_map_delete_elem(struct bpf_map *map, void *key) return 0; } -int cpu_map_update_elem(struct bpf_map *map, void *key, void *value, - u64 map_flags) +static int cpu_map_update_elem(struct bpf_map *map, void *key, void *value, + u64 map_flags) { struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); struct bpf_cpu_map_entry *rcpu; @@ -502,7 +497,7 @@ int cpu_map_update_elem(struct bpf_map *map, void *key, void *value, return 0; } -void cpu_map_free(struct bpf_map *map) +static void cpu_map_free(struct bpf_map *map) { struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map); int cpu; diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index ebdef54bf7df..565f9ece9115 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -93,13 +93,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) if (!dtab) return ERR_PTR(-ENOMEM); - /* mandatory map attributes */ - dtab->map.map_type = attr->map_type; - dtab->map.key_size = attr->key_size; - dtab->map.value_size = attr->value_size; - dtab->map.max_entries = attr->max_entries; - dtab->map.map_flags = attr->map_flags; - dtab->map.numa_node = bpf_map_attr_numa_node(attr); + bpf_map_init_from_attr(&dtab->map, attr); /* make sure page count doesn't overflow */ cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *); diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c index e682850c9715..8740406df2cd 100644 --- a/kernel/bpf/disasm.c +++ b/kernel/bpf/disasm.c @@ -21,10 +21,39 @@ static const char * const func_id_str[] = { }; #undef __BPF_FUNC_STR_FN -const char *func_id_name(int id) +static const char *__func_get_name(const struct bpf_insn_cbs *cbs, + const struct bpf_insn *insn, + char *buff, size_t len) { BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID); + if (insn->src_reg != BPF_PSEUDO_CALL && + insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID && + func_id_str[insn->imm]) + return func_id_str[insn->imm]; + + if (cbs && cbs->cb_call) + return cbs->cb_call(cbs->private_data, insn); + + if (insn->src_reg == BPF_PSEUDO_CALL) + snprintf(buff, len, "%+d", insn->imm); + + return buff; +} + +static const char *__func_imm_name(const struct bpf_insn_cbs *cbs, + const struct bpf_insn *insn, + u64 full_imm, char *buff, size_t len) +{ + if (cbs && cbs->cb_imm) + return cbs->cb_imm(cbs->private_data, insn, full_imm); + + snprintf(buff, len, "0x%llx", (unsigned long long)full_imm); + return buff; +} + +const char *func_id_name(int id) +{ if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id]) return func_id_str[id]; else @@ -83,7 +112,7 @@ static const char *const bpf_jmp_string[16] = { [BPF_EXIT >> 4] = "exit", }; -static void print_bpf_end_insn(bpf_insn_print_cb verbose, +static void print_bpf_end_insn(bpf_insn_print_t verbose, struct bpf_verifier_env *env, const struct bpf_insn *insn) { @@ -92,9 +121,12 @@ static void print_bpf_end_insn(bpf_insn_print_cb verbose, insn->imm, insn->dst_reg); } -void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env, - const struct bpf_insn *insn, bool allow_ptr_leaks) +void print_bpf_insn(const struct bpf_insn_cbs *cbs, + struct bpf_verifier_env *env, + const struct bpf_insn *insn, + bool allow_ptr_leaks) { + const bpf_insn_print_t verbose = cbs->cb_print; u8 class = BPF_CLASS(insn->code); if (class == BPF_ALU || class == BPF_ALU64) { @@ -175,12 +207,15 @@ void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env, */ u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; bool map_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD; + char tmp[64]; if (map_ptr && !allow_ptr_leaks) imm = 0; - verbose(env, "(%02x) r%d = 0x%llx\n", insn->code, - insn->dst_reg, (unsigned long long)imm); + verbose(env, "(%02x) r%d = %s\n", + insn->code, insn->dst_reg, + __func_imm_name(cbs, insn, imm, + tmp, sizeof(tmp))); } else { verbose(env, "BUG_ld_%02x\n", insn->code); return; @@ -189,8 +224,20 @@ void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env, u8 opcode = BPF_OP(insn->code); if (opcode == BPF_CALL) { - verbose(env, "(%02x) call %s#%d\n", insn->code, - func_id_name(insn->imm), insn->imm); + char tmp[64]; + + if (insn->src_reg == BPF_PSEUDO_CALL) { + verbose(env, "(%02x) call pc%s\n", + insn->code, + __func_get_name(cbs, insn, + tmp, sizeof(tmp))); + } else { + strcpy(tmp, "unknown"); + verbose(env, "(%02x) call %s#%d\n", insn->code, + __func_get_name(cbs, insn, + tmp, sizeof(tmp)), + insn->imm); + } } else if (insn->code == (BPF_JMP | BPF_JA)) { verbose(env, "(%02x) goto pc%+d\n", insn->code, insn->off); diff --git a/kernel/bpf/disasm.h b/kernel/bpf/disasm.h index 8de977e420b6..266fe8ee542b 100644 --- a/kernel/bpf/disasm.h +++ b/kernel/bpf/disasm.h @@ -17,16 +17,35 @@ #include <linux/bpf.h> #include <linux/kernel.h> #include <linux/stringify.h> +#ifndef __KERNEL__ +#include <stdio.h> +#include <string.h> +#endif + +struct bpf_verifier_env; extern const char *const bpf_alu_string[16]; extern const char *const bpf_class_string[8]; const char *func_id_name(int id); -struct bpf_verifier_env; -typedef void (*bpf_insn_print_cb)(struct bpf_verifier_env *env, - const char *, ...); -void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env, - const struct bpf_insn *insn, bool allow_ptr_leaks); +typedef __printf(2, 3) void (*bpf_insn_print_t)(struct bpf_verifier_env *env, + const char *, ...); +typedef const char *(*bpf_insn_revmap_call_t)(void *private_data, + const struct bpf_insn *insn); +typedef const char *(*bpf_insn_print_imm_t)(void *private_data, + const struct bpf_insn *insn, + __u64 full_imm); + +struct bpf_insn_cbs { + bpf_insn_print_t cb_print; + bpf_insn_revmap_call_t cb_call; + bpf_insn_print_imm_t cb_imm; + void *private_data; +}; +void print_bpf_insn(const struct bpf_insn_cbs *cbs, + struct bpf_verifier_env *env, + const struct bpf_insn *insn, + bool allow_ptr_leaks); #endif diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 3905d4bc5b80..b76828f23b49 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -227,7 +227,7 @@ static int alloc_extra_elems(struct bpf_htab *htab) } /* Called from syscall */ -static struct bpf_map *htab_map_alloc(union bpf_attr *attr) +static int htab_map_alloc_check(union bpf_attr *attr) { bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH || attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH); @@ -241,9 +241,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU); bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC); int numa_node = bpf_map_attr_numa_node(attr); - struct bpf_htab *htab; - int err, i; - u64 cost; BUILD_BUG_ON(offsetof(struct htab_elem, htab) != offsetof(struct htab_elem, hash_node.pprev)); @@ -254,40 +251,68 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) /* LRU implementation is much complicated than other * maps. Hence, limit to CAP_SYS_ADMIN for now. */ - return ERR_PTR(-EPERM); + return -EPERM; if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK) /* reserved bits should not be used */ - return ERR_PTR(-EINVAL); + return -EINVAL; if (!lru && percpu_lru) - return ERR_PTR(-EINVAL); + return -EINVAL; if (lru && !prealloc) - return ERR_PTR(-ENOTSUPP); + return -ENOTSUPP; if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru)) - return ERR_PTR(-EINVAL); + return -EINVAL; + + /* check sanity of attributes. + * value_size == 0 may be allowed in the future to use map as a set + */ + if (attr->max_entries == 0 || attr->key_size == 0 || + attr->value_size == 0) + return -EINVAL; + + if (attr->key_size > MAX_BPF_STACK) + /* eBPF programs initialize keys on stack, so they cannot be + * larger than max stack size + */ + return -E2BIG; + + if (attr->value_size >= KMALLOC_MAX_SIZE - + MAX_BPF_STACK - sizeof(struct htab_elem)) + /* if value_size is bigger, the user space won't be able to + * access the elements via bpf syscall. This check also makes + * sure that the elem_size doesn't overflow and it's + * kmalloc-able later in htab_map_update_elem() + */ + return -E2BIG; + + return 0; +} + +static struct bpf_map *htab_map_alloc(union bpf_attr *attr) +{ + bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH || + attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH); + bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH || + attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH); + /* percpu_lru means each cpu has its own LRU list. + * it is different from BPF_MAP_TYPE_PERCPU_HASH where + * the map's value itself is percpu. percpu_lru has + * nothing to do with the map's value. + */ + bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU); + bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC); + struct bpf_htab *htab; + int err, i; + u64 cost; htab = kzalloc(sizeof(*htab), GFP_USER); if (!htab) return ERR_PTR(-ENOMEM); - /* mandatory map attributes */ - htab->map.map_type = attr->map_type; - htab->map.key_size = attr->key_size; - htab->map.value_size = attr->value_size; - htab->map.max_entries = attr->max_entries; - htab->map.map_flags = attr->map_flags; - htab->map.numa_node = numa_node; - - /* check sanity of attributes. - * value_size == 0 may be allowed in the future to use map as a set - */ - err = -EINVAL; - if (htab->map.max_entries == 0 || htab->map.key_size == 0 || - htab->map.value_size == 0) - goto free_htab; + bpf_map_init_from_attr(&htab->map, attr); if (percpu_lru) { /* ensure each CPU's lru list has >=1 elements. @@ -304,22 +329,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) /* hash table size must be power of 2 */ htab->n_buckets = roundup_pow_of_two(htab->map.max_entries); - err = -E2BIG; - if (htab->map.key_size > MAX_BPF_STACK) - /* eBPF programs initialize keys on stack, so they cannot be - * larger than max stack size - */ - goto free_htab; - - if (htab->map.value_size >= KMALLOC_MAX_SIZE - - MAX_BPF_STACK - sizeof(struct htab_elem)) - /* if value_size is bigger, the user space won't be able to - * access the elements via bpf syscall. This check also makes - * sure that the elem_size doesn't overflow and it's - * kmalloc-able later in htab_map_update_elem() - */ - goto free_htab; - htab->elem_size = sizeof(struct htab_elem) + round_up(htab->map.key_size, 8); if (percpu) @@ -327,6 +336,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) else htab->elem_size += round_up(htab->map.value_size, 8); + err = -E2BIG; /* prevent zero size kmalloc and check for u32 overflow */ if (htab->n_buckets == 0 || htab->n_buckets > U32_MAX / sizeof(struct bucket)) @@ -1143,6 +1153,7 @@ static void htab_map_free(struct bpf_map *map) } const struct bpf_map_ops htab_map_ops = { + .map_alloc_check = htab_map_alloc_check, .map_alloc = htab_map_alloc, .map_free = htab_map_free, .map_get_next_key = htab_map_get_next_key, @@ -1153,6 +1164,7 @@ const struct bpf_map_ops htab_map_ops = { }; const struct bpf_map_ops htab_lru_map_ops = { + .map_alloc_check = htab_map_alloc_check, .map_alloc = htab_map_alloc, .map_free = htab_map_free, .map_get_next_key = htab_map_get_next_key, @@ -1236,6 +1248,7 @@ int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, } const struct bpf_map_ops htab_percpu_map_ops = { + .map_alloc_check = htab_map_alloc_check, .map_alloc = htab_map_alloc, .map_free = htab_map_free, .map_get_next_key = htab_map_get_next_key, @@ -1245,6 +1258,7 @@ const struct bpf_map_ops htab_percpu_map_ops = { }; const struct bpf_map_ops htab_lru_percpu_map_ops = { + .map_alloc_check = htab_map_alloc_check, .map_alloc = htab_map_alloc, .map_free = htab_map_free, .map_get_next_key = htab_map_get_next_key, @@ -1253,11 +1267,11 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = { .map_delete_elem = htab_lru_map_delete_elem, }; -static struct bpf_map *fd_htab_map_alloc(union bpf_attr *attr) +static int fd_htab_map_alloc_check(union bpf_attr *attr) { if (attr->value_size != sizeof(u32)) - return ERR_PTR(-EINVAL); - return htab_map_alloc(attr); + return -EINVAL; + return htab_map_alloc_check(attr); } static void fd_htab_map_free(struct bpf_map *map) @@ -1328,7 +1342,7 @@ static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr) if (IS_ERR(inner_map_meta)) return inner_map_meta; - map = fd_htab_map_alloc(attr); + map = htab_map_alloc(attr); if (IS_ERR(map)) { bpf_map_meta_free(inner_map_meta); return map; @@ -1372,6 +1386,7 @@ static void htab_of_map_free(struct bpf_map *map) } const struct bpf_map_ops htab_of_maps_map_ops = { + .map_alloc_check = fd_htab_map_alloc_check, .map_alloc = htab_of_map_alloc, .map_free = htab_of_map_free, .map_get_next_key = htab_map_get_next_key, diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c index 5bb5e49ef4c3..81e2f6995adb 100644 --- a/kernel/bpf/inode.c +++ b/kernel/bpf/inode.c @@ -150,39 +150,29 @@ static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) return 0; } -static int bpf_mkobj_ops(struct inode *dir, struct dentry *dentry, - umode_t mode, const struct inode_operations *iops) +static int bpf_mkobj_ops(struct dentry *dentry, umode_t mode, void *raw, + const struct inode_operations *iops) { - struct inode *inode; - - inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFREG); + struct inode *dir = dentry->d_parent->d_inode; + struct inode *inode = bpf_get_inode(dir->i_sb, dir, mode); if (IS_ERR(inode)) return PTR_ERR(inode); inode->i_op = iops; - inode->i_private = dentry->d_fsdata; + inode->i_private = raw; bpf_dentry_finalize(dentry, inode, dir); return 0; } -static int bpf_mkobj(struct inode *dir, struct dentry *dentry, umode_t mode, - dev_t devt) +static int bpf_mkprog(struct dentry *dentry, umode_t mode, void *arg) { - enum bpf_type type = MINOR(devt); - - if (MAJOR(devt) != UNNAMED_MAJOR || !S_ISREG(mode) || - dentry->d_fsdata == NULL) - return -EPERM; + return bpf_mkobj_ops(dentry, mode, arg, &bpf_prog_iops); +} - switch (type) { - case BPF_TYPE_PROG: - return bpf_mkobj_ops(dir, dentry, mode, &bpf_prog_iops); - case BPF_TYPE_MAP: - return bpf_mkobj_ops(dir, dentry, mode, &bpf_map_iops); - default: - return -EPERM; - } +static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg) +{ + return bpf_mkobj_ops(dentry, mode, arg, &bpf_map_iops); } static struct dentry * @@ -218,7 +208,6 @@ static int bpf_symlink(struct inode *dir, struct dentry *dentry, static const struct inode_operations bpf_dir_iops = { .lookup = bpf_lookup, - .mknod = bpf_mkobj, .mkdir = bpf_mkdir, .symlink = bpf_symlink, .rmdir = simple_rmdir, @@ -234,7 +223,6 @@ static int bpf_obj_do_pin(const struct filename *pathname, void *raw, struct inode *dir; struct path path; umode_t mode; - dev_t devt; int ret; dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0); @@ -242,9 +230,8 @@ static int bpf_obj_do_pin(const struct filename *pathname, void *raw, return PTR_ERR(dentry); mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask()); - devt = MKDEV(UNNAMED_MAJOR, type); - ret = security_path_mknod(&path, dentry, mode, devt); + ret = security_path_mknod(&path, dentry, mode, 0); if (ret) goto out; @@ -254,9 +241,16 @@ static int bpf_obj_do_pin(const struct filename *pathname, void *raw, goto out; } - dentry->d_fsdata = raw; - ret = vfs_mknod(dir, dentry, mode, devt); - dentry->d_fsdata = NULL; + switch (type) { + case BPF_TYPE_PROG: + ret = vfs_mkobj(dentry, mode, bpf_mkprog, raw); + break; + case BPF_TYPE_MAP: + ret = vfs_mkobj(dentry, mode, bpf_mkmap, raw); + break; + default: + ret = -EPERM; + } out: done_path_create(&path, dentry); return ret; diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c index 885e45479680..7b469d10d0e9 100644 --- a/kernel/bpf/lpm_trie.c +++ b/kernel/bpf/lpm_trie.c @@ -522,12 +522,7 @@ static struct bpf_map *trie_alloc(union bpf_attr *attr) return ERR_PTR(-ENOMEM); /* copy mandatory map attributes */ - trie->map.map_type = attr->map_type; - trie->map.key_size = attr->key_size; - trie->map.value_size = attr->value_size; - trie->map.max_entries = attr->max_entries; - trie->map.map_flags = attr->map_flags; - trie->map.numa_node = bpf_map_attr_numa_node(attr); + bpf_map_init_from_attr(&trie->map, attr); trie->data_size = attr->key_size - offsetof(struct bpf_lpm_trie_key, data); trie->max_prefixlen = trie->data_size * 8; @@ -596,9 +591,96 @@ unlock: raw_spin_unlock(&trie->lock); } -static int trie_get_next_key(struct bpf_map *map, void *key, void *next_key) +static int trie_get_next_key(struct bpf_map *map, void *_key, void *_next_key) { - return -ENOTSUPP; + struct lpm_trie_node *node, *next_node = NULL, *parent, *search_root; + struct lpm_trie *trie = container_of(map, struct lpm_trie, map); + struct bpf_lpm_trie_key *key = _key, *next_key = _next_key; + struct lpm_trie_node **node_stack = NULL; + int err = 0, stack_ptr = -1; + unsigned int next_bit; + size_t matchlen; + + /* The get_next_key follows postorder. For the 4 node example in + * the top of this file, the trie_get_next_key() returns the following + * one after another: + * 192.168.0.0/24 + * 192.168.1.0/24 + * 192.168.128.0/24 + * 192.168.0.0/16 + * + * The idea is to return more specific keys before less specific ones. + */ + + /* Empty trie */ + search_root = rcu_dereference(trie->root); + if (!search_root) + return -ENOENT; + + /* For invalid key, find the leftmost node in the trie */ + if (!key || key->prefixlen > trie->max_prefixlen) + goto find_leftmost; + + node_stack = kmalloc(trie->max_prefixlen * sizeof(struct lpm_trie_node *), + GFP_ATOMIC | __GFP_NOWARN); + if (!node_stack) + return -ENOMEM; + + /* Try to find the exact node for the given key */ + for (node = search_root; node;) { + node_stack[++stack_ptr] = node; + matchlen = longest_prefix_match(trie, node, key); + if (node->prefixlen != matchlen || + node->prefixlen == key->prefixlen) + break; + + next_bit = extract_bit(key->data, node->prefixlen); + node = rcu_dereference(node->child[next_bit]); + } + if (!node || node->prefixlen != key->prefixlen || + (node->flags & LPM_TREE_NODE_FLAG_IM)) + goto find_leftmost; + + /* The node with the exactly-matching key has been found, + * find the first node in postorder after the matched node. + */ + node = node_stack[stack_ptr]; + while (stack_ptr > 0) { + parent = node_stack[stack_ptr - 1]; + if (rcu_dereference(parent->child[0]) == node) { + search_root = rcu_dereference(parent->child[1]); + if (search_root) + goto find_leftmost; + } + if (!(parent->flags & LPM_TREE_NODE_FLAG_IM)) { + next_node = parent; + goto do_copy; + } + + node = parent; + stack_ptr--; + } + + /* did not find anything */ + err = -ENOENT; + goto free_stack; + +find_leftmost: + /* Find the leftmost non-intermediate node, all intermediate nodes + * have exact two children, so this function will never return NULL. + */ + for (node = search_root; node;) { + if (!(node->flags & LPM_TREE_NODE_FLAG_IM)) + next_node = node; + node = rcu_dereference(node->child[0]); + } +do_copy: + next_key->prefixlen = next_node->prefixlen; + memcpy((void *)next_key + offsetof(struct bpf_lpm_trie_key, data), + next_node->data, trie->data_size); +free_stack: + kfree(node_stack); + return err; } const struct bpf_map_ops trie_map_ops = { diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c index 8455b89d1bbf..c9401075b58c 100644 --- a/kernel/bpf/offload.c +++ b/kernel/bpf/offload.c @@ -16,18 +16,35 @@ #include <linux/bpf.h> #include <linux/bpf_verifier.h> #include <linux/bug.h> +#include <linux/kdev_t.h> #include <linux/list.h> #include <linux/netdevice.h> #include <linux/printk.h> +#include <linux/proc_ns.h> #include <linux/rtnetlink.h> +#include <linux/rwsem.h> -/* protected by RTNL */ +/* Protects bpf_prog_offload_devs, bpf_map_offload_devs and offload members + * of all progs. + * RTNL lock cannot be taken when holding this lock. + */ +static DECLARE_RWSEM(bpf_devs_lock); static LIST_HEAD(bpf_prog_offload_devs); +static LIST_HEAD(bpf_map_offload_devs); + +static int bpf_dev_offload_check(struct net_device *netdev) +{ + if (!netdev) + return -EINVAL; + if (!netdev->netdev_ops->ndo_bpf) + return -EOPNOTSUPP; + return 0; +} int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr) { - struct net *net = current->nsproxy->net_ns; - struct bpf_dev_offload *offload; + struct bpf_prog_offload *offload; + int err; if (attr->prog_type != BPF_PROG_TYPE_SCHED_CLS && attr->prog_type != BPF_PROG_TYPE_XDP) @@ -41,34 +58,44 @@ int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr) return -ENOMEM; offload->prog = prog; - init_waitqueue_head(&offload->verifier_done); - rtnl_lock(); - offload->netdev = __dev_get_by_index(net, attr->prog_ifindex); - if (!offload->netdev) { - rtnl_unlock(); - kfree(offload); - return -EINVAL; - } + offload->netdev = dev_get_by_index(current->nsproxy->net_ns, + attr->prog_ifindex); + err = bpf_dev_offload_check(offload->netdev); + if (err) + goto err_maybe_put; + down_write(&bpf_devs_lock); + if (offload->netdev->reg_state != NETREG_REGISTERED) { + err = -EINVAL; + goto err_unlock; + } prog->aux->offload = offload; list_add_tail(&offload->offloads, &bpf_prog_offload_devs); - rtnl_unlock(); + dev_put(offload->netdev); + up_write(&bpf_devs_lock); return 0; +err_unlock: + up_write(&bpf_devs_lock); +err_maybe_put: + if (offload->netdev) + dev_put(offload->netdev); + kfree(offload); + return err; } static int __bpf_offload_ndo(struct bpf_prog *prog, enum bpf_netdev_command cmd, struct netdev_bpf *data) { - struct net_device *netdev = prog->aux->offload->netdev; + struct bpf_prog_offload *offload = prog->aux->offload; + struct net_device *netdev; ASSERT_RTNL(); - if (!netdev) + if (!offload) return -ENODEV; - if (!netdev->netdev_ops->ndo_bpf) - return -EOPNOTSUPP; + netdev = offload->netdev; data->command = cmd; @@ -87,62 +114,63 @@ int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env) if (err) goto exit_unlock; - env->dev_ops = data.verifier.ops; - + env->prog->aux->offload->dev_ops = data.verifier.ops; env->prog->aux->offload->dev_state = true; - env->prog->aux->offload->verifier_running = true; exit_unlock: rtnl_unlock(); return err; } +int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env, + int insn_idx, int prev_insn_idx) +{ + struct bpf_prog_offload *offload; + int ret = -ENODEV; + + down_read(&bpf_devs_lock); + offload = env->prog->aux->offload; + if (offload) + ret = offload->dev_ops->insn_hook(env, insn_idx, prev_insn_idx); + up_read(&bpf_devs_lock); + + return ret; +} + static void __bpf_prog_offload_destroy(struct bpf_prog *prog) { - struct bpf_dev_offload *offload = prog->aux->offload; + struct bpf_prog_offload *offload = prog->aux->offload; struct netdev_bpf data = {}; - /* Caution - if netdev is destroyed before the program, this function - * will be called twice. - */ - data.offload.prog = prog; - if (offload->verifier_running) - wait_event(offload->verifier_done, !offload->verifier_running); - if (offload->dev_state) WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data)); - offload->dev_state = false; + /* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */ + bpf_prog_free_id(prog, true); + list_del_init(&offload->offloads); - offload->netdev = NULL; + kfree(offload); + prog->aux->offload = NULL; } void bpf_prog_offload_destroy(struct bpf_prog *prog) { - struct bpf_dev_offload *offload = prog->aux->offload; - - offload->verifier_running = false; - wake_up(&offload->verifier_done); - rtnl_lock(); - __bpf_prog_offload_destroy(prog); + down_write(&bpf_devs_lock); + if (prog->aux->offload) + __bpf_prog_offload_destroy(prog); + up_write(&bpf_devs_lock); rtnl_unlock(); - - kfree(offload); } static int bpf_prog_offload_translate(struct bpf_prog *prog) { - struct bpf_dev_offload *offload = prog->aux->offload; struct netdev_bpf data = {}; int ret; data.offload.prog = prog; - offload->verifier_running = false; - wake_up(&offload->verifier_done); - rtnl_lock(); ret = __bpf_offload_ndo(prog, BPF_OFFLOAD_TRANSLATE, &data); rtnl_unlock(); @@ -164,14 +192,323 @@ int bpf_prog_offload_compile(struct bpf_prog *prog) return bpf_prog_offload_translate(prog); } +struct ns_get_path_bpf_prog_args { + struct bpf_prog *prog; + struct bpf_prog_info *info; +}; + +static struct ns_common *bpf_prog_offload_info_fill_ns(void *private_data) +{ + struct ns_get_path_bpf_prog_args *args = private_data; + struct bpf_prog_aux *aux = args->prog->aux; + struct ns_common *ns; + struct net *net; + + rtnl_lock(); + down_read(&bpf_devs_lock); + + if (aux->offload) { + args->info->ifindex = aux->offload->netdev->ifindex; + net = dev_net(aux->offload->netdev); + get_net(net); + ns = &net->ns; + } else { + args->info->ifindex = 0; + ns = NULL; + } + + up_read(&bpf_devs_lock); + rtnl_unlock(); + + return ns; +} + +int bpf_prog_offload_info_fill(struct bpf_prog_info *info, + struct bpf_prog *prog) +{ + struct ns_get_path_bpf_prog_args args = { + .prog = prog, + .info = info, + }; + struct bpf_prog_aux *aux = prog->aux; + struct inode *ns_inode; + struct path ns_path; + char __user *uinsns; + void *res; + u32 ulen; + + res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args); + if (IS_ERR(res)) { + if (!info->ifindex) + return -ENODEV; + return PTR_ERR(res); + } + + down_read(&bpf_devs_lock); + + if (!aux->offload) { + up_read(&bpf_devs_lock); + return -ENODEV; + } + + ulen = info->jited_prog_len; + info->jited_prog_len = aux->offload->jited_len; + if (info->jited_prog_len & ulen) { + uinsns = u64_to_user_ptr(info->jited_prog_insns); + ulen = min_t(u32, info->jited_prog_len, ulen); + if (copy_to_user(uinsns, aux->offload->jited_image, ulen)) { + up_read(&bpf_devs_lock); + return -EFAULT; + } + } + + up_read(&bpf_devs_lock); + + ns_inode = ns_path.dentry->d_inode; + info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev); + info->netns_ino = ns_inode->i_ino; + path_put(&ns_path); + + return 0; +} + const struct bpf_prog_ops bpf_offload_prog_ops = { }; +static int bpf_map_offload_ndo(struct bpf_offloaded_map *offmap, + enum bpf_netdev_command cmd) +{ + struct netdev_bpf data = {}; + struct net_device *netdev; + + ASSERT_RTNL(); + + data.command = cmd; + data.offmap = offmap; + /* Caller must make sure netdev is valid */ + netdev = offmap->netdev; + + return netdev->netdev_ops->ndo_bpf(netdev, &data); +} + +struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr) +{ + struct net *net = current->nsproxy->net_ns; + struct bpf_offloaded_map *offmap; + int err; + + if (!capable(CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + if (attr->map_type != BPF_MAP_TYPE_ARRAY && + attr->map_type != BPF_MAP_TYPE_HASH) + return ERR_PTR(-EINVAL); + + offmap = kzalloc(sizeof(*offmap), GFP_USER); + if (!offmap) + return ERR_PTR(-ENOMEM); + + bpf_map_init_from_attr(&offmap->map, attr); + + rtnl_lock(); + down_write(&bpf_devs_lock); + offmap->netdev = __dev_get_by_index(net, attr->map_ifindex); + err = bpf_dev_offload_check(offmap->netdev); + if (err) + goto err_unlock; + + err = bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_ALLOC); + if (err) + goto err_unlock; + + list_add_tail(&offmap->offloads, &bpf_map_offload_devs); + up_write(&bpf_devs_lock); + rtnl_unlock(); + + return &offmap->map; + +err_unlock: + up_write(&bpf_devs_lock); + rtnl_unlock(); + kfree(offmap); + return ERR_PTR(err); +} + +static void __bpf_map_offload_destroy(struct bpf_offloaded_map *offmap) +{ + WARN_ON(bpf_map_offload_ndo(offmap, BPF_OFFLOAD_MAP_FREE)); + /* Make sure BPF_MAP_GET_NEXT_ID can't find this dead map */ + bpf_map_free_id(&offmap->map, true); + list_del_init(&offmap->offloads); + offmap->netdev = NULL; +} + +void bpf_map_offload_map_free(struct bpf_map *map) +{ + struct bpf_offloaded_map *offmap = map_to_offmap(map); + + rtnl_lock(); + down_write(&bpf_devs_lock); + if (offmap->netdev) + __bpf_map_offload_destroy(offmap); + up_write(&bpf_devs_lock); + rtnl_unlock(); + + kfree(offmap); +} + +int bpf_map_offload_lookup_elem(struct bpf_map *map, void *key, void *value) +{ + struct bpf_offloaded_map *offmap = map_to_offmap(map); + int ret = -ENODEV; + + down_read(&bpf_devs_lock); + if (offmap->netdev) + ret = offmap->dev_ops->map_lookup_elem(offmap, key, value); + up_read(&bpf_devs_lock); + + return ret; +} + +int bpf_map_offload_update_elem(struct bpf_map *map, + void *key, void *value, u64 flags) +{ + struct bpf_offloaded_map *offmap = map_to_offmap(map); + int ret = -ENODEV; + + if (unlikely(flags > BPF_EXIST)) + return -EINVAL; + + down_read(&bpf_devs_lock); + if (offmap->netdev) + ret = offmap->dev_ops->map_update_elem(offmap, key, value, + flags); + up_read(&bpf_devs_lock); + + return ret; +} + +int bpf_map_offload_delete_elem(struct bpf_map *map, void *key) +{ + struct bpf_offloaded_map *offmap = map_to_offmap(map); + int ret = -ENODEV; + + down_read(&bpf_devs_lock); + if (offmap->netdev) + ret = offmap->dev_ops->map_delete_elem(offmap, key); + up_read(&bpf_devs_lock); + + return ret; +} + +int bpf_map_offload_get_next_key(struct bpf_map *map, void *key, void *next_key) +{ + struct bpf_offloaded_map *offmap = map_to_offmap(map); + int ret = -ENODEV; + + down_read(&bpf_devs_lock); + if (offmap->netdev) + ret = offmap->dev_ops->map_get_next_key(offmap, key, next_key); + up_read(&bpf_devs_lock); + + return ret; +} + +struct ns_get_path_bpf_map_args { + struct bpf_offloaded_map *offmap; + struct bpf_map_info *info; +}; + +static struct ns_common *bpf_map_offload_info_fill_ns(void *private_data) +{ + struct ns_get_path_bpf_map_args *args = private_data; + struct ns_common *ns; + struct net *net; + + rtnl_lock(); + down_read(&bpf_devs_lock); + + if (args->offmap->netdev) { + args->info->ifindex = args->offmap->netdev->ifindex; + net = dev_net(args->offmap->netdev); + get_net(net); + ns = &net->ns; + } else { + args->info->ifindex = 0; + ns = NULL; + } + + up_read(&bpf_devs_lock); + rtnl_unlock(); + + return ns; +} + +int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map) +{ + struct ns_get_path_bpf_map_args args = { + .offmap = map_to_offmap(map), + .info = info, + }; + struct inode *ns_inode; + struct path ns_path; + void *res; + + res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args); + if (IS_ERR(res)) { + if (!info->ifindex) + return -ENODEV; + return PTR_ERR(res); + } + + ns_inode = ns_path.dentry->d_inode; + info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev); + info->netns_ino = ns_inode->i_ino; + path_put(&ns_path); + + return 0; +} + +bool bpf_offload_dev_match(struct bpf_prog *prog, struct bpf_map *map) +{ + struct bpf_offloaded_map *offmap; + struct bpf_prog_offload *offload; + bool ret; + + if (!bpf_prog_is_dev_bound(prog->aux) || !bpf_map_is_dev_bound(map)) + return false; + + down_read(&bpf_devs_lock); + offload = prog->aux->offload; + offmap = map_to_offmap(map); + + ret = offload && offload->netdev == offmap->netdev; + up_read(&bpf_devs_lock); + + return ret; +} + +static void bpf_offload_orphan_all_progs(struct net_device *netdev) +{ + struct bpf_prog_offload *offload, *tmp; + + list_for_each_entry_safe(offload, tmp, &bpf_prog_offload_devs, offloads) + if (offload->netdev == netdev) + __bpf_prog_offload_destroy(offload->prog); +} + +static void bpf_offload_orphan_all_maps(struct net_device *netdev) +{ + struct bpf_offloaded_map *offmap, *tmp; + + list_for_each_entry_safe(offmap, tmp, &bpf_map_offload_devs, offloads) + if (offmap->netdev == netdev) + __bpf_map_offload_destroy(offmap); +} + static int bpf_offload_notification(struct notifier_block *notifier, ulong event, void *ptr) { struct net_device *netdev = netdev_notifier_info_to_dev(ptr); - struct bpf_dev_offload *offload, *tmp; ASSERT_RTNL(); @@ -181,11 +518,10 @@ static int bpf_offload_notification(struct notifier_block *notifier, if (netdev->reg_state != NETREG_UNREGISTERING) break; - list_for_each_entry_safe(offload, tmp, &bpf_prog_offload_devs, - offloads) { - if (offload->netdev == netdev) - __bpf_prog_offload_destroy(offload->prog); - } + down_write(&bpf_devs_lock); + bpf_offload_orphan_all_progs(netdev); + bpf_offload_orphan_all_maps(netdev); + up_write(&bpf_devs_lock); break; default: break; diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 1712d319c2d8..48c33417d13c 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -86,9 +86,10 @@ struct smap_psock { struct work_struct tx_work; struct work_struct gc_work; + struct proto *sk_proto; + void (*save_close)(struct sock *sk, long timeout); void (*save_data_ready)(struct sock *sk); void (*save_write_space)(struct sock *sk); - void (*save_state_change)(struct sock *sk); }; static inline struct smap_psock *smap_psock_sk(const struct sock *sk) @@ -96,12 +97,78 @@ static inline struct smap_psock *smap_psock_sk(const struct sock *sk) return rcu_dereference_sk_user_data(sk); } -/* compute the linear packet data range [data, data_end) for skb when - * sk_skb type programs are in use. - */ -static inline void bpf_compute_data_end_sk_skb(struct sk_buff *skb) +static struct proto tcp_bpf_proto; +static int bpf_tcp_init(struct sock *sk) { - TCP_SKB_CB(skb)->bpf.data_end = skb->data + skb_headlen(skb); + struct smap_psock *psock; + + rcu_read_lock(); + psock = smap_psock_sk(sk); + if (unlikely(!psock)) { + rcu_read_unlock(); + return -EINVAL; + } + + if (unlikely(psock->sk_proto)) { + rcu_read_unlock(); + return -EBUSY; + } + + psock->save_close = sk->sk_prot->close; + psock->sk_proto = sk->sk_prot; + sk->sk_prot = &tcp_bpf_proto; + rcu_read_unlock(); + return 0; +} + +static void bpf_tcp_release(struct sock *sk) +{ + struct smap_psock *psock; + + rcu_read_lock(); + psock = smap_psock_sk(sk); + + if (likely(psock)) { + sk->sk_prot = psock->sk_proto; + psock->sk_proto = NULL; + } + rcu_read_unlock(); +} + +static void smap_release_sock(struct smap_psock *psock, struct sock *sock); + +static void bpf_tcp_close(struct sock *sk, long timeout) +{ + void (*close_fun)(struct sock *sk, long timeout); + struct smap_psock_map_entry *e, *tmp; + struct smap_psock *psock; + struct sock *osk; + + rcu_read_lock(); + psock = smap_psock_sk(sk); + if (unlikely(!psock)) { + rcu_read_unlock(); + return sk->sk_prot->close(sk, timeout); + } + + /* The psock may be destroyed anytime after exiting the RCU critial + * section so by the time we use close_fun the psock may no longer + * be valid. However, bpf_tcp_close is called with the sock lock + * held so the close hook and sk are still valid. + */ + close_fun = psock->save_close; + + write_lock_bh(&sk->sk_callback_lock); + list_for_each_entry_safe(e, tmp, &psock->maps, list) { + osk = cmpxchg(e->entry, sk, NULL); + if (osk == sk) { + list_del(&e->list); + smap_release_sock(psock, sk); + } + } + write_unlock_bh(&sk->sk_callback_lock); + rcu_read_unlock(); + close_fun(sk, timeout); } enum __sk_action { @@ -110,6 +177,22 @@ enum __sk_action { __SK_REDIRECT, }; +static struct tcp_ulp_ops bpf_tcp_ulp_ops __read_mostly = { + .name = "bpf_tcp", + .uid = TCP_ULP_BPF, + .user_visible = false, + .owner = NULL, + .init = bpf_tcp_init, + .release = bpf_tcp_release, +}; + +static int bpf_tcp_ulp_register(void) +{ + tcp_bpf_proto = tcp_prot; + tcp_bpf_proto.close = bpf_tcp_close; + return tcp_register_ulp(&bpf_tcp_ulp_ops); +} + static int smap_verdict_func(struct smap_psock *psock, struct sk_buff *skb) { struct bpf_prog *prog = READ_ONCE(psock->bpf_verdict); @@ -174,68 +257,6 @@ static void smap_report_sk_error(struct smap_psock *psock, int err) sk->sk_error_report(sk); } -static void smap_release_sock(struct smap_psock *psock, struct sock *sock); - -/* Called with lock_sock(sk) held */ -static void smap_state_change(struct sock *sk) -{ - struct smap_psock_map_entry *e, *tmp; - struct smap_psock *psock; - struct socket_wq *wq; - struct sock *osk; - - rcu_read_lock(); - - /* Allowing transitions into an established syn_recv states allows - * for early binding sockets to a smap object before the connection - * is established. - */ - switch (sk->sk_state) { - case TCP_SYN_SENT: - case TCP_SYN_RECV: - case TCP_ESTABLISHED: - break; - case TCP_CLOSE_WAIT: - case TCP_CLOSING: - case TCP_LAST_ACK: - case TCP_FIN_WAIT1: - case TCP_FIN_WAIT2: - case TCP_LISTEN: - break; - case TCP_CLOSE: - /* Only release if the map entry is in fact the sock in - * question. There is a case where the operator deletes - * the sock from the map, but the TCP sock is closed before - * the psock is detached. Use cmpxchg to verify correct - * sock is removed. - */ - psock = smap_psock_sk(sk); - if (unlikely(!psock)) - break; - write_lock_bh(&sk->sk_callback_lock); - list_for_each_entry_safe(e, tmp, &psock->maps, list) { - osk = cmpxchg(e->entry, sk, NULL); - if (osk == sk) { - list_del(&e->list); - smap_release_sock(psock, sk); - } - } - write_unlock_bh(&sk->sk_callback_lock); - break; - default: - psock = smap_psock_sk(sk); - if (unlikely(!psock)) - break; - smap_report_sk_error(psock, EPIPE); - break; - } - - wq = rcu_dereference(sk->sk_wq); - if (skwq_has_sleeper(wq)) - wake_up_interruptible_all(&wq->wait); - rcu_read_unlock(); -} - static void smap_read_sock_strparser(struct strparser *strp, struct sk_buff *skb) { @@ -330,10 +351,8 @@ static void smap_stop_sock(struct smap_psock *psock, struct sock *sk) return; sk->sk_data_ready = psock->save_data_ready; sk->sk_write_space = psock->save_write_space; - sk->sk_state_change = psock->save_state_change; psock->save_data_ready = NULL; psock->save_write_space = NULL; - psock->save_state_change = NULL; strp_stop(&psock->strp); psock->strp_enabled = false; } @@ -358,6 +377,7 @@ static void smap_release_sock(struct smap_psock *psock, struct sock *sock) if (psock->refcnt) return; + tcp_cleanup_ulp(sock); smap_stop_sock(psock, sock); clear_bit(SMAP_TX_RUNNING, &psock->state); rcu_assign_sk_user_data(sock, NULL); @@ -435,10 +455,8 @@ static void smap_start_sock(struct smap_psock *psock, struct sock *sk) return; psock->save_data_ready = sk->sk_data_ready; psock->save_write_space = sk->sk_write_space; - psock->save_state_change = sk->sk_state_change; sk->sk_data_ready = smap_data_ready; sk->sk_write_space = smap_write_space; - sk->sk_state_change = smap_state_change; psock->strp_enabled = true; } @@ -517,17 +535,15 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr) if (attr->value_size > KMALLOC_MAX_SIZE) return ERR_PTR(-E2BIG); + err = bpf_tcp_ulp_register(); + if (err && err != -EEXIST) + return ERR_PTR(err); + stab = kzalloc(sizeof(*stab), GFP_USER); if (!stab) return ERR_PTR(-ENOMEM); - /* mandatory map attributes */ - stab->map.map_type = attr->map_type; - stab->map.key_size = attr->key_size; - stab->map.value_size = attr->value_size; - stab->map.max_entries = attr->max_entries; - stab->map.map_flags = attr->map_flags; - stab->map.numa_node = bpf_map_attr_numa_node(attr); + bpf_map_init_from_attr(&stab->map, attr); /* make sure page count doesn't overflow */ cost = (u64) stab->map.max_entries * sizeof(struct sock *); @@ -604,11 +620,6 @@ static void sock_map_free(struct bpf_map *map) } rcu_read_unlock(); - if (stab->bpf_verdict) - bpf_prog_put(stab->bpf_verdict); - if (stab->bpf_parse) - bpf_prog_put(stab->bpf_parse); - sock_map_remove_complete(stab); } @@ -768,6 +779,10 @@ static int sock_map_ctx_update_elem(struct bpf_sock_ops_kern *skops, goto out_progs; } + err = tcp_set_ulp_id(sock, TCP_ULP_BPF); + if (err) + goto out_progs; + set_bit(SMAP_TX_RUNNING, &psock->state); } @@ -880,6 +895,19 @@ static int sock_map_update_elem(struct bpf_map *map, return err; } +static void sock_map_release(struct bpf_map *map, struct file *map_file) +{ + struct bpf_stab *stab = container_of(map, struct bpf_stab, map); + struct bpf_prog *orig; + + orig = xchg(&stab->bpf_parse, NULL); + if (orig) + bpf_prog_put(orig); + orig = xchg(&stab->bpf_verdict, NULL); + if (orig) + bpf_prog_put(orig); +} + const struct bpf_map_ops sock_map_ops = { .map_alloc = sock_map_alloc, .map_free = sock_map_free, @@ -887,6 +915,7 @@ const struct bpf_map_ops sock_map_ops = { .map_get_next_key = sock_map_get_next_key, .map_update_elem = sock_map_update_elem, .map_delete_elem = sock_map_delete_elem, + .map_release = sock_map_release, }; BPF_CALL_4(bpf_sock_map_update, struct bpf_sock_ops_kern *, bpf_sock, diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index a15bc636cc98..b0ecf43f5894 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -88,14 +88,10 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr) if (cost >= U32_MAX - PAGE_SIZE) goto free_smap; - smap->map.map_type = attr->map_type; - smap->map.key_size = attr->key_size; + bpf_map_init_from_attr(&smap->map, attr); smap->map.value_size = value_size; - smap->map.max_entries = attr->max_entries; - smap->map.map_flags = attr->map_flags; smap->n_buckets = n_buckets; smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; - smap->map.numa_node = bpf_map_attr_numa_node(attr); err = bpf_map_precharge_memlock(smap->map.pages); if (err) @@ -226,9 +222,33 @@ int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value) return 0; } -static int stack_map_get_next_key(struct bpf_map *map, void *key, void *next_key) +static int stack_map_get_next_key(struct bpf_map *map, void *key, + void *next_key) { - return -EINVAL; + struct bpf_stack_map *smap = container_of(map, + struct bpf_stack_map, map); + u32 id; + + WARN_ON_ONCE(!rcu_read_lock_held()); + + if (!key) { + id = 0; + } else { + id = *(u32 *)key; + if (id >= smap->n_buckets || !smap->buckets[id]) + id = 0; + else + id++; + } + + while (id < smap->n_buckets && !smap->buckets[id]) + id++; + + if (id >= smap->n_buckets) + return -ENOENT; + + *(u32 *)next_key = id; + return 0; } static int stack_map_update_elem(struct bpf_map *map, void *key, void *value, diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 5cb783fc8224..e24aa3241387 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -94,18 +94,34 @@ static int check_uarg_tail_zero(void __user *uaddr, return 0; } +const struct bpf_map_ops bpf_map_offload_ops = { + .map_alloc = bpf_map_offload_map_alloc, + .map_free = bpf_map_offload_map_free, +}; + static struct bpf_map *find_and_alloc_map(union bpf_attr *attr) { + const struct bpf_map_ops *ops; struct bpf_map *map; + int err; - if (attr->map_type >= ARRAY_SIZE(bpf_map_types) || - !bpf_map_types[attr->map_type]) + if (attr->map_type >= ARRAY_SIZE(bpf_map_types)) + return ERR_PTR(-EINVAL); + ops = bpf_map_types[attr->map_type]; + if (!ops) return ERR_PTR(-EINVAL); - map = bpf_map_types[attr->map_type]->map_alloc(attr); + if (ops->map_alloc_check) { + err = ops->map_alloc_check(attr); + if (err) + return ERR_PTR(err); + } + if (attr->map_ifindex) + ops = &bpf_map_offload_ops; + map = ops->map_alloc(attr); if (IS_ERR(map)) return map; - map->ops = bpf_map_types[attr->map_type]; + map->ops = ops; map->map_type = attr->map_type; return map; } @@ -134,6 +150,16 @@ void bpf_map_area_free(void *area) kvfree(area); } +void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr) +{ + map->map_type = attr->map_type; + map->key_size = attr->key_size; + map->value_size = attr->value_size; + map->max_entries = attr->max_entries; + map->map_flags = attr->map_flags; + map->numa_node = bpf_map_attr_numa_node(attr); +} + int bpf_map_precharge_memlock(u32 pages) { struct user_struct *user = get_current_user(); @@ -189,16 +215,25 @@ static int bpf_map_alloc_id(struct bpf_map *map) return id > 0 ? 0 : id; } -static void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock) +void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock) { unsigned long flags; + /* Offloaded maps are removed from the IDR store when their device + * disappears - even if someone holds an fd to them they are unusable, + * the memory is gone, all ops will fail; they are simply waiting for + * refcnt to drop to be freed. + */ + if (!map->id) + return; + if (do_idr_lock) spin_lock_irqsave(&map_idr_lock, flags); else __acquire(&map_idr_lock); idr_remove(&map_idr, map->id); + map->id = 0; if (do_idr_lock) spin_unlock_irqrestore(&map_idr_lock, flags); @@ -378,7 +413,7 @@ static int bpf_obj_name_cpy(char *dst, const char *src) return 0; } -#define BPF_MAP_CREATE_LAST_FIELD map_name +#define BPF_MAP_CREATE_LAST_FIELD map_ifindex /* called via syscall */ static int map_create(union bpf_attr *attr) { @@ -566,8 +601,10 @@ static int map_lookup_elem(union bpf_attr *attr) if (!value) goto free_key; - if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || - map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { + if (bpf_map_is_dev_bound(map)) { + err = bpf_map_offload_lookup_elem(map, key, value); + } else if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { err = bpf_percpu_hash_copy(map, key, value); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { err = bpf_percpu_array_copy(map, key, value); @@ -654,7 +691,10 @@ static int map_update_elem(union bpf_attr *attr) goto free_value; /* Need to create a kthread, thus must support schedule */ - if (map->map_type == BPF_MAP_TYPE_CPUMAP) { + if (bpf_map_is_dev_bound(map)) { + err = bpf_map_offload_update_elem(map, key, value, attr->flags); + goto out; + } else if (map->map_type == BPF_MAP_TYPE_CPUMAP) { err = map->ops->map_update_elem(map, key, value, attr->flags); goto out; } @@ -669,10 +709,7 @@ static int map_update_elem(union bpf_attr *attr) err = bpf_percpu_hash_update(map, key, value, attr->flags); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { err = bpf_percpu_array_update(map, key, value, attr->flags); - } else if (map->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || - map->map_type == BPF_MAP_TYPE_PROG_ARRAY || - map->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || - map->map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS) { + } else if (IS_FD_ARRAY(map)) { rcu_read_lock(); err = bpf_fd_array_map_update_elem(map, f.file, key, value, attr->flags); @@ -731,6 +768,11 @@ static int map_delete_elem(union bpf_attr *attr) goto err_put; } + if (bpf_map_is_dev_bound(map)) { + err = bpf_map_offload_delete_elem(map, key); + goto out; + } + preempt_disable(); __this_cpu_inc(bpf_prog_active); rcu_read_lock(); @@ -738,7 +780,7 @@ static int map_delete_elem(union bpf_attr *attr) rcu_read_unlock(); __this_cpu_dec(bpf_prog_active); preempt_enable(); - +out: if (!err) trace_bpf_map_delete_elem(map, ufd, key); kfree(key); @@ -788,9 +830,15 @@ static int map_get_next_key(union bpf_attr *attr) if (!next_key) goto free_key; + if (bpf_map_is_dev_bound(map)) { + err = bpf_map_offload_get_next_key(map, key, next_key); + goto out; + } + rcu_read_lock(); err = map->ops->map_get_next_key(map, key, next_key); rcu_read_unlock(); +out: if (err) goto free_next_key; @@ -905,9 +953,13 @@ static int bpf_prog_alloc_id(struct bpf_prog *prog) return id > 0 ? 0 : id; } -static void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock) +void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock) { - /* cBPF to eBPF migrations are currently not in the idr store. */ + /* cBPF to eBPF migrations are currently not in the idr store. + * Offloaded programs are removed from the store when their device + * disappears - even if someone grabs an fd to them they are unusable, + * simply waiting for refcnt to drop to be freed. + */ if (!prog->aux->id) return; @@ -917,6 +969,7 @@ static void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock) __acquire(&prog_idr_lock); idr_remove(&prog_idr, prog->aux->id); + prog->aux->id = 0; if (do_idr_lock) spin_unlock_bh(&prog_idr_lock); @@ -937,10 +990,16 @@ static void __bpf_prog_put_rcu(struct rcu_head *rcu) static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock) { if (atomic_dec_and_test(&prog->aux->refcnt)) { + int i; + trace_bpf_prog_put_rcu(prog); /* bpf_prog_free_id() must be called first */ bpf_prog_free_id(prog, do_idr_lock); + + for (i = 0; i < prog->aux->func_cnt; i++) + bpf_prog_kallsyms_del(prog->aux->func[i]); bpf_prog_kallsyms_del(prog); + call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu); } } @@ -1151,6 +1210,8 @@ static int bpf_prog_load(union bpf_attr *attr) if (!prog) return -ENOMEM; + prog->aux->offload_requested = !!attr->prog_ifindex; + err = security_bpf_prog_alloc(prog->aux); if (err) goto free_prog_nouncharge; @@ -1172,7 +1233,7 @@ static int bpf_prog_load(union bpf_attr *attr) atomic_set(&prog->aux->refcnt, 1); prog->gpl_compatible = is_gpl ? 1 : 0; - if (attr->prog_ifindex) { + if (bpf_prog_is_dev_bound(prog->aux)) { err = bpf_prog_offload_init(prog, attr); if (err) goto free_prog; @@ -1194,7 +1255,8 @@ static int bpf_prog_load(union bpf_attr *attr) goto free_used_maps; /* eBPF program is ready to be JITed */ - prog = bpf_prog_select_runtime(prog, &err); + if (!prog->bpf_func) + prog = bpf_prog_select_runtime(prog, &err); if (err < 0) goto free_used_maps; @@ -1439,6 +1501,8 @@ static int bpf_prog_test_run(const union bpf_attr *attr, struct bpf_prog *prog; int ret = -ENOTSUPP; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; if (CHECK_ATTR(BPF_PROG_TEST_RUN)) return -EINVAL; @@ -1551,6 +1615,67 @@ static int bpf_map_get_fd_by_id(const union bpf_attr *attr) return fd; } +static const struct bpf_map *bpf_map_from_imm(const struct bpf_prog *prog, + unsigned long addr) +{ + int i; + + for (i = 0; i < prog->aux->used_map_cnt; i++) + if (prog->aux->used_maps[i] == (void *)addr) + return prog->aux->used_maps[i]; + return NULL; +} + +static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog) +{ + const struct bpf_map *map; + struct bpf_insn *insns; + u64 imm; + int i; + + insns = kmemdup(prog->insnsi, bpf_prog_insn_size(prog), + GFP_USER); + if (!insns) + return insns; + + for (i = 0; i < prog->len; i++) { + if (insns[i].code == (BPF_JMP | BPF_TAIL_CALL)) { + insns[i].code = BPF_JMP | BPF_CALL; + insns[i].imm = BPF_FUNC_tail_call; + /* fall-through */ + } + if (insns[i].code == (BPF_JMP | BPF_CALL) || + insns[i].code == (BPF_JMP | BPF_CALL_ARGS)) { + if (insns[i].code == (BPF_JMP | BPF_CALL_ARGS)) + insns[i].code = BPF_JMP | BPF_CALL; + if (!bpf_dump_raw_ok()) + insns[i].imm = 0; + continue; + } + + if (insns[i].code != (BPF_LD | BPF_IMM | BPF_DW)) + continue; + + imm = ((u64)insns[i + 1].imm << 32) | (u32)insns[i].imm; + map = bpf_map_from_imm(prog, imm); + if (map) { + insns[i].src_reg = BPF_PSEUDO_MAP_FD; + insns[i].imm = map->id; + insns[i + 1].imm = 0; + continue; + } + + if (!bpf_dump_raw_ok() && + imm == (unsigned long)prog->aux) { + insns[i].imm = 0; + insns[i + 1].imm = 0; + continue; + } + } + + return insns; +} + static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, const union bpf_attr *attr, union bpf_attr __user *uattr) @@ -1598,24 +1723,51 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, goto done; } - ulen = info.jited_prog_len; - info.jited_prog_len = prog->jited_len; - if (info.jited_prog_len && ulen) { - uinsns = u64_to_user_ptr(info.jited_prog_insns); - ulen = min_t(u32, info.jited_prog_len, ulen); - if (copy_to_user(uinsns, prog->bpf_func, ulen)) - return -EFAULT; - } - ulen = info.xlated_prog_len; info.xlated_prog_len = bpf_prog_insn_size(prog); if (info.xlated_prog_len && ulen) { + struct bpf_insn *insns_sanitized; + bool fault; + + if (prog->blinded && !bpf_dump_raw_ok()) { + info.xlated_prog_insns = 0; + goto done; + } + insns_sanitized = bpf_insn_prepare_dump(prog); + if (!insns_sanitized) + return -ENOMEM; uinsns = u64_to_user_ptr(info.xlated_prog_insns); ulen = min_t(u32, info.xlated_prog_len, ulen); - if (copy_to_user(uinsns, prog->insnsi, ulen)) + fault = copy_to_user(uinsns, insns_sanitized, ulen); + kfree(insns_sanitized); + if (fault) return -EFAULT; } + if (bpf_prog_is_dev_bound(prog->aux)) { + err = bpf_prog_offload_info_fill(&info, prog); + if (err) + return err; + goto done; + } + + /* NOTE: the following code is supposed to be skipped for offload. + * bpf_prog_offload_info_fill() is the place to fill similar fields + * for offload. + */ + ulen = info.jited_prog_len; + info.jited_prog_len = prog->jited_len; + if (info.jited_prog_len && ulen) { + if (bpf_dump_raw_ok()) { + uinsns = u64_to_user_ptr(info.jited_prog_insns); + ulen = min_t(u32, info.jited_prog_len, ulen); + if (copy_to_user(uinsns, prog->bpf_func, ulen)) + return -EFAULT; + } else { + info.jited_prog_insns = 0; + } + } + done: if (copy_to_user(uinfo, &info, info_len) || put_user(info_len, &uattr->info.info_len)) @@ -1646,6 +1798,12 @@ static int bpf_map_get_info_by_fd(struct bpf_map *map, info.map_flags = map->map_flags; memcpy(info.name, map->name, sizeof(map->name)); + if (bpf_map_is_dev_bound(map)) { + err = bpf_map_offload_info_fill(&info, map); + if (err) + return err; + } + if (copy_to_user(uinfo, &info, info_len) || put_user(info_len, &uattr->info.info_len)) return -EFAULT; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 13551e623501..5fb69a85d967 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -20,6 +20,8 @@ #include <linux/file.h> #include <linux/vmalloc.h> #include <linux/stringify.h> +#include <linux/bsearch.h> +#include <linux/sort.h> #include "disasm.h" @@ -167,11 +169,11 @@ struct bpf_call_arg_meta { static DEFINE_MUTEX(bpf_verifier_lock); /* log_level controls verbosity level of eBPF verifier. - * verbose() is used to dump the verification trace to the log, so the user - * can figure out what's wrong with the program + * bpf_verifier_log_write() is used to dump the verification trace to the log, + * so the user can figure out what's wrong with the program */ -static __printf(2, 3) void verbose(struct bpf_verifier_env *env, - const char *fmt, ...) +__printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env, + const char *fmt, ...) { struct bpf_verifer_log *log = &env->log; unsigned int n; @@ -195,6 +197,14 @@ static __printf(2, 3) void verbose(struct bpf_verifier_env *env, else log->ubuf = NULL; } +EXPORT_SYMBOL_GPL(bpf_verifier_log_write); +/* Historically bpf_verifier_log_write was called verbose, but the name was too + * generic for symbol export. The function was renamed, but not the calls in + * the verifier to avoid complicating backports. Hence the alias below. + */ +static __printf(2, 3) void verbose(struct bpf_verifier_env *env, + const char *fmt, ...) + __attribute__((alias("bpf_verifier_log_write"))); static bool type_is_pkt_pointer(enum bpf_reg_type type) { @@ -216,23 +226,48 @@ static const char * const reg_type_str[] = { [PTR_TO_PACKET_END] = "pkt_end", }; +static void print_liveness(struct bpf_verifier_env *env, + enum bpf_reg_liveness live) +{ + if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN)) + verbose(env, "_"); + if (live & REG_LIVE_READ) + verbose(env, "r"); + if (live & REG_LIVE_WRITTEN) + verbose(env, "w"); +} + +static struct bpf_func_state *func(struct bpf_verifier_env *env, + const struct bpf_reg_state *reg) +{ + struct bpf_verifier_state *cur = env->cur_state; + + return cur->frame[reg->frameno]; +} + static void print_verifier_state(struct bpf_verifier_env *env, - struct bpf_verifier_state *state) + const struct bpf_func_state *state) { - struct bpf_reg_state *reg; + const struct bpf_reg_state *reg; enum bpf_reg_type t; int i; + if (state->frameno) + verbose(env, " frame%d:", state->frameno); for (i = 0; i < MAX_BPF_REG; i++) { reg = &state->regs[i]; t = reg->type; if (t == NOT_INIT) continue; - verbose(env, " R%d=%s", i, reg_type_str[t]); + verbose(env, " R%d", i); + print_liveness(env, reg->live); + verbose(env, "=%s", reg_type_str[t]); if ((t == SCALAR_VALUE || t == PTR_TO_STACK) && tnum_is_const(reg->var_off)) { /* reg->off should be 0 for SCALAR_VALUE */ verbose(env, "%lld", reg->var_off.value + reg->off); + if (t == PTR_TO_STACK) + verbose(env, ",call_%d", func(env, reg)->callsite); } else { verbose(env, "(id=%d", reg->id); if (t != SCALAR_VALUE) @@ -277,16 +312,21 @@ static void print_verifier_state(struct bpf_verifier_env *env, } } for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { - if (state->stack[i].slot_type[0] == STACK_SPILL) - verbose(env, " fp%d=%s", - -MAX_BPF_STACK + i * BPF_REG_SIZE, + if (state->stack[i].slot_type[0] == STACK_SPILL) { + verbose(env, " fp%d", + (-i - 1) * BPF_REG_SIZE); + print_liveness(env, state->stack[i].spilled_ptr.live); + verbose(env, "=%s", reg_type_str[state->stack[i].spilled_ptr.type]); + } + if (state->stack[i].slot_type[0] == STACK_ZERO) + verbose(env, " fp%d=0", (-i - 1) * BPF_REG_SIZE); } verbose(env, "\n"); } -static int copy_stack_state(struct bpf_verifier_state *dst, - const struct bpf_verifier_state *src) +static int copy_stack_state(struct bpf_func_state *dst, + const struct bpf_func_state *src) { if (!src->stack) return 0; @@ -302,13 +342,13 @@ static int copy_stack_state(struct bpf_verifier_state *dst, /* do_check() starts with zero-sized stack in struct bpf_verifier_state to * make it consume minimal amount of memory. check_stack_write() access from - * the program calls into realloc_verifier_state() to grow the stack size. + * the program calls into realloc_func_state() to grow the stack size. * Note there is a non-zero 'parent' pointer inside bpf_verifier_state * which this function copies over. It points to previous bpf_verifier_state * which is never reallocated */ -static int realloc_verifier_state(struct bpf_verifier_state *state, int size, - bool copy_old) +static int realloc_func_state(struct bpf_func_state *state, int size, + bool copy_old) { u32 old_size = state->allocated_stack; struct bpf_stack_state *new_stack; @@ -341,10 +381,23 @@ static int realloc_verifier_state(struct bpf_verifier_state *state, int size, return 0; } +static void free_func_state(struct bpf_func_state *state) +{ + if (!state) + return; + kfree(state->stack); + kfree(state); +} + static void free_verifier_state(struct bpf_verifier_state *state, bool free_self) { - kfree(state->stack); + int i; + + for (i = 0; i <= state->curframe; i++) { + free_func_state(state->frame[i]); + state->frame[i] = NULL; + } if (free_self) kfree(state); } @@ -352,18 +405,46 @@ static void free_verifier_state(struct bpf_verifier_state *state, /* copy verifier state from src to dst growing dst stack space * when necessary to accommodate larger src stack */ -static int copy_verifier_state(struct bpf_verifier_state *dst, - const struct bpf_verifier_state *src) +static int copy_func_state(struct bpf_func_state *dst, + const struct bpf_func_state *src) { int err; - err = realloc_verifier_state(dst, src->allocated_stack, false); + err = realloc_func_state(dst, src->allocated_stack, false); if (err) return err; - memcpy(dst, src, offsetof(struct bpf_verifier_state, allocated_stack)); + memcpy(dst, src, offsetof(struct bpf_func_state, allocated_stack)); return copy_stack_state(dst, src); } +static int copy_verifier_state(struct bpf_verifier_state *dst_state, + const struct bpf_verifier_state *src) +{ + struct bpf_func_state *dst; + int i, err; + + /* if dst has more stack frames then src frame, free them */ + for (i = src->curframe + 1; i <= dst_state->curframe; i++) { + free_func_state(dst_state->frame[i]); + dst_state->frame[i] = NULL; + } + dst_state->curframe = src->curframe; + dst_state->parent = src->parent; + for (i = 0; i <= src->curframe; i++) { + dst = dst_state->frame[i]; + if (!dst) { + dst = kzalloc(sizeof(*dst), GFP_KERNEL); + if (!dst) + return -ENOMEM; + dst_state->frame[i] = dst; + } + err = copy_func_state(dst, src->frame[i]); + if (err) + return err; + } + return 0; +} + static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx, int *insn_idx) { @@ -416,6 +497,8 @@ static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, } return &elem->st; err: + free_verifier_state(env->cur_state, true); + env->cur_state = NULL; /* pop all elements and return */ while (!pop_stack(env, NULL, NULL)); return NULL; @@ -425,6 +508,10 @@ err: static const int caller_saved[CALLER_SAVED_REGS] = { BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5 }; +#define CALLEE_SAVED_REGS 5 +static const int callee_saved[CALLEE_SAVED_REGS] = { + BPF_REG_6, BPF_REG_7, BPF_REG_8, BPF_REG_9 +}; static void __mark_reg_not_init(struct bpf_reg_state *reg); @@ -449,6 +536,13 @@ static void __mark_reg_known_zero(struct bpf_reg_state *reg) __mark_reg_known(reg, 0); } +static void __mark_reg_const_zero(struct bpf_reg_state *reg) +{ + __mark_reg_known(reg, 0); + reg->off = 0; + reg->type = SCALAR_VALUE; +} + static void mark_reg_known_zero(struct bpf_verifier_env *env, struct bpf_reg_state *regs, u32 regno) { @@ -560,6 +654,7 @@ static void __mark_reg_unknown(struct bpf_reg_state *reg) reg->id = 0; reg->off = 0; reg->var_off = tnum_unknown; + reg->frameno = 0; __mark_reg_unbounded(reg); } @@ -568,8 +663,8 @@ static void mark_reg_unknown(struct bpf_verifier_env *env, { if (WARN_ON(regno >= MAX_BPF_REG)) { verbose(env, "mark_reg_unknown(regs, %u)\n", regno); - /* Something bad happened, let's kill all regs */ - for (regno = 0; regno < MAX_BPF_REG; regno++) + /* Something bad happened, let's kill all regs except FP */ + for (regno = 0; regno < BPF_REG_FP; regno++) __mark_reg_not_init(regs + regno); return; } @@ -587,8 +682,8 @@ static void mark_reg_not_init(struct bpf_verifier_env *env, { if (WARN_ON(regno >= MAX_BPF_REG)) { verbose(env, "mark_reg_not_init(regs, %u)\n", regno); - /* Something bad happened, let's kill all regs */ - for (regno = 0; regno < MAX_BPF_REG; regno++) + /* Something bad happened, let's kill all regs except FP */ + for (regno = 0; regno < BPF_REG_FP; regno++) __mark_reg_not_init(regs + regno); return; } @@ -596,8 +691,9 @@ static void mark_reg_not_init(struct bpf_verifier_env *env, } static void init_reg_state(struct bpf_verifier_env *env, - struct bpf_reg_state *regs) + struct bpf_func_state *state) { + struct bpf_reg_state *regs = state->regs; int i; for (i = 0; i < MAX_BPF_REG; i++) { @@ -608,41 +704,218 @@ static void init_reg_state(struct bpf_verifier_env *env, /* frame pointer */ regs[BPF_REG_FP].type = PTR_TO_STACK; mark_reg_known_zero(env, regs, BPF_REG_FP); + regs[BPF_REG_FP].frameno = state->frameno; /* 1st arg to a function */ regs[BPF_REG_1].type = PTR_TO_CTX; mark_reg_known_zero(env, regs, BPF_REG_1); } +#define BPF_MAIN_FUNC (-1) +static void init_func_state(struct bpf_verifier_env *env, + struct bpf_func_state *state, + int callsite, int frameno, int subprogno) +{ + state->callsite = callsite; + state->frameno = frameno; + state->subprogno = subprogno; + init_reg_state(env, state); +} + enum reg_arg_type { SRC_OP, /* register is used as source operand */ DST_OP, /* register is used as destination operand */ DST_OP_NO_MARK /* same as above, check only, don't mark */ }; -static void mark_reg_read(const struct bpf_verifier_state *state, u32 regno) +static int cmp_subprogs(const void *a, const void *b) +{ + return *(int *)a - *(int *)b; +} + +static int find_subprog(struct bpf_verifier_env *env, int off) { - struct bpf_verifier_state *parent = state->parent; + u32 *p; + + p = bsearch(&off, env->subprog_starts, env->subprog_cnt, + sizeof(env->subprog_starts[0]), cmp_subprogs); + if (!p) + return -ENOENT; + return p - env->subprog_starts; + +} + +static int add_subprog(struct bpf_verifier_env *env, int off) +{ + int insn_cnt = env->prog->len; + int ret; + + if (off >= insn_cnt || off < 0) { + verbose(env, "call to invalid destination\n"); + return -EINVAL; + } + ret = find_subprog(env, off); + if (ret >= 0) + return 0; + if (env->subprog_cnt >= BPF_MAX_SUBPROGS) { + verbose(env, "too many subprograms\n"); + return -E2BIG; + } + env->subprog_starts[env->subprog_cnt++] = off; + sort(env->subprog_starts, env->subprog_cnt, + sizeof(env->subprog_starts[0]), cmp_subprogs, NULL); + return 0; +} + +static int check_subprogs(struct bpf_verifier_env *env) +{ + int i, ret, subprog_start, subprog_end, off, cur_subprog = 0; + struct bpf_insn *insn = env->prog->insnsi; + int insn_cnt = env->prog->len; + + /* determine subprog starts. The end is one before the next starts */ + for (i = 0; i < insn_cnt; i++) { + if (insn[i].code != (BPF_JMP | BPF_CALL)) + continue; + if (insn[i].src_reg != BPF_PSEUDO_CALL) + continue; + if (!env->allow_ptr_leaks) { + verbose(env, "function calls to other bpf functions are allowed for root only\n"); + return -EPERM; + } + if (bpf_prog_is_dev_bound(env->prog->aux)) { + verbose(env, "function calls in offloaded programs are not supported yet\n"); + return -EINVAL; + } + ret = add_subprog(env, i + insn[i].imm + 1); + if (ret < 0) + return ret; + } + + if (env->log.level > 1) + for (i = 0; i < env->subprog_cnt; i++) + verbose(env, "func#%d @%d\n", i, env->subprog_starts[i]); + + /* now check that all jumps are within the same subprog */ + subprog_start = 0; + if (env->subprog_cnt == cur_subprog) + subprog_end = insn_cnt; + else + subprog_end = env->subprog_starts[cur_subprog++]; + for (i = 0; i < insn_cnt; i++) { + u8 code = insn[i].code; + + if (BPF_CLASS(code) != BPF_JMP) + goto next; + if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL) + goto next; + off = i + insn[i].off + 1; + if (off < subprog_start || off >= subprog_end) { + verbose(env, "jump out of range from insn %d to %d\n", i, off); + return -EINVAL; + } +next: + if (i == subprog_end - 1) { + /* to avoid fall-through from one subprog into another + * the last insn of the subprog should be either exit + * or unconditional jump back + */ + if (code != (BPF_JMP | BPF_EXIT) && + code != (BPF_JMP | BPF_JA)) { + verbose(env, "last insn is not an exit or jmp\n"); + return -EINVAL; + } + subprog_start = subprog_end; + if (env->subprog_cnt == cur_subprog) + subprog_end = insn_cnt; + else + subprog_end = env->subprog_starts[cur_subprog++]; + } + } + return 0; +} + +static +struct bpf_verifier_state *skip_callee(struct bpf_verifier_env *env, + const struct bpf_verifier_state *state, + struct bpf_verifier_state *parent, + u32 regno) +{ + struct bpf_verifier_state *tmp = NULL; + + /* 'parent' could be a state of caller and + * 'state' could be a state of callee. In such case + * parent->curframe < state->curframe + * and it's ok for r1 - r5 registers + * + * 'parent' could be a callee's state after it bpf_exit-ed. + * In such case parent->curframe > state->curframe + * and it's ok for r0 only + */ + if (parent->curframe == state->curframe || + (parent->curframe < state->curframe && + regno >= BPF_REG_1 && regno <= BPF_REG_5) || + (parent->curframe > state->curframe && + regno == BPF_REG_0)) + return parent; + + if (parent->curframe > state->curframe && + regno >= BPF_REG_6) { + /* for callee saved regs we have to skip the whole chain + * of states that belong to callee and mark as LIVE_READ + * the registers before the call + */ + tmp = parent; + while (tmp && tmp->curframe != state->curframe) { + tmp = tmp->parent; + } + if (!tmp) + goto bug; + parent = tmp; + } else { + goto bug; + } + return parent; +bug: + verbose(env, "verifier bug regno %d tmp %p\n", regno, tmp); + verbose(env, "regno %d parent frame %d current frame %d\n", + regno, parent->curframe, state->curframe); + return NULL; +} + +static int mark_reg_read(struct bpf_verifier_env *env, + const struct bpf_verifier_state *state, + struct bpf_verifier_state *parent, + u32 regno) +{ + bool writes = parent == state->parent; /* Observe write marks */ if (regno == BPF_REG_FP) /* We don't need to worry about FP liveness because it's read-only */ - return; + return 0; while (parent) { /* if read wasn't screened by an earlier write ... */ - if (state->regs[regno].live & REG_LIVE_WRITTEN) + if (writes && state->frame[state->curframe]->regs[regno].live & REG_LIVE_WRITTEN) break; + parent = skip_callee(env, state, parent, regno); + if (!parent) + return -EFAULT; /* ... then we depend on parent's value */ - parent->regs[regno].live |= REG_LIVE_READ; + parent->frame[parent->curframe]->regs[regno].live |= REG_LIVE_READ; state = parent; parent = state->parent; + writes = true; } + return 0; } static int check_reg_arg(struct bpf_verifier_env *env, u32 regno, enum reg_arg_type t) { - struct bpf_reg_state *regs = env->cur_state->regs; + struct bpf_verifier_state *vstate = env->cur_state; + struct bpf_func_state *state = vstate->frame[vstate->curframe]; + struct bpf_reg_state *regs = state->regs; if (regno >= MAX_BPF_REG) { verbose(env, "R%d is invalid\n", regno); @@ -655,7 +928,7 @@ static int check_reg_arg(struct bpf_verifier_env *env, u32 regno, verbose(env, "R%d !read_ok\n", regno); return -EACCES; } - mark_reg_read(env->cur_state, regno); + return mark_reg_read(env, vstate, vstate->parent, regno); } else { /* check whether register used as dest operand can be written to */ if (regno == BPF_REG_FP) { @@ -686,17 +959,25 @@ static bool is_spillable_regtype(enum bpf_reg_type type) } } +/* Does this register contain a constant zero? */ +static bool register_is_null(struct bpf_reg_state *reg) +{ + return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0); +} + /* check_stack_read/write functions track spill/fill of registers, * stack boundary and alignment are checked in check_mem_access() */ static int check_stack_write(struct bpf_verifier_env *env, - struct bpf_verifier_state *state, int off, - int size, int value_regno) + struct bpf_func_state *state, /* func where register points to */ + int off, int size, int value_regno) { + struct bpf_func_state *cur; /* state of the current function */ int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err; + enum bpf_reg_type type; - err = realloc_verifier_state(state, round_up(slot + 1, BPF_REG_SIZE), - true); + err = realloc_func_state(state, round_up(slot + 1, BPF_REG_SIZE), + true); if (err) return err; /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0, @@ -709,8 +990,9 @@ static int check_stack_write(struct bpf_verifier_env *env, return -EACCES; } + cur = env->cur_state->frame[env->cur_state->curframe]; if (value_regno >= 0 && - is_spillable_regtype(state->regs[value_regno].type)) { + is_spillable_regtype((type = cur->regs[value_regno].type))) { /* register containing pointer is being spilled into stack */ if (size != BPF_REG_SIZE) { @@ -718,51 +1000,116 @@ static int check_stack_write(struct bpf_verifier_env *env, return -EACCES; } + if (state != cur && type == PTR_TO_STACK) { + verbose(env, "cannot spill pointers to stack into stack frame of the caller\n"); + return -EINVAL; + } + /* save register state */ - state->stack[spi].spilled_ptr = state->regs[value_regno]; + state->stack[spi].spilled_ptr = cur->regs[value_regno]; state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; for (i = 0; i < BPF_REG_SIZE; i++) state->stack[spi].slot_type[i] = STACK_SPILL; } else { + u8 type = STACK_MISC; + /* regular write of data into stack */ state->stack[spi].spilled_ptr = (struct bpf_reg_state) {}; + /* only mark the slot as written if all 8 bytes were written + * otherwise read propagation may incorrectly stop too soon + * when stack slots are partially written. + * This heuristic means that read propagation will be + * conservative, since it will add reg_live_read marks + * to stack slots all the way to first state when programs + * writes+reads less than 8 bytes + */ + if (size == BPF_REG_SIZE) + state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; + + /* when we zero initialize stack slots mark them as such */ + if (value_regno >= 0 && + register_is_null(&cur->regs[value_regno])) + type = STACK_ZERO; + for (i = 0; i < size; i++) state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] = - STACK_MISC; + type; } return 0; } -static void mark_stack_slot_read(const struct bpf_verifier_state *state, int slot) +/* registers of every function are unique and mark_reg_read() propagates + * the liveness in the following cases: + * - from callee into caller for R1 - R5 that were used as arguments + * - from caller into callee for R0 that used as result of the call + * - from caller to the same caller skipping states of the callee for R6 - R9, + * since R6 - R9 are callee saved by implicit function prologue and + * caller's R6 != callee's R6, so when we propagate liveness up to + * parent states we need to skip callee states for R6 - R9. + * + * stack slot marking is different, since stacks of caller and callee are + * accessible in both (since caller can pass a pointer to caller's stack to + * callee which can pass it to another function), hence mark_stack_slot_read() + * has to propagate the stack liveness to all parent states at given frame number. + * Consider code: + * f1() { + * ptr = fp - 8; + * *ptr = ctx; + * call f2 { + * .. = *ptr; + * } + * .. = *ptr; + * } + * First *ptr is reading from f1's stack and mark_stack_slot_read() has + * to mark liveness at the f1's frame and not f2's frame. + * Second *ptr is also reading from f1's stack and mark_stack_slot_read() has + * to propagate liveness to f2 states at f1's frame level and further into + * f1 states at f1's frame level until write into that stack slot + */ +static void mark_stack_slot_read(struct bpf_verifier_env *env, + const struct bpf_verifier_state *state, + struct bpf_verifier_state *parent, + int slot, int frameno) { - struct bpf_verifier_state *parent = state->parent; + bool writes = parent == state->parent; /* Observe write marks */ while (parent) { + if (parent->frame[frameno]->allocated_stack <= slot * BPF_REG_SIZE) + /* since LIVE_WRITTEN mark is only done for full 8-byte + * write the read marks are conservative and parent + * state may not even have the stack allocated. In such case + * end the propagation, since the loop reached beginning + * of the function + */ + break; /* if read wasn't screened by an earlier write ... */ - if (state->stack[slot].spilled_ptr.live & REG_LIVE_WRITTEN) + if (writes && state->frame[frameno]->stack[slot].spilled_ptr.live & REG_LIVE_WRITTEN) break; /* ... then we depend on parent's value */ - parent->stack[slot].spilled_ptr.live |= REG_LIVE_READ; + parent->frame[frameno]->stack[slot].spilled_ptr.live |= REG_LIVE_READ; state = parent; parent = state->parent; + writes = true; } } static int check_stack_read(struct bpf_verifier_env *env, - struct bpf_verifier_state *state, int off, int size, - int value_regno) + struct bpf_func_state *reg_state /* func where register points to */, + int off, int size, int value_regno) { + struct bpf_verifier_state *vstate = env->cur_state; + struct bpf_func_state *state = vstate->frame[vstate->curframe]; int i, slot = -off - 1, spi = slot / BPF_REG_SIZE; u8 *stype; - if (state->allocated_stack <= slot) { + if (reg_state->allocated_stack <= slot) { verbose(env, "invalid read from stack off %d+0 size %d\n", off, size); return -EACCES; } - stype = state->stack[spi].slot_type; + stype = reg_state->stack[spi].slot_type; if (stype[0] == STACK_SPILL) { if (size != BPF_REG_SIZE) { @@ -778,21 +1125,44 @@ static int check_stack_read(struct bpf_verifier_env *env, if (value_regno >= 0) { /* restore register state from stack */ - state->regs[value_regno] = state->stack[spi].spilled_ptr; - mark_stack_slot_read(state, spi); + state->regs[value_regno] = reg_state->stack[spi].spilled_ptr; + /* mark reg as written since spilled pointer state likely + * has its liveness marks cleared by is_state_visited() + * which resets stack/reg liveness for state transitions + */ + state->regs[value_regno].live |= REG_LIVE_WRITTEN; } + mark_stack_slot_read(env, vstate, vstate->parent, spi, + reg_state->frameno); return 0; } else { + int zeros = 0; + for (i = 0; i < size; i++) { - if (stype[(slot - i) % BPF_REG_SIZE] != STACK_MISC) { - verbose(env, "invalid read from stack off %d+%d size %d\n", - off, i, size); - return -EACCES; + if (stype[(slot - i) % BPF_REG_SIZE] == STACK_MISC) + continue; + if (stype[(slot - i) % BPF_REG_SIZE] == STACK_ZERO) { + zeros++; + continue; + } + verbose(env, "invalid read from stack off %d+%d size %d\n", + off, i, size); + return -EACCES; + } + mark_stack_slot_read(env, vstate, vstate->parent, spi, + reg_state->frameno); + if (value_regno >= 0) { + if (zeros == size) { + /* any size read into register is zero extended, + * so the whole register == const_zero + */ + __mark_reg_const_zero(&state->regs[value_regno]); + } else { + /* have read misc data from the stack */ + mark_reg_unknown(env, state->regs, value_regno); } + state->regs[value_regno].live |= REG_LIVE_WRITTEN; } - if (value_regno >= 0) - /* have read misc data from the stack */ - mark_reg_unknown(env, state->regs, value_regno); return 0; } } @@ -817,7 +1187,8 @@ static int __check_map_access(struct bpf_verifier_env *env, u32 regno, int off, static int check_map_access(struct bpf_verifier_env *env, u32 regno, int off, int size, bool zero_size_allowed) { - struct bpf_verifier_state *state = env->cur_state; + struct bpf_verifier_state *vstate = env->cur_state; + struct bpf_func_state *state = vstate->frame[vstate->curframe]; struct bpf_reg_state *reg = &state->regs[regno]; int err; @@ -1079,6 +1450,103 @@ static int check_ptr_alignment(struct bpf_verifier_env *env, strict); } +static int update_stack_depth(struct bpf_verifier_env *env, + const struct bpf_func_state *func, + int off) +{ + u16 stack = env->subprog_stack_depth[func->subprogno]; + + if (stack >= -off) + return 0; + + /* update known max for given subprogram */ + env->subprog_stack_depth[func->subprogno] = -off; + return 0; +} + +/* starting from main bpf function walk all instructions of the function + * and recursively walk all callees that given function can call. + * Ignore jump and exit insns. + * Since recursion is prevented by check_cfg() this algorithm + * only needs a local stack of MAX_CALL_FRAMES to remember callsites + */ +static int check_max_stack_depth(struct bpf_verifier_env *env) +{ + int depth = 0, frame = 0, subprog = 0, i = 0, subprog_end; + struct bpf_insn *insn = env->prog->insnsi; + int insn_cnt = env->prog->len; + int ret_insn[MAX_CALL_FRAMES]; + int ret_prog[MAX_CALL_FRAMES]; + +process_func: + /* round up to 32-bytes, since this is granularity + * of interpreter stack size + */ + depth += round_up(max_t(u32, env->subprog_stack_depth[subprog], 1), 32); + if (depth > MAX_BPF_STACK) { + verbose(env, "combined stack size of %d calls is %d. Too large\n", + frame + 1, depth); + return -EACCES; + } +continue_func: + if (env->subprog_cnt == subprog) + subprog_end = insn_cnt; + else + subprog_end = env->subprog_starts[subprog]; + for (; i < subprog_end; i++) { + if (insn[i].code != (BPF_JMP | BPF_CALL)) + continue; + if (insn[i].src_reg != BPF_PSEUDO_CALL) + continue; + /* remember insn and function to return to */ + ret_insn[frame] = i + 1; + ret_prog[frame] = subprog; + + /* find the callee */ + i = i + insn[i].imm + 1; + subprog = find_subprog(env, i); + if (subprog < 0) { + WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", + i); + return -EFAULT; + } + subprog++; + frame++; + if (frame >= MAX_CALL_FRAMES) { + WARN_ONCE(1, "verifier bug. Call stack is too deep\n"); + return -EFAULT; + } + goto process_func; + } + /* end of for() loop means the last insn of the 'subprog' + * was reached. Doesn't matter whether it was JA or EXIT + */ + if (frame == 0) + return 0; + depth -= round_up(max_t(u32, env->subprog_stack_depth[subprog], 1), 32); + frame--; + i = ret_insn[frame]; + subprog = ret_prog[frame]; + goto continue_func; +} + +#ifndef CONFIG_BPF_JIT_ALWAYS_ON +static int get_callee_stack_depth(struct bpf_verifier_env *env, + const struct bpf_insn *insn, int idx) +{ + int start = idx + insn->imm + 1, subprog; + + subprog = find_subprog(env, start); + if (subprog < 0) { + WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", + start); + return -EFAULT; + } + subprog++; + return env->subprog_stack_depth[subprog]; +} +#endif + /* truncate register to smaller size (in bytes) * must be called with size < BPF_REG_SIZE */ @@ -1112,9 +1580,9 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn int bpf_size, enum bpf_access_type t, int value_regno) { - struct bpf_verifier_state *state = env->cur_state; struct bpf_reg_state *regs = cur_regs(env); struct bpf_reg_state *reg = regs + regno; + struct bpf_func_state *state; int size, err = 0; size = bpf_size_to_bytes(bpf_size); @@ -1203,8 +1671,10 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn return -EACCES; } - if (env->prog->aux->stack_depth < -off) - env->prog->aux->stack_depth = -off; + state = func(env, reg); + err = update_stack_depth(env, state, off); + if (err) + return err; if (t == BPF_WRITE) err = check_stack_write(env, state, off, size, @@ -1282,12 +1752,6 @@ static int check_xadd(struct bpf_verifier_env *env, int insn_idx, struct bpf_ins BPF_SIZE(insn->code), BPF_WRITE, -1); } -/* Does this register contain a constant zero? */ -static bool register_is_null(struct bpf_reg_state reg) -{ - return reg.type == SCALAR_VALUE && tnum_equals_const(reg.var_off, 0); -} - /* when register 'regno' is passed into function that will read 'access_size' * bytes from that pointer, make sure that it's within stack boundary * and all elements of stack are initialized. @@ -1298,32 +1762,32 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, int access_size, bool zero_size_allowed, struct bpf_call_arg_meta *meta) { - struct bpf_verifier_state *state = env->cur_state; - struct bpf_reg_state *regs = state->regs; + struct bpf_reg_state *reg = cur_regs(env) + regno; + struct bpf_func_state *state = func(env, reg); int off, i, slot, spi; - if (regs[regno].type != PTR_TO_STACK) { + if (reg->type != PTR_TO_STACK) { /* Allow zero-byte read from NULL, regardless of pointer type */ if (zero_size_allowed && access_size == 0 && - register_is_null(regs[regno])) + register_is_null(reg)) return 0; verbose(env, "R%d type=%s expected=%s\n", regno, - reg_type_str[regs[regno].type], + reg_type_str[reg->type], reg_type_str[PTR_TO_STACK]); return -EACCES; } /* Only allow fixed-offset stack reads */ - if (!tnum_is_const(regs[regno].var_off)) { + if (!tnum_is_const(reg->var_off)) { char tn_buf[48]; - tnum_strn(tn_buf, sizeof(tn_buf), regs[regno].var_off); + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); verbose(env, "invalid variable stack read R%d var_off=%s\n", regno, tn_buf); return -EACCES; } - off = regs[regno].off + regs[regno].var_off.value; + off = reg->off + reg->var_off.value; if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 || access_size < 0 || (access_size == 0 && !zero_size_allowed)) { verbose(env, "invalid stack type R%d off=%d access_size=%d\n", @@ -1331,9 +1795,6 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, return -EACCES; } - if (env->prog->aux->stack_depth < -off) - env->prog->aux->stack_depth = -off; - if (meta && meta->raw_mode) { meta->access_size = access_size; meta->regno = regno; @@ -1341,17 +1802,32 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, } for (i = 0; i < access_size; i++) { + u8 *stype; + slot = -(off + i) - 1; spi = slot / BPF_REG_SIZE; - if (state->allocated_stack <= slot || - state->stack[spi].slot_type[slot % BPF_REG_SIZE] != - STACK_MISC) { - verbose(env, "invalid indirect read from stack off %d+%d size %d\n", - off, i, access_size); - return -EACCES; + if (state->allocated_stack <= slot) + goto err; + stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE]; + if (*stype == STACK_MISC) + goto mark; + if (*stype == STACK_ZERO) { + /* helper can write anything into the stack */ + *stype = STACK_MISC; + goto mark; } +err: + verbose(env, "invalid indirect read from stack off %d+%d size %d\n", + off, i, access_size); + return -EACCES; +mark: + /* reading any byte out of 8-byte 'spill_slot' will cause + * the whole slot to be marked as 'read' + */ + mark_stack_slot_read(env, env->cur_state, env->cur_state->parent, + spi, state->frameno); } - return 0; + return update_stack_depth(env, state, off); } static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, @@ -1374,6 +1850,19 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, } } +static bool arg_type_is_mem_ptr(enum bpf_arg_type type) +{ + return type == ARG_PTR_TO_MEM || + type == ARG_PTR_TO_MEM_OR_NULL || + type == ARG_PTR_TO_UNINIT_MEM; +} + +static bool arg_type_is_mem_size(enum bpf_arg_type type) +{ + return type == ARG_CONST_SIZE || + type == ARG_CONST_SIZE_OR_ZERO; +} + static int check_func_arg(struct bpf_verifier_env *env, u32 regno, enum bpf_arg_type arg_type, struct bpf_call_arg_meta *meta) @@ -1423,15 +1912,13 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, expected_type = PTR_TO_CTX; if (type != expected_type) goto err_type; - } else if (arg_type == ARG_PTR_TO_MEM || - arg_type == ARG_PTR_TO_MEM_OR_NULL || - arg_type == ARG_PTR_TO_UNINIT_MEM) { + } else if (arg_type_is_mem_ptr(arg_type)) { expected_type = PTR_TO_STACK; /* One exception here. In case function allows for NULL to be * passed in as argument, it's a SCALAR_VALUE type. Final test * happens during stack boundary checking. */ - if (register_is_null(*reg) && + if (register_is_null(reg) && arg_type == ARG_PTR_TO_MEM_OR_NULL) /* final test in check_stack_boundary() */; else if (!type_is_pkt_pointer(type) && @@ -1486,25 +1973,12 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, err = check_stack_boundary(env, regno, meta->map_ptr->value_size, false, NULL); - } else if (arg_type == ARG_CONST_SIZE || - arg_type == ARG_CONST_SIZE_OR_ZERO) { + } else if (arg_type_is_mem_size(arg_type)) { bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); - /* bpf_xxx(..., buf, len) call will access 'len' bytes - * from stack pointer 'buf'. Check it - * note: regno == len, regno - 1 == buf - */ - if (regno == 0) { - /* kernel subsystem misconfigured verifier */ - verbose(env, - "ARG_CONST_SIZE cannot be first argument\n"); - return -EACCES; - } - /* The register is SCALAR_VALUE; the access check * happens using its boundaries. */ - if (!tnum_is_const(reg->var_off)) /* For unprivileged variable accesses, disable raw * mode so that the program is required to @@ -1604,6 +2078,10 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, case BPF_FUNC_tail_call: if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) goto error; + if (env->subprog_cnt) { + verbose(env, "tail_calls are not allowed in programs with bpf-to-bpf calls\n"); + return -EINVAL; + } break; case BPF_FUNC_perf_event_read: case BPF_FUNC_perf_event_output: @@ -1644,7 +2122,7 @@ error: return -EINVAL; } -static int check_raw_mode(const struct bpf_func_proto *fn) +static bool check_raw_mode_ok(const struct bpf_func_proto *fn) { int count = 0; @@ -1659,15 +2137,52 @@ static int check_raw_mode(const struct bpf_func_proto *fn) if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM) count++; - return count > 1 ? -EINVAL : 0; + /* We only support one arg being in raw mode at the moment, + * which is sufficient for the helper functions we have + * right now. + */ + return count <= 1; +} + +static bool check_args_pair_invalid(enum bpf_arg_type arg_curr, + enum bpf_arg_type arg_next) +{ + return (arg_type_is_mem_ptr(arg_curr) && + !arg_type_is_mem_size(arg_next)) || + (!arg_type_is_mem_ptr(arg_curr) && + arg_type_is_mem_size(arg_next)); +} + +static bool check_arg_pair_ok(const struct bpf_func_proto *fn) +{ + /* bpf_xxx(..., buf, len) call will access 'len' + * bytes from memory 'buf'. Both arg types need + * to be paired, so make sure there's no buggy + * helper function specification. + */ + if (arg_type_is_mem_size(fn->arg1_type) || + arg_type_is_mem_ptr(fn->arg5_type) || + check_args_pair_invalid(fn->arg1_type, fn->arg2_type) || + check_args_pair_invalid(fn->arg2_type, fn->arg3_type) || + check_args_pair_invalid(fn->arg3_type, fn->arg4_type) || + check_args_pair_invalid(fn->arg4_type, fn->arg5_type)) + return false; + + return true; +} + +static int check_func_proto(const struct bpf_func_proto *fn) +{ + return check_raw_mode_ok(fn) && + check_arg_pair_ok(fn) ? 0 : -EINVAL; } /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END] * are now invalid, so turn them into unknown SCALAR_VALUE. */ -static void clear_all_pkt_pointers(struct bpf_verifier_env *env) +static void __clear_all_pkt_pointers(struct bpf_verifier_env *env, + struct bpf_func_state *state) { - struct bpf_verifier_state *state = env->cur_state; struct bpf_reg_state *regs = state->regs, *reg; int i; @@ -1684,7 +2199,121 @@ static void clear_all_pkt_pointers(struct bpf_verifier_env *env) } } -static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) +static void clear_all_pkt_pointers(struct bpf_verifier_env *env) +{ + struct bpf_verifier_state *vstate = env->cur_state; + int i; + + for (i = 0; i <= vstate->curframe; i++) + __clear_all_pkt_pointers(env, vstate->frame[i]); +} + +static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, + int *insn_idx) +{ + struct bpf_verifier_state *state = env->cur_state; + struct bpf_func_state *caller, *callee; + int i, subprog, target_insn; + + if (state->curframe + 1 >= MAX_CALL_FRAMES) { + verbose(env, "the call stack of %d frames is too deep\n", + state->curframe + 2); + return -E2BIG; + } + + target_insn = *insn_idx + insn->imm; + subprog = find_subprog(env, target_insn + 1); + if (subprog < 0) { + verbose(env, "verifier bug. No program starts at insn %d\n", + target_insn + 1); + return -EFAULT; + } + + caller = state->frame[state->curframe]; + if (state->frame[state->curframe + 1]) { + verbose(env, "verifier bug. Frame %d already allocated\n", + state->curframe + 1); + return -EFAULT; + } + + callee = kzalloc(sizeof(*callee), GFP_KERNEL); + if (!callee) + return -ENOMEM; + state->frame[state->curframe + 1] = callee; + + /* callee cannot access r0, r6 - r9 for reading and has to write + * into its own stack before reading from it. + * callee can read/write into caller's stack + */ + init_func_state(env, callee, + /* remember the callsite, it will be used by bpf_exit */ + *insn_idx /* callsite */, + state->curframe + 1 /* frameno within this callchain */, + subprog + 1 /* subprog number within this prog */); + + /* copy r1 - r5 args that callee can access */ + for (i = BPF_REG_1; i <= BPF_REG_5; i++) + callee->regs[i] = caller->regs[i]; + + /* after the call regsiters r0 - r5 were scratched */ + for (i = 0; i < CALLER_SAVED_REGS; i++) { + mark_reg_not_init(env, caller->regs, caller_saved[i]); + check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK); + } + + /* only increment it after check_reg_arg() finished */ + state->curframe++; + + /* and go analyze first insn of the callee */ + *insn_idx = target_insn; + + if (env->log.level) { + verbose(env, "caller:\n"); + print_verifier_state(env, caller); + verbose(env, "callee:\n"); + print_verifier_state(env, callee); + } + return 0; +} + +static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) +{ + struct bpf_verifier_state *state = env->cur_state; + struct bpf_func_state *caller, *callee; + struct bpf_reg_state *r0; + + callee = state->frame[state->curframe]; + r0 = &callee->regs[BPF_REG_0]; + if (r0->type == PTR_TO_STACK) { + /* technically it's ok to return caller's stack pointer + * (or caller's caller's pointer) back to the caller, + * since these pointers are valid. Only current stack + * pointer will be invalid as soon as function exits, + * but let's be conservative + */ + verbose(env, "cannot return stack pointer to the caller\n"); + return -EINVAL; + } + + state->curframe--; + caller = state->frame[state->curframe]; + /* return to the caller whatever r0 had in the callee */ + caller->regs[BPF_REG_0] = *r0; + + *insn_idx = callee->callsite + 1; + if (env->log.level) { + verbose(env, "returning from callee:\n"); + print_verifier_state(env, callee); + verbose(env, "to caller at %d:\n", *insn_idx); + print_verifier_state(env, caller); + } + /* clear everything in the callee */ + free_func_state(callee); + state->frame[state->curframe + 1] = NULL; + return 0; +} + +static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx) { const struct bpf_func_proto *fn = NULL; struct bpf_reg_state *regs; @@ -1701,7 +2330,6 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) if (env->ops->get_func_proto) fn = env->ops->get_func_proto(func_id); - if (!fn) { verbose(env, "unknown func %s#%d\n", func_id_name(func_id), func_id); @@ -1725,10 +2353,7 @@ static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) memset(&meta, 0, sizeof(meta)); meta.pkt_access = fn->pkt_access; - /* We only support one arg being in raw mode at the moment, which - * is sufficient for the helper functions we have right now. - */ - err = check_raw_mode(fn); + err = check_func_proto(fn); if (err) { verbose(env, "kernel subsystem misconfigured func %s#%d\n", func_id_name(func_id), func_id); @@ -1884,7 +2509,9 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, const struct bpf_reg_state *ptr_reg, const struct bpf_reg_state *off_reg) { - struct bpf_reg_state *regs = cur_regs(env), *dst_reg; + struct bpf_verifier_state *vstate = env->cur_state; + struct bpf_func_state *state = vstate->frame[vstate->curframe]; + struct bpf_reg_state *regs = state->regs, *dst_reg; bool known = tnum_is_const(off_reg->var_off); s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value, smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value; @@ -2319,7 +2946,9 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, struct bpf_insn *insn) { - struct bpf_reg_state *regs = cur_regs(env), *dst_reg, *src_reg; + struct bpf_verifier_state *vstate = env->cur_state; + struct bpf_func_state *state = vstate->frame[vstate->curframe]; + struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg; struct bpf_reg_state *ptr_reg = NULL, off_reg = {0}; u8 opcode = BPF_OP(insn->code); @@ -2370,12 +2999,12 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, /* Got here implies adding two SCALAR_VALUEs */ if (WARN_ON_ONCE(ptr_reg)) { - print_verifier_state(env, env->cur_state); + print_verifier_state(env, state); verbose(env, "verifier internal error: unexpected ptr_reg\n"); return -EINVAL; } if (WARN_ON(!src_reg)) { - print_verifier_state(env, env->cur_state); + print_verifier_state(env, state); verbose(env, "verifier internal error: no src_reg\n"); return -EINVAL; } @@ -2537,14 +3166,15 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) return 0; } -static void find_good_pkt_pointers(struct bpf_verifier_state *state, +static void find_good_pkt_pointers(struct bpf_verifier_state *vstate, struct bpf_reg_state *dst_reg, enum bpf_reg_type type, bool range_right_open) { + struct bpf_func_state *state = vstate->frame[vstate->curframe]; struct bpf_reg_state *regs = state->regs, *reg; u16 new_range; - int i; + int i, j; if (dst_reg->off < 0 || (dst_reg->off == 0 && range_right_open)) @@ -2614,12 +3244,15 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state, /* keep the maximum range already checked */ regs[i].range = max(regs[i].range, new_range); - for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { - if (state->stack[i].slot_type[0] != STACK_SPILL) - continue; - reg = &state->stack[i].spilled_ptr; - if (reg->type == type && reg->id == dst_reg->id) - reg->range = max(reg->range, new_range); + for (j = 0; j <= vstate->curframe; j++) { + state = vstate->frame[j]; + for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { + if (state->stack[i].slot_type[0] != STACK_SPILL) + continue; + reg = &state->stack[i].spilled_ptr; + if (reg->type == type && reg->id == dst_reg->id) + reg->range = max(reg->range, new_range); + } } } @@ -2857,20 +3490,24 @@ static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id, /* The logic is similar to find_good_pkt_pointers(), both could eventually * be folded together at some point. */ -static void mark_map_regs(struct bpf_verifier_state *state, u32 regno, +static void mark_map_regs(struct bpf_verifier_state *vstate, u32 regno, bool is_null) { + struct bpf_func_state *state = vstate->frame[vstate->curframe]; struct bpf_reg_state *regs = state->regs; u32 id = regs[regno].id; - int i; + int i, j; for (i = 0; i < MAX_BPF_REG; i++) mark_map_reg(regs, i, id, is_null); - for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { - if (state->stack[i].slot_type[0] != STACK_SPILL) - continue; - mark_map_reg(&state->stack[i].spilled_ptr, 0, id, is_null); + for (j = 0; j <= vstate->curframe; j++) { + state = vstate->frame[j]; + for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) { + if (state->stack[i].slot_type[0] != STACK_SPILL) + continue; + mark_map_reg(&state->stack[i].spilled_ptr, 0, id, is_null); + } } } @@ -2970,8 +3607,10 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn, static int check_cond_jmp_op(struct bpf_verifier_env *env, struct bpf_insn *insn, int *insn_idx) { - struct bpf_verifier_state *other_branch, *this_branch = env->cur_state; - struct bpf_reg_state *regs = this_branch->regs, *dst_reg; + struct bpf_verifier_state *this_branch = env->cur_state; + struct bpf_verifier_state *other_branch; + struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs; + struct bpf_reg_state *dst_reg, *other_branch_regs; u8 opcode = BPF_OP(insn->code); int err; @@ -3014,8 +3653,9 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, if (BPF_SRC(insn->code) == BPF_K && (opcode == BPF_JEQ || opcode == BPF_JNE) && dst_reg->type == SCALAR_VALUE && - tnum_equals_const(dst_reg->var_off, insn->imm)) { - if (opcode == BPF_JEQ) { + tnum_is_const(dst_reg->var_off)) { + if ((opcode == BPF_JEQ && dst_reg->var_off.value == insn->imm) || + (opcode == BPF_JNE && dst_reg->var_off.value != insn->imm)) { /* if (imm == imm) goto pc+off; * only follow the goto, ignore fall-through */ @@ -3033,6 +3673,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx); if (!other_branch) return -EFAULT; + other_branch_regs = other_branch->frame[other_branch->curframe]->regs; /* detect if we are comparing against a constant value so we can adjust * our min/max values for our dst register. @@ -3045,22 +3686,22 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, if (dst_reg->type == SCALAR_VALUE && regs[insn->src_reg].type == SCALAR_VALUE) { if (tnum_is_const(regs[insn->src_reg].var_off)) - reg_set_min_max(&other_branch->regs[insn->dst_reg], + reg_set_min_max(&other_branch_regs[insn->dst_reg], dst_reg, regs[insn->src_reg].var_off.value, opcode); else if (tnum_is_const(dst_reg->var_off)) - reg_set_min_max_inv(&other_branch->regs[insn->src_reg], + reg_set_min_max_inv(&other_branch_regs[insn->src_reg], ®s[insn->src_reg], dst_reg->var_off.value, opcode); else if (opcode == BPF_JEQ || opcode == BPF_JNE) /* Comparing for equality, we can combine knowledge */ - reg_combine_min_max(&other_branch->regs[insn->src_reg], - &other_branch->regs[insn->dst_reg], + reg_combine_min_max(&other_branch_regs[insn->src_reg], + &other_branch_regs[insn->dst_reg], ®s[insn->src_reg], ®s[insn->dst_reg], opcode); } } else if (dst_reg->type == SCALAR_VALUE) { - reg_set_min_max(&other_branch->regs[insn->dst_reg], + reg_set_min_max(&other_branch_regs[insn->dst_reg], dst_reg, insn->imm, opcode); } @@ -3081,7 +3722,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, return -EACCES; } if (env->log.level) - print_verifier_state(env, this_branch); + print_verifier_state(env, this_branch->frame[this_branch->curframe]); return 0; } @@ -3166,6 +3807,18 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) return -EINVAL; } + if (env->subprog_cnt) { + /* when program has LD_ABS insn JITs and interpreter assume + * that r1 == ctx == skb which is not the case for callees + * that can have arbitrary arguments. It's problematic + * for main prog as well since JITs would need to analyze + * all functions in order to make proper register save/restore + * decisions in the main prog. Hence disallow LD_ABS with calls + */ + verbose(env, "BPF_LD_[ABS|IND] instructions cannot be mixed with bpf-to-bpf calls\n"); + return -EINVAL; + } + if (insn->dst_reg != BPF_REG_0 || insn->off != 0 || BPF_SIZE(insn->code) == BPF_DW || (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) { @@ -3342,6 +3995,10 @@ static int check_cfg(struct bpf_verifier_env *env) int ret = 0; int i, t; + ret = check_subprogs(env); + if (ret < 0) + return ret; + insn_state = kcalloc(insn_cnt, sizeof(int), GFP_KERNEL); if (!insn_state) return -ENOMEM; @@ -3374,6 +4031,14 @@ peek_stack: goto err_free; if (t + 1 < insn_cnt) env->explored_states[t + 1] = STATE_LIST_MARK; + if (insns[t].src_reg == BPF_PSEUDO_CALL) { + env->explored_states[t] = STATE_LIST_MARK; + ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env); + if (ret == 1) + goto peek_stack; + else if (ret < 0) + goto err_free; + } } else if (opcode == BPF_JA) { if (BPF_SRC(insns[t].code) != BPF_K) { ret = -EINVAL; @@ -3492,11 +4157,21 @@ static bool check_ids(u32 old_id, u32 cur_id, struct idpair *idmap) static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, struct idpair *idmap) { + bool equal; + if (!(rold->live & REG_LIVE_READ)) /* explored state didn't use this */ return true; - if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, live)) == 0) + equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, frameno)) == 0; + + if (rold->type == PTR_TO_STACK) + /* two stack pointers are equal only if they're pointing to + * the same stack frame, since fp-8 in foo != fp-8 in bar + */ + return equal && rold->frameno == rcur->frameno; + + if (equal) return true; if (rold->type == NOT_INIT) @@ -3568,7 +4243,6 @@ static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, tnum_in(rold->var_off, rcur->var_off); case PTR_TO_CTX: case CONST_PTR_TO_MAP: - case PTR_TO_STACK: case PTR_TO_PACKET_END: /* Only valid matches are exact, which memcmp() above * would have accepted @@ -3583,8 +4257,8 @@ static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, return false; } -static bool stacksafe(struct bpf_verifier_state *old, - struct bpf_verifier_state *cur, +static bool stacksafe(struct bpf_func_state *old, + struct bpf_func_state *cur, struct idpair *idmap) { int i, spi; @@ -3602,8 +4276,19 @@ static bool stacksafe(struct bpf_verifier_state *old, for (i = 0; i < old->allocated_stack; i++) { spi = i / BPF_REG_SIZE; + if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) + /* explored state didn't use this */ + continue; + if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID) continue; + /* if old state was safe with misc data in the stack + * it will be safe with zero-initialized stack. + * The opposite is not true + */ + if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC && + cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO) + continue; if (old->stack[spi].slot_type[i % BPF_REG_SIZE] != cur->stack[spi].slot_type[i % BPF_REG_SIZE]) /* Ex: old explored (safe) state has STACK_SPILL in @@ -3660,9 +4345,8 @@ static bool stacksafe(struct bpf_verifier_state *old, * whereas register type in current state is meaningful, it means that * the current state will reach 'bpf_exit' instruction safely */ -static bool states_equal(struct bpf_verifier_env *env, - struct bpf_verifier_state *old, - struct bpf_verifier_state *cur) +static bool func_states_equal(struct bpf_func_state *old, + struct bpf_func_state *cur) { struct idpair *idmap; bool ret = false; @@ -3686,71 +4370,72 @@ out_free: return ret; } +static bool states_equal(struct bpf_verifier_env *env, + struct bpf_verifier_state *old, + struct bpf_verifier_state *cur) +{ + int i; + + if (old->curframe != cur->curframe) + return false; + + /* for states to be equal callsites have to be the same + * and all frame states need to be equivalent + */ + for (i = 0; i <= old->curframe; i++) { + if (old->frame[i]->callsite != cur->frame[i]->callsite) + return false; + if (!func_states_equal(old->frame[i], cur->frame[i])) + return false; + } + return true; +} + /* A write screens off any subsequent reads; but write marks come from the - * straight-line code between a state and its parent. When we arrive at a - * jump target (in the first iteration of the propagate_liveness() loop), - * we didn't arrive by the straight-line code, so read marks in state must - * propagate to parent regardless of state's write marks. + * straight-line code between a state and its parent. When we arrive at an + * equivalent state (jump target or such) we didn't arrive by the straight-line + * code, so read marks in the state must propagate to the parent regardless + * of the state's write marks. That's what 'parent == state->parent' comparison + * in mark_reg_read() and mark_stack_slot_read() is for. */ -static bool do_propagate_liveness(const struct bpf_verifier_state *state, - struct bpf_verifier_state *parent) +static int propagate_liveness(struct bpf_verifier_env *env, + const struct bpf_verifier_state *vstate, + struct bpf_verifier_state *vparent) { - bool writes = parent == state->parent; /* Observe write marks */ - bool touched = false; /* any changes made? */ - int i; + int i, frame, err = 0; + struct bpf_func_state *state, *parent; - if (!parent) - return touched; + if (vparent->curframe != vstate->curframe) { + WARN(1, "propagate_live: parent frame %d current frame %d\n", + vparent->curframe, vstate->curframe); + return -EFAULT; + } /* Propagate read liveness of registers... */ BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG); /* We don't need to worry about FP liveness because it's read-only */ for (i = 0; i < BPF_REG_FP; i++) { - if (parent->regs[i].live & REG_LIVE_READ) + if (vparent->frame[vparent->curframe]->regs[i].live & REG_LIVE_READ) continue; - if (writes && (state->regs[i].live & REG_LIVE_WRITTEN)) - continue; - if (state->regs[i].live & REG_LIVE_READ) { - parent->regs[i].live |= REG_LIVE_READ; - touched = true; + if (vstate->frame[vstate->curframe]->regs[i].live & REG_LIVE_READ) { + err = mark_reg_read(env, vstate, vparent, i); + if (err) + return err; } } + /* ... and stack slots */ - for (i = 0; i < state->allocated_stack / BPF_REG_SIZE && - i < parent->allocated_stack / BPF_REG_SIZE; i++) { - if (parent->stack[i].slot_type[0] != STACK_SPILL) - continue; - if (state->stack[i].slot_type[0] != STACK_SPILL) - continue; - if (parent->stack[i].spilled_ptr.live & REG_LIVE_READ) - continue; - if (writes && - (state->stack[i].spilled_ptr.live & REG_LIVE_WRITTEN)) - continue; - if (state->stack[i].spilled_ptr.live & REG_LIVE_READ) { - parent->stack[i].spilled_ptr.live |= REG_LIVE_READ; - touched = true; + for (frame = 0; frame <= vstate->curframe; frame++) { + state = vstate->frame[frame]; + parent = vparent->frame[frame]; + for (i = 0; i < state->allocated_stack / BPF_REG_SIZE && + i < parent->allocated_stack / BPF_REG_SIZE; i++) { + if (parent->stack[i].spilled_ptr.live & REG_LIVE_READ) + continue; + if (state->stack[i].spilled_ptr.live & REG_LIVE_READ) + mark_stack_slot_read(env, vstate, vparent, i, frame); } } - return touched; -} - -/* "parent" is "a state from which we reach the current state", but initially - * it is not the state->parent (i.e. "the state whose straight-line code leads - * to the current state"), instead it is the state that happened to arrive at - * a (prunable) equivalent of the current state. See comment above - * do_propagate_liveness() for consequences of this. - * This function is just a more efficient way of calling mark_reg_read() or - * mark_stack_slot_read() on each reg in "parent" that is read in "state", - * though it requires that parent != state->parent in the call arguments. - */ -static void propagate_liveness(const struct bpf_verifier_state *state, - struct bpf_verifier_state *parent) -{ - while (do_propagate_liveness(state, parent)) { - /* Something changed, so we need to feed those changes onward */ - state = parent; - parent = state->parent; - } + return err; } static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) @@ -3758,7 +4443,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) struct bpf_verifier_state_list *new_sl; struct bpf_verifier_state_list *sl; struct bpf_verifier_state *cur = env->cur_state; - int i, err; + int i, j, err; sl = env->explored_states[insn_idx]; if (!sl) @@ -3779,7 +4464,9 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) * they'll be immediately forgotten as we're pruning * this state and will pop a new one. */ - propagate_liveness(&sl->state, cur); + err = propagate_liveness(env, &sl->state, cur); + if (err) + return err; return 1; } sl = sl->next; @@ -3787,9 +4474,10 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) /* there were no equivalent states, remember current one. * technically the current state is not proven to be safe yet, - * but it will either reach bpf_exit (which means it's safe) or - * it will be rejected. Since there are no loops, we won't be - * seeing this 'insn_idx' instruction again on the way to bpf_exit + * but it will either reach outer most bpf_exit (which means it's safe) + * or it will be rejected. Since there are no loops, we won't be + * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx) + * again on the way to bpf_exit */ new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL); if (!new_sl) @@ -3813,19 +4501,15 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) * explored_states can get read marks.) */ for (i = 0; i < BPF_REG_FP; i++) - cur->regs[i].live = REG_LIVE_NONE; - for (i = 0; i < cur->allocated_stack / BPF_REG_SIZE; i++) - if (cur->stack[i].slot_type[0] == STACK_SPILL) - cur->stack[i].spilled_ptr.live = REG_LIVE_NONE; - return 0; -} + cur->frame[cur->curframe]->regs[i].live = REG_LIVE_NONE; -static int ext_analyzer_insn_hook(struct bpf_verifier_env *env, - int insn_idx, int prev_insn_idx) -{ - if (env->dev_ops && env->dev_ops->insn_hook) - return env->dev_ops->insn_hook(env, insn_idx, prev_insn_idx); + /* all stack frames are accessible from callee, clear them all */ + for (j = 0; j <= cur->curframe; j++) { + struct bpf_func_state *frame = cur->frame[j]; + for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) + frame->stack[i].spilled_ptr.live = REG_LIVE_NONE; + } return 0; } @@ -3834,7 +4518,7 @@ static int do_check(struct bpf_verifier_env *env) struct bpf_verifier_state *state; struct bpf_insn *insns = env->prog->insnsi; struct bpf_reg_state *regs; - int insn_cnt = env->prog->len; + int insn_cnt = env->prog->len, i; int insn_idx, prev_insn_idx = 0; int insn_processed = 0; bool do_print_state = false; @@ -3842,9 +4526,18 @@ static int do_check(struct bpf_verifier_env *env) state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL); if (!state) return -ENOMEM; - env->cur_state = state; - init_reg_state(env, state->regs); + state->curframe = 0; state->parent = NULL; + state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL); + if (!state->frame[0]) { + kfree(state); + return -ENOMEM; + } + env->cur_state = state; + init_func_state(env, state->frame[0], + BPF_MAIN_FUNC /* callsite */, + 0 /* frameno */, + 0 /* subprogno, zero == main subprog */); insn_idx = 0; for (;;) { struct bpf_insn *insn; @@ -3891,19 +4584,25 @@ static int do_check(struct bpf_verifier_env *env) else verbose(env, "\nfrom %d to %d:", prev_insn_idx, insn_idx); - print_verifier_state(env, state); + print_verifier_state(env, state->frame[state->curframe]); do_print_state = false; } if (env->log.level) { + const struct bpf_insn_cbs cbs = { + .cb_print = verbose, + }; + verbose(env, "%d: ", insn_idx); - print_bpf_insn(verbose, env, insn, - env->allow_ptr_leaks); + print_bpf_insn(&cbs, env, insn, env->allow_ptr_leaks); } - err = ext_analyzer_insn_hook(env, insn_idx, prev_insn_idx); - if (err) - return err; + if (bpf_prog_is_dev_bound(env->prog->aux)) { + err = bpf_prog_offload_verify_insn(env, insn_idx, + prev_insn_idx); + if (err) + return err; + } regs = cur_regs(env); env->insn_aux_data[insn_idx].seen = true; @@ -4030,13 +4729,17 @@ static int do_check(struct bpf_verifier_env *env) if (opcode == BPF_CALL) { if (BPF_SRC(insn->code) != BPF_K || insn->off != 0 || - insn->src_reg != BPF_REG_0 || + (insn->src_reg != BPF_REG_0 && + insn->src_reg != BPF_PSEUDO_CALL) || insn->dst_reg != BPF_REG_0) { verbose(env, "BPF_CALL uses reserved fields\n"); return -EINVAL; } - err = check_call(env, insn->imm, insn_idx); + if (insn->src_reg == BPF_PSEUDO_CALL) + err = check_func_call(env, insn, &insn_idx); + else + err = check_helper_call(env, insn->imm, insn_idx); if (err) return err; @@ -4061,6 +4764,16 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; } + if (state->curframe) { + /* exit from nested function */ + prev_insn_idx = insn_idx; + err = prepare_func_exit(env, &insn_idx); + if (err) + return err; + do_print_state = true; + continue; + } + /* eBPF calling convetion is such that R0 is used * to return the value from eBPF program. * Make sure that it's readable at this time @@ -4121,8 +4834,17 @@ process_bpf_exit: insn_idx++; } - verbose(env, "processed %d insns, stack depth %d\n", insn_processed, - env->prog->aux->stack_depth); + verbose(env, "processed %d insns (limit %d), stack depth ", + insn_processed, BPF_COMPLEXITY_LIMIT_INSNS); + for (i = 0; i < env->subprog_cnt + 1; i++) { + u32 depth = env->subprog_stack_depth[i]; + + verbose(env, "%d", depth); + if (i + 1 < env->subprog_cnt + 1) + verbose(env, "+"); + } + verbose(env, "\n"); + env->prog->aux->stack_depth = env->subprog_stack_depth[0]; return 0; } @@ -4155,6 +4877,13 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, return -EINVAL; } } + + if ((bpf_prog_is_dev_bound(prog->aux) || bpf_map_is_dev_bound(map)) && + !bpf_offload_dev_match(prog, map)) { + verbose(env, "offload device mismatch between prog and map\n"); + return -EINVAL; + } + return 0; } @@ -4252,6 +4981,13 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env) next_insn: insn++; i++; + continue; + } + + /* Basic sanity check before we invest more work here. */ + if (!bpf_opcode_in_insntable(insn->code)) { + verbose(env, "unknown opcode %02x\n", insn->code); + return -EINVAL; } } @@ -4308,6 +5044,19 @@ static int adjust_insn_aux_data(struct bpf_verifier_env *env, u32 prog_len, return 0; } +static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len) +{ + int i; + + if (len == 1) + return; + for (i = 0; i < env->subprog_cnt; i++) { + if (env->subprog_starts[i] < off) + continue; + env->subprog_starts[i] += len - 1; + } +} + static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off, const struct bpf_insn *patch, u32 len) { @@ -4318,17 +5067,25 @@ static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 of return NULL; if (adjust_insn_aux_data(env, new_prog->len, off, len)) return NULL; + adjust_subprog_starts(env, off, len); return new_prog; } -/* The verifier does more data flow analysis than llvm and will not explore - * branches that are dead at run time. Malicious programs can have dead code - * too. Therefore replace all dead at-run-time code with nops. +/* The verifier does more data flow analysis than llvm and will not + * explore branches that are dead at run time. Malicious programs can + * have dead code too. Therefore replace all dead at-run-time code + * with 'ja -1'. + * + * Just nops are not optimal, e.g. if they would sit at the end of the + * program and through another bug we would manage to jump there, then + * we'd execute beyond program memory otherwise. Returning exception + * code also wouldn't work since we can have subprogs where the dead + * code could be located. */ static void sanitize_dead_code(struct bpf_verifier_env *env) { struct bpf_insn_aux_data *aux_data = env->insn_aux_data; - struct bpf_insn nop = BPF_MOV64_REG(BPF_REG_0, BPF_REG_0); + struct bpf_insn trap = BPF_JMP_IMM(BPF_JA, 0, 0, -1); struct bpf_insn *insn = env->prog->insnsi; const int insn_cnt = env->prog->len; int i; @@ -4336,7 +5093,7 @@ static void sanitize_dead_code(struct bpf_verifier_env *env) for (i = 0; i < insn_cnt; i++) { if (aux_data[i].seen) continue; - memcpy(insn + i, &nop, sizeof(nop)); + memcpy(insn + i, &trap, sizeof(trap)); } } @@ -4452,6 +5209,180 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) return 0; } +static int jit_subprogs(struct bpf_verifier_env *env) +{ + struct bpf_prog *prog = env->prog, **func, *tmp; + int i, j, subprog_start, subprog_end = 0, len, subprog; + struct bpf_insn *insn; + void *old_bpf_func; + int err = -ENOMEM; + + if (env->subprog_cnt == 0) + return 0; + + for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { + if (insn->code != (BPF_JMP | BPF_CALL) || + insn->src_reg != BPF_PSEUDO_CALL) + continue; + subprog = find_subprog(env, i + insn->imm + 1); + if (subprog < 0) { + WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", + i + insn->imm + 1); + return -EFAULT; + } + /* temporarily remember subprog id inside insn instead of + * aux_data, since next loop will split up all insns into funcs + */ + insn->off = subprog + 1; + /* remember original imm in case JIT fails and fallback + * to interpreter will be needed + */ + env->insn_aux_data[i].call_imm = insn->imm; + /* point imm to __bpf_call_base+1 from JITs point of view */ + insn->imm = 1; + } + + func = kzalloc(sizeof(prog) * (env->subprog_cnt + 1), GFP_KERNEL); + if (!func) + return -ENOMEM; + + for (i = 0; i <= env->subprog_cnt; i++) { + subprog_start = subprog_end; + if (env->subprog_cnt == i) + subprog_end = prog->len; + else + subprog_end = env->subprog_starts[i]; + + len = subprog_end - subprog_start; + func[i] = bpf_prog_alloc(bpf_prog_size(len), GFP_USER); + if (!func[i]) + goto out_free; + memcpy(func[i]->insnsi, &prog->insnsi[subprog_start], + len * sizeof(struct bpf_insn)); + func[i]->type = prog->type; + func[i]->len = len; + if (bpf_prog_calc_tag(func[i])) + goto out_free; + func[i]->is_func = 1; + /* Use bpf_prog_F_tag to indicate functions in stack traces. + * Long term would need debug info to populate names + */ + func[i]->aux->name[0] = 'F'; + func[i]->aux->stack_depth = env->subprog_stack_depth[i]; + func[i]->jit_requested = 1; + func[i] = bpf_int_jit_compile(func[i]); + if (!func[i]->jited) { + err = -ENOTSUPP; + goto out_free; + } + cond_resched(); + } + /* at this point all bpf functions were successfully JITed + * now populate all bpf_calls with correct addresses and + * run last pass of JIT + */ + for (i = 0; i <= env->subprog_cnt; i++) { + insn = func[i]->insnsi; + for (j = 0; j < func[i]->len; j++, insn++) { + if (insn->code != (BPF_JMP | BPF_CALL) || + insn->src_reg != BPF_PSEUDO_CALL) + continue; + subprog = insn->off; + insn->off = 0; + insn->imm = (u64 (*)(u64, u64, u64, u64, u64)) + func[subprog]->bpf_func - + __bpf_call_base; + } + } + for (i = 0; i <= env->subprog_cnt; i++) { + old_bpf_func = func[i]->bpf_func; + tmp = bpf_int_jit_compile(func[i]); + if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) { + verbose(env, "JIT doesn't support bpf-to-bpf calls\n"); + err = -EFAULT; + goto out_free; + } + cond_resched(); + } + + /* finally lock prog and jit images for all functions and + * populate kallsysm + */ + for (i = 0; i <= env->subprog_cnt; i++) { + bpf_prog_lock_ro(func[i]); + bpf_prog_kallsyms_add(func[i]); + } + + /* Last step: make now unused interpreter insns from main + * prog consistent for later dump requests, so they can + * later look the same as if they were interpreted only. + */ + for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { + unsigned long addr; + + if (insn->code != (BPF_JMP | BPF_CALL) || + insn->src_reg != BPF_PSEUDO_CALL) + continue; + insn->off = env->insn_aux_data[i].call_imm; + subprog = find_subprog(env, i + insn->off + 1); + addr = (unsigned long)func[subprog + 1]->bpf_func; + addr &= PAGE_MASK; + insn->imm = (u64 (*)(u64, u64, u64, u64, u64)) + addr - __bpf_call_base; + } + + prog->jited = 1; + prog->bpf_func = func[0]->bpf_func; + prog->aux->func = func; + prog->aux->func_cnt = env->subprog_cnt + 1; + return 0; +out_free: + for (i = 0; i <= env->subprog_cnt; i++) + if (func[i]) + bpf_jit_free(func[i]); + kfree(func); + /* cleanup main prog to be interpreted */ + prog->jit_requested = 0; + for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { + if (insn->code != (BPF_JMP | BPF_CALL) || + insn->src_reg != BPF_PSEUDO_CALL) + continue; + insn->off = 0; + insn->imm = env->insn_aux_data[i].call_imm; + } + return err; +} + +static int fixup_call_args(struct bpf_verifier_env *env) +{ +#ifndef CONFIG_BPF_JIT_ALWAYS_ON + struct bpf_prog *prog = env->prog; + struct bpf_insn *insn = prog->insnsi; + int i, depth; +#endif + int err; + + err = 0; + if (env->prog->jit_requested) { + err = jit_subprogs(env); + if (err == 0) + return 0; + } +#ifndef CONFIG_BPF_JIT_ALWAYS_ON + for (i = 0; i < prog->len; i++, insn++) { + if (insn->code != (BPF_JMP | BPF_CALL) || + insn->src_reg != BPF_PSEUDO_CALL) + continue; + depth = get_callee_stack_depth(env, insn, i); + if (depth < 0) + return depth; + bpf_patch_call_args(insn, depth); + } + err = 0; +#endif + return err; +} + /* fixup insn->imm field of bpf_call instructions * and inline eligible helpers as explicit sequence of BPF instructions * @@ -4469,15 +5400,37 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) int i, cnt, delta = 0; for (i = 0; i < insn_cnt; i++, insn++) { - if (insn->code == (BPF_ALU | BPF_MOD | BPF_X) || + if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) || + insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) || + insn->code == (BPF_ALU | BPF_MOD | BPF_X) || insn->code == (BPF_ALU | BPF_DIV | BPF_X)) { - /* due to JIT bugs clear upper 32-bits of src register - * before div/mod operation - */ - insn_buf[0] = BPF_MOV32_REG(insn->src_reg, insn->src_reg); - insn_buf[1] = *insn; - cnt = 2; - new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); + bool is64 = BPF_CLASS(insn->code) == BPF_ALU64; + struct bpf_insn mask_and_div[] = { + BPF_MOV32_REG(insn->src_reg, insn->src_reg), + /* Rx div 0 -> 0 */ + BPF_JMP_IMM(BPF_JNE, insn->src_reg, 0, 2), + BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg), + BPF_JMP_IMM(BPF_JA, 0, 0, 1), + *insn, + }; + struct bpf_insn mask_and_mod[] = { + BPF_MOV32_REG(insn->src_reg, insn->src_reg), + /* Rx mod 0 -> Rx */ + BPF_JMP_IMM(BPF_JEQ, insn->src_reg, 0, 1), + *insn, + }; + struct bpf_insn *patchlet; + + if (insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) || + insn->code == (BPF_ALU | BPF_DIV | BPF_X)) { + patchlet = mask_and_div + (is64 ? 1 : 0); + cnt = ARRAY_SIZE(mask_and_div) - (is64 ? 1 : 0); + } else { + patchlet = mask_and_mod + (is64 ? 1 : 0); + cnt = ARRAY_SIZE(mask_and_mod) - (is64 ? 1 : 0); + } + + new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt); if (!new_prog) return -ENOMEM; @@ -4489,11 +5442,15 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) if (insn->code != (BPF_JMP | BPF_CALL)) continue; + if (insn->src_reg == BPF_PSEUDO_CALL) + continue; if (insn->imm == BPF_FUNC_get_route_realm) prog->dst_needed = 1; if (insn->imm == BPF_FUNC_get_prandom_u32) bpf_user_rnd_init_once(); + if (insn->imm == BPF_FUNC_override_return) + prog->kprobe_override = 1; if (insn->imm == BPF_FUNC_tail_call) { /* If we tail call into other programs, we * cannot make any assumptions since they can @@ -4545,7 +5502,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup * handlers are currently limited to 64 bit only. */ - if (ebpf_jit_enabled() && BITS_PER_LONG == 64 && + if (prog->jit_requested && BITS_PER_LONG == 64 && insn->imm == BPF_FUNC_map_lookup_elem) { map_ptr = env->insn_aux_data[i + delta].map_ptr; if (map_ptr == BPF_MAP_PTR_POISON || @@ -4680,7 +5637,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) env->strict_alignment = true; - if (env->prog->aux->offload) { + if (bpf_prog_is_dev_bound(env->prog->aux)) { ret = bpf_prog_offload_verifier_prep(env); if (ret) goto err_unlock; @@ -4697,12 +5654,12 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) if (!env->explored_states) goto skip_full_check; + env->allow_ptr_leaks = capable(CAP_SYS_ADMIN); + ret = check_cfg(env); if (ret < 0) goto skip_full_check; - env->allow_ptr_leaks = capable(CAP_SYS_ADMIN); - ret = do_check(env); if (env->cur_state) { free_verifier_state(env->cur_state, true); @@ -4717,12 +5674,18 @@ skip_full_check: sanitize_dead_code(env); if (ret == 0) + ret = check_max_stack_depth(env); + + if (ret == 0) /* program is valid, convert *(u32*)(ctx + off) accesses */ ret = convert_ctx_accesses(env); if (ret == 0) ret = fixup_bpf_calls(env); + if (ret == 0) + ret = fixup_call_args(env); + if (log->level && bpf_verifier_log_full(log)) ret = -ENOSPC; if (log->level && !log->ubuf) { |