diff options
| author | Alexei Starovoitov <ast@fb.com> | 2016-09-01 18:37:23 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-09-02 10:46:44 -0700 |
| commit | fdc15d388d600d5a1599e14c700af105a5b60761 (patch) | |
| tree | 6c197edb2fc2040e8069ff372baebcda5770ba25 /kernel/bpf | |
| parent | 0515e5999a466dfe6e1924f460da599bb6821487 (diff) | |
bpf: perf_event progs should only use preallocated maps
Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use
preallocated hash maps, since doing memory allocation
in overflow_handler can crash depending on where nmi got triggered.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/verifier.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c1c9e441f0f5..48c2705db22c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2511,6 +2511,20 @@ process_bpf_exit: return 0; } +static int check_map_prog_compatibility(struct bpf_map *map, + struct bpf_prog *prog) + +{ + if (prog->type == BPF_PROG_TYPE_PERF_EVENT && + (map->map_type == BPF_MAP_TYPE_HASH || + map->map_type == BPF_MAP_TYPE_PERCPU_HASH) && + (map->map_flags & BPF_F_NO_PREALLOC)) { + verbose("perf_event programs can only use preallocated hash map\n"); + return -EINVAL; + } + return 0; +} + /* look for pseudo eBPF instructions that access map FDs and * replace them with actual map pointers */ @@ -2518,7 +2532,7 @@ static int replace_map_fd_with_map_ptr(struct verifier_env *env) { struct bpf_insn *insn = env->prog->insnsi; int insn_cnt = env->prog->len; - int i, j; + int i, j, err; for (i = 0; i < insn_cnt; i++, insn++) { if (BPF_CLASS(insn->code) == BPF_LDX && @@ -2562,6 +2576,12 @@ static int replace_map_fd_with_map_ptr(struct verifier_env *env) return PTR_ERR(map); } + err = check_map_prog_compatibility(map, env->prog); + if (err) { + fdput(f); + return err; + } + /* store map pointer inside BPF_LD_IMM64 instruction */ insn[0].imm = (u32) (unsigned long) map; insn[1].imm = ((u64) (unsigned long) map) >> 32; |