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Diffstat (limited to 'kernel/bpf/arraymap.c')
-rw-r--r--kernel/bpf/arraymap.c104
1 files changed, 75 insertions, 29 deletions
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 7c25426d3cf5..b1f66480135b 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -49,34 +49,64 @@ 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);
- struct bpf_array *array;
- u64 array_size;
- u32 elem_size;
/* 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);
+ max_entries = attr->max_entries;
+
+ /* On 32 bit archs roundup_pow_of_two() with max_entries that has
+ * upper most bit set in u32 space is undefined behavior due to
+ * resulting 1U << 32, so do it manually here in u64 space.
+ */
+ mask64 = fls_long(max_entries - 1);
+ mask64 = 1ULL << mask64;
+ mask64 -= 1;
+
+ index_mask = mask64;
+ if (unpriv) {
+ /* round up array size to nearest power of 2,
+ * since cpu will speculate within index_mask limits
+ */
+ max_entries = index_mask + 1;
+ /* Check for overflows. */
+ if (max_entries < attr->max_entries)
+ return ERR_PTR(-E2BIG);
+ }
+
array_size = sizeof(*array);
if (percpu)
- array_size += (u64) attr->max_entries * sizeof(void *);
+ array_size += (u64) max_entries * sizeof(void *);
else
- array_size += (u64) attr->max_entries * elem_size;
+ array_size += (u64) max_entries * elem_size;
/* make sure there is no u32 overflow later in round_up() */
if (array_size >= U32_MAX - PAGE_SIZE)
@@ -86,14 +116,11 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr)
array = bpf_map_area_alloc(array_size, numa_node);
if (!array)
return ERR_PTR(-ENOMEM);
+ array->index_mask = index_mask;
+ 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)
@@ -121,12 +148,13 @@ static void *array_map_lookup_elem(struct bpf_map *map, void *key)
if (unlikely(index >= array->map.max_entries))
return NULL;
- return array->value + array->elem_size * index;
+ return array->value + array->elem_size * (index & array->index_mask);
}
/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
static u32 array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
struct bpf_insn *insn = insn_buf;
u32 elem_size = round_up(map->value_size, 8);
const int ret = BPF_REG_0;
@@ -135,7 +163,12 @@ static u32 array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
- *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
+ if (map->unpriv_array) {
+ *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
+ *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
+ } else {
+ *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
+ }
if (is_power_of_2(elem_size)) {
*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
@@ -157,7 +190,7 @@ static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
if (unlikely(index >= array->map.max_entries))
return NULL;
- return this_cpu_ptr(array->pptrs[index]);
+ return this_cpu_ptr(array->pptrs[index & array->index_mask]);
}
int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
@@ -177,7 +210,7 @@ int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
*/
size = round_up(map->value_size, 8);
rcu_read_lock();
- pptr = array->pptrs[index];
+ pptr = array->pptrs[index & array->index_mask];
for_each_possible_cpu(cpu) {
bpf_long_memcpy(value + off, per_cpu_ptr(pptr, cpu), size);
off += size;
@@ -225,10 +258,11 @@ static int array_map_update_elem(struct bpf_map *map, void *key, void *value,
return -EEXIST;
if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
- memcpy(this_cpu_ptr(array->pptrs[index]),
+ memcpy(this_cpu_ptr(array->pptrs[index & array->index_mask]),
value, map->value_size);
else
- memcpy(array->value + array->elem_size * index,
+ memcpy(array->value +
+ array->elem_size * (index & array->index_mask),
value, map->value_size);
return 0;
}
@@ -262,7 +296,7 @@ int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
*/
size = round_up(map->value_size, 8);
rcu_read_lock();
- pptr = array->pptrs[index];
+ pptr = array->pptrs[index & array->index_mask];
for_each_possible_cpu(cpu) {
bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value + off, size);
off += size;
@@ -296,6 +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,
@@ -306,6 +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,
@@ -314,12 +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)
@@ -443,7 +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,
@@ -530,7 +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,
@@ -561,7 +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,
@@ -579,7 +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;
@@ -613,6 +652,7 @@ static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
static u32 array_of_map_gen_lookup(struct bpf_map *map,
struct bpf_insn *insn_buf)
{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 elem_size = round_up(map->value_size, 8);
struct bpf_insn *insn = insn_buf;
const int ret = BPF_REG_0;
@@ -621,7 +661,12 @@ static u32 array_of_map_gen_lookup(struct bpf_map *map,
*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
- *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
+ if (map->unpriv_array) {
+ *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
+ *insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
+ } else {
+ *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
+ }
if (is_power_of_2(elem_size))
*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
else
@@ -636,6 +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,
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-21 01:08:54 +0000