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bpf: hashtab: move checks out of alloc function 

Use the new callback to perform allocation checks for hash maps.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Jakub Kicinski 2018-01-11 20:29:05 -08:00 committed by Daniel Borkmann
parent daffc5a2e6
commit 9328e0d1bc
1 changed files with 73 additions and 50 deletions
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123
kernel/bpf/hashtab.c
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@ -227,6 +227,70 @@ static int alloc_extra_elems(struct bpf_htab *htab)
}
/* Called from syscall */
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);
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);
int numa_node = bpf_map_attr_numa_node(attr);
BUILD_BUG_ON(offsetof(struct htab_elem, htab) !=
offsetof(struct htab_elem, hash_node.pprev));
BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
offsetof(struct htab_elem, hash_node.pprev));
if (lru && !capable(CAP_SYS_ADMIN))
/* LRU implementation is much complicated than other
* maps. Hence, limit to CAP_SYS_ADMIN for now.
*/
return -EPERM;
if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK)
/* reserved bits should not be used */
return -EINVAL;
if (!lru && percpu_lru)
return -EINVAL;
if (lru && !prealloc)
return -ENOTSUPP;
if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
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 ||
@ -245,52 +309,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
int err, i;
u64 cost;
BUILD_BUG_ON(offsetof(struct htab_elem, htab) !=
offsetof(struct htab_elem, hash_node.pprev));
BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
offsetof(struct htab_elem, hash_node.pprev));
if (lru && !capable(CAP_SYS_ADMIN))
/* LRU implementation is much complicated than other
* maps. Hence, limit to CAP_SYS_ADMIN for now.
*/
return ERR_PTR(-EPERM);
if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK)
/* reserved bits should not be used */
return ERR_PTR(-EINVAL);
if (!lru && percpu_lru)
return ERR_PTR(-EINVAL);
if (lru && !prealloc)
return ERR_PTR(-ENOTSUPP);
if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
return ERR_PTR(-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 ERR_PTR(-EINVAL);
if (attr->key_size > MAX_BPF_STACK)
/* eBPF programs initialize keys on stack, so they cannot be
* larger than max stack size
*/
return ERR_PTR(-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 ERR_PTR(-E2BIG);
htab = kzalloc(sizeof(*htab), GFP_USER);
if (!htab)
return ERR_PTR(-ENOMEM);
@ -1142,6 +1160,7 @@ 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,
@ -1152,6 +1171,7 @@ 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,
@ -1235,6 +1255,7 @@ 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,
@ -1244,6 +1265,7 @@ 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,
@ -1252,11 +1274,11 @@ 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)
@ -1327,7 +1349,7 @@ 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;
@ -1371,6 +1393,7 @@ 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,