Use the .map_allock_check callback to perform allocation checks before
allocating memory for the devmap.
Signed-off-by: Florian Lehner <dev@xxxxxxxxxxx>
---
kernel/bpf/devmap.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 7f3b34452243..9ec346dbf078 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -107,7 +107,7 @@ static inline struct hlist_head *dev_map_index_hash(struct bpf_dtab *dtab,
return &dtab->dev_index_head[idx & (dtab->n_buckets - 1)];
}
-static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
+static int dev_map_alloc_check(union bpf_attr *attr)
{
u32 valsize = attr->value_size;
@@ -121,21 +121,29 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
attr->map_flags & ~DEV_CREATE_FLAG_MASK)
return -EINVAL;
+ if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+ /* hash table size must be power of 2; roundup_pow_of_two() can
+ * overflow into UB on 32-bit arches, so check that
+ */
+ if (attr->max_entries > 1UL << 31)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
+{
/* Lookup returns a pointer straight to dev->ifindex, so make sure the
* verifier prevents writes from the BPF side
*/
attr->map_flags |= BPF_F_RDONLY_PROG;
-
bpf_map_init_from_attr(&dtab->map, attr);
if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
- /* hash table size must be power of 2; roundup_pow_of_two() can
- * overflow into UB on 32-bit arches, so check that first
+ /* hash table size must be power of 2
*/
- if (dtab->map.max_entries > 1UL << 31)
- return -EINVAL;
-
dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets,
@@ -1040,6 +1048,7 @@ static u64 dev_map_mem_usage(const struct bpf_map *map)
BTF_ID_LIST_SINGLE(dev_map_btf_ids, struct, bpf_dtab)
const struct bpf_map_ops dev_map_ops = {
.map_meta_equal = bpf_map_meta_equal,
+ .map_alloc_check = dev_map_alloc_check,
.map_alloc = dev_map_alloc,
.map_free = dev_map_free,
.map_get_next_key = dev_map_get_next_key,
@@ -1054,6 +1063,7 @@ const struct bpf_map_ops dev_map_ops = {
const struct bpf_map_ops dev_map_hash_ops = {
.map_meta_equal = bpf_map_meta_equal,
+ .map_alloc_check = dev_map_alloc_check,
.map_alloc = dev_map_alloc,
.map_free = dev_map_free,
.map_get_next_key = dev_map_hash_get_next_key,
--
2.45.2
