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bpf: Fix map leak in HASH_OF_MAPS map

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[ Upstream commit 1d4e1eab456e1ee92a94987499b211db05f900ea ]

Fix HASH_OF_MAPS bug of not putting inner map pointer on bpf_map_elem_update()
operation. This is due to per-cpu extra_elems optimization, which bypassed
free_htab_elem() logic doing proper clean ups. Make sure that inner map is put
properly in optimized case as well.

Fixes: 8c290e60fa ("bpf: fix hashmap extra_elems logic")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200729040913.2815687-1-andriin@fb.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Andrii Nakryiko 2020-07-28 21:09:12 -07:00 committed by Greg Kroah-Hartman
parent 43c390b751
commit fe58e3dd6e
1 changed files with 9 additions and 3 deletions
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12
kernel/bpf/hashtab.c
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@ -675,15 +675,20 @@ static void htab_elem_free_rcu(struct rcu_head *head)
preempt_enable();
}
static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l)
{
struct bpf_map *map = &htab->map;
void *ptr;
if (map->ops->map_fd_put_ptr) {
void *ptr = fd_htab_map_get_ptr(map, l);
ptr = fd_htab_map_get_ptr(map, l);
map->ops->map_fd_put_ptr(ptr);
}
}
static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
{
htab_put_fd_value(htab, l);
if (htab_is_prealloc(htab)) {
__pcpu_freelist_push(&htab->freelist, &l->fnode);
@ -735,6 +740,7 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
*/
pl_new = this_cpu_ptr(htab->extra_elems);
l_new = *pl_new;
htab_put_fd_value(htab, old_elem);
*pl_new = old_elem;
} else {
struct pcpu_freelist_node *l;