Commit 6c0ef6ea authored by Byeonguk Jeong's avatar Byeonguk Jeong Committed by Xiaomeng Zhang
Browse files

bpf: Fix out-of-bounds write in trie_get_next_key() 

stable inclusion
from stable-v4.19.323
commit e8494ac079814a53fbc2258d2743e720907488ed
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IB379Y
CVE: CVE-2024-50262

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e8494ac07981



--------------------------------

[ Upstream commit 13400ac8fb80c57c2bfb12ebd35ee121ce9b4d21 ]

trie_get_next_key() allocates a node stack with size trie->max_prefixlen,
while it writes (trie->max_prefixlen + 1) nodes to the stack when it has
full paths from the root to leaves. For example, consider a trie with
max_prefixlen is 8, and the nodes with key 0x00/0, 0x00/1, 0x00/2, ...
0x00/8 inserted. Subsequent calls to trie_get_next_key with _key with
.prefixlen = 8 make 9 nodes be written on the node stack with size 8.

Fixes: b471f2f1 ("bpf: implement MAP_GET_NEXT_KEY command for LPM_TRIE map")
Signed-off-by: default avatarByeonguk Jeong <jungbu2855@gmail.com>
Reviewed-by: default avatarToke Høiland-Jørgensen <toke@kernel.org>
Tested-by: default avatarHou Tao <houtao1@huawei.com>
Acked-by: default avatarHou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/Zxx384ZfdlFYnz6J@localhost.localdomain


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarXiaomeng Zhang <zhangxiaomeng13@huawei.com>
parent 66eb0830

kernel/bpf/lpm_trie.c

+1 −1
Original line number Diff line number Diff line
@@ -665,7 +665,7 @@ static int trie_get_next_key(struct bpf_map *map, void *_key, void *_next_key) 
	if (!key || key->prefixlen > trie->max_prefixlen)

		goto find_leftmost;



	node_stack = kmalloc_array(trie->max_prefixlen,

	node_stack = kmalloc_array(trie->max_prefixlen + 1,

				   sizeof(struct lpm_trie_node *),

				   GFP_ATOMIC | __GFP_NOWARN);

	if (!node_stack)