From: Byeonguk Jeong jungbu2855@gmail.com

stable inclusion from stable-v4.19.323 commit e8494ac079814a53fbc2258d2743e720907488ed category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IB4U3C CVE: CVE-2024-50262

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

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[ 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: b471f2f1de8b ("bpf: implement MAP_GET_NEXT_KEY command for LPM_TRIE map") Signed-off-by: Byeonguk Jeong jungbu2855@gmail.com Reviewed-by: Toke Høiland-Jørgensen toke@kernel.org Tested-by: Hou Tao houtao1@huawei.com Acked-by: Hou Tao houtao1@huawei.com Link: https://lore.kernel.org/r/Zxx384ZfdlFYnz6J@localhost.localdomain Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Xiaomeng Zhang zhangxiaomeng13@huawei.com --- kernel/bpf/lpm_trie.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c index 796d1c4e5037..ac2da83c11b9 100644 --- a/kernel/bpf/lpm_trie.c +++ b/kernel/bpf/lpm_trie.c @@ -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)