netfilter: nft_payload: sanitize offset and length before calling skb_checksum()

BugLink: https://bugs.launchpad.net/bugs/2099996

[ Upstream commit d5953d680f7e96208c29ce4139a0e38de87a57fe ]

If access to offset + length is larger than the skbuff length, then
skb_checksum() triggers BUG_ON().

skb_checksum() internally subtracts the length parameter while iterating
over skbuff, BUG_ON(len) at the end of it checks that the expected
length to be included in the checksum calculation is fully consumed.

Fixes: 7ec3f7b47b ("netfilter: nft_payload: add packet mangling support")
Reported-by: Slavin Liu <slavin-ayu@qq.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
CVE-2024-50251
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
This commit is contained in:
Pablo Neira Ayuso
2025-02-25 22:59:22 +09:00
committed by Stefan Bader
parent b96f757e5e
commit b0ee558538
+3
View File
@@ -904,6 +904,9 @@ static void nft_payload_set_eval(const struct nft_expr *expr,
((priv->base != NFT_PAYLOAD_TRANSPORT_HEADER &&
priv->base != NFT_PAYLOAD_INNER_HEADER) ||
skb->ip_summed != CHECKSUM_PARTIAL)) {
if (offset + priv->len > skb->len)
goto err;
fsum = skb_checksum(skb, offset, priv->len, 0);
tsum = csum_partial(src, priv->len, 0);