This is a note to let you know that I've just added the patch titled
netfilter: nft_payload: sanitize offset and length before calling skb_checksum()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netfilter-nft_payload-sanitize-offset-and-length-bef.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 48e0e9c89122abe7f304660afdd936b2d77ae65a
Author: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Date: Wed Oct 30 23:13:48 2024 +0100
netfilter: nft_payload: sanitize offset and length before calling skb_checksum()
[ 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: 7ec3f7b47b8d ("netfilter: nft_payload: add packet mangling support")
Reported-by: Slavin Liu <slavin-ayu@xxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index a4f9a150812a3..e40948b508588 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -532,6 +532,9 @@ static void nft_payload_set_eval(const struct nft_expr *expr,
if ((priv->csum_type == NFT_PAYLOAD_CSUM_INET || priv->csum_flags) &&
(priv->base != NFT_PAYLOAD_TRANSPORT_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);
