Patch "netfilter: nft_exthdr: break evaluation if setting TCP option fails" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    netfilter: nft_exthdr: break evaluation if setting TCP option fails

to the 5.10-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_exthdr-break-evaluation-if-setting-tcp.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit e9f67d7e8acd114583f0990dc1e2921888391d51
Author: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Date:   Tue Nov 30 11:34:04 2021 +0100

    netfilter: nft_exthdr: break evaluation if setting TCP option fails
    
    [ Upstream commit 962e5a40358787105f126ab1dc01604da3d169e9 ]
    
    Break rule evaluation on malformed TCP options.
    
    Fixes: 99d1712bc41c ("netfilter: exthdr: tcp option set support")
    Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
    Stable-dep-of: 28427f368f0e ("netfilter: nft_exthdr: Fix non-linear header modification")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 73f82483f2429..10a510fef75c5 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -236,7 +236,7 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
 
 	tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
 	if (!tcph)
-		return;
+		goto err;
 
 	opt = (u8 *)tcph;
 	for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
@@ -251,16 +251,16 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
 			continue;
 
 		if (i + optl > tcphdr_len || priv->len + priv->offset > optl)
-			return;
+			goto err;
 
 		if (skb_ensure_writable(pkt->skb,
 					nft_thoff(pkt) + i + priv->len))
-			return;
+			goto err;
 
 		tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff,
 					      &tcphdr_len);
 		if (!tcph)
-			return;
+			goto err;
 
 		offset = i + priv->offset;
 
@@ -303,6 +303,9 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
 
 		return;
 	}
+	return;
+err:
+	regs->verdict.code = NFT_BREAK;
 }
 
 static void nft_exthdr_sctp_eval(const struct nft_expr *expr,