The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 962e5a40358787105f126ab1dc01604da3d169e9 Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso pablo@netfilter.org Date: Tue, 30 Nov 2021 11:34:04 +0100 Subject: [PATCH] netfilter: nft_exthdr: break evaluation if setting TCP option fails
Break rule evaluation on malformed TCP options.
Fixes: 99d1712bc41c ("netfilter: exthdr: tcp option set support") Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c index af4ee874a067..dbe1f2e7dd9e 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,