This is a note to let you know that I've just added the patch titled netfilter: conntrack: fix bug in for_each_sctp_chunk to the 6.1-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-conntrack-fix-bug-in-for_each_sctp_chunk.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 099acc3ff752a5871df012b0698db0d6bfc1c4c0 Author: Sriram Yagnaraman <sriram.yagnaraman@xxxxxxxx> Date: Tue Jan 24 02:47:19 2023 +0100 netfilter: conntrack: fix bug in for_each_sctp_chunk [ Upstream commit 98ee0077452527f971567db01386de3c3d97ce13 ] skb_header_pointer() will return NULL if offset + sizeof(_sch) exceeds skb->len, so this offset < skb->len test is redundant. if sch->length == 0, this will end up in an infinite loop, add a check for sch->length > 0 Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.") Suggested-by: Florian Westphal <fw@xxxxxxxxx> Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@xxxxxxxx> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c index 3704d1c7d3c2..ee317f9a22e5 100644 --- a/net/netfilter/nf_conntrack_proto_sctp.c +++ b/net/netfilter/nf_conntrack_proto_sctp.c @@ -155,8 +155,8 @@ static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct) #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) \ for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0; \ - (offset) < (skb)->len && \ - ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))); \ + ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))) && \ + (sch)->length; \ (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++) /* Some validity checks to make sure the chunks are fine */