This is a note to let you know that I've just added the patch titled
Revert "netfilter: conntrack: fix bug in for_each_sctp_chunk"
to the 4.14-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:
revert-netfilter-conntrack-fix-bug-in-for_each_sctp_.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0e7528b091ccdcf79892af732c349830c6d78d7d
Author: Florian Westphal <fw@xxxxxxxxx>
Date: Thu Jan 26 02:35:21 2023 +0100
Revert "netfilter: conntrack: fix bug in for_each_sctp_chunk"
[ Upstream commit bd0e06f0def75ba26572a94e5350324474a55562 ]
There is no bug. If sch->length == 0, this would result in an infinite
loop, but first caller, do_basic_checks(), errors out in this case.
After this change, packets with bogus zero-length chunks are no longer
detected as invalid, so revert & add comment wrt. 0 length check.
Fixes: 98ee00774525 ("netfilter: conntrack: fix bug in for_each_sctp_chunk")
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
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 cffd37f56c5c0..6166c2012e0d8 100644
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -182,10 +182,11 @@ static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
}
#endif
+/* do_basic_checks ensures sch->length > 0, do not use before */
#define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) \
for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0; \
- ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))) && \
- (sch)->length; \
+ (offset) < (skb)->len && \
+ ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))); \
(offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
/* Some validity checks to make sure the chunks are fine */
