This is a note to let you know that I've just added the patch titled
sctp: add vtag check in sctp_sf_violation
to the 4.9-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:
sctp-add-vtag-check-in-sctp_sf_violation.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7e969dfce9b8b6d7ce50dcfb41ea42babe2a70ca
Author: Xin Long <lucien.xin@xxxxxxxxx>
Date: Wed Oct 20 07:42:45 2021 -0400
sctp: add vtag check in sctp_sf_violation
[ Upstream commit aa0f697e45286a6b5f0ceca9418acf54b9099d99 ]
sctp_sf_violation() is called when processing HEARTBEAT_ACK chunk
in cookie_wait state, and some other places are also using it.
The vtag in the chunk's sctphdr should be verified, otherwise, as
later in chunk length check, it may send abort with the existent
asoc's vtag, which can be exploited by one to cook a malicious
chunk to terminate a SCTP asoc.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index c3d293dc8281..f71991520ad6 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -4333,6 +4333,9 @@ sctp_disposition_t sctp_sf_violation(struct net *net,
{
struct sctp_chunk *chunk = arg;
+ if (!sctp_vtag_verify(chunk, asoc))
+ return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
+
/* Make sure that the chunk has a valid length. */
if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
