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

sctp: make sure stream nums can match optlen in sctp_setsockopt_reset_streams

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: sctp-make-sure-stream-nums-can-match-optlen-in-sctp_setsockopt_reset_streams.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@vger.kernel.org know about it.

From foo@baz Sun Dec 31 11:12:48 CET 2017

From: Xin Long lucien.xin@gmail.com Date: Sun, 10 Dec 2017 15:40:51 +0800 Subject: sctp: make sure stream nums can match optlen in sctp_setsockopt_reset_streams

From: Xin Long lucien.xin@gmail.com

[ Upstream commit 2342b8d95bcae5946e1b9b8d58645f37500ef2e7 ]

Now in sctp_setsockopt_reset_streams, it only does the check optlen < sizeof(*params) for optlen. But it's not enough, as params->srs_number_streams should also match optlen.

If the streams in params->srs_stream_list are less than stream nums in params->srs_number_streams, later when dereferencing the stream list, it could cause a slab-out-of-bounds crash, as reported by syzbot.

This patch is to fix it by also checking the stream numbers in sctp_setsockopt_reset_streams to make sure at least it's not greater than the streams in the list.

Fixes: 7f9d68ac944e ("sctp: implement sender-side procedures for SSN Reset Request Parameter") Reported-by: Dmitry Vyukov dvyukov@google.com Signed-off-by: Xin Long lucien.xin@gmail.com Acked-by: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Acked-by: Neil Horman nhorman@tuxdriver.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sctp/socket.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -3874,13 +3874,17 @@ static int sctp_setsockopt_reset_streams struct sctp_association *asoc; int retval = -EINVAL;

- if (optlen < sizeof(struct sctp_reset_streams)) + if (optlen < sizeof(*params)) return -EINVAL;

params = memdup_user(optval, optlen); if (IS_ERR(params)) return PTR_ERR(params);

+ if (params->srs_number_streams * sizeof(__u16) > + optlen - sizeof(*params)) + goto out; + asoc = sctp_id2assoc(sk, params->srs_assoc_id); if (!asoc) goto out;

Patches currently in stable-queue which might be from lucien.xin@gmail.com are

queue-4.14/sctp-make-sure-stream-nums-can-match-optlen-in-sctp_setsockopt_reset_streams.patch queue-4.14/ipv6-mcast-better-catch-silly-mtu-values.patch