From 201c59bb7ba69fd6a41ac6606d8049b94fb26232 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Sun, 10 Dec 2017 15:40:51 +0800 Subject: [PATCH] sctp: make sure stream nums can match optlen in sctp_setsockopt_reset_streams [ 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 Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Acked-by: Neil Horman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sctp/socket.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 1977238dc023..df806b8819aa 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -3874,13 +3874,17 @@ static int sctp_setsockopt_reset_streams(struct sock *sk, 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; -- 2.20.1