Re: [PATCH net] sctp: make sure stream nums can match optlen in sctp_setsockopt_reset_streams
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From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Date: 2017-12-10 13:51:54
Also in:
linux-sctp
On Sun, Dec 10, 2017 at 03:40:51PM +0800, Xin Long wrote:
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>
quoted hunk ↗ jump to hunk
--- 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 014847e..dbf140d 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c@@ -3891,13 +3891,17 @@ 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;-- 2.1.0