4.14-stable review patch. If anyone has any objections, please let me know.
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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;