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sctp: make sure stream nums can match optlen in sctp_setsockopt_reset_streams 

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: 7f9d68ac94 ("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>
This commit is contained in:
Xin Long 2017-12-10 15:40:51 +08:00 committed by David S. Miller
parent 8f659a03a0
commit 2342b8d95b
1 changed files with 5 additions and 1 deletions
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6
net/sctp/socket.c
View File

@ -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;