diff options
| author | Dan Carpenter <dan.carpenter@oracle.com> | 2017-09-13 23:00:54 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-12 09:51:20 (GMT) |
| commit | b70bb9bb7277aa396eafab6a313ee829c7957587 (patch) | |
| tree | 7a96dad6999ebe397f6958d98d2cd01f61267be2 /include | |
| parent | f86d3b1a28a7271774fe4e8a9a028f6b209e1fd3 (diff) | |
| download | linux-b70bb9bb7277aa396eafab6a313ee829c7957587.tar.xz | |
sctp: potential read out of bounds in sctp_ulpevent_type_enabled()
[ Upstream commit fa5f7b51fc3080c2b195fa87c7eca7c05e56f673 ]
This code causes a static checker warning because Smatch doesn't trust
anything that comes from skb->data. I've reviewed this code and I do
think skb->data can be controlled by the user here.
The sctp_event_subscribe struct has 13 __u8 fields and we want to see
if ours is non-zero. sn_type can be any value in the 0-USHRT_MAX range.
We're subtracting SCTP_SN_TYPE_BASE which is 1 << 15 so we could read
either before the start of the struct or after the end.
This is a very old bug and it's surprising that it would go undetected
for so long but my theory is that it just doesn't have a big impact so
it would be hard to notice.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/sctp/ulpevent.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/include/net/sctp/ulpevent.h b/include/net/sctp/ulpevent.h index 2c098cd..231df4f 100644 --- a/include/net/sctp/ulpevent.h +++ b/include/net/sctp/ulpevent.h @@ -141,8 +141,12 @@ __u16 sctp_ulpevent_get_notification_type(const struct sctp_ulpevent *event); static inline int sctp_ulpevent_type_enabled(__u16 sn_type, struct sctp_event_subscribe *mask) { + int offset = sn_type - SCTP_SN_TYPE_BASE; char *amask = (char *) mask; - return amask[sn_type - SCTP_SN_TYPE_BASE]; + + if (offset >= sizeof(struct sctp_event_subscribe)) + return 0; + return amask[offset]; } /* Given an event subscription, is this event enabled? */ |