diff options
| author | Dan Carpenter <dan.carpenter@oracle.com> | 2017-09-14 02:00:54 +0300 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2017-11-06 15:29:25 +0100 |
| commit | 0d59d94365a8beebddb6f26c6181f4272ddaef76 (patch) | |
| tree | a27f48e94571623ff0b8c5624caed2e80ca2b749 /include/net | |
| parent | 782d6f82d97099b1a0b1df2dbba731c5b152da64 (diff) | |
sctp: potential read out of bounds in sctp_ulpevent_type_enabled()
commit fa5f7b51fc3080c2b195fa87c7eca7c05e56f673 upstream.
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>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'include/net')
| -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 ca4693b4e..00c0e5bf5 100644 --- a/include/net/sctp/ulpevent.h +++ b/include/net/sctp/ulpevent.h @@ -143,8 +143,12 @@ __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? */ |