[PATCH 3.16.y-ckt 122/129] sctp: allow setting SCTP_SACK_IMMEDIATELY by the application

[Luis Henriques]

3.16.7-ckt25 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>

commit 27f7ed2b11d42ab6d796e96533c2076ec220affc upstream.

This patch extends commit b93d6471748d ("sctp: implement the sender side
for SACK-IMMEDIATELY extension") as it didn't white list
SCTP_SACK_IMMEDIATELY on sctp_msghdr_parse(), causing it to be
understood as an invalid flag and returning -EINVAL to the application.

Note that the actual handling of the flag is already there in
sctp_datamsg_from_user().

https://tools.ietf.org/html/rfc7053#section-7

Fixes: b93d6471748d ("sctp: implement the sender side for SACK-IMMEDIATELY extension")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Acked-by: Vlad Yasevich <vyasevich@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[ luis: backported to 3.16:
  - dropped changes to SCTP_SNDINFO case ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 net/sctp/socket.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 88c5befcb569..70bac7a75b9c 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6464,6 +6464,7 @@ static int sctp_msghdr_parse(const struct msghdr *msg, sctp_cmsgs_t *cmsgs)
 			/* Minimally, validate the sinfo_flags. */
 			if (cmsgs->info->sinfo_flags &
 			    ~(SCTP_UNORDERED | SCTP_ADDR_OVER |
+			      SCTP_SACK_IMMEDIATELY |
 			      SCTP_ABORT | SCTP_EOF))
 				return -EINVAL;
 			break;