[PATCH 4.4 009/342] sctp: allow setting SCTP_SACK_IMMEDIATELY by the application

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

------------------

From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

[ Upstream commit 27f7ed2b11d42ab6d796e96533c2076ec220affc ]

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@gmail.com>
Acked-by: Vlad Yasevich <redacted>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sctp/socket.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c

@@ -6640,6 +6640,7 @@ static int sctp_msghdr_parse(const struc
 
 			if (cmsgs->srinfo->sinfo_flags &
 			    ~(SCTP_UNORDERED | SCTP_ADDR_OVER |
+			      SCTP_SACK_IMMEDIATELY |
 			      SCTP_ABORT | SCTP_EOF))
 				return -EINVAL;
 			break;

@@ -6663,6 +6664,7 @@ static int sctp_msghdr_parse(const struc
 
 			if (cmsgs->sinfo->snd_flags &
 			    ~(SCTP_UNORDERED | SCTP_ADDR_OVER |
+			      SCTP_SACK_IMMEDIATELY |
 			      SCTP_ABORT | SCTP_EOF))
 				return -EINVAL;
 			break;