[PATCH 3.16.y-ckt 090/126] sctp: use the same clock as if sock source timestamps were on

[Luis Henriques]

3.16.7-ckt22 -stable review patch.  If anyone has any objections, please let me know.

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

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

commit cb5e173ed7c03a0d4630ce68a95a186cce3cc872 upstream.

SCTP echoes a cookie o INIT ACK chunks that contains a timestamp, for
detecting stale cookies. This cookie is echoed back to the server by the
client and then that timestamp is checked.

Thing is, if the listening socket is using packet timestamping, the
cookie is encoded with ktime_get() value and checked against
ktime_get_real(), as done by __net_timestamp().

The fix is to sctp also use ktime_get_real(), so we can compare bananas
with bananas later no matter if packet timestamping was enabled or not.

Fixes: 52db882f3fc2 ("net: sctp: migrate cookie life from timeval to ktime")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner at gmail.com>
Acked-by: Vlad Yasevich <vyasevich at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/sctp/sm_make_chunk.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 371a152d9759..642c11570285 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1652,7 +1652,7 @@ static sctp_cookie_param_t *sctp_pack_cookie(const struct sctp_endpoint *ep,
 
 	/* Set an expiration time for the cookie.  */
 	cookie->c.expiration = ktime_add(asoc->cookie_life,
-					 ktime_get());
+					 ktime_get_real());
 
 	/* Copy the peer's init packet.  */
 	memcpy(&cookie->c.peer_init[0], init_chunk->chunk_hdr,
@@ -1780,7 +1780,7 @@ no_hmac:
 	if (sock_flag(ep->base.sk, SOCK_TIMESTAMP))
 		kt = skb_get_ktime(skb);
 	else
-		kt = ktime_get();
+		kt = ktime_get_real();
 
 	if (!asoc && ktime_before(bear_cookie->expiration, kt)) {
 		/*