sctp: Fix SHUTDOWN CTSN Ack in the peer restart case

commit 12dfd78e3a74825e6f0bc8df7ef9f938fbc6bfe3 upstream.

When starting shutdown in sctp_sf_do_dupcook_a(), get the value for
SHUTDOWN Cumulative TSN Ack from the new association, which is
reconstructed from the cookie, instead of the old association, which
the peer doesn't have anymore.

Otherwise the SHUTDOWN is either ignored or replied to with an ABORT
by the peer because CTSN Ack doesn't match the peer's Initial TSN.

Fixes: bdf6fa52f01b ("sctp: handle association restarts when the socket is closed.")
Signed-off-by: Jere Leppänen <jere.leppanen@nokia.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index fb546b2d67ca85fddc357229b2771f5b487924f5..ce6053be60bc8975ded5bf7449a6138d7780233d 100644 (file)
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -871,7 +871,11 @@ struct sctp_chunk *sctp_make_shutdown(const struct sctp_association *asoc,
        struct sctp_chunk *retval;
        __u32 ctsn;
 
-       ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
+       if (chunk && chunk->asoc)
+               ctsn = sctp_tsnmap_get_ctsn(&chunk->asoc->peer.tsn_map);
+       else
+               ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
+
        shut.cum_tsn_ack = htonl(ctsn);
 
        retval = sctp_make_control(asoc, SCTP_CID_SHUTDOWN, 0,