diff options
authorVlad Yasevich <>2014-10-03 18:16:20 -0400
committerGreg Kroah-Hartman <>2014-10-15 12:29:23 +0200
commit404db05025f2fb873b0569a99cf541519fec607f (patch)
parented54569e2b2be022e8e155e23fdca672690b6642 (diff)
sctp: handle association restarts when the socket is closed.
[ Upstream commit bdf6fa52f01b941d4a80372d56de465bdbbd1d23 ] Currently association restarts do not take into consideration the state of the socket. When a restart happens, the current assocation simply transitions into established state. This creates a condition where a remote system, through a the restart procedure, may create a local association that is no way reachable by user. The conditions to trigger this are as follows: 1) Remote does not acknoledge some data causing data to remain outstanding. 2) Local application calls close() on the socket. Since data is still outstanding, the association is placed in SHUTDOWN_PENDING state. However, the socket is closed. 3) The remote tries to create a new association, triggering a restart on the local system. The association moves from SHUTDOWN_PENDING to ESTABLISHED. At this point, it is no longer reachable by any socket on the local system. This patch addresses the above situation by moving the newly ESTABLISHED association into SHUTDOWN-SENT state and bundling a SHUTDOWN after the COOKIE-ACK chunk. This way, the restarted associate immidiately enters the shutdown procedure and forces the termination of the unreachable association. Reported-by: David Laight <> Signed-off-by: Vlad Yasevich <> Signed-off-by: David S. Miller <> Signed-off-by: Greg Kroah-Hartman <>
2 files changed, 17 insertions, 4 deletions
diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
index f22538e68245..d4a20d00461c 100644
--- a/include/net/sctp/command.h
+++ b/include/net/sctp/command.h
@@ -115,7 +115,7 @@ typedef enum {
* analysis of the state functions, but in reality just taken from
* thin air in the hopes othat we don't trigger a kernel panic.
typedef union {
void *zero_all; /* Set to NULL to clear the entire union */
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index d3f1ea460c50..c8f606324134 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1775,9 +1775,22 @@ static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
/* Update the content of current association. */
sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
- sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
- sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+ if (sctp_state(asoc, SHUTDOWN_PENDING) &&
+ (sctp_sstate(asoc->, CLOSING) ||
+ sock_flag(asoc->, SOCK_DEAD))) {
+ /* if were currently in SHUTDOWN_PENDING, but the socket
+ * has been closed by user, don't transition to ESTABLISHED.
+ * Instead trigger SHUTDOWN bundled with COOKIE_ACK.
+ */
+ sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+ return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
+ commands);
+ } else {
+ sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
+ sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
+ }