Commit 068d8bd3 authored Dec 29, 2015 by Xin Long Committed by David S. Miller Dec 30, 2015

sctp: sctp should release assoc when sctp_make_abort_user return NULL in sctp_close



In sctp_close, sctp_make_abort_user may return NULL because of memory
allocation failure. If this happens, it will bypass any state change
and never free the assoc. The assoc has no chance to be freed and it
will be kept in memory with the state it had even after the socket is
closed by sctp_close().

So if sctp_make_abort_user fails to allocate memory, we should abort
the asoc via sctp_primitive_ABORT as well. Just like the annotation in
sctp_sf_cookie_wait_prm_abort and sctp_sf_do_9_1_prm_abort said,
"Even if we can't send the ABORT due to low memory delete the TCB.
This is a departure from our typical NOMEM handling".

But then the chunk is NULL (low memory) and the SCTP_CMD_REPLY cmd would
dereference the chunk pointer, and system crash. So we should add
SCTP_CMD_REPLY cmd only when the chunk is not NULL, just like other
places where it adds SCTP_CMD_REPLY cmd.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent a0ccc3f2

net/sctp/sm_statefuns.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -4829,6 +4829,7 @@ sctp_disposition_t sctp_sf_do_9_1_prm_abort(

		retval = SCTP_DISPOSITION_CONSUME;

		if (abort)
		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));

		/* Even if we can't send the ABORT due to low memory delete the
		@@ -4966,6 +4967,7 @@ sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
		SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
		retval = SCTP_DISPOSITION_CONSUME;

		if (abort)
		sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));

		sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,

net/sctp/socket.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -1516,7 +1516,6 @@ static void sctp_close(struct sock *sk, long timeout)
		struct sctp_chunk *chunk;

		chunk = sctp_make_abort_user(asoc, NULL, 0);
		if (chunk)
		sctp_primitive_ABORT(net, asoc, chunk);
		} else
		sctp_primitive_SHUTDOWN(net, asoc, NULL);

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