Commit 245709ec authored by Xin Long's avatar Xin Long Committed by David S. Miller
Browse files

sctp: move the format error check out of __sctp_sf_do_9_1_abort 



When T2 timer is to be stopped, the asoc should also be deleted,
otherwise, there will be no chance to call sctp_association_free
and the asoc could last in memory forever.

However, in sctp_sf_shutdown_sent_abort(), after adding the cmd
SCTP_CMD_TIMER_STOP for T2 timer, it may return error due to the
format error from __sctp_sf_do_9_1_abort() and miss adding
SCTP_CMD_ASSOC_FAILED where the asoc will be deleted.

This patch is to fix it by moving the format error check out of
__sctp_sf_do_9_1_abort(), and do it before adding the cmd
SCTP_CMD_TIMER_STOP for T2 timer.

Thanks Hangbin for reporting this issue by the fuzz testing.

v1->v2:
  - improve the comment in the code as Marcelo's suggestion.

Fixes: 96ca468b ("sctp: check invalid value of length parameter in error cause")
Reported-by: default avatarHangbin Liu <liuhangbin@gmail.com>
Acked-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8a9093c7

net/sctp/sm_statefuns.c

+20 −9
Original line number Diff line number Diff line
@@ -170,6 +170,16 @@ static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 
	return true;

}



/* Check for format error in an ABORT chunk */

static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk)

{

	struct sctp_errhdr *err;



	sctp_walk_errors(err, chunk->chunk_hdr);



	return (void *)err == (void *)chunk->chunk_end;

}



/**********************************************************

 * These are the state functions for handling chunk events.

 **********************************************************/
@@ -2255,6 +2265,9 @@ enum sctp_disposition sctp_sf_shutdown_pending_abort( 
		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))

		return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);



	if (!sctp_err_chunk_valid(chunk))

		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);



	return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);

}
@@ -2298,6 +2311,9 @@ enum sctp_disposition sctp_sf_shutdown_sent_abort( 
		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))

		return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);



	if (!sctp_err_chunk_valid(chunk))

		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);



	/* Stop the T2-shutdown timer. */

	sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,

			SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
@@ -2565,6 +2581,9 @@ enum sctp_disposition sctp_sf_do_9_1_abort( 
		    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))

		return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);



	if (!sctp_err_chunk_valid(chunk))

		return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);



	return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);

}
@@ -2582,16 +2601,8 @@ static enum sctp_disposition __sctp_sf_do_9_1_abort( 


	/* See if we have an error cause code in the chunk.  */

	len = ntohs(chunk->chunk_hdr->length);

	if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {

		struct sctp_errhdr *err;



		sctp_walk_errors(err, chunk->chunk_hdr);

		if ((void *)err != (void *)chunk->chunk_end)

			return sctp_sf_pdiscard(net, ep, asoc, type, arg,

						commands);



	if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))

		error = ((struct sctp_errhdr *)chunk->skb->data)->cause;

	}



	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));

	/* ASSOC_FAILED will DELETE_TCB. */

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