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Commit 047a2428 authored by Jerome Forissier's avatar Jerome Forissier Committed by David S. Miller
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[SCTP] Implement Sec 2.41 of SCTP Implementers guide. 



- Fixed sctp_vtag_verify_either() to comply with impguide 2.41 B) and C).
- Make sure vtag is reflected when T-bit is set in SHUTDOWN-COMPLETE sent
  due to an OOTB SHUTDOWN-ACK and in ABORT sent due to an OOTB packet.
- Do not set T-Bit in ABORT chunk in response to INIT.
- Fixed some comments to reflect the new meaning of the T-Bit.

Signed-off-by: default avatarJerome Forissier <jerome.forissier@hp.com>
Signed-off-by: default avatarSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 17337216

include/net/sctp/sm.h

+24 −18
Original line number Diff line number Diff line
@@ -407,32 +407,38 @@ sctp_vtag_verify(const struct sctp_chunk *chunk, 
	return 0;

}



/* Check VTAG of the packet matches the sender's own tag OR its peer's

 * tag and the T bit is set in the Chunk Flags.

/* Check VTAG of the packet matches the sender's own tag and the T bit is

 * not set, OR its peer's tag and the T bit is set in the Chunk Flags.

 */

static inline int

sctp_vtag_verify_either(const struct sctp_chunk *chunk,

			const struct sctp_association *asoc)

{

        /* RFC 2960 Section 8.5.1, sctpimpguide-06 Section 2.13.2

        /* RFC 2960 Section 8.5.1, sctpimpguide Section 2.41

	 *

	 * B) The receiver of a ABORT shall accept the packet if the

	 * Verification Tag field of the packet matches its own tag OR it

	 * is set to its peer's tag and the T bit is set in the Chunk

	 * Flags. Otherwise, the receiver MUST silently discard the packet

	 * B) The receiver of a ABORT MUST accept the packet

	 *    if the Verification Tag field of the packet matches its own tag

	 *    and the T bit is not set

	 *    OR

	 *    it is set to its peer's tag and the T bit is set in the Chunk

	 *    Flags.

	 *    Otherwise, the receiver MUST silently discard the packet

	 *    and take no further action.

	 *

	 * (C) The receiver of a SHUTDOWN COMPLETE shall accept the

	 * packet if the Verification Tag field of the packet

	 * matches its own tag OR it is set to its peer's tag and

	 * the T bit is set in the Chunk Flags.  Otherwise, the

	 * receiver MUST silently discard the packet and take no

	 * further action....

	 *

	 * C) The receiver of a SHUTDOWN COMPLETE shall accept the packet

	 *    if the Verification Tag field of the packet matches its own tag

	 *    and the T bit is not set

	 *    OR

	 *    it is set to its peer's tag and the T bit is set in the Chunk

	 *    Flags.

	 *    Otherwise, the receiver MUST silently discard the packet

	 *    and take no further action.  An endpoint MUST ignore the

	 *    SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.

	 */

        if ((ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag) ||

	    (sctp_test_T_bit(chunk) && (ntohl(chunk->sctp_hdr->vtag)

	    == asoc->c.peer_vtag))) {

        if ((!sctp_test_T_bit(chunk) &&

             (ntohl(chunk->sctp_hdr->vtag) == asoc->c.my_vtag)) ||

	    (sctp_test_T_bit(chunk) &&

	     (ntohl(chunk->sctp_hdr->vtag) == asoc->c.peer_vtag))) {

                return 1;

	}

net/sctp/sm_make_chunk.c

+14 −5
Original line number Diff line number Diff line
@@ -710,7 +710,9 @@ struct sctp_chunk *sctp_make_shutdown_complete( 
	struct sctp_chunk *retval;

	__u8 flags = 0;



	/* Maybe set the T-bit if we have no association. */

	/* Set the T-bit if we have no association (vtag will be

	 * reflected)

	 */

	flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;



	retval = sctp_make_chunk(asoc, SCTP_CID_SHUTDOWN_COMPLETE, flags, 0);
@@ -732,7 +734,7 @@ struct sctp_chunk *sctp_make_shutdown_complete( 
}



/* Create an ABORT.  Note that we set the T bit if we have no

 * association.

 * association, except when responding to an INIT (sctpimpguide 2.41).

 */

struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc,

			      const struct sctp_chunk *chunk,
@@ -741,8 +743,16 @@ struct sctp_chunk *sctp_make_abort(const struct sctp_association *asoc, 
	struct sctp_chunk *retval;

	__u8 flags = 0;



	/* Maybe set the T-bit if we have no association.  */

	flags |= asoc ? 0 : SCTP_CHUNK_FLAG_T;

	/* Set the T-bit if we have no association and 'chunk' is not

	 * an INIT (vtag will be reflected).

	 */

	if (!asoc) {

		if (chunk && chunk->chunk_hdr &&

		    chunk->chunk_hdr->type == SCTP_CID_INIT)

			flags = 0;

		else

			flags = SCTP_CHUNK_FLAG_T;

	}



	retval = sctp_make_chunk(asoc, SCTP_CID_ABORT, flags, hint);
@@ -2744,7 +2754,6 @@ struct sctp_chunk *sctp_make_fwdtsn(const struct sctp_association *asoc, 


	hint = (nstreams + 1) * sizeof(__u32);



	/* Maybe set the T-bit if we have no association.  */

	retval = sctp_make_chunk(asoc, SCTP_CID_FWD_TSN, 0, hint);



	if (!retval)

net/sctp/sm_statefuns.c

+48 −29
Original line number Diff line number Diff line
@@ -126,15 +126,18 @@ sctp_chunk_length_valid(struct sctp_chunk *chunk, 
 * should stop the T2-shutdown timer and remove all knowledge of the

 * association (and thus the association enters the CLOSED state).

 *

 * Verification Tag: 8.5.1(C)

 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.

 * C) Rules for packet carrying SHUTDOWN COMPLETE:

 * ...

 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet if the

 *   Verification Tag field of the packet matches its own tag OR it is

 *   set to its peer's tag and the T bit is set in the Chunk Flags.

 *   Otherwise, the receiver MUST silently discard the packet and take

 *   no further action. An endpoint MUST ignore the SHUTDOWN COMPLETE if

 *   it is not in the SHUTDOWN-ACK-SENT state.

 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet

 *   if the Verification Tag field of the packet matches its own tag and

 *   the T bit is not set

 *   OR

 *   it is set to its peer's tag and the T bit is set in the Chunk

 *   Flags.

 *   Otherwise, the receiver MUST silently discard the packet

 *   and take no further action.  An endpoint MUST ignore the

 *   SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.

 *

 * Inputs

 * (endpoint, asoc, chunk)
@@ -2858,16 +2861,16 @@ sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, 
/*

 * Generate an ABORT in response to a packet.

 *

 * Section: 8.4 Handle "Out of the blue" Packets

 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41

 *

 * 8) The receiver should respond to the sender of the OOTB packet

 *    with an ABORT.  When sending the ABORT, the receiver of the

 *    OOTB packet MUST fill in the Verification Tag field of the

 *    outbound packet with the value found in the Verification Tag

 *    field of the OOTB packet and set the T-bit in the Chunk Flags

 *    to indicate that no TCB was found.  After sending this ABORT,

 *    the receiver of the OOTB packet shall discard the OOTB packet

 *    and take no further action.

 * 8) The receiver should respond to the sender of the OOTB packet with

 *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet

 *    MUST fill in the Verification Tag field of the outbound packet

 *    with the value found in the Verification Tag field of the OOTB

 *    packet and set the T-bit in the Chunk Flags to indicate that the

 *    Verification Tag is reflected.  After sending this ABORT, the

 *    receiver of the OOTB packet shall discard the OOTB packet and take

 *    no further action.

 *

 * Verification Tag:

 *
@@ -2895,6 +2898,10 @@ sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, 
			return SCTP_DISPOSITION_NOMEM;

		}



		/* Reflect vtag if T-Bit is set */

		if (sctp_test_T_bit(abort))

			packet->vtag = ntohl(chunk->sctp_hdr->vtag);



		/* Set the skb to the belonging sock for accounting.  */

		abort->skb->sk = ep->base.sk;
@@ -3026,22 +3033,24 @@ nomem: 
}



/*

 * RFC 2960, 8.4 - Handle "Out of the blue" Packets

 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.

 *

 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should

 *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.

 *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB

 *    packet must fill in the Verification Tag field of the outbound

 *    packet with the Verification Tag received in the SHUTDOWN ACK and

 *    set the T-bit in the Chunk Flags to indicate that no TCB was

 *    found. Otherwise,

 *    set the T-bit in the Chunk Flags to indicate that the Verification

 *    Tag is reflected.

 *

 * 8) The receiver should respond to the sender of the OOTB packet with

 *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet

 *    MUST fill in the Verification Tag field of the outbound packet

 *    with the value found in the Verification Tag field of the OOTB

 *    packet and set the T-bit in the Chunk Flags to indicate that no

 *    TCB was found.  After sending this ABORT, the receiver of the OOTB

 *    packet shall discard the OOTB packet and take no further action.

 *    packet and set the T-bit in the Chunk Flags to indicate that the

 *    Verification Tag is reflected.  After sending this ABORT, the

 *    receiver of the OOTB packet shall discard the OOTB packet and take

 *    no further action.

 */

sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep,

				const struct sctp_association *asoc,
@@ -3090,13 +3099,15 @@ sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, 
/*

 * Handle an "Out of the blue" SHUTDOWN ACK.

 *

 * Section: 8.4 5)

 * Section: 8.4 5, sctpimpguide 2.41.

 *

 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should

 *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.

 *   When sending the SHUTDOWN COMPLETE, the receiver of the OOTB packet

 *   must fill in the Verification Tag field of the outbound packet with

 *   the Verification Tag received in the SHUTDOWN ACK and set the

 *   T-bit in the Chunk Flags to indicate that no TCB was found.

 *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB

 *    packet must fill in the Verification Tag field of the outbound

 *    packet with the Verification Tag received in the SHUTDOWN ACK and

 *    set the T-bit in the Chunk Flags to indicate that the Verification

 *    Tag is reflected.

 *

 * Inputs

 * (endpoint, asoc, type, arg, commands)
@@ -3128,6 +3139,10 @@ static sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, 
			return SCTP_DISPOSITION_NOMEM;

		}



		/* Reflect vtag if T-Bit is set */

		if (sctp_test_T_bit(shut))

			packet->vtag = ntohl(chunk->sctp_hdr->vtag);



		/* Set the skb to the belonging sock for accounting.  */

		shut->skb->sk = ep->base.sk;
@@ -3591,7 +3606,6 @@ sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, 
 *

 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST

 *    silently discard the OOTB packet and take no further action.

 *    Otherwise,

 *

 * Verification Tag: No verification necessary

 *
@@ -4961,6 +4975,11 @@ static struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, 
			sctp_ootb_pkt_free(packet);

			return NULL;

		}



		/* Reflect vtag if T-Bit is set */

		if (sctp_test_T_bit(abort))

			packet->vtag = ntohl(chunk->sctp_hdr->vtag);



		/* Add specified error causes, i.e., payload, to the

		 * end of the chunk.

		 */