Commit 9fcb95a1 authored by Wei Yongjun's avatar Wei Yongjun Committed by David S. Miller
Browse files

sctp: Avoid memory overflow while FWD-TSN chunk is received with bad stream ID 



If FWD-TSN chunk is received with bad stream ID, the sctp will not do the
validity check, this may cause memory overflow when overwrite the TSN of
the stream ID.

The FORWARD-TSN chunk is like this:

FORWARD-TSN chunk
  Type                       = 192
  Flags                      = 0
  Length                     = 172
  NewTSN                     = 99
  Stream                     = 10000
  StreamSequence             = 0xFFFF

This patch fix this problem by discard the chunk if stream ID is not
less than MIS.

Signed-off-by: default avatarWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aea3c5c0

net/sctp/sm_statefuns.c

+14 −0
Original line number Original line Diff line number Diff line
@@ -3689,6 +3689,7 @@ sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 
{

{

	struct sctp_chunk *chunk = arg;

	struct sctp_chunk *chunk = arg;

	struct sctp_fwdtsn_hdr *fwdtsn_hdr;

	struct sctp_fwdtsn_hdr *fwdtsn_hdr;

	struct sctp_fwdtsn_skip *skip;

	__u16 len;

	__u16 len;

	__u32 tsn;

	__u32 tsn;
@@ -3718,6 +3719,12 @@ sctp_disposition_t sctp_sf_eat_fwd_tsn(const struct sctp_endpoint *ep, 
	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)

	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)

		goto discard_noforce;

		goto discard_noforce;





	/* Silently discard the chunk if stream-id is not valid */

	sctp_walk_fwdtsn(skip, chunk) {

		if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)

			goto discard_noforce;

	}



	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));

	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));

	if (len > sizeof(struct sctp_fwdtsn_hdr))

	if (len > sizeof(struct sctp_fwdtsn_hdr))

		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,

		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
@@ -3749,6 +3756,7 @@ sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 
{

{

	struct sctp_chunk *chunk = arg;

	struct sctp_chunk *chunk = arg;

	struct sctp_fwdtsn_hdr *fwdtsn_hdr;

	struct sctp_fwdtsn_hdr *fwdtsn_hdr;

	struct sctp_fwdtsn_skip *skip;

	__u16 len;

	__u16 len;

	__u32 tsn;

	__u32 tsn;
@@ -3778,6 +3786,12 @@ sctp_disposition_t sctp_sf_eat_fwd_tsn_fast( 
	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)

	if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)

		goto gen_shutdown;

		goto gen_shutdown;





	/* Silently discard the chunk if stream-id is not valid */

	sctp_walk_fwdtsn(skip, chunk) {

		if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)

			goto gen_shutdown;

	}



	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));

	sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));

	if (len > sizeof(struct sctp_fwdtsn_hdr))

	if (len > sizeof(struct sctp_fwdtsn_hdr))

		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,

		sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,

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