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authorVlad Yasevich <vladislav.yasevich@hp.com>2009-09-04 18:21:03 -0400
committerVlad Yasevich <vladislav.yasevich@hp.com>2009-09-04 18:21:03 -0400
commitf1751c57f7bb816c9b6b4cb5d79c703aaa7199da (patch)
tree68e75889f4fd4b576f50bd52088c79f7c837323d /net/sctp
parentbe2971438dec2e2d041af4701472a93a7dd03642 (diff)
downloadlwn-f1751c57f7bb816c9b6b4cb5d79c703aaa7199da.tar.gz
lwn-f1751c57f7bb816c9b6b4cb5d79c703aaa7199da.zip
sctp: Catch bogus stream sequence numbers
Since our TSN map is capable of holding at most a 4K chunk gap, there is no way that during this gap, a stream sequence number (unsigned short) can wrap such that the new number is smaller then the next expected one. If such a case is encountered, this is a protocol violation. Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Diffstat (limited to 'net/sctp')
-rw-r--r--net/sctp/sm_statefuns.c28
1 files changed, 26 insertions, 2 deletions
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index a7f18a352364..c8fae1983dd1 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -2891,6 +2891,9 @@ sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep,
goto discard_force;
case SCTP_IERROR_NO_DATA:
goto consume;
+ case SCTP_IERROR_PROTO_VIOLATION:
+ return sctp_sf_abort_violation(ep, asoc, chunk, commands,
+ (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
default:
BUG();
}
@@ -3001,6 +3004,9 @@ sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep,
break;
case SCTP_IERROR_NO_DATA:
goto consume;
+ case SCTP_IERROR_PROTO_VIOLATION:
+ return sctp_sf_abort_violation(ep, asoc, chunk, commands,
+ (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
default:
BUG();
}
@@ -5877,6 +5883,9 @@ static int sctp_eat_data(const struct sctp_association *asoc,
__u32 tsn;
struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
struct sock *sk = asoc->base.sk;
+ u16 ssn;
+ u16 sid;
+ u8 ordered = 0;
data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
@@ -6016,8 +6025,10 @@ static int sctp_eat_data(const struct sctp_association *asoc,
*/
if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
SCTP_INC_STATS(SCTP_MIB_INUNORDERCHUNKS);
- else
+ else {
SCTP_INC_STATS(SCTP_MIB_INORDERCHUNKS);
+ ordered = 1;
+ }
/* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
*
@@ -6027,7 +6038,8 @@ static int sctp_eat_data(const struct sctp_association *asoc,
* with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
* and discard the DATA chunk.
*/
- if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) {
+ sid = ntohs(data_hdr->stream);
+ if (sid >= asoc->c.sinit_max_instreams) {
/* Mark tsn as received even though we drop it */
sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
@@ -6040,6 +6052,18 @@ static int sctp_eat_data(const struct sctp_association *asoc,
return SCTP_IERROR_BAD_STREAM;
}
+ /* Check to see if the SSN is possible for this TSN.
+ * The biggest gap we can record is 4K wide. Since SSNs wrap
+ * at an unsigned short, there is no way that an SSN can
+ * wrap and for a valid TSN. We can simply check if the current
+ * SSN is smaller then the next expected one. If it is, it wrapped
+ * and is invalid.
+ */
+ ssn = ntohs(data_hdr->ssn);
+ if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) {
+ return SCTP_IERROR_PROTO_VIOLATION;
+ }
+
/* Send the data up to the user. Note: Schedule the
* SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
* chunk needs the updated rwnd.