sctp: Fix kernel panic while process protocol violation parameter

Since call to function sctp_sf_abort_violation() need paramter 'arg' with
'struct sctp_chunk' type, it will read the chunk type and chunk length from
the chunk_hdr member of chunk. But call to sctp_sf_violation_paramlen()
always with 'struct sctp_paramhdr' type's parameter, it will be passed to
sctp_sf_abort_violation(). This may cause kernel panic.

   sctp_sf_violation_paramlen()
     |-- sctp_sf_abort_violation()
        |-- sctp_make_abort_violation()

This patch fixed this problem. This patch also fix two place which called
sctp_sf_violation_paramlen() with wrong paramter type.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 37 insertions, 11 deletions

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 8848d329aa2..7c622af2ce5 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -119,7 +119,7 @@ static sctp_disposition_t sctp_sf_violation_paramlen(
 				     const struct sctp_endpoint *ep,
 				     const struct sctp_association *asoc,
 				     const sctp_subtype_t type,
-				     void *arg,
+				     void *arg, void *ext,
 				     sctp_cmd_seq_t *commands);
 
 static sctp_disposition_t sctp_sf_violation_ctsn(
@@ -3425,7 +3425,7 @@ sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
 	addr_param = (union sctp_addr_param *)hdr->params;
 	length = ntohs(addr_param->p.length);
 	if (length < sizeof(sctp_paramhdr_t))
-		return sctp_sf_violation_paramlen(ep, asoc, type,
+		return sctp_sf_violation_paramlen(ep, asoc, type, arg,
 			   (void *)addr_param, commands);
 
 	/* Verify the ASCONF chunk before processing it. */
@@ -3433,8 +3433,8 @@ sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep,
 			    (sctp_paramhdr_t *)((void *)addr_param + length),
 			    (void *)chunk->chunk_end,
 			    &err_param))
-		return sctp_sf_violation_paramlen(ep, asoc, type,
-						  (void *)&err_param, commands);
+		return sctp_sf_violation_paramlen(ep, asoc, type, arg,
+						  (void *)err_param, commands);
 
 	/* ADDIP 5.2 E1) Compare the value of the serial number to the value
 	 * the endpoint stored in a new association variable
@@ -3542,8 +3542,8 @@ sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
 	    (sctp_paramhdr_t *)addip_hdr->params,
 	    (void *)asconf_ack->chunk_end,
 	    &err_param))
-		return sctp_sf_violation_paramlen(ep, asoc, type,
-			   (void *)&err_param, commands);
+		return sctp_sf_violation_paramlen(ep, asoc, type, arg,
+			   (void *)err_param, commands);
 
 	if (last_asconf) {
 		addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
@@ -4240,12 +4240,38 @@ static sctp_disposition_t sctp_sf_violation_paramlen(
 				     const struct sctp_endpoint *ep,
 				     const struct sctp_association *asoc,
 				     const sctp_subtype_t type,
-				     void *arg,
-				     sctp_cmd_seq_t *commands) {
-	static const char err_str[] = "The following parameter had invalid length:";
+				     void *arg, void *ext,
+				     sctp_cmd_seq_t *commands)
+{
+	struct sctp_chunk *chunk =  arg;
+	struct sctp_paramhdr *param = ext;
+	struct sctp_chunk *abort = NULL;
 
-	return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
-					sizeof(err_str));
+	if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
+		goto discard;
+
+	/* Make the abort chunk. */
+	abort = sctp_make_violation_paramlen(asoc, chunk, param);
+	if (!abort)
+		goto nomem;
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
+	SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
+
+	sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
+			SCTP_ERROR(ECONNABORTED));
+	sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
+			SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
+	SCTP_DEC_STATS(SCTP_MIB_CURRESTAB);
+
+discard:
+	sctp_sf_pdiscard(ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
+
+	SCTP_INC_STATS(SCTP_MIB_ABORTEDS);
+
+	return SCTP_DISPOSITION_ABORT;
+nomem:
+	return SCTP_DISPOSITION_NOMEM;
 }
 
 /* Handle a protocol violation when the peer trying to advance the