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, 24 insertions, 13 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index b599cbba4fbe..d68869f966c3 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -1012,6 +1012,29 @@ end:
 	return retval;
 }
 
+struct sctp_chunk *sctp_make_violation_paramlen(
+	const struct sctp_association *asoc,
+	const struct sctp_chunk *chunk,
+	struct sctp_paramhdr *param)
+{
+	struct sctp_chunk *retval;
+	static const char error[] = "The following parameter had invalid length:";
+	size_t payload_len = sizeof(error) + sizeof(sctp_errhdr_t) +
+				sizeof(sctp_paramhdr_t);
+
+	retval = sctp_make_abort(asoc, chunk, payload_len);
+	if (!retval)
+		goto nodata;
+
+	sctp_init_cause(retval, SCTP_ERROR_PROTO_VIOLATION,
+			sizeof(error) + sizeof(sctp_paramhdr_t));
+	sctp_addto_chunk(retval, sizeof(error), error);
+	sctp_addto_param(retval, sizeof(sctp_paramhdr_t), param);
+
+nodata:
+	return retval;
+}
+
 /* Make a HEARTBEAT chunk.  */
 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *asoc,
 				  const struct sctp_transport *transport,
@@ -1782,11 +1805,6 @@ static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
 					const struct sctp_chunk *chunk,
 					struct sctp_chunk **errp)
 {
-	static const char error[] = "The following parameter had invalid length:";
-	size_t		payload_len = WORD_ROUND(sizeof(error)) +
-						sizeof(sctp_paramhdr_t);
-
-
 	/* This is a fatal error.  Any accumulated non-fatal errors are
 	 * not reported.
 	 */
@@ -1794,14 +1812,7 @@ static int sctp_process_inv_paramlength(const struct sctp_association *asoc,
 		sctp_chunk_free(*errp);
 
 	/* Create an error chunk and fill it in with our payload. */
-	*errp = sctp_make_op_error_space(asoc, chunk, payload_len);
-
-	if (*errp) {
-		sctp_init_cause(*errp, SCTP_ERROR_PROTO_VIOLATION,
-				sizeof(error) + sizeof(sctp_paramhdr_t));
-		sctp_addto_chunk(*errp, sizeof(error), error);
-		sctp_addto_param(*errp, sizeof(sctp_paramhdr_t), param);
-	}
+	*errp = sctp_make_violation_paramlen(asoc, chunk, param);
 
 	return 0;
 }