Re: [PATCH 1/3 v2] sctp: check parameter value of length in ERROR chunk

[Shan Wei <shanwei@xxxxxxxxxxxxxx>]

When an endpoint receives ERROR that parameter value is invalid,
send an ABORT to peer with a Protocol Violation error code.


Signed-off-by: Shan Wei <shanwei@xxxxxxxxxxxxxx>
---
v1-v2:
1. As Vlad's suggestion, use chunk->chunk_end to point to end of chunk.
---
 net/sctp/sm_statefuns.c |   31 +++++++++++++++++++++++++++++++
 1 files changed, 31 insertions(+), 0 deletions(-)

diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 24b2cd5..d54038b 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -116,6 +116,13 @@ static sctp_disposition_t sctp_sf_violation_chunklen(
 				     void *arg,
 				     sctp_cmd_seq_t *commands);
 
+static sctp_disposition_t sctp_sf_violation_paramvalue(
+				     const struct sctp_endpoint *ep,
+				     const struct sctp_association *asoc,
+				     const sctp_subtype_t type,
+				     void *arg,
+				     sctp_cmd_seq_t *commands);
+
 static sctp_disposition_t sctp_sf_violation_paramlen(
 				     const struct sctp_endpoint *ep,
 				     const struct sctp_association *asoc,
@@ -3204,6 +3211,7 @@ sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep,
 					sctp_cmd_seq_t *commands)
 {
 	struct sctp_chunk *chunk = arg;
+	sctp_errhdr_t *err;
 
 	if (!sctp_vtag_verify(chunk, asoc))
 		return sctp_sf_pdiscard(ep, asoc, type, arg, commands);
@@ -3213,6 +3221,11 @@ sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep,
 		return sctp_sf_violation_chunklen(ep, asoc, type, arg,
 						  commands);
 
+	sctp_walk_errors(err, chunk->chunk_hdr);
+	if ((void *)err != (void *)chunk->chunk_end)
+		return sctp_sf_violation_paramvalue(ep, asoc, type, arg,
+						    commands);
+
 	sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
 			SCTP_CHUNK(chunk));
 
@@ -4343,6 +4356,24 @@ static sctp_disposition_t sctp_sf_violation_chunklen(
 
 /*
  * Handle a protocol violation when the parameter length is invalid.
+ * "Invalid" length is identified as the parameter value of length
+ * in a Type-Length-Value format is not match the true length of chunk.
+ */
+static sctp_disposition_t sctp_sf_violation_paramvalue(
+				     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 chunk had invalid parameter value:";
+
+	return sctp_sf_abort_violation(ep, asoc, arg, commands, err_str,
+					sizeof(err_str));
+}
+
+/*
+ * Handle a protocol violation when the parameter length is invalid.
  * "Invalid" length is identified as smaller than the minimal length a
  * given parameter can be.
  */
-- 
1.6.3.3
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