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>

3 files changed, 64 insertions, 24 deletions

diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index 24811732bdb2..029a54a02396 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -227,6 +227,9 @@ struct sctp_chunk *sctp_make_abort_violation(const struct sctp_association *,
                                    const struct sctp_chunk *,
                                    const __u8 *,
                                    const size_t );
+struct sctp_chunk *sctp_make_violation_paramlen(const struct sctp_association *,
+                                   const struct sctp_chunk *,
+                                   struct sctp_paramhdr *);
 struct sctp_chunk *sctp_make_heartbeat(const struct sctp_association *,
                                   const struct sctp_transport *,
                                   const void *payload,
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;
 }
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 8848d329aa2c..7c622af2ce55 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