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 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