sctp: free cmd->obj.chunk for the unprocessed SCTP_CMD_REPLY

This patch is to fix a memleak caused by no place to free cmd->obj.chunk
for the unprocessed SCTP_CMD_REPLY. This issue occurs when failing to
process a cmd while there're still SCTP_CMD_REPLY cmds on the cmd seq
with an allocated chunk in cmd->obj.chunk.

So fix it by freeing cmd->obj.chunk for each SCTP_CMD_REPLY cmd left on
the cmd seq when any cmd returns error. While at it, also remove 'nomem'
label.

Reported-by: syzbot+107c4aff5f392bf1517f@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index acd737d4c0e0a938895ed10fc8aa39e3f908b64f..834e9f82afedc47e99fab3cd140d1d82795e93ac 100644 (file)
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -1363,8 +1363,10 @@ static int sctp_cmd_interpreter(enum sctp_event_type event_type,
                        /* Generate an INIT ACK chunk.  */
                        new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC,
                                                     0);
-                       if (!new_obj)
-                               goto nomem;
+                       if (!new_obj) {
+                               error = -ENOMEM;
+                               break;
+                       }
 
                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
                                        SCTP_CHUNK(new_obj));
@@ -1386,7 +1388,8 @@ static int sctp_cmd_interpreter(enum sctp_event_type event_type,
                        if (!new_obj) {
                                if (cmd->obj.chunk)
                                        sctp_chunk_free(cmd->obj.chunk);
-                               goto nomem;
+                               error = -ENOMEM;
+                               break;
                        }
                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
                                        SCTP_CHUNK(new_obj));
@@ -1433,8 +1436,10 @@ static int sctp_cmd_interpreter(enum sctp_event_type event_type,
 
                        /* Generate a SHUTDOWN chunk.  */
                        new_obj = sctp_make_shutdown(asoc, chunk);
-                       if (!new_obj)
-                               goto nomem;
+                       if (!new_obj) {
+                               error = -ENOMEM;
+                               break;
+                       }
                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
                                        SCTP_CHUNK(new_obj));
                        break;
@@ -1770,11 +1775,17 @@ static int sctp_cmd_interpreter(enum sctp_event_type event_type,
                        break;
                }
 
-               if (error)
+               if (error) {
+                       cmd = sctp_next_cmd(commands);
+                       while (cmd) {
+                               if (cmd->verb == SCTP_CMD_REPLY)
+                                       sctp_chunk_free(cmd->obj.chunk);
+                               cmd = sctp_next_cmd(commands);
+                       }
                        break;
+               }
        }
 
-out:
        /* If this is in response to a received chunk, wait until
         * we are done with the packet to open the queue so that we don't
         * send multiple packets in response to a single request.
@@ -1789,7 +1800,4 @@ out:
                sp->data_ready_signalled = 0;
 
        return error;
-nomem:
-       error = -ENOMEM;
-       goto out;
 }