svcrpc: close connection if client sends short packet

If the client sents a record too short to contain even the beginning of
the rpc header, then just close the connection.

The current code drops the record data and continues.  I don't see the
point.  It's a hopeless situation and simpler just to cut off the
connection completely.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 7 insertions, 14 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 1955e1a1e390..62ff7c5c09c2 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -955,6 +955,9 @@ static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
                 }
         }
 
+        if (svsk->sk_reclen < 8)
+                goto err_delete; /* client is nuts. */
+
         /* Check whether enough data is available */
         len = svc_recv_available(svsk);
         if (len < 0)
@@ -1058,20 +1061,10 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
         vec[0] = rqstp->rq_arg.head[0];
         vlen = PAGE_SIZE;
 
-        /*
-         * We have enough data for the whole tcp record. Let's try and read the
-         * first 8 bytes to get the xid and the call direction. We can use this
-         * to figure out if this is a call or a reply to a callback. If
-         * sk_reclen is < 8 (xid and calldir), then this is a malformed packet.
-         * In that case, don't bother with the calldir and just read the data.
-         * It will be rejected in svc_process.
-         */
-        if (len >= 8) {
-                len = svc_process_calldir(svsk, rqstp, &req, vec);
-                if (len < 0)
-                        goto err_again;
-                vlen -= 8;
-        }
+        len = svc_process_calldir(svsk, rqstp, &req, vec);
+        if (len < 0)
+                goto err_again;
+        vlen -= 8;
 
         pnum = 1;
         while (vlen < svsk->sk_reclen - 8) {