svcauth_gss: Close connection when dropping an incoming message

S5.3.3.1 of RFC 2203 requires that an incoming GSS-wrapped message
whose sequence number lies outside the current window is dropped.
The rationale is:

  The reason for discarding requests silently is that the server
  is unable to determine if the duplicate or out of range request
  was due to a sequencing problem in the client, network, or the
  operating system, or due to some quirk in routing, or a replay
  attack by an intruder.  Discarding the request allows the client
  to recover after timing out, if indeed the duplication was
  unintentional or well intended.

However, clients may rely on the server dropping the connection to
indicate that a retransmit is needed. Without a connection reset, a
client can wait forever without retransmitting, and the workload
just stops dead. I've reproduced this behavior by running xfstests
generic/323 on an NFSv4.0 mount with proto=rdma and sec=krb5i.

To address this issue, have the server close the connection when it
silently discards an incoming message due to a GSS sequence number
problem.

There are a few other places where the server will never reply.
Change those spots in a similar fashion.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 45662d7f0943c671297955e0c44e7632460c2c68..886e9d381771ab8c05ed514a399a089c106b2282 100644 (file)
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -1548,7 +1548,7 @@ complete:
        ret = SVC_COMPLETE;
        goto out;
 drop:
-       ret = SVC_DROP;
+       ret = SVC_CLOSE;
 out:
        if (rsci)
                cache_put(&rsci->h, sn->rsc_cache);

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 7c8070ec93c8a74b9735e7b388c2de404141a0df..75f290bddca1bbfd5c8a9db9bab1ac3d231f9ada 100644 (file)
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1155,8 +1155,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
        case SVC_DENIED:
                goto err_bad_auth;
        case SVC_CLOSE:
-               if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
-                       svc_close_xprt(rqstp->rq_xprt);
+               goto close;
        case SVC_DROP:
                goto dropit;
        case SVC_COMPLETE:
@@ -1246,7 +1245,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 
  sendit:
        if (svc_authorise(rqstp))
-               goto dropit;
+               goto close;
        return 1;               /* Caller can now send it */
 
  dropit:
@@ -1254,11 +1253,16 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
        dprintk("svc: svc_process dropit\n");
        return 0;
 
+ close:
+       if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
+               svc_close_xprt(rqstp->rq_xprt);
+       dprintk("svc: svc_process close\n");
+       return 0;
+
 err_short_len:
        svc_printk(rqstp, "short len %Zd, dropping request\n",
                        argv->iov_len);
-
-       goto dropit;                    /* drop request */
+       goto close;
 
 err_bad_rpc:
        serv->sv_stats->rpcbadfmt++;