[PATCH] rpcgss : RPC_GSS_PROC_DESTROY request will get a bad rpc reply message

[Wei Yongjun]

If I send a RPC_GSS_PROC_DESTROY message to NFSv4 server, I will reply 
us a bad rpc reply which without an authentication verifier in it.
Maybe this patch is needed.

Send/recv packets as following:

send:

RemoteProcedureCall
    xid
    rpcvers = 2
    prog = 100003
    vers = 4
    proc = 0
    cred = AUTH_GSS
        version = 1
        gss_proc = 3 (RPCSEC_GSS_DESTROY)
        service  = 1 (RPC_GSS_SVC_NONE)
    verf = AUTH_GSS
        checksum

reply:

RemoteProcedureReply
    xid
    msg_type
    reply_stat
    accepted_reply

Signed-off-by: Wei Yongjun <yjwei at cn.fujitsu.com>

--- net/sunrpc/auth_gss/svcauth_gss.c.orig	2007-04-09 08:17:55.000000000 -0400
+++ net/sunrpc/auth_gss/svcauth_gss.c	2007-04-09 08:18:37.000000000 -0400
@@ -1088,6 +1088,8 @@ svcauth_gss_accept(struct svc_rqst *rqst
 		}
 		goto complete;
 	case RPC_GSS_PROC_DESTROY:
+		if (gss_write_verf(rqstp, rsci->mechctx, gc->gc_seq))
+			goto auth_err;
 		set_bit(CACHE_NEGATIVE, &rsci->h.flags);
 		if (resv->iov_len + 4 > PAGE_SIZE)
 			goto drop;