sunrpc: fix refcount leak for rpc auth modules

stable inclusion
from linux-4.19.183
commit 98982cf7997414245477ffa90c9cdf8492c0b4bc

--------------------------------

commit f1442d63 upstream.

If an auth module's accept op returns SVC_CLOSE, svc_process_common()
enters a call path that does not call svc_authorise() before leaving the
function, and thus leaks a reference on the auth module's refcount. Hence,
make sure calls to svc_authenticate() and svc_authorise() are paired for
all call paths, to make sure rpc auth modules can be unloaded.
Signed-off-by: NDaniel Kobras <kobras@puzzle-itc.de>
Fixes: 4d712ef1 ("svcauth_gss: Close connection when dropping an incoming message")
Link: https://lore.kernel.org/linux-nfs/3F1B347F-B809-478F-A1E9-0BE98E22B0F0@oracle.com/T/#tSigned-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

net/sunrpc/svc.c

@@ -1330,7 +1330,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 
  sendit:
 	if (svc_authorise(rqstp))
-		goto close;
+		goto close_xprt;
 	return 1;		/* Caller can now send it */
 
  dropit:
@@ -1339,6 +1339,8 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 	return 0;
 
  close:
+	svc_authorise(rqstp);
+close_xprt:
 	if (rqstp->rq_xprt && test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
 		svc_close_xprt(rqstp->rq_xprt);
 	dprintk("svc: svc_process close\n");
@@ -1347,7 +1349,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 err_short_len:
 	svc_printk(rqstp, "short len %zd, dropping request\n",
 			argv->iov_len);
-	goto close;
+	goto close_xprt;
 
 err_bad_rpc:
 	serv->sv_stats->rpcbadfmt++;