NFS: Fix infinite loop in gss_create_upcall()

There can be an infinite loop if gss_create_upcall() is called without
the userspace program running.  To prevent this, we return -EACCES if
we notice that pipe_version hasn't changed (indicating that the pipe
has not been opened).

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 8 insertions, 5 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 9bf41eab3e46..8a03ee0689f3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2224,8 +2224,9 @@ static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
 
         for (i = 0; i < len; i++) {
                 status = nfs4_lookup_root_sec(server, fhandle, info, flav_array[i]);
-                if (status != -EPERM)
-                        break;
+                if (status == -EPERM || status == -EACCES)
+                        continue;
+                break;
         }
         if (status == 0)
                 status = nfs4_server_capabilities(server, fhandle);
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index f3914d0c5079..339ba64cce1e 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -520,7 +520,7 @@ gss_refresh_upcall(struct rpc_task *task)
                 warn_gssd();
                 task->tk_timeout = 15*HZ;
                 rpc_sleep_on(&pipe_version_rpc_waitqueue, task, NULL);
-                return 0;
+                return -EAGAIN;
         }
         if (IS_ERR(gss_msg)) {
                 err = PTR_ERR(gss_msg);
@@ -563,10 +563,12 @@ retry:
         if (PTR_ERR(gss_msg) == -EAGAIN) {
                 err = wait_event_interruptible_timeout(pipe_version_waitqueue,
                                 pipe_version >= 0, 15*HZ);
+                if (pipe_version < 0) {
+                        warn_gssd();
+                        err = -EACCES;
+                }
                 if (err)
                         goto out;
-                if (pipe_version < 0)
-                        warn_gssd();
                 goto retry;
         }
         if (IS_ERR(gss_msg)) {