SUNRPC handle EKEYEXPIRED in call_refreshresult

commit eb96d5c97b0825d542e9c4ba5e0a22b519355166 upstream.

Currently, when an RPCSEC_GSS context has expired or is non-existent
and the users (Kerberos) credentials have also expired or are non-existent,
the client receives the -EKEYEXPIRED error and tries to refresh the context
forever.  If an application is performing I/O, or other work against the share,
the application hangs, and the user is not prompted to refresh/establish their
credentials. This can result in a denial of service for other users.

Users are expected to manage their Kerberos credential lifetimes to mitigate
this issue.

Move the -EKEYEXPIRED handling into the RPC layer. Try tk_cred_retry number
of times to refresh the gss_context, and then return -EACCES to the application.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[bwh: Backported to 3.2:
 - Adjust context
 - Drop change to nfs4_handle_reclaim_lease_error()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 0 insertions, 43 deletions

diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index b63b6f4d14fb..af9947e35fcb 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -47,39 +47,6 @@
 #define NFSDBG_FACILITY		NFSDBG_PROC
 
 /*
- * wrapper to handle the -EKEYEXPIRED error message. This should generally
- * only happen if using krb5 auth and a user's TGT expires. NFSv2 doesn't
- * support the NFSERR_JUKEBOX error code, but we handle this situation in the
- * same way that we handle that error with NFSv3.
- */
-static int
-nfs_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
-{
-	int res;
-	do {
-		res = rpc_call_sync(clnt, msg, flags);
-		if (res != -EKEYEXPIRED)
-			break;
-		freezable_schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);
-		res = -ERESTARTSYS;
-	} while (!fatal_signal_pending(current));
-	return res;
-}
-
-#define rpc_call_sync(clnt, msg, flags)	nfs_rpc_wrapper(clnt, msg, flags)
-
-static int
-nfs_async_handle_expired_key(struct rpc_task *task)
-{
-	if (task->tk_status != -EKEYEXPIRED)
-		return 0;
-	task->tk_status = 0;
-	rpc_restart_call(task);
-	rpc_delay(task, NFS_JUKEBOX_RETRY_TIME);
-	return 1;
-}
-
-/*
  * Bare-bones access to getattr: this is for nfs_read_super.
  */
 static int
@@ -365,8 +332,6 @@ static void nfs_proc_unlink_rpc_prepare(struct rpc_task *task, struct nfs_unlink
 
 static int nfs_proc_unlink_done(struct rpc_task *task, struct inode *dir)
 {
-	if (nfs_async_handle_expired_key(task))
-		return 0;
 	nfs_mark_for_revalidate(dir);
 	return 1;
 }
@@ -386,8 +351,6 @@ static int
 nfs_proc_rename_done(struct rpc_task *task, struct inode *old_dir,
 		     struct inode *new_dir)
 {
-	if (nfs_async_handle_expired_key(task))
-		return 0;
 	nfs_mark_for_revalidate(old_dir);
 	nfs_mark_for_revalidate(new_dir);
 	return 1;
@@ -641,9 +604,6 @@ nfs_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
 
 static int nfs_read_done(struct rpc_task *task, struct nfs_read_data *data)
 {
-	if (nfs_async_handle_expired_key(task))
-		return -EAGAIN;
-
 	nfs_invalidate_atime(data->inode);
 	if (task->tk_status >= 0) {
 		nfs_refresh_inode(data->inode, data->res.fattr);
@@ -668,9 +628,6 @@ static void nfs_proc_read_rpc_prepare(struct rpc_task *task, struct nfs_read_dat
 
 static int nfs_write_done(struct rpc_task *task, struct nfs_write_data *data)
 {
-	if (nfs_async_handle_expired_key(task))
-		return -EAGAIN;
-
 	if (task->tk_status >= 0)
 		nfs_post_op_update_inode_force_wcc(data->inode, data->res.fattr);
 	return 0;