Commit eb96d5c9 authored by Andy Adamson's avatar Andy Adamson Committed by Trond Myklebust
Browse files

SUNRPC handle EKEYEXPIRED in call_refreshresult 



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: default avatarAndy Adamson <andros@netapp.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 620038f6

fs/nfs/nfs3proc.c

+3 −3
Original line number Diff line number Diff line
@@ -24,14 +24,14 @@ 


#define NFSDBG_FACILITY		NFSDBG_PROC



/* A wrapper to handle the EJUKEBOX and EKEYEXPIRED error messages */

/* A wrapper to handle the EJUKEBOX error messages */

static int

nfs3_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)

{

	int res;

	do {

		res = rpc_call_sync(clnt, msg, flags);

		if (res != -EJUKEBOX && res != -EKEYEXPIRED)

		if (res != -EJUKEBOX)

			break;

		freezable_schedule_timeout_killable(NFS_JUKEBOX_RETRY_TIME);

		res = -ERESTARTSYS;
@@ -44,7 +44,7 @@ nfs3_rpc_wrapper(struct rpc_clnt *clnt, struct rpc_message *msg, int flags) 
static int

nfs3_async_handle_jukebox(struct rpc_task *task, struct inode *inode)

{

	if (task->tk_status != -EJUKEBOX && task->tk_status != -EKEYEXPIRED)

	if (task->tk_status != -EJUKEBOX)

		return 0;

	if (task->tk_status == -EJUKEBOX)

		nfs_inc_stats(inode, NFSIOS_DELAY);

fs/nfs/nfs4filelayout.c

+0 −1
Original line number Diff line number Diff line
@@ -179,7 +179,6 @@ static int filelayout_async_handle_error(struct rpc_task *task, 
		break;

	case -NFS4ERR_DELAY:

	case -NFS4ERR_GRACE:

	case -EKEYEXPIRED:

		rpc_delay(task, FILELAYOUT_POLL_RETRY_MAX);

		break;

	case -NFS4ERR_RETRY_UNCACHED_REP:

fs/nfs/nfs4proc.c

+0 −18
Original line number Diff line number Diff line
@@ -333,7 +333,6 @@ static int nfs4_handle_exception(struct nfs_server *server, int errorcode, struc 
			}

		case -NFS4ERR_GRACE:

		case -NFS4ERR_DELAY:

		case -EKEYEXPIRED:

			ret = nfs4_delay(server->client, &exception->timeout);

			if (ret != 0)

				break;
@@ -1343,13 +1342,6 @@ int nfs4_open_delegation_recall(struct nfs_open_context *ctx, struct nfs4_state 
				nfs_inode_find_state_and_recover(state->inode,

						stateid);

				nfs4_schedule_stateid_recovery(server, state);

			case -EKEYEXPIRED:

				/*

				 * User RPCSEC_GSS context has expired.

				 * We cannot recover this stateid now, so

				 * skip it and allow recovery thread to

				 * proceed.

				 */

			case -ENOMEM:

				err = 0;

				goto out;
@@ -3946,7 +3938,6 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server, 
		case -NFS4ERR_DELAY:

			nfs_inc_server_stats(server, NFSIOS_DELAY);

		case -NFS4ERR_GRACE:

		case -EKEYEXPIRED:

			rpc_delay(task, NFS4_POLL_RETRY_MAX);

			task->tk_status = 0;

			return -EAGAIN;
@@ -4946,15 +4937,6 @@ int nfs4_lock_delegation_recall(struct nfs4_state *state, struct file_lock *fl) 
				nfs4_schedule_stateid_recovery(server, state);

				err = 0;

				goto out;

			case -EKEYEXPIRED:

				/*

				 * User RPCSEC_GSS context has expired.

				 * We cannot recover this stateid now, so

				 * skip it and allow recovery thread to

				 * proceed.

				 */

				err = 0;

				goto out;

			case -ENOMEM:

			case -NFS4ERR_DENIED:

				/* kill_proc(fl->fl_pid, SIGLOST, 1); */

fs/nfs/nfs4state.c

+0 −23
Original line number Diff line number Diff line
@@ -1437,14 +1437,6 @@ restart: 
				/* Mark the file as being 'closed' */

				state->state = 0;

				break;

			case -EKEYEXPIRED:

				/*

				 * User RPCSEC_GSS context has expired.

				 * We cannot recover this stateid now, so

				 * skip it and allow recovery thread to

				 * proceed.

				 */

				break;

			case -NFS4ERR_ADMIN_REVOKED:

			case -NFS4ERR_STALE_STATEID:

			case -NFS4ERR_BAD_STATEID:
@@ -1597,14 +1589,6 @@ static void nfs4_state_start_reclaim_nograce(struct nfs_client *clp) 
	nfs4_state_mark_reclaim_helper(clp, nfs4_state_mark_reclaim_nograce);

}



static void nfs4_warn_keyexpired(const char *s)

{

	printk_ratelimited(KERN_WARNING "Error: state manager"

			" encountered RPCSEC_GSS session"

			" expired against NFSv4 server %s.\n",

			s);

}



static int nfs4_recovery_handle_error(struct nfs_client *clp, int error)

{

	switch (error) {
@@ -1638,10 +1622,6 @@ static int nfs4_recovery_handle_error(struct nfs_client *clp, int error) 
		case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:

			set_bit(NFS4CLNT_BIND_CONN_TO_SESSION, &clp->cl_state);

			break;

		case -EKEYEXPIRED:

			/* Nothing we can do */

			nfs4_warn_keyexpired(clp->cl_hostname);

			break;

		default:

			dprintk("%s: failed to handle error %d for server %s\n",

					__func__, error, clp->cl_hostname);
@@ -1758,8 +1738,6 @@ static int nfs4_handle_reclaim_lease_error(struct nfs_client *clp, int status) 
		dprintk("%s: exit with error %d for server %s\n",

				__func__, -EPROTONOSUPPORT, clp->cl_hostname);

		return -EPROTONOSUPPORT;

	case -EKEYEXPIRED:

		nfs4_warn_keyexpired(clp->cl_hostname);

	case -NFS4ERR_NOT_SAME: /* FixMe: implement recovery

				 * in nfs4_exchange_id */

	default:
@@ -1912,7 +1890,6 @@ again: 
		break;



	case -EKEYEXPIRED:

		nfs4_warn_keyexpired(clp->cl_hostname);

	case -NFS4ERR_NOT_SAME: /* FixMe: implement recovery

				 * in nfs4_exchange_id */

		status = -EKEYEXPIRED;

fs/nfs/proc.c

+0 −43
Original line number Diff line number Diff line
@@ -46,39 +46,6 @@ 


#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.

 */
@@ -364,8 +331,6 @@ 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;

}
@@ -385,8 +350,6 @@ 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;
@@ -642,9 +605,6 @@ static int nfs_read_done(struct rpc_task *task, struct nfs_read_data *data) 
{

	struct inode *inode = data->header->inode;



	if (nfs_async_handle_expired_key(task))

		return -EAGAIN;



	nfs_invalidate_atime(inode);

	if (task->tk_status >= 0) {

		nfs_refresh_inode(inode, data->res.fattr);
@@ -671,9 +631,6 @@ static int nfs_write_done(struct rpc_task *task, struct nfs_write_data *data) 
{

	struct inode *inode = data->header->inode;



	if (nfs_async_handle_expired_key(task))

		return -EAGAIN;



	if (task->tk_status >= 0)

		nfs_post_op_update_inode_force_wcc(inode, data->res.fattr);

	return 0;

CRA Git | Maintained and supported by SUSTech CRA and CCSE