[PATCH 3.16 272/370] svcrpc: fix oops in absence of krb5 module

Ben Hutchings
2017-03-10T13:39:11Z

From: "J. Bruce Fields" <bfields@redhat.com>

commit 034dd34ff4916ec1f8f74e39ca3efb04eab2f791 upstream.

Olga Kornievskaia says: "I ran into this oops in the nfsd (below)
(4.10-rc3 kernel). To trigger this I had a client (unsuccessfully) try
to mount the server with krb5 where the server doesn't have the
rpcsec_gss_krb5 module built."

The problem is that rsci.cred is copied from a svc_cred structure that
gss_proxy didn't properly initialize. Fix that.

[120408.542387] general protection fault: 0000 [#1] SMP
...
[120408.565724] CPU: 0 PID: 3601 Comm: nfsd Not tainted 4.10.0-rc3+ #16
[120408.567037] Hardware name: VMware, Inc. VMware Virtual =
Platform/440BX Desktop Reference Platform, BIOS 6.00 07/02/2015
[120408.569225] task: ffff8800776f95c0 task.stack: ffffc90003d58000
[120408.570483] RIP: 0010:gss_mech_put+0xb/0x20 [auth_rpcgss]
...
[120408.584946] ? rsc_free+0x55/0x90 [auth_rpcgss]
[120408.585901] gss_proxy_save_rsc+0xb2/0x2a0 [auth_rpcgss]
[120408.587017] svcauth_gss_proxy_init+0x3cc/0x520 [auth_rpcgss]
[120408.588257] ? __enqueue_entity+0x6c/0x70
[120408.589101] svcauth_gss_accept+0x391/0xb90 [auth_rpcgss]
[120408.590212] ? try_to_wake_up+0x4a/0x360
[120408.591036] ? wake_up_process+0x15/0x20
[120408.592093] ? svc_xprt_do_enqueue+0x12e/0x2d0 [sunrpc]
[120408.593177] svc_authenticate+0xe1/0x100 [sunrpc]
[120408.594168] svc_process_common+0x203/0x710 [sunrpc]
[120408.595220] svc_process+0x105/0x1c0 [sunrpc]
[120408.596278] nfsd+0xe9/0x160 [nfsd]
[120408.597060] kthread+0x101/0x140
[120408.597734] ? nfsd_destroy+0x60/0x60 [nfsd]
[120408.598626] ? kthread_park+0x90/0x90
[120408.599448] ret_from_fork+0x22/0x30

Fixes: 1d658336b05f "SUNRPC: Add RPC based upcall mechanism for RPCGSS auth"
Cc: Simo Sorce <simo@redhat.com>
Reported-by: Olga Kornievskaia <kolga@netapp.com>
Tested-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/sunrpc/auth_gss/gss_rpc_xdr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sunrpc/auth_gss/gss_rpc_xdr.c
+++ b/net/sunrpc/auth_gss/gss_rpc_xdr.c
@@ -260,7 +260,7 @@ static int gssx_dec_option_array(struct
if (!oa->data)
return -ENOMEM;

- creds = kmalloc(sizeof(struct svc_cred), GFP_KERNEL);
+ creds = kzalloc(sizeof(struct svc_cred), GFP_KERNEL);
if (!creds) {
kfree(oa->data);
return -ENOMEM;