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Subject: Re: [PATCH 3.10 112/250] svcrpc: fix oops in absence of krb5 module
From: Simo Sorce <simo@redhat.com>
To: Willy Tarreau <w@1wt.eu>, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, linux@roeck-us.net
Cc: "J. Bruce Fields" <bfields@redhat.com>
Date: Thu, 08 Jun 2017 04:19:37 -0400
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On Thu, 2017-06-08 at 00:58 +0200, Willy Tarreau wrote:
> 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.

Nice catch!
Ack.

Simo.

> [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: Willy Tarreau <w@1wt.eu>
> ---
>  net/sunrpc/auth_gss/gss_rpc_xdr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/sunrpc/auth_gss/gss_rpc_xdr.c
> b/net/sunrpc/auth_gss/gss_rpc_xdr.c
> index e0062c5..a9ca705 100644
> --- 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
> xdr_stream *xdr,
>  	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;