Re: [PATCH 1/2] nfs4: fix discover_server_trunking use after free

Weston Andros Adamson
2014-01-21T15:04:21Z

On Jan 20, 2014, at 6:32 PM, Trond Myklebust <trond.myklebust@primarydata.com> wrote:

>
> On Jan 19, 2014, at 20:45, Weston Andros Adamson <dros@primarydata.com> wrote:
>
>> If clp is new (cl_count = 1) and it matches another client in
>> nfs4_discover_server_trunking, the nfs_put_client will free clp before
>> ->cl_preserve_clid is set.
>>
>> Cc: stable@vger.kernel.org # 3.7+
>> Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
>> ---
>> fs/nfs/nfs4client.c | 7 ++++---
>> 1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
>> index c1b7a80..0f9b772 100644
>> --- a/fs/nfs/nfs4client.c
>> +++ b/fs/nfs/nfs4client.c
>> @@ -414,11 +414,12 @@ struct nfs_client *nfs4_init_client(struct nfs_client *clp,
>> error = nfs4_discover_server_trunking(clp, &old);
>> if (error < 0)
>> goto error;
>> - nfs_put_client(clp);
>> - if (clp != old) {
>> +
>> + if (clp != old)
>> clp->cl_preserve_clid = true;
>> + nfs_put_client(clp);
>> + if (clp != old)
>> clp = old;
>> - }
>>
>
> Applied, but I cleaned it up by replacing the last 2 lines with an equivalent ‘return old’…

Cool, I almost posted that, but thought this change was a “cleaner” diff.

-dros

>
> --
> Trond Myklebust
> Linux NFS client maintainer
>
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