> On Sep 22, 2021, at 11:45 AM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>
> On Thu, Sep 16, 2021 at 03:03:32PM -0400, Chuck Lever wrote:
>> Dai Ngo reports that, since the XDR overhaul, the NLM server crashes
>> when the TEST procedure wants to return NLM_DENIED. There is a bug
>> in svcxdr_encode_owner() that none of our standard test cases found.
>>
>> Replace the open-coded function with a call to an appropriate
>> pre-fabricated XDR helper.
>
> Makes sense to me. I assume you're taking this for 5.15.--b.
Yes. I'm just finishing up testing for the next -rc PR.
>> Reported-by: Dai Ngo <Dai.Ngo@xxxxxxxxxx>
>> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
>> ---
>> fs/lockd/svcxdr.h | 13 ++-----------
>> 1 file changed, 2 insertions(+), 11 deletions(-)
>>
>> This might be a little better for the long term. Comments?
>>
>> diff --git a/fs/lockd/svcxdr.h b/fs/lockd/svcxdr.h
>> index c69a0bb76c94..805fb19144d7 100644
>> --- a/fs/lockd/svcxdr.h
>> +++ b/fs/lockd/svcxdr.h
>> @@ -134,18 +134,9 @@ svcxdr_decode_owner(struct xdr_stream *xdr, struct xdr_netobj *obj)
>> static inline bool
>> svcxdr_encode_owner(struct xdr_stream *xdr, const struct xdr_netobj *obj)
>> {
>> - unsigned int quadlen = XDR_QUADLEN(obj->len);
>> - __be32 *p;
>> -
>> - if (xdr_stream_encode_u32(xdr, obj->len) < 0)
>> - return false;
>> - p = xdr_reserve_space(xdr, obj->len);
>> - if (!p)
>> + if (unlikely(obj->len > XDR_MAX_NETOBJ))
>> return false;
>> - p[quadlen - 1] = 0; /* XDR pad */
>> - memcpy(p, obj->data, obj->len);
>> -
>> - return true;
>> + return xdr_stream_encode_opaque(xdr, obj->data, obj->len) > 0;
>> }
>>
>> #endif /* _LOCKD_SVCXDR_H_ */
>>
--
Chuck Lever
