Re: [PATCH v2 2/6] sysctl: Fixes nsm_local_state bounds

Nicolas Bouchinet
2025-02-25T10:38:11Z

On 2/24/25 15:38, Chuck Lever wrote:
> On 2/24/25 4:58 AM, nicolas.bouchinet@clip-os.org wrote:
>> From: Nicolas Bouchinet <nicolas.bouchinet@ssi.gouv.fr>
>>
>> Bound nsm_local_state sysctl writings between SYSCTL_ZERO
>> and SYSCTL_INT_MAX.
>>
>> The proc_handler has thus been updated to proc_dointvec_minmax.
>>
>> Signed-off-by: Nicolas Bouchinet <nicolas.bouchinet@ssi.gouv.fr>
>> ---
>> fs/lockd/svc.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
>> index 2c8eedc6c2cc9..984ab233af8b6 100644
>> --- a/fs/lockd/svc.c
>> +++ b/fs/lockd/svc.c
>> @@ -461,7 +461,9 @@ static const struct ctl_table nlm_sysctls[] = {
>> .data = &nsm_local_state,
>> .maxlen = sizeof(int),
>> .mode = 0644,
>> - .proc_handler = proc_dointvec,
>> + .proc_handler = proc_dointvec_minmax,
>> + .extra1 = SYSCTL_ZERO,
>> + .extra2 = SYSCTL_INT_MAX,
>> },
>> };
>>
> Hi Nicolas -
>
> nsm_local_state is an unsigned 32-bit integer. The type of that value is
> defined by spec, because this value is exchanged between peers on the
> network.
>
> Perhaps this patch should replace proc_dointvec with proc_douintvec
> instead.
>
>

Hi Chuck,

Thank's for your review.

If `nsm_local_state` should be set to the
full range of an uint32_t by a user writing in the sysctl, then yes it
should
use `proc_douintvec` instead of limiting it to SYSCTL_INT_MAX value
(INT_MAX).

I've used `proc_dointvec_minmax` since it already used `proc_dointvec`
and thus
was already capped at INT_MAX.

Best regards,

Nicolas