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SubjectRe: [PATCH v5 2/9] proc/sysctl: Provide additional ctl_table.flags checks
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On 03/16/2018 08:54 PM, Luis R. Rodriguez wrote:
> On Fri, Mar 16, 2018 at 02:13:43PM -0400, Waiman Long wrote:
>> Checking code is added to provide the following additional
>> ctl_table.flags checks:
>>
>> 1) No unknown flag is allowed.
>> 2) Minimum of a range cannot be larger than the maximum value.
>> 3) The signed and unsigned flags are mutually exclusive.
>> 4) The proc_handler should be consistent with the signed or unsigned
>> flags.
>>
>> Two new flags are added to indicate if the min/max values are signed
>> or unsigned - CTL_FLAGS_SIGNED_RANGE & CTL_FLAGS_UNSIGNED_RANGE.
>> These 2 flags can be optionally enabled for range checking purpose.
>> But either one of them must be set with CTL_FLAGS_CLAMP_RANGE.
>>
>> Signed-off-by: Waiman Long <longman@redhat.com>
>> ---
>> diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
>> index e446e1f..088f032 100644
>> --- a/include/linux/sysctl.h
>> +++ b/include/linux/sysctl.h
>> @@ -134,14 +134,26 @@ struct ctl_table
>> * the input value. No lower bound or upper bound checking will be
>> * done if the corresponding minimum or maximum value isn't provided.
>> *
>> + * @CTL_FLAGS_SIGNED_RANGE: Set to indicate that the extra1 and extra2
>> + * fields are pointers to minimum and maximum signed values of
>> + * an allowable range.
>> + *
>> + * @CTL_FLAGS_UNSIGNED_RANGE: Set to indicate that the extra1 and extra2
>> + * fields are pointers to minimum and maximum unsigned values of
>> + * an allowable range.
>> + *
>> * At most 16 different flags are allowed.
>> */
>> enum ctl_table_flags {
>> CTL_FLAGS_CLAMP_RANGE = BIT(0),
>> - __CTL_FLAGS_MAX = BIT(1),
>> + CTL_FLAGS_SIGNED_RANGE = BIT(1),
>> + CTL_FLAGS_UNSIGNED_RANGE = BIT(2),
>> + __CTL_FLAGS_MAX = BIT(3),
>> };
> You are adding new flags which the user can set, and yet these are used
> internally.
>
> It would be best if internal flags are just that, not flags that a user can set.
>
> This patch should be folded with the first one.
>
> I'm starting to loose hope on these patch sets.
>
> Luis

In order to do the correct min > max check, I need to know if the
quantity is signed or not. Just looking at the proc_handler alone is not
a reliable indicator if it is signed or unsigned.

Yes, I can put the signed bit into the previous patch.

-Longman


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