From: Waiman Long <longman@redhat.com>
To: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH v2 2/5] sysctl: Add flags to support min/max range clamping
Date: Thu, 1 Mar 2018 12:40:04 -0500 [thread overview]
Message-ID: <5d13fde9-2b9e-69e8-c263-9fd9d093e293@redhat.com> (raw)
In-Reply-To: <e5ac80d5-2919-8944-293d-ee9b70f6ad02@redhat.com>
On 02/28/2018 01:58 PM, Waiman Long wrote:
> On 02/28/2018 01:43 PM, Luis R. Rodriguez wrote:
>> On Wed, Feb 28, 2018 at 12:53:40PM -0500, Waiman Long wrote:
>>> On 02/27/2018 07:47 PM, Luis R. Rodriguez wrote:
>>>> On Tue, Feb 27, 2018 at 03:49:48PM -0500, Waiman Long wrote:
>>>>> When minimum/maximum values are specified for a sysctl parameter in
>>>>> the ctl_table structure with proc_dointvec_minmax() handler,
>>>> an
>>>>
>>>>> update
>>>>> to that parameter will fail with error if the given value is outside
>>>>> of the required range.
>>>>>
>>>>> There are use cases where it may be better to clamp the value of
>>>>> the sysctl parameter to the given range without failing the update,
>>>>> especially if the users are not aware of the actual range limits.
>>>> Makes me wonder if we should add something which does let one query
>>>> for the ranges. Then scripts can fetch that as well.
>>> That will actually be better than printing out the range in the dmesg
>>> log. However, I haven't figured out an easy way of doing that. If you
>>> have any suggestion, please let me know about it.
>> I think a macro that also adds yet another proc read-only entry with a postfix
>> "_range" with an internal handler which prints the range may suffice.
>>
>> Luis
> I think that is a possible solution. Instead of adding a macro, I will
> add one more flag which does the magic when the ctl_table entry is being
> processed. I think that will be simpler from the user point of view.
>
> Cheers,
> Longman
>
This patch will take a bit more time to work on. So I am going to do it
as a separate patch on top of the current one later. I don't want to
delay the review of the current patch set.
Cheers,
Longman
next prev parent reply other threads:[~2018-03-01 17:40 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-27 20:49 [PATCH v2 0/5] ipc: Clamp *mni to the real IPCMNI limit Waiman Long
2018-02-27 20:49 ` [PATCH v2 1/5] sysctl: Add kdoc comments to do_proc_do{u}intvec_minmax_conv_param Waiman Long
2018-02-27 21:10 ` Matthew Wilcox
2018-02-27 21:52 ` Waiman Long
2018-02-27 20:49 ` [PATCH v2 2/5] sysctl: Add flags to support min/max range clamping Waiman Long
2018-02-28 0:47 ` Luis R. Rodriguez
2018-02-28 17:53 ` Waiman Long
2018-02-28 18:43 ` Luis R. Rodriguez
2018-02-28 18:58 ` Waiman Long
2018-02-28 19:06 ` Luis R. Rodriguez
2018-03-01 17:40 ` Waiman Long [this message]
2018-02-27 20:49 ` [PATCH v2 3/5] sysctl: Warn when a clamped sysctl parameter is set out of range Waiman Long
2018-02-28 0:57 ` Luis R. Rodriguez
2018-02-28 17:55 ` Waiman Long
2018-02-27 20:49 ` [PATCH v2 4/5] ipc: Clamp msgmni and shmmni to the real IPCMNI limit Waiman Long
2018-02-28 1:01 ` Luis R. Rodriguez
2018-02-28 17:56 ` Waiman Long
2018-02-27 20:49 ` [PATCH v2 5/5] ipc: Clamp semmni " Waiman Long
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