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>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v4 2/6] proc/sysctl: Check for invalid flags bits
Date: Mon, 12 Mar 2018 17:02:55 -0400 [thread overview]
Message-ID: <fdb198a7-8986-3a85-f8ca-9952866a966e@redhat.com> (raw)
In-Reply-To: <20180312205920.GD4449@wotan.suse.de>
On 03/12/2018 04:59 PM, Luis R. Rodriguez wrote:
> On Mon, Mar 12, 2018 at 04:54:51PM -0400, Waiman Long wrote:
>> On 03/12/2018 04:46 PM, Luis R. Rodriguez wrote:
>>> On Mon, Mar 12, 2018 at 04:15:40PM -0400, Waiman Long wrote:
>>>> Checking code is added to check for invalid flags in the ctl_table
>>>> and return error if an unknown flag is used.
>>> This should be merged with the first patch otherwise there are atomic
>>> points in time on the commit log history where invalid values are allowed
>>> and that makes no sense.
>>>
>>> This can probably be expanded to verify semantics further. Details
>>> below.
>>>> Signed-off-by: Waiman Long <longman@redhat.com>
>>>> ---
>>>> fs/proc/proc_sysctl.c | 12 ++++++++++++
>>>> 1 file changed, 12 insertions(+)
>>>>
>>>> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
>>>> index 493c975..67c0c82 100644
>>>> --- a/fs/proc/proc_sysctl.c
>>>> +++ b/fs/proc/proc_sysctl.c
>>>> @@ -1092,6 +1092,16 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table)
>>>> return err;
>>>> }
>>>>
>>>> +static int sysctl_check_flags(const char *path, struct ctl_table *table)
>>>> +{
>>>> + int err = 0;
>>>> +
>>>> + if (table->flags & ~CTL_TABLE_FLAGS_ALL)
>>>> + err = sysctl_err(path, table, "invalid flags");
>>> What if a range for the upper limit is set but not the lower limit and
>>> the user goes over the lower limit?
>>>
>>> How about the inverse?
>>>
>>> Do we need both ranges set?
>>>
>>> Luis
>> This check is just to make sure that no invalid flag bit is set. Range
>> clamping is just one of flag bits, though this is the only one currently
>> supported. In fact, it is allowed that the minimum or maximum can be
>> left unspecified. In this case, no minimum or maximum checking will be
>> done. So I don't see anything related to range checking should be put here.
> What if minimum is greater than maximum?
>
> Luis
Yes, you are right. That is a valid check. I am going to add that in the
next patch.
Cheers,
Longman
next prev parent reply other threads:[~2018-03-12 21:02 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-12 20:15 [PATCH v4 0/6] ipc: Clamp *mni to the real IPCMNI limit Waiman Long
2018-03-12 20:15 ` [PATCH v4 1/6] sysctl: Add flags to support min/max range clamping Waiman Long
2018-03-12 20:44 ` Luis R. Rodriguez
2018-03-12 20:48 ` Waiman Long
2018-03-13 17:46 ` Eric W. Biederman
2018-03-13 18:49 ` Waiman Long
2018-03-12 20:15 ` [PATCH v4 2/6] proc/sysctl: Check for invalid flags bits Waiman Long
2018-03-12 20:46 ` Luis R. Rodriguez
2018-03-12 20:54 ` Waiman Long
2018-03-12 20:59 ` Luis R. Rodriguez
2018-03-12 21:02 ` Waiman Long [this message]
2018-03-12 20:52 ` Andrew Morton
2018-03-12 22:12 ` Waiman Long
2018-03-12 22:42 ` Andrew Morton
2018-03-12 20:15 ` [PATCH v4 3/6] sysctl: Warn when a clamped sysctl parameter is set out of range Waiman Long
2018-03-12 20:50 ` Luis R. Rodriguez
2018-03-12 21:07 ` Waiman Long
2018-03-12 21:00 ` Andrew Morton
2018-03-12 21:04 ` Waiman Long
2018-03-12 20:15 ` [PATCH v4 4/6] ipc: Clamp msgmni and shmmni to the real IPCMNI limit Waiman Long
2018-03-13 18:17 ` Eric W. Biederman
2018-03-13 18:39 ` Waiman Long
2018-03-13 20:29 ` Eric W. Biederman
2018-03-13 21:06 ` Waiman Long
2018-03-15 0:49 ` [RFC][PATCH] ipc: Remove IPCMNI Eric W. Biederman
2018-03-15 17:02 ` Waiman Long
2018-03-15 19:00 ` Eric W. Biederman
2018-03-15 21:46 ` Waiman Long
2018-03-29 2:14 ` Davidlohr Bueso
2018-03-29 8:47 ` Manfred Spraul
2018-03-29 10:56 ` Matthew Wilcox
2018-03-29 18:07 ` Manfred Spraul
2018-03-29 18:52 ` Eric W. Biederman
2018-03-29 19:32 ` Matthew Wilcox
2018-03-29 20:08 ` Eric W. Biederman
2018-03-15 19:45 ` Matthew Wilcox
2018-03-12 20:15 ` [PATCH v4 5/6] ipc: Clamp semmni to the real IPCMNI limit Waiman Long
2018-03-12 20:52 ` Luis R. Rodriguez
2018-03-12 20:59 ` Waiman Long
2018-03-12 20:15 ` [PATCH v4 6/6] test_sysctl: Add range clamping test Waiman Long
2018-03-12 20:53 ` Luis R. Rodriguez
2018-03-12 21:00 ` Waiman Long
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