Re: wither bounds checking for networking sysctls

[ebiederm@xmission.com (Eric W. Biederman)]

Rick Jones <rick.jones2@hp.com> writes:

> Stephen Hemminger wrote:
>> On Thu, 30 Aug 2007 18:09:17 -0700
>> Rick Jones <rick.jones2@hp.com> wrote:
>>
>>
>>> While messing about with "sysctl_tcp_rto_min" I went back and forth a bit as
>>> to whether there should have been bounds checking (as did some of the folks
>>> who did some internal review for me).  That leads to the question - is it
>>> considered worthwhile to add a bit more bounds checking to sundry networking
>>> sysctls?
>>>
>>>rick jones
>>
>>
>> IMHO As long as the any value from sysctl doesn't crash kernel, we
>> should let it go. Enforcing RFC policy or inter-dependencies seems
>> likes a useless exercise.
>
> I was thinking more along the lines of more fundamental things - like precluding
> negative values when something is clearly a positive.

The sysctl infrastructure has some fairly simple support for
doing min/max type things.  So if it makes sense it isn't hard to
make proc_dointvec_minmax the method and then set extra1 to point to
the min and extra2 to be the max. 

Eric