wither bounds checking for networking sysctls

wither bounds checking for networking sysctls

[Rick Jones]

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

Re: wither bounds checking for networking sysctls

[Stephen Hemminger]

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.

Re: wither bounds checking for networking sysctls

[Rick Jones]

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.

rick jones

Re: wither bounds checking for networking sysctls

[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