Re: [PATCH 3/4] security/selinux: decrement sizeof size in strncmp

[James Morris]

On Thu, 12 Nov 2009, Casey Schaufler wrote:

> I strongly suggest that this is not what is wanted.
>     strcmp(x,y)
> and
>     strncmp(x,y,sizeof(y))
> 
> are functionally equivalent and strcmp has a bad reputation in
> the security community because it is associated with potential
> buffer overrun issues.

Do you see potential for a buffer overrun in this case?

The strings being compared are "sysfs" and the name field of 'struct 
file_system_type'.  The kernel code elsewhere assumes the latter string to 
be a valid zero-terminated string, and we should, too.


- James
-- 
James Morris
<jmorris@xxxxxxxxx>
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