Re: [RFC] _FORTIFY_SOURCE strictness

[Siddhesh Poyarekar <siddhesh@gotplt.org>]

On 08/04/2022 11:07, Florian Weimer wrote:
> * Siddhesh Poyarekar:
> 
>> This is not limited to the two known examples either; __strncpy_chk
>> for example will crash if n is greater than the destination buffer
>> size and is similarly prone to such false positives.  One could
>> envision a situation where an strncpy call is deeply nested and
>> through compiler advances and attribute annotations, the callsite now
>> gets precise size expressions for the call and not just an upper limit
>> estimate or a (size_t)-1.
> 
> Hmm.  __strncpy_chk always fills the destination buffer, so the only
> thing we can do here is to alias it to strncpy?

Hmm, I think I conflated it with something other str* function.  You're 
right, strncpy probably doesn't fall into this category.

Thanks,
Siddhesh