[PATCH v2] debug: Improve '%n' fortify detection (BZ 30932)

[Adhemerval Zanella Netto]

On 21/03/25 12:41, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>> The 7bb8045ec0 path made the '%n' fortify check ignore EMFILE errors
>> while trying to open /proc/self/maps, and this added a security
>> issue where EMFILE can be attacker-controlled thus making it
>> ineffective for some cases.
>>
>> The EMFILE failure is reinstated but with a different error
>> message.  Also, to improve the false positive of the hardening for
>> the cases where no new files can be opened, the
>> _dl_readonly_area now uses  _dl_find_object to check if the
>> memory area is within a writable ELF segment.  The procfs method is
>> still used as fallback.
>>
>> Checked on x86_64-linux-gnu and i686-linux-gnu.
>> --
>> Changes from v1:
>> * Rename readonly-area-arch to readonly-area-fallback.
>> * Handle found RW areas on _dl_readonly_area.
>> * Use l_relro_addr/l_relro_size in check_relro.
>> * Change variable names in tst-sprintf-fortify-rdonly-mod.c.
> 
> Adhemerval, are you looking for further comments on this patch?

No, I was focusing on the tst-origin breakage before install this.