Re: [libmicrohttpd] GNU libmicrohttpd 0.9.74 released

[Markus Doppelbauer]

Dear Evgeny,

All problems are gone.

Thank you for all your efforts.

Best wishes

Markus

-------- Ursprüngliche Nachricht --------

Von: Evgeny Grin <k2k@yandex.ru>

Antwort an: libmicrohttpd development and user mailinglist <libmicrohttpd@gnu.org>

An: libmicrohttpd@gnu.org

Betreff: Re: [libmicrohttpd] GNU libmicrohttpd 0.9.74 released

Datum: Mon, 7 Mar 2022 21:56:43 +0300

Hi Markus,

Thanks for the report.

Unfortunatelly ASAN documentation is not very precise about manual 

poisoning/unpoisoning, however I think memory must be *unpoisoned* 

before freeing, just because memory is not poisoned when allocated.

Should be fixed by 

https://git.gnunet.org/libmicrohttpd.git/commit/?id=1a46bfd6e0929e2004ffda318282cbf21d9f5299

Please check whether it fixed the issue for you.

-- 

Evgeny

On 07.03.2022 20:11, Markus Doppelbauer wrote:

 > + Added '--enable-sanitizers[=address,undefined,leak,user-poison]'

 >    configure parameter (instead of '--enable-sanitizer'),

 >    implemented custom memory poisoning for memory pools.

We get strange asan aborts (maybe once per 30min):

    ERROR: AddressSanitizer: use-after-poison on address 0xdeadbeef

My question (sorry I can't find any docs on this issue):

MHD calls '_MHD_POISON_MEMORY()' before 'free()'.

Other code calls 'ASAN_UNPOISON_MEMORY_REGION()' before free, e.g.:

https://github.com/AlxHnr/CRegion/blob/1347314d953e8b5e26eed3b0fe3151e482958c39/src/mempool.c#L69

<

https://github.com/AlxHnr/CRegion/blob/1347314d953e8b5e26eed3b0fe3151e482958c39/src/mempool.c#L69

>