Date: Mon, 21 Jul 2014 14:17:47 +0200 From: Florian Weimer <fweimer@...hat.com> To: oss-security@...ts.openwall.com Subject: Re: Re: glibc locale issues On 07/14/2014 04:15 AM, Tavis Ormandy wrote: > Tavis Ormandy <taviso@...xchg8b.com> wrote: > >> I just remembered another charset issues I had looked into but abandoned. >> >> First of all, I think the need_so logic in gconv_trans is broken, but even >> if it worked there is an off by one error in __gconv_translit_find() (it >> does + 3 instead of + 3 + 1 in the allocation. > > To be clear, I suspect this is exploitable. It would be nice if you could > modify the buffer such that gconv will open a path with a string you've > appended it (e.g. CHARSET=//. pkexec ./../../../../tmp/foo.so), This is about the glib part and the alias processing, right? iconv/gconv_charset.h:strip() normalizes the transliteration argument to iconv_open, so the resulting file names follow a particular pattern, and there cannot be enough slashes to ascend to a writable directory. > if not maybe the one byte overflow is still exploitable. Hmm. How likely is that? It overflows in to malloc metadata, and the glibc malloc hardening should catch that these days. -- Florian Weimer / Red Hat Product Security
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