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Re: Fwd: [PATCH] Don't allow attackers to inject arbitrary data into stack through LD_DEBUG
- From: Andreas Schwab <schwab at suse dot de>
- To: Alex <alexinbeijing at gmail dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Mon, 10 Aug 2015 10:49:56 +0200
- Subject: Re: Fwd: [PATCH] Don't allow attackers to inject arbitrary data into stack through LD_DEBUG
- Authentication-results: sourceware.org; auth=none
- References: <1439153945-22973-1-git-send-email-alexinbeijing at gmail dot com> <87fv3s83td dot fsf at igel dot home> <CACsECNf6dB8cAG4EHpox=tg8=+SbeWTb9J=T4zArLtmdQjqkHQ at mail dot gmail dot com> <CACsECNeWcACbJ50wYcrWL804G9o7T8eZT57oFZWS17jVZ98SxA at mail dot gmail dot com>
Alex <alexinbeijing@gmail.com> writes:
> On Mon, Aug 10, 2015 at 1:01 AM, Andreas Schwab <schwab@linux-m68k.org> wrote:
>> Alex Dowad <alexinbeijing@gmail.com> writes:
>>
>>> diff --git a/elf/rtld.c b/elf/rtld.c
>>> index 6dcbabc..ee194a6 100644
>>> --- a/elf/rtld.c
>>> +++ b/elf/rtld.c
>>> @@ -2408,6 +2408,8 @@ process_dl_debug (const char *dl_debug)
>>> char *copy = strndupa (dl_debug, len);
>>> _dl_error_printf ("\
>>> warning: debug option `%s' unknown; try LD_DEBUG=help\n", copy);
>>
>> Use %.*s instead.
>
> Thanks for your reply. That would help to avoid potentially voluminous
> output to the console, but doesn't fix the (potential) security hole
> of copying an arbitrary, attacker-supplied string onto the stack.
You don't need the copy any more.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
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