[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Thu, 4 Feb 2010 15:46:02 -0700
From: dann frazier <dannf@...nf.org>
To: oss-security@...ts.openwall.com
Cc: "Steven M. Christey" <coley@...us.mitre.org>
Subject: Re: CVE request - kernel: DoS on x86_64
On Thu, Feb 04, 2010 at 01:09:09PM +0800, Eugene Teo wrote:
> On 02/04/2010 10:28 AM, dann frazier wrote:
>> On Mon, Feb 01, 2010 at 01:09:12PM +0800, Eugene Teo wrote:
>>> Reported by Mathias Krause. The problem seams to be located in
>>> fs/binfmt_elf.c:load_elf_binary(). It calls SET_PERSONALITY() prior
>>> checking that the ELF interpreter is available. This in turn makes the
>>> previously 32 bit process a 64 bit one which would be fine if execve()
>>> would succeed. But after the SET_PERSONALITY() the open_exec() call
>>> fails (because it cannot find the interpreter) and execve() almost
>>> instantly returns with an error. If you now look at /proc/PID/maps
>>> you'll see, that it has the vsyscall page mapped which shouldn't be. But
>>> the process is not dead yet, it's still running. By now generating a
>>> segmentation fault and in turn trying to generate a core dump the
>>> kernel just dies.
>>>
>>> Steps to Reproduce:
>>> 1. Enable core dumps
>>> 2. Start an 32 bit program that tries to execve() an 64 bit program
>>> 3. The 64 bit program cannot be started by the kernel because it can't
>>> find the interpreter, i.e. execve returns with an error
>>> 4. Generate a segmentation fault
>>> 5. panic
>>>
>>> Upstream commit:
>>> http://git.kernel.org/linus/221af7f87b97431e3ee21ce4b0e77d5411cf1549
>>
>> Thanks Eugene.
>>
>> Also note this fix for a regression in the above:
>> http://git.kernel.org/linus/7ab02af428c2d312c0cf8fb0b01cc1eb21131a3d
>
> Ben Hutchings reported (via stable review list) that the fix did not
> work for him. Will monitor the list if there are other follow-ups.
Indeed, it also needs this change for x86:
http://git.kernel.org/linus/05d43ed8a89c159ff641d472f970e3f1baa66318
And the corresponding changes for powerpc & sparc:
http://git.kernel.org/linus/94f28da8409c6059135e89ac64a0839993124155
http://git.kernel.org/linus/94673e968cbcce07fa78dac4b0ae05d24b5816e1
All are in queue-2.6.32 now, btw.
--
dann frazier
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
