Re: CVE request -- Linux kernel: call_console_drivers() Function Log Prefix Stripping buffer overflow

[Kurt Seifried <kseifried () redhat com>]

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On 02/26/2013 04:39 AM, Petr Matousek wrote:
> A buffer overflow flaw was found in kernels from 3.0 to 3.4 when
> calling log_prefix() function from call_console_drivers().
>
> This bug existed in previous releases but has been revealed with
> commit 162a7e7500f9664636e649ba59defe541b7c2c60 (2.6.39 => 3.0)
> that made changes about how to allocate memory for early printk
> buffer (use of memblock_alloc). It disappears with commit 
> 7ff9554bb578ba02166071d2d487b7fc7d860d62 (3.4 => 3.5) that does a 
> refactoring of printk buffer management.
>
> In log_prefix(), the access to "p[0]", "p[1]", "p[2]" or 
> "simple_strtoul(&p[1], &endp, 10)" may cause a buffer overflow as
> this function is called from call_console_drivers by passing 
> "&LOG_BUF(cur_index)" where the index must be masked to do not
> exceed the buffer's boundary.
>
> Note: /dev/kmsg is root writable only (at least on RHEL/Fedora),
> but it still might cause issues in restricted root environments.
>
> References: https://bugs.gentoo.org/458780 
> https://secunia.com/advisories/52366/
>
> Thanks,

Please use CVE-2013-1772 for this issue.

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993

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