Messages in this thread |  | | From | Michael Buesch <> | Subject | Re: [PATCH] nvram: Fix root triggerable integer overflow crash | Date | Sat, 18 Jul 2009 19:44:33 +0200 |
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On Saturday 18 July 2009 17:09:09 Henrique de Moraes Holschuh wrote: > On Sat, 18 Jul 2009, Michael Buesch wrote: > > This bug probably is exploitable by overwriting the function return address or something > > like that. But let's hope there's no distribution out there with user write permissions > > on the /dev/nvram node. So it's probably only exploitable by root. > > I have seen setups with group-writeable /dev/nvram to support some (old!) > thinkpad utilities.
Yes it is crw-rw---- 1 root root on Debian. Are there any setuid programs accessing nvram (like the recent tun/pulseaudio exploit?)
> Even if it cannot be exploited for more than a DoS,
You can randomly overwrite the kernel stack with the data you write to the device. So I do think it is exploitable, because the char device writer controls the kernel stack completely. However, I do not have an example exploit.
> IMO that's still bad > enough to warrant fixing this also on stable kernels if they are vulnerable. > So, does the fix also apply to 2.6.27+ ? If it does, please send it to > stable@kernel.org as well.
Yeah I forgot to add stable to CC.
-- Greetings, Michael.
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