netdev - Re: [SECURITY] CAN info leak/minor heap overflow

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Message-ID: <4CD071B6.7030202@hartkopp.net>
Date:	Tue, 02 Nov 2010 21:16:54 +0100
From:	Oliver Hartkopp <socketcan@...tkopp.net>
To:	Dan Rosenberg <drosenberg@...curity.com>
CC:	netdev@...r.kernel.org, security@...nel.org
Subject: Re: [SECURITY] CAN info leak/minor heap overflow

On 02.11.2010 20:53, Dan Rosenberg wrote:
> 
>> Why is this bad? Can the addresses of CAN-BCM sock structs be used for
>> anything from userspace?
>>
>> For me they are just intended to be unique numbers ...
>>
> 
> This is a bad idea because it makes exploiting other kernel
> vulnerabilities easier.  Exposing the address of an object in a slab
> cache, especially an object that unprivileged users have some level of
> control of, is just an invitation to use that structure when writing
> exploits, for heap overflows or otherwise.

The "level of control of" is just creating a socket or not. None of the data
in the created struct can be influenced by an unprivileged user.
Btw. i can generally follow your concerns after this explanation.

I'm going to check the kernel src for other approaches to display unique
numbers in procfs and will send a patch that takes care.

Thanks,
Oliver
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