Re: [ 043/218] ARM: 7527/1: uaccess: explicitly check __userpointer when !CPU_USE_DOMAINS

[Ben Hutchings]

On Fri, 2012-09-28 at 13:14 -0700, Greg Kroah-Hartman wrote:
> 3.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
> 
> commit 8404663f81d212918ff85f493649a7991209fa04 upstream.
> 
> The {get,put}_user macros don't perform range checking on the provided
> __user address when !CPU_HAS_DOMAINS.
> 
> This patch reworks the out-of-line assembly accessors to check the user
> address against a specified limit, returning -EFAULT if is is out of
> range.
> 
> [will: changed get_user register allocation to match put_user]
> [rmk: fixed building on older ARM architectures]
[...]

It looks like this is needed for at least some older kernel versions,
but a backported version will be needed for 3.2 and earlier.

Ben.

-- 
Ben Hutchings
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