Re: mpol_to_str revisited.

[Ben Hutchings]

On Mon, 2012-10-08 at 11:09 -0400, Dave Jones wrote:
> Last month I sent in 80de7c3138ee9fd86a98696fd2cf7ad89b995d0a to remove
> a user triggerable BUG in mempolicy.
> 
> Ben Hutchings pointed out to me that my change introduced a potential leak
> of stack contents to userspace, because none of the callers check the return value.
> 
> This patch adds the missing return checking, and also clears the buffer beforehand.
>
> Reported-by: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>

I was wearing my other hat at the time (ben@xxxxxxxxxxxxxxx).

> Cc: stable@xxxxxxxxxx
> Signed-off-by: Dave Jones <davej@xxxxxxxxxx>
> 
> --- 
> unanswered question: why are the buffer sizes here different ? which is correct?
[...]

Further question: why even use an intermediate buffer on the stack?
Both callers want to write the result to a seq_file.  Should mpol_str()
then be replaced with a seq_mpol()?

Ben.

-- 
Ben Hutchings
Who are all these weirdos? - David Bowie, about L-Space IRC channel #afp

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