Re: [PATCH v2] powerpc/mpc5xxx: Avoid dereferencing potentially freed memory

Gabriel Paubert
2015-10-16T07:15:52Z

On Fri, Oct 16, 2015 at 08:20:13AM +0200, Christophe JAILLET wrote:
> Le 15/10/2015 08:36, Michael Ellerman a écrit :
> >On Thu, 2015-10-15 at 07:56 +0200, Christophe JAILLET wrote:
> >>Use 'of_property_read_u32()' instead of 'of_get_property()'+pointer
> >>dereference in order to avoid access to potentially freed memory.
> >>
> >>Use 'of_get_next_parent()' to simplify the while() loop and avoid the
> >>need of a temp variable.
> >>
> >>Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> >>---
> >>v2: Use of_property_read_u32 instead of of_get_property+pointer dereference
> >>*** Untested ***
> >Thanks.
> >
> >Can someone with an mpc5xxx test this?
> >
> >cheers
> >
>
> Hi,
> I don't think it is an issue, but while looking at another similar
> patch, I noticed that the proposed patch adds a call to
> be32_to_cpup() (within of_property_read_u32).
> Apparently, powerPC is a BE architecture, so this call should be a no-op.

Sadly no more. 32 bit is BE only, but 64 bit can be either BEtter or
LEsser.

Gabriel
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