[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2] fix potential pa_range_info out of bound access
On Mon, 12 Dec 2016, Julien Grall wrote: > Hi Stefano, > > On 09/12/16 19:46, Stefano Stabellini wrote: > > pa_range_info has only 8 elements and is accessed using pa_range as > > index. pa_range is initialized to 16, potentially causing out of bound > > access errors. Fix the issue by checking that pa_range is not greater > > than the size of the array. > > > > Coverity-ID: 1381865 > > > > Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx> > > > > diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c > > index e4991df..eb791db 100644 > > --- a/xen/arch/arm/p2m.c > > +++ b/xen/arch/arm/p2m.c > > @@ -1639,7 +1639,8 @@ void __init setup_virt_paging(void) > > } > > > > /* pa_range is 4 bits, but the defined encodings are only 3 bits */ > > - if ( pa_range&0x8 || !pa_range_info[pa_range].pabits ) > > + if ( pa_range >= ARRAY_SIZE(pa_range_info) || > > + pa_range&0x8 || !pa_range_info[pa_range].pabits ) > > I don't see any valid reason to check whether bit 3 is set (e.g the check > "pa_range&0x8"). IHMO it was a bad way to check if pa_range was in the array > index boundary. Given the comment, I think the author probably meant pa_range&0x7, but the new check is better. I'll remove it. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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