Hello,
I have found a possible out of bounds reading in
arch/powerpc/kvm/book3s_64_mmu.c (kvmppc_mmu_book3s_64_xlate
function). pteg[] array could be accessed twice using the i variable
after the for iteration. What happens is that in the last iteration
the i index is incremented to 16, checked (i<16) then confirmed
exiting the loop.
277 for (i=0; i<16; i+=2) { ...
Later there are reading attempts to the pteg last elements, but using
again the already incremented i (16).
303 v = be64_to_cpu(pteg[i]); /* pteg[16] */
304 r = be64_to_cpu(pteg[i+1]); /* pteg[17] */
I really don't know if the for lace will somehow iterate until i is
16, anyway I think that the last readings must be using a defined max
len/index or another more clear method.
Eg.
v = be64_to_cpu(pteg[PTEG_LEN - 2]);
r = be64_to_cpu(pteg[PTEG_LEN - 1]);
Or just.
v = be64_to_cpu(pteg[14]);
r = be64_to_cpu(pteg[15]);
----------------------------
I found in the same file a variable that is not used.
380 struct kvmppc_vcpu_book3s *vcpu_book3s;
...
387 vcpu_book3s = to_book3s(vcpu);
-----------------------------
A question, the kvmppc_mmu_book3s_64_init function is accessed by
unconventional way? Because I have not found any calling to it.
If something that I wrote is correct please tell me if I could send the patch.
--
Regards,
Geyslan G. Bem
hackingbits.com
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