Is this really a CVE? - buffer overflow in handling of MSR_KVM_SYSTEM_TIME (CVE-2013-1796)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The CVE-2013-1796
(https://git.kernel.org/cgit/virt/kvm/kvm.git/commit/?id=c300aa64ddf57d9c5d9c898a64b36877345dd4a9)
reports a possibility of host memory corruption.
I see that this could lead into corruption of guest kernel memory,
but how could be the wrong aligned address reported by guest corrupt
host kernel memory?


Regards, Florian

------------------
This was the posted fix for CVE-2013-1796:
------------------
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f7c850b..2ade60c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1959,6 +1959,11 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu,
struct msr_data *msr_info)
/* ...but clean it before doing the actual write */
vcpu->arch.time_offset = data & ~(PAGE_MASK | 1);
+ /* Check that the address is 32-byte aligned. */
+ if (vcpu->arch.time_offset &
+ (sizeof(struct pvclock_vcpu_time_info) - 1))
+ break;
+
vcpu->arch.time_page =
gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT);
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux