Date: Tue, 30 Jun 2009 14:54:08 +0800 From: Eugene Teo <eugene@...hat.com> To: oss-security@...ts.openwall.com CC: "Steven M. Christey" <coley@...us.mitre.org> Subject: CVE Request: kernel: kvm: failure to validate cr3 after KVM_SET_SREGS "This applies to kvm-84 and earlier (and possibly to the in-kernel kvm version too) on all x86 machines in all guest modes (32-bit, PAE, 64-bit). Userspace callers of KVM_SET_SREGS can pass a bogus value of cr3 to the kernel. This will trigger a NULL pointer access in gfn_to_rmap() when userspace next tries to call KVM_RUN on the affected VCPU and kvm attempts to activate the new non-existent page table root. This happens since kvm only validates that cr3 points to a valid guest physical memory page when code *inside* the guest sets cr3. However, kvm currently trusts the userspace caller (e.g. QEMU) on the host machine to always supply a valid page table root, rather than properly validating it along with the rest of the reloaded guest state." Upstream patch: http://git.kernel.org/linus/59839dfff5eabca01cc4e20b45797a60a80af8cb References: http://sourceforge.net/tracker/?func=detail&atid=893831&aid=2687641&group_id=180599 http://git.kernel.org/?p=linux/kernel/git/stable/stable-queue.git;a=blob;f=queue-2.6.30/kvm-x86-check-for-cr3-validity-in-ioctl_set_sregs.patch;h=b48a47dad2cf76358b327368f80c0805e6370c68;hb=e7c45b24f298b5d9efd7d401150f64a1b51aaac4 Thanks, Eugene
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