| Message ID | 1365671381-12762-1-git-send-email-luis.henriques@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8b6fbee..ad5cf4b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1618,6 +1618,11 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) /* ...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);
This is a note to let you know that I have just added a patch titled KVM: x86: fix for buffer overflow in handling of to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 9ebdfca37460b564bc58ca0a50a477fba06250e0 Mon Sep 17 00:00:00 2001 From: Andy Honig <ahonig@google.com> Date: Mon, 11 Mar 2013 09:34:52 -0700 Subject: [PATCH] KVM: x86: fix for buffer overflow in handling of MSR_KVM_SYSTEM_TIME (CVE-2013-1796) commit c300aa64ddf57d9c5d9c898a64b36877345dd4a9 upstream. If the guest sets the GPA of the time_page so that the request to update the time straddles a page then KVM will write onto an incorrect page. The write is done byusing kmap atomic to get a pointer to the page for the time structure and then performing a memcpy to that page starting at an offset that the guest controls. Well behaved guests always provide a 32-byte aligned address, however a malicious guest could use this to corrupt host kernel memory. Tested: Tested against kvmclock unit test. Signed-off-by: Andrew Honig <ahonig@google.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- arch/x86/kvm/x86.c | 5 +++++ 1 file changed, 5 insertions(+) -- 1.8.1.2