diff options
| author | Tom Roeder <tmroeder@google.com> | 2019-01-25 00:48:20 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-01-25 20:53:10 +0300 |
| commit | 3a33d030daaa7c507e1c12d5adcf828248429593 (patch) | |
| tree | d9b8869868cac17b60e9db17605047669209d28d /arch | |
| parent | 85ba2b165d11029c0c57a58640d4cf41f9d9fa0d (diff) | |
| download | linux-3a33d030daaa7c507e1c12d5adcf828248429593.tar.xz | |
kvm: x86/vmx: Use kzalloc for cached_vmcs12
This changes the allocation of cached_vmcs12 to use kzalloc instead of
kmalloc. This removes the information leak found by Syzkaller (see
Reported-by) in this case and prevents similar leaks from happening
based on cached_vmcs12.
It also changes vmx_get_nested_state to copy out the full 4k VMCS12_SIZE
in copy_to_user rather than only the size of the struct.
Tested: rebuilt against head, booted, and ran the syszkaller repro
https://syzkaller.appspot.com/text?tag=ReproC&x=174efca3400000 without
observing any problems.
Reported-by: syzbot+ded1696f6b50b615b630@syzkaller.appspotmail.com
Fixes: 8fcc4b5923af5de58b80b53a069453b135693304
Cc: stable@vger.kernel.org
Signed-off-by: Tom Roeder <tmroeder@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/vmx/nested.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 2616bd2c7f2c..ce8153923854 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -4140,11 +4140,11 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu) if (r < 0) goto out_vmcs02; - vmx->nested.cached_vmcs12 = kmalloc(VMCS12_SIZE, GFP_KERNEL); + vmx->nested.cached_vmcs12 = kzalloc(VMCS12_SIZE, GFP_KERNEL); if (!vmx->nested.cached_vmcs12) goto out_cached_vmcs12; - vmx->nested.cached_shadow_vmcs12 = kmalloc(VMCS12_SIZE, GFP_KERNEL); + vmx->nested.cached_shadow_vmcs12 = kzalloc(VMCS12_SIZE, GFP_KERNEL); if (!vmx->nested.cached_shadow_vmcs12) goto out_cached_shadow_vmcs12; @@ -5263,13 +5263,17 @@ static int vmx_get_nested_state(struct kvm_vcpu *vcpu, copy_shadow_to_vmcs12(vmx); } - if (copy_to_user(user_kvm_nested_state->data, vmcs12, sizeof(*vmcs12))) + /* + * Copy over the full allocated size of vmcs12 rather than just the size + * of the struct. + */ + if (copy_to_user(user_kvm_nested_state->data, vmcs12, VMCS12_SIZE)) return -EFAULT; if (nested_cpu_has_shadow_vmcs(vmcs12) && vmcs12->vmcs_link_pointer != -1ull) { if (copy_to_user(user_kvm_nested_state->data + VMCS12_SIZE, - get_shadow_vmcs12(vcpu), sizeof(*vmcs12))) + get_shadow_vmcs12(vcpu), VMCS12_SIZE)) return -EFAULT; } |