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| author |   Andrew Honig <ahonig@google.com> | 2018-01-10 10:12:03 -0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2018-01-11 18:20:31 +0100 |
| commit | 75f139aaf896d6fdeec2e468ddfa4b2fe469bf40 (patch) | |
| tree | e95c8451e33be341ccfaa853dd7a2927857882ef /arch/x86/kvm/vmx.c | |
| parent | Linux 4.14 (diff) | |
| download | linux-dev-75f139aaf896d6fdeec2e468ddfa4b2fe469bf40.tar.xz linux-dev-75f139aaf896d6fdeec2e468ddfa4b2fe469bf40.zip | |
KVM: x86: Add memory barrier on vmcs field lookup
This adds a memory barrier when performing a lookup into
the vmcs_field_to_offset_table. This is related to
CVE-2017-5753.
Signed-off-by: Andrew Honig <ahonig@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index a6f4f095f8f4..7f8fcc5ce664 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -884,8 +884,16 @@ static inline short vmcs_field_to_offset(unsigned long field) { BUILD_BUG_ON(ARRAY_SIZE(vmcs_field_to_offset_table) > SHRT_MAX); - if (field >= ARRAY_SIZE(vmcs_field_to_offset_table) || - vmcs_field_to_offset_table[field] == 0) + if (field >= ARRAY_SIZE(vmcs_field_to_offset_table)) + return -ENOENT; + + /* + * FIXME: Mitigation for CVE-2017-5753. To be replaced with a + * generic mechanism. + */ + asm("lfence"); + + if (vmcs_field_to_offset_table[field] == 0) return -ENOENT; return vmcs_field_to_offset_table[field]; |