diff options
| author | Marios Pomonis <pomonis@google.com> | 2019-12-11 23:47:41 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-01-27 21:59:35 +0300 |
| commit | 3c9053a2cae7ba2ba73766a34cea41baa70f57f7 (patch) | |
| tree | f467c18a592af256a1117083298575c9992720e6 /arch/x86/kvm | |
| parent | a47970ed74a535b1accb4bc73643fd5a93993c3e (diff) | |
| download | linux-3c9053a2cae7ba2ba73766a34cea41baa70f57f7.tar.xz | |
KVM: x86: Protect x86_decode_insn from Spectre-v1/L1TF attacks
This fixes a Spectre-v1/L1TF vulnerability in x86_decode_insn().
kvm_emulate_instruction() (an ancestor of x86_decode_insn()) is an exported
symbol, so KVM should treat it conservatively from a security perspective.
Fixes: 045a282ca415 ("KVM: emulator: implement fninit, fnstsw, fnstcw")
Signed-off-by: Nick Finco <nifi@google.com>
Signed-off-by: Marios Pomonis <pomonis@google.com>
Reviewed-by: Andrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index e9833e345a5c..2d4faefe8dd4 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5288,10 +5288,15 @@ done_prefixes: } break; case Escape: - if (ctxt->modrm > 0xbf) - opcode = opcode.u.esc->high[ctxt->modrm - 0xc0]; - else + if (ctxt->modrm > 0xbf) { + size_t size = ARRAY_SIZE(opcode.u.esc->high); + u32 index = array_index_nospec( + ctxt->modrm - 0xc0, size); + + opcode = opcode.u.esc->high[index]; + } else { opcode = opcode.u.esc->op[(ctxt->modrm >> 3) & 7]; + } break; case InstrDual: if ((ctxt->modrm >> 6) == 3) |