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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: 045a282ca4
("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>
This commit is contained in:
parent
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commit
3c9053a2ca
1 changed files with 8 additions and 3 deletions
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@ -5288,10 +5288,15 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
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}
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break;
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case Escape:
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if (ctxt->modrm > 0xbf)
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opcode = opcode.u.esc->high[ctxt->modrm - 0xc0];
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else
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if (ctxt->modrm > 0xbf) {
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size_t size = ARRAY_SIZE(opcode.u.esc->high);
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u32 index = array_index_nospec(
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ctxt->modrm - 0xc0, size);
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opcode = opcode.u.esc->high[index];
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} else {
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opcode = opcode.u.esc->op[(ctxt->modrm >> 3) & 7];
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}
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break;
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case InstrDual:
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if ((ctxt->modrm >> 6) == 3)
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