Messages in this thread Patch in this message | | | From | lizf@kernel ... | Subject | [PATCH 3.4 152/177] KVM: x86: Fix uninitialized op->type for some immediate values | Date | Wed, 28 Jan 2015 12:10:10 +0800 |
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From: Nadav Amit <namit@cs.technion.ac.il>
3.4.106-rc1 review patch. If anyone has any objections, please let me know.
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commit d29b9d7ed76c0b961603ca692b8a562556a20212 upstream.
The emulator could reuse an op->type from a previous instruction for some immediate values. If it mistakenly considers the operands as memory operands, it will performs a memory read and overwrite op->val.
Consider for instance the ROR instruction - src2 (the number of times) would be read from memory instead of being used as immediate.
Mark every immediate operand as such to avoid this problem.
Fixes: c44b4c6ab80eef3a9c52c7b3f0c632942e6489aa Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Zefan Li <lizefan@huawei.com> --- arch/x86/kvm/emulate.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index e125c3e..0a12507 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3833,6 +3833,7 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, fetch_register_operand(op); break; case OpCL: + op->type = OP_IMM; op->bytes = 1; op->val = ctxt->regs[VCPU_REGS_RCX] & 0xff; break; @@ -3840,6 +3841,7 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, rc = decode_imm(ctxt, op, 1, true); break; case OpOne: + op->type = OP_IMM; op->bytes = 1; op->val = 1; break; @@ -3879,21 +3881,27 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, ctxt->memop.bytes = ctxt->op_bytes + 2; goto mem_common; case OpES: + op->type = OP_IMM; op->val = VCPU_SREG_ES; break; case OpCS: + op->type = OP_IMM; op->val = VCPU_SREG_CS; break; case OpSS: + op->type = OP_IMM; op->val = VCPU_SREG_SS; break; case OpDS: + op->type = OP_IMM; op->val = VCPU_SREG_DS; break; case OpFS: + op->type = OP_IMM; op->val = VCPU_SREG_FS; break; case OpGS: + op->type = OP_IMM; op->val = VCPU_SREG_GS; break; case OpImplicit: -- 1.9.1
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