This is a note to let you know that I've just added the patch titled
KVM: x86: Fix uninitialized op->type for some immediate values
to the 3.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-fix-uninitialized-op-type-for-some-immediate-values.patch
and it can be found in the queue-3.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d29b9d7ed76c0b961603ca692b8a562556a20212 Mon Sep 17 00:00:00 2001
From: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
Date: Sun, 2 Nov 2014 11:54:47 +0200
Subject: KVM: x86: Fix uninitialized op->type for some immediate values
From: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4272,6 +4272,7 @@ static int decode_operand(struct x86_emu
fetch_register_operand(op);
break;
case OpCL:
+ op->type = OP_IMM;
op->bytes = 1;
op->val = reg_read(ctxt, VCPU_REGS_RCX) & 0xff;
break;
@@ -4279,6 +4280,7 @@ static int decode_operand(struct x86_emu
rc = decode_imm(ctxt, op, 1, true);
break;
case OpOne:
+ op->type = OP_IMM;
op->bytes = 1;
op->val = 1;
break;
@@ -4337,21 +4339,27 @@ static int decode_operand(struct x86_emu
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:
Patches currently in stable-queue which might be from namit@xxxxxxxxxxxxxxxxx are
queue-3.17/kvm-x86-fix-uninitialized-op-type-for-some-immediate-values.patch
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