Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934200AbaKSWYa (ORCPT ); Wed, 19 Nov 2014 17:24:30 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:56108 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932472AbaKSUyI (ORCPT ); Wed, 19 Nov 2014 15:54:08 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nadav Amit , Paolo Bonzini Subject: [PATCH 3.17 041/141] KVM: x86: Fix uninitialized op->type for some immediate values Date: Wed, 19 Nov 2014 12:51:04 -0800 Message-Id: <20141119205152.016110326@linuxfoundation.org> X-Mailer: git-send-email 2.1.3 In-Reply-To: <20141119205150.700188369@linuxfoundation.org> References: <20141119205150.700188369@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nadav Amit 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 Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- 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: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/