From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CED4EC433EF for ; Tue, 12 Jul 2022 18:41:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233788AbiGLSlb (ORCPT ); Tue, 12 Jul 2022 14:41:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230289AbiGLSlC (ORCPT ); Tue, 12 Jul 2022 14:41:02 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 55277D516D; Tue, 12 Jul 2022 11:40:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A7B0CB81BAC; Tue, 12 Jul 2022 18:40:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03545C3411C; Tue, 12 Jul 2022 18:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657651245; bh=BG/lLgX4NwTF3EnPyMMuoXxPZhMhojq+mHhCZtZ5XxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wxFvlgyuG5ZT2zfa1q9/JSRhIQNw/cbXC9Vx7kP6YyFYmp3qc9jiCVTiyKiyWMJeC cG7BvVlYCyYkFB3A4SYWOqkrWdDOLp1hXmTGHFfOUt2qTFe4sMg61IEjHy1xp3xf/v 9LThRrG1GSG2OjovBWJAIkzrvwmKoe1q6QDh5qf8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Borislav Petkov , Ben Hutchings Subject: [PATCH 5.10 018/130] x86/insn-eval: Handle return values from the decoder Date: Tue, 12 Jul 2022 20:37:44 +0200 Message-Id: <20220712183247.241740660@linuxfoundation.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220712183246.394947160@linuxfoundation.org> References: <20220712183246.394947160@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Borislav Petkov commit 6e8c83d2a3afbfd5ee019ec720b75a42df515caa upstream. Now that the different instruction-inspecting functions return a value, test that and return early from callers if error has been encountered. While at it, do not call insn_get_modrm() when calling insn_get_displacement() because latter will make sure to call insn_get_modrm() if ModRM hasn't been parsed yet. Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210304174237.31945-6-bp@alien8.de Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- arch/x86/lib/insn-eval.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -928,10 +928,11 @@ static int get_seg_base_limit(struct ins static int get_eff_addr_reg(struct insn *insn, struct pt_regs *regs, int *regoff, long *eff_addr) { - insn_get_modrm(insn); + int ret; - if (!insn->modrm.nbytes) - return -EINVAL; + ret = insn_get_modrm(insn); + if (ret) + return ret; if (X86_MODRM_MOD(insn->modrm.value) != 3) return -EINVAL; @@ -977,14 +978,14 @@ static int get_eff_addr_modrm(struct ins int *regoff, long *eff_addr) { long tmp; + int ret; if (insn->addr_bytes != 8 && insn->addr_bytes != 4) return -EINVAL; - insn_get_modrm(insn); - - if (!insn->modrm.nbytes) - return -EINVAL; + ret = insn_get_modrm(insn); + if (ret) + return ret; if (X86_MODRM_MOD(insn->modrm.value) > 2) return -EINVAL; @@ -1106,18 +1107,21 @@ static int get_eff_addr_modrm_16(struct * @base_offset will have a register, as an offset from the base of pt_regs, * that can be used to resolve the associated segment. * - * -EINVAL on error. + * Negative value on error. */ static int get_eff_addr_sib(struct insn *insn, struct pt_regs *regs, int *base_offset, long *eff_addr) { long base, indx; int indx_offset; + int ret; if (insn->addr_bytes != 8 && insn->addr_bytes != 4) return -EINVAL; - insn_get_modrm(insn); + ret = insn_get_modrm(insn); + if (ret) + return ret; if (!insn->modrm.nbytes) return -EINVAL; @@ -1125,7 +1129,9 @@ static int get_eff_addr_sib(struct insn if (X86_MODRM_MOD(insn->modrm.value) > 2) return -EINVAL; - insn_get_sib(insn); + ret = insn_get_sib(insn); + if (ret) + return ret; if (!insn->sib.nbytes) return -EINVAL; @@ -1194,8 +1200,8 @@ static void __user *get_addr_ref_16(stru short eff_addr; long tmp; - insn_get_modrm(insn); - insn_get_displacement(insn); + if (insn_get_displacement(insn)) + goto out; if (insn->addr_bytes != 2) goto out; @@ -1529,7 +1535,9 @@ bool insn_decode_from_regs(struct insn * insn->addr_bytes = INSN_CODE_SEG_ADDR_SZ(seg_defs); insn->opnd_bytes = INSN_CODE_SEG_OPND_SZ(seg_defs); - insn_get_length(insn); + if (insn_get_length(insn)) + return false; + if (buf_size < insn->length) return false;