From nobody Tue Feb 10 07:57:48 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1763785168935509.2893895978035; Fri, 21 Nov 2025 20:19:28 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vMdDI-0002sb-DM; Fri, 21 Nov 2025 21:19:01 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vMdD3-0002l8-A7; Fri, 21 Nov 2025 21:18:45 -0500 Received: from isrv.corpit.ru ([212.248.84.144]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vMdBt-0000UV-CS; Fri, 21 Nov 2025 21:18:41 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 7F31316C723; Fri, 21 Nov 2025 16:52:00 +0300 (MSK) Received: from think4mjt.tls.msk.ru (mjtthink.wg.tls.msk.ru [192.168.177.146]) by tsrv.corpit.ru (Postfix) with ESMTP id C73863219BF; Fri, 21 Nov 2025 16:52:08 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Paolo Bonzini , Michael Tokarev Subject: [Stable-10.1.3 74/76] target/i386/tcg: validate segment registers Date: Fri, 21 Nov 2025 16:51:52 +0300 Message-ID: <20251121135201.1114964-74-mjt@tls.msk.ru> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=212.248.84.144; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, T_SPF_HELO_TEMPERROR=0.01, T_SPF_TEMPERROR=0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1763785170967018900 Content-Type: text/plain; charset="utf-8" From: Paolo Bonzini Correctly reject invalid segment registers, including CS when used as the destination of a MOV. Ignore the REX prefix as well. Fixes: 5e9e21bcc4d ("target/i386: move 60-BF opcodes to new decoder", 2024-= 05-07) Cc: qemu-stable@nongnu.org Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3195 Signed-off-by: Paolo Bonzini (cherry picked from commit ebb46ba6a4a20d393a6889c21e8a80dabab4cc8e) Signed-off-by: Michael Tokarev diff --git a/target/i386/tcg/decode-new.c.inc b/target/i386/tcg/decode-new.= c.inc index 805cfd08e8..0f8c5d1693 100644 --- a/target/i386/tcg/decode-new.c.inc +++ b/target/i386/tcg/decode-new.c.inc @@ -2059,7 +2059,12 @@ static bool decode_op(DisasContext *s, CPUX86State *= env, X86DecodedInsn *decode, =20 case X86_TYPE_S: /* reg selects a segment register */ op->unit =3D X86_OP_SEG; - goto get_reg; + op->n =3D (get_modrm(s, env) >> 3) & 7; + /* Values outside [CDEFGS]S, as well as storing to CS, are invalid= . */ + if (op->n >=3D 6 || (op->n =3D=3D R_CS && op =3D=3D &decode->op[0]= )) { + return false; + } + break; =20 case X86_TYPE_P: op->unit =3D X86_OP_MMX; --=20 2.47.3