From nobody Thu Dec 26 13:22:24 2024 Delivered-To: importer@patchew.org Received-SPF: none (zoho.com: 198.145.21.10 is neither permitted nor denied by domain of lists.01.org) client-ip=198.145.21.10; envelope-from=edk2-devel-bounces@lists.01.org; helo=ml01.01.org; Authentication-Results: mx.zohomail.com; spf=none (zoho.com: 198.145.21.10 is neither permitted nor denied by domain of lists.01.org) smtp.mailfrom=edk2-devel-bounces@lists.01.org Return-Path: Received: from ml01.01.org (ml01.01.org [198.145.21.10]) by mx.zohomail.com with SMTPS id 1505976387890513.2653822856211; Wed, 20 Sep 2017 23:46:27 -0700 (PDT) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id A403621ECCB39; Wed, 20 Sep 2017 23:43:18 -0700 (PDT) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 0BF7021E9461B for ; Wed, 20 Sep 2017 23:43:16 -0700 (PDT) Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Sep 2017 23:46:22 -0700 Received: from shwdeopenpsi014.ccr.corp.intel.com ([10.239.9.13]) by fmsmga006.fm.intel.com with ESMTP; 20 Sep 2017 23:46:21 -0700 X-Original-To: edk2-devel@lists.01.org X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,424,1500966000"; d="scan'208";a="154331010" From: Hao Wu To: edk2-devel@lists.01.org Date: Thu, 21 Sep 2017 14:46:12 +0800 Message-Id: <20170921064617.2628-2-hao.a.wu@intel.com> X-Mailer: git-send-email 2.12.0.windows.1 In-Reply-To: <20170921064617.2628-1-hao.a.wu@intel.com> References: <20170921064617.2628-1-hao.a.wu@intel.com> Subject: [edk2] [PATCH v2 1/6] MdePkg/PrintLib: Fix possible negative value left shift X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Hao Wu , Michael Kinney , Liming Gao MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Errors-To: edk2-devel-bounces@lists.01.org Sender: "edk2-devel" X-ZohoMail: RSF_4 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3D702 Within function InternalPrintLibSPrintMarker(), possible left shift of a negative value is found in: "(*(ArgumentString + 1) << 8)" which involves undefined behavior. Since '*(ArgumentString + 1)' is of type CONST CHAR8 (signed), it will be promoted to type int (signed) during the left shift operation. If '*(ArgumentString + 1)' is a negative value, the behavior will be undefined. According to the C11 spec, Section 6.5.7: > 4 The result of E1 << E2 is E1 left-shifted E2 bit positions; vacated > bits are filled with zeros. If E1 has an unsigned type, the value > of the result is E1 * 2^E2 , reduced modulo one more than the > maximum value representable in the result type. If E1 has a signed > type and nonnegative value, and E1 * 2^E2 is representable in the > result type, then that is the resulting value; otherwise, the > behavior is undefined. This commit explicitly cast '*(ArgumentString + 1)' with UINT8 to resolve this issue. Cc: Steven Shi Cc: Michael Kinney Cc: Liming Gao Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu Reviewed-by: Liming Gao --- MdePkg/Library/BasePrintLib/PrintLibInternal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/MdePkg/Library/BasePrintLib/PrintLibInternal.c b/MdePkg/Librar= y/BasePrintLib/PrintLibInternal.c index cec5b3bc99..28d946472f 100644 --- a/MdePkg/Library/BasePrintLib/PrintLibInternal.c +++ b/MdePkg/Library/BasePrintLib/PrintLibInternal.c @@ -1165,7 +1165,7 @@ BasePrintLibSPrintMarker ( // Copy the string into the output buffer performing the required type= conversions // while (Index < Count) { - ArgumentCharacter =3D ((*ArgumentString & 0xff) | (*(ArgumentString = + 1) << 8)) & ArgumentMask; + ArgumentCharacter =3D ((*ArgumentString & 0xff) | (((UINT8)*(Argumen= tString + 1)) << 8)) & ArgumentMask; =20 LengthToReturn +=3D (1 * BytesPerOutputCharacter); if ((Flags & COUNT_ONLY_NO_PRINT) =3D=3D 0 && Buffer !=3D NULL) { --=20 2.12.0.windows.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel