From nobody Sat Nov 2 16:31:45 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.zoho.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 1487995532129803.52768880492; Fri, 24 Feb 2017 20:05:32 -0800 (PST) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 50E5E8219F; Fri, 24 Feb 2017 20:05:27 -0800 (PST) Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) (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 1851D8219B for ; Fri, 24 Feb 2017 20:05:25 -0800 (PST) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga104.jf.intel.com with ESMTP; 24 Feb 2017 20:05:25 -0800 Received: from shwdeopenpsi014.ccr.corp.intel.com ([10.239.9.13]) by fmsmga004.fm.intel.com with ESMTP; 24 Feb 2017 20:05:23 -0800 X-Original-To: edk2-devel@lists.01.org X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,202,1484035200"; d="scan'208";a="229518348" From: Hao Wu To: edk2-devel@lists.01.org Date: Sat, 25 Feb 2017 12:05:12 +0800 Message-Id: <1487995514-7628-5-git-send-email-hao.a.wu@intel.com> X-Mailer: git-send-email 1.9.5.msysgit.0 In-Reply-To: <1487995514-7628-1-git-send-email-hao.a.wu@intel.com> References: <1487995514-7628-1-git-send-email-hao.a.wu@intel.com> Subject: [edk2] [PATCH v3 4/6] NetworkPkg: Refine type cast for pointer subtraction X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Hao Wu , Siyuan Fu , Jiaxin Wu 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" For pointer subtraction, the result is of type "ptrdiff_t". According to the C11 standard (Committee Draft - April 12, 2011): "When two pointers are subtracted, both shall point to elements of the same array object, or one past the last element of the array object; the result is the difference of the subscripts of the two array elements. The size of the result is implementation-defined, and its type (a signed integer type) is ptrdiff_t defined in the header. If the result is not representable in an object of that type, the behavior is undefined." In our codes, there are cases that the pointer subtraction is not performed by pointers to elements of the same array object. This might lead to potential issues, since the behavior is undefined according to C11 standard. Also, since the size of type "ptrdiff_t" is implementation-defined. Some static code checkers may warn that the pointer subtraction might underflow first and then being cast to a bigger size. For example: UINT8 *Ptr1, *Ptr2; UINTN PtrDiff; ... PtrDiff =3D (UINTN) (Ptr1 - Ptr2); The commit will refine the pointer subtraction expressions by casting each pointer to UINTN first and then perform the subtraction: PtrDiff =3D (UINTN) Ptr1 - (UINTN) Ptr2; Cc: Siyuan Fu Cc: Jiaxin Wu Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Hao Wu Acked-by: Laszlo Ersek Reviewed-by: Fu Siyuan Reviewed-by: Wu Jiaxin --- NetworkPkg/HttpDxe/HttpImpl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/NetworkPkg/HttpDxe/HttpImpl.c b/NetworkPkg/HttpDxe/HttpImpl.c index 745832b..1f7a4fa 100644 --- a/NetworkPkg/HttpDxe/HttpImpl.c +++ b/NetworkPkg/HttpDxe/HttpImpl.c @@ -1342,7 +1342,7 @@ HttpResponseWorker ( // We receive part of header of next HTTP msg. // if (HttpInstance->NextMsg !=3D NULL) { - HttpMsg->BodyLength =3D MIN ((UINTN) (HttpInstance->NextMsg - (CHAR8= *) Fragment.Bulk), HttpMsg->BodyLength); + HttpMsg->BodyLength =3D MIN ((UINTN) HttpInstance->NextMsg - (UINTN)= Fragment.Bulk, HttpMsg->BodyLength); CopyMem (HttpMsg->Body, Fragment.Bulk, HttpMsg->BodyLength); =20 HttpInstance->CacheLen =3D Fragment.Len - HttpMsg->BodyLength; @@ -1360,7 +1360,7 @@ HttpResponseWorker ( CopyMem (HttpInstance->CacheBody, Fragment.Bulk + HttpMsg->BodyLen= gth, HttpInstance->CacheLen); HttpInstance->CacheOffset =3D 0; =20 - HttpInstance->NextMsg =3D HttpInstance->CacheBody + (UINTN) (HttpI= nstance->NextMsg - (CHAR8 *) (Fragment.Bulk + HttpMsg->BodyLength)); + HttpInstance->NextMsg =3D HttpInstance->CacheBody + ((UINTN) HttpI= nstance->NextMsg - (UINTN) (Fragment.Bulk + HttpMsg->BodyLength)); } } else { HttpMsg->BodyLength =3D MIN (Fragment.Len, (UINT32) HttpMsg->BodyLen= gth); --=20 1.9.5.msysgit.0 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel