From nobody Thu Dec 26 11:57:36 2024 Delivered-To: importer@patchew.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 1506573151529749.7815161142088; Wed, 27 Sep 2017 21:32:31 -0700 (PDT) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 3CDAA21EC8D1B; Wed, 27 Sep 2017 21:29:13 -0700 (PDT) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (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 362BC21EC8D06 for ; Wed, 27 Sep 2017 21:29:10 -0700 (PDT) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP; 27 Sep 2017 21:32:24 -0700 Received: from shwdeopenpsi014.ccr.corp.intel.com ([10.239.9.13]) by fmsmga002.fm.intel.com with ESMTP; 27 Sep 2017 21:32:22 -0700 X-Original-To: edk2-devel@lists.01.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; Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=192.55.52.43; helo=mga05.intel.com; envelope-from=hao.a.wu@intel.com; receiver=edk2-devel@lists.01.org X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,448,1500966000"; d="scan'208";a="1224629831" From: Hao Wu To: edk2-devel@lists.01.org Date: Thu, 28 Sep 2017 12:32:12 +0800 Message-Id: <20170928043213.20776-5-hao.a.wu@intel.com> X-Mailer: git-send-email 2.12.0.windows.1 In-Reply-To: <20170928043213.20776-1-hao.a.wu@intel.com> References: <20170928043213.20776-1-hao.a.wu@intel.com> Subject: [edk2] [PATCH v3 4/5] MdeModulePkg/DxeNetLib: Fix 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: Eric Dong , Hao Wu , Ye Ting , Wu Jiaxin , Qin Long , Paolo Bonzini , Fu Siyuan , Star Zeng 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=3D698 Within function NetRandomInitSeed(), left shift a negative value is used in: "~Time.Hour << 24" which involves undefined behavior. Since Time.Hour is of type UINT8 (range from 0 to 23), hence ~Time.Hour will be a negative value (of type int, signed). 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 will remove the '~' operator before 'Time.Hour', since it seems like an implementation choice for generating the seed. Cc: Steven Shi Cc: Fu Siyuan Cc: Ye Ting Cc: Wu Jiaxin Cc: Qin Long Cc: Star Zeng Cc: Eric Dong Cc: Paolo Bonzini Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu Reviewed-by: Fu Siyuan Reviewed-by: Wu Jiaxin Reviewed-by: Ye Ting =20 --- MdeModulePkg/Library/DxeNetLib/DxeNetLib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c b/MdeModulePkg/Libr= ary/DxeNetLib/DxeNetLib.c index 7cd7e3aca0..1ee77fe036 100644 --- a/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c +++ b/MdeModulePkg/Library/DxeNetLib/DxeNetLib.c @@ -872,7 +872,7 @@ NetRandomInitSeed ( UINT64 MonotonicCount; =20 gRT->GetTime (&Time, NULL); - Seed =3D (~Time.Hour << 24 | Time.Day << 16 | Time.Minute << 8 | Time.Se= cond); + Seed =3D (Time.Hour << 24 | Time.Day << 16 | Time.Minute << 8 | Time.Sec= ond); Seed ^=3D Time.Nanosecond; Seed ^=3D Time.Year << 7; =20 --=20 2.12.0.windows.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel