From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=192.55.52.115; helo=mga14.intel.com; envelope-from=ruiyu.ni@intel.com; receiver=edk2-devel@lists.01.org Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (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 155392239364A for ; Wed, 31 Jan 2018 21:48:30 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Jan 2018 21:54:06 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,443,1511856000"; d="scan'208";a="14169287" Received: from ray-dev.ccr.corp.intel.com (HELO [10.239.9.19]) ([10.239.9.19]) by orsmga007.jf.intel.com with ESMTP; 31 Jan 2018 21:54:05 -0800 From: "Ni, Ruiyu" To: "Wang, Jian J" , "edk2-devel@lists.01.org" Cc: "Yao, Jiewen" , "Dong, Eric" , "Zeng, Star" References: <20180129110950.24212-1-jian.j.wang@intel.com> <741a5893-0537-6bee-17b6-6a60f75fd532@Intel.com> Message-ID: Date: Thu, 1 Feb 2018 13:54:04 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <741a5893-0537-6bee-17b6-6a60f75fd532@Intel.com> Subject: Re: [PATCH] MdeModulePkg/Core: fix feature conflict between NX and NULL detection X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 01 Feb 2018 05:48:30 -0000 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit On 2/1/2018 1:33 PM, Ni, Ruiyu wrote: > On 2/1/2018 9:17 AM, Wang, Jian J wrote: >> You're right. Using a mask or separating the API into two >> (SetMemoryAttributes/ClearMemoryAttributes) >> is much better and can avoid many potential issues. >> >> Regards, >> Jian >> > > For now the patch is good enough to leave NULL pointer detection > feature enabled. > > Reviewed-by: Ruiyu Ni > > >> >>> -----Original Message----- >>> From: Ni, Ruiyu >>> Sent: Tuesday, January 30, 2018 12:38 PM >>> To: Wang, Jian J ; edk2-devel@lists.01.org >>> Cc: Zeng, Star ; Dong, Eric >>> ; Yao, >>> Jiewen >>> Subject: Re: [PATCH] MdeModulePkg/Core: fix feature conflict between >>> NX and >>> NULL detection >>> >>> On 1/29/2018 7:09 PM, Jian J Wang wrote: >>>> If enabled, NX memory protection feature will mark all free memory as >>>> NX (non-executable), including page 0. This will overwrite the >>>> attributes >>>> of page 0 if NULL pointer detection feature is also enabled and then >>>> compromise the functionality of it. The solution is skipping the NX >>>> attributes setting to page 0 if NULL pointer detection feature is >>>> enabled. >>>> >>>> Cc: Star Zeng >>>> Cc: Eric Dong >>>> Cc: Jiewen Yao >>>> Cc: Ruiyu Ni >>>> Contributed-under: TianoCore Contribution Agreement 1.1 >>>> Signed-off-by: Jian J Wang >>>> --- >>>>    MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 20 >>> ++++++++++++++++---- >>>>    1 file changed, 16 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c >>> b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c >>>> index 862593f562..150167bf66 100644 >>>> --- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c >>>> +++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c >>>> @@ -845,10 +845,22 @@ InitializeDxeNxMemoryProtectionPolicy ( >>>> >>>>        Attributes = GetPermissionAttributeForMemoryType >>>> (MemoryMapEntry- >>>> Type); >>>>        if (Attributes != 0) { >>>> -      SetUefiImageMemoryAttributes ( >>>> -        MemoryMapEntry->PhysicalStart, >>>> -        LShiftU64 (MemoryMapEntry->NumberOfPages, EFI_PAGE_SHIFT), >>>> -        Attributes); >>>> +      if (MemoryMapEntry->PhysicalStart == 0 && >>>> +          PcdGet8 (PcdNullPointerDetectionPropertyMask) != 0) { >>>> +        // >>>> +        // Skip page 0 if NULL pointer detection is enabled to >>>> avoid attributes >>>> +        // overwritten. >>>> +        // By the way, could you please add an assertion here? ASSERT (MemoryMapEntry->NumberOfPages != 0); >>>> +        SetUefiImageMemoryAttributes ( >>>> +          MemoryMapEntry->PhysicalStart + EFI_PAGE_SIZE, >>>> +          LShiftU64 (MemoryMapEntry->NumberOfPages - 1, >>>> EFI_PAGE_SHIFT), >>>> +          Attributes); >>>> +      } else { >>>> +        SetUefiImageMemoryAttributes ( >>>> +          MemoryMapEntry->PhysicalStart, >>>> +          LShiftU64 (MemoryMapEntry->NumberOfPages, EFI_PAGE_SHIFT), >>>> +          Attributes); >>>> +      } >>>>        } >>>>        MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, >>> DescriptorSize); >>>>      } >>>> >>> Does this bug expose an API-level issue? >>> SetUefiImageMemoryAttributes () should also accept a Mask value? >>> >>> -- >>> Thanks, >>> Ray > > -- Thanks, Ray