From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=192.55.52.120; helo=mga04.intel.com; envelope-from=jiewen.yao@intel.com; receiver=edk2-devel@lists.01.org Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) (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 4584A21E1B752 for ; Mon, 25 Sep 2017 01:47:32 -0700 (PDT) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Sep 2017 01:50:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,435,1500966000"; d="scan'208";a="315805500" Received: from fmsmsx106.amr.corp.intel.com ([10.18.124.204]) by fmsmga004.fm.intel.com with ESMTP; 25 Sep 2017 01:50:43 -0700 Received: from fmsmsx125.amr.corp.intel.com (10.18.125.40) by FMSMSX106.amr.corp.intel.com (10.18.124.204) with Microsoft SMTP Server (TLS) id 14.3.319.2; Mon, 25 Sep 2017 01:50:43 -0700 Received: from shsmsx101.ccr.corp.intel.com (10.239.4.153) by FMSMSX125.amr.corp.intel.com (10.18.125.40) with Microsoft SMTP Server (TLS) id 14.3.319.2; Mon, 25 Sep 2017 01:50:42 -0700 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.175]) by SHSMSX101.ccr.corp.intel.com ([169.254.1.159]) with mapi id 14.03.0319.002; Mon, 25 Sep 2017 16:50:40 +0800 From: "Yao, Jiewen" To: "Wang, Jian J" , "edk2-devel@lists.01.org" CC: "Zeng, Star" , "Dong, Eric" , Laszlo Ersek , "Kinney, Michael D" , "Justen, Jordan L" , "Wolman, Ayellet" Thread-Topic: [PATCH v2 2/6] MdeModulePkg/DxeIpl: Implement NULL pointer detection Thread-Index: AQHTMpljxyaF1eQT702ZquneuJ//aKLFUReQ Date: Mon, 25 Sep 2017 08:50:40 +0000 Message-ID: <74D8A39837DF1E4DA445A8C0B3885C503A9C1BCE@shsmsx102.ccr.corp.intel.com> References: <20170921052032.13652-1-jian.j.wang@intel.com> <20170921052032.13652-3-jian.j.wang@intel.com> In-Reply-To: <20170921052032.13652-3-jian.j.wang@intel.com> Accept-Language: zh-CN, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.0.0.116 dlp-reaction: no-action x-originating-ip: [10.239.127.40] MIME-Version: 1.0 Subject: Re: [PATCH v2 2/6] MdeModulePkg/DxeIpl: Implement NULL pointer detection 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: , X-List-Received-Date: Mon, 25 Sep 2017 08:47:33 -0000 Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi I do not think NULL pointer is related to NX. As long as NullPointer PCD is true and IA32PAE is supported, we can build p= age table. + BuildPageTablesIa32Pae =3D (BOOLEAN) (IsIa32PaeSupport () + && IsExecuteDisableBitAvailable () + && (PcdGetBool (PcdSetNxForStack) + || IsNullDetectionEnabled ()))= ; > -----Original Message----- > From: Wang, Jian J > Sent: Thursday, September 21, 2017 1:20 PM > To: edk2-devel@lists.01.org > Cc: Zeng, Star ; Dong, Eric ; L= aszlo > Ersek ; Yao, Jiewen ; Kinney, > Michael D ; Justen, Jordan L > ; Wolman, Ayellet > Subject: [PATCH v2 2/6] MdeModulePkg/DxeIpl: Implement NULL pointer > detection >=20 > NULL pointer detection is done by making use of paging mechanism of CPU. > During page table setup, if enabled, the first 4-K page (0-4095) will be > marked as NOT PRESENT. Any code which unintentionally access memory > between > 0-4095 will trigger a Page Fault exception which warns users that there's > potential illegal code in BIOS. >=20 > This also means that legacy code which has to access memory between 0-409= 5 > should be cautious to temporarily disable this feature before the access > and re-enable it afterwards; or disalbe this feature at all. >=20 > Cc: Star Zeng > Cc: Eric Dong > Cc: Laszlo Ersek > Cc: Jiewen Yao > Cc: Michael Kinney > Cc: Jordan Justen > Cc: Ayellet Wolman > Suggested-by: Ayellet Wolman > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Jian J Wang > --- > MdeModulePkg/Core/DxeIplPeim/DxeIpl.h | 25 +++++++++ > MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf | 1 + > MdeModulePkg/Core/DxeIplPeim/DxeLoad.c | 65 > ++++++++++++++++++++++++ > MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c | 11 +++- > MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c | 2 + > MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 31 ++++++++--- > 6 files changed, 126 insertions(+), 9 deletions(-) >=20 > diff --git a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.h > b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.h > index 72d2532f50..1654bcd2dc 100644 > --- a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.h > +++ b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.h > @@ -240,4 +240,29 @@ Decompress ( > OUT UINTN *OutputSize > ); >=20 > +/** > + Clear legacy memory located at the first 4K-page. > + > + This function traverses the whole HOB list to check if memory from 0 = to 4095 > + exists and has not been allocated, and then clear it if so. > + > + @param HoStart The start of HobList passed to DxeCore. > + > +**/ > +VOID > +ClearLegacyMemory ( > + IN VOID *HobStart > + ); > + > +/** > + Return configure status of NULL pointer detection feature > + > + @return TRUE NULL pointer detection feature is enabled > + @return FALSE NULL pointer detection feature is disabled > +**/ > +BOOLEAN > +IsNullDetectionEnabled ( > + VOID > + ); > + > #endif > diff --git a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf > b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf > index c54afe4aa6..9d0e76a293 100644 > --- a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf > +++ b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf > @@ -115,6 +115,7 @@ > [Pcd.IA32,Pcd.X64] > gEfiMdeModulePkgTokenSpaceGuid.PcdUse1GPageTable > ## SOMETIMES_CONSUMES >=20 > gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask > ## CONSUMES > + gEfiMdeModulePkgTokenSpaceGuid.PcdNullPointerDetectionPropertyMask > ## CONSUMES >=20 > [Pcd.IA32,Pcd.X64,Pcd.ARM,Pcd.AARCH64] > gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack ## > SOMETIMES_CONSUMES > diff --git a/MdeModulePkg/Core/DxeIplPeim/DxeLoad.c > b/MdeModulePkg/Core/DxeIplPeim/DxeLoad.c > index 50b5440d15..0a71b1f3de 100644 > --- a/MdeModulePkg/Core/DxeIplPeim/DxeLoad.c > +++ b/MdeModulePkg/Core/DxeIplPeim/DxeLoad.c > @@ -825,3 +825,68 @@ UpdateStackHob ( > Hob.Raw =3D GET_NEXT_HOB (Hob); > } > } > + > +/** > + Clear legacy memory located at the first 4K-page, if available. > + > + This function traverses the whole HOB list to check if memory from 0 = to 4095 > + exists and has not been allocated, and then clear it if so. > + > + @param HoStart The start of HobList passed to > DxeCore. > + > +**/ > +VOID > +ClearLegacyMemory ( > + IN VOID *HobStart > + ) > +{ > + EFI_PEI_HOB_POINTERS RscHob; > + EFI_PEI_HOB_POINTERS MemHob; > + BOOLEAN DoClear; > + > + RscHob.Raw =3D HobStart; > + MemHob.Raw =3D HobStart; > + DoClear =3D FALSE; > + > + // > + // Check if page 0 exists and free > + // > + while ((RscHob.Raw =3D GetNextHob (EFI_HOB_TYPE_RESOURCE_DESCRIPTOR, > + RscHob.Raw)) !=3D NULL) { > + if (RscHob.ResourceDescriptor->ResourceType =3D=3D > EFI_RESOURCE_SYSTEM_MEMORY && > + RscHob.ResourceDescriptor->PhysicalStart =3D=3D 0) { > + DoClear =3D TRUE; > + // > + // Make sure memory at 0-4095 has not been allocated. > + // > + while ((MemHob.Raw =3D GetNextHob > (EFI_HOB_TYPE_MEMORY_ALLOCATION, > + MemHob.Raw)) !=3D NULL) { > + if (MemHob.MemoryAllocation->AllocDescriptor.MemoryBaseAddress > + < EFI_PAGE_SIZE) { > + DoClear =3D FALSE; > + break; > + } > + MemHob.Raw =3D GET_NEXT_HOB (MemHob); > + } > + break; > + } > + RscHob.Raw =3D GET_NEXT_HOB (RscHob); > + } > + > + if (DoClear) { > + DEBUG ((DEBUG_INFO, "Clearing first 4K-page!\r\n")); > + SetMem (NULL, EFI_PAGE_SIZE, 0); > + } > + > + return; > +} > + > +BOOLEAN > +IsNullDetectionEnabled ( > + VOID > + ) > +{ > + return (((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) !=3D 0= ) ? > + TRUE : FALSE); > +} > + > diff --git a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c > b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c > index 1957326caf..503cf88382 100644 > --- a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c > +++ b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c > @@ -123,7 +123,9 @@ Create4GPageTablesIa32Pae ( > PageDirectoryPointerEntry->Bits.Present =3D 1; >=20 > for (IndexOfPageDirectoryEntries =3D 0; IndexOfPageDirectoryEntries = < 512; > IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PhysicalAddress +=3D > SIZE_2MB) { > - if ((PhysicalAddress < StackBase + StackSize) && ((PhysicalAddress= + > SIZE_2MB) > StackBase)) { > + if ((IsNullDetectionEnabled () && PhysicalAddress =3D=3D 0) > + || ((PhysicalAddress < StackBase + StackSize) > + && ((PhysicalAddress + SIZE_2MB) > StackBase))) { > // > // Need to split this 2M page that covers stack range. > // > @@ -240,6 +242,8 @@ HandOffToDxeCore ( > EFI_PEI_VECTOR_HANDOFF_INFO_PPI *VectorHandoffInfoPpi; > BOOLEAN BuildPageTablesIa32Pae; >=20 > + ClearLegacyMemory (HobList.Raw); > + > Status =3D PeiServicesAllocatePages (EfiBootServicesData, EFI_SIZE_TO_= PAGES > (STACK_SIZE), &BaseOfStack); > ASSERT_EFI_ERROR (Status); >=20 > @@ -379,7 +383,10 @@ HandOffToDxeCore ( > TopOfStack =3D (EFI_PHYSICAL_ADDRESS) (UINTN) ALIGN_POINTER > (TopOfStack, CPU_STACK_ALIGNMENT); >=20 > PageTables =3D 0; > - BuildPageTablesIa32Pae =3D (BOOLEAN) (PcdGetBool (PcdSetNxForStack) = && > IsIa32PaeSupport () && IsExecuteDisableBitAvailable ()); > + BuildPageTablesIa32Pae =3D (BOOLEAN) (IsIa32PaeSupport () > + && IsExecuteDisableBitAvailable > () > + && (PcdGetBool > (PcdSetNxForStack) > + || IsNullDetectionEnabled > ())); > if (BuildPageTablesIa32Pae) { > PageTables =3D Create4GPageTablesIa32Pae (BaseOfStack, STACK_SIZE)= ; > EnableExecuteDisableBit (); > diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c > b/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c > index 6488880eab..d93a9c5a2d 100644 > --- a/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c > +++ b/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c > @@ -42,6 +42,8 @@ HandOffToDxeCore ( > EFI_VECTOR_HANDOFF_INFO *VectorInfo; > EFI_PEI_VECTOR_HANDOFF_INFO_PPI *VectorHandoffInfoPpi; >=20 > + ClearLegacyMemory (HobList.Raw); > + > // > // Get Vector Hand-off Info PPI and build Guided HOB > // > diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c > b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c > index 48150be4e1..80c1821eca 100644 > --- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c > +++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c > @@ -90,8 +90,16 @@ Split2MPageTo4K ( > // > PageTableEntry->Uint64 =3D (UINT64) PhysicalAddress4K | AddressEncMa= sk; > PageTableEntry->Bits.ReadWrite =3D 1; > - PageTableEntry->Bits.Present =3D 1; > - if ((PhysicalAddress4K >=3D StackBase) && (PhysicalAddress4K < Stack= Base + > StackSize)) { > + > + if (IsNullDetectionEnabled () && PhysicalAddress4K =3D=3D 0) { > + PageTableEntry->Bits.Present =3D 0; > + } else { > + PageTableEntry->Bits.Present =3D 1; > + } > + > + if (PcdGetBool (PcdSetNxForStack) > + && (PhysicalAddress4K >=3D StackBase) > + && (PhysicalAddress4K < StackBase + StackSize)) { > // > // Set Nx bit for stack. > // > @@ -137,9 +145,12 @@ Split1GPageTo2M ( >=20 > PhysicalAddress2M =3D PhysicalAddress; > for (IndexOfPageDirectoryEntries =3D 0; IndexOfPageDirectoryEntries < = 512; > IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PhysicalAddress2M += =3D > SIZE_2MB) { > - if ((PhysicalAddress2M < StackBase + StackSize) && ((PhysicalAddress= 2M + > SIZE_2MB) > StackBase)) { > + if ((IsNullDetectionEnabled () && PhysicalAddress2M =3D=3D 0) > + || (PcdGetBool (PcdSetNxForStack) > + && (PhysicalAddress2M < StackBase + StackSize) > + && ((PhysicalAddress2M + SIZE_2MB) > StackBase))) { > // > - // Need to split this 2M page that covers stack range. > + // Need to split this 2M page that covers NULL or stack range. > // > Split2MPageTo4K (PhysicalAddress2M, (UINT64 *) PageDirectoryEntry, > StackBase, StackSize); > } else { > @@ -279,7 +290,10 @@ CreateIdentityMappingPageTables ( > PageDirectory1GEntry =3D (VOID *) PageDirectoryPointerEntry; >=20 > for (IndexOfPageDirectoryEntries =3D 0; IndexOfPageDirectoryEntrie= s < 512; > IndexOfPageDirectoryEntries++, PageDirectory1GEntry++, PageAddress +=3D > SIZE_1GB) { > - if (PcdGetBool (PcdSetNxForStack) && (PageAddress < StackBase + > StackSize) && ((PageAddress + SIZE_1GB) > StackBase)) { > + if ((IsNullDetectionEnabled () && PageAddress =3D=3D 0) > + || (PcdGetBool (PcdSetNxForStack) > + && (PageAddress < StackBase + StackSize) > + && ((PageAddress + SIZE_1GB) > StackBase))) { > Split1GPageTo2M (PageAddress, (UINT64 *) PageDirectory1GEntry, > StackBase, StackSize); > } else { > // > @@ -308,9 +322,12 @@ CreateIdentityMappingPageTables ( > PageDirectoryPointerEntry->Bits.Present =3D 1; >=20 > for (IndexOfPageDirectoryEntries =3D 0; IndexOfPageDirectoryEntr= ies < > 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PageAddress += =3D > SIZE_2MB) { > - if (PcdGetBool (PcdSetNxForStack) && (PageAddress < StackBase = + > StackSize) && ((PageAddress + SIZE_2MB) > StackBase)) { > + if ((IsNullDetectionEnabled () && PageAddress =3D=3D 0) > + || (PcdGetBool (PcdSetNxForStack) > + && (PageAddress < StackBase + StackSize) > + && ((PageAddress + SIZE_2MB) > StackBase))) { > // > - // Need to split this 2M page that covers stack range. > + // Need to split this 2M page that covers NULL or stack rang= e. > // > Split2MPageTo4K (PageAddress, (UINT64 *) PageDirectoryEntry, > StackBase, StackSize); > } else { > -- > 2.14.1.windows.1