| Message ID | 1488133805-4773-7-git-send-email-ard.biesheuvel@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | RFC: increased memory protection | expand |
Ard: I have minor comment. GetPermissionAttributeForMemoryType() function header comment doesn't match its definition, and IsInSmm() has no function header. Thanks Liming >-----Original Message----- >From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org] >Sent: Monday, February 27, 2017 2:30 AM >To: edk2-devel@lists.01.org; Yao, Jiewen <jiewen.yao@intel.com>; >leif.lindholm@linaro.org >Cc: afish@apple.com; Kinney, Michael D <michael.d.kinney@intel.com>; Gao, >Liming <liming.gao@intel.com>; lersek@redhat.com; Tian, Feng ><feng.tian@intel.com>; Zeng, Star <star.zeng@intel.com>; Ard Biesheuvel ><ard.biesheuvel@linaro.org> >Subject: [PATCH v3 6/6] MdeModulePkg/DxeCore: implement memory >protection policy > >This implements a DXE memory protection policy that ensure that regions >that don't require executable permissions are mapped with the non-exec >attribute set. > >First of all, it iterates over all entries in the UEFI memory map, and >removes executable permissions according to the configured DXE memory >protection policy, as recorded in PcdDxeMemoryProtectionPolicy. > >Secondly, it sets or clears the non-executable attribute when allocating >or freeing pages, both for page based or pool based allocations. > >Note that this complements the image protection facility, which applies >strict permissions to BootServicesCode/RuntimeServicesCode regions when >the section alignment allows it. The memory protection configured by this >patch operates on non-code regions only. > >Contributed-under: TianoCore Contribution Agreement 1.0 >Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> >--- > MdeModulePkg/Core/Dxe/DxeMain.h | 24 ++ > MdeModulePkg/Core/Dxe/DxeMain.inf | 1 + > MdeModulePkg/Core/Dxe/Mem/Page.c | 4 + > MdeModulePkg/Core/Dxe/Mem/Pool.c | 7 + > MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 306 >+++++++++++++++++++- > 5 files changed, 341 insertions(+), 1 deletion(-) > >diff --git a/MdeModulePkg/Core/Dxe/DxeMain.h >b/MdeModulePkg/Core/Dxe/DxeMain.h >index b14be9a74d8e..5668c1f2d648 100644 >--- a/MdeModulePkg/Core/Dxe/DxeMain.h >+++ b/MdeModulePkg/Core/Dxe/DxeMain.h >@@ -2949,4 +2949,28 @@ MemoryProtectionExitBootServicesCallback ( > VOID > ); > >+/** >+ Manage memory permission attributes on a memory range, according to >the >+ configured DXE memory protection policy. >+ >+ @param OldType The old memory type of the range >+ @param NewType The new memory type of the range >+ @param Memory The base address of the range >+ @param Length The size of the range (in bytes) >+ >+ @return EFI_SUCCESS If the the CPU arch protocol is not installed yet >+ @return EFI_SUCCESS If no DXE memory protection policy has been >configured >+ @return EFI_SUCCESS If OldType and NewType use the same permission >attributes >+ @return other Return value of gCpu->SetMemoryAttributes() >+ >+**/ >+EFI_STATUS >+EFIAPI >+ApplyMemoryProtectionPolicy ( >+ IN EFI_MEMORY_TYPE OldType, >+ IN EFI_MEMORY_TYPE NewType, >+ IN EFI_PHYSICAL_ADDRESS Memory, >+ IN UINT64 Length >+ ); >+ > #endif >diff --git a/MdeModulePkg/Core/Dxe/DxeMain.inf >b/MdeModulePkg/Core/Dxe/DxeMain.inf >index 371e91cb0d7e..30d5984f7c1f 100644 >--- a/MdeModulePkg/Core/Dxe/DxeMain.inf >+++ b/MdeModulePkg/Core/Dxe/DxeMain.inf >@@ -191,6 +191,7 @@ [Pcd] > gEfiMdeModulePkgTokenSpaceGuid.PcdMemoryProfileDriverPath >## CONSUMES > gEfiMdeModulePkgTokenSpaceGuid.PcdPropertiesTableEnable ## >CONSUMES > gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy ## >CONSUMES >+ gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy >## CONSUMES > > # [Hob] > # RESOURCE_DESCRIPTOR ## CONSUMES >diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c >b/MdeModulePkg/Core/Dxe/Mem/Page.c >index bda4f6397e91..86874906de58 100644 >--- a/MdeModulePkg/Core/Dxe/Mem/Page.c >+++ b/MdeModulePkg/Core/Dxe/Mem/Page.c >@@ -1344,6 +1344,8 @@ CoreAllocatePages ( > NULL > ); > InstallMemoryAttributesTableOnMemoryAllocation (MemoryType); >+ ApplyMemoryProtectionPolicy (EfiConventionalMemory, MemoryType, >*Memory, >+ EFI_PAGES_TO_SIZE (NumberOfPages)); > } > return Status; > } >@@ -1460,6 +1462,8 @@ CoreFreePages ( > NULL > ); > InstallMemoryAttributesTableOnMemoryAllocation (MemoryType); >+ ApplyMemoryProtectionPolicy (MemoryType, EfiConventionalMemory, >Memory, >+ EFI_PAGES_TO_SIZE (NumberOfPages)); > } > return Status; > } >diff --git a/MdeModulePkg/Core/Dxe/Mem/Pool.c >b/MdeModulePkg/Core/Dxe/Mem/Pool.c >index 410615e0dee9..63b9983b88b5 100644 >--- a/MdeModulePkg/Core/Dxe/Mem/Pool.c >+++ b/MdeModulePkg/Core/Dxe/Mem/Pool.c >@@ -305,6 +305,10 @@ CoreAllocatePoolPagesI ( > Buffer = CoreAllocatePoolPages (PoolType, NoPages, Granularity); > CoreReleaseMemoryLock (); > >+ if (Buffer != NULL) { >+ ApplyMemoryProtectionPolicy (EfiConventionalMemory, PoolType, >+ (EFI_PHYSICAL_ADDRESS)(UINTN)Buffer, EFI_PAGES_TO_SIZE >(NoPages)); >+ } > return Buffer; > } > >@@ -555,6 +559,9 @@ CoreFreePoolPagesI ( > CoreAcquireMemoryLock (); > CoreFreePoolPages (Memory, NoPages); > CoreReleaseMemoryLock (); >+ >+ ApplyMemoryProtectionPolicy (PoolType, EfiConventionalMemory, >+ (EFI_PHYSICAL_ADDRESS)(UINTN)Memory, EFI_PAGES_TO_SIZE >(NoPages)); > } > > /** >diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c >b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c >index 46d88463d417..f2a69a3d0df9 100644 >--- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c >+++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c >@@ -64,6 +64,12 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY >KIND, EITHER EXPRESS OR IMPLIED. > #define DO_NOT_PROTECT 0x00000000 > #define PROTECT_IF_ALIGNED_ELSE_ALLOW 0x00000001 > >+#define MEMORY_TYPE_OS_RESERVED_MIN 0x80000000 >+#define MEMORY_TYPE_OEM_RESERVED_MIN 0x70000000 >+ >+#define PREVIOUS_MEMORY_DESCRIPTOR(MemoryDescriptor, Size) \ >+ ((EFI_MEMORY_DESCRIPTOR *)((UINT8 *)(MemoryDescriptor) - (Size))) >+ > UINT32 mImageProtectionPolicy; > > /** >@@ -647,6 +653,210 @@ UnprotectUefiImage ( > } > > /** >+ Return the EFI memory permission attribute associated with memory >+ type 'Type' under the configured DXE memory protection policy. >+**/ >+STATIC >+UINT64 >+GetPermissionAttributeForMemoryType ( >+ IN EFI_MEMORY_TYPE MemoryType >+ ) >+{ >+ UINT64 TestBit; >+ >+ if ((UINT32) MemoryType >= MEMORY_TYPE_OS_RESERVED_MIN) { >+ TestBit = BIT63; >+ } else if ((UINT32) MemoryType >= MEMORY_TYPE_OEM_RESERVED_MIN) >{ >+ TestBit = BIT62; >+ } else { >+ TestBit = LShiftU64 (1, MemoryType); >+ } >+ >+ if ((PcdGet64 (PcdDxeNxMemoryProtectionPolicy) & TestBit) != 0) { >+ return EFI_MEMORY_XP; >+ } else { >+ return 0; >+ } >+} >+ >+/** >+ Sort memory map entries based upon PhysicalStart, from low to high. >+ >+ @param MemoryMap A pointer to the buffer in which firmware >places >+ the current memory map. >+ @param MemoryMapSize Size, in bytes, of the MemoryMap buffer. >+ @param DescriptorSize Size, in bytes, of an individual >EFI_MEMORY_DESCRIPTOR. >+**/ >+STATIC >+VOID >+SortMemoryMap ( >+ IN OUT EFI_MEMORY_DESCRIPTOR *MemoryMap, >+ IN UINTN MemoryMapSize, >+ IN UINTN DescriptorSize >+ ) >+{ >+ EFI_MEMORY_DESCRIPTOR *MemoryMapEntry; >+ EFI_MEMORY_DESCRIPTOR *NextMemoryMapEntry; >+ EFI_MEMORY_DESCRIPTOR *MemoryMapEnd; >+ EFI_MEMORY_DESCRIPTOR TempMemoryMap; >+ >+ MemoryMapEntry = MemoryMap; >+ NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, >DescriptorSize); >+ MemoryMapEnd = (EFI_MEMORY_DESCRIPTOR *) ((UINT8 *) MemoryMap >+ MemoryMapSize); >+ while (MemoryMapEntry < MemoryMapEnd) { >+ while (NextMemoryMapEntry < MemoryMapEnd) { >+ if (MemoryMapEntry->PhysicalStart > NextMemoryMapEntry- >>PhysicalStart) { >+ CopyMem (&TempMemoryMap, MemoryMapEntry, >sizeof(EFI_MEMORY_DESCRIPTOR)); >+ CopyMem (MemoryMapEntry, NextMemoryMapEntry, >sizeof(EFI_MEMORY_DESCRIPTOR)); >+ CopyMem (NextMemoryMapEntry, &TempMemoryMap, >sizeof(EFI_MEMORY_DESCRIPTOR)); >+ } >+ >+ NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR >(NextMemoryMapEntry, DescriptorSize); >+ } >+ >+ MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, >DescriptorSize); >+ NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR >(MemoryMapEntry, DescriptorSize); >+ } >+} >+ >+/** >+ Merge adjacent memory map entries if they use the same memory >protection policy >+ >+ @param[in, out] MemoryMap A pointer to the buffer in which >firmware places >+ the current memory map. >+ @param[in, out] MemoryMapSize A pointer to the size, in bytes, of >the >+ MemoryMap buffer. On input, this is the size of >+ the current memory map. On output, >+ it is the size of new memory map after merge. >+ @param[in] DescriptorSize Size, in bytes, of an individual >EFI_MEMORY_DESCRIPTOR. >+**/ >+STATIC >+VOID >+MergeMemoryMapForProtectionPolicy ( >+ IN OUT EFI_MEMORY_DESCRIPTOR *MemoryMap, >+ IN OUT UINTN *MemoryMapSize, >+ IN UINTN DescriptorSize >+ ) >+{ >+ EFI_MEMORY_DESCRIPTOR *MemoryMapEntry; >+ EFI_MEMORY_DESCRIPTOR *MemoryMapEnd; >+ UINT64 MemoryBlockLength; >+ EFI_MEMORY_DESCRIPTOR *NewMemoryMapEntry; >+ EFI_MEMORY_DESCRIPTOR *NextMemoryMapEntry; >+ UINT64 Attributes; >+ >+ SortMemoryMap (MemoryMap, *MemoryMapSize, DescriptorSize); >+ >+ MemoryMapEntry = MemoryMap; >+ NewMemoryMapEntry = MemoryMap; >+ MemoryMapEnd = (EFI_MEMORY_DESCRIPTOR *) ((UINT8 *) MemoryMap >+ *MemoryMapSize); >+ while ((UINTN)MemoryMapEntry < (UINTN)MemoryMapEnd) { >+ CopyMem (NewMemoryMapEntry, MemoryMapEntry, >sizeof(EFI_MEMORY_DESCRIPTOR)); >+ NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR >(MemoryMapEntry, DescriptorSize); >+ >+ do { >+ MemoryBlockLength = (UINT64) >(EFI_PAGES_TO_SIZE((UINTN)MemoryMapEntry->NumberOfPages)); >+ Attributes = GetPermissionAttributeForMemoryType >(MemoryMapEntry->Type); >+ >+ if (((UINTN)NextMemoryMapEntry < (UINTN)MemoryMapEnd) && >+ Attributes == GetPermissionAttributeForMemoryType >(NextMemoryMapEntry->Type) && >+ ((MemoryMapEntry->PhysicalStart + MemoryBlockLength) == >NextMemoryMapEntry->PhysicalStart)) { >+ MemoryMapEntry->NumberOfPages += NextMemoryMapEntry- >>NumberOfPages; >+ if (NewMemoryMapEntry != MemoryMapEntry) { >+ NewMemoryMapEntry->NumberOfPages += NextMemoryMapEntry- >>NumberOfPages; >+ } >+ >+ NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR >(NextMemoryMapEntry, DescriptorSize); >+ continue; >+ } else { >+ MemoryMapEntry = PREVIOUS_MEMORY_DESCRIPTOR >(NextMemoryMapEntry, DescriptorSize); >+ break; >+ } >+ } while (TRUE); >+ >+ MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, >DescriptorSize); >+ NewMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR >(NewMemoryMapEntry, DescriptorSize); >+ } >+ >+ *MemoryMapSize = (UINTN)NewMemoryMapEntry - >(UINTN)MemoryMap; >+ >+ return ; >+} >+ >+ >+/** >+ Remove exec permissions from all regions whose type is identified by >+ PcdDxeNxMemoryProtectionPolicy >+**/ >+STATIC >+VOID >+InitializeDxeNxMemoryProtectionPolicy ( >+ VOID >+ ) >+{ >+ UINTN MemoryMapSize; >+ UINTN MapKey; >+ UINTN DescriptorSize; >+ UINT32 DescriptorVersion; >+ EFI_MEMORY_DESCRIPTOR *MemoryMap; >+ EFI_MEMORY_DESCRIPTOR *MemoryMapEntry; >+ EFI_MEMORY_DESCRIPTOR *MemoryMapEnd; >+ EFI_STATUS Status; >+ UINT64 Attributes; >+ >+ // >+ // Get the EFI memory map. >+ // >+ MemoryMapSize = 0; >+ MemoryMap = NULL; >+ >+ Status = gBS->GetMemoryMap ( >+ &MemoryMapSize, >+ MemoryMap, >+ &MapKey, >+ &DescriptorSize, >+ &DescriptorVersion >+ ); >+ ASSERT (Status == EFI_BUFFER_TOO_SMALL); >+ do { >+ MemoryMap = (EFI_MEMORY_DESCRIPTOR *) AllocatePool >(MemoryMapSize); >+ ASSERT (MemoryMap != NULL); >+ Status = gBS->GetMemoryMap ( >+ &MemoryMapSize, >+ MemoryMap, >+ &MapKey, >+ &DescriptorSize, >+ &DescriptorVersion >+ ); >+ if (EFI_ERROR (Status)) { >+ FreePool (MemoryMap); >+ } >+ } while (Status == EFI_BUFFER_TOO_SMALL); >+ ASSERT_EFI_ERROR (Status); >+ >+ DEBUG((DEBUG_ERROR, "%a: removing exec permissions from memory >regions\n", >+ __FUNCTION__)); >+ >+ MergeMemoryMapForProtectionPolicy (MemoryMap, &MemoryMapSize, >DescriptorSize); >+ >+ MemoryMapEntry = MemoryMap; >+ MemoryMapEnd = (EFI_MEMORY_DESCRIPTOR *) ((UINT8 *) MemoryMap >+ MemoryMapSize); >+ while ((UINTN) MemoryMapEntry < (UINTN) MemoryMapEnd) { >+ >+ Attributes = GetPermissionAttributeForMemoryType (MemoryMapEntry- >>Type); >+ if (Attributes != 0) { >+ SetUefiImageMemoryAttributes ( >+ MemoryMapEntry->PhysicalStart, >+ EFI_PAGES_TO_SIZE (MemoryMapEntry->NumberOfPages), >+ Attributes); >+ } >+ MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, >DescriptorSize); >+ } >+ FreePool (MemoryMap); >+} >+ >+ >+/** > A notification for CPU_ARCH protocol. > > @param[in] Event Event whose notification function is being >invoked. >@@ -674,6 +884,17 @@ MemoryProtectionCpuArchProtocolNotify ( > return; > } > >+ // >+ // Apply the memory protection policy on non-BScode/RTcode regions. >+ // >+ if (PcdGet64 (PcdDxeNxMemoryProtectionPolicy) != 0) { >+ InitializeDxeNxMemoryProtectionPolicy (); >+ } >+ >+ if (mImageProtectionPolicy == 0) { >+ return; >+ } >+ > Status = gBS->LocateHandleBuffer ( > ByProtocol, > &gEfiLoadedImageProtocolGuid, >@@ -753,7 +974,7 @@ CoreInitializeMemoryProtection ( > > mImageProtectionPolicy = PcdGet32(PcdImageProtectionPolicy); > >- if (mImageProtectionPolicy != 0) { >+ if (mImageProtectionPolicy != 0 || PcdGet64 >(PcdDxeNxMemoryProtectionPolicy) != 0) { > Status = CoreCreateEvent ( > EVT_NOTIFY_SIGNAL, > TPL_CALLBACK, >@@ -775,3 +996,86 @@ CoreInitializeMemoryProtection ( > } > return ; > } >+ >+STATIC >+BOOLEAN >+IsInSmm ( >+ VOID >+ ) >+{ >+ BOOLEAN InSmm; >+ >+ InSmm = FALSE; >+ if (gSmmBase2 != NULL) { >+ gSmmBase2->InSmm (gSmmBase2, &InSmm); >+ } >+ return InSmm; >+} >+ >+/** >+ Manage memory permission attributes on a memory range, according to >the >+ configured DXE memory protection policy. >+ >+ @param OldType The old memory type of the range >+ @param NewType The new memory type of the range >+ @param Memory The base address of the range >+ @param Length The size of the range (in bytes) >+ >+ @return EFI_SUCCESS If we are executing in SMM mode. No permission >attributes >+ are updated in this case >+ @return EFI_SUCCESS If the the CPU arch protocol is not installed yet >+ @return EFI_SUCCESS If no DXE memory protection policy has been >configured >+ @return EFI_SUCCESS If OldType and NewType use the same permission >attributes >+ @return other Return value of gCpu->SetMemoryAttributes() >+ >+**/ >+EFI_STATUS >+EFIAPI >+ApplyMemoryProtectionPolicy ( >+ IN EFI_MEMORY_TYPE OldType, >+ IN EFI_MEMORY_TYPE NewType, >+ IN EFI_PHYSICAL_ADDRESS Memory, >+ IN UINT64 Length >+ ) >+{ >+ UINT64 OldAttributes; >+ UINT64 NewAttributes; >+ >+ // >+ // The policy configured in PcdDxeNxMemoryProtectionPolicy >+ // does not apply to allocations performed in SMM mode. >+ // >+ if (IsInSmm ()) { >+ return EFI_SUCCESS; >+ } >+ >+ // >+ // If the CPU arch protocol is not installed yet, we cannot manage memory >+ // permission attributes, and it is the job of the driver that installs this >+ // protocol to set the permissions on existing allocations. >+ // >+ if (gCpu == NULL) { >+ return EFI_SUCCESS; >+ } >+ >+ // >+ // Check if a DXE memory protection policy has been configured >+ // >+ if (PcdGet64 (PcdDxeNxMemoryProtectionPolicy) == 0) { >+ return EFI_SUCCESS; >+ } >+ >+ // >+ // Update the executable permissions according to the DXE memory >+ // protection policy, but only if the policy is different between >+ // the old and the new type. >+ // >+ OldAttributes = GetPermissionAttributeForMemoryType (OldType); >+ NewAttributes = GetPermissionAttributeForMemoryType (NewType); >+ >+ if (OldAttributes == NewAttributes) { >+ return EFI_SUCCESS; >+ } >+ >+ return gCpu->SetMemoryAttributes (gCpu, Memory, Length, >NewAttributes); >+} >-- >2.7.4 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
On 02/26/17 19:30, Ard Biesheuvel wrote: > This implements a DXE memory protection policy that ensure that regions > that don't require executable permissions are mapped with the non-exec > attribute set. > > First of all, it iterates over all entries in the UEFI memory map, and > removes executable permissions according to the configured DXE memory > protection policy, as recorded in PcdDxeMemoryProtectionPolicy. > > Secondly, it sets or clears the non-executable attribute when allocating > or freeing pages, both for page based or pool based allocations. > > Note that this complements the image protection facility, which applies > strict permissions to BootServicesCode/RuntimeServicesCode regions when > the section alignment allows it. The memory protection configured by this > patch operates on non-code regions only. > > Contributed-under: TianoCore Contribution Agreement 1.0 > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > MdeModulePkg/Core/Dxe/DxeMain.h | 24 ++ > MdeModulePkg/Core/Dxe/DxeMain.inf | 1 + > MdeModulePkg/Core/Dxe/Mem/Page.c | 4 + > MdeModulePkg/Core/Dxe/Mem/Pool.c | 7 + > MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 306 +++++++++++++++++++- > 5 files changed, 341 insertions(+), 1 deletion(-) [snip] > diff --git a/MdeModulePkg/Core/Dxe/DxeMain.inf b/MdeModulePkg/Core/Dxe/DxeMain.inf > index 371e91cb0d7e..30d5984f7c1f 100644 > --- a/MdeModulePkg/Core/Dxe/DxeMain.inf > +++ b/MdeModulePkg/Core/Dxe/DxeMain.inf > @@ -191,6 +191,7 @@ [Pcd] > gEfiMdeModulePkgTokenSpaceGuid.PcdMemoryProfileDriverPath ## CONSUMES > gEfiMdeModulePkgTokenSpaceGuid.PcdPropertiesTableEnable ## CONSUMES > gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy ## CONSUMES > + gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy ## CONSUMES > > # [Hob] > # RESOURCE_DESCRIPTOR ## CONSUMES The series doesn't build for me: .../MdeModulePkg/Core/Dxe/DxeMain.inf(194): error 3000: PCD [gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy] in [.../MdeModulePkg/Core/Dxe/DxeMain.inf] is not found in dependent packages: .../MdePkg/MdePkg.dec .../MdeModulePkg/MdeModulePkg.dec I think you forgot to add the .dec hunk to this patch. Thanks Laszlo _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
On 27 February 2017 at 09:56, Laszlo Ersek <lersek@redhat.com> wrote: > On 02/26/17 19:30, Ard Biesheuvel wrote: >> This implements a DXE memory protection policy that ensure that regions >> that don't require executable permissions are mapped with the non-exec >> attribute set. >> >> First of all, it iterates over all entries in the UEFI memory map, and >> removes executable permissions according to the configured DXE memory >> protection policy, as recorded in PcdDxeMemoryProtectionPolicy. >> >> Secondly, it sets or clears the non-executable attribute when allocating >> or freeing pages, both for page based or pool based allocations. >> >> Note that this complements the image protection facility, which applies >> strict permissions to BootServicesCode/RuntimeServicesCode regions when >> the section alignment allows it. The memory protection configured by this >> patch operates on non-code regions only. >> >> Contributed-under: TianoCore Contribution Agreement 1.0 >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> >> --- >> MdeModulePkg/Core/Dxe/DxeMain.h | 24 ++ >> MdeModulePkg/Core/Dxe/DxeMain.inf | 1 + >> MdeModulePkg/Core/Dxe/Mem/Page.c | 4 + >> MdeModulePkg/Core/Dxe/Mem/Pool.c | 7 + >> MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 306 +++++++++++++++++++- >> 5 files changed, 341 insertions(+), 1 deletion(-) > > [snip] > >> diff --git a/MdeModulePkg/Core/Dxe/DxeMain.inf b/MdeModulePkg/Core/Dxe/DxeMain.inf >> index 371e91cb0d7e..30d5984f7c1f 100644 >> --- a/MdeModulePkg/Core/Dxe/DxeMain.inf >> +++ b/MdeModulePkg/Core/Dxe/DxeMain.inf >> @@ -191,6 +191,7 @@ [Pcd] >> gEfiMdeModulePkgTokenSpaceGuid.PcdMemoryProfileDriverPath ## CONSUMES >> gEfiMdeModulePkgTokenSpaceGuid.PcdPropertiesTableEnable ## CONSUMES >> gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy ## CONSUMES >> + gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy ## CONSUMES >> >> # [Hob] >> # RESOURCE_DESCRIPTOR ## CONSUMES > > The series doesn't build for me: > > .../MdeModulePkg/Core/Dxe/DxeMain.inf(194): error 3000: PCD > [gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy] in > [.../MdeModulePkg/Core/Dxe/DxeMain.inf] is not found in dependent packages: > .../MdePkg/MdePkg.dec > .../MdeModulePkg/MdeModulePkg.dec > > I think you forgot to add the .dec hunk to this patch. > Apologies. I got the name wrong in the .dec, but I did update the branch I pushed to the link above with the only change being a fix for this. _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
diff --git a/MdeModulePkg/Core/Dxe/DxeMain.h b/MdeModulePkg/Core/Dxe/DxeMain.h index b14be9a74d8e..5668c1f2d648 100644 --- a/MdeModulePkg/Core/Dxe/DxeMain.h +++ b/MdeModulePkg/Core/Dxe/DxeMain.h @@ -2949,4 +2949,28 @@ MemoryProtectionExitBootServicesCallback ( VOID ); +/** + Manage memory permission attributes on a memory range, according to the + configured DXE memory protection policy. + + @param OldType The old memory type of the range + @param NewType The new memory type of the range + @param Memory The base address of the range + @param Length The size of the range (in bytes) + + @return EFI_SUCCESS If the the CPU arch protocol is not installed yet + @return EFI_SUCCESS If no DXE memory protection policy has been configured + @return EFI_SUCCESS If OldType and NewType use the same permission attributes + @return other Return value of gCpu->SetMemoryAttributes() + +**/ +EFI_STATUS +EFIAPI +ApplyMemoryProtectionPolicy ( + IN EFI_MEMORY_TYPE OldType, + IN EFI_MEMORY_TYPE NewType, + IN EFI_PHYSICAL_ADDRESS Memory, + IN UINT64 Length + ); + #endif diff --git a/MdeModulePkg/Core/Dxe/DxeMain.inf b/MdeModulePkg/Core/Dxe/DxeMain.inf index 371e91cb0d7e..30d5984f7c1f 100644 --- a/MdeModulePkg/Core/Dxe/DxeMain.inf +++ b/MdeModulePkg/Core/Dxe/DxeMain.inf @@ -191,6 +191,7 @@ [Pcd] gEfiMdeModulePkgTokenSpaceGuid.PcdMemoryProfileDriverPath ## CONSUMES gEfiMdeModulePkgTokenSpaceGuid.PcdPropertiesTableEnable ## CONSUMES gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy ## CONSUMES + gEfiMdeModulePkgTokenSpaceGuid.PcdDxeNxMemoryProtectionPolicy ## CONSUMES # [Hob] # RESOURCE_DESCRIPTOR ## CONSUMES diff --git a/MdeModulePkg/Core/Dxe/Mem/Page.c b/MdeModulePkg/Core/Dxe/Mem/Page.c index bda4f6397e91..86874906de58 100644 --- a/MdeModulePkg/Core/Dxe/Mem/Page.c +++ b/MdeModulePkg/Core/Dxe/Mem/Page.c @@ -1344,6 +1344,8 @@ CoreAllocatePages ( NULL ); InstallMemoryAttributesTableOnMemoryAllocation (MemoryType); + ApplyMemoryProtectionPolicy (EfiConventionalMemory, MemoryType, *Memory, + EFI_PAGES_TO_SIZE (NumberOfPages)); } return Status; } @@ -1460,6 +1462,8 @@ CoreFreePages ( NULL ); InstallMemoryAttributesTableOnMemoryAllocation (MemoryType); + ApplyMemoryProtectionPolicy (MemoryType, EfiConventionalMemory, Memory, + EFI_PAGES_TO_SIZE (NumberOfPages)); } return Status; } diff --git a/MdeModulePkg/Core/Dxe/Mem/Pool.c b/MdeModulePkg/Core/Dxe/Mem/Pool.c index 410615e0dee9..63b9983b88b5 100644 --- a/MdeModulePkg/Core/Dxe/Mem/Pool.c +++ b/MdeModulePkg/Core/Dxe/Mem/Pool.c @@ -305,6 +305,10 @@ CoreAllocatePoolPagesI ( Buffer = CoreAllocatePoolPages (PoolType, NoPages, Granularity); CoreReleaseMemoryLock (); + if (Buffer != NULL) { + ApplyMemoryProtectionPolicy (EfiConventionalMemory, PoolType, + (EFI_PHYSICAL_ADDRESS)(UINTN)Buffer, EFI_PAGES_TO_SIZE (NoPages)); + } return Buffer; } @@ -555,6 +559,9 @@ CoreFreePoolPagesI ( CoreAcquireMemoryLock (); CoreFreePoolPages (Memory, NoPages); CoreReleaseMemoryLock (); + + ApplyMemoryProtectionPolicy (PoolType, EfiConventionalMemory, + (EFI_PHYSICAL_ADDRESS)(UINTN)Memory, EFI_PAGES_TO_SIZE (NoPages)); } /** diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c index 46d88463d417..f2a69a3d0df9 100644 --- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c +++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c @@ -64,6 +64,12 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. #define DO_NOT_PROTECT 0x00000000 #define PROTECT_IF_ALIGNED_ELSE_ALLOW 0x00000001 +#define MEMORY_TYPE_OS_RESERVED_MIN 0x80000000 +#define MEMORY_TYPE_OEM_RESERVED_MIN 0x70000000 + +#define PREVIOUS_MEMORY_DESCRIPTOR(MemoryDescriptor, Size) \ + ((EFI_MEMORY_DESCRIPTOR *)((UINT8 *)(MemoryDescriptor) - (Size))) + UINT32 mImageProtectionPolicy; /** @@ -647,6 +653,210 @@ UnprotectUefiImage ( } /** + Return the EFI memory permission attribute associated with memory + type 'Type' under the configured DXE memory protection policy. +**/ +STATIC +UINT64 +GetPermissionAttributeForMemoryType ( + IN EFI_MEMORY_TYPE MemoryType + ) +{ + UINT64 TestBit; + + if ((UINT32) MemoryType >= MEMORY_TYPE_OS_RESERVED_MIN) { + TestBit = BIT63; + } else if ((UINT32) MemoryType >= MEMORY_TYPE_OEM_RESERVED_MIN) { + TestBit = BIT62; + } else { + TestBit = LShiftU64 (1, MemoryType); + } + + if ((PcdGet64 (PcdDxeNxMemoryProtectionPolicy) & TestBit) != 0) { + return EFI_MEMORY_XP; + } else { + return 0; + } +} + +/** + Sort memory map entries based upon PhysicalStart, from low to high. + + @param MemoryMap A pointer to the buffer in which firmware places + the current memory map. + @param MemoryMapSize Size, in bytes, of the MemoryMap buffer. + @param DescriptorSize Size, in bytes, of an individual EFI_MEMORY_DESCRIPTOR. +**/ +STATIC +VOID +SortMemoryMap ( + IN OUT EFI_MEMORY_DESCRIPTOR *MemoryMap, + IN UINTN MemoryMapSize, + IN UINTN DescriptorSize + ) +{ + EFI_MEMORY_DESCRIPTOR *MemoryMapEntry; + EFI_MEMORY_DESCRIPTOR *NextMemoryMapEntry; + EFI_MEMORY_DESCRIPTOR *MemoryMapEnd; + EFI_MEMORY_DESCRIPTOR TempMemoryMap; + + MemoryMapEntry = MemoryMap; + NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize); + MemoryMapEnd = (EFI_MEMORY_DESCRIPTOR *) ((UINT8 *) MemoryMap + MemoryMapSize); + while (MemoryMapEntry < MemoryMapEnd) { + while (NextMemoryMapEntry < MemoryMapEnd) { + if (MemoryMapEntry->PhysicalStart > NextMemoryMapEntry->PhysicalStart) { + CopyMem (&TempMemoryMap, MemoryMapEntry, sizeof(EFI_MEMORY_DESCRIPTOR)); + CopyMem (MemoryMapEntry, NextMemoryMapEntry, sizeof(EFI_MEMORY_DESCRIPTOR)); + CopyMem (NextMemoryMapEntry, &TempMemoryMap, sizeof(EFI_MEMORY_DESCRIPTOR)); + } + + NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (NextMemoryMapEntry, DescriptorSize); + } + + MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize); + NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize); + } +} + +/** + Merge adjacent memory map entries if they use the same memory protection policy + + @param[in, out] MemoryMap A pointer to the buffer in which firmware places + the current memory map. + @param[in, out] MemoryMapSize A pointer to the size, in bytes, of the + MemoryMap buffer. On input, this is the size of + the current memory map. On output, + it is the size of new memory map after merge. + @param[in] DescriptorSize Size, in bytes, of an individual EFI_MEMORY_DESCRIPTOR. +**/ +STATIC +VOID +MergeMemoryMapForProtectionPolicy ( + IN OUT EFI_MEMORY_DESCRIPTOR *MemoryMap, + IN OUT UINTN *MemoryMapSize, + IN UINTN DescriptorSize + ) +{ + EFI_MEMORY_DESCRIPTOR *MemoryMapEntry; + EFI_MEMORY_DESCRIPTOR *MemoryMapEnd; + UINT64 MemoryBlockLength; + EFI_MEMORY_DESCRIPTOR *NewMemoryMapEntry; + EFI_MEMORY_DESCRIPTOR *NextMemoryMapEntry; + UINT64 Attributes; + + SortMemoryMap (MemoryMap, *MemoryMapSize, DescriptorSize); + + MemoryMapEntry = MemoryMap; + NewMemoryMapEntry = MemoryMap; + MemoryMapEnd = (EFI_MEMORY_DESCRIPTOR *) ((UINT8 *) MemoryMap + *MemoryMapSize); + while ((UINTN)MemoryMapEntry < (UINTN)MemoryMapEnd) { + CopyMem (NewMemoryMapEntry, MemoryMapEntry, sizeof(EFI_MEMORY_DESCRIPTOR)); + NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize); + + do { + MemoryBlockLength = (UINT64) (EFI_PAGES_TO_SIZE((UINTN)MemoryMapEntry->NumberOfPages)); + Attributes = GetPermissionAttributeForMemoryType (MemoryMapEntry->Type); + + if (((UINTN)NextMemoryMapEntry < (UINTN)MemoryMapEnd) && + Attributes == GetPermissionAttributeForMemoryType (NextMemoryMapEntry->Type) && + ((MemoryMapEntry->PhysicalStart + MemoryBlockLength) == NextMemoryMapEntry->PhysicalStart)) { + MemoryMapEntry->NumberOfPages += NextMemoryMapEntry->NumberOfPages; + if (NewMemoryMapEntry != MemoryMapEntry) { + NewMemoryMapEntry->NumberOfPages += NextMemoryMapEntry->NumberOfPages; + } + + NextMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (NextMemoryMapEntry, DescriptorSize); + continue; + } else { + MemoryMapEntry = PREVIOUS_MEMORY_DESCRIPTOR (NextMemoryMapEntry, DescriptorSize); + break; + } + } while (TRUE); + + MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize); + NewMemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (NewMemoryMapEntry, DescriptorSize); + } + + *MemoryMapSize = (UINTN)NewMemoryMapEntry - (UINTN)MemoryMap; + + return ; +} + + +/** + Remove exec permissions from all regions whose type is identified by + PcdDxeNxMemoryProtectionPolicy +**/ +STATIC +VOID +InitializeDxeNxMemoryProtectionPolicy ( + VOID + ) +{ + UINTN MemoryMapSize; + UINTN MapKey; + UINTN DescriptorSize; + UINT32 DescriptorVersion; + EFI_MEMORY_DESCRIPTOR *MemoryMap; + EFI_MEMORY_DESCRIPTOR *MemoryMapEntry; + EFI_MEMORY_DESCRIPTOR *MemoryMapEnd; + EFI_STATUS Status; + UINT64 Attributes; + + // + // Get the EFI memory map. + // + MemoryMapSize = 0; + MemoryMap = NULL; + + Status = gBS->GetMemoryMap ( + &MemoryMapSize, + MemoryMap, + &MapKey, + &DescriptorSize, + &DescriptorVersion + ); + ASSERT (Status == EFI_BUFFER_TOO_SMALL); + do { + MemoryMap = (EFI_MEMORY_DESCRIPTOR *) AllocatePool (MemoryMapSize); + ASSERT (MemoryMap != NULL); + Status = gBS->GetMemoryMap ( + &MemoryMapSize, + MemoryMap, + &MapKey, + &DescriptorSize, + &DescriptorVersion + ); + if (EFI_ERROR (Status)) { + FreePool (MemoryMap); + } + } while (Status == EFI_BUFFER_TOO_SMALL); + ASSERT_EFI_ERROR (Status); + + DEBUG((DEBUG_ERROR, "%a: removing exec permissions from memory regions\n", + __FUNCTION__)); + + MergeMemoryMapForProtectionPolicy (MemoryMap, &MemoryMapSize, DescriptorSize); + + MemoryMapEntry = MemoryMap; + MemoryMapEnd = (EFI_MEMORY_DESCRIPTOR *) ((UINT8 *) MemoryMap + MemoryMapSize); + while ((UINTN) MemoryMapEntry < (UINTN) MemoryMapEnd) { + + Attributes = GetPermissionAttributeForMemoryType (MemoryMapEntry->Type); + if (Attributes != 0) { + SetUefiImageMemoryAttributes ( + MemoryMapEntry->PhysicalStart, + EFI_PAGES_TO_SIZE (MemoryMapEntry->NumberOfPages), + Attributes); + } + MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize); + } + FreePool (MemoryMap); +} + + +/** A notification for CPU_ARCH protocol. @param[in] Event Event whose notification function is being invoked. @@ -674,6 +884,17 @@ MemoryProtectionCpuArchProtocolNotify ( return; } + // + // Apply the memory protection policy on non-BScode/RTcode regions. + // + if (PcdGet64 (PcdDxeNxMemoryProtectionPolicy) != 0) { + InitializeDxeNxMemoryProtectionPolicy (); + } + + if (mImageProtectionPolicy == 0) { + return; + } + Status = gBS->LocateHandleBuffer ( ByProtocol, &gEfiLoadedImageProtocolGuid, @@ -753,7 +974,7 @@ CoreInitializeMemoryProtection ( mImageProtectionPolicy = PcdGet32(PcdImageProtectionPolicy); - if (mImageProtectionPolicy != 0) { + if (mImageProtectionPolicy != 0 || PcdGet64 (PcdDxeNxMemoryProtectionPolicy) != 0) { Status = CoreCreateEvent ( EVT_NOTIFY_SIGNAL, TPL_CALLBACK, @@ -775,3 +996,86 @@ CoreInitializeMemoryProtection ( } return ; } + +STATIC +BOOLEAN +IsInSmm ( + VOID + ) +{ + BOOLEAN InSmm; + + InSmm = FALSE; + if (gSmmBase2 != NULL) { + gSmmBase2->InSmm (gSmmBase2, &InSmm); + } + return InSmm; +} + +/** + Manage memory permission attributes on a memory range, according to the + configured DXE memory protection policy. + + @param OldType The old memory type of the range + @param NewType The new memory type of the range + @param Memory The base address of the range + @param Length The size of the range (in bytes) + + @return EFI_SUCCESS If we are executing in SMM mode. No permission attributes + are updated in this case + @return EFI_SUCCESS If the the CPU arch protocol is not installed yet + @return EFI_SUCCESS If no DXE memory protection policy has been configured + @return EFI_SUCCESS If OldType and NewType use the same permission attributes + @return other Return value of gCpu->SetMemoryAttributes() + +**/ +EFI_STATUS +EFIAPI +ApplyMemoryProtectionPolicy ( + IN EFI_MEMORY_TYPE OldType, + IN EFI_MEMORY_TYPE NewType, + IN EFI_PHYSICAL_ADDRESS Memory, + IN UINT64 Length + ) +{ + UINT64 OldAttributes; + UINT64 NewAttributes; + + // + // The policy configured in PcdDxeNxMemoryProtectionPolicy + // does not apply to allocations performed in SMM mode. + // + if (IsInSmm ()) { + return EFI_SUCCESS; + } + + // + // If the CPU arch protocol is not installed yet, we cannot manage memory + // permission attributes, and it is the job of the driver that installs this + // protocol to set the permissions on existing allocations. + // + if (gCpu == NULL) { + return EFI_SUCCESS; + } + + // + // Check if a DXE memory protection policy has been configured + // + if (PcdGet64 (PcdDxeNxMemoryProtectionPolicy) == 0) { + return EFI_SUCCESS; + } + + // + // Update the executable permissions according to the DXE memory + // protection policy, but only if the policy is different between + // the old and the new type. + // + OldAttributes = GetPermissionAttributeForMemoryType (OldType); + NewAttributes = GetPermissionAttributeForMemoryType (NewType); + + if (OldAttributes == NewAttributes) { + return EFI_SUCCESS; + } + + return gCpu->SetMemoryAttributes (gCpu, Memory, Length, NewAttributes); +}
This implements a DXE memory protection policy that ensure that regions that don't require executable permissions are mapped with the non-exec attribute set. First of all, it iterates over all entries in the UEFI memory map, and removes executable permissions according to the configured DXE memory protection policy, as recorded in PcdDxeMemoryProtectionPolicy. Secondly, it sets or clears the non-executable attribute when allocating or freeing pages, both for page based or pool based allocations. Note that this complements the image protection facility, which applies strict permissions to BootServicesCode/RuntimeServicesCode regions when the section alignment allows it. The memory protection configured by this patch operates on non-code regions only. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- MdeModulePkg/Core/Dxe/DxeMain.h | 24 ++ MdeModulePkg/Core/Dxe/DxeMain.inf | 1 + MdeModulePkg/Core/Dxe/Mem/Page.c | 4 + MdeModulePkg/Core/Dxe/Mem/Pool.c | 7 + MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 306 +++++++++++++++++++- 5 files changed, 341 insertions(+), 1 deletion(-) -- 2.7.4 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel