From 7fef06af4ec100f3f8856e3fa08ef067a9fd40d2 Mon Sep 17 00:00:00 2001 From: Jian J Wang Date: Wed, 14 Mar 2018 16:28:34 +0800 Subject: [PATCH] MdeModulePkg/Core: allow HeapGuard even before CpuArchProtocol installed Due to the fact that HeapGuard needs CpuArchProtocol to update page attributes, the feature is normally enabled after CpuArchProtocol is installed. Since there're some drivers are loaded before CpuArchProtocl, they cannot make use HeapGuard feature to detect potential issues. This patch fixes above situation by updating the DXE core to skip the NULL check against global gCpu in the IsMemoryTypeToGuard(), and adding NULL check against gCpu in SetGuardPage() and UnsetGuardPage() to make sure that they can be called but do nothing. This will allow HeapGuard to record all guarded memory without setting the related Guard pages to not- present. Once the CpuArchProtocol is installed, a protocol notify will be called to complete the work of setting Guard pages to not-present. Please note that above changes will cause a #PF in GCD code during cleanup of map entries, which is initiated by CpuDxe driver to update real mtrr and paging attributes back to GCD. During that time, CpuDxe doesn't allow GCD to update memory attributes and then any Guard page cannot be unset. As a result, this will prevent Guarded memory from freeing during memory map cleanup. The solution is to avoid allocating guarded memory as memory map entries in GCD code. It's done by setting global mOnGuarding to TRUE before memory allocation and setting it back to FALSE afterwards in GCD function CoreAllocateGcdMapEntry(). Cc: Star Zeng Cc: Eric Dong Cc: Jiewen Yao Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Jian J Wang Reviewed-by: Ruiyu Ni --- MdeModulePkg/Core/Dxe/Gcd/Gcd.c | 10 ++ MdeModulePkg/Core/Dxe/Mem/HeapGuard.c | 132 +++++++++++++++++- MdeModulePkg/Core/Dxe/Mem/HeapGuard.h | 8 ++ MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 5 + 4 files changed, 154 insertions(+), 1 deletion(-) diff --git a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c index 8fbc3d282c..77f4adb4bc 100644 --- a/MdeModulePkg/Core/Dxe/Gcd/Gcd.c +++ b/MdeModulePkg/Core/Dxe/Gcd/Gcd.c @@ -16,6 +16,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. #include "DxeMain.h" #include "Gcd.h" +#include "Mem/HeapGuard.h" #define MINIMUM_INITIAL_MEMORY_SIZE 0x10000 @@ -391,12 +392,21 @@ CoreAllocateGcdMapEntry ( IN OUT EFI_GCD_MAP_ENTRY **BottomEntry ) { + // + // Set to mOnGuarding to TRUE before memory allocation. This will make sure + // that the entry memory is not "guarded" by HeapGuard. Otherwise it might + // cause problem when it's freed (if HeapGuard is enabled). + // + mOnGuarding = TRUE; *TopEntry = AllocateZeroPool (sizeof (EFI_GCD_MAP_ENTRY)); + mOnGuarding = FALSE; if (*TopEntry == NULL) { return EFI_OUT_OF_RESOURCES; } + mOnGuarding = TRUE; *BottomEntry = AllocateZeroPool (sizeof (EFI_GCD_MAP_ENTRY)); + mOnGuarding = FALSE; if (*BottomEntry == NULL) { CoreFreePool (*TopEntry); return EFI_OUT_OF_RESOURCES; diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c index ac043b5d9b..f6068c459c 100644 --- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c +++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c @@ -576,6 +576,10 @@ SetGuardPage ( IN EFI_PHYSICAL_ADDRESS BaseAddress ) { + if (gCpu == NULL) { + return; + } + // // Set flag to make sure allocating memory without GUARD for page table // operation; otherwise infinite loops could be caused. @@ -606,6 +610,10 @@ UnsetGuardPage ( { UINT64 Attributes; + if (gCpu == NULL) { + return; + } + // // Once the Guard page is unset, it will be freed back to memory pool. NX // memory protection must be restored for this page if NX is enabled for free @@ -652,7 +660,7 @@ IsMemoryTypeToGuard ( UINT64 ConfigBit; BOOLEAN InSmm; - if (gCpu == NULL || AllocateType == AllocateAddress) { + if (AllocateType == AllocateAddress) { return FALSE; } @@ -1164,6 +1172,128 @@ CoreConvertPagesWithGuard ( return CoreConvertPages (Start, NumberOfPages, NewType); } +/** + Set all Guard pages which cannot be set before CPU Arch Protocol installed. +**/ +VOID +SetAllGuardPages ( + VOID + ) +{ + UINTN Entries[GUARDED_HEAP_MAP_TABLE_DEPTH]; + UINTN Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH]; + UINTN Indices[GUARDED_HEAP_MAP_TABLE_DEPTH]; + UINT64 Tables[GUARDED_HEAP_MAP_TABLE_DEPTH]; + UINT64 Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH]; + UINT64 TableEntry; + UINT64 Address; + UINT64 GuardPage; + INTN Level; + UINTN Index; + BOOLEAN OnGuarding; + + if (mGuardedMemoryMap == 0 || + mMapLevel == 0 || + mMapLevel > GUARDED_HEAP_MAP_TABLE_DEPTH) { + return; + } + + CopyMem (Entries, mLevelMask, sizeof (Entries)); + CopyMem (Shifts, mLevelShift, sizeof (Shifts)); + + SetMem (Tables, sizeof(Tables), 0); + SetMem (Addresses, sizeof(Addresses), 0); + SetMem (Indices, sizeof(Indices), 0); + + Level = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel; + Tables[Level] = mGuardedMemoryMap; + Address = 0; + OnGuarding = FALSE; + + DEBUG_CODE ( + DumpGuardedMemoryBitmap (); + ); + + while (TRUE) { + if (Indices[Level] > Entries[Level]) { + Tables[Level] = 0; + Level -= 1; + } else { + + TableEntry = ((UINT64 *)(UINTN)(Tables[Level]))[Indices[Level]]; + Address = Addresses[Level]; + + if (TableEntry == 0) { + + OnGuarding = FALSE; + + } else if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) { + + Level += 1; + Tables[Level] = TableEntry; + Addresses[Level] = Address; + Indices[Level] = 0; + + continue; + + } else { + + Index = 0; + while (Index < GUARDED_HEAP_MAP_ENTRY_BITS) { + if ((TableEntry & 1) == 1) { + if (OnGuarding) { + GuardPage = 0; + } else { + GuardPage = Address - EFI_PAGE_SIZE; + } + OnGuarding = TRUE; + } else { + if (OnGuarding) { + GuardPage = Address; + } else { + GuardPage = 0; + } + OnGuarding = FALSE; + } + + if (GuardPage != 0) { + SetGuardPage (GuardPage); + } + + if (TableEntry == 0) { + break; + } + + TableEntry = RShiftU64 (TableEntry, 1); + Address += EFI_PAGE_SIZE; + Index += 1; + } + } + } + + if (Level < (GUARDED_HEAP_MAP_TABLE_DEPTH - (INTN)mMapLevel)) { + break; + } + + Indices[Level] += 1; + Address = (Level == 0) ? 0 : Addresses[Level - 1]; + Addresses[Level] = Address | LShiftU64(Indices[Level], Shifts[Level]); + + } +} + +/** + Notify function used to set all Guard pages before CPU Arch Protocol installed. +**/ +VOID +HeapGuardCpuArchProtocolNotify ( + VOID + ) +{ + ASSERT (gCpu != NULL); + SetAllGuardPages (); +} + /** Helper function to convert a UINT64 value in binary to a string. diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h index 7208ab1437..8c34692439 100644 --- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h +++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h @@ -399,6 +399,14 @@ IsHeapGuardEnabled ( VOID ); +/** + Notify function used to set all Guard pages after CPU Arch Protocol installed. +**/ +VOID +HeapGuardCpuArchProtocolNotify ( + VOID + ); + extern BOOLEAN mOnGuarding; #endif diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c index 407aece807..2f7e490af1 100644 --- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c +++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c @@ -1001,6 +1001,11 @@ MemoryProtectionCpuArchProtocolNotify ( InitializeDxeNxMemoryProtectionPolicy (); } + // + // Call notify function meant for Heap Guard. + // + HeapGuardCpuArchProtocolNotify (); + if (mImageProtectionPolicy == 0) { return; } -- 2.39.2