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[Support] Support NetBSD PaX MPROTECT in sys::Memory.

Browse Source 
Removes AllocateRWX, setWritable and setExecutable from sys::Memory and
standardizes on allocateMappedMemory / protectMappedMemory. The
allocateMappedMemory method is updated to request full permissions for memory
blocks so that they can be marked executable later.

llvm-svn: 318464
This commit is contained in:
Lang Hames 2017-11-16 23:04:44 +00:00
parent 854a8743e8
commit afcb70d031
4 changed files with 30 additions and 256 deletions
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41
llvm/include/llvm/Support/Memory.h
View File

@ -109,51 +109,10 @@ namespace sys {
static std::error_code protectMappedMemory(const MemoryBlock &Block,
unsigned Flags);
/// This method allocates a block of Read/Write/Execute memory that is
/// suitable for executing dynamically generated code (e.g. JIT). An
/// attempt to allocate \p NumBytes bytes of virtual memory is made.
/// \p NearBlock may point to an existing allocation in which case
/// an attempt is made to allocate more memory near the existing block.
///
/// On success, this returns a non-null memory block, otherwise it returns
/// a null memory block and fills in *ErrMsg.
///
/// @brief Allocate Read/Write/Execute memory.
static MemoryBlock AllocateRWX(size_t NumBytes,
const MemoryBlock *NearBlock,
std::string *ErrMsg = nullptr);
/// This method releases a block of Read/Write/Execute memory that was
/// allocated with the AllocateRWX method. It should not be used to
/// release any memory block allocated any other way.
///
/// On success, this returns false, otherwise it returns true and fills
/// in *ErrMsg.
/// @brief Release Read/Write/Execute memory.
static bool ReleaseRWX(MemoryBlock &block, std::string *ErrMsg = nullptr);
/// InvalidateInstructionCache - Before the JIT can run a block of code
/// that has been emitted it must invalidate the instruction cache on some
/// platforms.
static void InvalidateInstructionCache(const void *Addr, size_t Len);
/// setExecutable - Before the JIT can run a block of code, it has to be
/// given read and executable privilege. Return true if it is already r-x
/// or the system is able to change its previlege.
static bool setExecutable(MemoryBlock &M, std::string *ErrMsg = nullptr);
/// setWritable - When adding to a block of code, the JIT may need
/// to mark a block of code as RW since the protections are on page
/// boundaries, and the JIT internal allocations are not page aligned.
static bool setWritable(MemoryBlock &M, std::string *ErrMsg = nullptr);
/// setRangeExecutable - Mark the page containing a range of addresses
/// as executable.
static bool setRangeExecutable(const void *Addr, size_t Size);
/// setRangeWritable - Mark the page containing a range of addresses
/// as writable.
static bool setRangeWritable(const void *Addr, size_t Size);
};
/// Owning version of MemoryBlock.

127
llvm/lib/Support/Unix/Memory.inc
View File

@ -102,6 +102,10 @@ Memory::allocateMappedMemory(size_t NumBytes,
int Protect = getPosixProtectionFlags(PFlags);
#if defined(__NetBSD__) && defined(PROT_MPROTECT)
Protect |= PROT_MPROTECT(PROT_READ | PROT_WRITE | PROT_EXEC);
#endif
// Use any near hint and the page size to set a page-aligned starting address
uintptr_t Start = NearBlock ? reinterpret_cast<uintptr_t>(NearBlock->base()) +
NearBlock->size() : 0;
@ -166,129 +170,6 @@ Memory::protectMappedMemory(const MemoryBlock &M, unsigned Flags) {
return std::error_code();
}
/// AllocateRWX - Allocate a slab of memory with read/write/execute
/// permissions. This is typically used for JIT applications where we want
/// to emit code to the memory then jump to it. Getting this type of memory
/// is very OS specific.
///
MemoryBlock
Memory::AllocateRWX(size_t NumBytes, const MemoryBlock* NearBlock,
std::string *ErrMsg) {
if (NumBytes == 0) return MemoryBlock();
static const size_t PageSize = Process::getPageSize();
size_t NumPages = (NumBytes+PageSize-1)/PageSize;
int fd = -1;
int flags = MAP_PRIVATE |
#ifdef MAP_ANONYMOUS
MAP_ANONYMOUS
#else
MAP_ANON
#endif
;
void* start = NearBlock ? (unsigned char*)NearBlock->base() +
NearBlock->size() : nullptr;
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_EXEC,
flags, fd, 0);
#elif defined(__NetBSD__) && defined(PROT_MPROTECT)
void *pa =
::mmap(start, PageSize * NumPages,
PROT_READ | PROT_WRITE | PROT_MPROTECT(PROT_EXEC), flags, fd, 0);
#else
void *pa = ::mmap(start, PageSize*NumPages, PROT_READ|PROT_WRITE|PROT_EXEC,
flags, fd, 0);
#endif
if (pa == MAP_FAILED) {
if (NearBlock) //Try again without a near hint
return AllocateRWX(NumBytes, nullptr);
MakeErrMsg(ErrMsg, "Can't allocate RWX Memory");
return MemoryBlock();
}
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)pa,
(vm_size_t)(PageSize*NumPages), 0,
VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
if (KERN_SUCCESS != kr) {
MakeErrMsg(ErrMsg, "vm_protect max RX failed");
return MemoryBlock();
}
kr = vm_protect(mach_task_self(), (vm_address_t)pa,
(vm_size_t)(PageSize*NumPages), 0,
VM_PROT_READ | VM_PROT_WRITE);
if (KERN_SUCCESS != kr) {
MakeErrMsg(ErrMsg, "vm_protect RW failed");
return MemoryBlock();
}
#endif
MemoryBlock result;
result.Address = pa;
result.Size = NumPages*PageSize;
return result;
}
bool Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) {
if (M.Address == nullptr || M.Size == 0) return false;
if (0 != ::munmap(M.Address, M.Size))
return MakeErrMsg(ErrMsg, "Can't release RWX Memory");
return false;
}
bool Memory::setWritable (MemoryBlock &M, std::string *ErrMsg) {
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
if (M.Address == 0 || M.Size == 0) return false;
Memory::InvalidateInstructionCache(M.Address, M.Size);
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address,
(vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_WRITE);
return KERN_SUCCESS == kr;
#else
return true;
#endif
}
bool Memory::setExecutable (MemoryBlock &M, std::string *ErrMsg) {
if (M.Address == nullptr || M.Size == 0) return false;
Memory::InvalidateInstructionCache(M.Address, M.Size);
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)M.Address,
(vm_size_t)M.Size, 0, VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
return KERN_SUCCESS == kr;
#else
return true;
#endif
}
bool Memory::setRangeWritable(const void *Addr, size_t Size) {
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)Addr,
(vm_size_t)Size, 0,
VM_PROT_READ | VM_PROT_WRITE);
return KERN_SUCCESS == kr;
#else
return true;
#endif
}
bool Memory::setRangeExecutable(const void *Addr, size_t Size) {
#if defined(__APPLE__) && (defined(__arm__) || defined(__arm64__))
kern_return_t kr = vm_protect(mach_task_self(), (vm_address_t)Addr,
(vm_size_t)Size, 0,
VM_PROT_READ | VM_PROT_EXECUTE | VM_PROT_COPY);
return KERN_SUCCESS == kr;
#else
return true;
#endif
}
/// InvalidateInstructionCache - Before the JIT can run a block of code
/// that has been emitted it must invalidate the instruction cache on some
/// platforms.

80
llvm/lib/Support/Windows/Memory.inc
View File

@ -160,85 +160,5 @@ void Memory::InvalidateInstructionCache(
FlushInstructionCache(GetCurrentProcess(), Addr, Len);
}
MemoryBlock Memory::AllocateRWX(size_t NumBytes,
const MemoryBlock *NearBlock,
std::string *ErrMsg) {
MemoryBlock MB;
std::error_code EC;
MB = allocateMappedMemory(NumBytes, NearBlock,
MF_READ|MF_WRITE|MF_EXEC, EC);
if (EC != std::error_code() && ErrMsg) {
MakeErrMsg(ErrMsg, EC.message());
}
return MB;
}
bool Memory::ReleaseRWX(MemoryBlock &M, std::string *ErrMsg) {
std::error_code EC = releaseMappedMemory(M);
if (EC == std::error_code())
return false;
MakeErrMsg(ErrMsg, EC.message());
return true;
}
static DWORD getProtection(const void *addr) {
MEMORY_BASIC_INFORMATION info;
if (sizeof(info) == ::VirtualQuery(addr, &info, sizeof(info))) {
return info.Protect;
}
return 0;
}
bool Memory::setWritable(MemoryBlock &M, std::string *ErrMsg) {
if (!setRangeWritable(M.Address, M.Size)) {
return MakeErrMsg(ErrMsg, "Cannot set memory to writeable");
}
return true;
}
bool Memory::setExecutable(MemoryBlock &M, std::string *ErrMsg) {
if (!setRangeExecutable(M.Address, M.Size)) {
return MakeErrMsg(ErrMsg, "Cannot set memory to executable");
}
return true;
}
bool Memory::setRangeWritable(const void *Addr, size_t Size) {
DWORD prot = getProtection(Addr);
if (!prot)
return false;
if (prot == PAGE_EXECUTE || prot == PAGE_EXECUTE_READ) {
prot = PAGE_EXECUTE_READWRITE;
} else if (prot == PAGE_NOACCESS || prot == PAGE_READONLY) {
prot = PAGE_READWRITE;
}
DWORD oldProt;
Memory::InvalidateInstructionCache(Addr, Size);
return ::VirtualProtect(const_cast<LPVOID>(Addr), Size, prot, &oldProt)
== TRUE;
}
bool Memory::setRangeExecutable(const void *Addr, size_t Size) {
DWORD prot = getProtection(Addr);
if (!prot)
return false;
if (prot == PAGE_NOACCESS) {
prot = PAGE_EXECUTE;
} else if (prot == PAGE_READONLY) {
prot = PAGE_EXECUTE_READ;
} else if (prot == PAGE_READWRITE) {
prot = PAGE_EXECUTE_READWRITE;
}
DWORD oldProt;
Memory::InvalidateInstructionCache(Addr, Size);
return ::VirtualProtect(const_cast<LPVOID>(Addr), Size, prot, &oldProt)
== TRUE;
}
} // namespace sys
} // namespace llvm

38
llvm/tools/llvm-rtdyld/llvm-rtdyld.cpp
View File

@ -178,10 +178,14 @@ public:
void deregisterEHFrames() override {}
void preallocateSlab(uint64_t Size) {
std::string Err;
sys::MemoryBlock MB = sys::Memory::AllocateRWX(Size, nullptr, &Err);
std::error_code EC;
sys::MemoryBlock MB =
sys::Memory::allocateMappedMemory(Size, nullptr,
sys::Memory::MF_READ |
sys::Memory::MF_WRITE,
EC);
if (!MB.base())
report_fatal_error("Can't allocate enough memory: " + Err);
report_fatal_error("Can't allocate enough memory: " + EC.message());
PreallocSlab = MB;
UsePreallocation = true;
@ -222,10 +226,14 @@ uint8_t *TrivialMemoryManager::allocateCodeSection(uintptr_t Size,
if (UsePreallocation)
return allocateFromSlab(Size, Alignment, true /* isCode */);
std::string Err;
sys::MemoryBlock MB = sys::Memory::AllocateRWX(Size, nullptr, &Err);
std::error_code EC;
sys::MemoryBlock MB =
sys::Memory::allocateMappedMemory(Size, nullptr,
sys::Memory::MF_READ |
sys::Memory::MF_WRITE,
EC);
if (!MB.base())
report_fatal_error("MemoryManager allocation failed: " + Err);
report_fatal_error("MemoryManager allocation failed: " + EC.message());
FunctionMemory.push_back(MB);
return (uint8_t*)MB.base();
}
@ -242,10 +250,14 @@ uint8_t *TrivialMemoryManager::allocateDataSection(uintptr_t Size,
if (UsePreallocation)
return allocateFromSlab(Size, Alignment, false /* isCode */);
std::string Err;
sys::MemoryBlock MB = sys::Memory::AllocateRWX(Size, nullptr, &Err);
std::error_code EC;
sys::MemoryBlock MB =
sys::Memory::allocateMappedMemory(Size, nullptr,
sys::Memory::MF_READ |
sys::Memory::MF_WRITE,
EC);
if (!MB.base())
report_fatal_error("MemoryManager allocation failed: " + Err);
report_fatal_error("MemoryManager allocation failed: " + EC.message());
DataMemory.push_back(MB);
return (uint8_t*)MB.base();
}
@ -453,9 +465,11 @@ static int executeInput() {
// Make sure the memory is executable.
// setExecutable will call InvalidateInstructionCache.
std::string ErrorStr;
if (!sys::Memory::setExecutable(FM, &ErrorStr))
ErrorAndExit("unable to mark function executable: '" + ErrorStr + "'");
if (auto EC = sys::Memory::protectMappedMemory(FM,
sys::Memory::MF_READ |
sys::Memory::MF_EXEC))
ErrorAndExit("unable to mark function executable: '" + EC.message() +
"'");
}
// Dispatch to _main().