diff options
Diffstat (limited to 'src/platform-win32.cc')
| -rw-r--r-- | src/platform-win32.cc | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/src/platform-win32.cc b/src/platform-win32.cc index e2d123cd..af3e9b2f 100644 --- a/src/platform-win32.cc +++ b/src/platform-win32.cc @@ -838,12 +838,38 @@ size_t OS::AllocateAlignment() { void* OS::Allocate(const size_t requested, size_t* allocated, bool is_executable) { + // The address range used to randomize RWX allocations in OS::Allocate + // Try not to map pages into the default range that windows loads DLLs + // Note: This does not guarantee RWX regions will be within the + // range kAllocationRandomAddressMin to kAllocationRandomAddressMax +#ifdef V8_HOST_ARCH_64_BIT + static const intptr_t kAllocationRandomAddressMin = 0x0000000080000000; + static const intptr_t kAllocationRandomAddressMax = 0x000004FFFFFFFFFF; +#else + static const intptr_t kAllocationRandomAddressMin = 0x04000000; + static const intptr_t kAllocationRandomAddressMax = 0x4FFFFFFF; +#endif + // VirtualAlloc rounds allocated size to page size automatically. size_t msize = RoundUp(requested, static_cast<int>(GetPageSize())); + intptr_t address = NULL; // Windows XP SP2 allows Data Excution Prevention (DEP). int prot = is_executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE; - LPVOID mbase = VirtualAlloc(NULL, msize, MEM_COMMIT | MEM_RESERVE, prot); + + // For exectutable pages try and randomize the allocation address + if (prot == PAGE_EXECUTE_READWRITE && msize >= Page::kPageSize) { + address = (V8::Random() << kPageSizeBits) | kAllocationRandomAddressMin; + address &= kAllocationRandomAddressMax; + } + + LPVOID mbase = VirtualAlloc(reinterpret_cast<void *>(address), + msize, + MEM_COMMIT | MEM_RESERVE, + prot); + if (mbase == NULL && address != NULL) + mbase = VirtualAlloc(NULL, msize, MEM_COMMIT | MEM_RESERVE, prot); + if (mbase == NULL) { LOG(StringEvent("OS::Allocate", "VirtualAlloc failed")); return NULL; |