1 // Copyright 2017 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "base/memory/protected_memory.h" 6 7 #include <stdint.h> 8 #include <sys/mman.h> 9 #include <unistd.h> 10 11 #if defined(OS_LINUX) 12 #include <sys/resource.h> 13 #endif // defined(OS_LINUX) 14 15 #if defined(OS_MACOSX) && !defined(OS_IOS) 16 #include <mach/mach.h> 17 #include <mach/mach_vm.h> 18 #endif // defined(OS_MACOSX) && !defined(OS_IOS) 19 20 #include "base/posix/eintr_wrapper.h" 21 #include "base/process/process_metrics.h" 22 #include "base/synchronization/lock.h" 23 #include "build/build_config.h" 24 25 namespace base { 26 27 namespace { 28 29 bool SetMemory(void* start, void* end, int prot) { 30 DCHECK(end > start); 31 const uintptr_t page_mask = ~(base::GetPageSize() - 1); 32 const uintptr_t page_start = reinterpret_cast<uintptr_t>(start) & page_mask; 33 return mprotect(reinterpret_cast<void*>(page_start), 34 reinterpret_cast<uintptr_t>(end) - page_start, prot) == 0; 35 } 36 37 } // namespace 38 39 bool AutoWritableMemory::SetMemoryReadWrite(void* start, void* end) { 40 return SetMemory(start, end, PROT_READ | PROT_WRITE); 41 } 42 43 bool AutoWritableMemory::SetMemoryReadOnly(void* start, void* end) { 44 return SetMemory(start, end, PROT_READ); 45 } 46 47 #if defined(OS_LINUX) 48 void AssertMemoryIsReadOnly(const void* ptr) { 49 #if DCHECK_IS_ON() 50 const uintptr_t page_mask = ~(base::GetPageSize() - 1); 51 const uintptr_t page_start = reinterpret_cast<uintptr_t>(ptr) & page_mask; 52 53 // Note: We've casted away const here, which should not be meaningful since 54 // if the memory is written to we will abort immediately. 55 int result = 56 getrlimit(RLIMIT_NPROC, reinterpret_cast<struct rlimit*>(page_start)); 57 DCHECK_EQ(result, -1); 58 DCHECK_EQ(errno, EFAULT); 59 #endif // DCHECK_IS_ON() 60 } 61 #elif defined(OS_MACOSX) && !defined(OS_IOS) 62 void AssertMemoryIsReadOnly(const void* ptr) { 63 #if DCHECK_IS_ON() 64 mach_port_t object_name; 65 vm_region_basic_info_64 region_info; 66 mach_vm_size_t size = 1; 67 mach_msg_type_number_t count = VM_REGION_BASIC_INFO_COUNT_64; 68 69 kern_return_t kr = mach_vm_region( 70 mach_task_self(), reinterpret_cast<mach_vm_address_t*>(&ptr), &size, 71 VM_REGION_BASIC_INFO_64, reinterpret_cast<vm_region_info_t>(®ion_info), 72 &count, &object_name); 73 DCHECK_EQ(kr, KERN_SUCCESS); 74 DCHECK_EQ(region_info.protection, VM_PROT_READ); 75 #endif // DCHECK_IS_ON() 76 } 77 #endif // defined(OS_LINUX) || (defined(OS_MACOSX) && !defined(OS_IOS)) 78 79 } // namespace base 80