| OLD | NEW |
| 1 // Copyright 2014 The Chromium Authors. All rights reserved. | 1 // Copyright 2014 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #include "base/allocator/partition_allocator/address_space_randomization.h" | 5 #include "base/allocator/partition_allocator/address_space_randomization.h" |
| 6 | 6 |
| 7 #include "base/allocator/partition_allocator/page_allocator.h" | 7 #include "base/allocator/partition_allocator/page_allocator.h" |
| 8 #include "base/synchronization/spin_lock.h" | 8 #include "base/synchronization/spin_lock.h" |
| 9 #include "build/build_config.h" | 9 #include "build/build_config.h" |
| 10 | 10 |
| (...skipping 62 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
| 73 uint32_t ret = ranvalInternal(x); | 73 uint32_t ret = ranvalInternal(x); |
| 74 return ret; | 74 return ret; |
| 75 } | 75 } |
| 76 | 76 |
| 77 static struct ranctx s_ranctx; | 77 static struct ranctx s_ranctx; |
| 78 | 78 |
| 79 } // namespace | 79 } // namespace |
| 80 | 80 |
| 81 // Calculates a random preferred mapping address. In calculating an address, we | 81 // Calculates a random preferred mapping address. In calculating an address, we |
| 82 // balance good ASLR against not fragmenting the address space too badly. | 82 // balance good ASLR against not fragmenting the address space too badly. |
| 83 void* getRandomPageBase() { | 83 void* GetRandomPageBase() { |
| 84 uintptr_t random; | 84 uintptr_t random; |
| 85 random = static_cast<uintptr_t>(ranval(&s_ranctx)); | 85 random = static_cast<uintptr_t>(ranval(&s_ranctx)); |
| 86 #if defined(ARCH_CPU_X86_64) | 86 #if defined(ARCH_CPU_X86_64) |
| 87 random <<= 32UL; | 87 random <<= 32UL; |
| 88 random |= static_cast<uintptr_t>(ranval(&s_ranctx)); | 88 random |= static_cast<uintptr_t>(ranval(&s_ranctx)); |
| 89 // This address mask gives a low likelihood of address space collisions. We | 89 // This address mask gives a low likelihood of address space collisions. We |
| 90 // handle the situation gracefully if there is a collision. | 90 // handle the situation gracefully if there is a collision. |
| 91 #if defined(OS_WIN) | 91 #if defined(OS_WIN) |
| 92 // 64-bit Windows has a bizarrely small 8TB user address space. Allocates in | 92 // 64-bit Windows has a bizarrely small 8TB user address space. Allocates in |
| 93 // the 1-5TB region. TODO(palmer): See if Windows >= 8.1 has the full 47 bits, | 93 // the 1-5TB region. TODO(palmer): See if Windows >= 8.1 has the full 47 bits, |
| (...skipping 27 matching lines...) Expand all Loading... |
| 121 // This is a good range on Windows, Linux and Mac. | 121 // This is a good range on Windows, Linux and Mac. |
| 122 // Allocates in the 0.5-1.5GB region. | 122 // Allocates in the 0.5-1.5GB region. |
| 123 random &= 0x3fffffff; | 123 random &= 0x3fffffff; |
| 124 random += 0x20000000; | 124 random += 0x20000000; |
| 125 #endif // defined(ARCH_CPU_X86_64) | 125 #endif // defined(ARCH_CPU_X86_64) |
| 126 random &= kPageAllocationGranularityBaseMask; | 126 random &= kPageAllocationGranularityBaseMask; |
| 127 return reinterpret_cast<void*>(random); | 127 return reinterpret_cast<void*>(random); |
| 128 } | 128 } |
| 129 | 129 |
| 130 } // namespace base | 130 } // namespace base |
| OLD | NEW |