Samuel Huang | 06f1ae9 | 2018-03-13 18:19:34 +0000 | [diff] [blame] | 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 | |
Etienne Pierre-doray | ae27d8e | 2018-07-24 15:42:33 +0000 | [diff] [blame] | 5 | #ifndef COMPONENTS_ZUCCHINI_RELOC_WIN32_H_ |
| 6 | #define COMPONENTS_ZUCCHINI_RELOC_WIN32_H_ |
Samuel Huang | 06f1ae9 | 2018-03-13 18:19:34 +0000 | [diff] [blame] | 7 | |
| 8 | #include <stddef.h> |
| 9 | #include <stdint.h> |
| 10 | |
| 11 | #include <vector> |
| 12 | |
Samuel Huang | 06f1ae9 | 2018-03-13 18:19:34 +0000 | [diff] [blame] | 13 | #include "components/zucchini/address_translator.h" |
| 14 | #include "components/zucchini/buffer_source.h" |
| 15 | #include "components/zucchini/buffer_view.h" |
| 16 | #include "components/zucchini/image_utils.h" |
Anton Bikineev | 1a96551 | 2021-05-15 22:35:36 +0000 | [diff] [blame] | 17 | #include "third_party/abseil-cpp/absl/types/optional.h" |
Samuel Huang | 06f1ae9 | 2018-03-13 18:19:34 +0000 | [diff] [blame] | 18 | |
| 19 | namespace zucchini { |
| 20 | |
| 21 | // Win32 PE relocation table stores a list of (type, RVA) pairs. The table is |
| 22 | // organized into "blocks" for RVAs with common high-order bits (12-31). Each |
| 23 | // block consists of a list (even length) of 2-byte "units". Each unit stores |
| 24 | // type (in bits 12-15) and low-order bits (0-11) of an RVA (in bits 0-11). In |
| 25 | // pseudo-struct: |
| 26 | // struct Block { |
| 27 | // uint32_t rva_hi; |
| 28 | // uint32_t block_size_in_bytes; // 8 + multiple of 4. |
| 29 | // struct { |
| 30 | // uint16_t rva_lo:12, type:4; // Little-endian. |
| 31 | // } units[(block_size_in_bytes - 8) / 2]; // Size must be even. |
| 32 | // } reloc_table[num_blocks]; // May have padding (type = 0). |
| 33 | |
| 34 | // Extracted Win32 reloc Unit data. |
| 35 | struct RelocUnitWin32 { |
| 36 | RelocUnitWin32(); |
| 37 | RelocUnitWin32(uint8_t type_in, offset_t location_in, rva_t target_rva_in); |
| 38 | friend bool operator==(const RelocUnitWin32& a, const RelocUnitWin32& b); |
| 39 | |
| 40 | uint8_t type; |
| 41 | offset_t location; |
| 42 | rva_t target_rva; |
| 43 | }; |
| 44 | |
| 45 | // A reader that parses Win32 PE relocation data and emits RelocUnitWin32 for |
| 46 | // each reloc unit that lies strictly inside |[lo, hi)|. |
| 47 | class RelocRvaReaderWin32 { |
| 48 | public: |
| 49 | enum : ptrdiff_t { kRelocUnitSize = sizeof(uint16_t) }; |
| 50 | |
| 51 | // Parses |image| at |reloc_region| to find beginning offsets of each reloc |
| 52 | // block. On success, writes the result to |reloc_block_offsets| and returns |
| 53 | // true. Otherwise leaves |reloc_block_offsets| in an undetermined state, and |
| 54 | // returns false. |
| 55 | static bool FindRelocBlocks(ConstBufferView image, |
| 56 | BufferRegion reloc_region, |
| 57 | std::vector<offset_t>* reloc_block_offsets); |
| 58 | |
| 59 | // |reloc_block_offsets| should be precomputed from FindRelBlocks(). |
| 60 | RelocRvaReaderWin32(ConstBufferView image, |
| 61 | BufferRegion reloc_region, |
| 62 | const std::vector<offset_t>& reloc_block_offsets, |
| 63 | offset_t lo, |
| 64 | offset_t hi); |
| 65 | RelocRvaReaderWin32(RelocRvaReaderWin32&&); |
| 66 | ~RelocRvaReaderWin32(); |
| 67 | |
Anton Bikineev | 1a96551 | 2021-05-15 22:35:36 +0000 | [diff] [blame] | 68 | // Successively visits and returns data for each reloc unit, or absl::nullopt |
Samuel Huang | 06f1ae9 | 2018-03-13 18:19:34 +0000 | [diff] [blame] | 69 | // when all reloc units are found. Encapsulates block transition details. |
Anton Bikineev | 1a96551 | 2021-05-15 22:35:36 +0000 | [diff] [blame] | 70 | absl::optional<RelocUnitWin32> GetNext(); |
Samuel Huang | 06f1ae9 | 2018-03-13 18:19:34 +0000 | [diff] [blame] | 71 | |
| 72 | private: |
| 73 | // Assuming that |block_begin| points to the beginning of a reloc block, loads |
| 74 | // |rva_hi_bits_| and assigns |cur_reloc_units_| as the region containing the |
| 75 | // associated units, potentially truncated by |end_it_|. Returns true if reloc |
| 76 | // data are available for read, and false otherwise. |
| 77 | bool LoadRelocBlock(ConstBufferView::const_iterator block_begin); |
| 78 | |
| 79 | const ConstBufferView image_; |
| 80 | |
| 81 | // End iterator. |
| 82 | ConstBufferView::const_iterator end_it_; |
| 83 | |
| 84 | // Unit data of the current reloc block. |
| 85 | BufferSource cur_reloc_units_; |
| 86 | |
| 87 | // High-order bits (12-31) for all relocs of the current reloc block. |
| 88 | rva_t rva_hi_bits_; |
| 89 | }; |
| 90 | |
| 91 | // A reader for Win32 reloc References, implemented as a filtering and |
| 92 | // translation adaptor of RelocRvaReaderWin32. |
| 93 | class RelocReaderWin32 : public ReferenceReader { |
| 94 | public: |
| 95 | // Takes ownership of |reloc_rva_reader|. |offset_bound| specifies the |
| 96 | // exclusive upper bound of reloc target offsets, taking account of widths of |
| 97 | // targets (which are abs32 References). |
| 98 | RelocReaderWin32(RelocRvaReaderWin32&& reloc_rva_reader, |
| 99 | uint16_t reloc_type, |
| 100 | offset_t offset_bound, |
| 101 | const AddressTranslator& translator); |
| 102 | ~RelocReaderWin32() override; |
| 103 | |
| 104 | // ReferenceReader: |
Anton Bikineev | 1a96551 | 2021-05-15 22:35:36 +0000 | [diff] [blame] | 105 | absl::optional<Reference> GetNext() override; |
Samuel Huang | 06f1ae9 | 2018-03-13 18:19:34 +0000 | [diff] [blame] | 106 | |
| 107 | private: |
| 108 | RelocRvaReaderWin32 reloc_rva_reader_; |
| 109 | const uint16_t reloc_type_; // uint16_t to simplify shifting (<< 12). |
| 110 | const offset_t offset_bound_; |
| 111 | AddressTranslator::RvaToOffsetCache entry_rva_to_offset_; |
| 112 | }; |
| 113 | |
| 114 | // A writer for Win32 reloc References. This is simpler than the reader since: |
| 115 | // - No iteration is required. |
| 116 | // - High-order bits of reloc target RVAs are assumed to be handled elsewhere, |
| 117 | // so only low-order bits need to be written. |
| 118 | class RelocWriterWin32 : public ReferenceWriter { |
| 119 | public: |
| 120 | RelocWriterWin32(uint16_t reloc_type, |
| 121 | MutableBufferView image, |
| 122 | BufferRegion reloc_region, |
| 123 | const std::vector<offset_t>& reloc_block_offsets, |
| 124 | const AddressTranslator& translator); |
| 125 | ~RelocWriterWin32() override; |
| 126 | |
| 127 | // ReferenceWriter: |
| 128 | void PutNext(Reference ref) override; |
| 129 | |
| 130 | private: |
| 131 | const uint16_t reloc_type_; |
| 132 | MutableBufferView image_; |
| 133 | BufferRegion reloc_region_; |
| 134 | const std::vector<offset_t>& reloc_block_offsets_; |
| 135 | AddressTranslator::OffsetToRvaCache target_offset_to_rva_; |
| 136 | }; |
| 137 | |
| 138 | } // namespace zucchini |
| 139 | |
Etienne Pierre-doray | ae27d8e | 2018-07-24 15:42:33 +0000 | [diff] [blame] | 140 | #endif // COMPONENTS_ZUCCHINI_RELOC_WIN32_H_ |