Samuel Huang | 6951a28 | 2018-04-30 22:47:52 +0000 | [diff] [blame] | 1 | // Copyright 2018 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 "components/zucchini/imposed_ensemble_matcher.h" |
| 6 | |
| 7 | #include <algorithm> |
| 8 | #include <sstream> |
| 9 | #include <utility> |
| 10 | |
| 11 | #include "base/bind.h" |
| 12 | #include "base/logging.h" |
| 13 | #include "components/zucchini/io_utils.h" |
| 14 | |
| 15 | namespace zucchini { |
| 16 | |
| 17 | /******** ImposedMatchParser ********/ |
| 18 | |
| 19 | ImposedMatchParser::ImposedMatchParser() = default; |
| 20 | |
| 21 | ImposedMatchParser::~ImposedMatchParser() = default; |
| 22 | |
| 23 | ImposedMatchParser::Status ImposedMatchParser::Parse( |
| 24 | std::string imposed_matches, |
| 25 | ConstBufferView old_image, |
| 26 | ConstBufferView new_image, |
| 27 | ElementDetector&& detector) { |
| 28 | CHECK(matches_.empty()); |
| 29 | CHECK(bad_matches_.empty()); |
| 30 | |
| 31 | // Parse |imposed_matches| and check bounds. |
| 32 | std::istringstream iss(std::move(imposed_matches)); |
| 33 | bool first = true; |
| 34 | iss.peek(); // Makes empty |iss| realize EOF is reached. |
| 35 | while (iss && !iss.eof()) { |
| 36 | // Eat delimiter. |
| 37 | if (first) { |
| 38 | first = false; |
| 39 | } else if (!(iss >> EatChar(','))) { |
| 40 | return kInvalidDelimiter; |
| 41 | } |
| 42 | // Extract parameters for one imposed match. |
| 43 | offset_t old_offset = 0U; |
| 44 | size_t old_size = 0U; |
| 45 | offset_t new_offset = 0U; |
| 46 | size_t new_size = 0U; |
| 47 | if (!(iss >> StrictUInt<offset_t>(old_offset) >> EatChar('+') >> |
| 48 | StrictUInt<size_t>(old_size) >> EatChar('=') >> |
| 49 | StrictUInt<offset_t>(new_offset) >> EatChar('+') >> |
| 50 | StrictUInt<size_t>(new_size))) { |
| 51 | return kParseError; |
| 52 | } |
| 53 | // Check bounds. |
| 54 | if (old_size == 0 || new_size == 0 || |
| 55 | !old_image.covers({old_offset, old_size}) || |
| 56 | !new_image.covers({new_offset, new_size})) { |
| 57 | return kOutOfBound; |
| 58 | } |
| 59 | matches_.push_back( |
| 60 | {{{old_offset, old_size}, kExeTypeUnknown}, // Assign type later. |
| 61 | {{new_offset, new_size}, kExeTypeUnknown}}); // Assign type later. |
| 62 | } |
| 63 | // Sort matches by "new" file offsets. This helps with overlap checks. |
| 64 | std::sort(matches_.begin(), matches_.end(), |
| 65 | [](const ElementMatch& match_a, const ElementMatch& match_b) { |
| 66 | return match_a.new_element.offset < match_b.new_element.offset; |
| 67 | }); |
| 68 | |
| 69 | // Check for overlaps in "new" file. |
| 70 | if (std::adjacent_find( |
| 71 | matches_.begin(), matches_.end(), |
| 72 | [](const ElementMatch& match1, const ElementMatch& match2) { |
| 73 | return match1.new_element.hi() > match2.new_element.lo(); |
| 74 | }) != matches_.end()) { |
| 75 | return kOverlapInNew; |
| 76 | } |
| 77 | |
| 78 | // Compute types and verify consistency. Remove identical matches and matches |
| 79 | // where any sub-image has an unknown type. |
| 80 | size_t write_idx = 0; |
| 81 | for (size_t read_idx = 0; read_idx < matches_.size(); ++read_idx) { |
| 82 | ConstBufferView old_sub_image( |
| 83 | old_image[matches_[read_idx].old_element.region()]); |
| 84 | ConstBufferView new_sub_image( |
| 85 | new_image[matches_[read_idx].new_element.region()]); |
| 86 | // Remove identical match. |
| 87 | if (old_sub_image.equals(new_sub_image)) { |
| 88 | ++num_identical_; |
| 89 | continue; |
| 90 | } |
| 91 | // Check executable types of sub-images. |
Anton Bikineev | 1a96551 | 2021-05-15 22:35:36 +0000 | [diff] [blame] | 92 | absl::optional<Element> old_element = detector.Run(old_sub_image); |
| 93 | absl::optional<Element> new_element = detector.Run(new_sub_image); |
Samuel Huang | 6951a28 | 2018-04-30 22:47:52 +0000 | [diff] [blame] | 94 | if (!old_element || !new_element) { |
| 95 | // Skip unknown types, including those mixed with known types. |
| 96 | bad_matches_.push_back(matches_[read_idx]); |
| 97 | continue; |
| 98 | } else if (old_element->exe_type != new_element->exe_type) { |
| 99 | // Error if types are known, but inconsistent. |
| 100 | return kTypeMismatch; |
| 101 | } |
| 102 | |
| 103 | // Keep match and remove gaps. |
| 104 | matches_[read_idx].old_element.exe_type = old_element->exe_type; |
| 105 | matches_[read_idx].new_element.exe_type = new_element->exe_type; |
| 106 | if (write_idx < read_idx) |
| 107 | matches_[write_idx] = matches_[read_idx]; |
| 108 | ++write_idx; |
| 109 | } |
| 110 | matches_.resize(write_idx); |
| 111 | return kSuccess; |
| 112 | } |
| 113 | |
| 114 | /******** ImposedEnsembleMatcher ********/ |
| 115 | |
| 116 | ImposedEnsembleMatcher::ImposedEnsembleMatcher( |
| 117 | const std::string& imposed_matches) |
| 118 | : imposed_matches_(imposed_matches) {} |
| 119 | |
| 120 | ImposedEnsembleMatcher::~ImposedEnsembleMatcher() = default; |
| 121 | |
| 122 | bool ImposedEnsembleMatcher::RunMatch(ConstBufferView old_image, |
| 123 | ConstBufferView new_image) { |
| 124 | DCHECK(matches_.empty()); |
| 125 | LOG(INFO) << "Start matching."; |
| 126 | ImposedMatchParser parser; |
| 127 | ImposedMatchParser::Status status = |
| 128 | parser.Parse(std::move(imposed_matches_), old_image, new_image, |
| 129 | base::BindRepeating(DetectElementFromDisassembler)); |
| 130 | // Print all warnings first. |
| 131 | for (const ElementMatch& bad_match : *parser.mutable_bad_matches()) |
| 132 | LOG(WARNING) << "Skipped match with unknown type: " << bad_match.ToString(); |
| 133 | if (status != ImposedMatchParser::kSuccess) { |
| 134 | LOG(ERROR) << "Imposed match failed with error code " << status << "."; |
| 135 | return false; |
| 136 | } |
| 137 | num_identical_ = parser.num_identical(); |
| 138 | matches_ = std::move(*parser.mutable_matches()); |
| 139 | Trim(); |
| 140 | return true; |
| 141 | } |
| 142 | |
| 143 | } // namespace zucchini |