1 // Copyright (c) 2010 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 #ifndef CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_STORE_H_ 6 #define CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_STORE_H_ 7 #pragma once 8 9 #include <set> 10 #include <vector> 11 12 #include "base/basictypes.h" 13 #include "base/callback.h" 14 #include "base/hash_tables.h" 15 #include "base/task.h" 16 #include "base/time.h" 17 #include "chrome/browser/safe_browsing/safe_browsing_util.h" 18 19 class FilePath; 20 21 // SafeBrowsingStore provides a storage abstraction for the 22 // safe-browsing data used to build the bloom filter. The items 23 // stored are: 24 // The set of add and sub chunks seen. 25 // List of SBAddPrefix (chunk_id and SBPrefix). 26 // List of SBSubPrefix (chunk_id and the target SBAddPrefix). 27 // List of SBAddFullHash (SBAddPrefix, time received and an SBFullHash). 28 // List of SBSubFullHash (chunk_id, target SBAddPrefix, and an SBFullHash). 29 // 30 // The store is geared towards updating the data, not runtime access 31 // to the data (that is handled by SafeBrowsingDatabase). Updates are 32 // handled similar to a SQL transaction cycle, with the new data being 33 // returned from FinishUpdate() (the COMMIT). Data is not persistent 34 // until FinishUpdate() returns successfully. 35 // 36 // FinishUpdate() also handles dropping items who's chunk has been 37 // deleted, and netting out the add/sub lists (when a sub matches an 38 // add, both are dropped). 39 40 // GetAddChunkId(), GetAddPrefix() and GetFullHash() are exposed so 41 // that these items can be generically compared with each other by 42 // SBAddPrefixLess() and SBAddPrefixHashLess(). 43 44 struct SBAddPrefix { 45 int32 chunk_id; 46 SBPrefix prefix; 47 48 SBAddPrefix(int32 id, SBPrefix p) : chunk_id(id), prefix(p) {} 49 SBAddPrefix() : chunk_id(), prefix() {} 50 51 int32 GetAddChunkId() const { return chunk_id; } 52 SBPrefix GetAddPrefix() const { return prefix; } 53 }; 54 55 struct SBSubPrefix { 56 int32 chunk_id; 57 int32 add_chunk_id; 58 SBPrefix add_prefix; 59 60 SBSubPrefix(int32 id, int32 add_id, int prefix) 61 : chunk_id(id), add_chunk_id(add_id), add_prefix(prefix) {} 62 SBSubPrefix() : chunk_id(), add_chunk_id(), add_prefix() {} 63 64 int32 GetAddChunkId() const { return add_chunk_id; } 65 SBPrefix GetAddPrefix() const { return add_prefix; } 66 }; 67 68 struct SBAddFullHash { 69 int32 chunk_id; 70 int32 received; 71 SBFullHash full_hash; 72 73 SBAddFullHash(int32 id, base::Time r, const SBFullHash& h) 74 : chunk_id(id), 75 received(static_cast<int32>(r.ToTimeT())), 76 full_hash(h) { 77 } 78 79 // Provided for ReadAddHashes() implementations, which already have 80 // an int32 for the time. 81 SBAddFullHash(int32 id, int32 r, const SBFullHash& h) 82 : chunk_id(id), received(r), full_hash(h) {} 83 84 SBAddFullHash() : chunk_id(), received(), full_hash() {} 85 86 int32 GetAddChunkId() const { return chunk_id; } 87 SBPrefix GetAddPrefix() const { return full_hash.prefix; } 88 }; 89 90 struct SBSubFullHash { 91 int32 chunk_id; 92 int32 add_chunk_id; 93 SBFullHash full_hash; 94 95 SBSubFullHash(int32 id, int32 add_id, const SBFullHash& h) 96 : chunk_id(id), add_chunk_id(add_id), full_hash(h) {} 97 SBSubFullHash() : chunk_id(), add_chunk_id(), full_hash() {} 98 99 int32 GetAddChunkId() const { return add_chunk_id; } 100 SBPrefix GetAddPrefix() const { return full_hash.prefix; } 101 }; 102 103 // Determine less-than based on add chunk and prefix. 104 template <class T, class U> 105 bool SBAddPrefixLess(const T& a, const U& b) { 106 if (a.GetAddChunkId() != b.GetAddChunkId()) 107 return a.GetAddChunkId() < b.GetAddChunkId(); 108 109 return a.GetAddPrefix() < b.GetAddPrefix(); 110 } 111 112 // Determine less-than based on add chunk, prefix, and full hash. 113 // Prefix can compare differently than hash due to byte ordering, 114 // so it must take precedence. 115 template <class T, class U> 116 bool SBAddPrefixHashLess(const T& a, const U& b) { 117 if (SBAddPrefixLess(a, b)) 118 return true; 119 120 if (SBAddPrefixLess(b, a)) 121 return false; 122 123 return memcmp(a.full_hash.full_hash, b.full_hash.full_hash, 124 sizeof(a.full_hash.full_hash)) < 0; 125 } 126 127 // Process the lists for subs which knock out adds. For any item in 128 // |sub_prefixes| which has a match in |add_prefixes|, knock out the 129 // matched items from all vectors. Additionally remove items from 130 // deleted chunks. 131 // 132 // TODO(shess): Since the prefixes are uniformly-distributed hashes, 133 // there aren't many ways to organize the inputs for efficient 134 // processing. For this reason, the vectors are sorted and processed 135 // in parallel. At this time this code does the sorting internally, 136 // but it might make sense to make sorting an API requirement so that 137 // the storage can optimize for it. 138 // 139 // TODO(shess): The original code did not process |sub_full_hashes| 140 // for matches in |add_full_hashes|, so this code doesn't, either. I 141 // think this is probably a bug. 142 void SBProcessSubs(std::vector<SBAddPrefix>* add_prefixes, 143 std::vector<SBSubPrefix>* sub_prefixes, 144 std::vector<SBAddFullHash>* add_full_hashes, 145 std::vector<SBSubFullHash>* sub_full_hashes, 146 const base::hash_set<int32>& add_chunks_deleted, 147 const base::hash_set<int32>& sub_chunks_deleted); 148 149 // Records a histogram of the number of items in |prefix_misses| which 150 // are not in |add_prefixes|. 151 void SBCheckPrefixMisses(const std::vector<SBAddPrefix>& add_prefixes, 152 const std::set<SBPrefix>& prefix_misses); 153 154 // TODO(shess): This uses int32 rather than int because it's writing 155 // specifically-sized items to files. SBPrefix should likewise be 156 // explicitly sized. 157 158 // Abstract interface for storing data. 159 class SafeBrowsingStore { 160 public: 161 SafeBrowsingStore() {} 162 virtual ~SafeBrowsingStore() {} 163 164 // Sets up the information for later use, but does not necessarily 165 // check whether the underlying file exists, or is valid. If 166 // |curruption_callback| is non-NULL it will be called if corruption 167 // is detected, which could happen as part of any call other than 168 // Delete(). The appropriate action is to use Delete() to clear the 169 // store. 170 virtual void Init(const FilePath& filename, 171 Callback0::Type* corruption_callback) = 0; 172 173 // Deletes the files which back the store, returning true if 174 // successful. 175 virtual bool Delete() = 0; 176 177 // Get all Add prefixes out from the store. 178 virtual bool GetAddPrefixes(std::vector<SBAddPrefix>* add_prefixes) = 0; 179 180 // Get all add full-length hashes. 181 virtual bool GetAddFullHashes( 182 std::vector<SBAddFullHash>* add_full_hashes) = 0; 183 184 // Start an update. None of the following methods should be called 185 // unless this returns true. If this returns true, the update 186 // should be terminated by FinishUpdate() or CancelUpdate(). 187 virtual bool BeginUpdate() = 0; 188 189 // Start a chunk of data. None of the methods through FinishChunk() 190 // should be called unless this returns true. 191 // TODO(shess): Would it make sense for this to accept |chunk_id|? 192 // Possibly not, because of possible confusion between sub_chunk_id 193 // and add_chunk_id. 194 virtual bool BeginChunk() = 0; 195 196 virtual bool WriteAddPrefix(int32 chunk_id, SBPrefix prefix) = 0; 197 virtual bool WriteAddHash(int32 chunk_id, 198 base::Time receive_time, 199 const SBFullHash& full_hash) = 0; 200 virtual bool WriteSubPrefix(int32 chunk_id, 201 int32 add_chunk_id, SBPrefix prefix) = 0; 202 virtual bool WriteSubHash(int32 chunk_id, int32 add_chunk_id, 203 const SBFullHash& full_hash) = 0; 204 205 // Collect the chunk data and preferrably store it on disk to 206 // release memory. Shoul not modify the data in-place. 207 virtual bool FinishChunk() = 0; 208 209 // Track the chunks which have been seen. 210 virtual void SetAddChunk(int32 chunk_id) = 0; 211 virtual bool CheckAddChunk(int32 chunk_id) = 0; 212 virtual void GetAddChunks(std::vector<int32>* out) = 0; 213 virtual void SetSubChunk(int32 chunk_id) = 0; 214 virtual bool CheckSubChunk(int32 chunk_id) = 0; 215 virtual void GetSubChunks(std::vector<int32>* out) = 0; 216 217 // Delete the indicated chunk_id. The chunk will continue to be 218 // visible until the end of the transaction. 219 virtual void DeleteAddChunk(int32 chunk_id) = 0; 220 virtual void DeleteSubChunk(int32 chunk_id) = 0; 221 222 // Pass the collected chunks through SBPRocessSubs() and commit to 223 // permanent storage. The resulting add prefixes and hashes will be 224 // stored in |add_prefixes_result| and |add_full_hashes_result|. 225 // |pending_adds| is the set of full hashes which have been received 226 // since the previous update, and is provided as a convenience 227 // (could be written via WriteAddHash(), but that would flush the 228 // chunk to disk). |prefix_misses| is the set of prefixes where the 229 // |GetHash()| request returned no full hashes, used for diagnostic 230 // purposes. 231 virtual bool FinishUpdate( 232 const std::vector<SBAddFullHash>& pending_adds, 233 const std::set<SBPrefix>& prefix_misses, 234 std::vector<SBAddPrefix>* add_prefixes_result, 235 std::vector<SBAddFullHash>* add_full_hashes_result) = 0; 236 237 // Cancel the update in process and remove any temporary disk 238 // storage, leaving the original data unmodified. 239 virtual bool CancelUpdate() = 0; 240 241 private: 242 DISALLOW_COPY_AND_ASSIGN(SafeBrowsingStore); 243 }; 244 245 #endif // CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_STORE_H_ 246