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 19class 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 44struct 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 55struct 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 68struct 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 90struct 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. 104template <class T, class U> 105bool 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. 115template <class T, class U> 116bool 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. 142void 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|. 151void 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. 159class 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