1 // Copyright (c) 2012 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.
5 #ifndef CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_STORE_H_
6 #define CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_STORE_H_
11 #include "base/basictypes.h"
12 #include "base/callback_forward.h"
13 #include "base/containers/hash_tables.h"
14 #include "base/time/time.h"
15 #include "chrome/browser/safe_browsing/safe_browsing_util.h"
21 // SafeBrowsingStore provides a storage abstraction for the
22 // safe-browsing data used to build the bloom filter. The items
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).
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.
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).
40 // GetAddChunkId(), GetAddPrefix() and GetFullHash() are exposed so
41 // that these items can be generically compared with each other by
42 // SBAddPrefixLess() and SBAddPrefixHashLess().
48 SBAddPrefix(int32 id, SBPrefix p) : chunk_id(id), prefix(p) {}
49 SBAddPrefix() : chunk_id(), prefix() {}
51 int32 GetAddChunkId() const { return chunk_id; }
52 SBPrefix GetAddPrefix() const { return prefix; }
55 typedef std::deque<SBAddPrefix> SBAddPrefixes;
62 SBSubPrefix(int32 id, int32 add_id, int prefix)
63 : chunk_id(id), add_chunk_id(add_id), add_prefix(prefix) {}
64 SBSubPrefix() : chunk_id(), add_chunk_id(), add_prefix() {}
66 int32 GetAddChunkId() const { return add_chunk_id; }
67 SBPrefix GetAddPrefix() const { return add_prefix; }
70 typedef std::deque<SBSubPrefix> SBSubPrefixes;
72 struct SBAddFullHash {
77 SBAddFullHash(int32 id, base::Time r, const SBFullHash& h)
79 received(static_cast<int32>(r.ToTimeT())),
83 // Provided for ReadAddHashes() implementations, which already have
84 // an int32 for the time.
85 SBAddFullHash(int32 id, int32 r, const SBFullHash& h)
86 : chunk_id(id), received(r), full_hash(h) {}
88 SBAddFullHash() : chunk_id(), received(), full_hash() {}
90 int32 GetAddChunkId() const { return chunk_id; }
91 SBPrefix GetAddPrefix() const { return full_hash.prefix; }
94 struct SBSubFullHash {
99 SBSubFullHash(int32 id, int32 add_id, const SBFullHash& h)
100 : chunk_id(id), add_chunk_id(add_id), full_hash(h) {}
101 SBSubFullHash() : chunk_id(), add_chunk_id(), full_hash() {}
103 int32 GetAddChunkId() const { return add_chunk_id; }
104 SBPrefix GetAddPrefix() const { return full_hash.prefix; }
107 // Determine less-than based on add chunk and prefix.
108 template <class T, class U>
109 bool SBAddPrefixLess(const T& a, const U& b) {
110 if (a.GetAddChunkId() != b.GetAddChunkId())
111 return a.GetAddChunkId() < b.GetAddChunkId();
113 return a.GetAddPrefix() < b.GetAddPrefix();
116 // Determine less-than based on add chunk, prefix, and full hash.
117 // Prefix can compare differently than hash due to byte ordering,
118 // so it must take precedence.
119 template <class T, class U>
120 bool SBAddPrefixHashLess(const T& a, const U& b) {
121 if (SBAddPrefixLess(a, b))
124 if (SBAddPrefixLess(b, a))
127 return memcmp(a.full_hash.full_hash, b.full_hash.full_hash,
128 sizeof(a.full_hash.full_hash)) < 0;
131 // Process the lists for subs which knock out adds. For any item in
132 // |sub_prefixes| which has a match in |add_prefixes|, knock out the
133 // matched items from all vectors. Additionally remove items from
136 // TODO(shess): Since the prefixes are uniformly-distributed hashes,
137 // there aren't many ways to organize the inputs for efficient
138 // processing. For this reason, the vectors are sorted and processed
139 // in parallel. At this time this code does the sorting internally,
140 // but it might make sense to make sorting an API requirement so that
141 // the storage can optimize for it.
142 void SBProcessSubs(SBAddPrefixes* add_prefixes,
143 SBSubPrefixes* 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);
149 // Records a histogram of the number of items in |prefix_misses| which
150 // are not in |add_prefixes|.
151 void SBCheckPrefixMisses(const SBAddPrefixes& add_prefixes,
152 const std::set<SBPrefix>& prefix_misses);
154 // TODO(shess): This uses int32 rather than int because it's writing
155 // specifically-sized items to files. SBPrefix should likewise be
158 // Abstract interface for storing data.
159 class SafeBrowsingStore {
161 SafeBrowsingStore() {}
162 virtual ~SafeBrowsingStore() {}
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
170 virtual void Init(const base::FilePath& filename,
171 const base::Closure& corruption_callback) = 0;
173 // Deletes the files which back the store, returning true if
175 virtual bool Delete() = 0;
177 // Get all Add prefixes out from the store.
178 virtual bool GetAddPrefixes(SBAddPrefixes* add_prefixes) = 0;
180 // Get all add full-length hashes.
181 virtual bool GetAddFullHashes(
182 std::vector<SBAddFullHash>* add_full_hashes) = 0;
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;
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
194 virtual bool BeginChunk() = 0;
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;
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;
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;
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;
222 // May be called during update to verify that the storage is valid.
223 // Return true if the store seems valid. If corruption is detected,
224 // calls the corruption callback and return false.
225 // NOTE(shess): When storage was SQLite, there was no guarantee that
226 // a structurally sound database actually contained valid data,
227 // whereas SafeBrowsingStoreFile checksums the data. For now, this
228 // distinction doesn't matter.
229 virtual bool CheckValidity() = 0;
231 // Pass the collected chunks through SBPRocessSubs() and commit to
232 // permanent storage. The resulting add prefixes and hashes will be
233 // stored in |add_prefixes_result| and |add_full_hashes_result|.
234 // |pending_adds| is the set of full hashes which have been received
235 // since the previous update, and is provided as a convenience
236 // (could be written via WriteAddHash(), but that would flush the
237 // chunk to disk). |prefix_misses| is the set of prefixes where the
238 // |GetHash()| request returned no full hashes, used for diagnostic
240 virtual bool FinishUpdate(
241 const std::vector<SBAddFullHash>& pending_adds,
242 const std::set<SBPrefix>& prefix_misses,
243 SBAddPrefixes* add_prefixes_result,
244 std::vector<SBAddFullHash>* add_full_hashes_result) = 0;
246 // Cancel the update in process and remove any temporary disk
247 // storage, leaving the original data unmodified.
248 virtual bool CancelUpdate() = 0;
251 DISALLOW_COPY_AND_ASSIGN(SafeBrowsingStore);
254 #endif // CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_STORE_H_