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      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.
      4 
      5 #include "sync/internal_api/syncapi_internal.h"
      6 
      7 #include "base/memory/scoped_ptr.h"
      8 #include "sync/protocol/password_specifics.pb.h"
      9 #include "sync/protocol/sync.pb.h"
     10 #include "sync/util/cryptographer.h"
     11 
     12 namespace syncer {
     13 
     14 namespace {
     15 
     16 bool EndsWithSpace(const std::string& string) {
     17   return !string.empty() && *string.rbegin() == ' ';
     18 }
     19 
     20 }
     21 
     22 sync_pb::PasswordSpecificsData* DecryptPasswordSpecifics(
     23     const sync_pb::EntitySpecifics& specifics, Cryptographer* crypto) {
     24   if (!specifics.has_password())
     25     return NULL;
     26   const sync_pb::PasswordSpecifics& password_specifics = specifics.password();
     27   if (!password_specifics.has_encrypted())
     28     return NULL;
     29   const sync_pb::EncryptedData& encrypted = password_specifics.encrypted();
     30   scoped_ptr<sync_pb::PasswordSpecificsData> data(
     31       new sync_pb::PasswordSpecificsData);
     32   if (!crypto->Decrypt(encrypted, data.get()))
     33     return NULL;
     34   return data.release();
     35 }
     36 
     37 // The list of names which are reserved for use by the server.
     38 static const char* kForbiddenServerNames[] = { "", ".", ".." };
     39 
     40 // When taking a name from the syncapi, append a space if it matches the
     41 // pattern of a server-illegal name followed by zero or more spaces.
     42 void SyncAPINameToServerName(const std::string& syncer_name,
     43                              std::string* out) {
     44   *out = syncer_name;
     45   if (IsNameServerIllegalAfterTrimming(*out))
     46     out->append(" ");
     47 }
     48 
     49 // In the reverse direction, if a server name matches the pattern of a
     50 // server-illegal name followed by one or more spaces, remove the trailing
     51 // space.
     52 void ServerNameToSyncAPIName(const std::string& server_name,
     53                              std::string* out) {
     54   CHECK(out);
     55   int length_to_copy = server_name.length();
     56   if (IsNameServerIllegalAfterTrimming(server_name) &&
     57       EndsWithSpace(server_name)) {
     58     --length_to_copy;
     59   }
     60   *out = server_name.substr(0, length_to_copy);
     61 }
     62 
     63 // Checks whether |name| is a server-illegal name followed by zero or more space
     64 // characters.  The three server-illegal names are the empty string, dot, and
     65 // dot-dot.  Very long names (>255 bytes in UTF-8 Normalization Form C) are
     66 // also illegal, but are not considered here.
     67 bool IsNameServerIllegalAfterTrimming(const std::string& name) {
     68   size_t untrimmed_count = name.find_last_not_of(' ') + 1;
     69   for (size_t i = 0; i < arraysize(kForbiddenServerNames); ++i) {
     70     if (name.compare(0, untrimmed_count, kForbiddenServerNames[i]) == 0)
     71       return true;
     72   }
     73   return false;
     74 }
     75 
     76 // Compare the values of two EntitySpecifics, accounting for encryption.
     77 bool AreSpecificsEqual(const Cryptographer* cryptographer,
     78                        const sync_pb::EntitySpecifics& left,
     79                        const sync_pb::EntitySpecifics& right) {
     80   // Note that we can't compare encrypted strings directly as they are seeded
     81   // with a random value.
     82   std::string left_plaintext, right_plaintext;
     83   if (left.has_encrypted()) {
     84     if (!cryptographer->CanDecrypt(left.encrypted())) {
     85       NOTREACHED() << "Attempting to compare undecryptable data.";
     86       return false;
     87     }
     88     left_plaintext = cryptographer->DecryptToString(left.encrypted());
     89   } else {
     90     left_plaintext = left.SerializeAsString();
     91   }
     92   if (right.has_encrypted()) {
     93     if (!cryptographer->CanDecrypt(right.encrypted())) {
     94       NOTREACHED() << "Attempting to compare undecryptable data.";
     95       return false;
     96     }
     97     right_plaintext = cryptographer->DecryptToString(right.encrypted());
     98   } else {
     99     right_plaintext = right.SerializeAsString();
    100   }
    101   if (left_plaintext == right_plaintext) {
    102     return true;
    103   }
    104   return false;
    105 }
    106 
    107 }  // namespace syncer
    108