storage/browser/database/database_util.cc

   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 "storage/browser/database/database_util.h"
   6
   7 #include "base/basictypes.h"
   8 #include "base/strings/utf_string_conversions.h"
   9 #include "storage/browser/database/database_tracker.h"
  10 #include "storage/browser/database/vfs_backend.h"
  11 #include "storage/common/database/database_identifier.h"
  12
  13 namespace storage {
  14
  15 namespace {
  16
  17 bool IsSafeSuffix(const base::string16& suffix) {
  18   base::char16 prev_c = 0;
  19   for (base::string16::const_iterator it = suffix.begin();
  20       it < suffix.end(); ++it) {
  21     base::char16 c = *it;
  22     if (!(base::IsAsciiAlpha(c) || base::IsAsciiDigit(c) ||
  23           c == '-' || c == '.' || c == '_')) {
  24       return false;
  25     }
  26     if (c == '.' && prev_c == '.')
  27       return false;
  28     prev_c = c;
  29   }
  30   return true;
  31 }
  32
  33 }
  34
  35 const char DatabaseUtil::kJournalFileSuffix[] = "-journal";
  36
  37 bool DatabaseUtil::CrackVfsFileName(const base::string16& vfs_file_name,
  38                                     std::string* origin_identifier,
  39                                     base::string16* database_name,
  40                                     base::string16* sqlite_suffix) {
  41   // 'vfs_file_name' is of the form <origin_identifier>/<db_name>#<suffix>.
  42   // <suffix> is optional.
  43   DCHECK(!vfs_file_name.empty());
  44   size_t first_slash_index = vfs_file_name.find('/');
  45   size_t last_pound_index = vfs_file_name.rfind('#');
  46   // '/' and '#' must be present in the string. Also, the string cannot start
  47   // with a '/' (origin_identifier cannot be empty) and '/' must come before '#'
  48   if ((first_slash_index == base::string16::npos) ||
  49       (last_pound_index == base::string16::npos) ||
  50       (first_slash_index == 0) ||
  51       (first_slash_index > last_pound_index)) {
  52     return false;
  53   }
  54
  55   std::string origin_id = base::UTF16ToASCII(
  56         vfs_file_name.substr(0, first_slash_index));
  57   if (!IsValidOriginIdentifier(origin_id))
  58     return false;
  59
  60   base::string16 suffix = vfs_file_name.substr(
  61       last_pound_index + 1, vfs_file_name.length() - last_pound_index - 1);
  62   if (!IsSafeSuffix(suffix))
  63     return false;
  64
  65   if (origin_identifier)
  66     *origin_identifier = origin_id;
  67
  68   if (database_name) {
  69     *database_name = vfs_file_name.substr(
  70         first_slash_index + 1, last_pound_index - first_slash_index - 1);
  71   }
  72
  73   if (sqlite_suffix)
  74     *sqlite_suffix = suffix;
  75
  76   return true;
  77 }
  78
  79 base::FilePath DatabaseUtil::GetFullFilePathForVfsFile(
  80     DatabaseTracker* db_tracker, const base::string16& vfs_file_name) {
  81   std::string origin_identifier;
  82   base::string16 database_name;
  83   base::string16 sqlite_suffix;
  84   if (!CrackVfsFileName(vfs_file_name, &origin_identifier,
  85                         &database_name, &sqlite_suffix)) {
  86     return base::FilePath(); // invalid vfs_file_name
  87   }
  88
  89   base::FilePath full_path = db_tracker->GetFullDBFilePath(
  90       origin_identifier, database_name);
  91   if (!full_path.empty() && !sqlite_suffix.empty()) {
  92     DCHECK(full_path.Extension().empty());
  93     full_path = full_path.InsertBeforeExtensionASCII(
  94         base::UTF16ToASCII(sqlite_suffix));
  95   }
  96   // Watch out for directory traversal attempts from a compromised renderer.
  97   if (full_path.value().find(FILE_PATH_LITERAL("..")) !=
  98           base::FilePath::StringType::npos)
  99     return base::FilePath();
 100   return full_path;
 101 }
 102
 103 bool DatabaseUtil::IsValidOriginIdentifier(
 104     const std::string& origin_identifier) {
 105   return GetOriginFromIdentifier(origin_identifier).is_valid();
 106 }
 107
 108 }  // namespace storage