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
13namespace storage {
14
15namespace {
16
17bool 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 (!(IsAsciiAlpha(c) || 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
35const char DatabaseUtil::kJournalFileSuffix[] = "-journal";
36
37bool 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
79base::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
103bool DatabaseUtil::IsValidOriginIdentifier(
104    const std::string& origin_identifier) {
105  return GetOriginFromIdentifier(origin_identifier).is_valid();
106}
107
108}  // namespace storage
109