extensions/common/id_util.cc

   1 // Copyright (c) 2013 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 "extensions/common/id_util.h"
   6
   7 #include "base/files/file_path.h"
   8 #include "base/strings/string_number_conversions.h"
   9 #include "base/strings/string_util.h"
  10 #include "crypto/sha2.h"
  11
  12 namespace {
  13
  14 // Converts a normal hexadecimal string into the alphabet used by extensions.
  15 // We use the characters 'a'-'p' instead of '0'-'f' to avoid ever having a
  16 // completely numeric host, since some software interprets that as an IP
  17 // address.
  18 static void ConvertHexadecimalToIDAlphabet(std::string* id) {
  19   for (size_t i = 0; i < id->size(); ++i) {
  20     int val;
  21     if (base::HexStringToInt(base::StringPiece(id->begin() + i,
  22                                                id->begin() + i + 1),
  23                              &val)) {
  24       (*id)[i] = val + 'a';
  25     } else {
  26       (*id)[i] = 'a';
  27     }
  28   }
  29 }
  30
  31 }  // namespace
  32
  33 namespace extensions {
  34 namespace id_util {
  35
  36 // First 16 bytes of SHA256 hashed public key.
  37 const size_t kIdSize = 16;
  38
  39 std::string GenerateId(const std::string& input) {
  40   uint8 hash[kIdSize];
  41   crypto::SHA256HashString(input, hash, sizeof(hash));
  42   std::string output = StringToLowerASCII(base::HexEncode(hash, sizeof(hash)));
  43   ConvertHexadecimalToIDAlphabet(&output);
  44
  45   return output;
  46 }
  47
  48 std::string GenerateIdForPath(const base::FilePath& path) {
  49   base::FilePath new_path = MaybeNormalizePath(path);
  50   std::string path_bytes =
  51       std::string(reinterpret_cast<const char*>(new_path.value().data()),
  52                   new_path.value().size() * sizeof(base::FilePath::CharType));
  53   return GenerateId(path_bytes);
  54 }
  55
  56 base::FilePath MaybeNormalizePath(const base::FilePath& path) {
  57 #if defined(OS_WIN)
  58   // Normalize any drive letter to upper-case. We do this for consistency with
  59   // net_utils::FilePathToFileURL(), which does the same thing, to make string
  60   // comparisons simpler.
  61   base::FilePath::StringType path_str = path.value();
  62   if (path_str.size() >= 2 && path_str[0] >= L'a' && path_str[0] <= L'z' &&
  63       path_str[1] == ':')
  64     path_str[0] += ('A' - 'a');
  65
  66   return base::FilePath(path_str);
  67 #else
  68   return path;
  69 #endif
  70 }
  71
  72 }  // namespace id_util
  73 }  // namespace extensions