1 // Copyright 2014 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 "components/crx_file/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( 22 base::StringPiece(id->begin() + i, id->begin() + i + 1), &val)) { 23 (*id)[i] = val + 'a'; 24 } else { 25 (*id)[i] = 'a'; 26 } 27 } 28 } 29 30 } // namespace 31 32 namespace crx_file { 33 namespace id_util { 34 35 // First 16 bytes of SHA256 hashed public key. 36 const size_t kIdSize = 16; 37 38 std::string GenerateId(const std::string& input) { 39 uint8 hash[kIdSize]; 40 crypto::SHA256HashString(input, hash, sizeof(hash)); 41 std::string output = 42 base::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] == L':') 64 path_str[0] = towupper(path_str[0]); 65 66 return base::FilePath(path_str); 67 #else 68 return path; 69 #endif 70 } 71 72 bool IdIsValid(const std::string& id) { 73 // Verify that the id is legal. 74 if (id.size() != (crx_file::id_util::kIdSize * 2)) 75 return false; 76 77 // We only support lowercase IDs, because IDs can be used as URL components 78 // (where GURL will lowercase it). 79 std::string temp = base::StringToLowerASCII(id); 80 for (size_t i = 0; i < temp.size(); i++) 81 if (temp[i] < 'a' || temp[i] > 'p') 82 return false; 83 84 return true; 85 } 86 87 } // namespace id_util 88 } // namespace crx_file 89