src/certificate_chain.cc

   1 /*
   2     Copyright (C) 2013-2014 Carl Hetherington <cth@carlh.net>
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 /** @file  src/signer_chain.cc
  21  *  @brief Functions to make signer chains.
  22  */
  23
  24 #include "certificate_chain.h"
  25 #include "exceptions.h"
  26 #include "util.h"
  27 #include "KM_util.h"
  28 #include <openssl/sha.h>
  29 #include <openssl/bio.h>
  30 #include <openssl/evp.h>
  31 #include <boost/filesystem.hpp>
  32 #include <boost/algorithm/string.hpp>
  33 #include <fstream>
  34 #include <sstream>
  35
  36 using std::string;
  37 using std::ofstream;
  38 using std::ifstream;
  39 using std::stringstream;
  40
  41 /** Run a shell command.
  42  *  @param cmd Command to run (UTF8-encoded).
  43  */
  44 static void
  45 command (string cmd)
  46 {
  47 #ifdef LIBDCP_WINDOWS
  48         /* We need to use CreateProcessW on Windows so that the UTF-8/16 mess
  49            is handled correctly.
  50         */
  51         int const wn = MultiByteToWideChar (CP_UTF8, 0, cmd.c_str(), -1, 0, 0);
  52         wchar_t* buffer = new wchar_t[wn];
  53         if (MultiByteToWideChar (CP_UTF8, 0, cmd.c_str(), -1, buffer, wn) == 0) {
  54                 delete[] buffer;
  55                 return;
  56         }
  57
  58         int code = 1;
  59
  60         STARTUPINFOW startup_info;
  61         memset (&startup_info, 0, sizeof (startup_info));
  62         startup_info.cb = sizeof (startup_info);
  63         PROCESS_INFORMATION process_info;
  64
  65         /* XXX: this doesn't actually seem to work; failing commands end up with
  66            a return code of 0
  67         */
  68         if (CreateProcessW (0, buffer, 0, 0, FALSE, CREATE_NO_WINDOW, 0, 0, &startup_info, &process_info)) {
  69                 WaitForSingleObject (process_info.hProcess, INFINITE);
  70                 DWORD c;
  71                 if (GetExitCodeProcess (process_info.hProcess, &c)) {
  72                         code = c;
  73                 }
  74                 CloseHandle (process_info.hProcess);
  75                 CloseHandle (process_info.hThread);
  76         }
  77
  78         delete[] buffer;
  79 #else
  80         cmd += " 2> /dev/null";
  81         int const r = system (cmd.c_str ());
  82         int const code = WEXITSTATUS (r);
  83 #endif
  84         if (code) {
  85                 stringstream s;
  86                 s << "error " << code << " in " << cmd << " within " << boost::filesystem::current_path();
  87                 throw dcp::MiscError (s.str());
  88         }
  89 }
  90
  91 /** Extract a public key from a private key and create a SHA1 digest of it.
  92  *  @param private_key Private key
  93  *  @param openssl openssl binary name (or full path if openssl is not on the system path).
  94  *  @return SHA1 digest of corresponding public key, with escaped / characters.
  95  */
  96 static string
  97 public_key_digest (boost::filesystem::path private_key, boost::filesystem::path openssl)
  98 {
  99         boost::filesystem::path public_name = private_key.string() + ".public";
 100
 101         /* Create the public key from the private key */
 102         stringstream s;
 103         s << "\"" << openssl.string() << "\" rsa -outform PEM -pubout -in " << private_key.string() << " -out " << public_name.string ();
 104         command (s.str().c_str ());
 105
 106         /* Read in the public key from the file */
 107
 108         string pub;
 109         ifstream f (public_name.string().c_str ());
 110         if (!f.good ()) {
 111                 throw dcp::MiscError ("public key not found");
 112         }
 113
 114         bool read = false;
 115         while (f.good ()) {
 116                 string line;
 117                 getline (f, line);
 118                 if (line.length() >= 10 && line.substr(0, 10) == "-----BEGIN") {
 119                         read = true;
 120                 } else if (line.length() >= 8 && line.substr(0, 8) == "-----END") {
 121                         break;
 122                 } else if (read) {
 123                         pub += line;
 124                 }
 125         }
 126
 127         /* Decode the base64 of the public key */
 128
 129         unsigned char buffer[512];
 130         int const N = dcp::base64_decode (pub, buffer, 1024);
 131
 132         /* Hash it with SHA1 (without the first 24 bytes, for reasons that are not entirely clear) */
 133
 134         SHA_CTX context;
 135         if (!SHA1_Init (&context)) {
 136                 throw dcp::MiscError ("could not init SHA1 context");
 137         }
 138
 139         if (!SHA1_Update (&context, buffer + 24, N - 24)) {
 140                 throw dcp::MiscError ("could not update SHA1 digest");
 141         }
 142
 143         unsigned char digest[SHA_DIGEST_LENGTH];
 144         if (!SHA1_Final (digest, &context)) {
 145                 throw dcp::MiscError ("could not finish SHA1 digest");
 146         }
 147
 148         char digest_base64[64];
 149         string dig = Kumu::base64encode (digest, SHA_DIGEST_LENGTH, digest_base64, 64);
 150 #ifdef LIBDCP_WINDOWS
 151         boost::replace_all (dig, "/", "\\/");
 152 #else
 153         boost::replace_all (dig, "/", "\\\\/");
 154 #endif
 155         return dig;
 156 }
 157
 158 boost::filesystem::path
 159 dcp::make_certificate_chain (
 160         boost::filesystem::path openssl,
 161         string organisation,
 162         string organisational_unit,
 163         string root_common_name,
 164         string intermediate_common_name,
 165         string leaf_common_name
 166         )
 167 {
 168         boost::filesystem::path directory = boost::filesystem::temp_directory_path() / boost::filesystem::unique_path ();
 169         boost::filesystem::create_directories (directory);
 170
 171         boost::filesystem::path const cwd = boost::filesystem::current_path ();
 172         boost::filesystem::current_path (directory);
 173
 174         string quoted_openssl = "\"" + openssl.string() + "\"";
 175
 176         command (quoted_openssl + " genrsa -out ca.key 2048");
 177
 178         {
 179                 ofstream f ("ca.cnf");
 180                 f << "[ req ]\n"
 181                   << "distinguished_name = req_distinguished_name\n"
 182                   << "x509_extensions   = v3_ca\n"
 183                   << "[ v3_ca ]\n"
 184                   << "basicConstraints = critical,CA:true,pathlen:3\n"
 185                   << "keyUsage = keyCertSign,cRLSign\n"
 186                   << "subjectKeyIdentifier = hash\n"
 187                   << "authorityKeyIdentifier = keyid:always,issuer:always\n"
 188                   << "[ req_distinguished_name ]\n"
 189                   << "O = Unique organization name\n"
 190                   << "OU = Organization unit\n"
 191                   << "CN = Entity and dnQualifier\n";
 192         }
 193
 194         string const ca_subject = "/O=" + organisation +
 195                 "/OU=" + organisational_unit +
 196                 "/CN=" + root_common_name +
 197                 "/dnQualifier=" + public_key_digest ("ca.key", openssl);
 198
 199         {
 200                 stringstream c;
 201                 c << quoted_openssl
 202                   << " req -new -x509 -sha256 -config ca.cnf -days 3650 -set_serial 5"
 203                   << " -subj \"" << ca_subject << "\" -key ca.key -outform PEM -out ca.self-signed.pem";
 204                 command (c.str().c_str());
 205         }
 206
 207         command (quoted_openssl + " genrsa -out intermediate.key 2048");
 208
 209         {
 210                 ofstream f ("intermediate.cnf");
 211                 f << "[ default ]\n"
 212                   << "distinguished_name = req_distinguished_name\n"
 213                   << "x509_extensions = v3_ca\n"
 214                   << "[ v3_ca ]\n"
 215                   << "basicConstraints = critical,CA:true,pathlen:2\n"
 216                   << "keyUsage = keyCertSign,cRLSign\n"
 217                   << "subjectKeyIdentifier = hash\n"
 218                   << "authorityKeyIdentifier = keyid:always,issuer:always\n"
 219                   << "[ req_distinguished_name ]\n"
 220                   << "O = Unique organization name\n"
 221                   << "OU = Organization unit\n"
 222                   << "CN = Entity and dnQualifier\n";
 223         }
 224
 225         string const inter_subject = "/O=" + organisation +
 226                 "/OU=" + organisational_unit +
 227                 "/CN=" + intermediate_common_name +
 228                 "/dnQualifier=" + public_key_digest ("intermediate.key", openssl);
 229
 230         {
 231                 stringstream s;
 232                 s << quoted_openssl
 233                   << " req -new -config intermediate.cnf -days 3649 -subj \"" << inter_subject << "\" -key intermediate.key -out intermediate.csr";
 234                 command (s.str().c_str());
 235         }
 236
 237
 238         command (
 239                 quoted_openssl +
 240                 " x509 -req -sha256 -days 3649 -CA ca.self-signed.pem -CAkey ca.key -set_serial 6"
 241                 " -in intermediate.csr -extfile intermediate.cnf -extensions v3_ca -out intermediate.signed.pem"
 242                 );
 243
 244         command (quoted_openssl + " genrsa -out leaf.key 2048");
 245
 246         {
 247                 ofstream f ("leaf.cnf");
 248                 f << "[ default ]\n"
 249                   << "distinguished_name = req_distinguished_name\n"
 250                   << "x509_extensions   = v3_ca\n"
 251                   << "[ v3_ca ]\n"
 252                   << "basicConstraints = critical,CA:false\n"
 253                   << "keyUsage = digitalSignature,keyEncipherment\n"
 254                   << "subjectKeyIdentifier = hash\n"
 255                   << "authorityKeyIdentifier = keyid,issuer:always\n"
 256                   << "[ req_distinguished_name ]\n"
 257                   << "O = Unique organization name\n"
 258                   << "OU = Organization unit\n"
 259                   << "CN = Entity and dnQualifier\n";
 260         }
 261
 262         string const leaf_subject = "/O=" + organisation +
 263                 "/OU=" + organisational_unit +
 264                 "/CN=" + leaf_common_name +
 265                 "/dnQualifier=" + public_key_digest ("leaf.key", openssl);
 266
 267         {
 268                 stringstream s;
 269                 s << quoted_openssl << " req -new -config leaf.cnf -days 3648 -subj \"" << leaf_subject << "\" -key leaf.key -outform PEM -out leaf.csr";
 270                 command (s.str().c_str());
 271         }
 272
 273         command (
 274                 quoted_openssl +
 275                 " x509 -req -sha256 -days 3648 -CA intermediate.signed.pem -CAkey intermediate.key"
 276                 " -set_serial 7 -in leaf.csr -extfile leaf.cnf -extensions v3_ca -out leaf.signed.pem"
 277                 );
 278
 279         boost::filesystem::current_path (cwd);
 280
 281         return directory;
 282 }