src/signer_chain.cc

   1 /*
   2     Copyright (C) 2013 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 #include <fstream>
  21 #include <sstream>
  22 #include <boost/filesystem.hpp>
  23 #include <boost/algorithm/string.hpp>
  24 #include <openssl/sha.h>
  25 #include <openssl/bio.h>
  26 #include <openssl/evp.h>
  27 #include "KM_util.h"
  28 #include "signer_chain.h"
  29 #include "exceptions.h"
  30 #include "util.h"
  31
  32 using std::string;
  33 using std::ofstream;
  34 using std::ifstream;
  35 using std::stringstream;
  36 using std::cout;
  37
  38 static void command (string cmd)
  39 {
  40 #ifdef LIBDCP_WINDOWS
  41         /* We need to use CreateProcessW on Windows so that the UTF-8/16 mess
  42            is handled correctly.
  43         */
  44         int const wn = MultiByteToWideChar (CP_UTF8, 0, cmd.c_str(), -1, 0, 0);
  45         wchar_t* buffer = new wchar_t[wn];
  46         if (MultiByteToWideChar (CP_UTF8, 0, cmd.c_str(), -1, buffer, wn) == 0) {
  47                 delete[] buffer;
  48                 return;
  49         }
  50
  51         int code = 1;
  52
  53         STARTUPINFOW startup_info;
  54         memset (&startup_info, 0, sizeof (startup_info));
  55         startup_info.cb = sizeof (startup_info);
  56         PROCESS_INFORMATION process_info;
  57
  58         /* XXX: this doesn't actually seem to work; failing commands end up with
  59            a return code of 0
  60         */
  61         if (CreateProcessW (0, buffer, 0, 0, FALSE, CREATE_NO_WINDOW, 0, 0, &startup_info, &process_info)) {
  62                 WaitForSingleObject (process_info.hProcess, INFINITE);
  63                 DWORD c;
  64                 if (GetExitCodeProcess (process_info.hProcess, &c)) {
  65                         code = c;
  66                 }
  67                 CloseHandle (process_info.hProcess);
  68                 CloseHandle (process_info.hThread);
  69         }
  70
  71         delete[] buffer;
  72 #else
  73         cmd += " 2> /dev/null";
  74         int const r = system (cmd.c_str ());
  75         int const code = WEXITSTATUS (r);
  76 #endif
  77         if (code) {
  78                 stringstream s;
  79                 s << "error " << code << " in " << cmd << " within " << boost::filesystem::current_path();
  80                 throw libdcp::MiscError (s.str());
  81         }
  82 }
  83
  84 /** Extract a public key from a private key and create a SHA1 digest of it.
  85  *  @param key Private key
  86  *  @param openssl openssl binary name (or full path if openssl is not on the system path).
  87  *  @return SHA1 digest of corresponding public key, with escaped / characters.
  88  */
  89
  90 static string
  91 public_key_digest (boost::filesystem::path private_key, boost::filesystem::path openssl)
  92 {
  93         boost::filesystem::path public_name = private_key.string() + ".public";
  94
  95         /* Create the public key from the private key */
  96         stringstream s;
  97         s << "\"" << openssl.string() << "\" rsa -outform PEM -pubout -in " << private_key.string() << " -out " << public_name.string ();
  98         command (s.str().c_str ());
  99
 100         /* Read in the public key from the file */
 101
 102         string pub;
 103         ifstream f (public_name.string().c_str ());
 104         if (!f.good ()) {
 105                 throw libdcp::MiscError ("public key not found");
 106         }
 107
 108         bool read = false;
 109         while (f.good ()) {
 110                 string line;
 111                 getline (f, line);
 112                 if (line.length() >= 10 && line.substr(0, 10) == "-----BEGIN") {
 113                         read = true;
 114                 } else if (line.length() >= 8 && line.substr(0, 8) == "-----END") {
 115                         break;
 116                 } else if (read) {
 117                         pub += line;
 118                 }
 119         }
 120
 121         /* Decode the base64 of the public key */
 122
 123         unsigned char buffer[512];
 124         int const N = libdcp::base64_decode (pub, buffer, 1024);
 125
 126         /* Hash it with SHA1 (without the first 24 bytes, for reasons that are not entirely clear) */
 127
 128         SHA_CTX context;
 129         if (!SHA1_Init (&context)) {
 130                 throw libdcp::MiscError ("could not init SHA1 context");
 131         }
 132
 133         if (!SHA1_Update (&context, buffer + 24, N - 24)) {
 134                 throw libdcp::MiscError ("could not update SHA1 digest");
 135         }
 136
 137         unsigned char digest[SHA_DIGEST_LENGTH];
 138         if (!SHA1_Final (digest, &context)) {
 139                 throw libdcp::MiscError ("could not finish SHA1 digest");
 140         }
 141
 142         char digest_base64[64];
 143         string dig = Kumu::base64encode (digest, SHA_DIGEST_LENGTH, digest_base64, 64);
 144 #ifdef LIBDCP_WINDOWS
 145         boost::replace_all (dig, "/", "\\/");
 146 #else
 147         boost::replace_all (dig, "/", "\\\\/");
 148 #endif
 149         return dig;
 150 }
 151
 152 void
 153 libdcp::make_signer_chain (boost::filesystem::path directory, boost::filesystem::path openssl)
 154 {
 155         boost::filesystem::path const cwd = boost::filesystem::current_path ();
 156
 157         string quoted_openssl = "\"" + openssl.string() + "\"";
 158
 159         boost::filesystem::current_path (directory);
 160         command (quoted_openssl + " genrsa -out ca.key 2048");
 161
 162         {
 163                 ofstream f ("ca.cnf");
 164                 f << "[ req ]\n"
 165                   << "distinguished_name = req_distinguished_name\n"
 166                   << "x509_extensions   = v3_ca\n"
 167                   << "[ v3_ca ]\n"
 168                   << "basicConstraints = critical,CA:true,pathlen:3\n"
 169                   << "keyUsage = keyCertSign,cRLSign\n"
 170                   << "subjectKeyIdentifier = hash\n"
 171                   << "authorityKeyIdentifier = keyid:always,issuer:always\n"
 172                   << "[ req_distinguished_name ]\n"
 173                   << "O = Unique organization name\n"
 174                   << "OU = Organization unit\n"
 175                   << "CN = Entity and dnQualifier\n";
 176         }
 177
 178         string const ca_subject = "/O=example.org/OU=example.org/CN=.smpte-430-2.ROOT.NOT_FOR_PRODUCTION/dnQualifier=" + public_key_digest ("ca.key", openssl);
 179
 180         {
 181                 stringstream c;
 182                 c << quoted_openssl
 183                   << " req -new -x509 -sha256 -config ca.cnf -days 3650 -set_serial 5"
 184                   << " -subj " << ca_subject << " -key ca.key -outform PEM -out ca.self-signed.pem";
 185                 command (c.str().c_str());
 186         }
 187
 188         command (quoted_openssl + " genrsa -out intermediate.key 2048");
 189
 190         {
 191                 ofstream f ("intermediate.cnf");
 192                 f << "[ default ]\n"
 193                   << "distinguished_name = req_distinguished_name\n"
 194                   << "x509_extensions = v3_ca\n"
 195                   << "[ v3_ca ]\n"
 196                   << "basicConstraints = critical,CA:true,pathlen:2\n"
 197                   << "keyUsage = keyCertSign,cRLSign\n"
 198                   << "subjectKeyIdentifier = hash\n"
 199                   << "authorityKeyIdentifier = keyid:always,issuer:always\n"
 200                   << "[ req_distinguished_name ]\n"
 201                   << "O = Unique organization name\n"
 202                   << "OU = Organization unit\n"
 203                   << "CN = Entity and dnQualifier\n";
 204         }
 205
 206         string const inter_subject = "/O=example.org/OU=example.org/CN=.smpte-430-2.INTERMEDIATE.NOT_FOR_PRODUCTION/dnQualifier="
 207                 + public_key_digest ("intermediate.key", openssl);
 208
 209         {
 210                 stringstream s;
 211                 s << quoted_openssl
 212                   << " req -new -config intermediate.cnf -days 3649 -subj " << inter_subject << " -key intermediate.key -out intermediate.csr";
 213                 command (s.str().c_str());
 214         }
 215
 216
 217         command (
 218                 quoted_openssl +
 219                 " x509 -req -sha256 -days 3649 -CA ca.self-signed.pem -CAkey ca.key -set_serial 6"
 220                 " -in intermediate.csr -extfile intermediate.cnf -extensions v3_ca -out intermediate.signed.pem"
 221                 );
 222
 223         command (quoted_openssl + " genrsa -out leaf.key 2048");
 224
 225         {
 226                 ofstream f ("leaf.cnf");
 227                 f << "[ default ]\n"
 228                   << "distinguished_name = req_distinguished_name\n"
 229                   << "x509_extensions   = v3_ca\n"
 230                   << "[ v3_ca ]\n"
 231                   << "basicConstraints = critical,CA:false\n"
 232                   << "keyUsage = digitalSignature,keyEncipherment\n"
 233                   << "subjectKeyIdentifier = hash\n"
 234                   << "authorityKeyIdentifier = keyid,issuer:always\n"
 235                   << "[ req_distinguished_name ]\n"
 236                   << "O = Unique organization name\n"
 237                   << "OU = Organization unit\n"
 238                   << "CN = Entity and dnQualifier\n";
 239         }
 240
 241         string const leaf_subject = "/O=example.org/OU=example.org/CN=CS.smpte-430-2.LEAF.NOT_FOR_PRODUCTION/dnQualifier="
 242                 + public_key_digest ("leaf.key", openssl);
 243
 244         {
 245                 stringstream s;
 246                 s << quoted_openssl << " req -new -config leaf.cnf -days 3648 -subj " << leaf_subject << " -key leaf.key -outform PEM -out leaf.csr";
 247                 command (s.str().c_str());
 248         }
 249
 250         command (
 251                 quoted_openssl +
 252                 " x509 -req -sha256 -days 3648 -CA intermediate.signed.pem -CAkey intermediate.key"
 253                 " -set_serial 7 -in leaf.csr -extfile leaf.cnf -extensions v3_ca -out leaf.signed.pem"
 254                 );
 255
 256         boost::filesystem::current_path (cwd);
 257 }