2 Copyright (C) 2013-2016 Carl Hetherington <cth@carlh.net>
4 This file is part of libdcp.
6 libdcp is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 libdcp is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with libdcp. If not, see <http://www.gnu.org/licenses/>.
19 In addition, as a special exception, the copyright holders give
20 permission to link the code of portions of this program with the
21 OpenSSL library under certain conditions as described in each
22 individual source file, and distribute linked combinations
25 You must obey the GNU General Public License in all respects
26 for all of the code used other than OpenSSL. If you modify
27 file(s) with this exception, you may extend this exception to your
28 version of the file(s), but you are not obligated to do so. If you
29 do not wish to do so, delete this exception statement from your
30 version. If you delete this exception statement from all source
31 files in the program, then also delete it here.
34 /** @file src/signer_chain.cc
35 * @brief Functions to make signer chains.
38 #include "certificate_chain.h"
39 #include "exceptions.h"
41 #include "dcp_assert.h"
42 #include "compose.hpp"
43 #include <asdcp/KM_util.h>
44 #include <libcxml/cxml.h>
45 #include <libxml++/libxml++.h>
46 #include <xmlsec/xmldsig.h>
47 #include <xmlsec/dl.h>
48 #include <xmlsec/app.h>
49 #include <xmlsec/crypto.h>
50 #include <openssl/sha.h>
51 #include <openssl/bio.h>
52 #include <openssl/evp.h>
53 #include <openssl/pem.h>
54 #include <openssl/rsa.h>
55 #include <boost/filesystem.hpp>
56 #include <boost/algorithm/string.hpp>
57 #include <boost/foreach.hpp>
64 using std::runtime_error;
67 /** Run a shell command.
68 * @param cmd Command to run (UTF8-encoded).
74 /* We need to use CreateProcessW on Windows so that the UTF-8/16 mess
77 int const wn = MultiByteToWideChar (CP_UTF8, 0, cmd.c_str(), -1, 0, 0);
78 wchar_t* buffer = new wchar_t[wn];
79 if (MultiByteToWideChar (CP_UTF8, 0, cmd.c_str(), -1, buffer, wn) == 0) {
86 STARTUPINFOW startup_info;
87 memset (&startup_info, 0, sizeof (startup_info));
88 startup_info.cb = sizeof (startup_info);
89 PROCESS_INFORMATION process_info;
91 /* XXX: this doesn't actually seem to work; failing commands end up with
94 if (CreateProcessW (0, buffer, 0, 0, FALSE, CREATE_NO_WINDOW, 0, 0, &startup_info, &process_info)) {
95 WaitForSingleObject (process_info.hProcess, INFINITE);
97 if (GetExitCodeProcess (process_info.hProcess, &c)) {
100 CloseHandle (process_info.hProcess);
101 CloseHandle (process_info.hThread);
106 cmd += " 2> /dev/null";
107 int const r = system (cmd.c_str ());
108 int const code = WEXITSTATUS (r);
111 throw dcp::MiscError (String::compose ("error %1 in %2 within %3", code, cmd, boost::filesystem::current_path().string()));
115 /** Extract a public key from a private key and create a SHA1 digest of it.
116 * @param private_key Private key
117 * @param openssl openssl binary name (or full path if openssl is not on the system path).
118 * @return SHA1 digest of corresponding public key, with escaped / characters.
121 public_key_digest (boost::filesystem::path private_key, boost::filesystem::path openssl)
123 boost::filesystem::path public_name = private_key.string() + ".public";
125 /* Create the public key from the private key */
126 command (String::compose("\"%1\" rsa -outform PEM -pubout -in %2 -out %3", openssl.string(), private_key.string(), public_name.string ()));
128 /* Read in the public key from the file */
131 ifstream f (public_name.string().c_str ());
133 throw dcp::MiscError ("public key not found");
140 if (line.length() >= 10 && line.substr(0, 10) == "-----BEGIN") {
142 } else if (line.length() >= 8 && line.substr(0, 8) == "-----END") {
149 /* Decode the base64 of the public key */
151 unsigned char buffer[512];
152 int const N = dcp::base64_decode (pub, buffer, 1024);
154 /* Hash it with SHA1 (without the first 24 bytes, for reasons that are not entirely clear) */
157 if (!SHA1_Init (&context)) {
158 throw dcp::MiscError ("could not init SHA1 context");
161 if (!SHA1_Update (&context, buffer + 24, N - 24)) {
162 throw dcp::MiscError ("could not update SHA1 digest");
165 unsigned char digest[SHA_DIGEST_LENGTH];
166 if (!SHA1_Final (digest, &context)) {
167 throw dcp::MiscError ("could not finish SHA1 digest");
170 char digest_base64[64];
171 string dig = Kumu::base64encode (digest, SHA_DIGEST_LENGTH, digest_base64, 64);
172 #ifdef LIBDCP_WINDOWS
173 boost::replace_all (dig, "/", "\\/");
175 boost::replace_all (dig, "/", "\\\\/");
180 CertificateChain::CertificateChain (
181 boost::filesystem::path openssl,
183 string organisational_unit,
184 string root_common_name,
185 string intermediate_common_name,
186 string leaf_common_name
189 /* Valid for 40 years */
190 int const days = 365 * 40;
192 boost::filesystem::path directory = boost::filesystem::temp_directory_path() / boost::filesystem::unique_path ();
193 boost::filesystem::create_directories (directory);
195 boost::filesystem::path const cwd = boost::filesystem::current_path ();
196 boost::filesystem::current_path (directory);
198 string quoted_openssl = "\"" + openssl.string() + "\"";
200 command (quoted_openssl + " genrsa -out ca.key 2048");
203 ofstream f ("ca.cnf");
205 << "distinguished_name = req_distinguished_name\n"
206 << "x509_extensions = v3_ca\n"
207 << "string_mask = nombstr\n"
209 << "basicConstraints = critical,CA:true,pathlen:3\n"
210 << "keyUsage = keyCertSign,cRLSign\n"
211 << "subjectKeyIdentifier = hash\n"
212 << "authorityKeyIdentifier = keyid:always,issuer:always\n"
213 << "[ req_distinguished_name ]\n"
214 << "O = Unique organization name\n"
215 << "OU = Organization unit\n"
216 << "CN = Entity and dnQualifier\n";
219 string const ca_subject = "/O=" + organisation +
220 "/OU=" + organisational_unit +
221 "/CN=" + root_common_name +
222 "/dnQualifier=" + public_key_digest ("ca.key", openssl);
227 "%1 req -new -x509 -sha256 -config ca.cnf -days %2 -set_serial 5"
228 " -subj \"%3\" -key ca.key -outform PEM -out ca.self-signed.pem",
229 quoted_openssl, days, ca_subject
234 command (quoted_openssl + " genrsa -out intermediate.key 2048");
237 ofstream f ("intermediate.cnf");
239 << "distinguished_name = req_distinguished_name\n"
240 << "x509_extensions = v3_ca\n"
241 << "string_mask = nombstr\n"
243 << "basicConstraints = critical,CA:true,pathlen:2\n"
244 << "keyUsage = keyCertSign,cRLSign\n"
245 << "subjectKeyIdentifier = hash\n"
246 << "authorityKeyIdentifier = keyid:always,issuer:always\n"
247 << "[ req_distinguished_name ]\n"
248 << "O = Unique organization name\n"
249 << "OU = Organization unit\n"
250 << "CN = Entity and dnQualifier\n";
253 string const inter_subject = "/O=" + organisation +
254 "/OU=" + organisational_unit +
255 "/CN=" + intermediate_common_name +
256 "/dnQualifier=" + public_key_digest ("intermediate.key", openssl);
261 "%1 req -new -config intermediate.cnf -days %2 -subj \"%3\" -key intermediate.key -out intermediate.csr",
262 quoted_openssl, days - 1, inter_subject
269 "%1 x509 -req -sha256 -days %2 -CA ca.self-signed.pem -CAkey ca.key -set_serial 6"
270 " -in intermediate.csr -extfile intermediate.cnf -extensions v3_ca -out intermediate.signed.pem",
271 quoted_openssl, days - 1
275 command (quoted_openssl + " genrsa -out leaf.key 2048");
278 ofstream f ("leaf.cnf");
280 << "distinguished_name = req_distinguished_name\n"
281 << "x509_extensions = v3_ca\n"
282 << "string_mask = nombstr\n"
284 << "basicConstraints = critical,CA:false\n"
285 << "keyUsage = digitalSignature,keyEncipherment\n"
286 << "subjectKeyIdentifier = hash\n"
287 << "authorityKeyIdentifier = keyid,issuer:always\n"
288 << "[ req_distinguished_name ]\n"
289 << "O = Unique organization name\n"
290 << "OU = Organization unit\n"
291 << "CN = Entity and dnQualifier\n";
294 string const leaf_subject = "/O=" + organisation +
295 "/OU=" + organisational_unit +
296 "/CN=" + leaf_common_name +
297 "/dnQualifier=" + public_key_digest ("leaf.key", openssl);
302 "%1 req -new -config leaf.cnf -days %2 -subj \"%3\" -key leaf.key -outform PEM -out leaf.csr",
303 quoted_openssl, days - 2, leaf_subject
310 "%1 x509 -req -sha256 -days %2 -CA intermediate.signed.pem -CAkey intermediate.key"
311 " -set_serial 7 -in leaf.csr -extfile leaf.cnf -extensions v3_ca -out leaf.signed.pem",
312 quoted_openssl, days - 2
316 boost::filesystem::current_path (cwd);
318 _certificates.push_back (dcp::Certificate (dcp::file_to_string (directory / "ca.self-signed.pem")));
319 _certificates.push_back (dcp::Certificate (dcp::file_to_string (directory / "intermediate.signed.pem")));
320 _certificates.push_back (dcp::Certificate (dcp::file_to_string (directory / "leaf.signed.pem")));
322 _key = dcp::file_to_string (directory / "leaf.key");
324 boost::filesystem::remove_all (directory);
327 CertificateChain::CertificateChain (string s)
332 s = c.read_string (s);
333 _certificates.push_back (c);
334 } catch (MiscError& e) {
335 /* Failed to read a certificate, just stop */
340 /* This will throw an exception if the chain cannot be ordered */
344 /** @return Root certificate */
346 CertificateChain::root () const
348 DCP_ASSERT (!_certificates.empty());
349 return root_to_leaf().front ();
352 /** @return Leaf certificate */
354 CertificateChain::leaf () const
356 DCP_ASSERT (!_certificates.empty());
357 return root_to_leaf().back ();
360 /** @return Certificates in order from leaf to root */
361 CertificateChain::List
362 CertificateChain::leaf_to_root () const
364 List l = root_to_leaf ();
369 CertificateChain::List
370 CertificateChain::unordered () const
372 return _certificates;
375 /** Add a certificate to the chain.
376 * @param c Certificate to add.
379 CertificateChain::add (Certificate c)
381 _certificates.push_back (c);
384 /** Remove a certificate from the chain.
385 * @param c Certificate to remove.
388 CertificateChain::remove (Certificate c)
390 _certificates.remove (c);
393 /** Remove the i'th certificate in the list, as listed
397 CertificateChain::remove (int i)
399 List::iterator j = _certificates.begin ();
400 while (j != _certificates.end () && i > 0) {
405 if (j != _certificates.end ()) {
406 _certificates.erase (j);
411 CertificateChain::chain_valid () const
413 return chain_valid (_certificates);
416 /** Check to see if a chain is valid (i.e. root signs the intermediate, intermediate
417 * signs the leaf and so on) and that the private key (if there is one) matches the
419 * @return true if it's ok, false if not.
422 CertificateChain::chain_valid (List const & chain) const
424 /* Here I am taking a chain of certificates A/B/C/D and checking validity of B wrt A,
425 C wrt B and D wrt C. It also appears necessary to check the issuer of B/C/D matches
426 the subject of A/B/C; I don't understand why. I'm sure there's a better way of doing
427 this with OpenSSL but the documentation does not appear not likely to reveal it
431 X509_STORE* store = X509_STORE_new ();
433 throw MiscError ("could not create X509 store");
436 /* Put all the certificates into the store */
437 for (List::const_iterator i = chain.begin(); i != chain.end(); ++i) {
438 if (!X509_STORE_add_cert (store, i->x509 ())) {
439 X509_STORE_free (store);
444 /* Verify each one */
445 for (List::const_iterator i = chain.begin(); i != chain.end(); ++i) {
447 List::const_iterator j = i;
449 if (j == chain.end ()) {
453 X509_STORE_CTX* ctx = X509_STORE_CTX_new ();
455 X509_STORE_free (store);
456 throw MiscError ("could not create X509 store context");
459 X509_STORE_set_flags (store, 0);
460 if (!X509_STORE_CTX_init (ctx, store, j->x509(), 0)) {
461 X509_STORE_CTX_free (ctx);
462 X509_STORE_free (store);
463 throw MiscError ("could not initialise X509 store context");
466 int const v = X509_verify_cert (ctx);
467 X509_STORE_CTX_free (ctx);
470 X509_STORE_free (store);
474 /* I don't know why OpenSSL doesn't check this stuff
475 in verify_cert, but without these checks the
476 certificates_validation8 test fails.
478 if (j->issuer() != i->subject() || j->subject() == i->subject()) {
479 X509_STORE_free (store);
485 X509_STORE_free (store);
490 /** Check that there is a valid private key for the leaf certificate.
491 * Will return true if there are no certificates.
494 CertificateChain::private_key_valid () const
496 if (_certificates.empty ()) {
504 BIO* bio = BIO_new_mem_buf (const_cast<char *> (_key->c_str ()), -1);
506 throw MiscError ("could not create memory BIO");
509 RSA* private_key = PEM_read_bio_RSAPrivateKey (bio, 0, 0, 0);
514 RSA* public_key = leaf().public_key ();
516 #if OPENSSL_VERSION_NUMBER > 0x10100000L
517 BIGNUM const * private_key_n;
518 RSA_get0_key(private_key, &private_key_n, 0, 0);
519 BIGNUM const * public_key_n;
520 RSA_get0_key(public_key, &public_key_n, 0, 0);
521 if (!private_key_n || !public_key_n) {
524 bool const valid = !BN_cmp (private_key_n, public_key_n);
526 bool const valid = !BN_cmp (private_key->n, public_key->n);
534 CertificateChain::valid (string* reason) const
538 } catch (CertificateChainError& e) {
540 *reason = "certificates do not form a chain";
545 if (!private_key_valid ()) {
547 *reason = "private key does not exist, or does not match leaf certificate";
555 /** @return Certificates in order from root to leaf */
556 CertificateChain::List
557 CertificateChain::root_to_leaf () const
559 List rtl = _certificates;
562 if (chain_valid (rtl)) {
565 } while (std::next_permutation (rtl.begin(), rtl.end()));
567 throw CertificateChainError ("certificate chain is not consistent");
570 /** Add a <Signer> and <ds:Signature> nodes to an XML node.
571 * @param parent XML node to add to.
572 * @param standard INTEROP or SMPTE.
575 CertificateChain::sign (xmlpp::Element* parent, Standard standard) const
579 parent->add_child_text(" ");
580 xmlpp::Element* signer = parent->add_child("Signer");
581 signer->set_namespace_declaration ("http://www.w3.org/2000/09/xmldsig#", "dsig");
582 xmlpp::Element* data = signer->add_child("X509Data", "dsig");
583 xmlpp::Element* serial_element = data->add_child("X509IssuerSerial", "dsig");
584 serial_element->add_child("X509IssuerName", "dsig")->add_child_text (leaf().issuer());
585 serial_element->add_child("X509SerialNumber", "dsig")->add_child_text (leaf().serial());
586 data->add_child("X509SubjectName", "dsig")->add_child_text (leaf().subject());
592 parent->add_child_text("\n ");
593 xmlpp::Element* signature = parent->add_child("Signature");
594 signature->set_namespace_declaration ("http://www.w3.org/2000/09/xmldsig#", "dsig");
595 signature->set_namespace ("dsig");
596 parent->add_child_text("\n");
598 xmlpp::Element* signed_info = signature->add_child ("SignedInfo", "dsig");
599 signed_info->add_child("CanonicalizationMethod", "dsig")->set_attribute ("Algorithm", "http://www.w3.org/TR/2001/REC-xml-c14n-20010315");
601 if (standard == INTEROP) {
602 signed_info->add_child("SignatureMethod", "dsig")->set_attribute("Algorithm", "http://www.w3.org/2000/09/xmldsig#rsa-sha1");
604 signed_info->add_child("SignatureMethod", "dsig")->set_attribute("Algorithm", "http://www.w3.org/2001/04/xmldsig-more#rsa-sha256");
607 xmlpp::Element* reference = signed_info->add_child("Reference", "dsig");
608 reference->set_attribute ("URI", "");
610 xmlpp::Element* transforms = reference->add_child("Transforms", "dsig");
611 transforms->add_child("Transform", "dsig")->set_attribute (
612 "Algorithm", "http://www.w3.org/2000/09/xmldsig#enveloped-signature"
615 reference->add_child("DigestMethod", "dsig")->set_attribute("Algorithm", "http://www.w3.org/2000/09/xmldsig#sha1");
616 /* This will be filled in by the signing later */
617 reference->add_child("DigestValue", "dsig");
619 signature->add_child("SignatureValue", "dsig");
620 signature->add_child("KeyInfo", "dsig");
621 add_signature_value (signature, "dsig", true);
625 /** Sign an XML node.
627 * @param parent Node to sign.
628 * @param ns Namespace to use for the signature XML nodes.
631 CertificateChain::add_signature_value (xmlpp::Element* parent, string ns, bool add_indentation) const
633 cxml::Node cp (parent);
634 xmlpp::Node* key_info = cp.node_child("KeyInfo")->node ();
636 /* Add the certificate chain to the KeyInfo child node of parent */
637 BOOST_FOREACH (Certificate const & i, leaf_to_root ()) {
638 xmlpp::Element* data = key_info->add_child("X509Data", ns);
641 xmlpp::Element* serial = data->add_child("X509IssuerSerial", ns);
642 serial->add_child("X509IssuerName", ns)->add_child_text (i.issuer ());
643 serial->add_child("X509SerialNumber", ns)->add_child_text (i.serial ());
646 data->add_child("X509Certificate", ns)->add_child_text (i.certificate());
649 xmlSecDSigCtxPtr signature_context = xmlSecDSigCtxCreate (0);
650 if (signature_context == 0) {
651 throw MiscError ("could not create signature context");
654 signature_context->signKey = xmlSecCryptoAppKeyLoadMemory (
655 reinterpret_cast<const unsigned char *> (_key->c_str()), _key->size(), xmlSecKeyDataFormatPem, 0, 0, 0
658 if (signature_context->signKey == 0) {
659 throw runtime_error ("could not read private key");
662 if (add_indentation) {
665 int const r = xmlSecDSigCtxSign (signature_context, parent->cobj ());
667 throw MiscError (String::compose ("could not sign (%1)", r));
670 xmlSecDSigCtxDestroy (signature_context);
674 CertificateChain::chain () const
677 BOOST_FOREACH (Certificate const &i, root_to_leaf ()) {
678 o += i.certificate(true);