blob: 46ff576124738611e3620f399dc28aeb55784884 [file] [log] [blame]
/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/openssl_certificate.h"
#if defined(WEBRTC_WIN)
// Must be included first before openssl headers.
#include "rtc_base/win32.h" // NOLINT
#endif // WEBRTC_WIN
#include <openssl/bio.h>
#include <openssl/bn.h>
#include <openssl/pem.h>
#include <time.h>
#include <memory>
#include "rtc_base/checks.h"
#include "rtc_base/crypto_random.h"
#include "rtc_base/logging.h"
#include "rtc_base/message_digest.h"
#include "rtc_base/openssl_digest.h"
#include "rtc_base/openssl_identity.h"
#include "rtc_base/openssl_utility.h"
namespace rtc {
namespace {
// Random bits for certificate serial number
static const int SERIAL_RAND_BITS = 64;
#if !defined(NDEBUG)
// Print a certificate to the log, for debugging.
static void PrintCert(X509* x509) {
BIO* temp_memory_bio = BIO_new(BIO_s_mem());
if (!temp_memory_bio) {
RTC_DLOG_F(LS_ERROR) << "Failed to allocate temporary memory bio";
return;
}
X509_print_ex(temp_memory_bio, x509, XN_FLAG_SEP_CPLUS_SPC, 0);
BIO_write(temp_memory_bio, "\0", 1);
char* buffer;
BIO_get_mem_data(temp_memory_bio, &buffer);
RTC_DLOG(LS_VERBOSE) << buffer;
BIO_free(temp_memory_bio);
}
#endif
// Generate a self-signed certificate, with the public key from the
// given key pair. Caller is responsible for freeing the returned object.
static X509* MakeCertificate(EVP_PKEY* pkey, const SSLIdentityParams& params) {
RTC_LOG(LS_INFO) << "Making certificate for " << params.common_name;
ASN1_INTEGER* asn1_serial_number = nullptr;
std::unique_ptr<BIGNUM, decltype(&::BN_free)> serial_number{nullptr,
::BN_free};
std::unique_ptr<X509, decltype(&::X509_free)> x509{nullptr, ::X509_free};
std::unique_ptr<X509_NAME, decltype(&::X509_NAME_free)> name{
nullptr, ::X509_NAME_free};
time_t epoch_off = 0; // Time offset since epoch.
x509.reset(X509_new());
if (x509 == nullptr) {
return nullptr;
}
if (!X509_set_pubkey(x509.get(), pkey)) {
return nullptr;
}
// serial number - temporary reference to serial number inside x509 struct
serial_number.reset(BN_new());
if (serial_number == nullptr ||
!BN_pseudo_rand(serial_number.get(), SERIAL_RAND_BITS, 0, 0) ||
(asn1_serial_number = X509_get_serialNumber(x509.get())) == nullptr ||
!BN_to_ASN1_INTEGER(serial_number.get(), asn1_serial_number)) {
return nullptr;
}
// Set version to X509.V3
if (!X509_set_version(x509.get(), 2L)) {
return nullptr;
}
// There are a lot of possible components for the name entries. In
// our P2P SSL mode however, the certificates are pre-exchanged
// (through the secure XMPP channel), and so the certificate
// identification is arbitrary. It can't be empty, so we set some
// arbitrary common_name. Note that this certificate goes out in
// clear during SSL negotiation, so there may be a privacy issue in
// putting anything recognizable here.
name.reset(X509_NAME_new());
if (name == nullptr ||
!X509_NAME_add_entry_by_NID(name.get(), NID_commonName, MBSTRING_UTF8,
(unsigned char*)params.common_name.c_str(),
-1, -1, 0) ||
!X509_set_subject_name(x509.get(), name.get()) ||
!X509_set_issuer_name(x509.get(), name.get())) {
return nullptr;
}
if (!X509_time_adj(X509_get_notBefore(x509.get()), params.not_before,
&epoch_off) ||
!X509_time_adj(X509_get_notAfter(x509.get()), params.not_after,
&epoch_off)) {
return nullptr;
}
if (!X509_sign(x509.get(), pkey, EVP_sha256())) {
return nullptr;
}
RTC_LOG(LS_INFO) << "Returning certificate";
return x509.release();
}
} // namespace
OpenSSLCertificate::OpenSSLCertificate(X509* x509) : x509_(x509) {
RTC_DCHECK(x509_ != nullptr);
X509_up_ref(x509_);
}
std::unique_ptr<OpenSSLCertificate> OpenSSLCertificate::Generate(
OpenSSLKeyPair* key_pair,
const SSLIdentityParams& params) {
SSLIdentityParams actual_params(params);
if (actual_params.common_name.empty()) {
// Use a random string, arbitrarily 8chars long.
actual_params.common_name = CreateRandomString(8);
}
X509* x509 = MakeCertificate(key_pair->pkey(), actual_params);
if (!x509) {
openssl::LogSSLErrors("Generating certificate");
return nullptr;
}
#if !defined(NDEBUG)
PrintCert(x509);
#endif
auto ret = std::make_unique<OpenSSLCertificate>(x509);
X509_free(x509);
return ret;
}
std::unique_ptr<OpenSSLCertificate> OpenSSLCertificate::FromPEMString(
absl::string_view pem_string) {
BIO* bio = BIO_new_mem_buf(const_cast<char*>(pem_string.data()), -1);
if (!bio) {
return nullptr;
}
BIO_set_mem_eof_return(bio, 0);
X509* x509 =
PEM_read_bio_X509(bio, nullptr, nullptr, const_cast<char*>("\0"));
BIO_free(bio); // Frees the BIO, but not the pointed-to string.
if (!x509) {
return nullptr;
}
auto ret = std::make_unique<OpenSSLCertificate>(x509);
X509_free(x509);
return ret;
}
// NOTE: This implementation only functions correctly after InitializeSSL
// and before CleanupSSL.
bool OpenSSLCertificate::GetSignatureDigestAlgorithm(
std::string* algorithm) const {
int nid = X509_get_signature_nid(x509_);
switch (nid) {
case NID_md5WithRSA:
case NID_md5WithRSAEncryption:
*algorithm = DIGEST_MD5;
break;
case NID_ecdsa_with_SHA1:
case NID_dsaWithSHA1:
case NID_dsaWithSHA1_2:
case NID_sha1WithRSA:
case NID_sha1WithRSAEncryption:
*algorithm = DIGEST_SHA_1;
break;
case NID_ecdsa_with_SHA224:
case NID_sha224WithRSAEncryption:
case NID_dsa_with_SHA224:
*algorithm = DIGEST_SHA_224;
break;
case NID_ecdsa_with_SHA256:
case NID_sha256WithRSAEncryption:
case NID_dsa_with_SHA256:
*algorithm = DIGEST_SHA_256;
break;
case NID_ecdsa_with_SHA384:
case NID_sha384WithRSAEncryption:
*algorithm = DIGEST_SHA_384;
break;
case NID_ecdsa_with_SHA512:
case NID_sha512WithRSAEncryption:
*algorithm = DIGEST_SHA_512;
break;
default:
// Unknown algorithm. There are several unhandled options that are less
// common and more complex.
RTC_LOG(LS_ERROR) << "Unknown signature algorithm NID: " << nid;
algorithm->clear();
return false;
}
return true;
}
bool OpenSSLCertificate::ComputeDigest(absl::string_view algorithm,
unsigned char* digest,
size_t size,
size_t* length) const {
return ComputeDigest(x509_, algorithm, digest, size, length);
}
bool OpenSSLCertificate::ComputeDigest(const X509* x509,
absl::string_view algorithm,
unsigned char* digest,
size_t size,
size_t* length) {
const EVP_MD* md = nullptr;
unsigned int n = 0;
if (!OpenSSLDigest::GetDigestEVP(algorithm, &md)) {
return false;
}
if (size < static_cast<size_t>(EVP_MD_size(md))) {
return false;
}
X509_digest(x509, md, digest, &n);
*length = n;
return true;
}
OpenSSLCertificate::~OpenSSLCertificate() {
X509_free(x509_);
}
std::unique_ptr<SSLCertificate> OpenSSLCertificate::Clone() const {
return std::make_unique<OpenSSLCertificate>(x509_);
}
std::string OpenSSLCertificate::ToPEMString() const {
BIO* bio = BIO_new(BIO_s_mem());
RTC_CHECK(bio);
RTC_CHECK(PEM_write_bio_X509(bio, x509_));
BIO_write(bio, "\0", 1);
char* buffer;
BIO_get_mem_data(bio, &buffer);
std::string ret(buffer);
BIO_free(bio);
return ret;
}
void OpenSSLCertificate::ToDER(Buffer* der_buffer) const {
// In case of failure, make sure to leave the buffer empty.
der_buffer->SetSize(0);
// Calculates the DER representation of the certificate, from scratch.
BIO* bio = BIO_new(BIO_s_mem());
RTC_CHECK(bio);
RTC_CHECK(i2d_X509_bio(bio, x509_));
char* data = nullptr;
size_t length = BIO_get_mem_data(bio, &data);
der_buffer->SetData(data, length);
BIO_free(bio);
}
bool OpenSSLCertificate::operator==(const OpenSSLCertificate& other) const {
return X509_cmp(x509_, other.x509_) == 0;
}
bool OpenSSLCertificate::operator!=(const OpenSSLCertificate& other) const {
return !(*this == other);
}
int64_t OpenSSLCertificate::CertificateExpirationTime() const {
ASN1_TIME* expire_time = X509_get_notAfter(x509_);
bool long_format;
if (expire_time->type == V_ASN1_UTCTIME) {
long_format = false;
} else if (expire_time->type == V_ASN1_GENERALIZEDTIME) {
long_format = true;
} else {
return -1;
}
return ASN1TimeToSec(expire_time->data, expire_time->length, long_format);
}
} // namespace rtc