mini_ssl.c

#define RSTRING_NOT_MODIFIED 1

#include <ruby.h>
#include <ruby/version.h>

#if RUBY_API_VERSION_MAJOR == 1
#include <rubyio.h>
#else
#include <ruby/io.h>
#endif

#ifdef HAVE_OPENSSL_BIO_H

#include <openssl/bio.h>
#include <openssl/ssl.h>
#include <openssl/dh.h>
#include <openssl/err.h>
#include <openssl/x509.h>

#ifndef SSL_OP_NO_COMPRESSION
#define SSL_OP_NO_COMPRESSION 0
#endif

typedef struct {
  BIO* read;
  BIO* write;
  SSL* ssl;
  SSL_CTX* ctx;
} ms_conn;

typedef struct {
  unsigned char* buf;
  int bytes;
} ms_cert_buf;

void engine_free(ms_conn* conn) {
  ms_cert_buf* cert_buf = (ms_cert_buf*)SSL_get_app_data(conn->ssl);
  if(cert_buf) {
    OPENSSL_free(cert_buf->buf);
    free(cert_buf);
  }
  SSL_free(conn->ssl);
  SSL_CTX_free(conn->ctx);

  free(conn);
}

ms_conn* engine_alloc(VALUE klass, VALUE* obj) {
  ms_conn* conn;

  *obj = Data_Make_Struct(klass, ms_conn, 0, engine_free, conn);

  conn->read = BIO_new(BIO_s_mem());
  BIO_set_nbio(conn->read, 1);

  conn->write = BIO_new(BIO_s_mem());
  BIO_set_nbio(conn->write, 1);

  conn->ssl = 0;
  conn->ctx = 0;

  return conn;
}

DH *get_dh2048(void) {
  /* `openssl dhparam -C 2048`
   * -----BEGIN DH PARAMETERS-----
   * MIIBCAKCAQEAjmh1uQHdTfxOyxEbKAV30fUfzqMDF/ChPzjfyzl2jcrqQMhrk76o
   * 2NPNXqxHwsddMZ1RzvU8/jl+uhRuPWjXCFZbhET4N1vrviZM3VJhV8PPHuiVOACO
   * y32jFd+Szx4bo2cXSK83hJ6jRd+0asP1awWjz9/06dFkrILCXMIfQLo0D8rqmppn
   * EfDDAwuudCpM9kcDmBRAm9JsKbQ6gzZWjkc5+QWSaQofojIHbjvj3xzguaCJn+oQ
   * vHWM+hsAnaOgEwCyeZ3xqs+/5lwSbkE/tqJW98cEZGygBUVo9jxZRZx6KOfjpdrb
   * yenO9LJr/qtyrZB31WJbqxI0m0AKTAO8UwIBAg==
   * -----END DH PARAMETERS-----
   */
  static unsigned char dh2048_p[] = {
    0x8E, 0x68, 0x75, 0xB9, 0x01, 0xDD, 0x4D, 0xFC, 0x4E, 0xCB,
    0x11, 0x1B, 0x28, 0x05, 0x77, 0xD1, 0xF5, 0x1F, 0xCE, 0xA3,
    0x03, 0x17, 0xF0, 0xA1, 0x3F, 0x38, 0xDF, 0xCB, 0x39, 0x76,
    0x8D, 0xCA, 0xEA, 0x40, 0xC8, 0x6B, 0x93, 0xBE, 0xA8, 0xD8,
    0xD3, 0xCD, 0x5E, 0xAC, 0x47, 0xC2, 0xC7, 0x5D, 0x31, 0x9D,
    0x51, 0xCE, 0xF5, 0x3C, 0xFE, 0x39, 0x7E, 0xBA, 0x14, 0x6E,
    0x3D, 0x68, 0xD7, 0x08, 0x56, 0x5B, 0x84, 0x44, 0xF8, 0x37,
    0x5B, 0xEB, 0xBE, 0x26, 0x4C, 0xDD, 0x52, 0x61, 0x57, 0xC3,
    0xCF, 0x1E, 0xE8, 0x95, 0x38, 0x00, 0x8E, 0xCB, 0x7D, 0xA3,
    0x15, 0xDF, 0x92, 0xCF, 0x1E, 0x1B, 0xA3, 0x67, 0x17, 0x48,
    0xAF, 0x37, 0x84, 0x9E, 0xA3, 0x45, 0xDF, 0xB4, 0x6A, 0xC3,
    0xF5, 0x6B, 0x05, 0xA3, 0xCF, 0xDF, 0xF4, 0xE9, 0xD1, 0x64,
    0xAC, 0x82, 0xC2, 0x5C, 0xC2, 0x1F, 0x40, 0xBA, 0x34, 0x0F,
    0xCA, 0xEA, 0x9A, 0x9A, 0x67, 0x11, 0xF0, 0xC3, 0x03, 0x0B,
    0xAE, 0x74, 0x2A, 0x4C, 0xF6, 0x47, 0x03, 0x98, 0x14, 0x40,
    0x9B, 0xD2, 0x6C, 0x29, 0xB4, 0x3A, 0x83, 0x36, 0x56, 0x8E,
    0x47, 0x39, 0xF9, 0x05, 0x92, 0x69, 0x0A, 0x1F, 0xA2, 0x32,
    0x07, 0x6E, 0x3B, 0xE3, 0xDF, 0x1C, 0xE0, 0xB9, 0xA0, 0x89,
    0x9F, 0xEA, 0x10, 0xBC, 0x75, 0x8C, 0xFA, 0x1B, 0x00, 0x9D,
    0xA3, 0xA0, 0x13, 0x00, 0xB2, 0x79, 0x9D, 0xF1, 0xAA, 0xCF,
    0xBF, 0xE6, 0x5C, 0x12, 0x6E, 0x41, 0x3F, 0xB6, 0xA2, 0x56,
    0xF7, 0xC7, 0x04, 0x64, 0x6C, 0xA0, 0x05, 0x45, 0x68, 0xF6,
    0x3C, 0x59, 0x45, 0x9C, 0x7A, 0x28, 0xE7, 0xE3, 0xA5, 0xDA,
    0xDB, 0xC9, 0xE9, 0xCE, 0xF4, 0xB2, 0x6B, 0xFE, 0xAB, 0x72,
    0xAD, 0x90, 0x77, 0xD5, 0x62, 0x5B, 0xAB, 0x12, 0x34, 0x9B,
    0x40, 0x0A, 0x4C, 0x03, 0xBC, 0x53
  };
  static unsigned char dh2048_g[] = { 0x02 };

  DH *dh;
#if !(OPENSSL_VERSION_NUMBER < 0x10100005L || defined(LIBRESSL_VERSION_NUMBER))
  BIGNUM *p, *g;
#endif

  dh = DH_new();

#if OPENSSL_VERSION_NUMBER < 0x10100005L || defined(LIBRESSL_VERSION_NUMBER)
  dh->p = BN_bin2bn(dh2048_p, sizeof(dh2048_p), NULL);
  dh->g = BN_bin2bn(dh2048_g, sizeof(dh2048_g), NULL);

  if ((dh->p == NULL) || (dh->g == NULL)) {
    DH_free(dh);
    return NULL;
  }
#else
  p = BN_bin2bn(dh2048_p, sizeof(dh2048_p), NULL);
  g = BN_bin2bn(dh2048_g, sizeof(dh2048_g), NULL);

  if (p == NULL || g == NULL || !DH_set0_pqg(dh, p, NULL, g)) {
    DH_free(dh);
    BN_free(p);
    BN_free(g);
    return NULL;
  }
#endif

  return dh;
}

static int engine_verify_callback(int preverify_ok, X509_STORE_CTX* ctx) {
  X509* err_cert;
  SSL* ssl;
  int bytes;
  unsigned char* buf = NULL;

  if(!preverify_ok) {
    err_cert = X509_STORE_CTX_get_current_cert(ctx);
    if(err_cert) {
      /*
       * Save the failed certificate for inspection/logging.
       */
      bytes = i2d_X509(err_cert, &buf);
      if(bytes > 0) {
        ms_cert_buf* cert_buf = (ms_cert_buf*)malloc(sizeof(ms_cert_buf));
        cert_buf->buf = buf;
        cert_buf->bytes = bytes;
        ssl = X509_STORE_CTX_get_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
        SSL_set_app_data(ssl, cert_buf);
      }
    }
  }

  return preverify_ok;
}

VALUE engine_init_server(VALUE self, VALUE mini_ssl_ctx) {
  VALUE obj, session_id_bytes;
  SSL_CTX* ctx;
  SSL* ssl;
  int min, ssl_options;

  ms_conn* conn = engine_alloc(self, &obj);

  ID sym_key = rb_intern("key");
  VALUE key = rb_funcall(mini_ssl_ctx, sym_key, 0);

  StringValue(key);

  ID sym_cert = rb_intern("cert");
  VALUE cert = rb_funcall(mini_ssl_ctx, sym_cert, 0);

  StringValue(cert);

  ID sym_ca = rb_intern("ca");
  VALUE ca = rb_funcall(mini_ssl_ctx, sym_ca, 0);

  ID sym_verify_mode = rb_intern("verify_mode");
  VALUE verify_mode = rb_funcall(mini_ssl_ctx, sym_verify_mode, 0);

  ID sym_ssl_cipher_filter = rb_intern("ssl_cipher_filter");
  VALUE ssl_cipher_filter = rb_funcall(mini_ssl_ctx, sym_ssl_cipher_filter, 0);

  ID sym_no_tlsv1 = rb_intern("no_tlsv1");
  VALUE no_tlsv1 = rb_funcall(mini_ssl_ctx, sym_no_tlsv1, 0);

  ID sym_no_tlsv1_1 = rb_intern("no_tlsv1_1");
  VALUE no_tlsv1_1 = rb_funcall(mini_ssl_ctx, sym_no_tlsv1_1, 0);

#ifdef HAVE_TLS_SERVER_METHOD
  ctx = SSL_CTX_new(TLS_server_method());
#else
  ctx = SSL_CTX_new(SSLv23_server_method());
#endif
  conn->ctx = ctx;

  SSL_CTX_use_certificate_chain_file(ctx, RSTRING_PTR(cert));
  SSL_CTX_use_PrivateKey_file(ctx, RSTRING_PTR(key), SSL_FILETYPE_PEM);

  if (!NIL_P(ca)) {
    StringValue(ca);
    SSL_CTX_load_verify_locations(ctx, RSTRING_PTR(ca), NULL);
  }

  ssl_options = SSL_OP_CIPHER_SERVER_PREFERENCE | SSL_OP_SINGLE_ECDH_USE | SSL_OP_NO_COMPRESSION;

#ifdef HAVE_SSL_CTX_SET_MIN_PROTO_VERSION
  if (RTEST(no_tlsv1_1)) {
    min = TLS1_2_VERSION;
  }
  else if (RTEST(no_tlsv1)) {
    min = TLS1_1_VERSION;
  }
  else {
    min = TLS1_VERSION;
  }

  SSL_CTX_set_min_proto_version(ctx, min);

  SSL_CTX_set_options(ctx, ssl_options);

#else
  /* As of 1.0.2f, SSL_OP_SINGLE_DH_USE key use is always on */
  ssl_options |= SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_SINGLE_DH_USE;

  if (RTEST(no_tlsv1)) {
    ssl_options |= SSL_OP_NO_TLSv1;
  }
  if(RTEST(no_tlsv1_1)) {
    ssl_options |= SSL_OP_NO_TLSv1 | SSL_OP_NO_TLSv1_1;
  }
  SSL_CTX_set_options(ctx, ssl_options);
#endif

  SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF);

  if (!NIL_P(ssl_cipher_filter)) {
    StringValue(ssl_cipher_filter);
    SSL_CTX_set_cipher_list(ctx, RSTRING_PTR(ssl_cipher_filter));
  }
  else {
    SSL_CTX_set_cipher_list(ctx, "HIGH:!aNULL@STRENGTH");
  }

  // Random.bytes available in Ruby 2.5 and later, Random::DEFAULT deprecated in 3.0
  session_id_bytes = rb_funcall(
#ifdef HAVE_RANDOM_BYTES
    rb_cRandom,
#else
    rb_const_get(rb_cRandom, rb_intern_const("DEFAULT")),
#endif
    rb_intern_const("bytes"),
    1, ULL2NUM(SSL_MAX_SSL_SESSION_ID_LENGTH));

  SSL_CTX_set_session_id_context(ctx,
                                 (unsigned char *) RSTRING_PTR(session_id_bytes),
                                 SSL_MAX_SSL_SESSION_ID_LENGTH);

  DH *dh = get_dh2048();
  SSL_CTX_set_tmp_dh(ctx, dh);

#if OPENSSL_VERSION_NUMBER < 0x10002000L
  // Remove this case if OpenSSL 1.0.1 (now EOL) support is no
  // longer needed.
  EC_KEY *ecdh = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
  if (ecdh) {
    SSL_CTX_set_tmp_ecdh(ctx, ecdh);
    EC_KEY_free(ecdh);
  }
#elif OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
  // Prior to OpenSSL 1.1.0, servers must manually enable server-side ECDH
  // negotiation.
  SSL_CTX_set_ecdh_auto(ctx, 1);
#endif

  ssl = SSL_new(ctx);
  conn->ssl = ssl;
  SSL_set_app_data(ssl, NULL);

  if (NIL_P(verify_mode)) {
    /* SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL); */
  } else {
    SSL_set_verify(ssl, NUM2INT(verify_mode), engine_verify_callback);
  }

  SSL_set_bio(ssl, conn->read, conn->write);

  SSL_set_accept_state(ssl);
  return obj;
}

VALUE engine_init_client(VALUE klass) {
  VALUE obj;
  ms_conn* conn = engine_alloc(klass, &obj);
#ifdef HAVE_DTLS_METHOD
  conn->ctx = SSL_CTX_new(DTLS_method());
#else
  conn->ctx = SSL_CTX_new(DTLSv1_method());
#endif
  conn->ssl = SSL_new(conn->ctx);
  SSL_set_app_data(conn->ssl, NULL);
  SSL_set_verify(conn->ssl, SSL_VERIFY_NONE, NULL);

  SSL_set_bio(conn->ssl, conn->read, conn->write);

  SSL_set_connect_state(conn->ssl);
  return obj;
}

VALUE engine_inject(VALUE self, VALUE str) {
  ms_conn* conn;
  long used;

  Data_Get_Struct(self, ms_conn, conn);

  StringValue(str);

  used = BIO_write(conn->read, RSTRING_PTR(str), (int)RSTRING_LEN(str));

  if(used == 0 || used == -1) {
    return Qfalse;
  }

  return INT2FIX(used);
}

static VALUE eError;

void raise_error(SSL* ssl, int result) {
  char buf[512];
  char msg[512];
  const char* err_str;
  int err = errno;
  int ssl_err = SSL_get_error(ssl, result);
  int verify_err = (int) SSL_get_verify_result(ssl);

  if(SSL_ERROR_SYSCALL == ssl_err) {
    snprintf(msg, sizeof(msg), "System error: %s - %d", strerror(err), err);

  } else if(SSL_ERROR_SSL == ssl_err) {
    if(X509_V_OK != verify_err) {
      err_str = X509_verify_cert_error_string(verify_err);
      snprintf(msg, sizeof(msg),
               "OpenSSL certificate verification error: %s - %d",
               err_str, verify_err);

    } else {
      err = (int) ERR_get_error();
      ERR_error_string_n(err, buf, sizeof(buf));
      snprintf(msg, sizeof(msg), "OpenSSL error: %s - %d", buf, err);

    }
  } else {
    snprintf(msg, sizeof(msg), "Unknown OpenSSL error: %d", ssl_err);
  }

  ERR_clear_error();
  rb_raise(eError, "%s", msg);
}

VALUE engine_read(VALUE self) {
  ms_conn* conn;
  char buf[512];
  int bytes, error;

  Data_Get_Struct(self, ms_conn, conn);

  ERR_clear_error();

  bytes = SSL_read(conn->ssl, (void*)buf, sizeof(buf));

  if(bytes > 0) {
    return rb_str_new(buf, bytes);
  }

  if(SSL_want_read(conn->ssl)) return Qnil;

  error = SSL_get_error(conn->ssl, bytes);

  if(error == SSL_ERROR_ZERO_RETURN) {
    rb_eof_error();
  } else {
    raise_error(conn->ssl, bytes);
  }

  return Qnil;
}

VALUE engine_write(VALUE self, VALUE str) {
  ms_conn* conn;
  int bytes;

  Data_Get_Struct(self, ms_conn, conn);

  StringValue(str);

  ERR_clear_error();

  bytes = SSL_write(conn->ssl, (void*)RSTRING_PTR(str), (int)RSTRING_LEN(str));
  if(bytes > 0) {
    return INT2FIX(bytes);
  }

  if(SSL_want_write(conn->ssl)) return Qnil;

  raise_error(conn->ssl, bytes);

  return Qnil;
}

VALUE engine_extract(VALUE self) {
  ms_conn* conn;
  int bytes;
  size_t pending;
  char buf[512];

  Data_Get_Struct(self, ms_conn, conn);

  pending = BIO_pending(conn->write);
  if(pending > 0) {
    bytes = BIO_read(conn->write, buf, sizeof(buf));
    if(bytes > 0) {
      return rb_str_new(buf, bytes);
    } else if(!BIO_should_retry(conn->write)) {
      raise_error(conn->ssl, bytes);
    }
  }

  return Qnil;
}

VALUE engine_shutdown(VALUE self) {
  ms_conn* conn;
  int ok;

  Data_Get_Struct(self, ms_conn, conn);

  ERR_clear_error();

  ok = SSL_shutdown(conn->ssl);
  if (ok == 0) {
    return Qfalse;
  }

  return Qtrue;
}

VALUE engine_init(VALUE self) {
  ms_conn* conn;

  Data_Get_Struct(self, ms_conn, conn);

  return SSL_in_init(conn->ssl) ? Qtrue : Qfalse;
}

VALUE engine_peercert(VALUE self) {
  ms_conn* conn;
  X509* cert;
  int bytes;
  unsigned char* buf = NULL;
  ms_cert_buf* cert_buf = NULL;
  VALUE rb_cert_buf;

  Data_Get_Struct(self, ms_conn, conn);

  cert = SSL_get_peer_certificate(conn->ssl);
  if(!cert) {
    /*
     * See if there was a failed certificate associated with this client.
     */
    cert_buf = (ms_cert_buf*)SSL_get_app_data(conn->ssl);
    if(!cert_buf) {
      return Qnil;
    }
    buf = cert_buf->buf;
    bytes = cert_buf->bytes;

  } else {
    bytes = i2d_X509(cert, &buf);
    X509_free(cert);

    if(bytes < 0) {
      return Qnil;
    }
  }

  rb_cert_buf = rb_str_new((const char*)(buf), bytes);
  if(!cert_buf) {
    OPENSSL_free(buf);
  }

  return rb_cert_buf;
}

VALUE noop(VALUE self) {
  return Qnil;
}

void Init_mini_ssl(VALUE puma) {
  VALUE mod, eng;

/* Fake operation for documentation (RDoc, YARD) */
#if 0 == 1
  puma = rb_define_module("Puma");
#endif

  SSL_library_init();
  OpenSSL_add_ssl_algorithms();
  SSL_load_error_strings();
  ERR_load_crypto_strings();

  mod = rb_define_module_under(puma, "MiniSSL");
  eng = rb_define_class_under(mod, "Engine", rb_cObject);

  // OpenSSL Build / Runtime/Load versions

  /* Version of OpenSSL that Puma was compiled with */
  rb_define_const(mod, "OPENSSL_VERSION", rb_str_new2(OPENSSL_VERSION_TEXT));

#if !defined(LIBRESSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER >= 0x10100000
  /* Version of OpenSSL that Puma loaded with */
  rb_define_const(mod, "OPENSSL_LIBRARY_VERSION", rb_str_new2(OpenSSL_version(OPENSSL_VERSION)));
#else
  rb_define_const(mod, "OPENSSL_LIBRARY_VERSION", rb_str_new2(SSLeay_version(SSLEAY_VERSION)));
#endif

#if defined(OPENSSL_NO_SSL3) || defined(OPENSSL_NO_SSL3_METHOD)
  /* True if SSL3 is not available */
  rb_define_const(mod, "OPENSSL_NO_SSL3", Qtrue);
#else
  rb_define_const(mod, "OPENSSL_NO_SSL3", Qfalse);
#endif

#if defined(OPENSSL_NO_TLS1) || defined(OPENSSL_NO_TLS1_METHOD)
  /* True if TLS1 is not available */
  rb_define_const(mod, "OPENSSL_NO_TLS1", Qtrue);
#else
  rb_define_const(mod, "OPENSSL_NO_TLS1", Qfalse);
#endif

#if defined(OPENSSL_NO_TLS1_1) || defined(OPENSSL_NO_TLS1_1_METHOD)
  /* True if TLS1_1 is not available */
  rb_define_const(mod, "OPENSSL_NO_TLS1_1", Qtrue);
#else
  rb_define_const(mod, "OPENSSL_NO_TLS1_1", Qfalse);
#endif

  rb_define_singleton_method(mod, "check", noop, 0);

  eError = rb_define_class_under(mod, "SSLError", rb_eStandardError);

  rb_define_singleton_method(eng, "server", engine_init_server, 1);
  rb_define_singleton_method(eng, "client", engine_init_client, 0);

  rb_define_method(eng, "inject", engine_inject, 1);
  rb_define_method(eng, "read",  engine_read, 0);

  rb_define_method(eng, "write",  engine_write, 1);
  rb_define_method(eng, "extract", engine_extract, 0);

  rb_define_method(eng, "shutdown", engine_shutdown, 0);

  rb_define_method(eng, "init?", engine_init, 0);

  rb_define_method(eng, "peercert", engine_peercert, 0);
}

#else

VALUE raise_error(VALUE self) {
  rb_raise(rb_eStandardError, "SSL not available in this build");
  return Qnil;
}

void Init_mini_ssl(VALUE puma) {
  VALUE mod;

  mod = rb_define_module_under(puma, "MiniSSL");
  rb_define_class_under(mod, "SSLError", rb_eStandardError);

  rb_define_singleton_method(mod, "check", raise_error, 0);
}
#endif