text: /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   *
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   *
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   *
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.] */
  
  #include <openssl/ssl.h>
  
  #include <assert.h>
  #include <limits.h>
  
  #include <openssl/ec.h>
  #include <openssl/ec_key.h>
  #include <openssl/err.h>
  #include <openssl/evp.h>
  #include <openssl/mem.h>
  
  #include "internal.h"
  #include "../crypto/internal.h"
  
  
  namespace bssl {
  
  int ssl_is_key_type_supported(int key_type) {
    return key_type == EVP_PKEY_RSA || key_type == EVP_PKEY_EC ||
           key_type == EVP_PKEY_ED25519;
  }
  
  static int ssl_set_pkey(CERT *cert, EVP_PKEY *pkey) {
    if (!ssl_is_key_type_supported(pkey->type)) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_CERTIFICATE_TYPE);
      return 0;
    }
  
    if (cert->chain != NULL &&
        sk_CRYPTO_BUFFER_value(cert->chain, 0) != NULL &&
        // Sanity-check that the private key and the certificate match.
        !ssl_cert_check_private_key(cert, pkey)) {
      return 0;
    }
  
    EVP_PKEY_free(cert->privatekey);
    EVP_PKEY_up_ref(pkey);
    cert->privatekey = pkey;
  
    return 1;
  }
  
  typedef struct {
    uint16_t sigalg;
    int pkey_type;
    int curve;
    const EVP_MD *(*digest_func)(void);
    char is_rsa_pss;
  } SSL_SIGNATURE_ALGORITHM;
  
  static const SSL_SIGNATURE_ALGORITHM kSignatureAlgorithms[] = {
      {SSL_SIGN_RSA_PKCS1_MD5_SHA1, EVP_PKEY_RSA, NID_undef, &EVP_md5_sha1, 0},
      {SSL_SIGN_RSA_PKCS1_SHA1, EVP_PKEY_RSA, NID_undef, &EVP_sha1, 0},
      {SSL_SIGN_RSA_PKCS1_SHA256, EVP_PKEY_RSA, NID_undef, &EVP_sha256, 0},
      {SSL_SIGN_RSA_PKCS1_SHA384, EVP_PKEY_RSA, NID_undef, &EVP_sha384, 0},
      {SSL_SIGN_RSA_PKCS1_SHA512, EVP_PKEY_RSA, NID_undef, &EVP_sha512, 0},
  
      {SSL_SIGN_RSA_PSS_SHA256, EVP_PKEY_RSA, NID_undef, &EVP_sha256, 1},
      {SSL_SIGN_RSA_PSS_SHA384, EVP_PKEY_RSA, NID_undef, &EVP_sha384, 1},
      {SSL_SIGN_RSA_PSS_SHA512, EVP_PKEY_RSA, NID_undef, &EVP_sha512, 1},
  
      {SSL_SIGN_ECDSA_SHA1, EVP_PKEY_EC, NID_undef, &EVP_sha1, 0},
      {SSL_SIGN_ECDSA_SECP256R1_SHA256, EVP_PKEY_EC, NID_X9_62_prime256v1,
       &EVP_sha256, 0},
      {SSL_SIGN_ECDSA_SECP384R1_SHA384, EVP_PKEY_EC, NID_secp384r1, &EVP_sha384,
       0},
      {SSL_SIGN_ECDSA_SECP521R1_SHA512, EVP_PKEY_EC, NID_secp521r1, &EVP_sha512,
       0},
  
      {SSL_SIGN_ED25519, EVP_PKEY_ED25519, NID_undef, NULL, 0},
  };
  
  static const SSL_SIGNATURE_ALGORITHM *get_signature_algorithm(uint16_t sigalg) {
    for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kSignatureAlgorithms); i++) {
      if (kSignatureAlgorithms[i].sigalg == sigalg) {
        return &kSignatureAlgorithms[i];
      }
    }
    return NULL;
  }
  
  int ssl_has_private_key(const SSL *ssl) {
    return ssl->cert->privatekey != NULL || ssl->cert->key_method != NULL;
  }
  
  static int pkey_supports_algorithm(const SSL *ssl, EVP_PKEY *pkey,
                                     uint16_t sigalg) {
    const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
    if (alg == NULL ||
        EVP_PKEY_id(pkey) != alg->pkey_type) {
      return 0;
    }
  
    if (ssl3_protocol_version(ssl) >= TLS1_3_VERSION) {
      // RSA keys may only be used with RSA-PSS.
      if (alg->pkey_type == EVP_PKEY_RSA && !alg->is_rsa_pss) {
        return 0;
      }
  
      // EC keys have a curve requirement.
      if (alg->pkey_type == EVP_PKEY_EC &&
          (alg->curve == NID_undef ||
           EC_GROUP_get_curve_name(
               EC_KEY_get0_group(EVP_PKEY_get0_EC_KEY(pkey))) != alg->curve)) {
        return 0;
      }
    }
  
    return 1;
  }
  
  static int setup_ctx(SSL *ssl, EVP_MD_CTX *ctx, EVP_PKEY *pkey, uint16_t sigalg,
                       int is_verify) {
    if (!pkey_supports_algorithm(ssl, pkey, sigalg)) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_SIGNATURE_TYPE);
      return 0;
    }
  
    const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
    const EVP_MD *digest = alg->digest_func != NULL ? alg->digest_func() : NULL;
    EVP_PKEY_CTX *pctx;
    if (is_verify) {
      if (!EVP_DigestVerifyInit(ctx, &pctx, digest, NULL, pkey)) {
        return 0;
      }
    } else if (!EVP_DigestSignInit(ctx, &pctx, digest, NULL, pkey)) {
      return 0;
    }
  
    if (alg->is_rsa_pss) {
      if (!EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PSS_PADDING) ||
          !EVP_PKEY_CTX_set_rsa_pss_saltlen(pctx, -1 /* salt len = hash len */)) {
        return 0;
      }
    }
  
    return 1;
  }
  
  static int legacy_sign_digest_supported(const SSL_SIGNATURE_ALGORITHM *alg) {
    return (alg->pkey_type == EVP_PKEY_EC || alg->pkey_type == EVP_PKEY_RSA) &&
           !alg->is_rsa_pss;
  }
  
  static enum ssl_private_key_result_t legacy_sign(
      SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out, uint16_t sigalg,
      const uint8_t *in, size_t in_len) {
    // TODO(davidben): Remove support for |sign_digest|-only
    // |SSL_PRIVATE_KEY_METHOD|s.
    const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
    if (alg == NULL || !legacy_sign_digest_supported(alg)) {
      OPENSSL_PUT_ERROR(SSL, SSL_R_UNSUPPORTED_PROTOCOL_FOR_CUSTOM_KEY);
      return ssl_private_key_failure;
    }
  
    const EVP_MD *md = alg->digest_func();
    uint8_t hash[EVP_MAX_MD_SIZE];
    unsigned hash_len;
    if (!EVP_Digest(in, in_len, hash, &hash_len, md, NULL)) {
      return ssl_private_key_failure;
    }
  
    return ssl->cert->key_method->sign_digest(ssl, out, out_len, max_out, md,
                                              hash, hash_len);
  }
  
  enum ssl_private_key_result_t ssl_private_key_sign(
      SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len, size_t max_out,
      uint16_t sigalg, const uint8_t *in, size_t in_len) {
    SSL *const ssl = hs->ssl;
    if (ssl->cert->key_method != NULL) {
      enum ssl_private_key_result_t ret;
      if (hs->pending_private_key_op) {
        ret = ssl->cert->key_method->complete(ssl, out, out_len, max_out);
      } else {
        ret = (ssl->cert->key_method->sign != NULL
                   ? ssl->cert->key_method->sign
                   : legacy_sign)(ssl, out, out_len, max_out, sigalg, in, in_len);
      }
      hs->pending_private_key_op = ret == ssl_private_key_retry;
      return ret;
    }
  
    *out_len = max_out;
    ScopedEVP_MD_CTX ctx;
    if (!setup_ctx(ssl, ctx.get(), ssl->cert->privatekey, sigalg, 0 /* sign */) ||
        !EVP_DigestSign(ctx.get(), out, out_len, in, in_len)) {
      return ssl_private_key_failure;
    }
    return ssl_private_key_success;
  }
  
  int ssl_public_key_verify(SSL *ssl, const uint8_t *signature,
                            size_t signature_len, uint16_t sigalg, EVP_PKEY *pkey,
                            const uint8_t *in, size_t in_len) {
    ScopedEVP_MD_CTX ctx;
    return setup_ctx(ssl, ctx.get(), pkey, sigalg, 1 /* verify */) &&
           EVP_DigestVerify(ctx.get(), signature, signature_len, in, in_len);
  }
  
  enum ssl_private_key_result_t ssl_private_key_decrypt(
      SSL_HANDSHAKE *hs, uint8_t *out, size_t *out_len, size_t max_out,
      const uint8_t *in, size_t in_len) {
    SSL *const ssl = hs->ssl;
    if (ssl->cert->key_method != NULL) {
      enum ssl_private_key_result_t ret;
      if (hs->pending_private_key_op) {
        ret = ssl->cert->key_method->complete(ssl, out, out_len, max_out);
      } else {
        ret = ssl->cert->key_method->decrypt(ssl, out, out_len, max_out, in,
                                             in_len);
      }
      hs->pending_private_key_op = ret == ssl_private_key_retry;
      return ret;
    }
  
    RSA *rsa = EVP_PKEY_get0_RSA(ssl->cert->privatekey);
    if (rsa == NULL) {
      // Decrypt operations are only supported for RSA keys.
      OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
      return ssl_private_key_failure;
    }
  
    // Decrypt with no padding. PKCS#1 padding will be removed as part of the
    // timing-sensitive code by the caller.
    if (!RSA_decrypt(rsa, out_len, out, max_out, in, in_len, RSA_NO_PADDING)) {
      return ssl_private_key_failure;
    }
    return ssl_private_key_success;
  }
  
  int ssl_private_key_supports_signature_algorithm(SSL_HANDSHAKE *hs,
                                                   uint16_t sigalg) {
    SSL *const ssl = hs->ssl;
    if (!pkey_supports_algorithm(ssl, hs->local_pubkey.get(), sigalg)) {
      return 0;
    }
  
    // Ensure the RSA key is large enough for the hash. RSASSA-PSS requires that
    // emLen be at least hLen + sLen + 2. Both hLen and sLen are the size of the
    // hash in TLS. Reasonable RSA key sizes are large enough for the largest
    // defined RSASSA-PSS algorithm, but 1024-bit RSA is slightly too small for
    // SHA-512. 1024-bit RSA is sometimes used for test credentials, so check the
    // size so that we can fall back to another algorithm in that case.
    const SSL_SIGNATURE_ALGORITHM *alg = get_signature_algorithm(sigalg);
    if (alg->is_rsa_pss && (size_t)EVP_PKEY_size(hs->local_pubkey.get()) <
                               2 * EVP_MD_size(alg->digest_func()) + 2) {
      return 0;
    }
  
    // Newer algorithms require message-based private keys.
    // TODO(davidben): Remove this check when sign_digest is gone.
    if (ssl->cert->key_method != NULL &&
        ssl->cert->key_method->sign == NULL &&
        !legacy_sign_digest_supported(alg)) {
      return 0;
    }
  
    return 1;
  }
  
  }  // namespace bssl
  
  using namespace bssl;
  
  int SSL_use_RSAPrivateKey(SSL *ssl, RSA *rsa) {
    if (rsa == NULL) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
      return 0;
    }
  
    UniquePtr<EVP_PKEY> pkey(EVP_PKEY_new());
    if (!pkey ||
        !EVP_PKEY_set1_RSA(pkey.get(), rsa)) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_EVP_LIB);
      return 0;
    }
  
    return ssl_set_pkey(ssl->cert, pkey.get());
  }
  
  int SSL_use_RSAPrivateKey_ASN1(SSL *ssl, const uint8_t *der, size_t der_len) {
    UniquePtr<RSA> rsa(RSA_private_key_from_bytes(der, der_len));
    if (!rsa) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB);
      return 0;
    }
  
    return SSL_use_RSAPrivateKey(ssl, rsa.get());
  }
  
  int SSL_use_PrivateKey(SSL *ssl, EVP_PKEY *pkey) {
    if (pkey == NULL) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
      return 0;
    }
  
    return ssl_set_pkey(ssl->cert, pkey);
  }
  
  int SSL_use_PrivateKey_ASN1(int type, SSL *ssl, const uint8_t *der,
                              size_t der_len) {
    if (der_len > LONG_MAX) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
      return 0;
    }
  
    const uint8_t *p = der;
    UniquePtr<EVP_PKEY> pkey(d2i_PrivateKey(type, NULL, &p, (long)der_len));
    if (!pkey || p != der + der_len) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB);
      return 0;
    }
  
    return SSL_use_PrivateKey(ssl, pkey.get());
  }
  
  int SSL_CTX_use_RSAPrivateKey(SSL_CTX *ctx, RSA *rsa) {
    if (rsa == NULL) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
      return 0;
    }
  
    UniquePtr<EVP_PKEY> pkey(EVP_PKEY_new());
    if (!pkey ||
        !EVP_PKEY_set1_RSA(pkey.get(), rsa)) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_EVP_LIB);
      return 0;
    }
  
    return ssl_set_pkey(ctx->cert, pkey.get());
  }
  
  int SSL_CTX_use_RSAPrivateKey_ASN1(SSL_CTX *ctx, const uint8_t *der,
                                     size_t der_len) {
    UniquePtr<RSA> rsa(RSA_private_key_from_bytes(der, der_len));
    if (!rsa) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB);
      return 0;
    }
  
    return SSL_CTX_use_RSAPrivateKey(ctx, rsa.get());
  }
  
  int SSL_CTX_use_PrivateKey(SSL_CTX *ctx, EVP_PKEY *pkey) {
    if (pkey == NULL) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_PASSED_NULL_PARAMETER);
      return 0;
    }
  
    return ssl_set_pkey(ctx->cert, pkey);
  }
  
  int SSL_CTX_use_PrivateKey_ASN1(int type, SSL_CTX *ctx, const uint8_t *der,
                                  size_t der_len) {
    if (der_len > LONG_MAX) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
      return 0;
    }
  
    const uint8_t *p = der;
    UniquePtr<EVP_PKEY> pkey(d2i_PrivateKey(type, NULL, &p, (long)der_len));
    if (!pkey || p != der + der_len) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_ASN1_LIB);
      return 0;
    }
  
    return SSL_CTX_use_PrivateKey(ctx, pkey.get());
  }
  
  void SSL_set_private_key_method(SSL *ssl,
                                  const SSL_PRIVATE_KEY_METHOD *key_method) {
    ssl->cert->key_method = key_method;
  }
  
  void SSL_CTX_set_private_key_method(SSL_CTX *ctx,
                                      const SSL_PRIVATE_KEY_METHOD *key_method) {
    ctx->cert->key_method = key_method;
  }
  
  static int set_algorithm_prefs(uint16_t **out_prefs, size_t *out_num_prefs,
                                 const uint16_t *prefs, size_t num_prefs) {
    OPENSSL_free(*out_prefs);
  
    *out_num_prefs = 0;
    *out_prefs = (uint16_t *)BUF_memdup(prefs, num_prefs * sizeof(prefs[0]));
    if (*out_prefs == NULL) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
      return 0;
    }
    *out_num_prefs = num_prefs;
  
    return 1;
  }
  
  int SSL_CTX_set_signing_algorithm_prefs(SSL_CTX *ctx, const uint16_t *prefs,
                                          size_t num_prefs) {
    return set_algorithm_prefs(&ctx->cert->sigalgs, &ctx->cert->num_sigalgs,
                               prefs, num_prefs);
  }
  
  
  int SSL_set_signing_algorithm_prefs(SSL *ssl, const uint16_t *prefs,
                                      size_t num_prefs) {
    return set_algorithm_prefs(&ssl->cert->sigalgs, &ssl->cert->num_sigalgs,
                               prefs, num_prefs);
  }
  
  int SSL_CTX_set_verify_algorithm_prefs(SSL_CTX *ctx, const uint16_t *prefs,
                                         size_t num_prefs) {
    return set_algorithm_prefs(&ctx->verify_sigalgs, &ctx->num_verify_sigalgs,
                               prefs, num_prefs);
  }
  
  int SSL_set_private_key_digest_prefs(SSL *ssl, const int *digest_nids,
                                       size_t num_digests) {
    OPENSSL_free(ssl->cert->sigalgs);
  
    static_assert(sizeof(int) >= 2 * sizeof(uint16_t),
                  "sigalgs allocation may overflow");
  
    ssl->cert->num_sigalgs = 0;
    ssl->cert->sigalgs =
        (uint16_t *)OPENSSL_malloc(sizeof(uint16_t) * 2 * num_digests);
    if (ssl->cert->sigalgs == NULL) {
      OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
      return 0;
    }
  
    // Convert the digest list to a signature algorithms list.
    //
    // TODO(davidben): Replace this API with one that can express RSA-PSS, etc.
    for (size_t i = 0; i < num_digests; i++) {
      switch (digest_nids[i]) {
        case NID_sha1:
          ssl->cert->sigalgs[ssl->cert->num_sigalgs] = SSL_SIGN_RSA_PKCS1_SHA1;
          ssl->cert->sigalgs[ssl->cert->num_sigalgs + 1] = SSL_SIGN_ECDSA_SHA1;
          ssl->cert->num_sigalgs += 2;
          break;
        case NID_sha256:
          ssl->cert->sigalgs[ssl->cert->num_sigalgs] = SSL_SIGN_RSA_PKCS1_SHA256;
          ssl->cert->sigalgs[ssl->cert->num_sigalgs + 1] =
              SSL_SIGN_ECDSA_SECP256R1_SHA256;
          ssl->cert->num_sigalgs += 2;
          break;
        case NID_sha384:
          ssl->cert->sigalgs[ssl->cert->num_sigalgs] = SSL_SIGN_RSA_PKCS1_SHA384;
          ssl->cert->sigalgs[ssl->cert->num_sigalgs + 1] =
              SSL_SIGN_ECDSA_SECP384R1_SHA384;
          ssl->cert->num_sigalgs += 2;
          break;
        case NID_sha512:
          ssl->cert->sigalgs[ssl->cert->num_sigalgs] = SSL_SIGN_RSA_PKCS1_SHA512;
          ssl->cert->sigalgs[ssl->cert->num_sigalgs + 1] =
              SSL_SIGN_ECDSA_SECP521R1_SHA512;
          ssl->cert->num_sigalgs += 2;
          break;
      }
    }
  
    return 1;
  }
  