/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * SPDX-License-Identifier: MPL-2.0

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, you can obtain one at https://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

/*! \file */

#include <stdbool.h>

#include <openssl/err.h>

#include <openssl/evp.h>

#include <openssl/objects.h>

#include <openssl/x509.h>

#include <isc/mem.h>

#include <isc/result.h>

#include <isc/safe.h>

#include <isc/string.h>

#include <isc/util.h>

#include <dns/keyvalues.h>

#include "dst_internal.h"

#include "dst_openssl.h"

#include "dst_parse.h"

#include "openssl_shim.h"

#define DST_RET(a)        \

  {                 \

    ret = a;  \

    goto err; \

  }

#ifndef NID_ED25519

#error "Ed25519 group is not known (NID_ED25519)"

#endif /* ifndef NID_ED25519 */

#if HAVE_OPENSSL_ED448

#ifndef NID_ED448

#error "Ed448 group is not known (NID_ED448)"

#endif /* ifndef NID_ED448 */

#endif /* HAVE_OPENSSL_ED448 */

typedef struct eddsa_alginfo {

  int pkey_type, nid;

  unsigned int key_size, sig_size;

} eddsa_alginfo_t;

static const eddsa_alginfo_t *

openssleddsa_alg_info(unsigned int key_alg) {

  if (key_alg == DST_ALG_ED25519) {

    static const eddsa_alginfo_t ed25519_alginfo = {

      .pkey_type = EVP_PKEY_ED25519,

      .nid = NID_ED25519,

      .key_size = DNS_KEY_ED25519SIZE,

      .sig_size = DNS_SIG_ED25519SIZE,

    };

    return &ed25519_alginfo;

  }

#if HAVE_OPENSSL_ED448

  if (key_alg == DST_ALG_ED448) {

    static const eddsa_alginfo_t ed448_alginfo = {

      .pkey_type = EVP_PKEY_ED448,

      .nid = NID_ED448,

      .key_size = DNS_KEY_ED448SIZE,

      .sig_size = DNS_SIG_ED448SIZE,

    };

    return &ed448_alginfo;

  }

#endif /* HAVE_OPENSSL_ED448 */

  return NULL;

}

static isc_result_t

raw_key_to_ossl(const eddsa_alginfo_t *alginfo, int private,

    const unsigned char *key, size_t *key_len, EVP_PKEY **pkey) {

  isc_result_t ret;

  int pkey_type = alginfo->pkey_type;

  size_t len = alginfo->key_size;

  ret = (private ? DST_R_INVALIDPRIVATEKEY : DST_R_INVALIDPUBLICKEY);

  if (*key_len < len) {

    return ret;

  }

  if (private) {

    *pkey = EVP_PKEY_new_raw_private_key(pkey_type, NULL, key, len);

  } else {

    *pkey = EVP_PKEY_new_raw_public_key(pkey_type, NULL, key, len);

  }

  if (*pkey == NULL) {

    return dst__openssl_toresult(ret);

  }

  *key_len = len;

  return ISC_R_SUCCESS;

}

static isc_result_t

openssleddsa_fromlabel(dst_key_t *key, const char *label, const char *pin);

static isc_result_t

openssleddsa_createctx(dst_key_t *key, dst_context_t *dctx) {

  isc_buffer_t *buf = NULL;

  const eddsa_alginfo_t *alginfo =

    openssleddsa_alg_info(dctx->key->key_alg);

  UNUSED(key);

  REQUIRE(alginfo != NULL);

  isc_buffer_allocate(dctx->mctx, &buf, 64);

  dctx->ctxdata.generic = buf;

  return ISC_R_SUCCESS;

}

static void

openssleddsa_destroyctx(dst_context_t *dctx) {

  isc_buffer_t *buf = (isc_buffer_t *)dctx->ctxdata.generic;

  const eddsa_alginfo_t *alginfo =

    openssleddsa_alg_info(dctx->key->key_alg);

  REQUIRE(alginfo != NULL);

  if (buf != NULL) {

    isc_buffer_free(&buf);

  }

  dctx->ctxdata.generic = NULL;

}

static isc_result_t

openssleddsa_adddata(dst_context_t *dctx, const isc_region_t *data) {

  isc_buffer_t *buf = (isc_buffer_t *)dctx->ctxdata.generic;

  isc_buffer_t *nbuf = NULL;

  isc_region_t r;

  unsigned int length;

  isc_result_t result;

  const eddsa_alginfo_t *alginfo =

    openssleddsa_alg_info(dctx->key->key_alg);

  REQUIRE(alginfo != NULL);

  result = isc_buffer_copyregion(buf, data);

  if (result == ISC_R_SUCCESS) {

    return ISC_R_SUCCESS;

  }

  length = isc_buffer_length(buf) + data->length + 64;

  isc_buffer_allocate(dctx->mctx, &nbuf, length);

  isc_buffer_usedregion(buf, &r);

  (void)isc_buffer_copyregion(nbuf, &r);

  (void)isc_buffer_copyregion(nbuf, data);

  isc_buffer_free(&buf);

  dctx->ctxdata.generic = nbuf;

  return ISC_R_SUCCESS;

}

static isc_result_t

openssleddsa_sign(dst_context_t *dctx, isc_buffer_t *sig) {

  isc_result_t ret;

  dst_key_t *key = dctx->key;

  isc_region_t tbsreg;

  isc_region_t sigreg;

  EVP_PKEY *pkey = key->keydata.pkeypair.priv;

  EVP_MD_CTX *ctx = EVP_MD_CTX_new();

  isc_buffer_t *buf = (isc_buffer_t *)dctx->ctxdata.generic;

  const eddsa_alginfo_t *alginfo = openssleddsa_alg_info(key->key_alg);

  size_t siglen;

  REQUIRE(alginfo != NULL);

  if (ctx == NULL) {

    return ISC_R_NOMEMORY;

  }

  siglen = alginfo->sig_size;

  isc_buffer_availableregion(sig, &sigreg);

  if (sigreg.length < (unsigned int)siglen) {

    DST_RET(ISC_R_NOSPACE);

  }

  isc_buffer_usedregion(buf, &tbsreg);

  if (EVP_DigestSignInit(ctx, NULL, NULL, NULL, pkey) != 1) {

    DST_RET(dst__openssl_toresult3(

      dctx->category, "EVP_DigestSignInit", ISC_R_FAILURE));

  }

  if (EVP_DigestSign(ctx, sigreg.base, &siglen, tbsreg.base,

         tbsreg.length) != 1)

  {

    DST_RET(dst__openssl_toresult3(dctx->category, "EVP_DigestSign",

                 DST_R_SIGNFAILURE));

  }

  isc_buffer_add(sig, (unsigned int)siglen);

  ret = ISC_R_SUCCESS;

err:

  EVP_MD_CTX_free(ctx);

  isc_buffer_free(&buf);

  dctx->ctxdata.generic = NULL;

  return ret;

}

static isc_result_t

openssleddsa_verify(dst_context_t *dctx, const isc_region_t *sig) {

  isc_result_t ret;

  dst_key_t *key = dctx->key;

  int status;

  isc_region_t tbsreg;

  EVP_PKEY *pkey = key->keydata.pkeypair.pub;

  EVP_MD_CTX *ctx = EVP_MD_CTX_new();

  isc_buffer_t *buf = (isc_buffer_t *)dctx->ctxdata.generic;

  const eddsa_alginfo_t *alginfo = openssleddsa_alg_info(key->key_alg);

  REQUIRE(alginfo != NULL);

  if (ctx == NULL) {

    return dst__openssl_toresult(ISC_R_NOMEMORY);

  }

  if (sig->length != alginfo->sig_size) {

    DST_RET(DST_R_VERIFYFAILURE);

  }

  isc_buffer_usedregion(buf, &tbsreg);

  if (EVP_DigestVerifyInit(ctx, NULL, NULL, NULL, pkey) != 1) {

    DST_RET(dst__openssl_toresult3(

      dctx->category, "EVP_DigestVerifyInit", ISC_R_FAILURE));

  }

  status = EVP_DigestVerify(ctx, sig->base, sig->length, tbsreg.base,

          tbsreg.length);

  switch (status) {

  case 1:

    ret = ISC_R_SUCCESS;

    break;

  case 0:

    ret = dst__openssl_toresult(DST_R_VERIFYFAILURE);

    break;

  default:

    ret = dst__openssl_toresult3(dctx->category, "EVP_DigestVerify",

               DST_R_VERIFYFAILURE);

    break;

  }

err:

  EVP_MD_CTX_free(ctx);

  isc_buffer_free(&buf);

  dctx->ctxdata.generic = NULL;

  return ret;

}

static isc_result_t

openssleddsa_generate(dst_key_t *key, int unused, void (*callback)(int)) {

  isc_result_t ret;

  EVP_PKEY *pkey = NULL;

  EVP_PKEY_CTX *ctx = NULL;

  const eddsa_alginfo_t *alginfo = openssleddsa_alg_info(key->key_alg);

  int status;

  REQUIRE(alginfo != NULL);

  UNUSED(unused);

  UNUSED(callback);

  ctx = EVP_PKEY_CTX_new_id(alginfo->nid, NULL);

  if (ctx == NULL) {

    return dst__openssl_toresult2("EVP_PKEY_CTX_new_id",

                DST_R_OPENSSLFAILURE);

  }

  status = EVP_PKEY_keygen_init(ctx);

  if (status != 1) {

    DST_RET(dst__openssl_toresult2("EVP_PKEY_keygen_init",

                 DST_R_OPENSSLFAILURE));

  }

  status = EVP_PKEY_keygen(ctx, &pkey);

  if (status != 1) {

    DST_RET(dst__openssl_toresult2("EVP_PKEY_keygen",

                 DST_R_OPENSSLFAILURE));

  }

  key->key_size = alginfo->key_size * 8;

  key->keydata.pkeypair.priv = pkey;

  key->keydata.pkeypair.pub = pkey;

  ret = ISC_R_SUCCESS;

err:

  EVP_PKEY_CTX_free(ctx);

  return ret;

}

static isc_result_t

openssleddsa_todns(const dst_key_t *key, isc_buffer_t *data) {

  const eddsa_alginfo_t *alginfo = openssleddsa_alg_info(key->key_alg);

  EVP_PKEY *pkey = key->keydata.pkeypair.pub;

  isc_region_t r;

  size_t len;

  REQUIRE(pkey != NULL);

  REQUIRE(alginfo != NULL);

  len = alginfo->key_size;

  isc_buffer_availableregion(data, &r);

  if (r.length < len) {

    return ISC_R_NOSPACE;

  }

  if (EVP_PKEY_get_raw_public_key(pkey, r.base, &len) != 1) {

    return dst__openssl_toresult(ISC_R_FAILURE);

  }

  isc_buffer_add(data, len);

  return ISC_R_SUCCESS;

}

static isc_result_t

openssleddsa_fromdns(dst_key_t *key, isc_buffer_t *data) {

  const eddsa_alginfo_t *alginfo = openssleddsa_alg_info(key->key_alg);

  isc_result_t ret;

  isc_region_t r;

  size_t len;

  EVP_PKEY *pkey = NULL;

  REQUIRE(alginfo != NULL);

  isc_buffer_remainingregion(data, &r);

  if (r.length == 0) {

    return ISC_R_SUCCESS;

  }

  len = r.length;

  ret = raw_key_to_ossl(alginfo, 0, r.base, &len, &pkey);

  if (ret != ISC_R_SUCCESS) {

    return ret;

  }

  isc_buffer_forward(data, len);

  key->keydata.pkeypair.pub = pkey;

  key->key_size = len * 8;

  return ISC_R_SUCCESS;

}

static isc_result_t

openssleddsa_tofile(const dst_key_t *key, const char *directory) {

  const eddsa_alginfo_t *alginfo = openssleddsa_alg_info(key->key_alg);

  isc_result_t ret;

  dst_private_t priv;

  unsigned char *buf = NULL;

  size_t len;

  int i;

  REQUIRE(alginfo != NULL);

  if (key->keydata.pkeypair.pub == NULL) {

    return DST_R_NULLKEY;

  }

  if (key->external) {

    priv.nelements = 0;

    return dst__privstruct_writefile(key, &priv, directory);

  }

  i = 0;

  if (dst__openssl_keypair_isprivate(key)) {

    len = alginfo->key_size;

    buf = isc_mem_get(key->mctx, len);

    if (EVP_PKEY_get_raw_private_key(key->keydata.pkeypair.priv,

             buf, &len) != 1)

    {

      DST_RET(dst__openssl_toresult(ISC_R_FAILURE));

    }

    priv.elements[i].tag = TAG_EDDSA_PRIVATEKEY;

    priv.elements[i].length = len;

    priv.elements[i].data = buf;

    i++;

  }

  if (key->label != NULL) {

    priv.elements[i].tag = TAG_EDDSA_LABEL;

    priv.elements[i].length = (unsigned short)strlen(key->label) +

            1;

    priv.elements[i].data = (unsigned char *)key->label;

    i++;

  }

  priv.nelements = i;

  ret = dst__privstruct_writefile(key, &priv, directory);

err:

  if (buf != NULL) {

    isc_mem_put(key->mctx, buf, len);

  }

  return ret;

}

static isc_result_t

openssleddsa_parse(dst_key_t *key, isc_lex_t *lexer, dst_key_t *pub) {

  const eddsa_alginfo_t *alginfo = openssleddsa_alg_info(key->key_alg);

  dst_private_t priv;

  isc_result_t ret;

  int i, privkey_index = -1;

  const char *label = NULL;

  EVP_PKEY *pkey = NULL;

  size_t len;

  isc_mem_t *mctx = key->mctx;

  REQUIRE(alginfo != NULL);

  /* read private key file */

  ret = dst__privstruct_parse(key, DST_ALG_ED25519, lexer, mctx, &priv);

  if (ret != ISC_R_SUCCESS) {

    goto err;

  }

  if (key->external) {

    if (priv.nelements != 0) {

      DST_RET(DST_R_INVALIDPRIVATEKEY);

    }

    if (pub == NULL) {

      DST_RET(DST_R_INVALIDPRIVATEKEY);

    }

    key->keydata.pkeypair.priv = pub->keydata.pkeypair.priv;

    key->keydata.pkeypair.pub = pub->keydata.pkeypair.pub;

    pub->keydata.pkeypair.priv = NULL;

    pub->keydata.pkeypair.pub = NULL;

    DST_RET(ISC_R_SUCCESS);

  }

  for (i = 0; i < priv.nelements; i++) {

    switch (priv.elements[i].tag) {

    case TAG_EDDSA_ENGINE:

      /* The Engine: tag is explicitly ignored */

      break;

    case TAG_EDDSA_LABEL:

      label = (char *)priv.elements[i].data;

      break;

    case TAG_EDDSA_PRIVATEKEY:

      privkey_index = i;

      break;

    default:

      break;

    }

  }

  if (label != NULL) {

    ret = openssleddsa_fromlabel(key, label, NULL);

    if (ret != ISC_R_SUCCESS) {

      goto err;

    }

    /* Check that the public component matches if given */

    if (pub != NULL && EVP_PKEY_eq(key->keydata.pkeypair.pub,

                 pub->keydata.pkeypair.pub) != 1)

    {

      DST_RET(DST_R_INVALIDPRIVATEKEY);

    }

    DST_RET(ISC_R_SUCCESS);

  }

  if (privkey_index < 0) {

    DST_RET(DST_R_INVALIDPRIVATEKEY);

  }

  len = priv.elements[privkey_index].length;

  ret = raw_key_to_ossl(alginfo, 1, priv.elements[privkey_index].data,

            &len, &pkey);

  if (ret != ISC_R_SUCCESS) {

    goto err;

  }

  /* Check that the public component matches if given */

  if (pub != NULL && EVP_PKEY_eq(pkey, pub->keydata.pkeypair.pub) != 1) {

    DST_RET(DST_R_INVALIDPRIVATEKEY);

  }

  key->keydata.pkeypair.priv = pkey;

  key->keydata.pkeypair.pub = pkey;

  key->key_size = len * 8;

  pkey = NULL;

  ret = ISC_R_SUCCESS;

err:

  EVP_PKEY_free(pkey);

  dst__privstruct_free(&priv, mctx);

  isc_safe_memwipe(&priv, sizeof(priv));

  return ret;

}

static isc_result_t

openssleddsa_fromlabel(dst_key_t *key, const char *label, const char *pin) {

  const eddsa_alginfo_t *alginfo = openssleddsa_alg_info(key->key_alg);

  EVP_PKEY *privpkey = NULL, *pubpkey = NULL;

  isc_result_t ret;

  REQUIRE(alginfo != NULL);

  UNUSED(pin);

  ret = dst__openssl_fromlabel(alginfo->pkey_type, label, pin, &pubpkey,

             &privpkey);

  if (ret != ISC_R_SUCCESS) {

    goto err;

  }

  key->label = isc_mem_strdup(key->mctx, label);

  key->key_size = EVP_PKEY_bits(privpkey);

  key->keydata.pkeypair.priv = privpkey;

  key->keydata.pkeypair.pub = pubpkey;

  privpkey = NULL;

  pubpkey = NULL;

err:

  EVP_PKEY_free(privpkey);

  EVP_PKEY_free(pubpkey);

  return ret;

}

static dst_func_t openssleddsa_functions = {

  .createctx = openssleddsa_createctx,

  .destroyctx = openssleddsa_destroyctx,

  .adddata = openssleddsa_adddata,

  .sign = openssleddsa_sign,

  .verify = openssleddsa_verify,

  .compare = dst__openssl_keypair_compare,

  .generate = openssleddsa_generate,

  .isprivate = dst__openssl_keypair_isprivate,

  .destroy = dst__openssl_keypair_destroy,

  .todns = openssleddsa_todns,

  .fromdns = openssleddsa_fromdns,

  .tofile = openssleddsa_tofile,

  .parse = openssleddsa_parse,

  .fromlabel = openssleddsa_fromlabel,

};

/*

 * The test vectors below where generated by util/gen-eddsa-vectors.c

 */

#if HAVE_OPENSSL_ED448

static unsigned char ed448_pub[] =

  "\x0a\x19\x36\xf0\x4c\x2d\xc1\xfe\xbe\xdc\xfa\xf6\xeb\xd2\x8f\x3b\x04"

  "\x14\x2e\x88\xc6\xb5\xdc\xe8\x2a\xc6\xb9\x7c\xa8\x22\xe8\x36\xfb\x06"

  "\x55\xa3\x3c\xdb\x9d\x68\x59\x7e\xa9\x5f\x93\x96\x87\x83\x28\xce\xdd"

  "\x12\xc9\xb8\x78\x02\x80";

static unsigned char ed448_sig[] =

  "\x7e\xec\x4e\x11\xd9\x79\x89\xd2\xe2\x85\x7a\x1c\xd7\x36\xe8\x24\x1f"

  "\x90\xa0\x9c\x84\xfb\x51\xcd\xdc\xfd\x05\xcd\x8c\x08\x51\x05\x18\xc8"

  "\x85\xb2\x28\x00\xea\xfe\x10\x46\xad\x52\xe6\xe9\x62\x35\x3b\x2a\x14"

  "\x8b\xe7\xf0\x66\x5f\x00\x66\x3c\xa1\x4d\x03\x95\xcc\x73\xfc\xf2\x40"

  "\x4b\x67\x85\x5b\x9f\xa9\x87\xb6\xbb\xa3\x9d\x73\x9f\xcb\x4e\x2c\xd2"

  "\x46\xc7\x84\xd3\x7d\x94\x32\x30\x27\xb0\xa7\xf6\x6d\xf4\x77\xe8\xf5"

  "\xb4\xee\x3f\x0e\x2b\x35\xdd\x5a\x35\xfe\x35\x00";

#endif

static unsigned char ed25519_pub[] =

  "\x66\x5c\x21\x59\xe3\xa0\x6e\xa3\x7d\x82\x7c\xf1\xe7\xa3\xdd\xaf\xd1"

  "\x6d\x92\x81\xfb\x09\x0c\x7c\xfe\x6d\xf8\x87\x24\x7e\x6e\x25";

static unsigned char ed25519_sig[] =

  "\x26\x70\x5c\xc1\x85\xb6\x5e\x65\xe5\xa7\xd5\x85\x63\xc9\x1d\x45\x56"

  "\x38\xa3\x9c\xa3\x42\x4d\xc8\x89\xff\x84\xea\x2c\xa8\x8b\xfa\x2f\xab"

  "\x75\x7c\x68\x95\xfd\xdf\x62\x60\x4e\x4d\x10\xf8\x3c\xae\xcf\x18\x93"

  "\x90\x05\xa4\x54\x38\x45\x2f\x81\x71\x1e\x0f\x46\x04";

static isc_result_t

check_algorithm(unsigned char algorithm) {

  EVP_MD_CTX *evp_md_ctx = EVP_MD_CTX_create();

  EVP_PKEY *pkey = NULL;

  const eddsa_alginfo_t *alginfo = NULL;

  const unsigned char *key = NULL;

  const unsigned char *sig = NULL;

  const unsigned char test[] = "test";

  isc_result_t ret = ISC_R_SUCCESS;

  size_t key_len, sig_len;

  if (evp_md_ctx == NULL) {

    DST_RET(ISC_R_NOMEMORY);

  }

  switch (algorithm) {

#if HAVE_OPENSSL_ED448

  case DST_ALG_ED448:

    sig = ed448_sig;

    sig_len = sizeof(ed448_sig) - 1;

    key = ed448_pub;

    key_len = sizeof(ed448_pub) - 1;

    alginfo = openssleddsa_alg_info(algorithm);

    break;

#endif /* HAVE_OPENSSL_ED448 */

  case DST_ALG_ED25519:

    sig = ed25519_sig;

    sig_len = sizeof(ed25519_sig) - 1;

    key = ed25519_pub;

    key_len = sizeof(ed25519_pub) - 1;

    alginfo = openssleddsa_alg_info(algorithm);

    break;

  default:

    DST_RET(ISC_R_NOTIMPLEMENTED);

  }

  INSIST(alginfo != NULL);

  ret = raw_key_to_ossl(alginfo, 0, key, &key_len, &pkey);

  if (ret != ISC_R_SUCCESS) {

    goto err;

  }

  /*

   * Check that we can verify the signature.

   */

  if (EVP_DigestVerifyInit(evp_md_ctx, NULL, NULL, NULL, pkey) != 1 ||

      EVP_DigestVerify(evp_md_ctx, sig, sig_len, test,

           sizeof(test) - 1) != 1)

  {

    DST_RET(ISC_R_NOTIMPLEMENTED);

  }

err:

  if (pkey != NULL) {

    EVP_PKEY_free(pkey);

  }

  if (evp_md_ctx != NULL) {

    EVP_MD_CTX_destroy(evp_md_ctx);

  }

  ERR_clear_error();

  return ret;

}

void

dst__openssleddsa_init(dst_func_t **funcp, unsigned char algorithm) {

  REQUIRE(funcp != NULL);

  if (*funcp == NULL) {

    if (check_algorithm(algorithm) == ISC_R_SUCCESS) {

      *funcp = &openssleddsa_functions;

    }

  }

}