// Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <openssl/digest.h>

#include <string.h>

#include <openssl/blake2.h>
#include <openssl/bytestring.h>
#include <openssl/evp_errors.h>
#include <openssl/md4.h>
#include <openssl/md5.h>
#include <openssl/nid.h>
#include <openssl/obj.h>
#include <openssl/sha.h>
#include <openssl/span.h>

#include "../asn1/internal.h"
#include "../fipsmodule/digest/internal.h"
#include "../internal.h"


struct nid_to_digest {
  int nid;
  const EVP_MD *(*md_func)();
  const char *short_name;
  const char *long_name;
};

static const struct nid_to_digest nid_to_digest_mapping[] = {
    {NID_md4, EVP_md4, SN_md4, LN_md4},
    {NID_md5, EVP_md5, SN_md5, LN_md5},
    {NID_sha1, EVP_sha1, SN_sha1, LN_sha1},
    {NID_sha224, EVP_sha224, SN_sha224, LN_sha224},
    {NID_sha256, EVP_sha256, SN_sha256, LN_sha256},
    {NID_sha384, EVP_sha384, SN_sha384, LN_sha384},
    {NID_sha512, EVP_sha512, SN_sha512, LN_sha512},
    {NID_sha512_256, EVP_sha512_256, SN_sha512_256, LN_sha512_256},
    {NID_md5_sha1, EVP_md5_sha1, SN_md5_sha1, LN_md5_sha1},
    // As a remnant of signing |EVP_MD|s, OpenSSL returned the corresponding
    // hash function when given a signature OID. To avoid unintended lax parsing
    // of hash OIDs, this is no longer supported for lookup by OID or NID.
    // Node.js, however, exposes |EVP_get_digestbyname|'s full behavior to
    // consumers so we retain it there.
    {NID_undef, EVP_sha1, SN_dsaWithSHA, LN_dsaWithSHA},
    {NID_undef, EVP_sha1, SN_dsaWithSHA1, LN_dsaWithSHA1},
    {NID_undef, EVP_sha1, SN_ecdsa_with_SHA1, nullptr},
    {NID_undef, EVP_md5, SN_md5WithRSAEncryption, LN_md5WithRSAEncryption},
    {NID_undef, EVP_sha1, SN_sha1WithRSAEncryption, LN_sha1WithRSAEncryption},
    {NID_undef, EVP_sha224, SN_sha224WithRSAEncryption,
     LN_sha224WithRSAEncryption},
    {NID_undef, EVP_sha256, SN_sha256WithRSAEncryption,
     LN_sha256WithRSAEncryption},
    {NID_undef, EVP_sha384, SN_sha384WithRSAEncryption,
     LN_sha384WithRSAEncryption},
    {NID_undef, EVP_sha512, SN_sha512WithRSAEncryption,
     LN_sha512WithRSAEncryption},
};

const EVP_MD *EVP_get_digestbynid(int nid) {
  if (nid == NID_undef) {
    // Skip the |NID_undef| entries in |nid_to_digest_mapping|.
    return nullptr;
  }

  for (const auto &mapping : nid_to_digest_mapping) {
    if (mapping.nid == nid) {
      return mapping.md_func();
    }
  }

  return nullptr;
}

static const struct {
  uint8_t oid[9];
  uint8_t oid_len;
  int nid;
} kMDOIDs[] = {
    // 1.2.840.113549.2.4
    {{0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x04}, 8, NID_md4},
    // 1.2.840.113549.2.5
    {{0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05}, 8, NID_md5},
    // 1.3.14.3.2.26
    {{0x2b, 0x0e, 0x03, 0x02, 0x1a}, 5, NID_sha1},
    // 2.16.840.1.101.3.4.2.1
    {{0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01}, 9, NID_sha256},
    // 2.16.840.1.101.3.4.2.2
    {{0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02}, 9, NID_sha384},
    // 2.16.840.1.101.3.4.2.3
    {{0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03}, 9, NID_sha512},
    // 2.16.840.1.101.3.4.2.4
    {{0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04}, 9, NID_sha224},
};

static int cbs_to_digest_nid(const CBS *cbs) {
  for (const auto &md : kMDOIDs) {
    if (bssl::Span<const uint8_t>(*cbs) ==
        bssl::Span(md.oid).first(md.oid_len)) {
      return md.nid;
    }
  }
  return NID_undef;
}

const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *obj) {
  int nid = obj->nid;
  if (nid == NID_undef) {
    // Handle objects with no saved NID. Note we don't use |OBJ_obj2nid| here to
    // avoid pulling in the OID table.
    CBS cbs;
    CBS_init(&cbs, OBJ_get0_data(obj), OBJ_length(obj));
    nid = cbs_to_digest_nid(&cbs);
  }

  return nid == NID_undef ? nullptr : EVP_get_digestbynid(nid);
}

int EVP_parse_digest_algorithm_nid(CBS *cbs) {
  CBS algorithm, oid;
  if (!CBS_get_asn1(cbs, &algorithm, CBS_ASN1_SEQUENCE) ||
      !CBS_get_asn1(&algorithm, &oid, CBS_ASN1_OBJECT)) {
    OPENSSL_PUT_ERROR(DIGEST, DIGEST_R_DECODE_ERROR);
    return NID_undef;
  }

  int ret = cbs_to_digest_nid(&oid);
  if (ret == NID_undef) {
    OPENSSL_PUT_ERROR(DIGEST, DIGEST_R_UNKNOWN_HASH);
    return NID_undef;
  }

  // The parameters, if present, must be NULL. Historically, whether the NULL
  // was included or omitted was not well-specified. When parsing an
  // AlgorithmIdentifier, we allow both. (Note this code is not used when
  // verifying RSASSA-PKCS1-v1_5 signatures.)
  if (CBS_len(&algorithm) > 0) {
    CBS param;
    if (!CBS_get_asn1(&algorithm, &param, CBS_ASN1_NULL) ||
        CBS_len(&param) != 0 ||  //
        CBS_len(&algorithm) != 0) {
      OPENSSL_PUT_ERROR(DIGEST, DIGEST_R_DECODE_ERROR);
      return NID_undef;
    }
  }

  return ret;
}

const EVP_MD *EVP_parse_digest_algorithm(CBS *cbs) {
  int nid = EVP_parse_digest_algorithm_nid(cbs);
  if (nid == NID_undef) {
    return nullptr;
  }
  return EVP_get_digestbynid(nid);
}

static int marshal_digest_algorithm(CBB *cbb, const EVP_MD *md,
                                    bool with_null) {
  CBB algorithm, oid, null;
  if (!CBB_add_asn1(cbb, &algorithm, CBS_ASN1_SEQUENCE) ||
      !CBB_add_asn1(&algorithm, &oid, CBS_ASN1_OBJECT)) {
    return 0;
  }

  bool found = false;
  int nid = EVP_MD_type(md);
  for (const auto &mdoid : kMDOIDs) {
    if (nid == mdoid.nid) {
      if (!CBB_add_bytes(&oid, mdoid.oid, mdoid.oid_len)) {
        return 0;
      }
      found = true;
      break;
    }
  }

  if (!found) {
    OPENSSL_PUT_ERROR(DIGEST, DIGEST_R_UNKNOWN_HASH);
    return 0;
  }

  if ((with_null && !CBB_add_asn1(&algorithm, &null, CBS_ASN1_NULL)) ||  //
      !CBB_flush(cbb)) {
    return 0;
  }

  return 1;
}

int EVP_marshal_digest_algorithm(CBB *cbb, const EVP_MD *md) {
  return marshal_digest_algorithm(cbb, md, /*with_null=*/true);
}

int EVP_marshal_digest_algorithm_no_params(CBB *cbb, const EVP_MD *md) {
  return marshal_digest_algorithm(cbb, md, /*with_null=*/false);
}

const EVP_MD *EVP_get_digestbyname(const char *name) {
  for (const auto &mapping : nid_to_digest_mapping) {
    const char *short_name = mapping.short_name;
    const char *long_name = mapping.long_name;
    if ((short_name && strcmp(short_name, name) == 0) ||
        (long_name && strcmp(long_name, name) == 0)) {
      return mapping.md_func();
    }
  }

  return nullptr;
}

EVP_MD *EVP_MD_fetch(OSSL_LIB_CTX *libctx, const char *name,
                     const char *propq) {
  EVP_MD *ret = const_cast<EVP_MD *>(EVP_get_digestbyname(name));
  if (ret == nullptr) {
    OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_ALGORITHM);
  }
  return ret;
}

int EVP_MD_up_ref(EVP_MD *md) { return 1; }

void EVP_MD_free(EVP_MD *md) {}

int EVP_Q_digest(OSSL_LIB_CTX *libctx, const char *name, const char *propq,
                 const void *in, size_t in_len, uint8_t *out, size_t *out_len) {
  const EVP_MD *md = EVP_MD_fetch(libctx, name, propq);
  if (md == nullptr) {
    return 0;
  }
  unsigned len_u;
  if (!EVP_Digest(in, in_len, out, &len_u, md, nullptr)) {
    return 0;
  }
  *out_len = len_u;
  return 1;
}

static void blake2b256_init(EVP_MD_CTX *ctx) {
  BLAKE2B256_Init(reinterpret_cast<BLAKE2B_CTX *>(ctx->md_data));
}

static void blake2b256_update(EVP_MD_CTX *ctx, const void *data, size_t len) {
  BLAKE2B256_Update(reinterpret_cast<BLAKE2B_CTX *>(ctx->md_data), data, len);
}

static void blake2b256_final(EVP_MD_CTX *ctx, uint8_t *md) {
  BLAKE2B256_Final(md, reinterpret_cast<BLAKE2B_CTX *>(ctx->md_data));
}

static const EVP_MD evp_md_blake2b256 = {
    NID_undef,       BLAKE2B256_DIGEST_LENGTH, 0,
    blake2b256_init, blake2b256_update,        blake2b256_final,
    BLAKE2B_CBLOCK,  sizeof(BLAKE2B_CTX),
};

const EVP_MD *EVP_blake2b256() { return &evp_md_blake2b256; }

static_assert(sizeof(BLAKE2B_CTX) <= EVP_MAX_MD_DATA_SIZE);


static void md4_init(EVP_MD_CTX *ctx) {
  BSSL_CHECK(MD4_Init(reinterpret_cast<MD4_CTX *>(ctx->md_data)));
}

static void md4_update(EVP_MD_CTX *ctx, const void *data, size_t count) {
  BSSL_CHECK(
      MD4_Update(reinterpret_cast<MD4_CTX *>(ctx->md_data), data, count));
}

static void md4_final(EVP_MD_CTX *ctx, uint8_t *out) {
  BSSL_CHECK(MD4_Final(out, reinterpret_cast<MD4_CTX *>(ctx->md_data)));
}

static const EVP_MD evp_md_md4 = {
    NID_md4,            //
    MD4_DIGEST_LENGTH,  //
    0,
    md4_init,
    md4_update,
    md4_final,
    64,
    sizeof(MD4_CTX),
};

const EVP_MD *EVP_md4() { return &evp_md_md4; }

static_assert(sizeof(MD4_CTX) <= EVP_MAX_MD_DATA_SIZE);


static void md5_init(EVP_MD_CTX *ctx) {
  BSSL_CHECK(MD5_Init(reinterpret_cast<MD5_CTX *>(ctx->md_data)));
}

static void md5_update(EVP_MD_CTX *ctx, const void *data, size_t count) {
  BSSL_CHECK(
      MD5_Update(reinterpret_cast<MD5_CTX *>(ctx->md_data), data, count));
}

static void md5_final(EVP_MD_CTX *ctx, uint8_t *out) {
  BSSL_CHECK(MD5_Final(out, reinterpret_cast<MD5_CTX *>(ctx->md_data)));
}

static const EVP_MD evp_md_md5 = {
    NID_md5,    MD5_DIGEST_LENGTH, 0,  md5_init,
    md5_update, md5_final,         64, sizeof(MD5_CTX),
};

const EVP_MD *EVP_md5() { return &evp_md_md5; }

static_assert(sizeof(MD5_CTX) <= EVP_MAX_MD_DATA_SIZE);


typedef struct {
  MD5_CTX md5;
  SHA_CTX sha1;
} MD5_SHA1_CTX;

static void md5_sha1_init(EVP_MD_CTX *md_ctx) {
  MD5_SHA1_CTX *ctx = reinterpret_cast<MD5_SHA1_CTX *>(md_ctx->md_data);
  BSSL_CHECK(MD5_Init(&ctx->md5) && SHA1_Init(&ctx->sha1));
}

static void md5_sha1_update(EVP_MD_CTX *md_ctx, const void *data,
                            size_t count) {
  MD5_SHA1_CTX *ctx = reinterpret_cast<MD5_SHA1_CTX *>(md_ctx->md_data);
  BSSL_CHECK(MD5_Update(&ctx->md5, data, count) &&
             SHA1_Update(&ctx->sha1, data, count));
}

static void md5_sha1_final(EVP_MD_CTX *md_ctx, uint8_t *out) {
  MD5_SHA1_CTX *ctx = reinterpret_cast<MD5_SHA1_CTX *>(md_ctx->md_data);
  BSSL_CHECK(MD5_Final(out, &ctx->md5) &&
             SHA1_Final(out + MD5_DIGEST_LENGTH, &ctx->sha1));
}

const EVP_MD evp_md_md5_sha1 = {
    NID_md5_sha1,
    MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH,
    0,
    md5_sha1_init,
    md5_sha1_update,
    md5_sha1_final,
    64,
    sizeof(MD5_SHA1_CTX),
};

const EVP_MD *EVP_md5_sha1() { return &evp_md_md5_sha1; }

static_assert(sizeof(MD5_SHA1_CTX) <= EVP_MAX_MD_DATA_SIZE);