// Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) All rights reserved.
// SPDX-License-Identifier: Apache-2.0


#include <string.h>

#include <openssl/base.h>
#include <openssl/blake2.h>
#include <openssl/bytestring.h>
#include <openssl/digest.h>
#include <openssl/md4.h>
#include <openssl/obj.h>
#include <openssl/nid.h>

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


struct nid_to_digest {
  int nid;
  const EVP_MD* (*md_func)(void);
  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_ripemd160, EVP_ripemd160, SN_ripemd160, LN_ripemd160},
    {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_224, EVP_sha512_224, SN_sha512_224, LN_sha512_224},
    {NID_sha512_256, EVP_sha512_256, SN_sha512_256, LN_sha512_256},
    {NID_sha3_224, EVP_sha3_224, SN_sha3_224, LN_sha3_224},
    {NID_sha3_256, EVP_sha3_256, SN_sha3_256, LN_sha3_256},
    {NID_sha3_384, EVP_sha3_384, SN_sha3_384, LN_sha3_384},
    {NID_sha3_512, EVP_sha3_512, SN_sha3_512, LN_sha3_512},
    {NID_shake128, EVP_shake128, SN_shake128, LN_shake128},
    {NID_shake256, EVP_shake256, SN_shake256, LN_shake256},
    {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, NULL},
    {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 NULL;
  }

  for (unsigned i = 0; i < OPENSSL_ARRAY_SIZE(nid_to_digest_mapping); i++) {
    if (nid_to_digest_mapping[i].nid == nid) {
      return nid_to_digest_mapping[i].md_func();
    }
  }

  return NULL;
}

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 },
  // 1.3.36.3.2.1
  { {0x2b, 0x24, 0x03, 0x02, 0x01}, 5, NID_ripemd160 },
  // 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 const EVP_MD *cbs_to_md(const CBS *cbs) {
  for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kMDOIDs); i++) {
    if (CBS_len(cbs) == kMDOIDs[i].oid_len &&
        OPENSSL_memcmp(CBS_data(cbs), kMDOIDs[i].oid, kMDOIDs[i].oid_len) ==
            0) {
      return EVP_get_digestbynid(kMDOIDs[i].nid);
    }
  }

  return NULL;
}

const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *obj) {
  if(obj == NULL) {
    return NULL;
  }

  // Handle objects with no corresponding OID. Note we don't use |OBJ_obj2nid|
  // here to avoid pulling in the OID table.
  if (obj->nid != NID_undef) {
    return EVP_get_digestbynid(obj->nid);
  }

  CBS cbs;
  CBS_init(&cbs, OBJ_get0_data(obj), OBJ_length(obj));
  return cbs_to_md(&cbs);
}

const EVP_MD *EVP_parse_digest_algorithm(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 NULL;
  }

  const EVP_MD *ret = cbs_to_md(&oid);
  if (ret == NULL) {
    OPENSSL_PUT_ERROR(DIGEST, DIGEST_R_UNKNOWN_HASH);
    return NULL;
  }

  // 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 NULL;
    }
  }

  return ret;
}

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

  int found = 0;
  int nid = EVP_MD_type(md);
  for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kMDOIDs); i++) {
    if (nid == kMDOIDs[i].nid) {
      if (!CBB_add_bytes(&oid, kMDOIDs[i].oid, kMDOIDs[i].oid_len)) {
        return 0;
      }
      found = 1;
      break;
    }
  }

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

  // TODO(crbug.com/boringssl/710): Is this correct? See RFC 4055, section 2.1.
  if (!CBB_add_asn1(&algorithm, &null, CBS_ASN1_NULL) ||
      !CBB_flush(cbb)) {
    return 0;
  }

  return 1;
}

const EVP_MD *EVP_get_digestbyname(const char *name) {
  for (unsigned i = 0; i < OPENSSL_ARRAY_SIZE(nid_to_digest_mapping); i++) {
    const char *short_name = nid_to_digest_mapping[i].short_name;
    const char *long_name = nid_to_digest_mapping[i].long_name;
    if ((short_name && strcmp(short_name, name) == 0) ||
        (long_name && strcmp(long_name, name) == 0)) {
      return nid_to_digest_mapping[i].md_func();
    }
  }

  return NULL;
}

static void md4_init(EVP_MD_CTX *ctx) {
  AWSLC_ASSERT(MD4_Init(ctx->md_data));
}

static int md4_update(EVP_MD_CTX *ctx, const void *data, size_t count) {
  // MD4_Update always returns 1. Internally called function
  // |crypto_md32_update| is void. For test consistency and future
  // compatibility, the return value is propagated and returned
  return MD4_Update(ctx->md_data, data, count);
}

static void md4_final(EVP_MD_CTX *ctx, uint8_t *out) {
  AWSLC_ASSERT(MD4_Final(out, 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),
  NULL, // finalXOF
  NULL  // squeezeXOF
};

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

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

static int blake2b256_update(EVP_MD_CTX *ctx, const void *data, size_t len) {
  // BLAKE2B256_Update is a void function
  BLAKE2B256_Update(ctx->md_data, data, len);
  return 1;
}

static void blake2b256_final(EVP_MD_CTX *ctx, uint8_t *md) {
  BLAKE2B256_Final(md, 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),
  /*finalXOf*/   NULL,
  /*squeezeXOf*/ NULL
};

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

static void null_init(EVP_MD_CTX *ctx) {}

static int null_update(EVP_MD_CTX *ctx, const void *data, size_t count) { return 1;}

static void null_final(EVP_MD_CTX *ctx, unsigned char *md) {}

static const EVP_MD evp_md_null = {
  NID_undef,
  0,
  0,
  null_init,
  null_update,
  null_final,
  0,
  sizeof(EVP_MD_CTX),
  /*finalXOf*/   NULL,
  /*squeezeXOf*/ NULL
};

const EVP_MD *EVP_md_null(void) { return &evp_md_null; }