crypto/pkcs8/pkcs8.c - boringssl - Git at Google

 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 1999.
  */
 /* ====================================================================
  * Copyright (c) 1999 The OpenSSL Project.  All rights reserved.
  *
  * 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 above 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 acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  *
  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  *    endorse or promote products derived from this software without
  *    prior written permission. For written permission, please contact
  *    licensing@OpenSSL.org.
  *
  * 5. Products derived from this software may not be called "OpenSSL"
  *    nor may "OpenSSL" appear in their names without prior written
  *    permission of the OpenSSL Project.
  *
  * 6. Redistributions of any form whatsoever must retain the following
  *    acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  *
  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  * EXPRESSED 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 OpenSSL PROJECT OR
  * ITS 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.
  * ====================================================================
  *
  * This product includes cryptographic software written by Eric Young
  * (eay@cryptsoft.com).  This product includes software written by Tim
  * Hudson (tjh@cryptsoft.com). */

 #include <openssl/pkcs8.h>

 #include <assert.h>
 #include <limits.h>
 #include <string.h>

 #include <openssl/bytestring.h>
 #include <openssl/cipher.h>
 #include <openssl/digest.h>
 #include <openssl/err.h>
 #include <openssl/mem.h>
 #include <openssl/nid.h>
 #include <openssl/rand.h>

 #include "internal.h"
 #include "../bytestring/internal.h"
 #include "../internal.h"


 static int pkcs12_encode_password(const char *in, size_t in_len, uint8_t **out,
                                   size_t *out_len) {
   CBB cbb;
   if (!CBB_init(&cbb, in_len * 2)) {
     return 0;
   }

   // Convert the password to BMPString, or UCS-2. See
   // https://tools.ietf.org/html/rfc7292#appendix-B.1.
   CBS cbs;
   CBS_init(&cbs, (const uint8_t *)in, in_len);
   while (CBS_len(&cbs) != 0) {
     uint32_t c;
     if (!cbs_get_utf8(&cbs, &c) ||
         !cbb_add_ucs2_be(&cbb, c)) {
       OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_INVALID_CHARACTERS);
       goto err;
     }
   }

   // Terminate the result with a UCS-2 NUL.
   if (!cbb_add_ucs2_be(&cbb, 0) ||
       !CBB_finish(&cbb, out, out_len)) {
     goto err;
   }

   return 1;

 err:
   CBB_cleanup(&cbb);
   return 0;
 }

 int pkcs12_key_gen(const char *pass, size_t pass_len, const uint8_t *salt,
                    size_t salt_len, uint8_t id, uint32_t iterations,
                    size_t out_len, uint8_t *out, const EVP_MD *md) {
   // See https://tools.ietf.org/html/rfc7292#appendix-B. Quoted parts of the
   // specification have errata applied and other typos fixed.

   if (iterations < 1) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_ITERATION_COUNT);
     return 0;
   }

   int ret = 0;
   EVP_MD_CTX ctx;
   EVP_MD_CTX_init(&ctx);
   uint8_t *pass_raw = NULL, *I = NULL;
   size_t pass_raw_len = 0, I_len = 0;
   // If |pass| is NULL, we use the empty string rather than {0, 0} as the raw
   // password.
   if (pass != NULL &&
       !pkcs12_encode_password(pass, pass_len, &pass_raw, &pass_raw_len)) {
     goto err;
   }

   // In the spec, |block_size| is called "v", but measured in bits.
   size_t block_size = EVP_MD_block_size(md);

   // 1. Construct a string, D (the "diversifier"), by concatenating v/8 copies
   // of ID.
   uint8_t D[EVP_MAX_MD_BLOCK_SIZE];
   OPENSSL_memset(D, id, block_size);

   // 2. Concatenate copies of the salt together to create a string S of length
   // v(ceiling(s/v)) bits (the final copy of the salt may be truncated to
   // create S). Note that if the salt is the empty string, then so is S.
   //
   // 3. Concatenate copies of the password together to create a string P of
   // length v(ceiling(p/v)) bits (the final copy of the password may be
   // truncated to create P).  Note that if the password is the empty string,
   // then so is P.
   //
   // 4. Set I=S||P to be the concatenation of S and P.
   if (salt_len + block_size - 1 < salt_len ||
       pass_raw_len + block_size - 1 < pass_raw_len) {
     OPENSSL_PUT_ERROR(PKCS8, ERR_R_OVERFLOW);
     goto err;
   }
   size_t S_len = block_size * ((salt_len + block_size - 1) / block_size);
   size_t P_len = block_size * ((pass_raw_len + block_size - 1) / block_size);
   I_len = S_len + P_len;
   if (I_len < S_len) {
     OPENSSL_PUT_ERROR(PKCS8, ERR_R_OVERFLOW);
     goto err;
   }

   I = OPENSSL_malloc(I_len);
   if (I_len != 0 && I == NULL) {
     goto err;
   }

   for (size_t i = 0; i < S_len; i++) {
     I[i] = salt[i % salt_len];
   }
   for (size_t i = 0; i < P_len; i++) {
     I[i + S_len] = pass_raw[i % pass_raw_len];
   }

   while (out_len != 0) {
     // A. Set A_i=H^r(D||I). (i.e., the r-th hash of D||I,
     // H(H(H(... H(D||I))))
     uint8_t A[EVP_MAX_MD_SIZE];
     unsigned A_len;
     if (!EVP_DigestInit_ex(&ctx, md, NULL) ||
         !EVP_DigestUpdate(&ctx, D, block_size) ||
         !EVP_DigestUpdate(&ctx, I, I_len) ||
         !EVP_DigestFinal_ex(&ctx, A, &A_len)) {
       goto err;
     }
     for (uint32_t iter = 1; iter < iterations; iter++) {
       if (!EVP_DigestInit_ex(&ctx, md, NULL) ||
           !EVP_DigestUpdate(&ctx, A, A_len) ||
           !EVP_DigestFinal_ex(&ctx, A, &A_len)) {
         goto err;
       }
     }

     size_t todo = out_len < A_len ? out_len : A_len;
     OPENSSL_memcpy(out, A, todo);
     out += todo;
     out_len -= todo;
     if (out_len == 0) {
       break;
     }

     // B. Concatenate copies of A_i to create a string B of length v bits (the
     // final copy of A_i may be truncated to create B).
     uint8_t B[EVP_MAX_MD_BLOCK_SIZE];
     for (size_t i = 0; i < block_size; i++) {
       B[i] = A[i % A_len];
     }

     // C. Treating I as a concatenation I_0, I_1, ..., I_(k-1) of v-bit blocks,
     // where k=ceiling(s/v)+ceiling(p/v), modify I by setting I_j=(I_j+B+1) mod
     // 2^v for each j.
     assert(I_len % block_size == 0);
     for (size_t i = 0; i < I_len; i += block_size) {
       unsigned carry = 1;
       for (size_t j = block_size - 1; j < block_size; j--) {
         carry += I[i + j] + B[j];
         I[i + j] = (uint8_t)carry;
         carry >>= 8;
       }
     }
   }

   ret = 1;

 err:
   OPENSSL_free(I);
   OPENSSL_free(pass_raw);
   EVP_MD_CTX_cleanup(&ctx);
   return ret;
 }

 static int pkcs12_pbe_cipher_init(const struct pbe_suite *suite,
                                   EVP_CIPHER_CTX *ctx, uint32_t iterations,
                                   const char *pass, size_t pass_len,
                                   const uint8_t *salt, size_t salt_len,
                                   int is_encrypt) {
   const EVP_CIPHER *cipher = suite->cipher_func();
   const EVP_MD *md = suite->md_func();

   uint8_t key[EVP_MAX_KEY_LENGTH];
   uint8_t iv[EVP_MAX_IV_LENGTH];
   if (!pkcs12_key_gen(pass, pass_len, salt, salt_len, PKCS12_KEY_ID, iterations,
                       EVP_CIPHER_key_length(cipher), key, md) ||
       !pkcs12_key_gen(pass, pass_len, salt, salt_len, PKCS12_IV_ID, iterations,
                       EVP_CIPHER_iv_length(cipher), iv, md)) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_KEY_GEN_ERROR);
     return 0;
   }

   int ret = EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, is_encrypt);
   OPENSSL_cleanse(key, EVP_MAX_KEY_LENGTH);
   OPENSSL_cleanse(iv, EVP_MAX_IV_LENGTH);
   return ret;
 }

 static int pkcs12_pbe_decrypt_init(const struct pbe_suite *suite,
                                    EVP_CIPHER_CTX *ctx, const char *pass,
                                    size_t pass_len, CBS *param) {
   CBS pbe_param, salt;
   uint64_t iterations;
   if (!CBS_get_asn1(param, &pbe_param, CBS_ASN1_SEQUENCE) ||
       !CBS_get_asn1(&pbe_param, &salt, CBS_ASN1_OCTETSTRING) ||
       !CBS_get_asn1_uint64(&pbe_param, &iterations) ||
       CBS_len(&pbe_param) != 0 ||
       CBS_len(param) != 0) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);
     return 0;
   }

   if (!pkcs12_iterations_acceptable(iterations)) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_ITERATION_COUNT);
     return 0;
   }

   return pkcs12_pbe_cipher_init(suite, ctx, (uint32_t)iterations, pass,
                                 pass_len, CBS_data(&salt), CBS_len(&salt),
                                 0 /* decrypt */);
 }

 static const struct pbe_suite kBuiltinPBE[] = {
     {
         NID_pbe_WithSHA1And40BitRC2_CBC,
         // 1.2.840.113549.1.12.1.6
         {0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x01, 0x06},
         10,
         EVP_rc2_40_cbc,
         EVP_sha1,
         pkcs12_pbe_decrypt_init,
     },
     {
         NID_pbe_WithSHA1And128BitRC4,
         // 1.2.840.113549.1.12.1.1
         {0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x01, 0x01},
         10,
         EVP_rc4,
         EVP_sha1,
         pkcs12_pbe_decrypt_init,
     },
     {
         NID_pbe_WithSHA1And3_Key_TripleDES_CBC,
         // 1.2.840.113549.1.12.1.3
         {0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x01, 0x03},
         10,
         EVP_des_ede3_cbc,
         EVP_sha1,
         pkcs12_pbe_decrypt_init,
     },
     {
         NID_pbes2,
         // 1.2.840.113549.1.5.13
         {0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x05, 0x0d},
         9,
         NULL,
         NULL,
         PKCS5_pbe2_decrypt_init,
     },
 };

 static const struct pbe_suite *get_pkcs12_pbe_suite(int pbe_nid) {
   for (unsigned i = 0; i < OPENSSL_ARRAY_SIZE(kBuiltinPBE); i++) {
     if (kBuiltinPBE[i].pbe_nid == pbe_nid &&
         // If |cipher_func| or |md_func| are missing, this is a PBES2 scheme.
         kBuiltinPBE[i].cipher_func != NULL &&
         kBuiltinPBE[i].md_func != NULL) {
       return &kBuiltinPBE[i];
     }
   }

   return NULL;
 }

 int pkcs12_pbe_encrypt_init(CBB *out, EVP_CIPHER_CTX *ctx, int alg,
                             uint32_t iterations, const char *pass,
                             size_t pass_len, const uint8_t *salt,
                             size_t salt_len) {
   const struct pbe_suite *suite = get_pkcs12_pbe_suite(alg);
   if (suite == NULL) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNKNOWN_ALGORITHM);
     return 0;
   }

   // See RFC 2898, appendix A.3.
   CBB algorithm, oid, param, salt_cbb;
   if (!CBB_add_asn1(out, &algorithm, CBS_ASN1_SEQUENCE) ||
       !CBB_add_asn1(&algorithm, &oid, CBS_ASN1_OBJECT) ||
       !CBB_add_bytes(&oid, suite->oid, suite->oid_len) ||
       !CBB_add_asn1(&algorithm, &param, CBS_ASN1_SEQUENCE) ||
       !CBB_add_asn1(&param, &salt_cbb, CBS_ASN1_OCTETSTRING) ||
       !CBB_add_bytes(&salt_cbb, salt, salt_len) ||
       !CBB_add_asn1_uint64(&param, iterations) ||
       !CBB_flush(out)) {
     return 0;
   }

   return pkcs12_pbe_cipher_init(suite, ctx, iterations, pass, pass_len, salt,
                                 salt_len, 1 /* encrypt */);
 }

 int pkcs8_pbe_decrypt(uint8_t **out, size_t *out_len, CBS *algorithm,
                       const char *pass, size_t pass_len, const uint8_t *in,
                       size_t in_len) {
   int ret = 0;
   uint8_t *buf = NULL;;
   EVP_CIPHER_CTX ctx;
   EVP_CIPHER_CTX_init(&ctx);

   CBS obj;
   if (!CBS_get_asn1(algorithm, &obj, CBS_ASN1_OBJECT)) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);
     goto err;
   }

   const struct pbe_suite *suite = NULL;
   for (unsigned i = 0; i < OPENSSL_ARRAY_SIZE(kBuiltinPBE); i++) {
     if (CBS_mem_equal(&obj, kBuiltinPBE[i].oid, kBuiltinPBE[i].oid_len)) {
       suite = &kBuiltinPBE[i];
       break;
     }
   }
   if (suite == NULL) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNKNOWN_ALGORITHM);
     goto err;
   }

   if (!suite->decrypt_init(suite, &ctx, pass, pass_len, algorithm)) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_KEYGEN_FAILURE);
     goto err;
   }

   buf = OPENSSL_malloc(in_len);
   if (buf == NULL) {
     goto err;
   }

   if (in_len > INT_MAX) {
     OPENSSL_PUT_ERROR(PKCS8, ERR_R_OVERFLOW);
     goto err;
   }

   int n1, n2;
   if (!EVP_DecryptUpdate(&ctx, buf, &n1, in, (int)in_len) ||
       !EVP_DecryptFinal_ex(&ctx, buf + n1, &n2)) {
     goto err;
   }

   *out = buf;
   *out_len = n1 + n2;
   ret = 1;
   buf = NULL;

 err:
   OPENSSL_free(buf);
   EVP_CIPHER_CTX_cleanup(&ctx);
   return ret;
 }

 EVP_PKEY *PKCS8_parse_encrypted_private_key(CBS *cbs, const char *pass,
                                             size_t pass_len) {
   // See RFC 5208, section 6.
   CBS epki, algorithm, ciphertext;
   if (!CBS_get_asn1(cbs, &epki, CBS_ASN1_SEQUENCE) ||
       !CBS_get_asn1(&epki, &algorithm, CBS_ASN1_SEQUENCE) ||
       !CBS_get_asn1(&epki, &ciphertext, CBS_ASN1_OCTETSTRING) ||
       CBS_len(&epki) != 0) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);
     return 0;
   }

   uint8_t *out;
   size_t out_len;
   if (!pkcs8_pbe_decrypt(&out, &out_len, &algorithm, pass, pass_len,
                          CBS_data(&ciphertext), CBS_len(&ciphertext))) {
     return 0;
   }

   CBS pki;
   CBS_init(&pki, out, out_len);
   EVP_PKEY *ret = EVP_parse_private_key(&pki);
   OPENSSL_free(out);
   return ret;
 }

 int PKCS8_marshal_encrypted_private_key(CBB *out, int pbe_nid,
                                         const EVP_CIPHER *cipher,
                                         const char *pass, size_t pass_len,
                                         const uint8_t *salt, size_t salt_len,
                                         int iterations, const EVP_PKEY *pkey) {
   int ret = 0;
   uint8_t *plaintext = NULL, *salt_buf = NULL;
   size_t plaintext_len = 0;
   EVP_CIPHER_CTX ctx;
   EVP_CIPHER_CTX_init(&ctx);

   // Generate a random salt if necessary.
   if (salt == NULL) {
     if (salt_len == 0) {
       salt_len = PKCS5_SALT_LEN;
     }

     salt_buf = OPENSSL_malloc(salt_len);
     if (salt_buf == NULL ||
         !RAND_bytes(salt_buf, salt_len)) {
       goto err;
     }

     salt = salt_buf;
   }

   if (iterations <= 0) {
     iterations = PKCS12_DEFAULT_ITER;
   }

   // Serialize the input key.
   CBB plaintext_cbb;
   if (!CBB_init(&plaintext_cbb, 128) ||
       !EVP_marshal_private_key(&plaintext_cbb, pkey) ||
       !CBB_finish(&plaintext_cbb, &plaintext, &plaintext_len)) {
     CBB_cleanup(&plaintext_cbb);
     goto err;
   }

   CBB epki;
   if (!CBB_add_asn1(out, &epki, CBS_ASN1_SEQUENCE)) {
     goto err;
   }

   // TODO(davidben): OpenSSL has since extended |pbe_nid| to control either the
   // PBES1 scheme or the PBES2 PRF. E.g. passing |NID_hmacWithSHA256| will
   // select PBES2 with HMAC-SHA256 as the PRF. Implement this if anything uses
   // it. See 5693a30813a031d3921a016a870420e7eb93ec90 in OpenSSL.
   int alg_ok;
   if (pbe_nid == -1) {
     alg_ok = PKCS5_pbe2_encrypt_init(&epki, &ctx, cipher, (uint32_t)iterations,
                                      pass, pass_len, salt, salt_len);
   } else {
     alg_ok = pkcs12_pbe_encrypt_init(&epki, &ctx, pbe_nid, (uint32_t)iterations,
                                      pass, pass_len, salt, salt_len);
   }
   if (!alg_ok) {
     goto err;
   }

   size_t max_out = plaintext_len + EVP_CIPHER_CTX_block_size(&ctx);
   if (max_out < plaintext_len) {
     OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_TOO_LONG);
     goto err;
   }

   CBB ciphertext;
   uint8_t *ptr;
   int n1, n2;
   if (!CBB_add_asn1(&epki, &ciphertext, CBS_ASN1_OCTETSTRING) ||
       !CBB_reserve(&ciphertext, &ptr, max_out) ||
       !EVP_CipherUpdate(&ctx, ptr, &n1, plaintext, plaintext_len) ||
       !EVP_CipherFinal_ex(&ctx, ptr + n1, &n2) ||
       !CBB_did_write(&ciphertext, n1 + n2) ||
       !CBB_flush(out)) {
     goto err;
   }

   ret = 1;

 err:
   OPENSSL_free(plaintext);
   OPENSSL_free(salt_buf);
   EVP_CIPHER_CTX_cleanup(&ctx);
   return ret;
 }
	/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
	* project 1999.
	*/
	/* ====================================================================
	* Copyright (c) 1999 The OpenSSL Project. All rights reserved.
	*
	* 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 above 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 acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
	*
	* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
	* endorse or promote products derived from this software without
	* prior written permission. For written permission, please contact
	* licensing@OpenSSL.org.
	*
	* 5. Products derived from this software may not be called "OpenSSL"
	* nor may "OpenSSL" appear in their names without prior written
	* permission of the OpenSSL Project.
	*
	* 6. Redistributions of any form whatsoever must retain the following
	* acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
	*
	* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
	* EXPRESSED 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 OpenSSL PROJECT OR
	* ITS 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.
	* ====================================================================
	*
	* This product includes cryptographic software written by Eric Young
	* (eay@cryptsoft.com). This product includes software written by Tim
	* Hudson (tjh@cryptsoft.com). */

	#include <openssl/pkcs8.h>

	#include <assert.h>
	#include <limits.h>
	#include <string.h>

	#include <openssl/bytestring.h>
	#include <openssl/cipher.h>
	#include <openssl/digest.h>
	#include <openssl/err.h>
	#include <openssl/mem.h>
	#include <openssl/nid.h>
	#include <openssl/rand.h>

	#include "internal.h"
	#include "../bytestring/internal.h"
	#include "../internal.h"


	static int pkcs12_encode_password(const char in, size_t in_len, uint8_t *out,
	size_t *out_len) {
	CBB cbb;
	if (!CBB_init(&cbb, in_len * 2)) {
	return 0;
	}

	// Convert the password to BMPString, or UCS-2. See
	// https://tools.ietf.org/html/rfc7292#appendix-B.1.
	CBS cbs;
	CBS_init(&cbs, (const uint8_t *)in, in_len);
	while (CBS_len(&cbs) != 0) {
	uint32_t c;
	if (!cbs_get_utf8(&cbs, &c) \|\|
	!cbb_add_ucs2_be(&cbb, c)) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_INVALID_CHARACTERS);
	goto err;
	}
	}

	// Terminate the result with a UCS-2 NUL.
	if (!cbb_add_ucs2_be(&cbb, 0) \|\|
	!CBB_finish(&cbb, out, out_len)) {
	goto err;
	}

	return 1;

	err:
	CBB_cleanup(&cbb);
	return 0;
	}

	int pkcs12_key_gen(const char pass, size_t pass_len, const uint8_t salt,
	size_t salt_len, uint8_t id, uint32_t iterations,
	size_t out_len, uint8_t out, const EVP_MD md) {
	// See https://tools.ietf.org/html/rfc7292#appendix-B. Quoted parts of the
	// specification have errata applied and other typos fixed.

	if (iterations < 1) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_ITERATION_COUNT);
	return 0;
	}

	int ret = 0;
	EVP_MD_CTX ctx;
	EVP_MD_CTX_init(&ctx);
	uint8_t pass_raw = NULL, I = NULL;
	size_t pass_raw_len = 0, I_len = 0;
	// If \|pass\| is NULL, we use the empty string rather than {0, 0} as the raw
	// password.
	if (pass != NULL &&
	!pkcs12_encode_password(pass, pass_len, &pass_raw, &pass_raw_len)) {
	goto err;
	}

	// In the spec, \|block_size\| is called "v", but measured in bits.
	size_t block_size = EVP_MD_block_size(md);

	// 1. Construct a string, D (the "diversifier"), by concatenating v/8 copies
	// of ID.
	uint8_t D[EVP_MAX_MD_BLOCK_SIZE];
	OPENSSL_memset(D, id, block_size);

	// 2. Concatenate copies of the salt together to create a string S of length
	// v(ceiling(s/v)) bits (the final copy of the salt may be truncated to
	// create S). Note that if the salt is the empty string, then so is S.
	//
	// 3. Concatenate copies of the password together to create a string P of
	// length v(ceiling(p/v)) bits (the final copy of the password may be
	// truncated to create P). Note that if the password is the empty string,
	// then so is P.
	//
	// 4. Set I=S\|\|P to be the concatenation of S and P.
	if (salt_len + block_size - 1 < salt_len \|\|
	pass_raw_len + block_size - 1 < pass_raw_len) {
	OPENSSL_PUT_ERROR(PKCS8, ERR_R_OVERFLOW);
	goto err;
	}
	size_t S_len = block_size * ((salt_len + block_size - 1) / block_size);
	size_t P_len = block_size * ((pass_raw_len + block_size - 1) / block_size);
	I_len = S_len + P_len;
	if (I_len < S_len) {
	OPENSSL_PUT_ERROR(PKCS8, ERR_R_OVERFLOW);
	goto err;
	}

	I = OPENSSL_malloc(I_len);
	if (I_len != 0 && I == NULL) {
	goto err;
	}

	for (size_t i = 0; i < S_len; i++) {
	I[i] = salt[i % salt_len];
	}
	for (size_t i = 0; i < P_len; i++) {
	I[i + S_len] = pass_raw[i % pass_raw_len];
	}

	while (out_len != 0) {
	// A. Set A_i=H^r(D\|\|I). (i.e., the r-th hash of D\|\|I,
	// H(H(H(... H(D\|\|I))))
	uint8_t A[EVP_MAX_MD_SIZE];
	unsigned A_len;
	if (!EVP_DigestInit_ex(&ctx, md, NULL) \|\|
	!EVP_DigestUpdate(&ctx, D, block_size) \|\|
	!EVP_DigestUpdate(&ctx, I, I_len) \|\|
	!EVP_DigestFinal_ex(&ctx, A, &A_len)) {
	goto err;
	}
	for (uint32_t iter = 1; iter < iterations; iter++) {
	if (!EVP_DigestInit_ex(&ctx, md, NULL) \|\|
	!EVP_DigestUpdate(&ctx, A, A_len) \|\|
	!EVP_DigestFinal_ex(&ctx, A, &A_len)) {
	goto err;
	}
	}

	size_t todo = out_len < A_len ? out_len : A_len;
	OPENSSL_memcpy(out, A, todo);
	out += todo;
	out_len -= todo;
	if (out_len == 0) {
	break;
	}

	// B. Concatenate copies of A_i to create a string B of length v bits (the
	// final copy of A_i may be truncated to create B).
	uint8_t B[EVP_MAX_MD_BLOCK_SIZE];
	for (size_t i = 0; i < block_size; i++) {
	B[i] = A[i % A_len];
	}

	// C. Treating I as a concatenation I_0, I_1, ..., I_(k-1) of v-bit blocks,
	// where k=ceiling(s/v)+ceiling(p/v), modify I by setting I_j=(I_j+B+1) mod
	// 2^v for each j.
	assert(I_len % block_size == 0);
	for (size_t i = 0; i < I_len; i += block_size) {
	unsigned carry = 1;
	for (size_t j = block_size - 1; j < block_size; j--) {
	carry += I[i + j] + B[j];
	I[i + j] = (uint8_t)carry;
	carry >>= 8;
	}
	}
	}

	ret = 1;

	err:
	OPENSSL_free(I);
	OPENSSL_free(pass_raw);
	EVP_MD_CTX_cleanup(&ctx);
	return ret;
	}

	static int pkcs12_pbe_cipher_init(const struct pbe_suite *suite,
	EVP_CIPHER_CTX *ctx, uint32_t iterations,
	const char *pass, size_t pass_len,
	const uint8_t *salt, size_t salt_len,
	int is_encrypt) {
	const EVP_CIPHER *cipher = suite->cipher_func();
	const EVP_MD *md = suite->md_func();

	uint8_t key[EVP_MAX_KEY_LENGTH];
	uint8_t iv[EVP_MAX_IV_LENGTH];
	if (!pkcs12_key_gen(pass, pass_len, salt, salt_len, PKCS12_KEY_ID, iterations,
	EVP_CIPHER_key_length(cipher), key, md) \|\|
	!pkcs12_key_gen(pass, pass_len, salt, salt_len, PKCS12_IV_ID, iterations,
	EVP_CIPHER_iv_length(cipher), iv, md)) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_KEY_GEN_ERROR);
	return 0;
	}

	int ret = EVP_CipherInit_ex(ctx, cipher, NULL, key, iv, is_encrypt);
	OPENSSL_cleanse(key, EVP_MAX_KEY_LENGTH);
	OPENSSL_cleanse(iv, EVP_MAX_IV_LENGTH);
	return ret;
	}

	static int pkcs12_pbe_decrypt_init(const struct pbe_suite *suite,
	EVP_CIPHER_CTX ctx, const char pass,
	size_t pass_len, CBS *param) {
	CBS pbe_param, salt;
	uint64_t iterations;
	if (!CBS_get_asn1(param, &pbe_param, CBS_ASN1_SEQUENCE) \|\|
	!CBS_get_asn1(&pbe_param, &salt, CBS_ASN1_OCTETSTRING) \|\|
	!CBS_get_asn1_uint64(&pbe_param, &iterations) \|\|
	CBS_len(&pbe_param) != 0 \|\|
	CBS_len(param) != 0) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);
	return 0;
	}

	if (!pkcs12_iterations_acceptable(iterations)) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_BAD_ITERATION_COUNT);
	return 0;
	}

	return pkcs12_pbe_cipher_init(suite, ctx, (uint32_t)iterations, pass,
	pass_len, CBS_data(&salt), CBS_len(&salt),
	0 /* decrypt */);
	}

	static const struct pbe_suite kBuiltinPBE[] = {
	{
	NID_pbe_WithSHA1And40BitRC2_CBC,
	// 1.2.840.113549.1.12.1.6
	{0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x01, 0x06},
	10,
	EVP_rc2_40_cbc,
	EVP_sha1,
	pkcs12_pbe_decrypt_init,
	},
	{
	NID_pbe_WithSHA1And128BitRC4,
	// 1.2.840.113549.1.12.1.1
	{0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x01, 0x01},
	10,
	EVP_rc4,
	EVP_sha1,
	pkcs12_pbe_decrypt_init,
	},
	{
	NID_pbe_WithSHA1And3_Key_TripleDES_CBC,
	// 1.2.840.113549.1.12.1.3
	{0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x0c, 0x01, 0x03},
	10,
	EVP_des_ede3_cbc,
	EVP_sha1,
	pkcs12_pbe_decrypt_init,
	},
	{
	NID_pbes2,
	// 1.2.840.113549.1.5.13
	{0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x05, 0x0d},
	9,
	NULL,
	NULL,
	PKCS5_pbe2_decrypt_init,
	},
	};

	static const struct pbe_suite *get_pkcs12_pbe_suite(int pbe_nid) {
	for (unsigned i = 0; i < OPENSSL_ARRAY_SIZE(kBuiltinPBE); i++) {
	if (kBuiltinPBE[i].pbe_nid == pbe_nid &&
	// If \|cipher_func\| or \|md_func\| are missing, this is a PBES2 scheme.
	kBuiltinPBE[i].cipher_func != NULL &&
	kBuiltinPBE[i].md_func != NULL) {
	return &kBuiltinPBE[i];
	}
	}

	return NULL;
	}

	int pkcs12_pbe_encrypt_init(CBB out, EVP_CIPHER_CTX ctx, int alg,
	uint32_t iterations, const char *pass,
	size_t pass_len, const uint8_t *salt,
	size_t salt_len) {
	const struct pbe_suite *suite = get_pkcs12_pbe_suite(alg);
	if (suite == NULL) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNKNOWN_ALGORITHM);
	return 0;
	}

	// See RFC 2898, appendix A.3.
	CBB algorithm, oid, param, salt_cbb;
	if (!CBB_add_asn1(out, &algorithm, CBS_ASN1_SEQUENCE) \|\|
	!CBB_add_asn1(&algorithm, &oid, CBS_ASN1_OBJECT) \|\|
	!CBB_add_bytes(&oid, suite->oid, suite->oid_len) \|\|
	!CBB_add_asn1(&algorithm, &param, CBS_ASN1_SEQUENCE) \|\|
	!CBB_add_asn1(&param, &salt_cbb, CBS_ASN1_OCTETSTRING) \|\|
	!CBB_add_bytes(&salt_cbb, salt, salt_len) \|\|
	!CBB_add_asn1_uint64(&param, iterations) \|\|
	!CBB_flush(out)) {
	return 0;
	}

	return pkcs12_pbe_cipher_init(suite, ctx, iterations, pass, pass_len, salt,
	salt_len, 1 /* encrypt */);
	}

	int pkcs8_pbe_decrypt(uint8_t *out, size_t out_len, CBS *algorithm,
	const char pass, size_t pass_len, const uint8_t in,
	size_t in_len) {
	int ret = 0;
	uint8_t *buf = NULL;;
	EVP_CIPHER_CTX ctx;
	EVP_CIPHER_CTX_init(&ctx);

	CBS obj;
	if (!CBS_get_asn1(algorithm, &obj, CBS_ASN1_OBJECT)) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);
	goto err;
	}

	const struct pbe_suite *suite = NULL;
	for (unsigned i = 0; i < OPENSSL_ARRAY_SIZE(kBuiltinPBE); i++) {
	if (CBS_mem_equal(&obj, kBuiltinPBE[i].oid, kBuiltinPBE[i].oid_len)) {
	suite = &kBuiltinPBE[i];
	break;
	}
	}
	if (suite == NULL) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_UNKNOWN_ALGORITHM);
	goto err;
	}

	if (!suite->decrypt_init(suite, &ctx, pass, pass_len, algorithm)) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_KEYGEN_FAILURE);
	goto err;
	}

	buf = OPENSSL_malloc(in_len);
	if (buf == NULL) {
	goto err;
	}

	if (in_len > INT_MAX) {
	OPENSSL_PUT_ERROR(PKCS8, ERR_R_OVERFLOW);
	goto err;
	}

	int n1, n2;
	if (!EVP_DecryptUpdate(&ctx, buf, &n1, in, (int)in_len) \|\|
	!EVP_DecryptFinal_ex(&ctx, buf + n1, &n2)) {
	goto err;
	}

	*out = buf;
	*out_len = n1 + n2;
	ret = 1;
	buf = NULL;

	err:
	OPENSSL_free(buf);
	EVP_CIPHER_CTX_cleanup(&ctx);
	return ret;
	}

	EVP_PKEY PKCS8_parse_encrypted_private_key(CBS cbs, const char *pass,
	size_t pass_len) {
	// See RFC 5208, section 6.
	CBS epki, algorithm, ciphertext;
	if (!CBS_get_asn1(cbs, &epki, CBS_ASN1_SEQUENCE) \|\|
	!CBS_get_asn1(&epki, &algorithm, CBS_ASN1_SEQUENCE) \|\|
	!CBS_get_asn1(&epki, &ciphertext, CBS_ASN1_OCTETSTRING) \|\|
	CBS_len(&epki) != 0) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_DECODE_ERROR);
	return 0;
	}

	uint8_t *out;
	size_t out_len;
	if (!pkcs8_pbe_decrypt(&out, &out_len, &algorithm, pass, pass_len,
	CBS_data(&ciphertext), CBS_len(&ciphertext))) {
	return 0;
	}

	CBS pki;
	CBS_init(&pki, out, out_len);
	EVP_PKEY *ret = EVP_parse_private_key(&pki);
	OPENSSL_free(out);
	return ret;
	}

	int PKCS8_marshal_encrypted_private_key(CBB *out, int pbe_nid,
	const EVP_CIPHER *cipher,
	const char *pass, size_t pass_len,
	const uint8_t *salt, size_t salt_len,
	int iterations, const EVP_PKEY *pkey) {
	int ret = 0;
	uint8_t plaintext = NULL, salt_buf = NULL;
	size_t plaintext_len = 0;
	EVP_CIPHER_CTX ctx;
	EVP_CIPHER_CTX_init(&ctx);

	// Generate a random salt if necessary.
	if (salt == NULL) {
	if (salt_len == 0) {
	salt_len = PKCS5_SALT_LEN;
	}

	salt_buf = OPENSSL_malloc(salt_len);
	if (salt_buf == NULL \|\|
	!RAND_bytes(salt_buf, salt_len)) {
	goto err;
	}

	salt = salt_buf;
	}

	if (iterations <= 0) {
	iterations = PKCS12_DEFAULT_ITER;
	}

	// Serialize the input key.
	CBB plaintext_cbb;
	if (!CBB_init(&plaintext_cbb, 128) \|\|
	!EVP_marshal_private_key(&plaintext_cbb, pkey) \|\|
	!CBB_finish(&plaintext_cbb, &plaintext, &plaintext_len)) {
	CBB_cleanup(&plaintext_cbb);
	goto err;
	}

	CBB epki;
	if (!CBB_add_asn1(out, &epki, CBS_ASN1_SEQUENCE)) {
	goto err;
	}

	// TODO(davidben): OpenSSL has since extended \|pbe_nid\| to control either the
	// PBES1 scheme or the PBES2 PRF. E.g. passing \|NID_hmacWithSHA256\| will
	// select PBES2 with HMAC-SHA256 as the PRF. Implement this if anything uses
	// it. See 5693a30813a031d3921a016a870420e7eb93ec90 in OpenSSL.
	int alg_ok;
	if (pbe_nid == -1) {
	alg_ok = PKCS5_pbe2_encrypt_init(&epki, &ctx, cipher, (uint32_t)iterations,
	pass, pass_len, salt, salt_len);
	} else {
	alg_ok = pkcs12_pbe_encrypt_init(&epki, &ctx, pbe_nid, (uint32_t)iterations,
	pass, pass_len, salt, salt_len);
	}
	if (!alg_ok) {
	goto err;
	}

	size_t max_out = plaintext_len + EVP_CIPHER_CTX_block_size(&ctx);
	if (max_out < plaintext_len) {
	OPENSSL_PUT_ERROR(PKCS8, PKCS8_R_TOO_LONG);
	goto err;
	}

	CBB ciphertext;
	uint8_t *ptr;
	int n1, n2;
	if (!CBB_add_asn1(&epki, &ciphertext, CBS_ASN1_OCTETSTRING) \|\|
	!CBB_reserve(&ciphertext, &ptr, max_out) \|\|
	!EVP_CipherUpdate(&ctx, ptr, &n1, plaintext, plaintext_len) \|\|
	!EVP_CipherFinal_ex(&ctx, ptr + n1, &n2) \|\|
	!CBB_did_write(&ciphertext, n1 + n2) \|\|
	!CBB_flush(out)) {
	goto err;
	}

	ret = 1;

	err:
	OPENSSL_free(plaintext);
	OPENSSL_free(salt_buf);
	EVP_CIPHER_CTX_cleanup(&ctx);
	return ret;
	}