src/crypto/crypto_gnutls.c

/*
 * WPA Supplicant / wrapper functions for libgcrypt
 * Copyright (c) 2004-2017, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"
#include <gcrypt.h>

#include "common.h"
#include "md5.h"
#include "sha1.h"
#include "sha256.h"
#include "sha384.h"
#include "sha512.h"
#include "crypto.h"

static int gnutls_digest_vector(int algo, size_t num_elem,
                                        const u8 *addr[], const size_t *len, u8 *mac)
{
          gcry_md_hd_t hd;
          unsigned char *p;
          size_t i;

          if (TEST_FAIL())
                    return -1;

          if (gcry_md_open(&hd, algo, 0) != GPG_ERR_NO_ERROR)
                    return -1;
          for (i = 0; i < num_elem; i++)
                    gcry_md_write(hd, addr[i], len[i]);
          p = gcry_md_read(hd, algo);
          if (p)
                    memcpy(mac, p, gcry_md_get_algo_dlen(algo));
          gcry_md_close(hd);
          return 0;
}


int md4_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_digest_vector(GCRY_MD_MD4, num_elem, addr, len, mac);
}


int des_encrypt(const u8 *clear, const u8 *key, u8 *cypher)
{
          gcry_cipher_hd_t hd;
          u8 pkey[8], next, tmp;
          int i;

          /* Add parity bits to the key */
          next = 0;
          for (i = 0; i < 7; i++) {
                    tmp = key[i];
                    pkey[i] = (tmp >> i) | next | 1;
                    next = tmp << (7 - i);
          }
          pkey[i] = next | 1;

          gcry_cipher_open(&hd, GCRY_CIPHER_DES, GCRY_CIPHER_MODE_ECB, 0);
          gcry_err_code(gcry_cipher_setkey(hd, pkey, 8));
          gcry_cipher_encrypt(hd, cypher, 8, clear, 8);
          gcry_cipher_close(hd);
          return 0;
}


int md5_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_digest_vector(GCRY_MD_MD5, num_elem, addr, len, mac);
}


int sha1_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_digest_vector(GCRY_MD_SHA1, num_elem, addr, len, mac);
}


int sha256_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_digest_vector(GCRY_MD_SHA256, num_elem, addr, len, mac);
}


int sha384_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_digest_vector(GCRY_MD_SHA384, num_elem, addr, len, mac);
}


int sha512_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_digest_vector(GCRY_MD_SHA512, num_elem, addr, len, mac);
}


static int gnutls_hmac_vector(int algo, const u8 *key, size_t key_len,
                                    size_t num_elem, const u8 *addr[],
                                    const size_t *len, u8 *mac)
{
          gcry_md_hd_t hd;
          unsigned char *p;
          size_t i;

          if (TEST_FAIL())
                    return -1;

          if (gcry_md_open(&hd, algo, GCRY_MD_FLAG_HMAC) != GPG_ERR_NO_ERROR)
                    return -1;
          if (gcry_md_setkey(hd, key, key_len) != GPG_ERR_NO_ERROR) {
                    gcry_md_close(hd);
                    return -1;
          }
          for (i = 0; i < num_elem; i++)
                    gcry_md_write(hd, addr[i], len[i]);
          p = gcry_md_read(hd, algo);
          if (p)
                    memcpy(mac, p, gcry_md_get_algo_dlen(algo));
          gcry_md_close(hd);
          return 0;
}


int hmac_md5_vector(const u8 *key, size_t key_len, size_t num_elem,
                        const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_hmac_vector(GCRY_MD_MD5, key, key_len, num_elem, addr,
                                          len, mac);
}


int hmac_md5(const u8 *key, size_t key_len, const u8 *data, size_t data_len,
               u8 *mac)
{
          return hmac_md5_vector(key, key_len, 1, &data, &data_len, mac);
}


int hmac_sha1_vector(const u8 *key, size_t key_len, size_t num_elem,
                         const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_hmac_vector(GCRY_MD_SHA1, key, key_len, num_elem, addr,
                                          len, mac);
}


int hmac_sha1(const u8 *key, size_t key_len, const u8 *data, size_t data_len,
                 u8 *mac)
{
          return hmac_sha1_vector(key, key_len, 1, &data, &data_len, mac);
}


#ifdef CONFIG_SHA256

int hmac_sha256_vector(const u8 *key, size_t key_len, size_t num_elem,
                           const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_hmac_vector(GCRY_MD_SHA256, key, key_len, num_elem, addr,
                                          len, mac);
}


int hmac_sha256(const u8 *key, size_t key_len, const u8 *data,
                    size_t data_len, u8 *mac)
{
          return hmac_sha256_vector(key, key_len, 1, &data, &data_len, mac);
}

#endif /* CONFIG_SHA256 */


#ifdef CONFIG_SHA384

int hmac_sha384_vector(const u8 *key, size_t key_len, size_t num_elem,
                           const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_hmac_vector(GCRY_MD_SHA384, key, key_len, num_elem, addr,
                                          len, mac);
}


int hmac_sha384(const u8 *key, size_t key_len, const u8 *data,
                    size_t data_len, u8 *mac)
{
          return hmac_sha384_vector(key, key_len, 1, &data, &data_len, mac);
}

#endif /* CONFIG_SHA384 */


#ifdef CONFIG_SHA512

int hmac_sha512_vector(const u8 *key, size_t key_len, size_t num_elem,
                           const u8 *addr[], const size_t *len, u8 *mac)
{
          return gnutls_hmac_vector(GCRY_MD_SHA512, key, key_len, num_elem, addr,
                                          len, mac);
}


int hmac_sha512(const u8 *key, size_t key_len, const u8 *data,
                    size_t data_len, u8 *mac)
{
          return hmac_sha512_vector(key, key_len, 1, &data, &data_len, mac);
}

#endif /* CONFIG_SHA512 */


void * aes_encrypt_init(const u8 *key, size_t len)
{
          gcry_cipher_hd_t hd;

          if (TEST_FAIL())
                    return NULL;

          if (gcry_cipher_open(&hd, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_ECB, 0) !=
              GPG_ERR_NO_ERROR) {
                    printf("cipher open failed\n");
                    return NULL;
          }
          if (gcry_cipher_setkey(hd, key, len) != GPG_ERR_NO_ERROR) {
                    printf("setkey failed\n");
                    gcry_cipher_close(hd);
                    return NULL;
          }

          return hd;
}


int aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
{
          gcry_cipher_hd_t hd = ctx;
          gcry_cipher_encrypt(hd, crypt, 16, plain, 16);
          return 0;
}


void aes_encrypt_deinit(void *ctx)
{
          gcry_cipher_hd_t hd = ctx;
          gcry_cipher_close(hd);
}


void * aes_decrypt_init(const u8 *key, size_t len)
{
          gcry_cipher_hd_t hd;

          if (TEST_FAIL())
                    return NULL;

          if (gcry_cipher_open(&hd, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_ECB, 0) !=
              GPG_ERR_NO_ERROR)
                    return NULL;
          if (gcry_cipher_setkey(hd, key, len) != GPG_ERR_NO_ERROR) {
                    gcry_cipher_close(hd);
                    return NULL;
          }

          return hd;
}


int aes_decrypt(void *ctx, const u8 *crypt, u8 *plain)
{
          gcry_cipher_hd_t hd = ctx;
          gcry_cipher_decrypt(hd, plain, 16, crypt, 16);
          return 0;
}


void aes_decrypt_deinit(void *ctx)
{
          gcry_cipher_hd_t hd = ctx;
          gcry_cipher_close(hd);
}


int crypto_dh_init(u8 generator, const u8 *prime, size_t prime_len, u8 *privkey,
                       u8 *pubkey)
{
          size_t pubkey_len, pad;

          if (os_get_random(privkey, prime_len) < 0)
                    return -1;
          if (os_memcmp(privkey, prime, prime_len) > 0) {
                    /* Make sure private value is smaller than prime */
                    privkey[0] = 0;
          }

          pubkey_len = prime_len;
          if (crypto_mod_exp(&generator, 1, privkey, prime_len, prime, prime_len,
                                 pubkey, &pubkey_len) < 0)
                    return -1;
          if (pubkey_len < prime_len) {
                    pad = prime_len - pubkey_len;
                    os_memmove(pubkey + pad, pubkey, pubkey_len);
                    os_memset(pubkey, 0, pad);
          }

          return 0;
}


int crypto_dh_derive_secret(u8 generator, const u8 *prime, size_t prime_len,
                                  const u8 *order, size_t order_len,
                                  const u8 *privkey, size_t privkey_len,
                                  const u8 *pubkey, size_t pubkey_len,
                                  u8 *secret, size_t *len)
{
          gcry_mpi_t pub = NULL;
          int res = -1;

          if (pubkey_len > prime_len ||
              (pubkey_len == prime_len &&
               os_memcmp(pubkey, prime, prime_len) >= 0))
                    return -1;

          if (gcry_mpi_scan(&pub, GCRYMPI_FMT_USG, pubkey, pubkey_len, NULL) !=
              GPG_ERR_NO_ERROR ||
              gcry_mpi_cmp_ui(pub, 1) <= 0)
                    goto fail;

          if (order) {
                    gcry_mpi_t p = NULL, q = NULL, tmp;
                    int failed;

                    /* verify: pubkey^q == 1 mod p */
                    tmp = gcry_mpi_new(prime_len * 8);
                    failed = !tmp ||
                              gcry_mpi_scan(&p, GCRYMPI_FMT_USG, prime, prime_len,
                                              NULL) != GPG_ERR_NO_ERROR ||
                              gcry_mpi_scan(&q, GCRYMPI_FMT_USG, order, order_len,
                                              NULL) != GPG_ERR_NO_ERROR;
                    if (!failed) {
                              gcry_mpi_powm(tmp, pub, q, p);
                              failed = gcry_mpi_cmp_ui(tmp, 1) != 0;
                    }
                    gcry_mpi_release(p);
                    gcry_mpi_release(q);
                    gcry_mpi_release(tmp);
                    if (failed)
                              goto fail;
          }

          res = crypto_mod_exp(pubkey, pubkey_len, privkey, privkey_len,
                                   prime, prime_len, secret, len);
fail:
          gcry_mpi_release(pub);
          return res;
}


int crypto_mod_exp(const u8 *base, size_t base_len,
                       const u8 *power, size_t power_len,
                       const u8 *modulus, size_t modulus_len,
                       u8 *result, size_t *result_len)
{
          gcry_mpi_t bn_base = NULL, bn_exp = NULL, bn_modulus = NULL,
                    bn_result = NULL;
          int ret = -1;

          if (gcry_mpi_scan(&bn_base, GCRYMPI_FMT_USG, base, base_len, NULL) !=
              GPG_ERR_NO_ERROR ||
              gcry_mpi_scan(&bn_exp, GCRYMPI_FMT_USG, power, power_len, NULL) !=
              GPG_ERR_NO_ERROR ||
              gcry_mpi_scan(&bn_modulus, GCRYMPI_FMT_USG, modulus, modulus_len,
                                NULL) != GPG_ERR_NO_ERROR)
                    goto error;
          bn_result = gcry_mpi_new(modulus_len * 8);

          gcry_mpi_powm(bn_result, bn_base, bn_exp, bn_modulus);

          if (gcry_mpi_print(GCRYMPI_FMT_USG, result, *result_len, result_len,
                                 bn_result) != GPG_ERR_NO_ERROR)
                    goto error;

          ret = 0;

error:
          gcry_mpi_release(bn_base);
          gcry_mpi_release(bn_exp);
          gcry_mpi_release(bn_modulus);
          gcry_mpi_release(bn_result);
          return ret;
}


struct crypto_cipher {
          gcry_cipher_hd_t enc;
          gcry_cipher_hd_t dec;
};


struct crypto_cipher * crypto_cipher_init(enum crypto_cipher_alg alg,
                                                    const u8 *iv, const u8 *key,
                                                    size_t key_len)
{
          struct crypto_cipher *ctx;
          gcry_error_t res;
          enum gcry_cipher_algos a;
          int ivlen;

          ctx = os_zalloc(sizeof(*ctx));
          if (ctx == NULL)
                    return NULL;

          switch (alg) {
          case CRYPTO_CIPHER_ALG_RC4:
                    a = GCRY_CIPHER_ARCFOUR;
                    res = gcry_cipher_open(&ctx->enc, a, GCRY_CIPHER_MODE_STREAM,
                                               0);
                    gcry_cipher_open(&ctx->dec, a, GCRY_CIPHER_MODE_STREAM, 0);
                    break;
          case CRYPTO_CIPHER_ALG_AES:
                    if (key_len == 24)
                              a = GCRY_CIPHER_AES192;
                    else if (key_len == 32)
                              a = GCRY_CIPHER_AES256;
                    else
                              a = GCRY_CIPHER_AES;
                    res = gcry_cipher_open(&ctx->enc, a, GCRY_CIPHER_MODE_CBC, 0);
                    gcry_cipher_open(&ctx->dec, a, GCRY_CIPHER_MODE_CBC, 0);
                    break;
          case CRYPTO_CIPHER_ALG_3DES:
                    a = GCRY_CIPHER_3DES;
                    res = gcry_cipher_open(&ctx->enc, a, GCRY_CIPHER_MODE_CBC, 0);
                    gcry_cipher_open(&ctx->dec, a, GCRY_CIPHER_MODE_CBC, 0);
                    break;
          case CRYPTO_CIPHER_ALG_DES:
                    a = GCRY_CIPHER_DES;
                    res = gcry_cipher_open(&ctx->enc, a, GCRY_CIPHER_MODE_CBC, 0);
                    gcry_cipher_open(&ctx->dec, a, GCRY_CIPHER_MODE_CBC, 0);
                    break;
          case CRYPTO_CIPHER_ALG_RC2:
                    if (key_len == 5)
                              a = GCRY_CIPHER_RFC2268_40;
                    else
                              a = GCRY_CIPHER_RFC2268_128;
                    res = gcry_cipher_open(&ctx->enc, a, GCRY_CIPHER_MODE_CBC, 0);
                    gcry_cipher_open(&ctx->dec, a, GCRY_CIPHER_MODE_CBC, 0);
                    break;
          default:
                    os_free(ctx);
                    return NULL;
          }

          if (res != GPG_ERR_NO_ERROR) {
                    os_free(ctx);
                    return NULL;
          }

          if (gcry_cipher_setkey(ctx->enc, key, key_len) != GPG_ERR_NO_ERROR ||
              gcry_cipher_setkey(ctx->dec, key, key_len) != GPG_ERR_NO_ERROR) {
                    gcry_cipher_close(ctx->enc);
                    gcry_cipher_close(ctx->dec);
                    os_free(ctx);
                    return NULL;
          }

          ivlen = gcry_cipher_get_algo_blklen(a);
          if (gcry_cipher_setiv(ctx->enc, iv, ivlen) != GPG_ERR_NO_ERROR ||
              gcry_cipher_setiv(ctx->dec, iv, ivlen) != GPG_ERR_NO_ERROR) {
                    gcry_cipher_close(ctx->enc);
                    gcry_cipher_close(ctx->dec);
                    os_free(ctx);
                    return NULL;
          }

          return ctx;
}


int crypto_cipher_encrypt(struct crypto_cipher *ctx, const u8 *plain,
                                u8 *crypt, size_t len)
{
          if (gcry_cipher_encrypt(ctx->enc, crypt, len, plain, len) !=
              GPG_ERR_NO_ERROR)
                    return -1;
          return 0;
}


int crypto_cipher_decrypt(struct crypto_cipher *ctx, const u8 *crypt,
                                u8 *plain, size_t len)
{
          if (gcry_cipher_decrypt(ctx->dec, plain, len, crypt, len) !=
              GPG_ERR_NO_ERROR)
                    return -1;
          return 0;
}


void crypto_cipher_deinit(struct crypto_cipher *ctx)
{
          gcry_cipher_close(ctx->enc);
          gcry_cipher_close(ctx->dec);
          os_free(ctx);
}