int
init_crypto(crypto_ctx_t *cctx, uchar_t *pwd, int pwd_len, int crypto_alg,
uchar_t *salt, int saltlen, uint64_t nonce, int enc_dec)
{
if (crypto_alg == CRYPTO_ALG_AES) {
aes_ctx_t *actx = malloc(sizeof (aes_ctx_t));
if (enc_dec) {
/*
* Encryption init.
*/
cctx->salt = malloc(32);
salt = cctx->salt;
cctx->saltlen = 32;
if (RAND_status() != 1 || RAND_bytes(salt, 32) != 1) {
if (geturandom_bytes(salt) != 0) {
uchar_t sb[64];
int b;
struct timespec tp;
b = 0;
/* No good random pool is populated/available. What to do ? */
if (clock_gettime(CLOCK_MONOTONIC, &tp) == -1) {
time((time_t *)&sb[b]);
b += 8;
} else {
uint64_t v;
v = tp.tv_sec * 1000UL + tp.tv_nsec;
*((uint64_t *)&sb[b]) = v;
b += 8;
}
*((uint32_t *)&sb[b]) = rand();
b += 4;
*((uint32_t *)&sb[b]) = getpid();
b += 4;
compute_checksum(&sb[b], CKSUM_SHA256, sb, b);
b = 8 + 4;
*((uint32_t *)&sb[b]) = rand();
compute_checksum(salt, CKSUM_SHA256, &sb[b], 32 + 4);
}
}
/*
* Zero nonce (arg #6) since it will be generated.
*/
if (aes_init(actx, salt, 32, pwd, pwd_len, 0, enc_dec) != 0) {
fprintf(stderr, "Failed to initialize AES context\n");
return (-1);
}
} else {
/*
* Decryption init.
* Pass given nonce and salt.
*/
if (saltlen > MAX_SALTLEN) {
fprintf(stderr, "Salt too long. Max allowed length is %d\n",
MAX_SALTLEN);
return (-1);
}
cctx->salt = malloc(saltlen);
memcpy(cctx->salt, salt, saltlen);
if (aes_init(actx, cctx->salt, saltlen, pwd, pwd_len, nonce,
enc_dec) != 0) {
fprintf(stderr, "Failed to initialize AES context\n");
return (-1);
}
}
cctx->crypto_ctx = actx;
cctx->crypto_alg = crypto_alg;
cctx->enc_dec = enc_dec;
} else {
fprintf(stderr, "Unrecognized algorithm code: %d\n", crypto_alg);
return (-1);
}
return (0);
}
int
salsa20_init(salsa20_ctx_t *ctx, uchar_t *salt, int saltlen, uchar_t *pwd, int pwd_len,
uchar_t *nonce, int enc)
{
struct timespec tp;
uint64_t tv;
uchar_t num[25];
uchar_t IV[32];
uchar_t *key = ctx->pkey;
#ifndef _USE_PBK
int logN;
uint32_t r, p;
uint64_t N;
if (XSALSA20_CRYPTO_NONCEBYTES % 8) {
log_msg(LOG_ERR, 0, "XSALSA20_CRYPTO_NONCEBYTES is not a multiple of 8!\n");
return (-1);
}
pickparams(&logN, &r, &p);
N = (uint64_t)(1) << logN;
if (crypto_scrypt(pwd, pwd_len, salt, saltlen, N, r, p, key, ctx->keylen)) {
log_msg(LOG_ERR, 0, "Scrypt failed\n");
return (-1);
}
#else
rv = PKCS5_PBKDF2_HMAC(pwd, pwd_len, salt, saltlen, PBE_ROUNDS, EVP_sha256(),
ctx->keylen, key);
if (rv != ctx->keylen) {
log_msg(LOG_ERR, 0, "Key size is %d bytes - should be %d bits\n", i, ctx->keylen);
return (-1);
}
#endif
/*
* Copy the key. XSalsa20 core cipher always uses a 256-bit key. If we are using a
* 128-bit key then the key value is repeated twice to form a 256-bit value.
* This approach is based on the Salsa20 code submitted to eSTREAM. See the function
* ECRYPT_keysetup() in the Salsa20 submission:
* http://www.ecrypt.eu.org/stream/svn/viewcvs.cgi/ecrypt/trunk/submissions/salsa20/full/ref/salsa20.c?rev=161&view=auto
*
* The input values corresponding to a 256-bit key contain repeated values if key
* length is 128-bit.
*/
memcpy(ctx->key, key, ctx->keylen);
if (ctx->keylen < XSALSA20_CRYPTO_KEYBYTES) {
uchar_t *k;
k = ctx->key + ctx->keylen;
memcpy(k, key, XSALSA20_CRYPTO_KEYBYTES - ctx->keylen);
}
if (enc) {
int i;
uint64_t *n, *n1;
// Derive 192-bit nonce
if (RAND_status() != 1 || RAND_bytes(IV, XSALSA20_CRYPTO_NONCEBYTES) != 1) {
if (geturandom_bytes(IV, XSALSA20_CRYPTO_NONCEBYTES) != 0) {
if (clock_gettime(CLOCK_MONOTONIC, &tp) == -1) {
time((time_t *)&tv);
} else {
tv = tp.tv_sec * 1000UL + tp.tv_nsec;
}
sprintf((char *)num, "%" PRIu64, tv);
PKCS5_PBKDF2_HMAC((const char *)num, strlen((char *)num), salt,
saltlen, PBE_ROUNDS, EVP_sha256(), 32, IV);
}
}
n = (uint64_t *)IV;
n1 = (uint64_t *)(ctx->nonce);
for (i = 0; i < XSALSA20_CRYPTO_NONCEBYTES/8; i++) {
*n1 = LE64(*n);
n++;
n1++;
}
// Nullify stack components
memset(num, 0, 25);
memset(IV, 0, 32);
memset(&tp, 0, sizeof (tp));
tv = 0;
} else {
memcpy(ctx->nonce, nonce, XSALSA20_CRYPTO_NONCEBYTES);
memset(nonce, 0, XSALSA20_CRYPTO_NONCEBYTES);
}
return (0);
}
