/* read encrypted data on socket */
int
readenc (Shishi * h, int sock, char *buf, int *len, char *iv, int *ivlen,
Shishi_key * enckey)
{
char *out;
char *outbis;
char *iv2;
int rc;
int val;
int outlen;
int dlen = 0, blocksize, enctype, hashsize;
/* read size of message */
read (sock, &dlen, sizeof (int));
dlen = ntohl (dlen);
/* if 0 put read size to 0 */
if (!dlen)
{
*len = dlen;
return SHISHI_OK;
}
/* convert size to encryption size */
enctype = shishi_key_type (enckey);
blocksize = shishi_cipher_blocksize (enctype);
hashsize =
shishi_checksum_cksumlen (shishi_cipher_defaultcksumtype (enctype));
dlen += blocksize - 1 + 4;
if (shishi_key_type (enckey) != SHISHI_DES3_CBC_HMAC_SHA1_KD)
dlen += hashsize;
else
dlen += blocksize;
dlen /= blocksize;
dlen *= blocksize;
if (shishi_key_type (enckey) == SHISHI_DES3_CBC_HMAC_SHA1_KD)
dlen += hashsize;
/* read encrypted data */
outbis = malloc (dlen);
if (outbis == NULL)
{
printf ("Malloc error!\n");
return 1;
}
rc = read (sock, outbis, dlen);
if (rc != dlen)
{
printf ("Error during read socket\n");
return 1;
}
/* decrypt it */
rc =
shishi_decrypt_ivupdate (h, enckey, 1026, iv, *ivlen, &iv2, ivlen, outbis,
dlen, &out, &outlen);
if (rc != SHISHI_OK)
{
printf ("decryption error\n");
return 1;
}
/* len = first 4 bytes of decrypted data */
*len = ntohl (*((int *) out));
/* update iv */
memcpy (iv, iv2, *ivlen);
/* Temp patch to remove 5 unidentified bytes data from server */
memset (buf, 0, BUFLEN);
if ((unsigned char) out[4] == 255)
val = 5 + sizeof (int);
else
val = sizeof (int);
/* copy decrypted data to output */
memcpy (buf, out + val, strlen (out + val));
free (out);
free (outbis);
return SHISHI_OK;
}
/* read encrypted data on socket */
int
readenc (Shishi * h, int sock, char *buf, int *len, shishi_ivector * iv,
Shishi_key * enckey, int proto)
{
char *out;
char *outbis;
int rc;
int val;
int outlen;
int dlen = 0, blocksize, enctype, hashsize;
/* read size of message */
read (sock, &dlen, sizeof (int));
dlen = ntohl (dlen);
/* if 0 put read size to 0 */
if (!dlen)
{
*len = dlen;
return SHISHI_OK;
}
if (proto == 1)
*len = dlen;
/* convert size to encryption size */
enctype = shishi_key_type (enckey);
blocksize = shishi_cipher_blocksize (enctype);
hashsize =
shishi_checksum_cksumlen (shishi_cipher_defaultcksumtype (enctype));
switch (enctype)
{
case SHISHI_AES128_CTS_HMAC_SHA1_96:
case SHISHI_AES256_CTS_HMAC_SHA1_96:
dlen += 4 + hashsize + blocksize;
break;
case SHISHI_ARCFOUR_HMAC:
case SHISHI_ARCFOUR_HMAC_EXP:
dlen += 4 + 8 + blocksize - 1;
dlen /= blocksize;
dlen *= blocksize;
dlen += hashsize;
break;
case SHISHI_DES3_CBC_HMAC_SHA1_KD:
dlen += 4 + 2 * blocksize - 1;
dlen /= blocksize;
dlen *= blocksize;
dlen += hashsize;
break;
case SHISHI_DES_CBC_CRC:
dlen += 2 * blocksize - 1;
if (proto == 2)
dlen += 4;
dlen += hashsize;
dlen /= blocksize;
dlen *= blocksize;
break;
default:
dlen += blocksize - 1;
if (proto == 2)
dlen += 4;
dlen += hashsize;
dlen /= blocksize;
dlen *= blocksize;
break;
}
/* read encrypted data */
outbis = malloc (dlen);
if (outbis == NULL)
{
perror ("readenc()");
return 1;
}
rc = read (sock, outbis, dlen);
if (rc != dlen)
{
fprintf (stderr, "Error during read socket\n");
free (outbis);
return 1;
}
if (proto == 1)
{
rc =
shishi_decrypt (h, enckey, iv->keyusage, outbis, dlen, &out, &outlen);
if (rc != SHISHI_OK)
{
fprintf (stderr, "decryption error\n");
free (outbis);
return 1;
}
val = 0;
}
else
{
rc = shishi_crypto_decrypt (iv->ctx, outbis, dlen, &out, &outlen);
if (rc != SHISHI_OK)
{
fprintf (stderr, "decryption error\n");
free (outbis);
return 1;
}
/* in KCMDV0.2 first 4 bytes of decrypted data = len of data */
*len = ntohl (*((int *) out));
val = sizeof (int);
}
memset (buf, 0, BUFLEN);
/* copy decrypted data to output */
memcpy (buf, out + val, outlen - val);
free (out);
free (outbis);
return SHISHI_OK;
}
