int
tls_connection_load_cipher(struct SSLConnection *conn)
{
if (conn->cipher_suite.cs1 != 0x00)
return 1;
if (conn->cipher_suite.cs2 == TLS_RSA_WITH_AES_256_CBC_SHA.cs2) {
conn->ciph = gcry_cipher_map_name("AES256");
} else if (conn->cipher_suite.cs2 == TLS_RSA_WITH_AES_128_CBC_SHA.cs2) {
conn->ciph = gcry_cipher_map_name("AES");
} else {
return 1;
}
return 0;
}
int init_My_crypto(My_crypto* obj, const char alg[], int mode) {
obj->_cipher = gcry_cipher_map_name(alg);
//ret->_md = gcry_md_map_name("MD5");
if (gcry_cipher_open(&(obj->_cipherhd), obj->_cipher, mode, 0) != GPG_ERR_NO_ERROR)
return -1;
return 0;
}
static crypto_t _cipher_new(crypto_t c, gchar *key,
const gchar *algoname,
const gint cipher_mode,
const guint cipher_flags)
{
gcry_error_t e;
c->algo = gcry_cipher_map_name(algoname);
if (c->algo ==0)
{
return (_fail(c, g_strdup_printf("algorithm `%s' was not available",
algoname)));
}
c->cipher.flags = cipher_flags;
c->cipher.mode = cipher_mode;
c->cipher.should_pad = (cipher_mode != GCRY_CIPHER_MODE_STREAM
&& cipher_mode != GCRY_CIPHER_MODE_CFB
&& cipher_mode != GCRY_CIPHER_MODE_OFB)
? TRUE
: FALSE;
c->cipher.blklen = gcry_cipher_get_algo_blklen(c->algo);
if (c->cipher.blklen ==0)
return (_fail(c, g_strdup("gcry_cipher_get_algo_blklen failed")));
e = gcry_cipher_open(&c->cipher.h, c->algo, cipher_mode, cipher_flags);
if (e != 0)
{
return (_fail(c, g_strdup_printf("gcry_cipher_open failed: %s",
gpg_strerror(e))));
}
return (_setkey(c, key));
}
static void
check_ciphers (void)
{
static int algos[] = {
GCRY_CIPHER_3DES,
GCRY_CIPHER_CAST5,
GCRY_CIPHER_BLOWFISH,
GCRY_CIPHER_AES,
GCRY_CIPHER_AES192,
GCRY_CIPHER_AES256,
GCRY_CIPHER_TWOFISH,
GCRY_CIPHER_TWOFISH128,
GCRY_CIPHER_DES,
GCRY_CIPHER_SERPENT128,
GCRY_CIPHER_SERPENT192,
GCRY_CIPHER_SERPENT256,
0
};
static int algos2[] = {
GCRY_CIPHER_ARCFOUR,
0
};
int i;
for (i = 0; algos[i]; i++)
{
if (verbose)
fprintf (stderr, "checking `%s' [%i]\n",
gcry_cipher_algo_name (algos[i]),
gcry_cipher_map_name (gcry_cipher_algo_name (algos[i])));
check_one_cipher (algos[i], GCRY_CIPHER_MODE_ECB, 0);
check_one_cipher (algos[i], GCRY_CIPHER_MODE_CFB, 0);
check_one_cipher (algos[i], GCRY_CIPHER_MODE_CBC, 0);
check_one_cipher (algos[i], GCRY_CIPHER_MODE_CBC, GCRY_CIPHER_CBC_CTS);
check_one_cipher (algos[i], GCRY_CIPHER_MODE_CTR, 0);
}
for (i = 0; algos2[i]; i++)
{
if (verbose)
fprintf (stderr, "checking `%s'\n",
gcry_cipher_algo_name (algos2[i]));
check_one_cipher (algos2[i], GCRY_CIPHER_MODE_STREAM, 0);
}
/* we have now run all cipher's selftests */
/* TODO: add some extra encryption to test the higher level functions */
}
/** \brief init the gcry_md_hd
*
* - this init is assumed to be done everytime it is done for ciph_type
*/
bool skey_ciph_t::init_gcry_hd() throw()
{
const skey_ciph_algo_t &algo = ciph_type.get_algo();
// get the algo from the algo_str
int gcry_cipher_algo = gcry_cipher_map_name( algo.to_string().c_str() );
// if the algo_str isnt supported, throw an exception
if( !gcry_cipher_algo ){
KLOG_ERR("Can't map " << algo.to_string() << " in gcrypt cipher_map_name");
return true;
}
// open the gcrypt cipher
if( gcry_cipher_open(&gcry_cipher_hd, gcry_cipher_algo, get_gcry_cipher_mode(), GCRY_CIPHER_SECURE) ){
KLOG_ERR("Can't open " << ciph_type << " in gcrypt cipher_open");
return true;
}
// return false if no error occured
return false;
}
void
cipher_bench (char **argv, int argc)
{
int i, algo;
bench_print_section ("cipher", "Cipher");
if (argv && argc)
{
for (i = 0; i < argc; i++)
{
algo = gcry_cipher_map_name (argv[i]);
if (algo)
_cipher_bench (algo);
}
}
else
{
for (i = 1; i < 400; i++)
if (!gcry_cipher_test_algo (i))
_cipher_bench (i);
}
}
/* Initialize the data encryption key (session key). */
static int
init_dek (DEK dek)
{
int rc=0, mode, i;
dek->algo = gcry_cipher_map_name (dek->algoid);
mode = gcry_cipher_mode_from_oid (dek->algoid);
if (!dek->algo || !mode)
{
log_error ("unsupported algorithm `%s'\n", dek->algoid);
return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
}
/* Extra check for algorithms we consider to be too weak for
encryption, although we support them for decryption. Note that
there is another check below discriminating on the key length. */
switch (dek->algo)
{
case GCRY_CIPHER_DES:
case GCRY_CIPHER_RFC2268_40:
log_error ("cipher algorithm `%s' not allowed: too weak\n",
gcry_cipher_algo_name (dek->algo));
return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
default:
break;
}
dek->keylen = gcry_cipher_get_algo_keylen (dek->algo);
if (!dek->keylen || dek->keylen > sizeof (dek->key))
return gpg_error (GPG_ERR_BUG);
dek->ivlen = gcry_cipher_get_algo_blklen (dek->algo);
if (!dek->ivlen || dek->ivlen > sizeof (dek->iv))
return gpg_error (GPG_ERR_BUG);
/* Make sure we don't use weak keys. */
if (dek->keylen < 100/8)
{
log_error ("key length of `%s' too small\n", dek->algoid);
return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
}
rc = gcry_cipher_open (&dek->chd, dek->algo, mode, GCRY_CIPHER_SECURE);
if (rc)
{
log_error ("failed to create cipher context: %s\n", gpg_strerror (rc));
return rc;
}
for (i=0; i < 8; i++)
{
gcry_randomize (dek->key, dek->keylen, GCRY_STRONG_RANDOM );
rc = gcry_cipher_setkey (dek->chd, dek->key, dek->keylen);
if (gpg_err_code (rc) != GPG_ERR_WEAK_KEY)
break;
log_info(_("weak key created - retrying\n") );
}
if (rc)
{
log_error ("failed to set the key: %s\n", gpg_strerror (rc));
gcry_cipher_close (dek->chd);
dek->chd = NULL;
return rc;
}
gcry_create_nonce (dek->iv, dek->ivlen);
rc = gcry_cipher_setiv (dek->chd, dek->iv, dek->ivlen);
if (rc)
{
log_error ("failed to set the IV: %s\n", gpg_strerror (rc));
gcry_cipher_close (dek->chd);
dek->chd = NULL;
return rc;
}
return 0;
}
/** \brief return the gcrypt algo id
*/
int skey_ciph_t::get_gcry_cipher_algo() const throw()
{
const skey_ciph_algo_t &algo = ciph_type.get_algo();
int gcry_cipher_algo= gcry_cipher_map_name( algo.to_string().c_str() );
return gcry_cipher_algo;
}
static void
cipher_bench ( const char *algoname )
{
static int header_printed;
int algo;
gcry_cipher_hd_t hd;
int i;
int keylen, blklen;
char key[128];
char *outbuf, *buf;
char *raw_outbuf, *raw_buf;
size_t allocated_buflen, buflen;
int repetitions;
static struct { int mode; const char *name; int blocked; } modes[] = {
{ GCRY_CIPHER_MODE_ECB, " ECB/Stream", 1 },
{ GCRY_CIPHER_MODE_CBC, " CBC", 1 },
{ GCRY_CIPHER_MODE_CFB, " CFB", 0 },
{ GCRY_CIPHER_MODE_OFB, " OFB", 0 },
{ GCRY_CIPHER_MODE_CTR, " CTR", 0 },
{ GCRY_CIPHER_MODE_STREAM, "", 0 },
{0}
};
int modeidx;
gcry_error_t err = GPG_ERR_NO_ERROR;
if (!algoname)
{
for (i=1; i < 400; i++)
if ( !gcry_cipher_test_algo (i) )
cipher_bench (gcry_cipher_algo_name (i));
return;
}
if (large_buffers)
{
allocated_buflen = 1024 * 100;
repetitions = 10;
}
else
{
allocated_buflen = 1024;
repetitions = 1000;
}
repetitions *= cipher_repetitions;
raw_buf = gcry_xmalloc (allocated_buflen+15);
buf = (raw_buf
+ ((16 - ((size_t)raw_buf & 0x0f)) % buffer_alignment));
outbuf = raw_outbuf = gcry_xmalloc (allocated_buflen+15);
outbuf = (raw_outbuf
+ ((16 - ((size_t)raw_outbuf & 0x0f)) % buffer_alignment));
if (!header_printed)
{
if (cipher_repetitions != 1)
printf ("Running each test %d times.\n", cipher_repetitions);
printf ("%-12s", "");
for (modeidx=0; modes[modeidx].mode; modeidx++)
if (*modes[modeidx].name)
printf (" %-15s", modes[modeidx].name );
putchar ('\n');
printf ("%-12s", "");
for (modeidx=0; modes[modeidx].mode; modeidx++)
if (*modes[modeidx].name)
printf (" ---------------" );
putchar ('\n');
header_printed = 1;
}
algo = gcry_cipher_map_name (algoname);
if (!algo)
{
fprintf (stderr, PGM ": invalid cipher algorithm `%s'\n", algoname);
exit (1);
}
keylen = gcry_cipher_get_algo_keylen (algo);
if (!keylen)
{
fprintf (stderr, PGM ": failed to get key length for algorithm `%s'\n",
algoname);
exit (1);
}
if ( keylen > sizeof key )
{
fprintf (stderr, PGM ": algo %d, keylength problem (%d)\n",
algo, keylen );
exit (1);
}
for (i=0; i < keylen; i++)
key[i] = i + (clock () & 0xff);
blklen = gcry_cipher_get_algo_blklen (algo);
if (!blklen)
{
fprintf (stderr, PGM ": failed to get block length for algorithm `%s'\n",
algoname);
exit (1);
}
printf ("%-12s", gcry_cipher_algo_name (algo));
fflush (stdout);
for (modeidx=0; modes[modeidx].mode; modeidx++)
{
if ((blklen > 1 && modes[modeidx].mode == GCRY_CIPHER_MODE_STREAM)
| (blklen == 1 && modes[modeidx].mode != GCRY_CIPHER_MODE_STREAM))
continue;
for (i=0; i < sizeof buf; i++)
buf[i] = i;
err = gcry_cipher_open (&hd, algo, modes[modeidx].mode, 0);
if (err)
{
fprintf (stderr, PGM ": error opening cipher `%s'\n", algoname);
exit (1);
}
if (!cipher_with_keysetup)
{
err = gcry_cipher_setkey (hd, key, keylen);
if (err)
{
fprintf (stderr, "gcry_cipher_setkey failed: %s\n",
gpg_strerror (err));
gcry_cipher_close (hd);
exit (1);
}
}
buflen = allocated_buflen;
if (modes[modeidx].blocked)
buflen = (buflen / blklen) * blklen;
start_timer ();
for (i=err=0; !err && i < repetitions; i++)
{
if (cipher_with_keysetup)
{
err = gcry_cipher_setkey (hd, key, keylen);
if (err)
{
fprintf (stderr, "gcry_cipher_setkey failed: %s\n",
gpg_strerror (err));
gcry_cipher_close (hd);
exit (1);
}
}
err = gcry_cipher_encrypt ( hd, outbuf, buflen, buf, buflen);
}
stop_timer ();
printf (" %s", elapsed_time ());
fflush (stdout);
gcry_cipher_close (hd);
if (err)
{
fprintf (stderr, "gcry_cipher_encrypt failed: %s\n",
gpg_strerror (err) );
exit (1);
}
err = gcry_cipher_open (&hd, algo, modes[modeidx].mode, 0);
if (err)
{
fprintf (stderr, PGM ": error opening cipher `%s'/n", algoname);
exit (1);
}
if (!cipher_with_keysetup)
{
err = gcry_cipher_setkey (hd, key, keylen);
if (err)
{
fprintf (stderr, "gcry_cipher_setkey failed: %s\n",
gpg_strerror (err));
gcry_cipher_close (hd);
exit (1);
}
}
start_timer ();
for (i=err=0; !err && i < repetitions; i++)
{
if (cipher_with_keysetup)
{
err = gcry_cipher_setkey (hd, key, keylen);
if (err)
{
fprintf (stderr, "gcry_cipher_setkey failed: %s\n",
gpg_strerror (err));
gcry_cipher_close (hd);
exit (1);
}
}
err = gcry_cipher_decrypt ( hd, outbuf, buflen, buf, buflen);
}
stop_timer ();
printf (" %s", elapsed_time ());
fflush (stdout);
gcry_cipher_close (hd);
if (err)
{
fprintf (stderr, "gcry_cipher_decrypt failed: %s\n",
gpg_strerror (err) );
exit (1);
}
}
putchar ('\n');
gcry_free (raw_buf);
gcry_free (raw_outbuf);
}
static void
cipher_bench ( const char *algoname )
{
static int header_printed;
int algo;
gcry_cipher_hd_t hd;
int i;
int keylen, blklen;
char key[128];
char outbuf[1000], buf[1000];
size_t buflen;
static struct { int mode; const char *name; int blocked; } modes[] = {
{ GCRY_CIPHER_MODE_ECB, "ECB", 1 },
{ GCRY_CIPHER_MODE_CBC, "CBC", 1 },
{ GCRY_CIPHER_MODE_CFB, "CFB", 0 },
{ GCRY_CIPHER_MODE_CTR, "CTR", 0 },
{ GCRY_CIPHER_MODE_STREAM, "STREAM", 0 },
{0}
};
int modeidx;
gcry_error_t err = GPG_ERR_NO_ERROR;
if (!algoname)
{
for (i=1; i < 400; i++)
if ( !gcry_cipher_test_algo (i) )
cipher_bench (gcry_cipher_algo_name (i));
return;
}
if (!header_printed)
{
printf ("%-10s", "");
for (modeidx=0; modes[modeidx].mode; modeidx++)
printf (" %-15s", modes[modeidx].name );
putchar ('\n');
printf ("%-10s", "");
for (modeidx=0; modes[modeidx].mode; modeidx++)
printf (" ---------------" );
putchar ('\n');
header_printed = 1;
}
algo = gcry_cipher_map_name (algoname);
if (!algo)
{
fprintf (stderr, PGM ": invalid cipher algorithm `%s'\n", algoname);
exit (1);
}
keylen = gcry_cipher_get_algo_keylen (algo);
if (!keylen)
{
fprintf (stderr, PGM ": failed to get key length for algorithm `%s'\n",
algoname);
exit (1);
}
if ( keylen > sizeof key )
{
fprintf (stderr, PGM ": algo %d, keylength problem (%d)\n",
algo, keylen );
exit (1);
}
for (i=0; i < keylen; i++)
key[i] = i + (clock () & 0xff);
blklen = gcry_cipher_get_algo_blklen (algo);
if (!blklen)
{
fprintf (stderr, PGM ": failed to get block length for algorithm `%s'\n",
algoname);
exit (1);
}
printf ("%-10s", gcry_cipher_algo_name (algo));
fflush (stdout);
for (modeidx=0; modes[modeidx].mode; modeidx++)
{
if ((blklen > 1 && modes[modeidx].mode == GCRY_CIPHER_MODE_STREAM)
| (blklen == 1 && modes[modeidx].mode != GCRY_CIPHER_MODE_STREAM))
{
printf (" " );
continue;
}
for (i=0; i < sizeof buf; i++)
buf[i] = i;
err = gcry_cipher_open (&hd, algo, modes[modeidx].mode, 0);
if (err)
{
fprintf (stderr, PGM ": error opening cipher `%s'\n", algoname);
exit (1);
}
err = gcry_cipher_setkey (hd, key, keylen);
if (err)
{
fprintf (stderr, "gcry_cipher_setkey failed: %s\n",
gpg_strerror (err));
gcry_cipher_close (hd);
exit (1);
}
buflen = sizeof buf;
if (modes[modeidx].blocked)
buflen = (buflen / blklen) * blklen;
start_timer ();
for (i=err=0; !err && i < 1000; i++)
err = gcry_cipher_encrypt ( hd, outbuf, buflen, buf, buflen);
stop_timer ();
printf (" %s", elapsed_time ());
fflush (stdout);
gcry_cipher_close (hd);
if (err)
{
fprintf (stderr, "gcry_cipher_encrypt failed: %s\n",
gpg_strerror (err) );
exit (1);
}
err = gcry_cipher_open (&hd, algo, modes[modeidx].mode, 0);
if (err)
{
fprintf (stderr, PGM ": error opening cipher `%s'/n", algoname);
exit (1);
}
err = gcry_cipher_setkey (hd, key, keylen);
if (err)
{
fprintf (stderr, "gcry_cipher_setkey failed: %s\n",
gpg_strerror (err));
gcry_cipher_close (hd);
exit (1);
}
start_timer ();
for (i=err=0; !err && i < 1000; i++)
err = gcry_cipher_decrypt ( hd, outbuf, buflen, buf, buflen);
stop_timer ();
printf (" %s", elapsed_time ());
fflush (stdout);
gcry_cipher_close (hd);
if (err)
{
fprintf (stderr, "gcry_cipher_decrypt failed: %s\n",
gpg_strerror (err) );
exit (1);
}
}
putchar ('\n');
}
static gcry_cipher_hd_t
prepare_and_encode_pkcs8_cipher (GNode *asn, const gchar *password,
gsize n_password, gsize *n_block)
{
GNode *asn1_params = NULL;
gcry_cipher_hd_t cih;
guchar *salt;
gsize n_salt;
gcry_error_t gcry;
guchar *key, *iv;
gsize n_key;
int iterations;
init_quarks ();
/* Make sure the encryption algorithm works */
g_return_val_if_fail (gcry_cipher_algo_info (gcry_cipher_map_name (g_quark_to_string (OID_PKCS12_PBE_3DES_SHA1)),
GCRYCTL_TEST_ALGO, NULL, 0) == 0, NULL);
/* The encryption algorithm */
if(!egg_asn1x_set_oid_as_quark (egg_asn1x_node (asn, "encryptionAlgorithm", "algorithm", NULL),
OID_PKCS12_PBE_3DES_SHA1))
g_return_val_if_reached (NULL);
/* Randomize some input for the password based secret */
iterations = g_random_int_range (1000, 4096);
n_salt = 8;
salt = g_malloc (n_salt);
gcry_create_nonce (salt, n_salt);
/* Allocate space for the key and iv */
n_key = gcry_cipher_get_algo_keylen (GCRY_CIPHER_3DES);
*n_block = gcry_cipher_get_algo_blklen (GCRY_MD_SHA1);
g_return_val_if_fail (n_key && *n_block, NULL);
if (!egg_symkey_generate_pkcs12 (GCRY_CIPHER_3DES, GCRY_MD_SHA1,
password, n_password, salt,
sizeof (salt), iterations, &key, &iv))
g_return_val_if_reached (NULL);
/* Now write out the parameters */
asn1_params = egg_asn1x_create (pkix_asn1_tab, "pkcs-12-PbeParams");
g_return_val_if_fail (asn1_params, NULL);
egg_asn1x_set_string_as_raw (egg_asn1x_node (asn1_params, "salt", NULL), salt, n_salt, g_free);
egg_asn1x_set_integer_as_ulong (egg_asn1x_node (asn1_params, "iterations", NULL), iterations);
egg_asn1x_set_any_from (egg_asn1x_node (asn, "encryptionAlgorithm", "parameters", NULL), asn1_params);
/* Now make a cipher that matches what we wrote out */
gcry = gcry_cipher_open (&cih, GCRY_CIPHER_3DES, GCRY_CIPHER_MODE_CBC, 0);
g_return_val_if_fail (gcry == 0, NULL);
g_return_val_if_fail (cih, NULL);
gcry_cipher_setiv (cih, iv, *n_block);
gcry_cipher_setkey (cih, key, n_key);
g_free (iv);
egg_secure_free (key);
egg_asn1x_destroy (asn1_params);
return cih;
}
int main (int argc, char **argv) {
/*
Parse arguments
*/
if(opt_parse("usage: %s < filename > [options]", options, argv) == 0) {
opt_help(0, NULL);
}
/*
Read in password
*/
char *pass = NULL;
size_t passLen = 0;
ssize_t passRead;
char *fileName;
printf("Password: "******"libgcrypt version mismatch\n", stderr);
exit (2);
}
gcry_control(GCRYCTL_SUSPEND_SECMEM_WARN);
gcry_control(GCRYCTL_INIT_SECMEM, 131072, 0);
gcry_control(GCRYCTL_RESUME_SECMEM_WARN);
gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
/*
Key Generation
*/
char key[16] = "";
size_t keyLength = gcry_cipher_get_algo_keylen(GCRY_CIPHER);
const char *salt = "NaCl";
size_t saltLen = sizeof(salt);
unsigned long iterations = 4096;
gpg_error_t errStatus;
errStatus = gcry_kdf_derive(pass, passLen, GCRY_KDF_PBKDF2, GCRY_MD_SHA512, salt, saltLen, iterations, keyLength, key);
/*
Cipher Setup
*/
// printf("Key: %X\n", key);
puts(key);
const char* IV = "5844"; // const int IV = 5844;
const char *name = "aes128";
int algorithm = gcry_cipher_map_name(name);
size_t blockLength = gcry_cipher_get_algo_blklen(GCRY_CIPHER);
gcry_cipher_hd_t hand;
gcry_cipher_open(&hand, algorithm, GCRY_CIPHER_MODE_CBC, 0);
gcry_cipher_setkey(hand, key, keyLength);
gcry_cipher_setiv(hand, IV, blockLength);
char *buffer;
long len;
size_t macLen = 0;
/*
If the local flag is set then we encrypt the file locally
instead of sending it over the network
Otherwise we send the file over the network
*/
if (local == 1) {
/*
Open the file for reading and then copy to a buffer
*/
FILE *ifp = fopen(argv[1], "rb");
if(ifp == 0) {
printf("%s", "Could not open file");
return 1;
}
// Lets figure out how big the file is
fseek(ifp, 0L, SEEK_END);
len = ftell(ifp);
rewind(ifp);
// Allocate secure RAM for the buffer
buffer = gcry_calloc_secure(len, sizeof(char));
// Copy the input file to the buffer
fread(buffer, 1, len, ifp);
// Since we're running locally, the name of the output file is the same as the argument
// without the .gt
fileName = argv[1];
size_t inLen = strlen(fileName);
// End the filename by replacing the "." with a NULL char
fileName[inLen-3] = '\0';
fclose(ifp);
} else {
/*
Retrieve file from remote computer
Open a socket and listen for communication
*/
int sock;
int localSock;
struct sockaddr_in inPort;
inPort.sin_family = AF_INET;
inPort.sin_addr.s_addr = INADDR_ANY;
inPort.sin_port = htons(port);
sock = socket(AF_INET, SOCK_STREAM, 0);
if (sock == -1) {
printf("%s", "Could not open socket");
exit(1);
}
bind(sock, (struct sockaddr *) &inPort, sizeof(inPort));
listen(sock, 0);
printf("%s", "Waiting for connection...\n");
// Accepting the connection
localSock = accept(sock, NULL, NULL);
printf("%s", "Inbound file...\n");
// Allocate some memory for the buffer
// len+(160(len%16)) is so that the memory we allocate is divisible
// by the blocklength, which is 16
len = 4096L;
buffer = gcry_calloc_secure(len+(16-(len%16)), sizeof(char));
long dataRead = 0L;
int keepReading = 1;
// Let's figure out how much data we're getting
// If I were to do this part over, I would instead open two connections
// from techrypt- where the first connection sends the
// amount of data to be transmitted in the second connection
while (keepReading) {
dataRead = recv(localSock, buffer, len, MSG_PEEK);
if (dataRead == len) {
len = len * 2;
sleep(.5);
buffer = gcry_realloc(buffer, len);
keepReading = 1;
} else {
keepReading = 0;
}
}
// How much data did we read?
len = dataRead;
// Now lets actually store it in the buffer
dataRead = recv(localSock, buffer, len, 0);
// Output file name is the command line argument
fileName = argv[1];
close(sock);
/*
Setup the HMAC
*/
gcry_md_hd_t macHand;
macLen = gcry_md_get_algo_dlen(GCRY_MD_SHA512);
char *mac = gcry_calloc_secure(macLen, sizeof(char));
gcry_md_open(&macHand, GCRY_MD_SHA512, GCRY_MD_FLAG_HMAC);
gcry_md_setkey(macHand, key, keyLength);
// Generate the HMAC for the message we received
// Since we know there's a MAC of size macLen at the end
// we will only generate the hash based on the first
// len-macLen bytes
gcry_md_write(macHand, buffer, len-macLen);
mac = gcry_md_read(macHand, 0);
/*
Strip HMAC from buffer
*/
char *exMac = buffer+(len-macLen);
/*
Check HMAC against our HMAC
*/
// I think this may be exploitable with a strategically placed NULL
// The use of memcmp could fix this...if I have time I will replace and check
if(strncmp(mac, exMac, macLen) != 0) {
exit(62);
}
}
/*
Decrypt the buffer
*/
gcry_cipher_decrypt(hand, buffer, len, NULL, 0);
/*
Reverse padding algorithm
Strip the amount of bytes from the end of the file
determined by the contents of the last byte
This is why using PKCS7 was so useful
*/
char *padPtr = buffer+len-macLen-1;
int writeLen = len-macLen-(*padPtr);
/*
Write the buffer to a file
*/
FILE *ofp = fopen(fileName, "wb");
fwrite(buffer, 1, writeLen, ofp);
fclose(ofp);
return 0;
}
