int
_libssh2_rsa_sha1_sign(LIBSSH2_SESSION * session,
libssh2_dsa_ctx * rsactx,
const unsigned char *hash,
size_t hash_len,
unsigned char **signature, size_t *signature_len)
{
gcry_sexp_t sig_sexp;
gcry_sexp_t data;
int rc;
const char *tmp;
size_t size;
if (hash_len != SHA_DIGEST_LENGTH) {
return -1;
}
if (gcry_sexp_build(&data, NULL,
"(data (flags pkcs1) (hash sha1 %b))",
hash_len, hash)) {
return -1;
}
rc = gcry_pk_sign(&sig_sexp, data, rsactx);
gcry_sexp_release(data);
if (rc != 0) {
return -1;
}
data = gcry_sexp_find_token(sig_sexp, "s", 0);
if (!data) {
return -1;
}
tmp = gcry_sexp_nth_data(data, 1, &size);
if (!tmp) {
return -1;
}
if (tmp[0] == '\0') {
tmp++;
size--;
}
*signature = LIBSSH2_ALLOC(session, size);
memcpy(*signature, tmp, size);
*signature_len = size;
return rc;
}
static int
read_single_mpi( gcry_sexp_t s_key, const char * val, gcry_mpi_t * r_resarr )
{
gcry_sexp_t list;
if( !r_resarr )
return CDK_Inv_Value;
list = gcry_sexp_find_token( s_key, val, 0 );
if( list )
*r_resarr = gcry_sexp_nth_mpi( list, 1, 0 );
gcry_sexp_release( list );
return list? 0 : CDK_Gcry_Error;
}
static gcry_mpi_t
key_param_from_sexp (gcry_sexp_t sexp, const char *topname, const char *name)
{
gcry_sexp_t l1, l2;
gcry_mpi_t result;
l1 = gcry_sexp_find_token (sexp, topname, 0);
if (!l1)
return NULL;
l2 = gcry_sexp_find_token (l1, name, 0);
if (!l2)
{
gcry_sexp_release (l1);
return NULL;
}
result = gcry_sexp_nth_mpi (l2, 1, GCRYMPI_FMT_USG);
gcry_sexp_release (l2);
gcry_sexp_release (l1);
return result;
}
void
crypto_rsa_encrypt(int len, uint8 * in, uint8 * out, uint32 modulus_size, uint8 * modulus, uint8 * exponent)
{
/* GnuTLS do not expose raw RSA, so we use the underlying gcrypt lib instead */
ASSERT(modulus_size <= SEC_MAX_MODULUS_SIZE);
gcry_mpi_t m;
gcry_error_t rc = gcry_mpi_scan(&m, GCRYMPI_FMT_USG, modulus, modulus_size, NULL);
ASSERT(!rc);
gcry_mpi_t e;
rc = gcry_mpi_scan(&e, GCRYMPI_FMT_USG, exponent, SEC_EXPONENT_SIZE, NULL);
gcry_sexp_t publickey_sexp;
rc = gcry_sexp_build(&publickey_sexp, NULL, "(public-key(rsa(n%m)(e%m)))", m, e);
ASSERT(!rc);
gcry_mpi_release(m);
gcry_mpi_release(e);
gcry_mpi_t in_gcry;
rc = gcry_mpi_scan(&in_gcry, GCRYMPI_FMT_USG, in, len, NULL);
ASSERT(!rc);
gcry_sexp_t in_sexp;
rc = gcry_sexp_build(&in_sexp, NULL, "%m", in_gcry);
ASSERT(!rc);
gcry_sexp_t out_sexp;
rc = gcry_pk_encrypt(&out_sexp, in_sexp, publickey_sexp);
ASSERT(!rc);
gcry_sexp_t out_list_sexp;
out_list_sexp = gcry_sexp_find_token(out_sexp, "a", 0);
ASSERT(out_list_sexp);
gcry_mpi_t out_gcry = gcry_sexp_nth_mpi(out_list_sexp, 1, GCRYMPI_FMT_NONE);
ASSERT(out_gcry);
size_t s;
rc = gcry_mpi_print(GCRYMPI_FMT_USG, out, modulus_size, &s, out_gcry);
ASSERT(!rc);
ASSERT(s == modulus_size);
gcry_mpi_release(out_gcry);
gcry_sexp_release(out_list_sexp);
gcry_mpi_release(in_gcry);
gcry_sexp_release(out_sexp);
gcry_sexp_release(in_sexp);
gcry_sexp_release(publickey_sexp);
}
static void
get_dsa_key_fips186_with_seed_new (gcry_sexp_t *pkey, gcry_sexp_t *skey)
{
gcry_sexp_t key_spec, key, pub_key, sec_key;
int rc;
rc = gcry_sexp_new
(&key_spec,
"(genkey"
" (dsa"
" (nbits 4:1024)"
" (use-fips186)"
" (transient-key)"
" (derive-parms"
" (seed #0cb1990c1fd3626055d7a0096f8fa99807399871#))))",
0, 1);
if (rc)
die ("error creating S-expression: %s\n", gcry_strerror (rc));
rc = gcry_pk_genkey (&key, key_spec);
gcry_sexp_release (key_spec);
if (rc)
die ("error generating DSA key: %s\n", gcry_strerror (rc));
if (verbose > 1)
show_sexp ("generated DSA key (fips 186 with seed):\n", key);
pub_key = gcry_sexp_find_token (key, "public-key", 0);
if (!pub_key)
die ("public part missing in key\n");
sec_key = gcry_sexp_find_token (key, "private-key", 0);
if (!sec_key)
die ("private part missing in key\n");
gcry_sexp_release (key);
*pkey = pub_key;
*skey = sec_key;
}
void generate_key(rsa_packet * packet, char **public_key, char **private_key) {
gcry_error_t error;
int i;
// Generate a reduced strength (to save time) RSA key, 1024 bits long
// gcry_sexp_t params = sexp_new( "(genkey (rsa (transient-key) (nbits 3:512)))" );
gcry_sexp_t params = sexp_new( "(genkey (rsa (transient-key) (nbits 4:1024)))" );
gcry_sexp_t r_key;
if ((error = gcry_pk_genkey(&r_key, params))) {
printf("Error in gcry_pk_genkey(): %s\nSource: %s\n", gcry_strerror(error), gcry_strsource(error));
exit(1);
}
// Parse the S expression strings
gcry_sexp_t public_sexp = gcry_sexp_nth(r_key, 1);
gcry_sexp_t private_sexp = gcry_sexp_nth(r_key, 2);
gcry_sexp_t mod_sexp = gcry_sexp_cdr(gcry_sexp_find_token(private_sexp, "n", 1));
gcry_sexp_t priv_exp_sexp = gcry_sexp_cdr(gcry_sexp_find_token(private_sexp, "d", 1));
gcry_sexp_t pub_exp_sexp = gcry_sexp_cdr(gcry_sexp_find_token(public_sexp, "e", 1));
// Extract the raw data in MPI format
gcry_mpi_t mod_mpi, pubexp_mpi, privexp_mpi;
mod_mpi = gcry_sexp_nth_mpi(mod_sexp, 0, GCRYMPI_FMT_USG);
privexp_mpi = gcry_sexp_nth_mpi(priv_exp_sexp, 0, GCRYMPI_FMT_USG);
pubexp_mpi = gcry_sexp_nth_mpi(pub_exp_sexp, 0, GCRYMPI_FMT_USG);
//gcry_mpi_aprint(GCRYMPI_FMT_HEX, public_key, NULL, mod_mpi);
// Now pack it into unsigned char
gcry_mpi_print(GCRYMPI_FMT_USG, packet->mod, 256, &packet->mod_len, mod_mpi);
gcry_mpi_print(GCRYMPI_FMT_USG, packet->priv_exp, 256, &packet->priv_len, privexp_mpi);
gcry_mpi_print(GCRYMPI_FMT_USG, packet->pub_exp, 256, &packet->pub_len, pubexp_mpi);
// printf ("fmt: %i: %.*s\n", (int)len, (int) len, );
*public_key = sexp_string(public_sexp);
*private_key = sexp_string(private_sexp);
}
static void
extract_cmp_int (gcry_sexp_t sexp, const char *name, int expected)
{
gcry_sexp_t l1;
char *a;
l1 = gcry_sexp_find_token (sexp, name, 0);
a = gcry_sexp_nth_string (l1, 1);
if (!a)
fail ("parameter \"%s\" missing in key\n", name);
else if ( strtoul (a, NULL, 10) != expected )
fail ("parameter \"%s\" does not match expected value\n", name);
gcry_free (a);
gcry_sexp_release (l1);
}
static void
extract_cmp_mpi (gcry_sexp_t sexp, const char *name, const char *expected)
{
gcry_sexp_t l1;
gcry_mpi_t a, b;
l1 = gcry_sexp_find_token (sexp, name, 0);
a = gcry_sexp_nth_mpi (l1, 1, GCRYMPI_FMT_USG);
b = mpi_from_string (expected);
if (!a)
fail ("parameter \"%s\" missing in key\n", name);
else if ( gcry_mpi_cmp (a, b) )
fail ("parameter \"%s\" does not match expected value\n", name);
gcry_mpi_release (b);
gcry_mpi_release (a);
gcry_sexp_release (l1);
}
/**
* Duplicate the given public key
*
* @param key the public key to duplicate
* @return the duplicate key; NULL upon error
*/
struct GNUNET_CRYPTO_rsa_PublicKey *
GNUNET_CRYPTO_rsa_public_key_dup (const struct GNUNET_CRYPTO_rsa_PublicKey *key)
{
struct GNUNET_CRYPTO_rsa_PublicKey *dup;
gcry_sexp_t dup_sexp;
size_t erroff;
/* check if we really are exporting a public key */
dup_sexp = gcry_sexp_find_token (key->sexp, "public-key", 0);
GNUNET_assert (NULL != dup_sexp);
gcry_sexp_release (dup_sexp);
/* copy the sexp */
GNUNET_assert (0 == gcry_sexp_build (&dup_sexp, &erroff, "%S", key->sexp));
dup = GNUNET_new (struct GNUNET_CRYPTO_rsa_PublicKey);
dup->sexp = dup_sexp;
return dup;
}
static gpg_err_code_t
elg_generate_ext (int algo, unsigned int nbits, unsigned long evalue,
const gcry_sexp_t genparms,
gcry_mpi_t *skey, gcry_mpi_t **retfactors,
gcry_sexp_t *r_extrainfo)
{
gpg_err_code_t ec;
ELG_secret_key sk;
gcry_mpi_t xvalue = NULL;
gcry_sexp_t l1;
(void)algo;
(void)evalue;
(void)r_extrainfo;
if (genparms)
{
/* Parse the optional xvalue element. */
l1 = gcry_sexp_find_token (genparms, "xvalue", 0);
if (l1)
{
xvalue = gcry_sexp_nth_mpi (l1, 1, 0);
gcry_sexp_release (l1);
if (!xvalue)
return GPG_ERR_BAD_MPI;
}
}
if (xvalue)
{
ec = generate_using_x (&sk, nbits, xvalue, retfactors);
mpi_free (xvalue);
}
else
{
generate (&sk, nbits, retfactors);
ec = 0;
}
skey[0] = sk.p;
skey[1] = sk.g;
skey[2] = sk.y;
skey[3] = sk.x;
return ec;
}
/* Generate a private DSA key for a given account, storing it into a
* FILE*, and loading it into the given OtrlUserState. Overwrite any
* previously generated keys for that account in that OtrlUserState.
* The FILE* must be open for reading and writing. */
gcry_error_t otrl_privkey_generate_FILEp(OtrlUserState us, FILE *privf,
const char *accountname, const char *protocol)
{
gcry_error_t err;
gcry_sexp_t key, parms, privkey;
static const char *parmstr = "(genkey (dsa (nbits 4:1024)))";
OtrlPrivKey *p;
if (!privf) return gcry_error(GPG_ERR_NO_ERROR);
/* Create a DSA key */
err = gcry_sexp_new(&parms, parmstr, strlen(parmstr), 0);
if (err) {
return err;
}
err = gcry_pk_genkey(&key, parms);
gcry_sexp_release(parms);
if (err) {
return err;
}
/* Extract the privkey */
privkey = gcry_sexp_find_token(key, "private-key", 0);
gcry_sexp_release(key);
/* Output the other keys we know */
fprintf(privf, "(privkeys\n");
for (p=us->privkey_root; p; p=p->next) {
/* Skip this one if our new key replaces it */
if (!strcmp(p->accountname, accountname) &&
!strcmp(p->protocol, protocol)) {
continue;
}
account_write(privf, p->accountname, p->protocol, p->privkey);
}
account_write(privf, accountname, protocol, privkey);
gcry_sexp_release(privkey);
fprintf(privf, ")\n");
fseek(privf, 0, SEEK_SET);
return otrl_privkey_read_FILEp(us, privf);
}
static cdk_error_t
sexp_to_mpi (gcry_sexp_t sexp, const char *val, gcry_mpi_t *ret_buf)
{
gcry_sexp_t list;
if (!sexp || !val || !ret_buf)
return CDK_Inv_Value;
list = gcry_sexp_find_token (sexp, val, 0);
if (!list)
return CDK_Inv_Value;
*ret_buf = gcry_sexp_nth_mpi (list, 1, 0);
gcry_sexp_release (list);
if (! *ret_buf)
return CDK_Inv_Value;
return 0;
}
int p2p_encrypt(unsigned char *msg, size_t msglen, unsigned char *buf, size_t buflen, gcry_sexp_t r_key) {
gcry_sexp_t ciph, data;
size_t err;
gcry_sexp_build(&data, &err, "(data (flags pkcs1) (value %b))", msglen, msg);
gcry_pk_encrypt(&ciph, data, r_key);
gcry_sexp_release(data);
gcry_sexp_t a = gcry_sexp_find_token(ciph, "a", 0);
gcry_sexp_release(ciph);
gcry_sexp_t sexp_mpi = gcry_sexp_cdr(a);
gcry_sexp_release(a);
gcry_mpi_t data_mpi = gcry_sexp_nth_mpi(sexp_mpi, 0, GCRYMPI_FMT_USG);
gcry_mpi_print(GCRYMPI_FMT_PGP, buf, buflen, &err, data_mpi);
return err;
}
/*
* Extract an MPI from the given s-expression SEXP named NAME which is
* encoded using INFORMAT and store it in a newly allocated ssh_string
* encoded using OUTFORMAT.
*/
ssh_string ssh_sexp_extract_mpi(const gcry_sexp_t sexp,
const char *name,
enum gcry_mpi_format informat,
enum gcry_mpi_format outformat)
{
gpg_error_t err;
ssh_string result = NULL;
gcry_sexp_t fragment = NULL;
gcry_mpi_t mpi = NULL;
size_t size;
fragment = gcry_sexp_find_token(sexp, name, 0);
if (fragment == NULL) {
goto fail;
}
mpi = gcry_sexp_nth_mpi(fragment, 1, informat);
if (mpi == NULL) {
goto fail;
}
err = gcry_mpi_print(outformat, NULL, 0, &size, mpi);
if (err != 0) {
goto fail;
}
result = ssh_string_new(size);
if (result == NULL) {
goto fail;
}
err = gcry_mpi_print(outformat, ssh_string_data(result), size, NULL, mpi);
if (err != 0) {
ssh_string_burn(result);
ssh_string_free(result);
result = NULL;
goto fail;
}
fail:
gcry_sexp_release(fragment);
gcry_mpi_release(mpi);
return result;
}
static void
extract_cmp_data (gcry_sexp_t sexp, const char *name, const char *expected)
{
gcry_sexp_t l1;
const void *a;
size_t alen;
void *b;
size_t blen;
l1 = gcry_sexp_find_token (sexp, name, 0);
a = gcry_sexp_nth_data (l1, 1, &alen);
b = data_from_hex (expected, &blen);
if (!a)
fail ("parameter \"%s\" missing in key\n", name);
else if ( alen != blen || memcmp (a, b, alen) )
fail ("parameter \"%s\" does not match expected value\n", name);
gcry_free (b);
gcry_sexp_release (l1);
}
static libspectrum_error
get_mpi( gcry_mpi_t *mpi, gcry_sexp_t sexp, const char *token )
{
gcry_sexp_t pair;
pair = gcry_sexp_find_token( sexp, token, strlen( token ) );
if( !pair ) {
libspectrum_print_error( LIBSPECTRUM_ERROR_LOGIC,
"get_mpis: couldn't find '%s'", token );
return LIBSPECTRUM_ERROR_LOGIC;
}
*mpi = gcry_sexp_nth_mpi( pair, 1, GCRYMPI_FMT_STD );
if( !(*mpi) ) {
libspectrum_print_error( LIBSPECTRUM_ERROR_LOGIC,
"get_mpis: couldn't create MPI '%s'", token );
return LIBSPECTRUM_ERROR_LOGIC;
}
return LIBSPECTRUM_ERROR_NONE;
}
static char *
gcry_prikey2jwk (gcry_sexp_t * pubkey)
{
assert (NULL != pubkey);
gcry_error_t rc = -1;
gcry_sexp_t sexp_q;
gcry_mpi_t mpi_q;
unsigned char *raw_q;
size_t size_q;
size_t d_b64_len;
char *d_b64 = NULL;
if (NULL == (sexp_q = gcry_sexp_find_token(*pubkey, "d", 0)))
goto OUT;
if (NULL == (mpi_q = gcry_sexp_nth_mpi (sexp_q, 1, GCRYMPI_FMT_USG)))
goto FREE_Q;
rc = gcry_mpi_aprint(GCRYMPI_FMT_USG, &raw_q, &size_q, mpi_q);
if (rc)
goto FREE_MPI_Q;
if (0 == (d_b64_len = base64url_encode_alloc (raw_q, size_q, &d_b64)))
goto FREE_MPI_Q;
gcry_free (raw_q);
FREE_MPI_Q:
gcry_mpi_release (mpi_q);
FREE_Q:
gcry_sexp_release (sexp_q);
OUT:
return d_b64;
}
static int dsa_public_to_string(gcry_sexp_t key, ssh_buffer buffer) {
#elif defined HAVE_LIBCRYPTO
static int dsa_public_to_string(DSA *key, ssh_buffer buffer) {
#endif
ssh_string p = NULL;
ssh_string q = NULL;
ssh_string g = NULL;
ssh_string n = NULL;
int rc = -1;
#ifdef HAVE_LIBGCRYPT
const char *tmp = NULL;
size_t size;
gcry_sexp_t sexp;
sexp = gcry_sexp_find_token(key, "p", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp, 1, &size);
p = ssh_string_new(size);
if (p == NULL) {
goto error;
}
ssh_string_fill(p, (char *) tmp, size);
gcry_sexp_release(sexp);
sexp = gcry_sexp_find_token(key, "q", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp, 1, &size);
q = ssh_string_new(size);
if (q == NULL) {
goto error;
}
ssh_string_fill(q, (char *) tmp, size);
gcry_sexp_release(sexp);
sexp = gcry_sexp_find_token(key, "g", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp, 1, &size);
g = ssh_string_new(size);
if (g == NULL) {
goto error;
}
ssh_string_fill(g, (char *) tmp, size);
gcry_sexp_release(sexp);
sexp = gcry_sexp_find_token(key, "y", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp, 1, &size);
n = ssh_string_new(size);
if (n == NULL) {
goto error;
}
ssh_string_fill(n, (char *) tmp, size);
#elif defined HAVE_LIBCRYPTO
p = make_bignum_string(key->p);
q = make_bignum_string(key->q);
g = make_bignum_string(key->g);
n = make_bignum_string(key->pub_key);
if (p == NULL || q == NULL || g == NULL || n == NULL) {
goto error;
}
#endif /* HAVE_LIBCRYPTO */
if (buffer_add_ssh_string(buffer, p) < 0) {
goto error;
}
if (buffer_add_ssh_string(buffer, q) < 0) {
goto error;
}
if (buffer_add_ssh_string(buffer, g) < 0) {
goto error;
}
if (buffer_add_ssh_string(buffer, n) < 0) {
goto error;
}
rc = 0;
error:
#ifdef HAVE_LIBGCRYPT
gcry_sexp_release(sexp);
#endif
ssh_string_burn(p);
ssh_string_free(p);
ssh_string_burn(q);
ssh_string_free(q);
ssh_string_burn(g);
ssh_string_free(g);
ssh_string_burn(n);
ssh_string_free(n);
return rc;
#if defined(HAVE_LIBGCRYPT) || defined(HAVE_LIBCRYPTO)
}
/**
* @brief Make a public_key object out of a private_key object.
*
* @param[in] prv The private key to generate the public key.
*
* @returns The generated public key, NULL on error.
*
* @see publickey_to_string()
*/
ssh_public_key publickey_from_privatekey(ssh_private_key prv) {
ssh_public_key key = NULL;
#ifdef HAVE_LIBGCRYPT
gcry_sexp_t sexp;
const char *tmp = NULL;
size_t size;
ssh_string p = NULL;
ssh_string q = NULL;
ssh_string g = NULL;
ssh_string y = NULL;
ssh_string e = NULL;
ssh_string n = NULL;
#endif /* HAVE_LIBGCRYPT */
key = malloc(sizeof(struct ssh_public_key_struct));
if (key == NULL) {
return NULL;
}
ZERO_STRUCTP(key);
key->type = prv->type;
switch(key->type) {
case SSH_KEYTYPE_DSS:
#ifdef HAVE_LIBGCRYPT
sexp = gcry_sexp_find_token(prv->dsa_priv, "p", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp, 1, &size);
p = ssh_string_new(size);
if (p == NULL) {
goto error;
}
ssh_string_fill(p,(char *) tmp, size);
gcry_sexp_release(sexp);
sexp = gcry_sexp_find_token(prv->dsa_priv,"q",0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp,1,&size);
q = ssh_string_new(size);
if (q == NULL) {
goto error;
}
ssh_string_fill(q,(char *) tmp,size);
gcry_sexp_release(sexp);
sexp = gcry_sexp_find_token(prv->dsa_priv, "g", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp,1,&size);
g = ssh_string_new(size);
if (g == NULL) {
goto error;
}
ssh_string_fill(g,(char *) tmp,size);
gcry_sexp_release(sexp);
sexp = gcry_sexp_find_token(prv->dsa_priv,"y",0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp,1,&size);
y = ssh_string_new(size);
if (y == NULL) {
goto error;
}
ssh_string_fill(y,(char *) tmp,size);
gcry_sexp_release(sexp);
gcry_sexp_build(&key->dsa_pub, NULL,
"(public-key(dsa(p %b)(q %b)(g %b)(y %b)))",
ssh_string_len(p), ssh_string_data(p),
ssh_string_len(q), ssh_string_data(q),
ssh_string_len(g), ssh_string_data(g),
ssh_string_len(y), ssh_string_data(y));
ssh_string_burn(p);
ssh_string_free(p);
ssh_string_burn(q);
ssh_string_free(q);
ssh_string_burn(g);
ssh_string_free(g);
ssh_string_burn(y);
ssh_string_free(y);
#elif defined HAVE_LIBCRYPTO
key->dsa_pub = DSA_new();
if (key->dsa_pub == NULL) {
goto error;
}
key->dsa_pub->p = BN_dup(prv->dsa_priv->p);
key->dsa_pub->q = BN_dup(prv->dsa_priv->q);
key->dsa_pub->g = BN_dup(prv->dsa_priv->g);
key->dsa_pub->pub_key = BN_dup(prv->dsa_priv->pub_key);
if (key->dsa_pub->p == NULL ||
key->dsa_pub->q == NULL ||
key->dsa_pub->g == NULL ||
key->dsa_pub->pub_key == NULL) {
goto error;
}
#endif /* HAVE_LIBCRYPTO */
break;
case SSH_KEYTYPE_RSA:
case SSH_KEYTYPE_RSA1:
#ifdef HAVE_LIBGCRYPT
sexp = gcry_sexp_find_token(prv->rsa_priv, "n", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp, 1, &size);
n = ssh_string_new(size);
if (n == NULL) {
goto error;
}
ssh_string_fill(n, (char *) tmp, size);
gcry_sexp_release(sexp);
sexp = gcry_sexp_find_token(prv->rsa_priv, "e", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp, 1, &size);
e = ssh_string_new(size);
if (e == NULL) {
goto error;
}
ssh_string_fill(e, (char *) tmp, size);
gcry_sexp_release(sexp);
gcry_sexp_build(&key->rsa_pub, NULL,
"(public-key(rsa(n %b)(e %b)))",
ssh_string_len(n), ssh_string_data(n),
ssh_string_len(e), ssh_string_data(e));
if (key->rsa_pub == NULL) {
goto error;
}
ssh_string_burn(e);
ssh_string_free(e);
ssh_string_burn(n);
ssh_string_free(n);
#elif defined HAVE_LIBCRYPTO
key->rsa_pub = RSA_new();
if (key->rsa_pub == NULL) {
goto error;
}
key->rsa_pub->e = BN_dup(prv->rsa_priv->e);
key->rsa_pub->n = BN_dup(prv->rsa_priv->n);
if (key->rsa_pub->e == NULL ||
key->rsa_pub->n == NULL) {
goto error;
}
#endif
break;
default:
publickey_free(key);
return NULL;
}
key->type_c = ssh_type_to_char(prv->type);
return key;
error:
#ifdef HAVE_LIBGCRYPT
gcry_sexp_release(sexp);
ssh_string_burn(p);
ssh_string_free(p);
ssh_string_burn(q);
ssh_string_free(q);
ssh_string_burn(g);
ssh_string_free(g);
ssh_string_burn(y);
ssh_string_free(y);
ssh_string_burn(e);
ssh_string_free(e);
ssh_string_burn(n);
ssh_string_free(n);
#endif
publickey_free(key);
return NULL;
}
ssh_string ssh_encrypt_rsa1(ssh_session session, ssh_string data, ssh_public_key key) {
ssh_string str = NULL;
size_t len = ssh_string_len(data);
size_t size = 0;
#ifdef HAVE_LIBGCRYPT
const char *tmp = NULL;
gcry_sexp_t ret_sexp;
gcry_sexp_t data_sexp;
if (gcry_sexp_build(&data_sexp, NULL, "(data(flags pkcs1)(value %b))",
len, ssh_string_data(data))) {
ssh_set_error(session, SSH_FATAL, "RSA1 encrypt: libgcrypt error");
return NULL;
}
if (gcry_pk_encrypt(&ret_sexp, data_sexp, key->rsa_pub)) {
gcry_sexp_release(data_sexp);
ssh_set_error(session, SSH_FATAL, "RSA1 encrypt: libgcrypt error");
return NULL;
}
gcry_sexp_release(data_sexp);
data_sexp = gcry_sexp_find_token(ret_sexp, "a", 0);
if (data_sexp == NULL) {
ssh_set_error(session, SSH_FATAL, "RSA1 encrypt: libgcrypt error");
gcry_sexp_release(ret_sexp);
return NULL;
}
tmp = gcry_sexp_nth_data(data_sexp, 1, &size);
if (*tmp == 0) {
size--;
tmp++;
}
str = ssh_string_new(size);
if (str == NULL) {
ssh_set_error(session, SSH_FATAL, "Not enough space");
gcry_sexp_release(data_sexp);
gcry_sexp_release(ret_sexp);
return NULL;
}
ssh_string_fill(str, tmp, size);
gcry_sexp_release(data_sexp);
gcry_sexp_release(ret_sexp);
#elif defined HAVE_LIBCRYPTO
size = RSA_size(key->rsa_pub);
str = ssh_string_new(size);
if (str == NULL) {
ssh_set_error(session, SSH_FATAL, "Not enough space");
return NULL;
}
if (RSA_public_encrypt(len, ssh_string_data(data), ssh_string_data(str), key->rsa_pub,
RSA_PKCS1_PADDING) < 0) {
ssh_string_free(str);
return NULL;
}
#endif
return str;
}
STRING *signature_to_string(SIGNATURE *sign){
STRING *str;
STRING *rs;
#ifdef HAVE_LIBGCRYPT
const char *r,*s;
gcry_sexp_t sexp;
size_t size;
#elif defined HAVE_LIBCRYPTO
STRING *r,*s;
#endif
unsigned char buffer[40];
BUFFER *tmpbuf=buffer_new();
STRING *tmp;
tmp=string_from_char(ssh_type_to_char(sign->type));
buffer_add_ssh_string(tmpbuf,tmp);
free(tmp);
switch(sign->type){
case TYPE_DSS:
memset(buffer,0,40);
#ifdef HAVE_LIBGCRYPT
sexp=gcry_sexp_find_token(sign->dsa_sign,"r",0);
r=gcry_sexp_nth_data(sexp,1,&size);
if (*r == 0) /* libgcrypt put 0 when first bit is set */
{
size--;
r++;
}
memcpy(buffer,r + size - 20,20);
gcry_sexp_release(sexp);
sexp=gcry_sexp_find_token(sign->dsa_sign,"s",0);
s=gcry_sexp_nth_data(sexp,1,&size);
if (*s == 0)
{
size--;
s++;
}
memcpy(buffer+ 20, s + size - 20, 20);
gcry_sexp_release(sexp);
#elif defined HAVE_LIBCRYPTO
r=make_bignum_string(sign->dsa_sign->r);
s=make_bignum_string(sign->dsa_sign->s);
rs=string_new(40);
memcpy(buffer,r->string+string_len(r)-20,20);
memcpy(buffer+ 20, s->string + string_len(s) - 20, 20);
free(r);
free(s);
#endif
rs=string_new(40);
string_fill(rs,buffer,40);
buffer_add_ssh_string(tmpbuf,rs);
free(rs);
break;
case TYPE_RSA:
case TYPE_RSA1:
#ifdef HAVE_LIBGCRYPT
sexp=gcry_sexp_find_token(sign->rsa_sign,"s",0);
s=gcry_sexp_nth_data(sexp,1,&size);
if (*s == 0)
{
size--;
s++;
}
rs=string_new(size);
string_fill(rs,(char *)s,size);
buffer_add_ssh_string(tmpbuf,rs);
gcry_sexp_release(sexp);
free(rs);
#elif defined HAVE_LIBCRYPTO
buffer_add_ssh_string(tmpbuf,sign->rsa_sign);
#endif
break;
}
str=string_new(buffer_get_len(tmpbuf));
string_fill(str,buffer_get(tmpbuf),buffer_get_len(tmpbuf));
buffer_free(tmpbuf);
return str;
}
/** \brief Makes a PUBLIC_KEY object out of a PRIVATE_KEY object
* \param prv the Private key
* \returns the public key
* \see publickey_to_string()
*/
PUBLIC_KEY *publickey_from_privatekey(PRIVATE_KEY *prv){
PUBLIC_KEY *key=malloc(sizeof(PUBLIC_KEY));
#ifdef HAVE_LIBGCRYPT
gcry_sexp_t sexp;
const char *tmp;
size_t size;
STRING *p,*q,*g,*y,*e,*n;
#endif
key->type=prv->type;
switch(key->type){
case TYPE_DSS:
#ifdef HAVE_LIBGCRYPT
sexp=gcry_sexp_find_token(prv->dsa_priv,"p",0);
tmp=gcry_sexp_nth_data(sexp,1,&size);
p=string_new(size);
string_fill(p,(char *)tmp,size);
gcry_sexp_release(sexp);
sexp=gcry_sexp_find_token(prv->dsa_priv,"q",0);
tmp=gcry_sexp_nth_data(sexp,1,&size);
q=string_new(size);
string_fill(q,(char *)tmp,size);
gcry_sexp_release(sexp);
sexp=gcry_sexp_find_token(prv->dsa_priv,"g",0);
tmp=gcry_sexp_nth_data(sexp,1,&size);
g=string_new(size);
string_fill(g,(char *)tmp,size);
gcry_sexp_release(sexp);
sexp=gcry_sexp_find_token(prv->dsa_priv,"y",0);
tmp=gcry_sexp_nth_data(sexp,1,&size);
y=string_new(size);
string_fill(y,(char *)tmp,size);
gcry_sexp_release(sexp);
gcry_sexp_build(&key->dsa_pub,NULL,"(public-key(dsa(p %b)(q %b)(g %b)(y %b)))",string_len(p),p->string,string_len(q),q->string,string_len(g),g->string,string_len(y),y->string);
free(p);
free(q);
free(g);
free(y);
#elif defined HAVE_LIBCRYPTO
key->dsa_pub=DSA_new();
key->dsa_pub->p=BN_dup(prv->dsa_priv->p);
key->dsa_pub->q=BN_dup(prv->dsa_priv->q);
key->dsa_pub->pub_key=BN_dup(prv->dsa_priv->pub_key);
key->dsa_pub->g=BN_dup(prv->dsa_priv->g);
#endif
break;
case TYPE_RSA:
case TYPE_RSA1:
#ifdef HAVE_LIBGCRYPT
sexp=gcry_sexp_find_token(prv->rsa_priv,"n",0);
tmp=gcry_sexp_nth_data(sexp,1,&size);
n=string_new(size);
string_fill(n,(char *)tmp,size);
gcry_sexp_release(sexp);
sexp=gcry_sexp_find_token(prv->rsa_priv,"e",0);
tmp=gcry_sexp_nth_data(sexp,1,&size);
e=string_new(size);
string_fill(e,(char *)tmp,size);
gcry_sexp_release(sexp);
gcry_sexp_build(&key->rsa_pub,NULL,"(public-key(rsa(n %b)(e %b)))",string_len(n),n->string,string_len(e),e->string);
free(e);
free(n);
#elif defined HAVE_LIBCRYPTO
key->rsa_pub=RSA_new();
key->rsa_pub->e=BN_dup(prv->rsa_priv->e);
key->rsa_pub->n=BN_dup(prv->rsa_priv->n);
#endif
break;
}
key->type_c=ssh_type_to_char(prv->type);
return key;
}
/****************
* Emulate our old PK interface here - sometime in the future we might
* change the internal design to directly fit to libgcrypt.
*/
static int
_gnutls_pk_encrypt (int algo, mpi_t * resarr, mpi_t data,
mpi_t * pkey, int pkey_len)
{
gcry_sexp_t s_ciph, s_data, s_pkey;
int rc = -1;
/* make a sexp from pkey */
switch (algo)
{
case GCRY_PK_RSA:
if (pkey_len >= 2)
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(rsa(n%m)(e%m)))",
pkey[0], pkey[1]);
break;
default:
gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
if (rc != 0)
{
gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
/* put the data into a simple list */
if (gcry_sexp_build (&s_data, NULL, "%m", data))
{
gnutls_assert ();
gcry_sexp_release (s_pkey);
return GNUTLS_E_INTERNAL_ERROR;
}
/* pass it to libgcrypt */
rc = gcry_pk_encrypt (&s_ciph, s_data, s_pkey);
gcry_sexp_release (s_data);
gcry_sexp_release (s_pkey);
if (rc != 0)
{
gnutls_assert ();
return GNUTLS_E_PK_ENCRYPTION_FAILED;
}
else
{ /* add better error handling or make gnupg use S-Exp directly */
gcry_sexp_t list = gcry_sexp_find_token (s_ciph, "a", 0);
if (list == NULL)
{
gnutls_assert ();
gcry_sexp_release (s_ciph);
return GNUTLS_E_INTERNAL_ERROR;
}
resarr[0] = gcry_sexp_nth_mpi (list, 1, 0);
gcry_sexp_release (list);
if (resarr[0] == NULL)
{
gnutls_assert ();
gcry_sexp_release (s_ciph);
return GNUTLS_E_INTERNAL_ERROR;
}
}
gcry_sexp_release (s_ciph);
return rc;
}
static uint8_t*
sig2sigbuf (const gcry_sexp_t *sig, uint8_t **out, size_t *rs_len)
{
assert (NULL != sig);
assert (NULL != out);
gcry_error_t rc = -1;
gcry_sexp_t sexp_r, sexp_s;
gcry_mpi_t mpi_r, mpi_s;
unsigned char *raw_r, *raw_s;
size_t size_r, size_s;
uint8_t *rs;
if (NULL == (sexp_r = gcry_sexp_find_token(*sig, "r", 0)))
goto OUT;
if (NULL == (sexp_s = gcry_sexp_find_token(*sig, "s", 0)))
goto FREE_R;
if (NULL == (mpi_r = gcry_sexp_nth_mpi (sexp_r, 1, GCRYMPI_FMT_USG)))
goto FREE_S;
if (NULL == (mpi_s = gcry_sexp_nth_mpi (sexp_s, 1, GCRYMPI_FMT_USG)))
goto FREE_MPI_R;
rc = gcry_mpi_aprint(GCRYMPI_FMT_USG, &raw_r, &size_r, mpi_r);
if (rc)
goto FREE_MPI_S;
rc = gcry_mpi_aprint(GCRYMPI_FMT_USG, &raw_s, &size_s, mpi_s);
if (rc)
goto FREE_RAW_R;
rs = malloc (size_r+size_s);
memset (rs, 0, size_r+size_s);
memcpy (rs, raw_r, size_r);
memcpy (rs+size_r, raw_s, size_s);
*rs_len = size_r + size_s;
rc = 0;
gcry_free (raw_s);
FREE_RAW_R:
gcry_free (raw_r);
FREE_MPI_S:
gcry_mpi_release (mpi_s);
FREE_MPI_R:
gcry_mpi_release (mpi_r);
FREE_S:
gcry_sexp_release (sexp_s);
FREE_R:
gcry_sexp_release (sexp_r);
OUT:
if (rc == 0)
return rs;
else
return NULL;
}
/* A test based on bug 1594. */
static void
bug_1594 (void)
{
static char thing[] =
"(signature"
" (public-key"
" (rsa"
" (n #00A53A6B3A50BE571F805BD98ECE1FCE4CE291C3D4D3E971740E1EE6D447F526"
" 6AC8973DDC82F0ADD234CC82E0A0A3F48B81ACC8B038DB8ACC3E78DC2ED2642F"
" 6BA353FCA60F47C2801DEB477B37FB8B2F5508AA1C6D922780DB142DEA19B812"
" C4E64F1138AD3BD61C58DB2D2591BE0BF36A1AC588AA45763BCDFF581050ABA8"
" CA47BD9723ADD6A308AE28471EDD2B16D03C941D4F2B7E019C43AF8972880633"
" 54E97B7E19F1677D84B69A26B184A77B719DD72C48E0EE36107046F786566A9D"
" 13BAD724D6D78F24700FC22FC000E1B2A8C1B08ED62008395B0764CD9B55E80D"
" A0A2B61C698DC27EA98E68BB576ACFC2B91B4D7283E7D960948D049D6E3C4CB1"
" F489B460A120A4BB6C04A843FD3A67454136DE61CF68A927871EFFA9141BD372"
" A748593C703E0301F039A9E674C50301BFC385BABE5B154250E7D57B82DB31F1"
" E1AC696F870DCD8FE8DEC75608B988FCA3B484F1FD7755BF452F99597269AF02"
" E8AF87D0F93DB427291659183D077254C835BFB6DDFD87CD0B5E0738682FCD34"
" 923F22551F73944E6CBE3ED6879B4414676B5DA0F30ED21DFA12BD2230C3C5D2"
" EA116A3EFEB4AEC21C58E63FAFA549A63190F01859445E9B80F427B80FD4C884"
" 2AD41FE760A3E9DEDFB56CEBE8EA783838B2B392CACDDC760CCE212E388AFBC1"
" 95DC6D0ED87E9091F82A82CE372738C8DE8ABD76ACD06AC8B80AA0597162DF59"
" 67#)"
" (e #010001#))))";
gcry_sexp_t sig, pubkey, n, n_val;
info ("checking fix for bug 1594\n");
if (gcry_sexp_new (&sig, thing, 0, 1))
die ("scanning fixed string failed\n");
pubkey = gcry_sexp_find_token (sig, "public-key", 0);
gcry_sexp_release (sig);
if (!pubkey)
{
fail ("'public-key' token not found");
return;
}
n = gcry_sexp_find_token (pubkey, "n", 0);
if (!n)
{
fail ("'n' token not found");
gcry_sexp_release (pubkey);
return;
}
n_val = gcry_sexp_nth (n, 1);
/* Bug 1594 would require the following test:
* if (n_val)
* fail ("extracting 1-th of 'n' list did not fail");
* However, we meanwhile modified the S-expression functions to
* behave like Scheme to allow the access of any element of a list.
*/
if (!n_val)
fail ("extracting 1-th of 'n' list failed");
/*gcry_log_debugsxp ("1-th", n_val); => "(#00A5...#)" */
gcry_sexp_release (n_val);
n_val = gcry_sexp_nth (n, 2);
if (n_val)
fail ("extracting 2-th of 'n' list did not fail");
n_val = gcry_sexp_nth (n, 0);
if (!n_val)
fail ("extracting 0-th of 'n' list failed");
/*gcry_log_debugsxp ("0-th", n_val); => "(n)" */
if (gcry_sexp_nth (n_val, 1))
fail ("extracting 1-th of car of 'n' list did not fail");
gcry_sexp_release (n_val);
gcry_sexp_release (n);
gcry_sexp_release (pubkey);
}
static int rsa_public_to_string(gcry_sexp_t key, ssh_buffer buffer) {
#elif defined HAVE_LIBCRYPTO
static int rsa_public_to_string(RSA *key, ssh_buffer buffer) {
#endif
ssh_string e = NULL;
ssh_string n = NULL;
int rc = -1;
#ifdef HAVE_LIBGCRYPT
const char *tmp;
size_t size;
gcry_sexp_t sexp;
sexp = gcry_sexp_find_token(key, "n", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp, 1, &size);
n = ssh_string_new(size);
if (n == NULL) {
goto error;
}
ssh_string_fill(n, (char *) tmp, size);
gcry_sexp_release(sexp);
sexp = gcry_sexp_find_token(key, "e", 0);
if (sexp == NULL) {
goto error;
}
tmp = gcry_sexp_nth_data(sexp, 1, &size);
e = ssh_string_new(size);
if (e == NULL) {
goto error;
}
ssh_string_fill(e, (char *) tmp, size);
#elif defined HAVE_LIBCRYPTO
e = make_bignum_string(key->e);
n = make_bignum_string(key->n);
if (e == NULL || n == NULL) {
goto error;
}
#endif
if (buffer_add_ssh_string(buffer, e) < 0) {
goto error;
}
if (buffer_add_ssh_string(buffer, n) < 0) {
goto error;
}
rc = 0;
error:
#ifdef HAVE_LIBGCRYPT
gcry_sexp_release(sexp);
#endif
ssh_string_burn(e);
ssh_string_free(e);
ssh_string_burn(n);
ssh_string_free(n);
return rc;
#if defined(HAVE_LIBGCRYPT) || defined(HAVE_LIBCRYPTO)
}
/* Signature decoding functions */
ssh_string signature_to_string(SIGNATURE *sign) {
unsigned char buffer[40] = {0};
ssh_buffer tmpbuf = NULL;
ssh_string str = NULL;
ssh_string tmp = NULL;
ssh_string rs = NULL;
int rc = -1;
#ifdef HAVE_LIBGCRYPT
const char *r = NULL;
const char *s = NULL;
gcry_sexp_t sexp;
size_t size = 0;
#elif defined HAVE_LIBCRYPTO
ssh_string r = NULL;
ssh_string s = NULL;
#endif
tmpbuf = ssh_buffer_new();
if (tmpbuf == NULL) {
return NULL;
}
tmp = ssh_string_from_char(ssh_type_to_char(sign->type));
if (tmp == NULL) {
ssh_buffer_free(tmpbuf);
return NULL;
}
if (buffer_add_ssh_string(tmpbuf, tmp) < 0) {
ssh_buffer_free(tmpbuf);
ssh_string_free(tmp);
return NULL;
}
ssh_string_free(tmp);
switch(sign->type) {
case SSH_KEYTYPE_DSS:
#ifdef HAVE_LIBGCRYPT
sexp = gcry_sexp_find_token(sign->dsa_sign, "r", 0);
if (sexp == NULL) {
ssh_buffer_free(tmpbuf);
return NULL;
}
r = gcry_sexp_nth_data(sexp, 1, &size);
if (*r == 0) { /* libgcrypt put 0 when first bit is set */
size--;
r++;
}
memcpy(buffer, r + size - 20, 20);
gcry_sexp_release(sexp);
sexp = gcry_sexp_find_token(sign->dsa_sign, "s", 0);
if (sexp == NULL) {
ssh_buffer_free(tmpbuf);
return NULL;
}
s = gcry_sexp_nth_data(sexp,1,&size);
if (*s == 0) {
size--;
s++;
}
memcpy(buffer+ 20, s + size - 20, 20);
gcry_sexp_release(sexp);
#elif defined HAVE_LIBCRYPTO
r = make_bignum_string(sign->dsa_sign->r);
if (r == NULL) {
ssh_buffer_free(tmpbuf);
return NULL;
}
s = make_bignum_string(sign->dsa_sign->s);
if (s == NULL) {
ssh_buffer_free(tmpbuf);
ssh_string_free(r);
return NULL;
}
memcpy(buffer, (char *)ssh_string_data(r) + ssh_string_len(r) - 20, 20);
memcpy(buffer + 20, (char *)ssh_string_data(s) + ssh_string_len(s) - 20, 20);
ssh_string_free(r);
ssh_string_free(s);
#endif /* HAVE_LIBCRYPTO */
rs = ssh_string_new(40);
if (rs == NULL) {
ssh_buffer_free(tmpbuf);
return NULL;
}
ssh_string_fill(rs, buffer, 40);
rc = buffer_add_ssh_string(tmpbuf, rs);
ssh_string_free(rs);
if (rc < 0) {
ssh_buffer_free(tmpbuf);
return NULL;
}
break;
case SSH_KEYTYPE_RSA:
case SSH_KEYTYPE_RSA1:
#ifdef HAVE_LIBGCRYPT
sexp = gcry_sexp_find_token(sign->rsa_sign, "s", 0);
if (sexp == NULL) {
ssh_buffer_free(tmpbuf);
return NULL;
}
s = gcry_sexp_nth_data(sexp,1,&size);
if (*s == 0) {
size--;
s++;
}
rs = ssh_string_new(size);
if (rs == NULL) {
ssh_buffer_free(tmpbuf);
return NULL;
}
ssh_string_fill(rs, (char *) s, size);
rc = buffer_add_ssh_string(tmpbuf, rs);
gcry_sexp_release(sexp);
ssh_string_free(rs);
if (rc < 0) {
ssh_buffer_free(tmpbuf);
return NULL;
}
#elif defined HAVE_LIBCRYPTO
if (buffer_add_ssh_string(tmpbuf,sign->rsa_sign) < 0) {
ssh_buffer_free(tmpbuf);
return NULL;
}
#endif
break;
}
str = ssh_string_new(buffer_get_rest_len(tmpbuf));
if (str == NULL) {
ssh_buffer_free(tmpbuf);
return NULL;
}
ssh_string_fill(str, buffer_get_rest(tmpbuf), buffer_get_rest_len(tmpbuf));
ssh_buffer_free(tmpbuf);
return str;
}
void attack(int i, unsigned char *digest, int hash_len){
void* dsa_buf;
gcry_sexp_t new_dsa_key_pair;
gcry_sexp_t ciphertext , plaintext, ptx2, ctx2;
gcry_sexp_t r_param, r_tilda_param;
gcry_sexp_t s_param, s_tilda_param;
gcry_sexp_t g_param;
gcry_sexp_t p_param;
gcry_sexp_t q_param;
gcry_sexp_t m_param;
gcry_sexp_t y_param;
gcry_sexp_t x_param;
gcry_sexp_t misc_param;
gcry_error_t err;
gcry_mpi_t msg_digest, m;
gcry_mpi_t r , r_tilda;
gcry_mpi_t s , s_tilda;
gcry_mpi_t g;
gcry_mpi_t p;
gcry_mpi_t q;
gcry_mpi_t y;
gcry_mpi_t x;
retrieve_key_pair(files[i]);
//*************** CORRECT SIGNATURE ********************//
//20 is the mdlen of sha1 as specified in https://lists.gnupg.org/pipermail/gnupg-devel/2013-September/027916.html
//a well formatted number for the immaediate has an even number of digits
err = gcry_sexp_build(&plaintext, NULL, "(data (flags rfc6979) (hash %s %b))" , "sha1", hash_len , digest);
err = gcry_pk_sign(&ciphertext, plaintext, dsa_key_pair);
//now let's convert the s-expression representing r into an MPI in order
//to use it in the equation of the attack
//--------- CIPHERTEXT --------------
//intercepted during some sniffing...
r_param = gcry_sexp_find_token(ciphertext, "r", 0);
r = gcry_sexp_nth_mpi ( r_param , 1, GCRYMPI_FMT_USG);
s_param = gcry_sexp_find_token(ciphertext, "s", 0);
s = gcry_sexp_nth_mpi ( s_param , 1, GCRYMPI_FMT_USG);
//--------- PUB KEY --------------
g_param = gcry_sexp_find_token(dsa_key_pair, "g", 0);
g = gcry_sexp_nth_mpi ( g_param , 1, GCRYMPI_FMT_USG);
p_param = gcry_sexp_find_token(dsa_key_pair, "p", 0);
p = gcry_sexp_nth_mpi ( p_param , 1, GCRYMPI_FMT_USG);
q_param = gcry_sexp_find_token(dsa_key_pair, "q", 0);
q = gcry_sexp_nth_mpi ( q_param , 1, GCRYMPI_FMT_USG);
y_param = gcry_sexp_find_token(dsa_key_pair, "y", 0);
y = gcry_sexp_nth_mpi ( y_param , 1, GCRYMPI_FMT_USG);
x_param = gcry_sexp_find_token(dsa_key_pair, "x", 0);
x = gcry_sexp_nth_mpi ( x_param , 1, GCRYMPI_FMT_USG);
misc_param = gcry_sexp_find_token(dsa_key_pair, "misc-key-info", 0);
//*************** FAULTY SIGNATURE ********************//
err = gcry_sexp_build(&ptx2, NULL, "(data (flags rfc6979) (hash %s %b) (attack2_byte))" , "sha1", hash_len , digest);
err = gcry_pk_sign(&ctx2, ptx2, dsa_key_pair);
s_tilda_param = gcry_sexp_find_token(ctx2, "s", 0);
s_tilda = gcry_sexp_nth_mpi ( s_tilda_param , 1, GCRYMPI_FMT_USG);
r_tilda_param = gcry_sexp_find_token(ctx2, "r", 0);
r_tilda = gcry_sexp_nth_mpi ( r_tilda_param , 1, GCRYMPI_FMT_USG);
m_param = gcry_sexp_find_token(ptx2, "hash", 0);
m = gcry_sexp_nth_mpi ( m_param , 2, GCRYMPI_FMT_USG);
//NOW LET'S START THE ATTACK
unsigned long e = 0;
unsigned int qbits = mpi_get_nbits(q);
unsigned int pbits = mpi_get_nbits(p);
int hash_len_bits = hash_len*8;
gcry_mpi_t one = gcry_mpi_set_ui(NULL, 1);
gcry_mpi_t tmp = gcry_mpi_new(qbits);
gcry_mpi_t result = gcry_mpi_new(mpi_get_nbits(s));
gcry_mpi_invm(r,r,q); // r^-1
unsigned int j;
for(e = 0; e < qbits ; e++){
gcry_mpi_t empi = gcry_mpi_set_ui(NULL,e);
gcry_mpi_t twoi = gcry_mpi_new(e);
gcry_mpi_mul_2exp(empi, one, e); // twoi = 2^e
for( j=0; j< 256 ; j++){
gcry_mpi_t jmpi = gcry_mpi_set_ui(NULL,j);
gcry_mpi_mulm(twoi,jmpi,empi,q);
//retrieve k
gcry_mpi_mulm(tmp, s_tilda, twoi, q); // s_tilda*(2^e) modq q
gcry_mpi_subm(result, s_tilda, s, q); // s_tilda - s mod q
gcry_mpi_invm(result, result, q); // (s_tilda - s mod q)^-1
gcry_mpi_mulm(result,result, tmp, q); // s_tilda*(2^3) mod q)*(s_tilda - s mod q)^-1 === k
//retrieve x
gcry_mpi_mulm(result, s, result,q); // s*k mod q
gcry_mpi_subm(result, result, m, q); // s*k - m mod q
gcry_mpi_mulm(result, result,r,q); //(s*k -m)*r^-1 mod q
err = gcry_sexp_build(&new_dsa_key_pair,NULL,
"(key-data"
" (public-key"
" (dsa(p%m)(q%m)(g%m)(y%m)))"
" (private-key"
" (dsa(p%m)(q%m)(g%m)(y%m)(x%m))))",
p,q,g,y,p,q,g,y,result);
err = gcry_pk_sign(&ctx2, plaintext, new_dsa_key_pair);
err = gcry_pk_verify(ctx2, plaintext, dsa_key_pair);
if (err) {
//puts("gcrypt: verify failed");
continue;
}
else{
printf("\n[!!!]PRIVATE KEY %d %d BITS CRACKED!!\n" , pbits,qbits );
printf("[DBG] BYTE : %d * 2^%d FAULT: k-j*2^%d\n" , j , (int)e,(int)e); //DEBUG
DEBUG_MPI_PRINT(result,"X = ");
printf("\n");
return;
}
}
}
for(e = 0; e < qbits; e++){
gcry_mpi_t empi = gcry_mpi_set_ui(NULL,e);
gcry_mpi_t twoi = gcry_mpi_new(e);
gcry_mpi_mul_2exp(empi, one, e); // twoi = 2^e
for( j=0; j< 256 ; j++){
gcry_mpi_t jmpi = gcry_mpi_set_ui(NULL,j);
gcry_mpi_mulm(twoi,jmpi,empi,q);
//retrieve k
gcry_mpi_mulm(tmp, s_tilda, twoi, q); // s_tilda*(2^e) modq q
gcry_mpi_subm(result, s, s_tilda, q); // s_tilda - s mod q
gcry_mpi_invm(result, result, q); // (s_tilda - s mod q)^-1
gcry_mpi_mulm(result,result, tmp, q); // s_tilda*(2^3) mod q)*(s_tilda - s mod q)^-1 === k
//retrieve x
gcry_mpi_mulm(result, s, result,q); // s*k mod q
gcry_mpi_subm(result, result, m, q); // s*k - m mod q
gcry_mpi_mulm(result, result,r,q); //(s*k -m)*r^-1 mod q
err = gcry_sexp_build(&new_dsa_key_pair,NULL,
"(key-data"
" (public-key"
" (dsa(p%m)(q%m)(g%m)(y%m)))"
" (private-key"
" (dsa(p%m)(q%m)(g%m)(y%m)(x%m))))",
p,q,g,y,p,q,g,y,result);
err = gcry_pk_sign(&ctx2, plaintext, new_dsa_key_pair);
err = gcry_pk_verify(ctx2, plaintext, dsa_key_pair);
if (err) {
continue;
}
else{
printf("\n[!!!]PRIVATE KEY %d %d BITS CRACKED!!\n" , pbits,qbits );
printf("[DBG] BYTE : %d * 2^%d FAULT: k+j*2^%d\n" , j , (int)e,(int)e); //DEBUG
DEBUG_MPI_PRINT(result,"X = ");
printf("\n");
return;
}
}
}
}
/* in case of DSA puts into data, r,s
*/
static int
_gnutls_pk_sign (int algo, mpi_t * data, mpi_t hash, mpi_t * pkey,
int pkey_len)
{
gcry_sexp_t s_hash, s_key, s_sig;
int rc = -1;
/* make a sexp from pkey */
switch (algo)
{
case GCRY_PK_DSA:
if (pkey_len >= 5)
rc = gcry_sexp_build (&s_key, NULL,
"(private-key(dsa(p%m)(q%m)(g%m)(y%m)(x%m)))",
pkey[0], pkey[1], pkey[2], pkey[3], pkey[4]);
else
{
gnutls_assert ();
}
break;
case GCRY_PK_RSA:
if (pkey_len >= 6)
rc = gcry_sexp_build (&s_key, NULL,
"(private-key(rsa((n%m)(e%m)(d%m)(p%m)(q%m)(u%m))))",
pkey[0], pkey[1], pkey[2], pkey[3],
pkey[4], pkey[5]);
else
{
gnutls_assert ();
}
break;
default:
gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
if (rc != 0)
{
gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
/* put the data into a simple list */
if (gcry_sexp_build (&s_hash, NULL, "%m", hash))
{
gnutls_assert ();
return GNUTLS_E_INTERNAL_ERROR;
}
/* pass it to libgcrypt */
rc = gcry_pk_sign (&s_sig, s_hash, s_key);
gcry_sexp_release (s_hash);
gcry_sexp_release (s_key);
if (rc != 0)
{
gnutls_assert ();
return GNUTLS_E_PK_SIGN_FAILED;
}
else
{
gcry_sexp_t list;
if (algo == GCRY_PK_DSA)
{
list = gcry_sexp_find_token (s_sig, "r", 0);
if (list == NULL)
{
gnutls_assert ();
gcry_sexp_release (s_sig);
return GNUTLS_E_INTERNAL_ERROR;
}
data[0] = gcry_sexp_nth_mpi (list, 1, 0);
gcry_sexp_release (list);
list = gcry_sexp_find_token (s_sig, "s", 0);
if (list == NULL)
{
gnutls_assert ();
gcry_sexp_release (s_sig);
return GNUTLS_E_INTERNAL_ERROR;
}
data[1] = gcry_sexp_nth_mpi (list, 1, 0);
gcry_sexp_release (list);
}
else
{ /* GCRY_PK_RSA */
list = gcry_sexp_find_token (s_sig, "s", 0);
if (list == NULL)
{
gnutls_assert ();
gcry_sexp_release (s_sig);
return GNUTLS_E_INTERNAL_ERROR;
}
data[0] = gcry_sexp_nth_mpi (list, 1, 0);
gcry_sexp_release (list);
}
}
gcry_sexp_release (s_sig);
return 0;
}
/* fixme: we need better tests */
static void
basic (void)
{
int pass;
gcry_sexp_t sexp;
int idx;
char *secure_buffer;
size_t secure_buffer_len;
const char *string;
static struct {
const char *token;
const char *parm;
} values[] = {
{ "public-key", NULL },
{ "dsa", NULL },
{ "dsa", "p" },
{ "dsa", "y" },
{ "dsa", "q" },
{ "dsa", "g" },
{ NULL }
};
info ("doing some pretty pointless tests\n");
secure_buffer_len = 99;
secure_buffer = gcry_xmalloc_secure (secure_buffer_len);
memset (secure_buffer, 'G', secure_buffer_len);
for (pass=0;;pass++)
{
gcry_mpi_t m;
switch (pass)
{
case 0:
string = ("(public-key (dsa (p #41424344#) (y this_is_y) "
"(q #61626364656667#) (g %m)))");
m = gcry_mpi_set_ui (NULL, 42);
if ( gcry_sexp_build (&sexp, NULL, string, m ) )
{
gcry_mpi_release (m);
fail (" scanning `%s' failed\n", string);
return;
}
gcry_mpi_release (m);
break;
case 1:
string = ("(public-key (dsa (p #41424344#) (y this_is_y) "
"(q %b) (g %m)))");
m = gcry_mpi_set_ui (NULL, 42);
if ( gcry_sexp_build (&sexp, NULL, string,
15, "foo\0\x01\0x02789012345", m) )
{
gcry_mpi_release (m);
fail (" scanning `%s' failed\n", string);
return;
}
gcry_mpi_release (m);
break;
case 2:
string = ("(public-key (dsa (p #41424344#) (y silly_y_value) "
"(q %b) (g %m)))");
m = gcry_mpi_set_ui (NULL, 17);
if ( gcry_sexp_build (&sexp, NULL, string,
secure_buffer_len, secure_buffer, m) )
{
gcry_mpi_release (m);
fail (" scanning `%s' failed\n", string);
return;
}
gcry_mpi_release (m);
if (!gcry_is_secure (sexp))
fail ("gcry_sexp_build did not switch to secure memory\n");
break;
case 3:
{
gcry_sexp_t help_sexp;
if (gcry_sexp_new (&help_sexp,
"(foobar-parms (xp #1234#)(xq #03#))", 0, 1))
{
fail (" scanning fixed string failed\n");
return;
}
string = ("(public-key (dsa (p #41424344#) (parm %S) "
"(y dummy)(q %b) (g %m)))");
m = gcry_mpi_set_ui (NULL, 17);
if ( gcry_sexp_build (&sexp, NULL, string, help_sexp,
secure_buffer_len, secure_buffer, m) )
{
gcry_mpi_release (m);
fail (" scanning `%s' failed\n", string);
return;
}
gcry_mpi_release (m);
gcry_sexp_release (help_sexp);
}
break;
default:
return; /* Ready. */
}
/* now find something */
for (idx=0; values[idx].token; idx++)
{
const char *token = values[idx].token;
const char *parm = values[idx].parm;
gcry_sexp_t s1, s2;
gcry_mpi_t a;
const char *p;
size_t n;
s1 = gcry_sexp_find_token (sexp, token, strlen(token) );
if (!s1)
{
fail ("didn't found `%s'\n", token);
continue;
}
p = gcry_sexp_nth_data (s1, 0, &n);
if (!p)
{
gcry_sexp_release (s1);
fail ("no car for `%s'\n", token);
continue;
}
info ("car=`%.*s'\n", (int)n, p);
s2 = gcry_sexp_cdr (s1);
if (!s2)
{
gcry_sexp_release (s1);
fail ("no cdr for `%s'\n", token);
continue;
}
p = gcry_sexp_nth_data (s2, 0, &n);
gcry_sexp_release (s2);
if (p)
{
gcry_sexp_release (s1);
fail ("data at car of `%s'\n", token);
continue;
}
if (parm)
{
s2 = gcry_sexp_find_token (s1, parm, strlen (parm));
gcry_sexp_release (s1);
if (!s2)
{
fail ("didn't found `%s'\n", parm);
continue;
}
p = gcry_sexp_nth_data (s2, 0, &n);
if (!p)
{
gcry_sexp_release (s2);
fail("no car for `%s'\n", parm );
continue;
}
info ("car=`%.*s'\n", (int)n, p);
p = gcry_sexp_nth_data (s2, 1, &n);
if (!p)
{
gcry_sexp_release (s2);
fail("no cdr for `%s'\n", parm );
continue;
}
info ("cdr=`%.*s'\n", (int)n, p);
a = gcry_sexp_nth_mpi (s2, 0, GCRYMPI_FMT_USG);
gcry_sexp_release (s2);
if (!a)
{
fail("failed to cdr the mpi for `%s'\n", parm);
continue;
}
gcry_mpi_release (a);
}
else
gcry_sexp_release (s1);
}
gcry_sexp_release (sexp);
sexp = NULL;
}
gcry_free (secure_buffer);
}