[client] switch to nettle and gmp for RSA EME-OAEP support

Fixes #68
This commit is contained in:
Geoffrey McRae 2018-05-22 15:36:36 +10:00
parent ceac6a60e6
commit 9b0f974648
2 changed files with 140 additions and 49 deletions

View File

@ -9,11 +9,12 @@ CFLAGS += -Wfatal-errors
LIBS = sdl2 SDL2_ttf gl glu libssl openssl spice-protocol fontconfig x11 libconfig
#LIBS += gnutls
#CFLAGS += -D USE_GNUTLS
LIBS += nettle hogweed
CFLAGS += -D USE_NETTLE
LDFLAGS += -lgmp
LIBS += libssl openssl
CFLAGS += -D USE_OPENSSL
#LIBS += libssl openssl
#CFLAGS += -D USE_OPENSSL
CFLAGS += $(shell pkg-config --cflags $(LIBS))
LDFLAGS += $(shell pkg-config --libs $(LIBS))

View File

@ -21,11 +21,12 @@ Place, Suite 330, Boston, MA 02111-1307 USA
#include "debug.h"
#include <spice/protocol.h>
#include <malloc.h>
#include <string.h>
#if defined(USE_OPENSSL) && defined(USE_GNUTLS)
#if defined(USE_OPENSSL) && defined(USE_NETTLE)
#error "USE_OPENSSL and USE_GNUTLS are both defined"
#elif !defined(USE_OPENSSL) && !defined(USE_GNUTLS)
#elif !defined(USE_OPENSSL) && !defined(USE_NETTLE)
#error "One of USE_OPENSSL or USE_GNUTLS must be defined"
#endif
@ -35,13 +36,101 @@ Place, Suite 330, Boston, MA 02111-1307 USA
#include <openssl/x509.h>
#endif
#if defined(USE_GNUTLS)
#include <gnutls/gnutls.h>
#include <gnutls/abstract.h>
#if defined(USE_NETTLE)
#include <stdlib.h>
#include <nettle/asn1.h>
#include <nettle/sha1.h>
#include <nettle/rsa.h>
#include <gmp.h>
#define KEY_SIZE (1024 / 8)
#define SHA1_HASH_LEN 20
#endif
#if defined(USE_NETTLE)
/* the below OAEP implementation is derived from the FreeTDS project */
static void memxor(uint8_t * a, const uint8_t * b, const unsigned int len)
{
for(unsigned int i = 0; i < len; ++i)
a[i] = a[i] ^ b[i];
}
static void sha1(uint8_t * hash, const uint8_t *data, unsigned int len)
{
struct sha1_ctx ctx;
sha1_init(&ctx);
sha1_update(&ctx, len, data);
sha1_digest(&ctx, SHA1_HASH_LEN, hash);
}
static void oaep_mask(uint8_t * dest, size_t dest_len, const uint8_t * mask, size_t mask_len)
{
uint8_t hash[SHA1_HASH_LEN];
uint8_t seed[mask_len + 4 ];
memcpy(seed, mask, mask_len);
for(unsigned int n = 0;; ++n)
{
(seed+mask_len)[0] = n >> 24;
(seed+mask_len)[1] = n >> 16;
(seed+mask_len)[2] = n >> 8;
(seed+mask_len)[3] = n >> 0;
sha1(hash, seed, sizeof(seed));
if (dest_len <= SHA1_HASH_LEN)
{
memxor(dest, hash, dest_len);
break;
}
memxor(dest, hash, SHA1_HASH_LEN);
dest += SHA1_HASH_LEN;
dest_len -= SHA1_HASH_LEN;
}
}
static bool oaep_pad(mpz_t m, unsigned int key_size, const uint8_t * message, unsigned int len)
{
if (len + SHA1_HASH_LEN * 2 + 2 > key_size)
{
DEBUG_ERROR("Message too long");
return false;
}
struct
{
uint8_t all[1];
uint8_t ros[SHA1_HASH_LEN];
uint8_t db [key_size - SHA1_HASH_LEN - 1];
} em;
memset(&em, 0, sizeof(em));
sha1(em.db, (uint8_t *)"", 0);
em.all[key_size - len - 1] = 0x1;
memcpy(em.all + (key_size - len), message, len);
/* we are not too worried about randomness since we are just making a local
* connection, should anyone use this code outside of LookingGlass please be
* sure to use something better such as `gnutls_rnd` */
for(int i = 0; i < SHA1_HASH_LEN; ++i)
em.ros[i] = rand() % 255;
const int db_len = key_size - SHA1_HASH_LEN - 1;
oaep_mask(em.db , db_len , em.ros, SHA1_HASH_LEN);
oaep_mask(em.ros, SHA1_HASH_LEN, em.db , db_len );
nettle_mpz_set_str_256_u(m, key_size, em.all);
return true;
}
#endif
bool spice_rsa_encrypt_password(uint8_t * pub_key, char * password, struct spice_password * result)
{
result->size = 0;
result->data = NULL;
#if defined(USE_OPENSSL)
BIO *bioKey = BIO_new(BIO_s_mem());
if (!bioKey)
@ -80,59 +169,60 @@ bool spice_rsa_encrypt_password(uint8_t * pub_key, char * password, struct spice
return true;
#endif
#if defined(USE_GNUTLS)
const gnutls_datum_t pubData =
{
.data = (void *)reply.pub_key,
.size = SPICE_TICKET_PUBKEY_BYTES
};
#if defined(USE_NETTLE)
struct asn1_der_iterator der;
struct asn1_der_iterator j;
struct rsa_public_key pub;
gnutls_pubkey_t pubkey;
if (gnutls_pubkey_init(&pubkey) < 0)
if (asn1_der_iterator_first(&der, SPICE_TICKET_PUBKEY_BYTES, pub_key) == ASN1_ITERATOR_CONSTRUCTED
&& der.type == ASN1_SEQUENCE
&& asn1_der_decode_constructed_last(&der) == ASN1_ITERATOR_CONSTRUCTED
&& der.type == ASN1_SEQUENCE
&& asn1_der_decode_constructed(&der, &j) == ASN1_ITERATOR_PRIMITIVE
&& j.type == ASN1_IDENTIFIER
&& asn1_der_iterator_next(&der) == ASN1_ITERATOR_PRIMITIVE
&& der.type == ASN1_BITSTRING
&& asn1_der_decode_bitstring_last(&der))
{
DEBUG_ERROR("gnutls_pubkey_init failed");
if (j.length != 9)
{
DEBUG_ERROR("Invalid key, not RSA");
return false;
}
if (gnutls_pubkey_import(pubkey, &pubData, GNUTLS_X509_FMT_DER) < 0)
if (asn1_der_iterator_next(&j) == ASN1_ITERATOR_PRIMITIVE
&& j.type == ASN1_NULL
&& j.length == 0
&& asn1_der_iterator_next(&j) == ASN1_ITERATOR_END)
{
gnutls_pubkey_deinit(pubkey);
DEBUG_ERROR("gnutls_pubkey_import failed");
rsa_public_key_init(&pub);
if (!rsa_public_key_from_der_iterator(&pub, 0, &der))
{
DEBUG_ERROR("Unable to load public key from DER iterator");
rsa_public_key_clear(&pub);
return false;
}
const gnutls_datum_t input =
{
.data = (void *)spice.password,
.size = strlen(spice.password) + 1
};
gnutls_datum_t out;
if (gnutls_pubkey_encrypt_data(pubkey, 0, &input, &out) < 0)
{
gnutls_pubkey_deinit(pubkey);
DEBUG_ERROR("gnutls_pubkey_encrypt_data failed");
return false;
}
}
result->size = out.size;
result->data = out.data;
mpz_t p;
mpz_init(p);
oaep_pad(p, pub.size, (uint8_t *)password, strlen(password)+1);
mpz_powm(p, p, pub.e, pub.n);
gnutls_pubkey_deinit(pubkey);
result->size = pub.size;
result->data = malloc(pub.size);
nettle_mpz_get_str_256(pub.size, (uint8_t *)result->data, p);
rsa_public_key_clear(&pub);
mpz_clear(p);
return true;
#endif
}
void spice_rsa_free_password(struct spice_password * pass)
{
#if defined(USE_OPENSSL)
free(pass->data);
#endif
#if defined(USE_GNUTLS)
gnutls_free(pass->data);
#endif
pass->size = 0;
pass->data = NULL;
}