46 |
static RC4_KEY rc4_decrypt_key; |
static RC4_KEY rc4_decrypt_key; |
47 |
static RC4_KEY rc4_encrypt_key; |
static RC4_KEY rc4_encrypt_key; |
48 |
static RSA *server_public_key; |
static RSA *server_public_key; |
49 |
|
static uint32 server_public_key_len; |
50 |
|
|
51 |
static uint8 sec_sign_key[16]; |
static uint8 sec_sign_key[16]; |
52 |
static uint8 sec_decrypt_key[16]; |
static uint8 sec_decrypt_key[16]; |
53 |
static uint8 sec_encrypt_key[16]; |
static uint8 sec_encrypt_key[16]; |
54 |
static uint8 sec_decrypt_update_key[16]; |
static uint8 sec_decrypt_update_key[16]; |
55 |
static uint8 sec_encrypt_update_key[16]; |
static uint8 sec_encrypt_update_key[16]; |
56 |
static uint8 sec_crypted_random[SEC_MODULUS_SIZE]; |
static uint8 sec_crypted_random[SEC_MAX_MODULUS_SIZE]; |
57 |
|
|
58 |
uint16 g_server_rdp_version = 0; |
uint16 g_server_rdp_version = 0; |
59 |
|
|
298 |
|
|
299 |
/* Perform an RSA public key encryption operation */ |
/* Perform an RSA public key encryption operation */ |
300 |
static void |
static void |
301 |
sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint8 * modulus, uint8 * exponent) |
sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint32 modulus_size, uint8 * modulus, |
302 |
|
uint8 * exponent) |
303 |
{ |
{ |
304 |
BN_CTX *ctx; |
BN_CTX *ctx; |
305 |
BIGNUM mod, exp, x, y; |
BIGNUM mod, exp, x, y; |
306 |
uint8 inr[SEC_MODULUS_SIZE]; |
uint8 inr[SEC_MAX_MODULUS_SIZE]; |
307 |
int outlen; |
int outlen; |
308 |
|
|
309 |
reverse(modulus, SEC_MODULUS_SIZE); |
reverse(modulus, modulus_size); |
310 |
reverse(exponent, SEC_EXPONENT_SIZE); |
reverse(exponent, SEC_EXPONENT_SIZE); |
311 |
memcpy(inr, in, len); |
memcpy(inr, in, len); |
312 |
reverse(inr, len); |
reverse(inr, len); |
317 |
BN_init(&x); |
BN_init(&x); |
318 |
BN_init(&y); |
BN_init(&y); |
319 |
|
|
320 |
BN_bin2bn(modulus, SEC_MODULUS_SIZE, &mod); |
BN_bin2bn(modulus, modulus_size, &mod); |
321 |
BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp); |
BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp); |
322 |
BN_bin2bn(inr, len, &x); |
BN_bin2bn(inr, len, &x); |
323 |
BN_mod_exp(&y, &x, &exp, &mod, ctx); |
BN_mod_exp(&y, &x, &exp, &mod, ctx); |
324 |
outlen = BN_bn2bin(&y, out); |
outlen = BN_bn2bin(&y, out); |
325 |
reverse(out, outlen); |
reverse(out, outlen); |
326 |
if (outlen < SEC_MODULUS_SIZE) |
if (outlen < modulus_size) |
327 |
memset(out + outlen, 0, SEC_MODULUS_SIZE - outlen); |
memset(out + outlen, 0, modulus_size - outlen); |
328 |
|
|
329 |
BN_free(&y); |
BN_free(&y); |
330 |
BN_clear_free(&x); |
BN_clear_free(&x); |
390 |
static void |
static void |
391 |
sec_establish_key(void) |
sec_establish_key(void) |
392 |
{ |
{ |
393 |
uint32 length = SEC_MODULUS_SIZE + SEC_PADDING_SIZE; |
uint32 length = server_public_key_len + SEC_PADDING_SIZE; |
394 |
uint32 flags = SEC_CLIENT_RANDOM; |
uint32 flags = SEC_CLIENT_RANDOM; |
395 |
STREAM s; |
STREAM s; |
396 |
|
|
397 |
s = sec_init(flags, 76); |
s = sec_init(flags, length + 4); |
398 |
|
|
399 |
out_uint32_le(s, length); |
out_uint32_le(s, length); |
400 |
out_uint8p(s, sec_crypted_random, SEC_MODULUS_SIZE); |
out_uint8p(s, sec_crypted_random, server_public_key_len); |
401 |
out_uint8s(s, SEC_PADDING_SIZE); |
out_uint8s(s, SEC_PADDING_SIZE); |
402 |
|
|
403 |
s_mark_end(s); |
s_mark_end(s); |
509 |
} |
} |
510 |
|
|
511 |
in_uint32_le(s, modulus_len); |
in_uint32_le(s, modulus_len); |
512 |
if (modulus_len != SEC_MODULUS_SIZE + SEC_PADDING_SIZE) |
modulus_len -= SEC_PADDING_SIZE; |
513 |
|
if ((modulus_len < 64) || (modulus_len > SEC_MAX_MODULUS_SIZE)) |
514 |
{ |
{ |
515 |
error("modulus len 0x%x\n", modulus_len); |
error("Bad server public key size (%u bits)\n", modulus_len * 8); |
516 |
return False; |
return False; |
517 |
} |
} |
518 |
|
|
519 |
in_uint8s(s, 8); /* modulus_bits, unknown */ |
in_uint8s(s, 8); /* modulus_bits, unknown */ |
520 |
in_uint8p(s, *exponent, SEC_EXPONENT_SIZE); |
in_uint8p(s, *exponent, SEC_EXPONENT_SIZE); |
521 |
in_uint8p(s, *modulus, SEC_MODULUS_SIZE); |
in_uint8p(s, *modulus, modulus_len); |
522 |
in_uint8s(s, SEC_PADDING_SIZE); |
in_uint8s(s, SEC_PADDING_SIZE); |
523 |
|
server_public_key_len = modulus_len; |
524 |
|
|
525 |
return s_check(s); |
return s_check(s); |
526 |
} |
} |
537 |
if (OBJ_obj2nid(cert->cert_info->key->algor->algorithm) == NID_md5WithRSAEncryption) |
if (OBJ_obj2nid(cert->cert_info->key->algor->algorithm) == NID_md5WithRSAEncryption) |
538 |
{ |
{ |
539 |
DEBUG_RDP5(("Re-setting algorithm type to RSA in server certificate\n")); |
DEBUG_RDP5(("Re-setting algorithm type to RSA in server certificate\n")); |
540 |
|
ASN1_OBJECT_free(cert->cert_info->key->algor->algorithm); |
541 |
cert->cert_info->key->algor->algorithm = OBJ_nid2obj(NID_rsaEncryption); |
cert->cert_info->key->algor->algorithm = OBJ_nid2obj(NID_rsaEncryption); |
542 |
} |
} |
543 |
epk = X509_get_pubkey(cert); |
epk = X509_get_pubkey(cert); |
547 |
return False; |
return False; |
548 |
} |
} |
549 |
|
|
550 |
server_public_key = (RSA *) epk->pkey.ptr; |
server_public_key = RSAPublicKey_dup((RSA *) epk->pkey.ptr); |
551 |
|
EVP_PKEY_free(epk); |
552 |
|
|
553 |
|
server_public_key_len = RSA_size(server_public_key); |
554 |
|
if ((server_public_key_len < 64) || (server_public_key_len > SEC_MAX_MODULUS_SIZE)) |
555 |
|
{ |
556 |
|
error("Bad server public key size (%u bits)\n", server_public_key_len * 8); |
557 |
|
return False; |
558 |
|
} |
559 |
|
|
560 |
return True; |
return True; |
561 |
} |
} |
693 |
MITM-attacks. |
MITM-attacks. |
694 |
*/ |
*/ |
695 |
|
|
696 |
|
X509_free(cacert); |
697 |
|
|
698 |
in_uint32_le(s, cert_len); |
in_uint32_le(s, cert_len); |
699 |
DEBUG_RDP5(("Certificate length is %d\n", cert_len)); |
DEBUG_RDP5(("Certificate length is %d\n", cert_len)); |
700 |
server_cert = d2i_X509(NULL, &(s->p), cert_len); |
server_cert = d2i_X509(NULL, &(s->p), cert_len); |
713 |
if (!sec_parse_x509_key(server_cert)) |
if (!sec_parse_x509_key(server_cert)) |
714 |
{ |
{ |
715 |
DEBUG_RDP5(("Didn't parse X509 correctly\n")); |
DEBUG_RDP5(("Didn't parse X509 correctly\n")); |
716 |
|
X509_free(server_cert); |
717 |
return False; |
return False; |
718 |
} |
} |
719 |
|
X509_free(server_cert); |
720 |
return True; /* There's some garbage here we don't care about */ |
return True; /* There's some garbage here we don't care about */ |
721 |
} |
} |
722 |
return s_check_end(s); |
return s_check_end(s); |
729 |
uint8 *server_random, *modulus, *exponent; |
uint8 *server_random, *modulus, *exponent; |
730 |
uint8 client_random[SEC_RANDOM_SIZE]; |
uint8 client_random[SEC_RANDOM_SIZE]; |
731 |
uint32 rc4_key_size; |
uint32 rc4_key_size; |
|
uint8 inr[SEC_MODULUS_SIZE]; |
|
732 |
|
|
733 |
if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, &modulus, &exponent)) |
if (!sec_parse_crypt_info(s, &rc4_key_size, &server_random, &modulus, &exponent)) |
734 |
{ |
{ |
737 |
} |
} |
738 |
|
|
739 |
DEBUG(("Generating client random\n")); |
DEBUG(("Generating client random\n")); |
|
/* Generate a client random, and hence determine encryption keys */ |
|
|
/* This is what the MS client do: */ |
|
|
memset(inr, 0, SEC_RANDOM_SIZE); |
|
|
/* *ARIGL!* Plaintext attack, anyone? |
|
|
I tried doing: |
|
|
generate_random(inr); |
|
|
..but that generates connection errors now and then (yes, |
|
|
"now and then". Something like 0 to 3 attempts needed before a |
|
|
successful connection. Nice. Not! |
|
|
*/ |
|
|
|
|
740 |
generate_random(client_random); |
generate_random(client_random); |
741 |
|
|
742 |
if (NULL != server_public_key) |
if (NULL != server_public_key) |
743 |
{ /* Which means we should use |
{ /* Which means we should use |
744 |
RDP5-style encryption */ |
RDP5-style encryption */ |
745 |
|
uint8 inr[SEC_MAX_MODULUS_SIZE]; |
746 |
|
uint32 padding_len = server_public_key_len - SEC_RANDOM_SIZE; |
747 |
|
|
748 |
memcpy(inr + SEC_RANDOM_SIZE, client_random, SEC_RANDOM_SIZE); |
/* This is what the MS client do: */ |
749 |
reverse(inr + SEC_RANDOM_SIZE, SEC_RANDOM_SIZE); |
memset(inr, 0, padding_len); |
750 |
|
/* *ARIGL!* Plaintext attack, anyone? |
751 |
|
I tried doing: |
752 |
|
generate_random(inr); |
753 |
|
..but that generates connection errors now and then (yes, |
754 |
|
"now and then". Something like 0 to 3 attempts needed before a |
755 |
|
successful connection. Nice. Not! |
756 |
|
*/ |
757 |
|
memcpy(inr + padding_len, client_random, SEC_RANDOM_SIZE); |
758 |
|
reverse(inr + padding_len, SEC_RANDOM_SIZE); |
759 |
|
|
760 |
RSA_public_encrypt(SEC_MODULUS_SIZE, |
RSA_public_encrypt(server_public_key_len, |
761 |
inr, sec_crypted_random, server_public_key, RSA_NO_PADDING); |
inr, sec_crypted_random, server_public_key, RSA_NO_PADDING); |
762 |
|
|
763 |
reverse(sec_crypted_random, SEC_MODULUS_SIZE); |
reverse(sec_crypted_random, server_public_key_len); |
764 |
|
|
765 |
|
RSA_free(server_public_key); |
766 |
|
server_public_key = NULL; |
767 |
} |
} |
768 |
else |
else |
769 |
{ /* RDP4-style encryption */ |
{ /* RDP4-style encryption */ |
770 |
sec_rsa_encrypt(sec_crypted_random, |
sec_rsa_encrypt(sec_crypted_random, |
771 |
client_random, SEC_RANDOM_SIZE, modulus, exponent); |
client_random, SEC_RANDOM_SIZE, server_public_key_len, modulus, |
772 |
|
exponent); |
773 |
} |
} |
774 |
sec_generate_keys(client_random, server_random, rc4_key_size); |
sec_generate_keys(client_random, server_random, rc4_key_size); |
775 |
} |
} |