--- /dev/null
+/* -*- c-basic-offset: 8 -*-
+ rdesktop: A Remote Desktop Protocol client.
+ Protocol services - RDP encryption and licensing
+ Copyright (C) Matthew Chapman 1999-2005
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "rdesktop.h"
+#include <string.h>
+
+// TODO: remove dependency on OpenSSL
+#include <openssl/rc4.h>
+#include <openssl/md5.h>
+#include <openssl/sha.h>
+#include <openssl/bn.h>
+#include <openssl/x509v3.h>
+
+/*
+ * I believe this is based on SSLv3 with the following differences:
+ * MAC algorithm (5.2.3.1) uses only 32-bit length in place of seq_num/type/length fields
+ * MAC algorithm uses SHA1 and MD5 for the two hash functions instead of one or other
+ * key_block algorithm (6.2.2) uses 'X', 'YY', 'ZZZ' instead of 'A', 'BB', 'CCC'
+ * key_block partitioning is different (16 bytes each: MAC secret, decrypt key, encrypt key)
+ * encryption/decryption keys updated every 4096 packets
+ * See http://wp.netscape.com/eng/ssl3/draft302.txt
+ */
+
+/*
+ * 48-byte transformation used to generate master secret (6.1) and key material (6.2.2).
+ * Both SHA1 and MD5 algorithms are used.
+ */
+void
+sec_hash_48(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2, uint8 salt)
+{
+ uint8 shasig[20];
+ uint8 pad[4];
+ SHA_CTX sha;
+ MD5_CTX md5;
+ int i;
+
+ for (i = 0; i < 3; i++)
+ {
+ memset(pad, salt + i, i + 1);
+
+ SHA1_Init(&sha);
+ SHA1_Update(&sha, pad, i + 1);
+ SHA1_Update(&sha, in, 48);
+ SHA1_Update(&sha, salt1, 32);
+ SHA1_Update(&sha, salt2, 32);
+ SHA1_Final(shasig, &sha);
+
+ MD5_Init(&md5);
+ MD5_Update(&md5, in, 48);
+ MD5_Update(&md5, shasig, 20);
+ MD5_Final(&out[i * 16], &md5);
+ }
+}
+
+/*
+ * 16-byte transformation used to generate export keys (6.2.2).
+ */
+void
+sec_hash_16(uint8 * out, uint8 * in, uint8 * salt1, uint8 * salt2)
+{
+ MD5_CTX md5;
+
+ MD5_Init(&md5);
+ MD5_Update(&md5, in, 16);
+ MD5_Update(&md5, salt1, 32);
+ MD5_Update(&md5, salt2, 32);
+ MD5_Final(out, &md5);
+}
+
+/* Reduce key entropy from 64 to 40 bits */
+static void
+sec_make_40bit(uint8 * key)
+{
+ key[0] = 0xd1;
+ key[1] = 0x26;
+ key[2] = 0x9e;
+}
+
+/* Generate encryption keys given client and server randoms */
+static void
+sec_generate_keys(RDPCLIENT * This, uint8 * client_random, uint8 * server_random, int rc4_key_size)
+{
+ uint8 pre_master_secret[48];
+ uint8 master_secret[48];
+ uint8 key_block[48];
+
+ /* Construct pre-master secret */
+ memcpy(pre_master_secret, client_random, 24);
+ memcpy(pre_master_secret + 24, server_random, 24);
+
+ /* Generate master secret and then key material */
+ sec_hash_48(master_secret, pre_master_secret, client_random, server_random, 'A');
+ sec_hash_48(key_block, master_secret, client_random, server_random, 'X');
+
+ /* First 16 bytes of key material is MAC secret */
+ memcpy(This->secure.sign_key, key_block, 16);
+
+ /* Generate export keys from next two blocks of 16 bytes */
+ sec_hash_16(This->secure.decrypt_key, &key_block[16], client_random, server_random);
+ sec_hash_16(This->secure.encrypt_key, &key_block[32], client_random, server_random);
+
+ if (rc4_key_size == 1)
+ {
+ DEBUG(("40-bit encryption enabled\n"));
+ sec_make_40bit(This->secure.sign_key);
+ sec_make_40bit(This->secure.decrypt_key);
+ sec_make_40bit(This->secure.encrypt_key);
+ This->secure.rc4_key_len = 8;
+ }
+ else
+ {
+ DEBUG(("rc_4_key_size == %d, 128-bit encryption enabled\n", rc4_key_size));
+ This->secure.rc4_key_len = 16;
+ }
+
+ /* Save initial RC4 keys as update keys */
+ memcpy(This->secure.decrypt_update_key, This->secure.decrypt_key, 16);
+ memcpy(This->secure.encrypt_update_key, This->secure.encrypt_key, 16);
+
+ /* Initialise RC4 state arrays */
+ RC4_set_key(&This->secure.rc4_decrypt_key, This->secure.rc4_key_len, This->secure.decrypt_key);
+ RC4_set_key(&This->secure.rc4_encrypt_key, This->secure.rc4_key_len, This->secure.encrypt_key);
+}
+
+static const uint8 pad_54[40] = {
+ 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
+ 54, 54, 54,
+ 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
+ 54, 54, 54
+};
+
+static const uint8 pad_92[48] = {
+ 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
+ 92, 92, 92, 92, 92, 92, 92,
+ 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
+ 92, 92, 92, 92, 92, 92, 92
+};
+
+/* Output a uint32 into a buffer (little-endian) */
+void
+buf_out_uint32(uint8 * buffer, uint32 value)
+{
+ buffer[0] = (value) & 0xff;
+ buffer[1] = (value >> 8) & 0xff;
+ buffer[2] = (value >> 16) & 0xff;
+ buffer[3] = (value >> 24) & 0xff;
+}
+
+/* Generate a MAC hash (5.2.3.1), using a combination of SHA1 and MD5 */
+void
+sec_sign(uint8 * signature, int siglen, uint8 * session_key, int keylen, uint8 * data, int datalen)
+{
+ uint8 shasig[20];
+ uint8 md5sig[16];
+ uint8 lenhdr[4];
+ SHA_CTX sha;
+ MD5_CTX md5;
+
+ buf_out_uint32(lenhdr, datalen);
+
+ SHA1_Init(&sha);
+ SHA1_Update(&sha, session_key, keylen);
+ SHA1_Update(&sha, pad_54, 40);
+ SHA1_Update(&sha, lenhdr, 4);
+ SHA1_Update(&sha, data, datalen);
+ SHA1_Final(shasig, &sha);
+
+ MD5_Init(&md5);
+ MD5_Update(&md5, session_key, keylen);
+ MD5_Update(&md5, pad_92, 48);
+ MD5_Update(&md5, shasig, 20);
+ MD5_Final(md5sig, &md5);
+
+ memcpy(signature, md5sig, siglen);
+}
+
+/* Update an encryption key */
+static void
+sec_update(RDPCLIENT * This, uint8 * key, uint8 * update_key)
+{
+ uint8 shasig[20];
+ SHA_CTX sha;
+ MD5_CTX md5;
+ RC4_KEY update;
+
+ SHA1_Init(&sha);
+ SHA1_Update(&sha, update_key, This->secure.rc4_key_len);
+ SHA1_Update(&sha, pad_54, 40);
+ SHA1_Update(&sha, key, This->secure.rc4_key_len);
+ SHA1_Final(shasig, &sha);
+
+ MD5_Init(&md5);
+ MD5_Update(&md5, update_key, This->secure.rc4_key_len);
+ MD5_Update(&md5, pad_92, 48);
+ MD5_Update(&md5, shasig, 20);
+ MD5_Final(key, &md5);
+
+ RC4_set_key(&update, This->secure.rc4_key_len, key);
+ RC4(&update, This->secure.rc4_key_len, key, key);
+
+ if (This->secure.rc4_key_len == 8)
+ sec_make_40bit(key);
+}
+
+/* Encrypt data using RC4 */
+static void
+sec_encrypt(RDPCLIENT * This, uint8 * data, int length)
+{
+ if (This->secure.encrypt_use_count == 4096)
+ {
+ sec_update(This, This->secure.encrypt_key, This->secure.encrypt_update_key);
+ RC4_set_key(&This->secure.rc4_encrypt_key, This->secure.rc4_key_len, This->secure.encrypt_key);
+ This->secure.encrypt_use_count = 0;
+ }
+
+ RC4(&This->secure.rc4_encrypt_key, length, data, data);
+ This->secure.encrypt_use_count++;
+}
+
+/* Decrypt data using RC4 */
+void
+sec_decrypt(RDPCLIENT * This, uint8 * data, int length)
+{
+ if (This->secure.decrypt_use_count == 4096)
+ {
+ sec_update(This, This->secure.decrypt_key, This->secure.decrypt_update_key);
+ RC4_set_key(&This->secure.rc4_decrypt_key, This->secure.rc4_key_len, This->secure.decrypt_key);
+ This->secure.decrypt_use_count = 0;
+ }
+
+ RC4(&This->secure.rc4_decrypt_key, length, data, data);
+ This->secure.decrypt_use_count++;
+}
+
+static void
+reverse(uint8 * p, int len)
+{
+ int i, j;
+ uint8 temp;
+
+ for (i = 0, j = len - 1; i < j; i++, j--)
+ {
+ temp = p[i];
+ p[i] = p[j];
+ p[j] = temp;
+ }
+}
+
+/* Perform an RSA public key encryption operation */
+static void
+sec_rsa_encrypt(uint8 * out, uint8 * in, int len, uint32 modulus_size, uint8 * modulus,
+ uint8 * exponent)
+{
+ BN_CTX *ctx;
+ BIGNUM mod, exp, x, y;
+ uint8 inr[SEC_MAX_MODULUS_SIZE];
+ int outlen;
+
+ reverse(modulus, modulus_size);
+ reverse(exponent, SEC_EXPONENT_SIZE);
+ memcpy(inr, in, len);
+ reverse(inr, len);
+
+ ctx = BN_CTX_new();
+ BN_init(&mod);
+ BN_init(&exp);
+ BN_init(&x);
+ BN_init(&y);
+
+ BN_bin2bn(modulus, modulus_size, &mod);
+ BN_bin2bn(exponent, SEC_EXPONENT_SIZE, &exp);
+ BN_bin2bn(inr, len, &x);
+ BN_mod_exp(&y, &x, &exp, &mod, ctx);
+ outlen = BN_bn2bin(&y, out);
+ reverse(out, outlen);
+ if ((uint32)outlen < modulus_size)
+ memset(out + outlen, 0, modulus_size - outlen);
+
+ BN_free(&y);
+ BN_clear_free(&x);
+ BN_free(&exp);
+ BN_free(&mod);
+ BN_CTX_free(ctx);
+}
+
+/* Initialise secure transport packet */
+STREAM
+sec_init(RDPCLIENT * This, uint32 flags, int maxlen)
+{
+ int hdrlen;
+ STREAM s;
+
+ if (!This->licence_issued)
+ hdrlen = (flags & SEC_ENCRYPT) ? 12 : 4;
+ else
+ hdrlen = (flags & SEC_ENCRYPT) ? 12 : 0;
+ s = mcs_init(This, maxlen + hdrlen);
+
+ if(s == NULL)
+ return s;
+
+ s_push_layer(s, sec_hdr, hdrlen);
+
+ return s;
+}
+
+/* Transmit secure transport packet over specified channel */
+
+// !!! we need a lock here !!!
+BOOL
+sec_send_to_channel(RDPCLIENT * This, STREAM s, uint32 flags, uint16 channel)
+{
+ int datalen;
+
+ s_pop_layer(s, sec_hdr);
+ if (!This->licence_issued || (flags & SEC_ENCRYPT))
+ out_uint32_le(s, flags);
+
+ if (flags & SEC_ENCRYPT)
+ {
+ flags &= ~SEC_ENCRYPT;
+ datalen = (int)(s->end - s->p - 8);
+
+#if WITH_DEBUG
+ DEBUG(("Sending encrypted packet:\n"));
+ hexdump(s->p + 8, datalen);
+#endif
+
+ sec_sign(s->p, 8, This->secure.sign_key, This->secure.rc4_key_len, s->p + 8, datalen);
+ sec_encrypt(This, s->p + 8, datalen);
+ }
+
+ return mcs_send_to_channel(This, s, channel);
+}
+
+/* Transmit secure transport packet */
+
+BOOL
+sec_send(RDPCLIENT * This, STREAM s, uint32 flags)
+{
+ return sec_send_to_channel(This, s, flags, MCS_GLOBAL_CHANNEL);
+}
+
+
+/* Transfer the client random to the server */
+static void
+sec_establish_key(RDPCLIENT * This)
+{
+ uint32 length = This->secure.server_public_key_len + SEC_PADDING_SIZE;
+ uint32 flags = SEC_CLIENT_RANDOM;
+ STREAM s;
+
+ s = sec_init(This, flags, length + 4);
+
+ out_uint32_le(s, length);
+ out_uint8p(s, This->secure.crypted_random, This->secure.server_public_key_len);
+ out_uint8s(s, SEC_PADDING_SIZE);
+
+ s_mark_end(s);
+ sec_send(This, s, flags);
+}
+
+/* Output connect initial data blob */
+static void
+sec_out_mcs_data(RDPCLIENT * This, STREAM s, wchar_t * hostname)
+{
+ int hostlen = 2 * (int)wcslen(hostname);
+ int length = 158 + 76 + 12 + 4;
+ unsigned int i;
+
+ if (This->num_channels > 0)
+ length += This->num_channels * 12 + 8;
+
+ if (hostlen > 30)
+ hostlen = 30;
+
+ /* Generic Conference Control (T.124) ConferenceCreateRequest */
+ out_uint16_be(s, 5);
+ out_uint16_be(s, 0x14);
+ out_uint8(s, 0x7c);
+ out_uint16_be(s, 1);
+
+ out_uint16_be(s, (length | 0x8000)); /* remaining length */
+
+ out_uint16_be(s, 8); /* length? */
+ out_uint16_be(s, 16);
+ out_uint8(s, 0);
+ out_uint16_le(s, 0xc001);
+ out_uint8(s, 0);
+
+ out_uint32_le(s, 0x61637544); /* OEM ID: "Duca", as in Ducati. */
+ out_uint16_be(s, ((length - 14) | 0x8000)); /* remaining length */
+
+ /* Client information */
+ out_uint16_le(s, SEC_TAG_CLI_INFO);
+ out_uint16_le(s, 212); /* length */
+ out_uint16_le(s, This->use_rdp5 ? 4 : 1); /* RDP version. 1 == RDP4, 4 == RDP5. */
+ out_uint16_le(s, 8);
+ out_uint16_le(s, This->width);
+ out_uint16_le(s, This->height);
+ out_uint16_le(s, 0xca01);
+ out_uint16_le(s, 0xaa03);
+ out_uint32_le(s, This->keylayout);
+ out_uint32_le(s, 2600); /* Client build. We are now 2600 compatible :-) */
+
+ /* Unicode name of client, padded to 32 bytes */
+ rdp_out_unistr(This, s, hostname, hostlen);
+ out_uint8s(s, 30 - hostlen);
+
+ /* See
+ http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceddk40/html/cxtsksupportingremotedesktopprotocol.asp */
+ out_uint32_le(s, This->keyboard_type);
+ out_uint32_le(s, This->keyboard_subtype);
+ out_uint32_le(s, This->keyboard_functionkeys);
+ out_uint8s(s, 64); /* reserved? 4 + 12 doublewords */
+ out_uint16_le(s, 0xca01); /* colour depth? */
+ out_uint16_le(s, 1);
+
+ out_uint32(s, 0);
+ out_uint8(s, This->server_depth);
+ out_uint16_le(s, 0x0700);
+ out_uint8(s, 0);
+ out_uint32_le(s, 1);
+ out_uint8s(s, 64); /* End of client info */
+
+ out_uint16_le(s, SEC_TAG_CLI_4);
+ out_uint16_le(s, 12);
+ out_uint32_le(s, This->console_session ? 0xb : 9);
+ out_uint32(s, 0);
+
+ /* Client encryption settings */
+ out_uint16_le(s, SEC_TAG_CLI_CRYPT);
+ out_uint16_le(s, 12); /* length */
+ out_uint32_le(s, This->encryption ? 0x3 : 0); /* encryption supported, 128-bit supported */
+ out_uint32(s, 0); /* Unknown */
+
+ DEBUG_RDP5(("This->num_channels is %d\n", This->num_channels));
+ if (This->num_channels > 0)
+ {
+ out_uint16_le(s, SEC_TAG_CLI_CHANNELS);
+ out_uint16_le(s, This->num_channels * 12 + 8); /* length */
+ out_uint32_le(s, This->num_channels); /* number of virtual channels */
+ for (i = 0; i < This->num_channels; i++)
+ {
+ DEBUG_RDP5(("Requesting channel %s\n", This->channels[i].name));
+ out_uint8a(s, This->channel_defs[i].name, 8);
+ out_uint32_be(s, This->channel_defs[i].options);
+ }
+ }
+
+ s_mark_end(s);
+}
+
+/* Parse a public key structure */
+static BOOL
+sec_parse_public_key(RDPCLIENT * This, STREAM s, uint8 ** modulus, uint8 ** exponent)
+{
+ uint32 magic, modulus_len;
+
+ in_uint32_le(s, magic);
+ if (magic != SEC_RSA_MAGIC)
+ {
+ error("RSA magic 0x%x\n", magic);
+ return False;
+ }
+
+ in_uint32_le(s, modulus_len);
+ modulus_len -= SEC_PADDING_SIZE;
+ if ((modulus_len < 64) || (modulus_len > SEC_MAX_MODULUS_SIZE))
+ {
+ error("Bad server public key size (%u bits)\n", modulus_len * 8);
+ return False;
+ }
+
+ in_uint8s(s, 8); /* modulus_bits, unknown */
+ in_uint8p(s, *exponent, SEC_EXPONENT_SIZE);
+ in_uint8p(s, *modulus, modulus_len);
+ in_uint8s(s, SEC_PADDING_SIZE);
+ This->secure.server_public_key_len = modulus_len;
+
+ return s_check(s);
+}
+
+static BOOL
+sec_parse_x509_key(RDPCLIENT * This, X509 * cert)
+{
+ EVP_PKEY *epk = NULL;
+ /* By some reason, Microsoft sets the OID of the Public RSA key to
+ the oid for "MD5 with RSA Encryption" instead of "RSA Encryption"
+
+ Kudos to Richard Levitte for the following (. intiutive .)
+ lines of code that resets the OID and let's us extract the key. */
+ if (OBJ_obj2nid(cert->cert_info->key->algor->algorithm) == NID_md5WithRSAEncryption)
+ {
+ DEBUG_RDP5(("Re-setting algorithm type to RSA in server certificate\n"));
+ ASN1_OBJECT_free(cert->cert_info->key->algor->algorithm);
+ cert->cert_info->key->algor->algorithm = OBJ_nid2obj(NID_rsaEncryption);
+ }
+ epk = X509_get_pubkey(cert);
+ if (NULL == epk)
+ {
+ error("Failed to extract public key from certificate\n");
+ return False;
+ }
+
+ This->secure.server_public_key = RSAPublicKey_dup((RSA *) epk->pkey.ptr);
+ EVP_PKEY_free(epk);
+
+ This->secure.server_public_key_len = RSA_size(This->secure.server_public_key);
+ if ((This->secure.server_public_key_len < 64) || (This->secure.server_public_key_len > SEC_MAX_MODULUS_SIZE))
+ {
+ error("Bad server public key size (%u bits)\n", This->secure.server_public_key_len * 8);
+ return False;
+ }
+
+ return True;
+}
+
+
+/* Parse a crypto information structure */
+static BOOL
+sec_parse_crypt_info(RDPCLIENT * This, STREAM s, uint32 * rc4_key_size,
+ uint8 ** server_random, uint8 ** modulus, uint8 ** exponent)
+{
+ uint32 crypt_level, random_len, rsa_info_len;
+ uint32 cacert_len, cert_len, flags;
+ X509 *cacert, *server_cert;
+ uint16 tag, length;
+ uint8 *next_tag, *end;
+
+ in_uint32_le(s, *rc4_key_size); /* 1 = 40-bit, 2 = 128-bit */
+ in_uint32_le(s, crypt_level); /* 1 = low, 2 = medium, 3 = high */
+ if (crypt_level == 0) /* no encryption */
+ return False;
+ in_uint32_le(s, random_len);
+ in_uint32_le(s, rsa_info_len);
+
+ if (random_len != SEC_RANDOM_SIZE)
+ {
+ error("random len %d, expected %d\n", random_len, SEC_RANDOM_SIZE);
+ return False;
+ }
+
+ in_uint8p(s, *server_random, random_len);
+
+ /* RSA info */
+ end = s->p + rsa_info_len;
+ if (end > s->end)
+ return False;
+
+ in_uint32_le(s, flags); /* 1 = RDP4-style, 0x80000002 = X.509 */
+ if (flags & 1)
+ {
+ DEBUG_RDP5(("We're going for the RDP4-style encryption\n"));
+ in_uint8s(s, 8); /* unknown */
+
+ while (s->p < end)
+ {
+ in_uint16_le(s, tag);
+ in_uint16_le(s, length);
+
+ next_tag = s->p + length;
+
+ switch (tag)
+ {
+ case SEC_TAG_PUBKEY:
+ if (!sec_parse_public_key(This, s, modulus, exponent))
+ return False;
+ DEBUG_RDP5(("Got Public key, RDP4-style\n"));
+
+ break;
+
+ case SEC_TAG_KEYSIG:
+ /* Is this a Microsoft key that we just got? */
+ /* Care factor: zero! */
+ /* Actually, it would probably be a good idea to check if the public key is signed with this key, and then store this
+ key as a known key of the hostname. This would prevent some MITM-attacks. */
+ break;
+
+ default:
+ unimpl("crypt tag 0x%x\n", tag);
+ }
+
+ s->p = next_tag;
+ }
+ }
+ else
+ {
+ uint32 certcount;
+
+ DEBUG_RDP5(("We're going for the RDP5-style encryption\n"));
+ in_uint32_le(s, certcount); /* Number of certificates */
+
+ if (certcount < 2)
+ {
+ error("Server didn't send enough X509 certificates\n");
+ This->disconnect_reason = 1798;
+ return False;
+ }
+
+ for (; certcount > 2; certcount--)
+ { /* ignore all the certificates between the root and the signing CA */
+ uint32 ignorelen;
+ X509 *ignorecert;
+
+ DEBUG_RDP5(("Ignored certs left: %d\n", certcount));
+
+ in_uint32_le(s, ignorelen);
+ DEBUG_RDP5(("Ignored Certificate length is %d\n", ignorelen));
+ ignorecert = d2i_X509(NULL, &(s->p), ignorelen);
+
+ if (ignorecert == NULL)
+ { /* XXX: error out? */
+ DEBUG_RDP5(("got a bad cert: this will probably screw up the rest of the communication\n"));
+ }
+
+#ifdef WITH_DEBUG_RDP5
+ DEBUG_RDP5(("cert #%d (ignored):\n", certcount));
+ X509_print_fp(stdout, ignorecert);
+#endif
+ }
+
+ /* Do da funky X.509 stuffy
+
+ "How did I find out about this? I looked up and saw a
+ bright light and when I came to I had a scar on my forehead
+ and knew about X.500"
+ - Peter Gutman in a early version of
+ http://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt
+ */
+
+ in_uint32_le(s, cacert_len);
+ DEBUG_RDP5(("CA Certificate length is %d\n", cacert_len));
+ cacert = d2i_X509(NULL, &(s->p), cacert_len);
+ /* Note: We don't need to move s->p here - d2i_X509 is
+ "kind" enough to do it for us */
+ if (NULL == cacert)
+ {
+ error("Couldn't load CA Certificate from server\n");
+ This->disconnect_reason = 1798;
+ return False;
+ }
+
+ /* Currently, we don't use the CA Certificate.
+ FIXME:
+ *) Verify the server certificate (server_cert) with the
+ CA certificate.
+ *) Store the CA Certificate with the hostname of the
+ server we are connecting to as key, and compare it
+ when we connect the next time, in order to prevent
+ MITM-attacks.
+ */
+
+ X509_free(cacert);
+
+ in_uint32_le(s, cert_len);
+ DEBUG_RDP5(("Certificate length is %d\n", cert_len));
+ server_cert = d2i_X509(NULL, &(s->p), cert_len);
+ if (NULL == server_cert)
+ {
+ error("Couldn't load Certificate from server\n");
+ This->disconnect_reason = 1798;
+ return False;
+ }
+
+ in_uint8s(s, 16); /* Padding */
+
+ /* Note: Verifying the server certificate must be done here,
+ before sec_parse_public_key since we'll have to apply
+ serious violence to the key after this */
+
+ if (!sec_parse_x509_key(This, server_cert))
+ {
+ DEBUG_RDP5(("Didn't parse X509 correctly\n"));
+ X509_free(server_cert);
+ This->disconnect_reason = 1798;
+ return False;
+ }
+ X509_free(server_cert);
+ return True; /* There's some garbage here we don't care about */
+ }
+ return s_check_end(s);
+}
+
+/* Process crypto information blob */
+static void
+sec_process_crypt_info(RDPCLIENT * This, STREAM s)
+{
+ uint8 *server_random, *modulus, *exponent;
+ uint8 client_random[SEC_RANDOM_SIZE];
+ uint32 rc4_key_size;
+
+ if (!sec_parse_crypt_info(This, s, &rc4_key_size, &server_random, &modulus, &exponent))
+ {
+ DEBUG(("Failed to parse crypt info\n"));
+ return;
+ }
+
+ DEBUG(("Generating client random\n"));
+ generate_random(client_random);
+
+ if (NULL != This->secure.server_public_key)
+ { /* Which means we should use
+ RDP5-style encryption */
+ uint8 inr[SEC_MAX_MODULUS_SIZE];
+ uint32 padding_len = This->secure.server_public_key_len - SEC_RANDOM_SIZE;
+
+ /* This is what the MS client do: */
+ memset(inr, 0, padding_len);
+ /* *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!
+ */
+ memcpy(inr + padding_len, client_random, SEC_RANDOM_SIZE);
+ reverse(inr + padding_len, SEC_RANDOM_SIZE);
+
+ RSA_public_encrypt(This->secure.server_public_key_len,
+ inr, This->secure.crypted_random, This->secure.server_public_key, RSA_NO_PADDING);
+
+ reverse(This->secure.crypted_random, This->secure.server_public_key_len);
+
+ RSA_free(This->secure.server_public_key);
+ This->secure.server_public_key = NULL;
+ }
+ else
+ { /* RDP4-style encryption */
+ sec_rsa_encrypt(This->secure.crypted_random,
+ client_random, SEC_RANDOM_SIZE, This->secure.server_public_key_len, modulus,
+ exponent);
+ }
+ sec_generate_keys(This, client_random, server_random, rc4_key_size);
+}
+
+
+/* Process SRV_INFO, find RDP version supported by server */
+static void
+sec_process_srv_info(RDPCLIENT * This, STREAM s)
+{
+ in_uint16_le(s, This->server_rdp_version);
+ DEBUG_RDP5(("Server RDP version is %d\n", This->server_rdp_version));
+ if (1 == This->server_rdp_version)
+ {
+ This->use_rdp5 = 0;
+ This->server_depth = 8;
+ }
+}
+
+
+/* Process connect response data blob */
+void
+sec_process_mcs_data(RDPCLIENT * This, STREAM s)
+{
+ uint16 tag, length;
+ uint8 *next_tag;
+ uint8 len;
+
+ in_uint8s(s, 21); /* header (T.124 ConferenceCreateResponse) */
+ in_uint8(s, len);
+ if (len & 0x80)
+ in_uint8(s, len);
+
+ while (s->p < s->end)
+ {
+ in_uint16_le(s, tag);
+ in_uint16_le(s, length);
+
+ if (length <= 4)
+ return;
+
+ next_tag = s->p + length - 4;
+
+ switch (tag)
+ {
+ case SEC_TAG_SRV_INFO:
+ sec_process_srv_info(This, s);
+ break;
+
+ case SEC_TAG_SRV_CRYPT:
+ sec_process_crypt_info(This, s);
+ break;
+
+ case SEC_TAG_SRV_CHANNELS:
+ /* FIXME: We should parse this information and
+ use it to map RDP5 channels to MCS
+ channels */
+ break;
+
+ default:
+ unimpl("response tag 0x%x\n", tag);
+ }
+
+ s->p = next_tag;
+ }
+}
+
+/* Receive secure transport packet */
+STREAM
+sec_recv(RDPCLIENT * This, uint8 * rdpver)
+{
+ uint32 sec_flags;
+ uint16 channel;
+ STREAM s;
+
+ while ((s = mcs_recv(This, &channel, rdpver)) != NULL)
+ {
+ if (rdpver != NULL)
+ {
+ if (*rdpver != 3)
+ {
+ if (*rdpver & 0x80)
+ {
+ in_uint8s(s, 8); /* signature */
+ sec_decrypt(This, s->p, (int)(s->end - s->p));
+ }
+ return s;
+ }
+ }
+ if (This->encryption || !This->licence_issued)
+ {
+ in_uint32_le(s, sec_flags);
+
+ if (sec_flags & SEC_ENCRYPT)
+ {
+ in_uint8s(s, 8); /* signature */
+ sec_decrypt(This, s->p, (int)(s->end - s->p));
+ }
+
+ if (sec_flags & SEC_LICENCE_NEG)
+ {
+ licence_process(This, s);
+ continue;
+ }
+
+ if (sec_flags & 0x0400) /* SEC_REDIRECT_ENCRYPT */
+ {
+ uint8 swapbyte;
+
+ in_uint8s(s, 8); /* signature */
+ sec_decrypt(This, s->p, (int)(s->end - s->p));
+
+ /* Check for a redirect packet, starts with 00 04 */
+ if (s->p[0] == 0 && s->p[1] == 4)
+ {
+ /* for some reason the PDU and the length seem to be swapped.
+ This isn't good, but we're going to do a byte for byte
+ swap. So the first foure value appear as: 00 04 XX YY,
+ where XX YY is the little endian length. We're going to
+ use 04 00 as the PDU type, so after our swap this will look
+ like: XX YY 04 00 */
+ swapbyte = s->p[0];
+ s->p[0] = s->p[2];
+ s->p[2] = swapbyte;
+
+ swapbyte = s->p[1];
+ s->p[1] = s->p[3];
+ s->p[3] = swapbyte;
+
+ swapbyte = s->p[2];
+ s->p[2] = s->p[3];
+ s->p[3] = swapbyte;
+ }
+#ifdef WITH_DEBUG
+ /* warning! this debug statement will show passwords in the clear! */
+ hexdump(s->p, s->end - s->p);
+#endif
+ }
+
+ }
+
+ if (channel != MCS_GLOBAL_CHANNEL)
+ {
+ channel_process(This, s, channel);
+ *rdpver = 0xff;
+ return s;
+ }
+
+ return s;
+ }
+
+ return NULL;
+}
+
+/* Establish a secure connection */
+BOOL
+sec_connect(RDPCLIENT * This, char *server, wchar_t *hostname, char *cookie)
+{
+ struct stream mcs_data;
+ void * p = malloc(512);
+
+ if(p == NULL)
+ {
+ This->disconnect_reason = 262;
+ return False;
+ }
+
+ /* We exchange some RDP data during the MCS-Connect */
+ mcs_data.size = 512;
+ mcs_data.p = mcs_data.data = (uint8 *) p;
+ sec_out_mcs_data(This, &mcs_data, hostname);
+
+ if (!mcs_connect(This, server, cookie, &mcs_data))
+ return False;
+
+ /* sec_process_mcs_data(&mcs_data); */
+ if (This->encryption)
+ sec_establish_key(This);
+ free(mcs_data.data);
+ return True;
+}
+
+/* Establish a secure connection */
+BOOL
+sec_reconnect(RDPCLIENT * This, char *server, wchar_t *hostname, char *cookie)
+{
+ struct stream mcs_data;
+ void * p = malloc(512);
+
+ if(p == NULL)
+ {
+ This->disconnect_reason = 262;
+ return False;
+ }
+
+ /* We exchange some RDP data during the MCS-Connect */
+ mcs_data.size = 512;
+ mcs_data.p = mcs_data.data = (uint8 *) p;
+ sec_out_mcs_data(This, &mcs_data, hostname);
+
+ if (!mcs_reconnect(This, server, cookie, &mcs_data))
+ return False;
+
+ /* sec_process_mcs_data(&mcs_data); */
+ if (This->encryption)
+ sec_establish_key(This);
+ free(mcs_data.data);
+ return True;
+}
+
+/* Disconnect a connection */
+void
+sec_disconnect(RDPCLIENT * This)
+{
+ mcs_disconnect(This);
+}
+
+/* reset the state of the sec layer */
+void
+sec_reset_state(RDPCLIENT * This)
+{
+ This->server_rdp_version = 0;
+ This->secure.encrypt_use_count = 0;
+ This->secure.decrypt_use_count = 0;
+ mcs_reset_state(This);
+}
projects / reactos.git / blobdiff