trunk/rdesktop/licence.c

/*
   rdesktop: A Remote Desktop Protocol client.
   RDP licensing negotiation
   Copyright (C) Matthew Chapman 1999-2002
   
   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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include "rdesktop.h"

#ifdef WITH_OPENSSL
#include <openssl/rc4.h>
#else
#include "crypto/rc4.h"
#endif

extern char username[16];
extern char hostname[16];

static uint8 licence_key[16];
static uint8 licence_sign_key[16];

BOOL licence_issued = False;


int
load_licence(unsigned char **data)
{
        char *path;
        char *home;
        struct stat st;
        int fd;

        home = getenv("HOME");
        if (home == NULL)
                return -1;

        path = xmalloc(strlen(home) + strlen(hostname) + 20);
        sprintf(path, "%s/.rdesktop/licence.%s", home, hostname);

        fd = open(path, O_RDONLY);
        if (fd == -1)
                return -1;

        if (fstat(fd, &st))
                return -1;

        *data = xmalloc(st.st_size);
        return read(fd, *data, st.st_size);
}

void
save_licence(unsigned char *data, int length)
{
        char *fpath;            /* file path for licence */
        char *fname, *fnamewrk; /* file name for licence .inkl path. */
        char *home;
        uint32 y;
        struct flock fnfl;
        int fnfd, fnwrkfd, i, wlen;
        struct stream s, *s_ptr;
        uint32 len;

        /* Construct a stream, so that we can use macros to extract the
         * licence.
         */
        s_ptr = &s;
        s_ptr->p = data;
        /* Skip first two bytes */
        in_uint16(s_ptr, len);

        /* Skip three strings */
        for (i = 0; i < 3; i++)
        {
                in_uint32(s_ptr, len);
                s_ptr->p += len;
                /* Make sure that we won't be past the end of data after
                 * reading the next length value
                 */
                if ((s_ptr->p) + 4 > data + length)
                {
                        printf("Error in parsing licence key.\n");
                        printf("Strings %d end value %x > supplied length (%x)\n", i, 
                               (unsigned int)s_ptr->p, 
                               (unsigned int)data + length);
                        return;
                }
        }
        in_uint32(s_ptr, len);
        if (s_ptr->p + len > data + length)
        {
                printf("Error in parsing licence key.\n");
                printf("End of licence %x > supplied length (%x)\n", 
                       (unsigned int)s_ptr->p + len, 
                       (unsigned int)data + length);
                return;
        }

        home = getenv("HOME");
        if (home == NULL)
                return;

        /* set and create the directory -- if it doesn't exist. */
        fpath = xmalloc(strlen(home) + 11);
        STRNCPY(fpath, home, strlen(home) + 1);

        sprintf(fpath, "%s/.rdesktop", fpath);
        if (mkdir(fpath, 0700) == -1 && errno != EEXIST)
        {
                perror("mkdir");
                exit(1);
        }

        /* set the real licence filename, and put a write lock on it. */
        fname = xmalloc(strlen(fpath) + strlen(hostname) + 10);
        sprintf(fname, "%s/licence.%s", fpath, hostname);
        fnfd = open(fname, O_RDONLY);
        if (fnfd != -1)
        {
                fnfl.l_type = F_WRLCK;
                fnfl.l_whence = SEEK_SET;
                fnfl.l_start = 0;
                fnfl.l_len = 1;
                fcntl(fnfd, F_SETLK, &fnfl);
        }

        /* create a temporary licence file */
        fnamewrk = xmalloc(strlen(fname) + 12);
        for (y = 0;; y++)
        {
                sprintf(fnamewrk, "%s.%lu", fname, (long unsigned int)y); 
                fnwrkfd = open(fnamewrk, O_WRONLY | O_CREAT | O_EXCL, 0600);
                if (fnwrkfd == -1)
                {
                        if (errno == EINTR || errno == EEXIST)
                                continue;
                        perror("create");
                        exit(1);
                }
                break;
        }
        /* write to the licence file */
        for (y = 0; y < len;)
        {
                do
                {
                        wlen = write(fnwrkfd, s_ptr->p + y, len - y);
                }
                while (wlen == -1 && errno == EINTR);
                if (wlen < 1)
                {
                        perror("write");
                        unlink(fnamewrk);
                        exit(1);
                }
                y += wlen;
        }

        /* close the file and rename it to fname */
        if (close(fnwrkfd) == -1)
        {
                perror("close");
                unlink(fnamewrk);
                exit(1);
        }
        if (rename(fnamewrk, fname) == -1)
        {
                perror("rename");
                unlink(fnamewrk);
                exit(1);
        }
        /* close the file lock on fname */
        if (fnfd != -1)
        {
                fnfl.l_type = F_UNLCK;
                fnfl.l_whence = SEEK_SET;
                fnfl.l_start = 0;
                fnfl.l_len = 1;
                fcntl(fnfd, F_SETLK, &fnfl);
                close(fnfd);
        }

}

/* Generate a session key and RC4 keys, given client and server randoms */
static void
licence_generate_keys(uint8 * client_key, uint8 * server_key, uint8 * client_rsa)
{
        uint8 session_key[48];
        uint8 temp_hash[48];

        /* Generate session key - two rounds of sec_hash_48 */
        sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
        sec_hash_48(session_key, temp_hash, server_key, client_key, 65);

        /* Store first 16 bytes of session key, for generating signatures */
        memcpy(licence_sign_key, session_key, 16);

        /* Generate RC4 key */
        sec_hash_16(licence_key, &session_key[16], client_key, server_key);
}

static void
licence_generate_hwid(uint8 * hwid)
{
        buf_out_uint32(hwid, 2);
        strncpy((char *) (hwid + 4), hostname, LICENCE_HWID_SIZE - 4);
}

/* Present an existing licence to the server */
static void
licence_present(uint8 * client_random, uint8 * rsa_data,
                uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 length =
                16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
                licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
        STREAM s;

        s = sec_init(sec_flags, length + 4);

        out_uint16_le(s, LICENCE_TAG_PRESENT);
        out_uint16_le(s, length);

        out_uint32_le(s, 1);
        out_uint16(s, 0);
        out_uint16_le(s, 0x0201);

        out_uint8p(s, client_random, SEC_RANDOM_SIZE);
        out_uint16(s, 0);
        out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
        out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
        out_uint8s(s, SEC_PADDING_SIZE);

        out_uint16_le(s, 1);
        out_uint16_le(s, licence_size);
        out_uint8p(s, licence_data, licence_size);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_HWID_SIZE);
        out_uint8p(s, hwid, LICENCE_HWID_SIZE);

        out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Send a licence request packet */
static void
licence_send_request(uint8 * client_random, uint8 * rsa_data, char *user, char *host)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 userlen = strlen(user) + 1;
        uint16 hostlen = strlen(host) + 1;
        uint16 length = 128 + userlen + hostlen;
        STREAM s;

        s = sec_init(sec_flags, length + 2);

        out_uint16_le(s, LICENCE_TAG_REQUEST);
        out_uint16_le(s, length);

        out_uint32_le(s, 1);
        out_uint16(s, 0);
        out_uint16_le(s, 0xff01);

        out_uint8p(s, client_random, SEC_RANDOM_SIZE);
        out_uint16(s, 0);
        out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
        out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
        out_uint8s(s, SEC_PADDING_SIZE);

        out_uint16(s, LICENCE_TAG_USER);
        out_uint16(s, userlen);
        out_uint8p(s, user, userlen);

        out_uint16(s, LICENCE_TAG_HOST);
        out_uint16(s, hostlen);
        out_uint8p(s, host, hostlen);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Process a licence demand packet */
static void
licence_process_demand(STREAM s)
{
        uint8 null_data[SEC_MODULUS_SIZE];
        uint8 *server_random;
        uint8 signature[LICENCE_SIGNATURE_SIZE];
        uint8 hwid[LICENCE_HWID_SIZE];
        uint8 *licence_data;
        int licence_size;
        RC4_KEY crypt_key;

        /* Retrieve the server random from the incoming packet */
        in_uint8p(s, server_random, SEC_RANDOM_SIZE);

        /* We currently use null client keys. This is a bit naughty but, hey,
           the security of licence negotiation isn't exactly paramount. */
        memset(null_data, 0, sizeof(null_data));
        licence_generate_keys(null_data, server_random, null_data);

        licence_size = load_licence(&licence_data);
        if (licence_size != -1)
        {
                /* Generate a signature for the HWID buffer */
                licence_generate_hwid(hwid);
                sec_sign(signature, 16, licence_sign_key, 16, hwid, sizeof(hwid));

                /* Now encrypt the HWID */
                RC4_set_key(&crypt_key, 16, licence_key);
                RC4(&crypt_key, sizeof(hwid), hwid, hwid);

                licence_present(null_data, null_data, licence_data, licence_size, hwid, signature);
                xfree(licence_data);
                return;
        }

        licence_send_request(null_data, null_data, username, hostname);
}

/* Send an authentication response packet */
static void
licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
{
        uint32 sec_flags = SEC_LICENCE_NEG;
        uint16 length = 58;
        STREAM s;

        s = sec_init(sec_flags, length + 2);

        out_uint16_le(s, LICENCE_TAG_AUTHRESP);
        out_uint16_le(s, length);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_TOKEN_SIZE);
        out_uint8p(s, token, LICENCE_TOKEN_SIZE);

        out_uint16_le(s, 1);
        out_uint16_le(s, LICENCE_HWID_SIZE);
        out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);

        out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);

        s_mark_end(s);
        sec_send(s, sec_flags);
}

/* Parse an authentication request packet */
static BOOL
licence_parse_authreq(STREAM s, uint8 ** token, uint8 ** signature)
{
        uint16 tokenlen;

        in_uint8s(s, 6);        /* unknown: f8 3d 15 00 04 f6 */

        in_uint16_le(s, tokenlen);
        if (tokenlen != LICENCE_TOKEN_SIZE)
        {
                error("token len %d\n", tokenlen);
                return False;
        }

        in_uint8p(s, *token, tokenlen);
        in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);

        return s_check_end(s);
}

/* Process an authentication request packet */
static void
licence_process_authreq(STREAM s)
{
        uint8 *in_token, *in_sig;
        uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
        uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
        uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
        uint8 out_sig[LICENCE_SIGNATURE_SIZE];
        RC4_KEY crypt_key;

        /* Parse incoming packet and save the encrypted token */
        licence_parse_authreq(s, &in_token, &in_sig);
        memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);

        /* Decrypt the token. It should read TEST in Unicode. */
        RC4_set_key(&crypt_key, 16, licence_key);
        RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);

        /* Generate a signature for a buffer of token and HWID */
        licence_generate_hwid(hwid);
        memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
        memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
        sec_sign(out_sig, 16, licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));

        /* Now encrypt the HWID */
        RC4_set_key(&crypt_key, 16, licence_key);
        RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);

        licence_send_authresp(out_token, crypt_hwid, out_sig);
}

/* Process an licence issue packet */
static void
licence_process_issue(STREAM s)
{
        RC4_KEY crypt_key;
        uint32 length;
        uint16 check;

        in_uint8s(s, 2);        /* 3d 45 - unknown */
        in_uint16_le(s, length);
        if (!s_check_rem(s, length))
                return;

        RC4_set_key(&crypt_key, 16, licence_key);
        RC4(&crypt_key, length, s->p, s->p);

        in_uint16(s, check);
        if (check != 0)
                return;

        licence_issued = True;
        save_licence(s->p, length - 2);
}

/* Process a licence packet */
void
licence_process(STREAM s)
{
        uint16 tag;

        in_uint16_le(s, tag);
        in_uint8s(s, 2);        /* length */

        switch (tag)
        {
                case LICENCE_TAG_DEMAND:
                        licence_process_demand(s);
                        break;

                case LICENCE_TAG_AUTHREQ:
                        licence_process_authreq(s);
                        break;

                case LICENCE_TAG_ISSUE:
                        licence_process_issue(s);
                        break;

                case LICENCE_TAG_REISSUE:
                        break;

                case LICENCE_TAG_RESULT:
                        break;

                default:
                        unimpl("licence tag 0x%x\n", tag);
        }
}

1	matty	10	/*
2			rdesktop: A Remote Desktop Protocol client.
3			RDP licensing negotiation
4	matthewc	207	Copyright (C) Matthew Chapman 1999-2002
5	matty	10
6			This program is free software; you can redistribute it and/or modify
7			it under the terms of the GNU General Public License as published by
8			the Free Software Foundation; either version 2 of the License, or
9			(at your option) any later version.
10	jsorg71	60
11	matty	10	This program is distributed in the hope that it will be useful,
12			but WITHOUT ANY WARRANTY; without even the implied warranty of
13			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			GNU General Public License for more details.
15
16			You should have received a copy of the GNU General Public License
17			along with this program; if not, write to the Free Software
18			Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19			*/
20
21	astrand	317	#include <sys/types.h>
22			#include <sys/stat.h>
23			#include <unistd.h>
24			#include <fcntl.h>
25			#include <errno.h>
26	matty	10	#include "rdesktop.h"
27	astrand	293
28			#ifdef WITH_OPENSSL
29			#include <openssl/rc4.h>
30			#else
31	matty	10	#include "crypto/rc4.h"
32	astrand	293	#endif
33	matty	10
34			extern char username[16];
35			extern char hostname[16];
36
37			static uint8 licence_key[16];
38			static uint8 licence_sign_key[16];
39
40	matty	28	BOOL licence_issued = False;
41
42	astrand	317
43			int
44			load_licence(unsigned char **data)
45			{
46			char *path;
47			char *home;
48			struct stat st;
49			int fd;
50
51			home = getenv("HOME");
52			if (home == NULL)
53			return -1;
54
55			path = xmalloc(strlen(home) + strlen(hostname) + 20);
56			sprintf(path, "%s/.rdesktop/licence.%s", home, hostname);
57
58			fd = open(path, O_RDONLY);
59			if (fd == -1)
60			return -1;
61
62			if (fstat(fd, &st))
63			return -1;
64
65			*data = xmalloc(st.st_size);
66			return read(fd, *data, st.st_size);
67			}
68
69			void
70			save_licence(unsigned char *data, int length)
71			{
72			char fpath; / file path for licence */
73			char fname, fnamewrk; /* file name for licence .inkl path. */
74			char *home;
75			uint32 y;
76			struct flock fnfl;
77			int fnfd, fnwrkfd, i, wlen;
78			struct stream s, *s_ptr;
79			uint32 len;
80
81			/* Construct a stream, so that we can use macros to extract the
82			* licence.
83			*/
84			s_ptr = &s;
85			s_ptr->p = data;
86			/* Skip first two bytes */
87			in_uint16(s_ptr, len);
88
89			/* Skip three strings */
90			for (i = 0; i < 3; i++)
91			{
92			in_uint32(s_ptr, len);
93			s_ptr->p += len;
94			/* Make sure that we won't be past the end of data after
95			* reading the next length value
96			*/
97			if ((s_ptr->p) + 4 > data + length)
98			{
99			printf("Error in parsing licence key.\n");
100			printf("Strings %d end value %x > supplied length (%x)\n", i,
101			(unsigned int)s_ptr->p,
102			(unsigned int)data + length);
103			return;
104			}
105			}
106			in_uint32(s_ptr, len);
107			if (s_ptr->p + len > data + length)
108			{
109			printf("Error in parsing licence key.\n");
110			printf("End of licence %x > supplied length (%x)\n",
111			(unsigned int)s_ptr->p + len,
112			(unsigned int)data + length);
113			return;
114			}
115
116			home = getenv("HOME");
117			if (home == NULL)
118			return;
119
120			/* set and create the directory -- if it doesn't exist. */
121			fpath = xmalloc(strlen(home) + 11);
122			STRNCPY(fpath, home, strlen(home) + 1);
123
124			sprintf(fpath, "%s/.rdesktop", fpath);
125			if (mkdir(fpath, 0700) == -1 && errno != EEXIST)
126			{
127			perror("mkdir");
128			exit(1);
129			}
130
131			/* set the real licence filename, and put a write lock on it. */
132			fname = xmalloc(strlen(fpath) + strlen(hostname) + 10);
133			sprintf(fname, "%s/licence.%s", fpath, hostname);
134			fnfd = open(fname, O_RDONLY);
135			if (fnfd != -1)
136			{
137			fnfl.l_type = F_WRLCK;
138			fnfl.l_whence = SEEK_SET;
139			fnfl.l_start = 0;
140			fnfl.l_len = 1;
141			fcntl(fnfd, F_SETLK, &fnfl);
142			}
143
144			/* create a temporary licence file */
145			fnamewrk = xmalloc(strlen(fname) + 12);
146			for (y = 0;; y++)
147			{
148			sprintf(fnamewrk, "%s.%lu", fname, (long unsigned int)y);
149			fnwrkfd = open(fnamewrk, O_WRONLY \| O_CREAT \| O_EXCL, 0600);
150			if (fnwrkfd == -1)
151			{
152			if (errno == EINTR \|\| errno == EEXIST)
153			continue;
154			perror("create");
155			exit(1);
156			}
157			break;
158			}
159			/* write to the licence file */
160			for (y = 0; y < len;)
161			{
162			do
163			{
164			wlen = write(fnwrkfd, s_ptr->p + y, len - y);
165			}
166			while (wlen == -1 && errno == EINTR);
167			if (wlen < 1)
168			{
169			perror("write");
170			unlink(fnamewrk);
171			exit(1);
172			}
173			y += wlen;
174			}
175
176			/* close the file and rename it to fname */
177			if (close(fnwrkfd) == -1)
178			{
179			perror("close");
180			unlink(fnamewrk);
181			exit(1);
182			}
183			if (rename(fnamewrk, fname) == -1)
184			{
185			perror("rename");
186			unlink(fnamewrk);
187			exit(1);
188			}
189			/* close the file lock on fname */
190			if (fnfd != -1)
191			{
192			fnfl.l_type = F_UNLCK;
193			fnfl.l_whence = SEEK_SET;
194			fnfl.l_start = 0;
195			fnfl.l_len = 1;
196			fcntl(fnfd, F_SETLK, &fnfl);
197			close(fnfd);
198			}
199
200			}
201
202	matty	10	/* Generate a session key and RC4 keys, given client and server randoms */
203	matthewc	39	static void
204	astrand	82	licence_generate_keys(uint8 * client_key, uint8 * server_key, uint8 * client_rsa)
205	matty	10	{
206			uint8 session_key[48];
207			uint8 temp_hash[48];
208
209			/* Generate session key - two rounds of sec_hash_48 */
210	matty	24	sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65);
211			sec_hash_48(session_key, temp_hash, server_key, client_key, 65);
212	matty	10
213			/* Store first 16 bytes of session key, for generating signatures */
214	matty	24	memcpy(licence_sign_key, session_key, 16);
215	matty	10
216			/* Generate RC4 key */
217			sec_hash_16(licence_key, &session_key[16], client_key, server_key);
218			}
219
220	matthewc	39	static void
221	astrand	64	licence_generate_hwid(uint8 * hwid)
222	matthewc	39	{
223			buf_out_uint32(hwid, 2);
224	astrand	77	strncpy((char *) (hwid + 4), hostname, LICENCE_HWID_SIZE - 4);
225	matthewc	39	}
226
227			/* Present an existing licence to the server */
228			static void
229	astrand	64	licence_present(uint8 * client_random, uint8 * rsa_data,
230	astrand	82	uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature)
231	matthewc	39	{
232			uint32 sec_flags = SEC_LICENCE_NEG;
233	astrand	64	uint16 length =
234			16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE +
235			licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE;
236	matthewc	39	STREAM s;
237
238			s = sec_init(sec_flags, length + 4);
239
240			out_uint16_le(s, LICENCE_TAG_PRESENT);
241			out_uint16_le(s, length);
242
243			out_uint32_le(s, 1);
244			out_uint16(s, 0);
245			out_uint16_le(s, 0x0201);
246
247			out_uint8p(s, client_random, SEC_RANDOM_SIZE);
248			out_uint16(s, 0);
249			out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
250			out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
251			out_uint8s(s, SEC_PADDING_SIZE);
252
253			out_uint16_le(s, 1);
254			out_uint16_le(s, licence_size);
255			out_uint8p(s, licence_data, licence_size);
256
257			out_uint16_le(s, 1);
258			out_uint16_le(s, LICENCE_HWID_SIZE);
259			out_uint8p(s, hwid, LICENCE_HWID_SIZE);
260
261			out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
262
263			s_mark_end(s);
264			sec_send(s, sec_flags);
265			}
266
267	matty	10	/* Send a licence request packet */
268	matty	25	static void
269	astrand	82	licence_send_request(uint8 * client_random, uint8 * rsa_data, char user, char host)
270	matty	10	{
271			uint32 sec_flags = SEC_LICENCE_NEG;
272			uint16 userlen = strlen(user) + 1;
273			uint16 hostlen = strlen(host) + 1;
274	jsorg71	60	uint16 length = 128 + userlen + hostlen;
275	matty	10	STREAM s;
276
277			s = sec_init(sec_flags, length + 2);
278
279			out_uint16_le(s, LICENCE_TAG_REQUEST);
280			out_uint16_le(s, length);
281
282			out_uint32_le(s, 1);
283	matthewc	39	out_uint16(s, 0);
284			out_uint16_le(s, 0xff01);
285	matty	10
286			out_uint8p(s, client_random, SEC_RANDOM_SIZE);
287			out_uint16(s, 0);
288			out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE));
289			out_uint8p(s, rsa_data, SEC_MODULUS_SIZE);
290			out_uint8s(s, SEC_PADDING_SIZE);
291
292			out_uint16(s, LICENCE_TAG_USER);
293			out_uint16(s, userlen);
294			out_uint8p(s, user, userlen);
295
296			out_uint16(s, LICENCE_TAG_HOST);
297			out_uint16(s, hostlen);
298			out_uint8p(s, host, hostlen);
299
300			s_mark_end(s);
301			sec_send(s, sec_flags);
302			}
303
304			/* Process a licence demand packet */
305	matty	25	static void
306			licence_process_demand(STREAM s)
307	matty	10	{
308			uint8 null_data[SEC_MODULUS_SIZE];
309	matthewc	190	uint8 *server_random;
310			uint8 signature[LICENCE_SIGNATURE_SIZE];
311	matthewc	39	uint8 hwid[LICENCE_HWID_SIZE];
312			uint8 *licence_data;
313			int licence_size;
314			RC4_KEY crypt_key;
315	matty	10
316			/* Retrieve the server random from the incoming packet */
317			in_uint8p(s, server_random, SEC_RANDOM_SIZE);
318
319			/* We currently use null client keys. This is a bit naughty but, hey,
320			the security of licence negotiation isn't exactly paramount. */
321			memset(null_data, 0, sizeof(null_data));
322			licence_generate_keys(null_data, server_random, null_data);
323
324	matthewc	39	licence_size = load_licence(&licence_data);
325	matthewc	159	if (licence_size != -1)
326	matthewc	39	{
327	matthewc	159	/* Generate a signature for the HWID buffer */
328			licence_generate_hwid(hwid);
329			sec_sign(signature, 16, licence_sign_key, 16, hwid, sizeof(hwid));
330
331			/* Now encrypt the HWID */
332			RC4_set_key(&crypt_key, 16, licence_key);
333			RC4(&crypt_key, sizeof(hwid), hwid, hwid);
334
335			licence_present(null_data, null_data, licence_data, licence_size, hwid, signature);
336			xfree(licence_data);
337	matthewc	39	return;
338			}
339
340	matthewc	159	licence_send_request(null_data, null_data, username, hostname);
341	matty	10	}
342
343			/* Send an authentication response packet */
344	matty	25	static void
345	astrand	64	licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature)
346	matty	10	{
347			uint32 sec_flags = SEC_LICENCE_NEG;
348			uint16 length = 58;
349			STREAM s;
350
351			s = sec_init(sec_flags, length + 2);
352
353			out_uint16_le(s, LICENCE_TAG_AUTHRESP);
354			out_uint16_le(s, length);
355
356			out_uint16_le(s, 1);
357			out_uint16_le(s, LICENCE_TOKEN_SIZE);
358			out_uint8p(s, token, LICENCE_TOKEN_SIZE);
359
360			out_uint16_le(s, 1);
361			out_uint16_le(s, LICENCE_HWID_SIZE);
362			out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE);
363
364			out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE);
365
366			s_mark_end(s);
367			sec_send(s, sec_flags);
368			}
369
370			/* Parse an authentication request packet */
371	matty	25	static BOOL
372	astrand	64	licence_parse_authreq(STREAM s, uint8 token, uint8 signature)
373	matty	10	{
374			uint16 tokenlen;
375
376	matty	24	in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */
377	matty	10
378			in_uint16_le(s, tokenlen);
379			if (tokenlen != LICENCE_TOKEN_SIZE)
380			{
381	matty	30	error("token len %d\n", tokenlen);
382	matty	10	return False;
383			}
384
385			in_uint8p(s, *token, tokenlen);
386			in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE);
387
388			return s_check_end(s);
389			}
390
391			/* Process an authentication request packet */
392	matty	25	static void
393			licence_process_authreq(STREAM s)
394	matty	10	{
395			uint8 in_token, in_sig;
396	astrand	82	uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE];
397	matty	10	uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE];
398			uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE];
399			uint8 out_sig[LICENCE_SIGNATURE_SIZE];
400			RC4_KEY crypt_key;
401
402			/* Parse incoming packet and save the encrypted token */
403			licence_parse_authreq(s, &in_token, &in_sig);
404			memcpy(out_token, in_token, LICENCE_TOKEN_SIZE);
405
406			/* Decrypt the token. It should read TEST in Unicode. */
407			RC4_set_key(&crypt_key, 16, licence_key);
408			RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token);
409
410			/* Generate a signature for a buffer of token and HWID */
411	matthewc	39	licence_generate_hwid(hwid);
412	matty	10	memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE);
413			memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE);
414	astrand	82	sec_sign(out_sig, 16, licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer));
415	matty	10
416			/* Now encrypt the HWID */
417			RC4_set_key(&crypt_key, 16, licence_key);
418			RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid);
419
420			licence_send_authresp(out_token, crypt_hwid, out_sig);
421			}
422
423			/* Process an licence issue packet */
424	matty	25	static void
425			licence_process_issue(STREAM s)
426	matty	10	{
427			RC4_KEY crypt_key;
428			uint32 length;
429			uint16 check;
430
431	matty	24	in_uint8s(s, 2); /* 3d 45 - unknown */
432	matty	10	in_uint16_le(s, length);
433			if (!s_check_rem(s, length))
434			return;
435
436			RC4_set_key(&crypt_key, 16, licence_key);
437			RC4(&crypt_key, length, s->p, s->p);
438
439			in_uint16(s, check);
440			if (check != 0)
441			return;
442
443	matty	28	licence_issued = True;
444	astrand	64	save_licence(s->p, length - 2);
445	matty	10	}
446
447			/* Process a licence packet */
448	matty	25	void
449			licence_process(STREAM s)
450	matty	10	{
451			uint16 tag;
452
453			in_uint16_le(s, tag);
454	matty	24	in_uint8s(s, 2); /* length */
455	matty	10
456			switch (tag)
457			{
458			case LICENCE_TAG_DEMAND:
459			licence_process_demand(s);
460			break;
461
462			case LICENCE_TAG_AUTHREQ:
463			licence_process_authreq(s);
464			break;
465
466			case LICENCE_TAG_ISSUE:
467			licence_process_issue(s);
468			break;
469
470	matthewc	39	case LICENCE_TAG_REISSUE:
471			break;
472
473	matty	10	case LICENCE_TAG_RESULT:
474			break;
475
476			default:
477	matty	30	unimpl("licence tag 0x%x\n", tag);
478	matty	10	}
479			}
480	astrand	317