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/* |
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rdesktop: A Remote Desktop Protocol client. |
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RDP licensing negotiation |
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Copyright (C) Matthew Chapman 1999-2002 |
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|
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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*/ |
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|
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#include <sys/types.h> |
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#include <sys/stat.h> |
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#include <unistd.h> |
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#include <fcntl.h> |
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#include <errno.h> |
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#include "rdesktop.h" |
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|
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#ifdef WITH_OPENSSL |
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#include <openssl/rc4.h> |
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#else |
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#include "crypto/rc4.h" |
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#endif |
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|
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extern char username[16]; |
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extern char hostname[16]; |
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|
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static uint8 licence_key[16]; |
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static uint8 licence_sign_key[16]; |
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|
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BOOL licence_issued = False; |
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|
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|
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static int |
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load_licence(unsigned char **data) |
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{ |
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char *path; |
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char *home; |
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struct stat st; |
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int fd; |
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|
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home = getenv("HOME"); |
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if (home == NULL) |
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return -1; |
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|
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path = xmalloc(strlen(home) + strlen(hostname) + 20); |
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sprintf(path, "%s/.rdesktop/licence.%s", home, hostname); |
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|
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fd = open(path, O_RDONLY); |
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if (fd == -1) |
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return -1; |
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|
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if (fstat(fd, &st)) |
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return -1; |
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|
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*data = xmalloc(st.st_size); |
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return read(fd, *data, st.st_size); |
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} |
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|
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static void |
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save_licence(unsigned char *data, int length) |
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{ |
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char *fpath; /* file path for licence */ |
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char *fname, *fnamewrk; /* file name for licence .inkl path. */ |
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char *home; |
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uint32 y; |
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struct flock fnfl; |
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int fnfd, fnwrkfd, i, wlen; |
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struct stream s, *s_ptr; |
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uint32 len; |
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|
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/* Construct a stream, so that we can use macros to extract the |
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* licence. |
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*/ |
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s_ptr = &s; |
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s_ptr->p = data; |
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/* Skip first two bytes */ |
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in_uint16(s_ptr, len); |
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|
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/* Skip three strings */ |
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for (i = 0; i < 3; i++) |
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{ |
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in_uint32(s_ptr, len); |
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s_ptr->p += len; |
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/* Make sure that we won't be past the end of data after |
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* reading the next length value |
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*/ |
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if ((s_ptr->p) + 4 > data + length) |
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{ |
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printf("Error in parsing licence key.\n"); |
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printf("Strings %d end value %x > supplied length (%x)\n", i, |
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(unsigned int) s_ptr->p, (unsigned int) data + length); |
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return; |
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} |
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} |
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in_uint32(s_ptr, len); |
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if (s_ptr->p + len > data + length) |
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{ |
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printf("Error in parsing licence key.\n"); |
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printf("End of licence %x > supplied length (%x)\n", |
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(unsigned int) s_ptr->p + len, (unsigned int) data + length); |
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return; |
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} |
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|
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home = getenv("HOME"); |
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if (home == NULL) |
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return; |
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|
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/* set and create the directory -- if it doesn't exist. */ |
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fpath = xmalloc(strlen(home) + 11); |
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STRNCPY(fpath, home, strlen(home) + 1); |
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|
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sprintf(fpath, "%s/.rdesktop", fpath); |
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if (mkdir(fpath, 0700) == -1 && errno != EEXIST) |
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{ |
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perror("mkdir"); |
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exit(1); |
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} |
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|
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/* set the real licence filename, and put a write lock on it. */ |
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fname = xmalloc(strlen(fpath) + strlen(hostname) + 10); |
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sprintf(fname, "%s/licence.%s", fpath, hostname); |
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fnfd = open(fname, O_RDONLY); |
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if (fnfd != -1) |
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{ |
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fnfl.l_type = F_WRLCK; |
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fnfl.l_whence = SEEK_SET; |
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fnfl.l_start = 0; |
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fnfl.l_len = 1; |
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fcntl(fnfd, F_SETLK, &fnfl); |
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} |
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|
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/* create a temporary licence file */ |
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fnamewrk = xmalloc(strlen(fname) + 12); |
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for (y = 0;; y++) |
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{ |
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sprintf(fnamewrk, "%s.%lu", fname, (long unsigned int) y); |
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fnwrkfd = open(fnamewrk, O_WRONLY | O_CREAT | O_EXCL, 0600); |
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if (fnwrkfd == -1) |
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{ |
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if (errno == EINTR || errno == EEXIST) |
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continue; |
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perror("create"); |
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exit(1); |
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} |
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break; |
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} |
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/* write to the licence file */ |
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for (y = 0; y < len;) |
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{ |
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do |
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{ |
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wlen = write(fnwrkfd, s_ptr->p + y, len - y); |
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} |
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while (wlen == -1 && errno == EINTR); |
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if (wlen < 1) |
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{ |
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perror("write"); |
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unlink(fnamewrk); |
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exit(1); |
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} |
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y += wlen; |
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} |
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|
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/* close the file and rename it to fname */ |
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if (close(fnwrkfd) == -1) |
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{ |
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perror("close"); |
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unlink(fnamewrk); |
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exit(1); |
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} |
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if (rename(fnamewrk, fname) == -1) |
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{ |
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perror("rename"); |
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unlink(fnamewrk); |
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exit(1); |
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} |
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/* close the file lock on fname */ |
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if (fnfd != -1) |
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{ |
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fnfl.l_type = F_UNLCK; |
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fnfl.l_whence = SEEK_SET; |
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fnfl.l_start = 0; |
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fnfl.l_len = 1; |
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fcntl(fnfd, F_SETLK, &fnfl); |
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close(fnfd); |
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} |
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|
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} |
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|
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/* Generate a session key and RC4 keys, given client and server randoms */ |
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static void |
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licence_generate_keys(uint8 * client_key, uint8 * server_key, uint8 * client_rsa) |
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{ |
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uint8 session_key[48]; |
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uint8 temp_hash[48]; |
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|
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/* Generate session key - two rounds of sec_hash_48 */ |
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sec_hash_48(temp_hash, client_rsa, client_key, server_key, 65); |
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sec_hash_48(session_key, temp_hash, server_key, client_key, 65); |
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|
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/* Store first 16 bytes of session key, for generating signatures */ |
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memcpy(licence_sign_key, session_key, 16); |
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|
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/* Generate RC4 key */ |
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sec_hash_16(licence_key, &session_key[16], client_key, server_key); |
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} |
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|
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static void |
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licence_generate_hwid(uint8 * hwid) |
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{ |
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buf_out_uint32(hwid, 2); |
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strncpy((char *) (hwid + 4), hostname, LICENCE_HWID_SIZE - 4); |
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} |
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|
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/* Present an existing licence to the server */ |
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static void |
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licence_present(uint8 * client_random, uint8 * rsa_data, |
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uint8 * licence_data, int licence_size, uint8 * hwid, uint8 * signature) |
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{ |
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uint32 sec_flags = SEC_LICENCE_NEG; |
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uint16 length = |
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16 + SEC_RANDOM_SIZE + SEC_MODULUS_SIZE + SEC_PADDING_SIZE + |
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licence_size + LICENCE_HWID_SIZE + LICENCE_SIGNATURE_SIZE; |
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STREAM s; |
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|
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s = sec_init(sec_flags, length + 4); |
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|
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out_uint16_le(s, LICENCE_TAG_PRESENT); |
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out_uint16_le(s, length); |
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|
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out_uint32_le(s, 1); |
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out_uint16(s, 0); |
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out_uint16_le(s, 0x0201); |
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|
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out_uint8p(s, client_random, SEC_RANDOM_SIZE); |
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out_uint16(s, 0); |
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out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE)); |
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out_uint8p(s, rsa_data, SEC_MODULUS_SIZE); |
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out_uint8s(s, SEC_PADDING_SIZE); |
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|
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out_uint16_le(s, 1); |
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out_uint16_le(s, licence_size); |
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out_uint8p(s, licence_data, licence_size); |
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|
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out_uint16_le(s, 1); |
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out_uint16_le(s, LICENCE_HWID_SIZE); |
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out_uint8p(s, hwid, LICENCE_HWID_SIZE); |
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|
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out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE); |
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|
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s_mark_end(s); |
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sec_send(s, sec_flags); |
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} |
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|
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/* Send a licence request packet */ |
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static void |
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licence_send_request(uint8 * client_random, uint8 * rsa_data, char *user, char *host) |
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{ |
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uint32 sec_flags = SEC_LICENCE_NEG; |
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uint16 userlen = strlen(user) + 1; |
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uint16 hostlen = strlen(host) + 1; |
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uint16 length = 128 + userlen + hostlen; |
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STREAM s; |
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|
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s = sec_init(sec_flags, length + 2); |
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|
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out_uint16_le(s, LICENCE_TAG_REQUEST); |
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out_uint16_le(s, length); |
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|
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out_uint32_le(s, 1); |
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out_uint16(s, 0); |
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out_uint16_le(s, 0xff01); |
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|
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out_uint8p(s, client_random, SEC_RANDOM_SIZE); |
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out_uint16(s, 0); |
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out_uint16_le(s, (SEC_MODULUS_SIZE + SEC_PADDING_SIZE)); |
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out_uint8p(s, rsa_data, SEC_MODULUS_SIZE); |
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out_uint8s(s, SEC_PADDING_SIZE); |
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|
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out_uint16(s, LICENCE_TAG_USER); |
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out_uint16(s, userlen); |
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out_uint8p(s, user, userlen); |
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|
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out_uint16(s, LICENCE_TAG_HOST); |
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out_uint16(s, hostlen); |
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out_uint8p(s, host, hostlen); |
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|
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s_mark_end(s); |
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sec_send(s, sec_flags); |
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} |
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|
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/* Process a licence demand packet */ |
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static void |
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licence_process_demand(STREAM s) |
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{ |
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uint8 null_data[SEC_MODULUS_SIZE]; |
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uint8 *server_random; |
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uint8 signature[LICENCE_SIGNATURE_SIZE]; |
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uint8 hwid[LICENCE_HWID_SIZE]; |
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uint8 *licence_data; |
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int licence_size; |
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RC4_KEY crypt_key; |
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|
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/* Retrieve the server random from the incoming packet */ |
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in_uint8p(s, server_random, SEC_RANDOM_SIZE); |
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|
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/* We currently use null client keys. This is a bit naughty but, hey, |
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the security of licence negotiation isn't exactly paramount. */ |
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memset(null_data, 0, sizeof(null_data)); |
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licence_generate_keys(null_data, server_random, null_data); |
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|
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licence_size = load_licence(&licence_data); |
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if (licence_size != -1) |
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{ |
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/* Generate a signature for the HWID buffer */ |
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licence_generate_hwid(hwid); |
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sec_sign(signature, 16, licence_sign_key, 16, hwid, sizeof(hwid)); |
328 |
|
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/* Now encrypt the HWID */ |
330 |
RC4_set_key(&crypt_key, 16, licence_key); |
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RC4(&crypt_key, sizeof(hwid), hwid, hwid); |
332 |
|
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licence_present(null_data, null_data, licence_data, licence_size, hwid, signature); |
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xfree(licence_data); |
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return; |
336 |
} |
337 |
|
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licence_send_request(null_data, null_data, username, hostname); |
339 |
} |
340 |
|
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/* Send an authentication response packet */ |
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static void |
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licence_send_authresp(uint8 * token, uint8 * crypt_hwid, uint8 * signature) |
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{ |
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uint32 sec_flags = SEC_LICENCE_NEG; |
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uint16 length = 58; |
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STREAM s; |
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|
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s = sec_init(sec_flags, length + 2); |
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|
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out_uint16_le(s, LICENCE_TAG_AUTHRESP); |
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out_uint16_le(s, length); |
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|
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out_uint16_le(s, 1); |
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out_uint16_le(s, LICENCE_TOKEN_SIZE); |
356 |
out_uint8p(s, token, LICENCE_TOKEN_SIZE); |
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|
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out_uint16_le(s, 1); |
359 |
out_uint16_le(s, LICENCE_HWID_SIZE); |
360 |
out_uint8p(s, crypt_hwid, LICENCE_HWID_SIZE); |
361 |
|
362 |
out_uint8p(s, signature, LICENCE_SIGNATURE_SIZE); |
363 |
|
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s_mark_end(s); |
365 |
sec_send(s, sec_flags); |
366 |
} |
367 |
|
368 |
/* Parse an authentication request packet */ |
369 |
static BOOL |
370 |
licence_parse_authreq(STREAM s, uint8 ** token, uint8 ** signature) |
371 |
{ |
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uint16 tokenlen; |
373 |
|
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in_uint8s(s, 6); /* unknown: f8 3d 15 00 04 f6 */ |
375 |
|
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in_uint16_le(s, tokenlen); |
377 |
if (tokenlen != LICENCE_TOKEN_SIZE) |
378 |
{ |
379 |
error("token len %d\n", tokenlen); |
380 |
return False; |
381 |
} |
382 |
|
383 |
in_uint8p(s, *token, tokenlen); |
384 |
in_uint8p(s, *signature, LICENCE_SIGNATURE_SIZE); |
385 |
|
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return s_check_end(s); |
387 |
} |
388 |
|
389 |
/* Process an authentication request packet */ |
390 |
static void |
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licence_process_authreq(STREAM s) |
392 |
{ |
393 |
uint8 *in_token, *in_sig; |
394 |
uint8 out_token[LICENCE_TOKEN_SIZE], decrypt_token[LICENCE_TOKEN_SIZE]; |
395 |
uint8 hwid[LICENCE_HWID_SIZE], crypt_hwid[LICENCE_HWID_SIZE]; |
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uint8 sealed_buffer[LICENCE_TOKEN_SIZE + LICENCE_HWID_SIZE]; |
397 |
uint8 out_sig[LICENCE_SIGNATURE_SIZE]; |
398 |
RC4_KEY crypt_key; |
399 |
|
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/* Parse incoming packet and save the encrypted token */ |
401 |
licence_parse_authreq(s, &in_token, &in_sig); |
402 |
memcpy(out_token, in_token, LICENCE_TOKEN_SIZE); |
403 |
|
404 |
/* Decrypt the token. It should read TEST in Unicode. */ |
405 |
RC4_set_key(&crypt_key, 16, licence_key); |
406 |
RC4(&crypt_key, LICENCE_TOKEN_SIZE, in_token, decrypt_token); |
407 |
|
408 |
/* Generate a signature for a buffer of token and HWID */ |
409 |
licence_generate_hwid(hwid); |
410 |
memcpy(sealed_buffer, decrypt_token, LICENCE_TOKEN_SIZE); |
411 |
memcpy(sealed_buffer + LICENCE_TOKEN_SIZE, hwid, LICENCE_HWID_SIZE); |
412 |
sec_sign(out_sig, 16, licence_sign_key, 16, sealed_buffer, sizeof(sealed_buffer)); |
413 |
|
414 |
/* Now encrypt the HWID */ |
415 |
RC4_set_key(&crypt_key, 16, licence_key); |
416 |
RC4(&crypt_key, LICENCE_HWID_SIZE, hwid, crypt_hwid); |
417 |
|
418 |
licence_send_authresp(out_token, crypt_hwid, out_sig); |
419 |
} |
420 |
|
421 |
/* Process an licence issue packet */ |
422 |
static void |
423 |
licence_process_issue(STREAM s) |
424 |
{ |
425 |
RC4_KEY crypt_key; |
426 |
uint32 length; |
427 |
uint16 check; |
428 |
|
429 |
in_uint8s(s, 2); /* 3d 45 - unknown */ |
430 |
in_uint16_le(s, length); |
431 |
if (!s_check_rem(s, length)) |
432 |
return; |
433 |
|
434 |
RC4_set_key(&crypt_key, 16, licence_key); |
435 |
RC4(&crypt_key, length, s->p, s->p); |
436 |
|
437 |
in_uint16(s, check); |
438 |
if (check != 0) |
439 |
return; |
440 |
|
441 |
licence_issued = True; |
442 |
save_licence(s->p, length - 2); |
443 |
} |
444 |
|
445 |
/* Process a licence packet */ |
446 |
void |
447 |
licence_process(STREAM s) |
448 |
{ |
449 |
uint16 tag; |
450 |
|
451 |
in_uint16_le(s, tag); |
452 |
in_uint8s(s, 2); /* length */ |
453 |
|
454 |
switch (tag) |
455 |
{ |
456 |
case LICENCE_TAG_DEMAND: |
457 |
licence_process_demand(s); |
458 |
break; |
459 |
|
460 |
case LICENCE_TAG_AUTHREQ: |
461 |
licence_process_authreq(s); |
462 |
break; |
463 |
|
464 |
case LICENCE_TAG_ISSUE: |
465 |
licence_process_issue(s); |
466 |
break; |
467 |
|
468 |
case LICENCE_TAG_REISSUE: |
469 |
break; |
470 |
|
471 |
case LICENCE_TAG_RESULT: |
472 |
break; |
473 |
|
474 |
default: |
475 |
unimpl("licence tag 0x%x\n", tag); |
476 |
} |
477 |
} |