/* libdvdcss.c: DVD reading library. * * Authors: Stéphane Borel * Samuel Hocevar * Håkan Hjort * * Copyright (C) 1998-2002 VideoLAN * $Id$ * * 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., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */ /** * \mainpage libdvdcss developer documentation * * \section intro Introduction * * \e libdvdcss is a simple library designed for accessing DVDs like a block * device without having to bother about the decryption. The important features * are: * \li portability: currently supported platforms are GNU/Linux, FreeBSD, * NetBSD, OpenBSD, BSD/OS, BeOS, Windows 95/98, Windows NT/2000, MacOS X, * Solaris, HP-UX and OS/2. * \li adaptability: unlike most similar projects, libdvdcss doesn't require * the region of your drive to be set and will try its best to read from * the disc even in the case of a region mismatch. * \li simplicity: a DVD player can be built around the \e libdvdcss API using * no more than 4 or 5 library calls. * * \e libdvdcss is free software, released under the General Public License. * This ensures that \e libdvdcss remains free and used only with free * software. * * \section api The libdvdcss API * * The complete \e libdvdcss programming interface is documented in the * dvdcss.h file. * * \section env Environment variables * * Some environment variables can be used to change the behaviour of * \e libdvdcss without having to modify the program which uses it. These * variables are: * * \li \b DVDCSS_VERBOSE: sets the verbosity level. * - \c 0 outputs no messages at all. * - \c 1 outputs error messages to stderr. * - \c 2 outputs error messages and debug messages to stderr. * * \li \b DVDCSS_METHOD: sets the authentication and decryption method * that \e libdvdcss will use to read scrambled discs. Can be one * of \c title, \c key or \c disc. * - \c key is the default method. \e libdvdcss will use a set of * calculated player keys to try and get the disc key. This can fail * if the drive does not recognize any of the player keys. * - \c disc is a fallback method when \c key has failed. Instead of * using player keys, \e libdvdcss will crack the disc key using * a brute force algorithm. This process is CPU intensive and requires * 64 MB of memory to store temporary data. * - \c title is the fallback when all other methods have failed. It does * not rely on a key exchange with the DVD drive, but rather uses a * crypto attack to guess the title key. On rare cases this may fail * because there is not enough encrypted data on the disc to perform * a statistical attack, but in the other hand it is the only way to * decrypt a DVD stored on a hard disc, or a DVD with the wrong region * on an RPC2 drive. * * \li \b DVDCSS_RAW_DEVICE: specify the raw device to use. * */ /* * Preamble */ #include "config.h" #include #include #include #include #include #include #ifdef HAVE_UNISTD_H # include #endif #include "dvdcss.h" #include "common.h" #include "css.h" #include "libdvdcss.h" #include "ioctl.h" #include "device.h" /** * \brief Symbol for version checks. * * The name of this symbol contains the library major number, which makes it * easy to check which \e libdvdcss development headers are installed on the * system with tools such as autoconf. * * The variable itself contains the exact version number of the library, * which can be useful for specific feature needs. */ char * dvdcss_interface_2 = VERSION; char * dvdcss_cache_dir = NULL; /** * \brief Open a DVD device or directory and return a dvdcss instance. * * \param psz_target a string containing the target name, for instance * "/dev/hdc" or "E:". * \return a handle to a dvdcss instance or NULL on error. * * Initialize the \e libdvdcss library and open the requested DVD device or * directory. \e libdvdcss checks whether ioctls can be performed on the disc, * and when possible, the disc key is retrieved. * * dvdcss_open() returns a handle to be used for all subsequent \e libdvdcss * calls. If an error occured, NULL is returned. */ extern dvdcss_t dvdcss_open ( char *psz_target ) { int i_ret; char *psz_method = getenv( "DVDCSS_METHOD" ); char *psz_verbose = getenv( "DVDCSS_VERBOSE" ); #ifndef WIN32 char *psz_raw_device = getenv( "DVDCSS_RAW_DEVICE" ); #endif dvdcss_t dvdcss; /* * Allocate the library structure */ dvdcss = malloc( sizeof( struct dvdcss_s ) ); if( dvdcss == NULL ) { return NULL; } /* * Initialize structure with default values */ #ifndef WIN32 dvdcss->i_raw_fd = -1; #endif dvdcss->p_titles = NULL; dvdcss->psz_device = (char *)strdup( psz_target ); dvdcss->psz_error = "no error"; dvdcss->i_method = DVDCSS_METHOD_KEY; dvdcss->b_debug = 0; dvdcss->b_errors = 0; dvdcss->psz_cache = NULL; /* * Find verbosity from DVDCSS_VERBOSE environment variable */ if( psz_verbose != NULL ) { switch( atoi( psz_verbose ) ) { case 2: dvdcss->b_debug = 1; case 1: dvdcss->b_errors = 1; case 0: break; } } /* * Find method from DVDCSS_METHOD environment variable */ if( psz_method != NULL ) { if( !strncmp( psz_method, "key", 4 ) ) { dvdcss->i_method = DVDCSS_METHOD_KEY; } else if( !strncmp( psz_method, "disc", 5 ) ) { dvdcss->i_method = DVDCSS_METHOD_DISC; } else if( !strncmp( psz_method, "title", 5 ) ) { dvdcss->i_method = DVDCSS_METHOD_TITLE; } else { _dvdcss_error( dvdcss, "unknown decrypt method, please choose " "from 'title', 'key' or 'disc'" ); free( dvdcss->psz_device ); free( dvdcss ); return NULL; } } if(!dvdcss_cache_dir) dvdcss_cache_dir = getenv( "DVDCSS_CACHE" ); /* * Open device */ i_ret = _dvdcss_open( dvdcss ); if( i_ret < 0 ) { free( dvdcss->psz_device ); free( dvdcss ); return NULL; } dvdcss->b_scrambled = 1; /* Assume the worst */ dvdcss->b_ioctls = _dvdcss_use_ioctls( dvdcss ); if( dvdcss->b_ioctls ) { i_ret = _dvdcss_test( dvdcss ); if( i_ret < 0 ) { /* Disable the CSS ioctls and hope that it works? */ _dvdcss_debug( dvdcss, "could not check whether the disc was scrambled" ); dvdcss->b_ioctls = 0; } else { _dvdcss_debug( dvdcss, i_ret ? "disc is scrambled" : "disc is unscrambled" ); dvdcss->b_scrambled = i_ret; } } /* If disc is CSS protected and the ioctls work, authenticate the drive */ if( dvdcss->b_scrambled && dvdcss->b_ioctls ) { i_ret = _dvdcss_disckey( dvdcss ); if( i_ret < 0 ) { _dvdcss_close( dvdcss ); free( dvdcss->psz_device ); free( dvdcss ); return NULL; } } #ifndef WIN32 if( psz_raw_device != NULL ) { _dvdcss_raw_open( dvdcss, psz_raw_device ); } #endif /* if the CACHE is enabled, extract some unique disc ID */ if(dvdcss_cache_dir){ char* disc_id=NULL; /*char title_name[64];*/ char sector[DVDCSS_BLOCK_SIZE]; // 32768+40 -> disc title (32 uppercase chars) // 32768+813 -> disc manufacturing date + serial no (16 digit number) _dvdcss_seek( dvdcss, 32768/DVDCSS_BLOCK_SIZE); if(_dvdcss_read( dvdcss, sector, 1) == 1){ // check disc title first: char* title_name=§or[40]; int i=31; while(i>=0 && title_name[i]<=32) i--; title_name[i+1]=0; if(strlen(title_name)>5){ disc_id=strdup(title_name); } else { // use disc date+serial: title_name=§or[813]; title_name[16]=0; for ( i=0;i<16;i++ ) if ( ( title_name[i] < '0' )||( title_name[i] > '9' ) ){ disc_id=malloc(16+4); sprintf( disc_id,"%.2X%.2X%.2X%.2X%.2X%.2X%.2X%.2X",title_name[0],title_name[1],title_name[2],title_name[3],title_name[4],title_name[5],title_name[6],title_name[7] ); break; } if(!disc_id) disc_id=strdup(title_name); } if(disc_id){ // yeah, we have a disc name/id, let's set up cache path: /*char* dir;*/ dvdcss->psz_cache = malloc(strlen(dvdcss_cache_dir)+strlen(disc_id)+4); sprintf(dvdcss->psz_cache,"%s/%s",dvdcss_cache_dir,disc_id); mkdir( dvdcss->psz_cache,493 ); free(disc_id); fprintf(stderr,"Using CSS Key-cache dir: %s\n",dvdcss->psz_cache); } } } return dvdcss; } /** * \brief Return a string containing the latest error that occured in the * given \e libdvdcss instance. * * \param dvdcss a \e libdvdcss instance. * \return a null-terminated string containing the latest error message. * * This function returns a constant string containing the latest error that * occured in \e libdvdcss. It can be used to format error messages at your * convenience in your application. */ extern char * dvdcss_error ( dvdcss_t dvdcss ) { return dvdcss->psz_error; } /** * \brief Seek in the disc and change the current key if requested. * * \param dvdcss a \e libdvdcss instance. * \param i_blocks an absolute block offset to seek to. * \param i_flags #DVDCSS_NOFLAGS, optionally ored with one of #DVDCSS_SEEK_KEY * or #DVDCSS_SEEK_MPEG. * \return the new position in blocks, or a negative value in case an error * happened. * * This function seeks to the requested position, in logical blocks. * * You typically set \p i_flags to #DVDCSS_NOFLAGS when seeking in a .IFO. * * If #DVDCSS_SEEK_MPEG is specified in \p i_flags and if \e libdvdcss finds it * reasonable to do so (ie, if the dvdcss method is not "title"), the current * title key will be checked and a new one will be calculated if necessary. * This flag is typically used when reading data from a VOB. * * If #DVDCSS_SEEK_KEY is specified, the title key will be always checked, * even with the "title" method. This is equivalent to using the now * deprecated dvdcss_title() call. This flag is typically used when seeking * in a new title. */ extern int dvdcss_seek ( dvdcss_t dvdcss, int i_blocks, int i_flags ) { /* title cracking method is too slow to be used at each seek */ if( ( ( i_flags & DVDCSS_SEEK_MPEG ) && ( dvdcss->i_method != DVDCSS_METHOD_TITLE ) ) || ( i_flags & DVDCSS_SEEK_KEY ) ) { /* check the title key */ if( _dvdcss_title( dvdcss, i_blocks ) ) { return -1; } } return _dvdcss_seek( dvdcss, i_blocks ); } /** * \brief Read from the disc and decrypt data if requested. * * \param dvdcss a \e libdvdcss instance. * \param p_buffer a buffer that will contain the data read from the disc. * \param i_blocks the amount of blocks to read. * \param i_flags #DVDCSS_NOFLAGS, optionally ored with #DVDCSS_READ_DECRYPT. * \return the amount of blocks read, or a negative value in case an * error happened. * * This function reads \p i_blocks logical blocks from the DVD. * * You typically set \p i_flags to #DVDCSS_NOFLAGS when reading data from a * .IFO file on the DVD. * * If #DVDCSS_READ_DECRYPT is specified in \p i_flags, dvdcss_read() will * automatically decrypt scrambled sectors. This flag is typically used when * reading data from a .VOB file on the DVD. It has no effect on unscrambled * discs or unscrambled sectors, and can be safely used on those. * * \warning dvdcss_read() expects to be able to write \p i_blocks * * #DVDCSS_BLOCK_SIZE bytes in \p p_buffer. */ extern int dvdcss_read ( dvdcss_t dvdcss, void *p_buffer, int i_blocks, int i_flags ) { int i_ret, i_index; i_ret = _dvdcss_read( dvdcss, p_buffer, i_blocks ); if( i_ret <= 0 || !dvdcss->b_scrambled || !(i_flags & DVDCSS_READ_DECRYPT) ) { return i_ret; } if( ! memcmp( dvdcss->css.p_title_key, "\0\0\0\0\0", 5 ) ) { /* For what we believe is an unencrypted title, * check that there are no encrypted blocks */ for( i_index = i_ret; i_index; i_index-- ) { if( ((u8*)p_buffer)[0x14] & 0x30 ) { _dvdcss_error( dvdcss, "no key but found encrypted block" ); /* Only return the initial range of unscrambled blocks? */ /* or fail completely? return 0; */ break; } p_buffer = (void *) ((u8 *)p_buffer + DVDCSS_BLOCK_SIZE); } } else { /* Decrypt the blocks we managed to read */ for( i_index = i_ret; i_index; i_index-- ) { _dvdcss_unscramble( dvdcss->css.p_title_key, p_buffer ); ((u8*)p_buffer)[0x14] &= 0x8f; p_buffer = (void *) ((u8 *)p_buffer + DVDCSS_BLOCK_SIZE); } } return i_ret; } /** * \brief Read from the disc into multiple buffers and decrypt data if * requested. * * \param dvdcss a \e libdvdcss instance. * \param p_iovec a pointer to an array of iovec structures that will contain * the data read from the disc. * \param i_blocks the amount of blocks to read. * \param i_flags #DVDCSS_NOFLAGS, optionally ored with #DVDCSS_READ_DECRYPT. * \return the amount of blocks read, or a negative value in case an * error happened. * * This function reads \p i_blocks logical blocks from the DVD and writes them * to an array of iovec structures. * * You typically set \p i_flags to #DVDCSS_NOFLAGS when reading data from a * .IFO file on the DVD. * * If #DVDCSS_READ_DECRYPT is specified in \p i_flags, dvdcss_readv() will * automatically decrypt scrambled sectors. This flag is typically used when * reading data from a .VOB file on the DVD. It has no effect on unscrambled * discs or unscrambled sectors, and can be safely used on those. * * \warning dvdcss_readv() expects to be able to write \p i_blocks * * #DVDCSS_BLOCK_SIZE bytes in the buffers pointed by \p p_iovec. * Moreover, all iov_len members of the iovec structures should be * multiples of #DVDCSS_BLOCK_SIZE. */ extern int dvdcss_readv ( dvdcss_t dvdcss, void *p_iovec, int i_blocks, int i_flags ) { struct iovec *_p_iovec = (struct iovec *)p_iovec; int i_ret, i_index; void *iov_base; size_t iov_len; i_ret = _dvdcss_readv( dvdcss, _p_iovec, i_blocks ); if( i_ret <= 0 || !dvdcss->b_scrambled || !(i_flags & DVDCSS_READ_DECRYPT) ) { return i_ret; } /* Initialize loop for decryption */ iov_base = _p_iovec->iov_base; iov_len = _p_iovec->iov_len; /* Decrypt the blocks we managed to read */ for( i_index = i_ret; i_index; i_index-- ) { /* Check that iov_len is a multiple of 2048 */ if( iov_len & 0x7ff ) { return -1; } while( iov_len == 0 ) { _p_iovec++; iov_base = _p_iovec->iov_base; iov_len = _p_iovec->iov_len; } _dvdcss_unscramble( dvdcss->css.p_title_key, iov_base ); ((u8*)iov_base)[0x14] &= 0x8f; iov_base = (void *) ((u8*)iov_base + DVDCSS_BLOCK_SIZE); iov_len -= DVDCSS_BLOCK_SIZE; } return i_ret; } /** * \brief Close the DVD and clean up the library. * * \param dvdcss a \e libdvdcss instance. * \return zero in case of success, a negative value otherwise. * * This function closes the DVD device and frees all the memory allocated * by \e libdvdcss. On return, the #dvdcss_t is invalidated and may not be * used again. */ extern int dvdcss_close ( dvdcss_t dvdcss ) { dvd_title_t *p_title; int i_ret; /* Free our list of keys */ p_title = dvdcss->p_titles; while( p_title ) { dvd_title_t *p_tmptitle = p_title->p_next; free( p_title ); p_title = p_tmptitle; } i_ret = _dvdcss_close( dvdcss ); if( i_ret < 0 ) { return i_ret; } free( dvdcss->psz_device ); free( dvdcss ); return 0; } /* * Deprecated. See dvdcss_seek(). */ #undef dvdcss_title extern int dvdcss_title ( dvdcss_t dvdcss, int i_block ) { return _dvdcss_title( dvdcss, i_block ); }