-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 - - Orange Bat advisory - Name : VLC 0.8.6i Class : Heap overflow Published : 2008-08-16 Credit : g_ (g_ # orange-bat # com) - - Details - \modules\demux\tta.c #define TTA_FRAMETIME 1.04489795918367346939 . . . int i_seektable_size = 0, i; . . . /* Read the metadata */ es_format_Init( &fmt, AUDIO_ES, VLC_FOURCC( 'T', 'T', 'A', '1' ) ); fmt.audio.i_channels = GetWLE( &p_header[6] ); fmt.audio.i_bitspersample = GetWLE( &p_header[8] ); [1] fmt.audio.i_rate = GetDWLE( &p_header[10] ); p_sys->i_datalength = GetDWLE( &p_header[14] ); p_sys->i_framelength = TTA_FRAMETIME * fmt.audio.i_rate; [2] p_sys->i_totalframes = p_sys->i_datalength / p_sys->i_framelength + ((p_sys->i_datalength % p_sys->i_framelength) ? 1 : 0); p_sys->i_currentframe = 0; [3] i_seektable_size = sizeof(uint32_t)*p_sys->i_totalframes; p_seektable = (uint8_t *)malloc( i_seektable_size ); stream_Read( p_demux->s, p_seektable, i_seektable_size ); p_sys->pi_seektable = (uint32_t *)malloc(i_seektable_size); for( i = 0; i < p_sys->i_totalframes; i++ ) [4] p_sys->pi_seektable[i] = GetDWLE( &p_seektable[i*4] ); [1] - we can set i_rate to 1 [2] - i_framelength = 1 (look for constant definition, it's ~1), so i_totalframes = i_datalength [3] - because we can set i_datalength to 2^30 and bacause i_totalframes = i_datalength, multiplication will overflow [4] - i_totalframes is positive (highest bit not set), so this loop will spin 2^30 times, overwriting everything with data from the heap. unfortunate thing is we have little control over what is written. - - Proof of concept - http://www.orange-bat.com/adv/2008/vlc.dos.tta - - PGP - All advisories from Orange Bat are signed. You can find our public key here: http://www.orange-bat.com/g_.asc - - Disclaimer - This document and all the information it contains is provided "as is", without any warranty. Orange Bat is not responsible for the misuse of the information provided in this advisory. The advisory is provided for educational purposes only. Permission is hereby granted to redistribute this advisory, providing that no changes are made and that the copyright notices and disclaimers remain intact. (c) 2008 www.orange-bat.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) iEYEARECAAYFAkimwoYACgkQIUHRVUfOLgW8hgCgmPcqqIlcLQpmH8u6wB2fVOHs Zv4AoNNYWhzdknZOnPuChysoak1rMRsx =4K3f -----END PGP SIGNATURE-----