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More robust mp3 detection

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This commit is contained in:
Christophe Grenier 2008-05-27 00:17:46 +02:00
parent 9d6244e897
commit 86d7021cbc
1 changed files with 52 additions and 52 deletions
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104
src/file_mp3.c
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@ -2,7 +2,7 @@
File: file_mp3.c
Copyright (C) 1998-2007 Christophe GRENIER <grenier@cgsecurity.org>
Copyright (C) 1998-2008 Christophe GRENIER <grenier@cgsecurity.org>
This software is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@ -155,6 +155,7 @@ static int header_check_id3(const unsigned char *buffer, const unsigned int buff
static int header_check_mp3(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
{
unsigned int potential_frame_offset=0;
unsigned int nbr=0;
/*
A Frame sync 11 (length in bits)
B MPEG audio version (MPEG-1, 2, etc.) 2
@ -171,65 +172,64 @@ static int header_check_mp3(const unsigned char *buffer, const unsigned int buff
((potential_frame_offset==0 && file_recovery->file_stat->file_hint==&file_hint_mp3)||
file_recovery->file_stat->file_hint==&file_hint_mkv))
return 0;
if(buffer[potential_frame_offset+0]==0xFF &&
((buffer[potential_frame_offset+1]&0xFE)==0xFA ||
(buffer[potential_frame_offset+1]&0xFE)==0xF2 ||
(buffer[potential_frame_offset+1]&0xFE)==0xE2))
if(!(buffer[potential_frame_offset+0]==0xFF &&
((buffer[potential_frame_offset+1]&0xFE)==0xFA ||
(buffer[potential_frame_offset+1]&0xFE)==0xF2 ||
(buffer[potential_frame_offset+1]&0xFE)==0xE2)))
return 0;
while(potential_frame_offset+1 < buffer_size &&
potential_frame_offset+1 < 2048)
{
unsigned int mpeg_version =(buffer[potential_frame_offset+1]>>3)&0x03;
unsigned int mpeg_layer =(buffer[potential_frame_offset+1]>>1)&0x03;
unsigned int bit_rate_key =(buffer[potential_frame_offset+2]>>4)&0x0F;
unsigned int sampling_rate_key=(buffer[potential_frame_offset+2]>>2)&0x03;
unsigned int padding =(buffer[potential_frame_offset+2]>>1)&0x01;
unsigned int bit_rate= bit_rate_table[mpeg_version][mpeg_layer][bit_rate_key]*1000;
unsigned int sample_rate=sample_rate_table[mpeg_version][sampling_rate_key];
unsigned int frameLengthInBytes=0;
if(sample_rate>0 && bit_rate>0)
if(buffer[potential_frame_offset+0]!=0xFF)
return 0;
{
if(mpeg_layer==MPEG_L3)
unsigned int mpeg_version =(buffer[potential_frame_offset+1]>>3)&0x03;
unsigned int mpeg_layer =(buffer[potential_frame_offset+1]>>1)&0x03;
unsigned int bit_rate_key =(buffer[potential_frame_offset+2]>>4)&0x0F;
unsigned int sampling_rate_key=(buffer[potential_frame_offset+2]>>2)&0x03;
unsigned int padding =(buffer[potential_frame_offset+2]>>1)&0x01;
unsigned int bit_rate= bit_rate_table[mpeg_version][mpeg_layer][bit_rate_key]*1000;
unsigned int sample_rate=sample_rate_table[mpeg_version][sampling_rate_key];
unsigned int frameLengthInBytes=0;
if(sample_rate>0 && bit_rate>0)
{
if(mpeg_version==MPEG_V1)
if(mpeg_layer==MPEG_L3)
{
if(mpeg_version==MPEG_V1)
frameLengthInBytes = 144 * bit_rate / sample_rate + padding;
else
frameLengthInBytes = 72 * bit_rate / sample_rate + padding;
}
else if(mpeg_layer==MPEG_L2)
frameLengthInBytes = 144 * bit_rate / sample_rate + padding;
else
frameLengthInBytes = 72 * bit_rate / sample_rate + padding;
}
else if(mpeg_layer==MPEG_L2)
frameLengthInBytes = 144 * bit_rate / sample_rate + padding;
else
frameLengthInBytes = (12 * bit_rate / sample_rate + padding)*4;
}
/*
log_info("bit_rate=%u\n",bit_rate);
log_info("sample_rate=%u\n",sample_rate);
log_info("padding=%u\n", padding);
log_info("frameLengthInBytes=%u\n",frameLengthInBytes);
*/
if(frameLengthInBytes==0)
return 0;
potential_frame_offset+=frameLengthInBytes;
/*
log_info("potential_frame_offset at 0x%x\n", potential_frame_offset);
*/
if(potential_frame_offset+1 < buffer_size)
{
if(buffer[potential_frame_offset+0]==0xFF &&
((buffer[potential_frame_offset+1]&0xFE)==0xFA ||
(buffer[potential_frame_offset+1]&0xFE)==0xF2 ||
(buffer[potential_frame_offset+1]&0xFE)==0xE2))
{
/*
log_info("header_check_mp3 mp3 found\n");
*/
reset_file_recovery(file_recovery_new);
file_recovery_new->calculated_file_size=potential_frame_offset;
file_recovery_new->min_filesize=287;
file_recovery_new->data_check=&data_check_mp3;
file_recovery_new->extension=file_hint_mp3.extension;
file_recovery_new->file_check=&file_check_size;
return 1;
frameLengthInBytes = (12 * bit_rate / sample_rate + padding)*4;
}
#ifdef DEBUG_MP3
log_info("bit_rate=%u\n",bit_rate);
log_info("sample_rate=%u\n",sample_rate);
log_info("padding=%u\n", padding);
log_info("frameLengthInBytes=%u\n",frameLengthInBytes);
#endif
if(frameLengthInBytes==0)
return 0;
potential_frame_offset+=frameLengthInBytes;
nbr++;
}
}
if(nbr>1)
{
#ifdef DEBUG_MP3
log_info("header_check_mp3 mp3 found\n");
#endif
reset_file_recovery(file_recovery_new);
file_recovery_new->calculated_file_size=potential_frame_offset;
file_recovery_new->min_filesize=287;
file_recovery_new->data_check=&data_check_mp3;
file_recovery_new->extension=file_hint_mp3.extension;
file_recovery_new->file_check=&file_check_size;
return 1;
}
return 0;
}