123 lines
3.8 KiB
C
123 lines
3.8 KiB
C
/*
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File: file_ttf.c
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Copyright (C) 2009 Christophe GRENIER <grenier@cgsecurity.org>
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This software 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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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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You should have received a copy of the GNU General Public License along
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with this program; if not, write the Free Software Foundation, Inc., 51
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Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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#ifdef HAVE_TIME_H
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#include <time.h>
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#endif
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#include <stdio.h>
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#include "types.h"
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#include "common.h"
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#include "filegen.h"
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static void register_header_check_ttf(file_stat_t *file_stat);
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static int header_check_ttf(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);
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const file_hint_t file_hint_ttf= {
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.extension="ttf",
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.description="TrueType Font",
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.min_header_distance=0,
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.max_filesize=PHOTOREC_MAX_FILE_SIZE,
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.recover=1,
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.enable_by_default=1,
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.register_header_check=®ister_header_check_ttf
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};
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static const unsigned char header_ttf[5]= {0x00 , 0x01, 0x00, 0x00, 0x00};
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static void register_header_check_ttf(file_stat_t *file_stat)
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{
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register_header_check(0, header_ttf, sizeof(header_ttf), &header_check_ttf, file_stat);
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}
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/*
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* http://www.microsoft.com/typography/otspec/otff.htm
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*/
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struct ttf_offset_table
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{
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int32_t sfnt_version;
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uint16_t numTables;
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uint16_t searchRange;
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uint16_t entrySelector;
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uint16_t rangeShift;
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};
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struct ttf_table_directory
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{
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uint32_t tag;
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uint32_t checkSum;
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uint32_t offset; /* Offset from beginning of TrueType font file. */
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uint32_t length; /* Length of this table. */
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};
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static unsigned int td_ilog2(unsigned int v)
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{
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unsigned int l = 0;
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while(v >>= 1)
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l++;
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return l;
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}
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static int header_check_ttf(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)
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{
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const struct ttf_offset_table *ttf=(const struct ttf_offset_table *)buffer;
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unsigned int numTables;
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if(memcmp(buffer, header_ttf, sizeof(header_ttf))!=0)
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return 0;
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numTables=be16(ttf->numTables);
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/* searchRange (Maximum power of 2 <= numTables) x 16.
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* entrySelector Log2(maximum power of 2 <= numTables).
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* rangeShift NumTables x 16-searchRange.
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* */
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if(td_ilog2(numTables) != be16(ttf->entrySelector))
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return 0;
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if((16<<be16(ttf->entrySelector)) != be16(ttf->searchRange))
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return 0;
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if(numTables * 16 != (unsigned int)be16(ttf->rangeShift)+be16(ttf->searchRange))
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return 0;
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reset_file_recovery(file_recovery_new);
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file_recovery_new->extension=file_hint_ttf.extension;
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if(sizeof(struct ttf_offset_table) + numTables * sizeof(struct ttf_table_directory)
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<= buffer_size)
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{
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const struct ttf_table_directory*ttf_dir=(const struct ttf_table_directory*)(ttf+1);
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uint64_t max_offset=0;
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unsigned int i;
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for(i=0; i<numTables; i++,ttf_dir++)
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{
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/* | 0x3: align the end of the table */
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const uint64_t new_offset=(be32(ttf_dir->offset) + be32(ttf_dir->length))|0x3;
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if(max_offset < new_offset)
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max_offset=new_offset;
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}
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file_recovery_new->calculated_file_size=max_offset;
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file_recovery_new->data_check=&data_check_size;
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file_recovery_new->file_check=&file_check_size;
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}
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return 1;
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}
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