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/*
* Copyright (C) 2006 aCaB <acab@clamav.net>
*
* 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., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif
#include "others.h"
static int doubledl(char **scur, uint8_t *mydlptr, char *buffer, uint32_t buffersize)
{
unsigned char mydl = *mydlptr;
unsigned char olddl = mydl;
mydl*=2;
if ( !(olddl & 0x7f)) {
if ( *scur < buffer || *scur >= buffer+buffersize-1 )
return -1;
olddl = **scur;
mydl = olddl*2+1;
*scur=*scur + 1;
}
*mydlptr = mydl;
return (olddl>>7)&1;
}
int cli_unfsg(char *source, char *dest, int ssize, int dsize, char **endsrc, char **enddst) {
uint8_t mydl=0x80;
uint32_t backbytes, backsize, oldback = 0;
char *csrc = source, *cdst = dest;
int oob, lostbit = 1;
/* I assume buffers size is >0 - No checking! */
*cdst++=*csrc++;
while ( 1 ) {
if ((oob=doubledl(&csrc, &mydl, source, ssize))) {
if (oob == -1)
return -1;
/* 164 */
backsize = 0;
if ((oob=doubledl(&csrc, &mydl, source, ssize))) {
if (oob == -1)
return -1;
/* 16a */
backbytes = 0;
if ((oob=doubledl(&csrc, &mydl, source, ssize))) {
if (oob == -1)
return -1;
/* 170 */
lostbit = 1;
backsize++;
backbytes = 0x10;
while ( backbytes < 0x100 ) {
if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
return -1;
backbytes = backbytes*2+oob;
}
backbytes &= 0xff;
if ( ! backbytes ) {
if (cdst >= dest+dsize)
return -1;
*cdst++=0x00;
continue;
}
} else {
/* 18f */
if (csrc >= source+ssize)
return -1;
backbytes = *(unsigned char*)csrc;
backsize = backsize * 2 + (backbytes & 1);
backbytes = (backbytes & 0xff)>>1;
csrc++;
if (! backbytes)
break;
backsize+=2;
oldback = backbytes;
lostbit = 0;
}
} else {
/* 180 */
backsize = 1;
do {
if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
return -1;
backsize = backsize*2+oob;
if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
return -1;
} while (oob);
backsize = backsize - 1 - lostbit;
if (! backsize) {
/* 18a */
backsize = 1;
do {
if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
return -1;
backsize = backsize*2+oob;
if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
return -1;
} while (oob);
backbytes = oldback;
} else {
/* 198 */
if (csrc >= source+ssize)
return -1;
backbytes = *(unsigned char*)csrc;
backbytes += (backsize-1)<<8;
backsize = 1;
csrc++;
do {
if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
return -1;
backsize = backsize*2+oob;
if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
return -1;
} while (oob);
if (backbytes >= 0x7d00)
backsize++;
if (backbytes >= 0x500)
backsize++;
if (backbytes <= 0x7f)
backsize += 2;
oldback = backbytes;
}
lostbit = 0;
}
if (!CLI_ISCONTAINED(dest, dsize, cdst, backsize) || !CLI_ISCONTAINED(dest, dsize, cdst-backbytes, backsize))
return -1;
while(backsize--) {
*cdst=*(cdst-backbytes);
cdst++;
}
} else {
/* 15d */
if (cdst < dest || cdst >= dest+dsize || csrc < source || csrc >= source+ssize)
return -1;
*cdst++=*csrc++;
lostbit=1;
}
}
if (endsrc) *endsrc = csrc;
if (enddst) *enddst = cdst;
return 0;
} |