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312 lines
7.7 KiB
312 lines
7.7 KiB
/*
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* Copyright (C) 2007-2008 Sourcefire, Inc.
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*
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* Authors: Alberto Wu, Michal 'GiM' Spadlinski
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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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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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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#if HAVE_CONFIG_H
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#include "clamav-config.h"
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#endif
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#include "others.h"
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#include "execs.h"
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#include "pe.h"
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#include "packlibs.h"
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static int doubledl(const char **scur, uint8_t *mydlptr, const char *buffer, uint32_t buffersize)
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{
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unsigned char mydl = *mydlptr;
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unsigned char olddl = mydl;
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mydl*=2;
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if ( !(olddl & 0x7f)) {
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if ( *scur < buffer || *scur >= buffer+buffersize-1 )
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return -1;
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olddl = **scur;
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mydl = olddl*2+1;
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*scur=*scur + 1;
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}
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*mydlptr = mydl;
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return (olddl>>7)&1;
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}
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int cli_unfsg(const char *source, char *dest, int ssize, int dsize, const char **endsrc, char **enddst) {
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uint8_t mydl=0x80;
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uint32_t backbytes, backsize, oldback = 0;
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const char *csrc = source;
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char *cdst = dest;
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int oob, lostbit = 1;
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if (ssize<=0 || dsize<=0) return -1;
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*cdst++=*csrc++;
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while ( 1 ) {
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if ((oob=doubledl(&csrc, &mydl, source, ssize))) {
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if (oob == -1)
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return -1;
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/* 164 */
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backsize = 0;
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if ((oob=doubledl(&csrc, &mydl, source, ssize))) {
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if (oob == -1)
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return -1;
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/* 16a */
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backbytes = 0;
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if ((oob=doubledl(&csrc, &mydl, source, ssize))) {
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if (oob == -1)
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return -1;
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/* 170 */
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lostbit = 1;
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backsize++;
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backbytes = 0x10;
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while ( backbytes < 0x100 ) {
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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backbytes = backbytes*2+oob;
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}
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backbytes &= 0xff;
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if ( ! backbytes ) {
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if (cdst >= dest+dsize)
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return -1;
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*cdst++=0x00;
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continue;
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}
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} else {
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/* 18f */
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if (csrc >= source+ssize)
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return -1;
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backbytes = *(unsigned char*)csrc;
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backsize = backsize * 2 + (backbytes & 1);
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backbytes = (backbytes & 0xff)>>1;
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csrc++;
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if (! backbytes)
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break;
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backsize+=2;
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oldback = backbytes;
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lostbit = 0;
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}
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} else {
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/* 180 */
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backsize = 1;
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do {
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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backsize = backsize*2+oob;
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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} while (oob);
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backsize = backsize - 1 - lostbit;
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if (! backsize) {
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/* 18a */
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backsize = 1;
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do {
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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backsize = backsize*2+oob;
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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} while (oob);
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backbytes = oldback;
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} else {
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/* 198 */
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if (csrc >= source+ssize)
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return -1;
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backbytes = *(unsigned char*)csrc;
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backbytes += (backsize-1)<<8;
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backsize = 1;
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csrc++;
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do {
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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backsize = backsize*2+oob;
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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} while (oob);
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if (backbytes >= 0x7d00)
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backsize++;
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if (backbytes >= 0x500)
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backsize++;
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if (backbytes <= 0x7f)
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backsize += 2;
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oldback = backbytes;
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}
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lostbit = 0;
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}
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if (!CLI_ISCONTAINED(dest, dsize, cdst, backsize) || !CLI_ISCONTAINED(dest, dsize, cdst-backbytes, backsize))
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return -1;
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while(backsize--) {
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*cdst=*(cdst-backbytes);
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cdst++;
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}
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} else {
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/* 15d */
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if (cdst < dest || cdst >= dest+dsize || csrc < source || csrc >= source+ssize)
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return -1;
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*cdst++=*csrc++;
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lostbit=1;
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}
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}
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if (endsrc) *endsrc = csrc;
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if (enddst) *enddst = cdst;
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return 0;
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}
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int unmew(const char *source, char *dest, int ssize, int dsize, const char **endsrc, char **enddst) {
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uint8_t mydl=0x80;
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uint32_t myeax_backbytes, myecx_backsize, oldback = 0;
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const char *csrc = source;
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char *cdst = dest;
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int oob, lostbit = 1;
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*cdst++=*csrc++;
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while ( 1 ) {
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if ((oob=doubledl(&csrc, &mydl, source, ssize))) {
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if (oob == -1)
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return -1;
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/* 164 */
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myecx_backsize = 0;
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if ((oob=doubledl(&csrc, &mydl, source, ssize))) {
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if (oob == -1)
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return -1;
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/* 16a */
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myeax_backbytes = 0;
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if ((oob=doubledl(&csrc, &mydl, source, ssize))) {
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if (oob == -1)
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return -1;
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/* 170 */
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lostbit = 1;
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myecx_backsize++;
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myeax_backbytes = 0x10;
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while ( myeax_backbytes < 0x100 ) {
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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myeax_backbytes = myeax_backbytes*2+oob;
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}
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myeax_backbytes &= 0xff;
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if ( ! myeax_backbytes ) {
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if (cdst >= dest+dsize)
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return -1;
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*cdst++=0x00;
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/*cli_dbgmsg("X%02x ", *(cdst-1)&0xff);*/
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continue;
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}
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} else {
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/* 18f */
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if (csrc >= source+ssize)
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return -1;
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myeax_backbytes = *(unsigned char*)csrc;
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myecx_backsize = myecx_backsize * 2 + (myeax_backbytes & 1);
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myeax_backbytes = (myeax_backbytes & 0xff)>>1;
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csrc++;
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if (! myeax_backbytes)
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{
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/* cli_dbgmsg("\nBREAK \n"); */
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break;
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}
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myecx_backsize+=2;
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oldback = myeax_backbytes;
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lostbit = 0;
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}
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} else {
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/* 180 */
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myecx_backsize = 1;
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do {
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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myecx_backsize = myecx_backsize*2+oob;
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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} while (oob);
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myecx_backsize = myecx_backsize - 1 - lostbit;
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if (! myecx_backsize) {
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/* 18a */
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myecx_backsize = 1;
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do {
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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myecx_backsize = myecx_backsize*2+oob;
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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} while (oob);
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myeax_backbytes = oldback;
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} else {
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/* 198 */
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if (csrc >= source+ssize)
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return -1;
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myeax_backbytes = *(unsigned char*)csrc;
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myeax_backbytes += (myecx_backsize-1)<<8;
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myecx_backsize = 1;
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csrc++;
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do {
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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myecx_backsize = myecx_backsize*2+oob;
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if ((oob=doubledl(&csrc, &mydl, source, ssize)) == -1)
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return -1;
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} while (oob);
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if (myeax_backbytes >= 0x7d00)
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myecx_backsize++;
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if (myeax_backbytes >= 0x500)
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myecx_backsize++;
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if (myeax_backbytes <= 0x7f)
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myecx_backsize += 2;
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oldback = myeax_backbytes;
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}
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lostbit = 0;
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}
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if (!CLI_ISCONTAINED(dest, dsize, cdst, myecx_backsize) || !CLI_ISCONTAINED(dest, dsize, cdst-myeax_backbytes, myecx_backsize))
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{
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cli_dbgmsg("MEW: rete: %p %d %p %d %d || %p %d %p %d %d\n", dest, dsize, cdst, myecx_backsize,
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CLI_ISCONTAINED(dest, dsize, cdst, myecx_backsize),
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dest, dsize, cdst-myeax_backbytes, myecx_backsize,
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CLI_ISCONTAINED(dest, dsize, cdst-myeax_backbytes, myecx_backsize) );
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return -1;
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}
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while(myecx_backsize--) {
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*cdst=*(cdst-myeax_backbytes);
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cdst++;
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}
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} else {
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/* 15d */
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if (cdst < dest || cdst >= dest+dsize || csrc < source || csrc >= source+ssize)
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{
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cli_dbgmsg("MEW: retf %p %p+%08x=%p, %p %p+%08x=%p\n",
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cdst, dest, dsize, dest+dsize, csrc, source, ssize, source+ssize);
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return -1;
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}
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*cdst++=*csrc++;
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/* cli_dbgmsg("Z%02x ", *(cdst-1)&0xff); */
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lostbit=1;
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}
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}
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*endsrc = csrc;
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*enddst = cdst;
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return 0;
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}
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