denyhosts/clamscan/libclamav/fsg.c

/*
 *  Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 *  Copyright (C) 2007-2013 Sourcefire, Inc.
 *
 *  Authors: Alberto Wu
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  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.
 */

/*
** defsg.c
**
** 02/08/2k4 - Dumped and reversed
** 02/08/2k4 - Done coding
** 03/08/2k4 - Cleaning and securing
** 04/08/2k4 - Done porting
** 07/08/2k4 - Started adding support for 1.33
*/

/*
** Unpacks an FSG compressed section.
**
** Czesc bart, good asm, nice piece of code ;)
*/

#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif

#include <stdlib.h>

#include "clamav.h"
#include "rebuildpe.h"
#include "others.h"
#include "packlibs.h"
#include "fsg.h"

int unfsg_200(const char *source, char *dest, int ssize, int dsize, uint32_t rva, uint32_t base, uint32_t ep, int file)
{
    struct cli_exe_section section; /* Yup, just one ;) */

    if (cli_unfsg(source, dest, ssize, dsize, NULL, NULL)) return -1;

    section.raw = 0;
    section.rsz = dsize;
    section.vsz = dsize;
    section.rva = rva;

    if (!cli_rebuildpe(dest, &section, 1, base, ep, 0, 0, file)) {
        cli_dbgmsg("FSG: Rebuilding failed\n");
        return 0;
    }
    return 1;
}

int unfsg_133(const char *source, char *dest, int ssize, int dsize, struct cli_exe_section *sections, int sectcount, uint32_t base, uint32_t ep, int file)
{
    const char *tsrc = source;
    char *tdst       = dest;
    int i, upd = 1, offs = 0, lastsz = dsize;

    for (i = 0; i <= sectcount; i++) {
        char *startd = tdst;
        if (cli_unfsg(tsrc, tdst, ssize - (tsrc - source), dsize - (tdst - dest), &tsrc, &tdst) == -1)
            return -1;

        /* RVA has been filled already in pe.c */
        sections[i].raw = offs;
        sections[i].rsz = tdst - startd;
        /*    cli_dbgmsg("Unpacked section %d @%x size %x Vsize =%x \n", i, offs, tdst-startd, dsize - (startd - dest)); */
        offs += tdst - startd;
    }

    /* Sort out the sections */
    while (upd) {
        upd = 0;
        for (i = 0; i < sectcount; i++) {
            uint32_t trva, trsz, traw;

            if (sections[i].rva <= sections[i + 1].rva)
                continue;
            trva                = sections[i].rva;
            traw                = sections[i].raw;
            trsz                = sections[i].rsz;
            sections[i].rva     = sections[i + 1].rva;
            sections[i].rsz     = sections[i + 1].rsz;
            sections[i].raw     = sections[i + 1].raw;
            sections[i + 1].rva = trva;
            sections[i + 1].raw = traw;
            sections[i + 1].rsz = trsz;
            upd                 = 1;
        }
    }

    /* Cure Vsizes and debugspam */
    for (i = 0; i <= sectcount; i++) {
        if (i != sectcount) {
            sections[i].vsz = sections[i + 1].rva - sections[i].rva;
            lastsz -= sections[i + 1].rva - sections[i].rva;
        } else
            sections[i].vsz = lastsz;

        cli_dbgmsg("FSG: .SECT%d RVA:%x VSize:%x ROffset: %x, RSize:%x\n", i, sections[i].rva, sections[i].vsz, sections[i].raw, sections[i].rsz);
    }

    if (!cli_rebuildpe(dest, sections, sectcount + 1, base, ep, 0, 0, file)) {
        cli_dbgmsg("FSG: Rebuilding failed\n");
        return 0;
    }
    return 1;
}