186 lines
4.8 KiB
C
186 lines
4.8 KiB
C
/*
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* Copyright (C) 2013-2022 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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* Copyright (C) 2007-2013 Sourcefire, Inc.
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*
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* Authors: Tomasz Kojm
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*
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* Acknowledgements: Decompression scheme by M. Winterhoff.
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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 <stdio.h>
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#include <stddef.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <string.h>
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#include "clamav.h"
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#include "others.h"
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#include "msexpand.h"
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#include "fmap.h"
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#ifndef HAVE_ATTRIB_PACKED
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#define __attribute__(x)
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#endif
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#ifdef HAVE_PRAGMA_PACK
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#pragma pack(1)
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#endif
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#ifdef HAVE_PRAGMA_PACK_HPPA
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#pragma pack 1
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#endif
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#define EC32(x) le32_to_host(x)
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#define EC16(x) le16_to_host(x)
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#define MAGIC1 0x44445a53
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#define MAGIC2 0x3327f088
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#define MAGIC3 0x0041
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struct msexp_hdr {
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uint32_t magic1;
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uint32_t magic2;
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uint16_t magic3;
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uint32_t fsize;
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} __attribute__((packed));
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#ifdef HAVE_PRAGMA_PACK
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#pragma pack()
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#endif
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#ifdef HAVE_PRAGMA_PACK_HPPA
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#pragma pack
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#endif
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#define B_SIZE 4096
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#define RW_SIZE 2048
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#define READBYTES \
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rbytes = MIN(RW_SIZE, map->len - cur_off); \
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if (!rbytes) \
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break; \
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rbuff = fmap_need_off_once(map, cur_off, rbytes); \
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if (!rbuff) \
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return CL_EREAD; \
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cur_off += rbytes; \
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r = 0;
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#define WRITEBYTES \
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ret = cli_writen(ofd, wbuff, w); \
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if (ret == (size_t)-1 || (unsigned int)ret != w) \
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return CL_EWRITE; \
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wbytes += w; \
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if (wbytes >= fsize) \
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return CL_SUCCESS; \
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w = 0;
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cl_error_t cli_msexpand(cli_ctx *ctx, int ofd)
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{
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const struct msexp_hdr *hdr;
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uint8_t i, mask, bits;
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unsigned char buff[B_SIZE], wbuff[RW_SIZE];
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const unsigned char *rbuff = NULL; // rbuff will be set to a real address by READBYTES
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// in the first iteration of the loop.
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unsigned int j = B_SIZE - 16, k, l, r = 0, w = 0, rbytes = 0, wbytes = 0;
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fmap_t *map = ctx->fmap;
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off_t cur_off = sizeof(*hdr);
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unsigned int fsize;
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size_t ret;
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if (!(hdr = fmap_need_off_once(map, 0, sizeof(*hdr))))
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return CL_EREAD;
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if (EC32(hdr->magic1) != MAGIC1 || EC32(hdr->magic2) != MAGIC2 || EC16(hdr->magic3) != MAGIC3) {
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cli_dbgmsg("MSEXPAND: Not supported file format\n");
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return CL_EFORMAT;
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}
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fsize = EC32(hdr->fsize);
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cli_dbgmsg("MSEXPAND: File size from header: %u\n", fsize);
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if (cli_checklimits("MSEXPAND", ctx, fsize, 0, 0) != CL_CLEAN)
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return CL_SUCCESS;
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memset(buff, 0, B_SIZE);
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while (1) {
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if (!rbytes || (r == rbytes)) {
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READBYTES;
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}
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bits = rbuff[r];
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r++;
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mask = 1;
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for (i = 0; i < 8; i++) {
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if (bits & mask) {
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if (r == rbytes) {
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READBYTES;
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}
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if (w == RW_SIZE) {
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WRITEBYTES;
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}
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wbuff[w] = buff[j] = rbuff[r];
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r++;
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w++;
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j++;
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j %= B_SIZE;
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} else {
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if (r == rbytes) {
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READBYTES;
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}
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k = rbuff[r];
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r++;
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if (r == rbytes) {
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READBYTES;
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}
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l = rbuff[r];
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r++;
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k += (l & 0xf0) << 4;
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l = (l & 0x0f) + 3;
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while (l--) {
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if (w == RW_SIZE) {
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WRITEBYTES;
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}
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wbuff[w] = buff[j] = buff[k];
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w++;
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k++;
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k %= B_SIZE;
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j++;
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j %= B_SIZE;
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}
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}
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mask *= 2;
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}
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}
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if (w) {
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WRITEBYTES;
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}
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return CL_SUCCESS;
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}
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