/*
* Copyright (C) 2013-2019 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.
*/
/* FIXME: get a clue about masked stuff */
#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include <zlib.h>
#include "inflate64.h"
#if HAVE_BZLIB_H
#include <bzlib.h>
#endif
#include "explode.h"
#include "others.h"
#include "clamav.h"
#include "scanners.h"
#include "matcher.h"
#include "fmap.h"
#include "json_api.h"
#define UNZIP_PRIVATE
#include "unzip.h"
#define ZIP_MAX_NUM_OVERLAPPING_FILES 5
#define ZIP_CRC32(r, c, b, l) \
do { \
r = crc32(~c, b, l); \
r = ~r; \
} while (0)
static int wrap_inflateinit2(void *a, int b)
{
return inflateInit2(a, b);
}
static int unz(const uint8_t *src, uint32_t csize, uint32_t usize, uint16_t method, uint16_t flags, unsigned int *fu, cli_ctx *ctx, char *tmpd, zip_cb zcb)
{
char name[1024], obuf[BUFSIZ];
char *tempfile = name;
int of, ret = CL_CLEAN;
unsigned int res = 1, written = 0;
if (tmpd) {
snprintf(name, sizeof(name), "%s" PATHSEP "zip.%03u", tmpd, *fu);
name[sizeof(name) - 1] = '\0';
} else {
if (!(tempfile = cli_gentemp(ctx->engine->tmpdir))) return CL_EMEM;
}
if ((of = open(tempfile, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR | S_IWUSR)) == -1) {
cli_warnmsg("cli_unzip: failed to create temporary file %s\n", tempfile);
if (!tmpd) free(tempfile);
return CL_ETMPFILE;
}
switch (method) {
case ALG_STORED:
if (csize < usize) {
unsigned int fake = *fu + 1;
cli_dbgmsg("cli_unzip: attempting to inflate stored file with inconsistent size\n");
if ((ret = unz(src, csize, usize, ALG_DEFLATE, 0, &fake, ctx, tmpd, zcb)) == CL_CLEAN) {
(*fu)++;
res = fake - (*fu);
} else
break;
}
if (res == 1) {
if (ctx->engine->maxfilesize && csize > ctx->engine->maxfilesize) {
cli_dbgmsg("cli_unzip: trimming output size to maxfilesize (%lu)\n", (long unsigned int)ctx->engine->maxfilesize);
csize = ctx->engine->maxfilesize;
}
if (cli_writen(of, src, csize) != (int)csize)
ret = CL_EWRITE;
else
res = 0;
}
break;
case ALG_DEFLATE:
case ALG_DEFLATE64: {
union {
z_stream64 strm64;
z_stream strm;
} strm;
typedef int (*unz_init_)(void *, int);
typedef int (*unz_unz_)(void *, int);
typedef int (*unz_end_)(void *);
unz_init_ unz_init;
unz_unz_ unz_unz;
unz_end_ unz_end;
int wbits;
void **next_in;
void **next_out;
unsigned int *avail_in;
unsigned int *avail_out;
if (method == ALG_DEFLATE64) {
unz_init = (unz_init_)inflate64Init2;
unz_unz = (unz_unz_)inflate64;
unz_end = (unz_end_)inflate64End;
next_in = (void *)&strm.strm64.next_in;
next_out = (void *)&strm.strm64.next_out;
avail_in = &strm.strm64.avail_in;
avail_out = &strm.strm64.avail_out;
wbits = MAX_WBITS64;
} else {
unz_init = (unz_init_)wrap_inflateinit2;
unz_unz = (unz_unz_)inflate;
unz_end = (unz_end_)inflateEnd;
next_in = (void *)&strm.strm.next_in;
next_out = (void *)&strm.strm.next_out;
avail_in = &strm.strm.avail_in;
avail_out = &strm.strm.avail_out;
wbits = MAX_WBITS;
}
memset(&strm, 0, sizeof(strm));
*next_in = (void *)src;
*next_out = obuf;
*avail_in = csize;
*avail_out = sizeof(obuf);
if (unz_init(&strm, -wbits) != Z_OK) {
cli_dbgmsg("cli_unzip: zinit failed\n");
break;
}
while (1) {
while ((res = unz_unz(&strm, Z_NO_FLUSH)) == Z_OK) {
};
if (*avail_out != sizeof(obuf)) {
written += sizeof(obuf) - (*avail_out);
if (ctx->engine->maxfilesize && written > ctx->engine->maxfilesize) {
cli_dbgmsg("cli_unzip: trimming output size to maxfilesize (%lu)\n", (long unsigned int)ctx->engine->maxfilesize);
res = Z_STREAM_END;
break;
}
if (cli_writen(of, obuf, sizeof(obuf) - (*avail_out)) != (int)(sizeof(obuf) - (*avail_out))) {
cli_warnmsg("cli_unzip: falied to write %lu inflated bytes\n", (unsigned long int)sizeof(obuf) - (*avail_out));
ret = CL_EWRITE;
res = 100;
break;
}
*next_out = obuf;
*avail_out = sizeof(obuf);
continue;
}
break;
}
unz_end(&strm);
if ((res == Z_STREAM_END) | (res == Z_BUF_ERROR)) res = 0;
break;
}
#if HAVE_BZLIB_H
#ifdef NOBZ2PREFIX
#define BZ2_bzDecompress bzDecompress
#define BZ2_bzDecompressEnd bzDecompressEnd
#define BZ2_bzDecompressInit bzDecompressInit
#endif
case ALG_BZIP2: {
bz_stream strm;
memset(&strm, 0, sizeof(strm));
strm.next_in = (char *)src;
strm.next_out = obuf;
strm.avail_in = csize;
strm.avail_out = sizeof(obuf);
if (BZ2_bzDecompressInit(&strm, 0, 0) != BZ_OK) {
cli_dbgmsg("cli_unzip: bzinit failed\n");
break;
}
while ((res = BZ2_bzDecompress(&strm)) == BZ_OK || res == BZ_STREAM_END) {
if (strm.avail_out != sizeof(obuf)) {
written += sizeof(obuf) - strm.avail_out;
if (ctx->engine->maxfilesize && written > ctx->engine->maxfilesize) {
cli_dbgmsg("cli_unzip: trimming output size to maxfilesize (%lu)\n", (unsigned long int)ctx->engine->maxfilesize);
res = BZ_STREAM_END;
break;
}
if (cli_writen(of, obuf, sizeof(obuf) - strm.avail_out) != (int)(sizeof(obuf) - strm.avail_out)) {
cli_warnmsg("cli_unzip: falied to write %lu bunzipped bytes\n", (long unsigned int)sizeof(obuf) - strm.avail_out);
ret = CL_EWRITE;
res = 100;
break;
}
strm.next_out = obuf;
strm.avail_out = sizeof(obuf);
if (res == BZ_OK) continue; /* after returning BZ_STREAM_END once, decompress returns an error */
}
break;
}
BZ2_bzDecompressEnd(&strm);
if (res == BZ_STREAM_END) res = 0;
break;
}
#endif /* HAVE_BZLIB_H */
case ALG_IMPLODE: {
struct xplstate strm;
strm.next_in = (void *)src;
strm.next_out = (uint8_t *)obuf;
strm.avail_in = csize;
strm.avail_out = sizeof(obuf);
if (explode_init(&strm, flags) != EXPLODE_OK) {
cli_dbgmsg("cli_unzip: explode_init() failed\n");
break;
}
while ((res = explode(&strm)) == EXPLODE_OK) {
if (strm.avail_out != sizeof(obuf)) {
written += sizeof(obuf) - strm.avail_out;
if (ctx->engine->maxfilesize && written > ctx->engine->maxfilesize) {
cli_dbgmsg("cli_unzip: trimming output size to maxfilesize (%lu)\n", (unsigned long int)ctx->engine->maxfilesize);
res = 0;
break;
}
if (cli_writen(of, obuf, sizeof(obuf) - strm.avail_out) != (int)(sizeof(obuf) - strm.avail_out)) {
cli_warnmsg("cli_unzip: falied to write %lu exploded bytes\n", (unsigned long int)sizeof(obuf) - strm.avail_out);
ret = CL_EWRITE;
res = 100;
break;
}
strm.next_out = (uint8_t *)obuf;
strm.avail_out = sizeof(obuf);
continue;
}
break;
}
break;
}
case ALG_LZMA:
/* easy but there's not a single sample in the zoo */
#if !HAVE_BZLIB_H
case ALG_BZIP2:
#endif
case ALG_SHRUNK:
case ALG_REDUCE1:
case ALG_REDUCE2:
case ALG_REDUCE3:
case ALG_REDUCE4:
case ALG_TOKENZD:
case ALG_OLDTERSE:
case ALG_RSVD1:
case ALG_RSVD2:
case ALG_RSVD3:
case ALG_RSVD4:
case ALG_RSVD5:
case ALG_NEWTERSE:
case ALG_LZ77:
case ALG_WAVPACK:
case ALG_PPMD:
cli_dbgmsg("cli_unzip: unsupported method (%d)\n", method);
break;
default:
cli_dbgmsg("cli_unzip: unknown method (%d)\n", method);
break;
}
if (!res) {
(*fu)++;
cli_dbgmsg("cli_unzip: extracted to %s\n", tempfile);
if (lseek(of, 0, SEEK_SET) == -1) {
cli_dbgmsg("cli_unzip: call to lseek() failed\n");
if (!(tmpd))
free(tempfile);
close(of);
return CL_ESEEK;
}
ret = zcb(of, tempfile, ctx);
close(of);
if (!ctx->engine->keeptmp)
if (cli_unlink(tempfile)) ret = CL_EUNLINK;
if (!tmpd) free(tempfile);
return ret;
}
close(of);
if (!ctx->engine->keeptmp)
if (cli_unlink(tempfile)) ret = CL_EUNLINK;
if (!tmpd) free(tempfile);
cli_dbgmsg("cli_unzip: extraction failed\n");
return ret;
}
/* zip update keys, taken from zip specification */
static inline void zupdatekey(uint32_t key[3], unsigned char input)
{
unsigned char tmp[1];
unsigned long crctmp;
tmp[0] = input;
ZIP_CRC32(key[0], key[0], tmp, 1);
key[1] = key[1] + (key[0] & 0xff);
key[1] = key[1] * 134775813 + 1;
tmp[0] = key[1] >> 24;
ZIP_CRC32(key[2], key[2], tmp, 1);
}
/* zip init keys */
static inline void zinitkey(uint32_t key[3], struct cli_pwdb *password)
{
int i;
/* initialize keys, these are specified but the zip specification */
key[0] = 305419896L;
key[1] = 591751049L;
key[2] = 878082192L;
/* update keys with password */
for (i = 0; i < password->length; i++)
zupdatekey(key, password->passwd[i]);
}
/* zip decrypt byte */
static inline unsigned char zdecryptbyte(uint32_t key[3])
{
unsigned short temp;
temp = key[2] | 2;
return ((temp * (temp ^ 1)) >> 8);
}
/* zip decrypt, CL_EPARSE = could not apply a password, csize includes the decryption header */
/* TODO - search for strong encryption header (0x0017) and handle them */
static inline int zdecrypt(const uint8_t *src, uint32_t csize, uint32_t usize, const uint8_t *lh, unsigned int *fu, cli_ctx *ctx, char *tmpd, zip_cb zcb)
{
int i, ret, v = 0;
uint32_t key[3];
uint8_t eh[12]; /* encryption header buffer */
struct cli_pwdb *password, *pass_any, *pass_zip;
if (!ctx || !ctx->engine)
return CL_ENULLARG;
/* dconf */
if (ctx->dconf && !(ctx->dconf->archive & ARCH_CONF_PASSWD)) {
cli_dbgmsg("cli_unzip: decrypt - skipping encrypted file\n");
return CL_SUCCESS;
}
pass_any = ctx->engine->pwdbs[CLI_PWDB_ANY];
pass_zip = ctx->engine->pwdbs[CLI_PWDB_ZIP];
while (pass_any || pass_zip) {
password = pass_zip ? pass_zip : pass_any;
zinitkey(key, password);
/* decrypting the encryption header */
memcpy(eh, src, SIZEOF_EH);
for (i = 0; i < SIZEOF_EH; i++) {
eh[i] ^= zdecryptbyte(key);
zupdatekey(key, eh[i]);
}
/* verify that the password is correct */
if (LH_version > 20) { /* higher than 2.0 */
uint16_t a = eh[SIZEOF_EH - 1];
if (LH_flags & F_USEDD) {
cli_dbgmsg("cli_unzip: decrypt - (v%u) >> 0x%02x 0x%x (moddate)\n", LH_version, a, LH_mtime);
if (a == ((LH_mtime >> 8) & 0xff))
v = 1;
} else {
cli_dbgmsg("cli_unzip: decrypt - (v%u) >> 0x%02x 0x%x (crc32)\n", LH_version, a, LH_crc32);
if (a == ((LH_crc32 >> 24) & 0xff))
v = 1;
}
} else {
uint16_t a = eh[SIZEOF_EH - 1], b = eh[SIZEOF_EH - 2];
if (LH_flags & F_USEDD) {
cli_dbgmsg("cli_unzip: decrypt - (v%u) >> 0x0000%02x%02x 0x%x (moddate)\n", LH_version, a, b, LH_mtime);
if ((b | (a << 8)) == (LH_mtime & 0xffff))
v = 1;
} else {
cli_dbgmsg("cli_unzip: decrypt - (v%u) >> 0x0000%02x%02x 0x%x (crc32)\n", LH_version, eh[SIZEOF_EH - 1], eh[SIZEOF_EH - 2], LH_crc32);
if ((b | (a << 8)) == ((LH_crc32 >> 16) & 0xffff))
v = 1;
}
}
if (v) {
char name[1024], obuf[BUFSIZ];
char *tempfile = name;
unsigned int written = 0, total = 0;
fmap_t *dcypt_map;
const uint8_t *dcypt_zip;
int of;
cli_dbgmsg("cli_unzip: decrypt - password [%s] matches\n", password->name);
/* output decrypted data to tempfile */
if (tmpd) {
snprintf(name, sizeof(name), "%s" PATHSEP "zip.decrypt.%03u", tmpd, *fu);
name[sizeof(name) - 1] = '\0';
} else {
if (!(tempfile = cli_gentemp(ctx->engine->tmpdir))) return CL_EMEM;
}
if ((of = open(tempfile, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, S_IRUSR | S_IWUSR)) == -1) {
cli_warnmsg("cli_unzip: decrypt - failed to create temporary file %s\n", tempfile);
if (!tmpd) free(tempfile);
return CL_ETMPFILE;
}
for (i = 12; i < csize; i++) {
obuf[written] = src[i] ^ zdecryptbyte(key);
zupdatekey(key, obuf[written]);
written++;
if (written >= BUFSIZ) {
if (cli_writen(of, obuf, written) != (int)written) {
ret = CL_EWRITE;
goto zd_clean;
}
total += written;
written = 0;
}
}
if (written) {
if (cli_writen(of, obuf, written) != (int)written) {
ret = CL_EWRITE;
goto zd_clean;
}
total += written;
written = 0;
}
cli_dbgmsg("cli_unzip: decrypt - decrypted %u bytes to %s\n", total, tempfile);
/* decrypt data to new fmap -> buffer */
if (!(dcypt_map = fmap(of, 0, total))) {
cli_warnmsg("cli_unzip: decrypt - failed to create fmap on decrypted file %s\n", tempfile);
ret = CL_EMAP;
goto zd_clean;
}
if (!(dcypt_zip = fmap_need_off_once(dcypt_map, 0, total))) {
cli_warnmsg("cli_unzip: decrypt - failed to acquire buffer on decrypted file %s\n", tempfile);
funmap(dcypt_map);
ret = CL_EREAD;
goto zd_clean;
}
/* call unz on decrypted output */
ret = unz(dcypt_zip, csize - SIZEOF_EH, usize, LH_method, LH_flags, fu, ctx, tmpd, zcb);
/* clean-up and return */
funmap(dcypt_map);
zd_clean:
close(of);
if (!ctx->engine->keeptmp)
if (cli_unlink(tempfile)) {
if (!tmpd) free(tempfile);
return CL_EUNLINK;
}
if (!tmpd) free(tempfile);
return ret;
}
if (pass_zip)
pass_zip = pass_zip->next;
else
pass_any = pass_any->next;
}
cli_dbgmsg("cli_unzip: decrypt - skipping encrypted file, no valid passwords\n");
return CL_SUCCESS;
}
static unsigned int lhdr(fmap_t *map, uint32_t loff, uint32_t zsize, unsigned int *fu, unsigned int fc, const uint8_t *ch, int *ret, cli_ctx *ctx, char *tmpd, int detect_encrypted, zip_cb zcb, uint32_t *file_local_header_size, uint32_t *file_local_data_size)
{
const uint8_t *lh, *zip;
char name[256];
uint32_t csize, usize;
int virus_found = 0;
if (!(lh = fmap_need_off(map, loff, SIZEOF_LH))) {
cli_dbgmsg("cli_unzip: lh - out of file\n");
return 0;
}
if (LH_magic != 0x04034b50) {
if (!ch)
cli_dbgmsg("cli_unzip: lh - wrkcomplete\n");
else
cli_dbgmsg("cli_unzip: lh - bad magic\n");
fmap_unneed_off(map, loff, SIZEOF_LH);
return 0;
}
zip = lh + SIZEOF_LH;
zsize -= SIZEOF_LH;
if (zsize <= LH_flen) {
cli_dbgmsg("cli_unzip: lh - fname out of file\n");
fmap_unneed_off(map, loff, SIZEOF_LH);
return 0;
}
if (ctx->engine->cdb || cli_debug_flag) {
uint32_t nsize = (LH_flen >= sizeof(name)) ? sizeof(name) - 1 : LH_flen;
const char *src;
if (nsize && (src = fmap_need_ptr_once(map, zip, nsize))) {
memcpy(name, zip, nsize);
name[nsize] = '\0';
} else
name[0] = '\0';
}
zip += LH_flen;
zsize -= LH_flen;
cli_dbgmsg("cli_unzip: lh - ZMDNAME:%d:%s:%u:%u:%x:%u:%u:%u\n", ((LH_flags & F_ENCR) != 0), name, LH_usize, LH_csize, LH_crc32, LH_method, fc, ctx->recursion);
/* ZMDfmt virname:encrypted(0-1):filename(exact|*):usize(exact|*):csize(exact|*):crc32(exact|*):method(exact|*):fileno(exact|*):maxdepth(exact|*) */
if (cli_matchmeta(ctx, name, LH_csize, LH_usize, (LH_flags & F_ENCR) != 0, fc, LH_crc32, NULL) == CL_VIRUS) {
*ret = CL_VIRUS;
if (!SCAN_ALLMATCHES)
return 0;
virus_found = 1;
}
if (LH_flags & F_MSKED) {
cli_dbgmsg("cli_unzip: lh - header has got unusable masked data\n");
/* FIXME: need to find/craft a sample */
fmap_unneed_off(map, loff, SIZEOF_LH);
return 0;
}
if (detect_encrypted && (LH_flags & F_ENCR) && SCAN_HEURISTIC_ENCRYPTED_ARCHIVE) {
cli_dbgmsg("cli_unzip: Encrypted files found in archive.\n");
*ret = cli_append_virus(ctx, "Heuristics.Encrypted.Zip");
if ((*ret == CL_VIRUS && !SCAN_ALLMATCHES) || *ret != CL_CLEAN) {
fmap_unneed_off(map, loff, SIZEOF_LH);
return 0;
}
virus_found = 1;
}
if (LH_flags & F_USEDD) {
cli_dbgmsg("cli_unzip: lh - has data desc\n");
if (!ch) {
fmap_unneed_off(map, loff, SIZEOF_LH);
return 0;
} else {
usize = CH_usize;
csize = CH_csize;
}
} else {
usize = LH_usize;
csize = LH_csize;
}
if (zsize <= LH_elen) {
cli_dbgmsg("cli_unzip: lh - extra out of file\n");
fmap_unneed_off(map, loff, SIZEOF_LH);
return 0;
}
zip += LH_elen;
zsize -= LH_elen;
if (NULL != file_local_header_size)
*file_local_header_size = zip - lh;
if (NULL != file_local_data_size)
*file_local_data_size = csize;
if (!csize) { /* FIXME: what's used for method0 files? csize or usize? Nothing in the specs, needs testing */
cli_dbgmsg("cli_unzip: lh - skipping empty file\n");
} else {
if (zsize < csize) {
cli_dbgmsg("cli_unzip: lh - stream out of file\n");
fmap_unneed_off(map, loff, SIZEOF_LH);
return 0;
}
if (LH_flags & F_ENCR) {
if (fmap_need_ptr_once(map, zip, csize))
*ret = zdecrypt(zip, csize, usize, lh, fu, ctx, tmpd, zcb);
} else {
if (fmap_need_ptr_once(map, zip, csize))
*ret = unz(zip, csize, usize, LH_method, LH_flags, fu, ctx, tmpd, zcb);
}
zip += csize;
zsize -= csize;
}
if (virus_found != 0)
*ret = CL_VIRUS;
fmap_unneed_off(map, loff, SIZEOF_LH); /* unneed now. block is guaranteed to exists till the next need */
if (LH_flags & F_USEDD) {
if (zsize < 12) {
cli_dbgmsg("cli_unzip: lh - data desc out of file\n");
return 0;
}
zsize -= 12;
if (fmap_need_ptr_once(map, zip, 4)) {
if (cli_readint32(zip) == 0x08074b50) {
if (zsize < 4) {
cli_dbgmsg("cli_unzip: lh - data desc out of file\n");
return 0;
}
zip += 4;
}
}
zip += 12;
}
return zip - lh;
}
static unsigned int chdr(fmap_t *map, uint32_t coff, uint32_t zsize, unsigned int *fu, unsigned int fc, int *ret, cli_ctx *ctx, char *tmpd, struct zip_requests *requests, uint32_t *file_local_offset, uint32_t *file_local_header_size, uint32_t *file_local_data_size)
{
char name[256];
int last = 0;
const uint8_t *ch;
int virus_found = 0;
if (NULL != file_local_offset)
*file_local_offset = 0;
if (NULL != file_local_header_size)
*file_local_header_size = 0;
if (NULL != file_local_data_size)
*file_local_data_size = 0;
if (!(ch = fmap_need_off(map, coff, SIZEOF_CH)) || CH_magic != 0x02014b50) {
if (ch) fmap_unneed_ptr(map, ch, SIZEOF_CH);
cli_dbgmsg("cli_unzip: ch - wrkcomplete\n");
return 0;
}
coff += SIZEOF_CH;
cli_dbgmsg("cli_unzip: ch - flags %x - method %x - csize %x - usize %x - flen %x - elen %x - clen %x - disk %x - off %x\n", CH_flags, CH_method, CH_csize, CH_usize, CH_flen, CH_elen, CH_clen, CH_dsk, CH_off);
if (zsize - coff <= CH_flen) {
cli_dbgmsg("cli_unzip: ch - fname out of file\n");
last = 1;
}
name[0] = '\0';
if (!last) {
unsigned int size = (CH_flen >= sizeof(name)) ? sizeof(name) - 1 : CH_flen;
const char *src = fmap_need_off_once(map, coff, size);
if (src) {
memcpy(name, src, size);
name[size] = '\0';
cli_dbgmsg("cli_unzip: ch - fname: %s\n", name);
}
}
coff += CH_flen;
/* requests do not supply a ctx; also prevent multiple scans */
if (ctx && cli_matchmeta(ctx, name, CH_csize, CH_usize, (CH_flags & F_ENCR) != 0, fc, CH_crc32, NULL) == CL_VIRUS)
virus_found = 1;
if (zsize - coff <= CH_elen && !last) {
cli_dbgmsg("cli_unzip: ch - extra out of file\n");
last = 1;
}
coff += CH_elen;
if (zsize - coff < CH_clen && !last) {
cli_dbgmsg("cli_unzip: ch - comment out of file\n");
last = 1;
}
coff += CH_clen;
if (!requests) {
if (CH_off < zsize - SIZEOF_LH) {
if (NULL != file_local_offset)
*file_local_offset = CH_off;
lhdr(map, CH_off, zsize - CH_off, fu, fc, ch, ret, ctx, tmpd, 1, zip_scan_cb, file_local_header_size, file_local_data_size);
} else
cli_dbgmsg("cli_unzip: ch - local hdr out of file\n");
} else {
int i;
size_t len;
if (!last) {
for (i = 0; i < requests->namecnt; ++i) {
cli_dbgmsg("checking for %i: %s\n", i, requests->names[i]);
len = MIN(sizeof(name) - 1, requests->namelens[i]);
if (!strncmp(requests->names[i], name, len)) {
requests->match = 1;
requests->found = i;
requests->loff = CH_off;
}
}
}
}
if (virus_found == 1)
*ret = CL_VIRUS;
fmap_unneed_ptr(map, ch, SIZEOF_CH);
return (last ? 0 : coff);
}
int cli_unzip(cli_ctx *ctx)
{
unsigned int fc = 0, fu = 0;
int ret = CL_CLEAN;
uint32_t fsize, lhoff = 0, coff = 0;
fmap_t *map = *ctx->fmap;
char *tmpd;
const char *ptr;
int virus_found = 0;
#if HAVE_JSON
int toval = 0;
#endif
int bZipBombDetected = 0;
uint32_t cur_file_local_offset = 0;
uint32_t cur_file_local_header_size = 0;
uint32_t cur_file_local_data_size = 0;
uint32_t prev_file_local_offset = 0;
uint32_t prev_file_local_header_size = 0;
uint32_t prev_file_local_data_size = 0;
cli_dbgmsg("in cli_unzip\n");
fsize = (uint32_t)map->len;
if (sizeof(off_t) != sizeof(uint32_t) && (size_t)fsize != map->len) {
cli_dbgmsg("cli_unzip: file too big\n");
return CL_CLEAN;
}
if (fsize < SIZEOF_CH) {
cli_dbgmsg("cli_unzip: file too short\n");
return CL_CLEAN;
}
if (!(tmpd = cli_gentemp(ctx->engine->tmpdir))) {
return CL_ETMPDIR;
}
if (mkdir(tmpd, 0700)) {
cli_dbgmsg("cli_unzip: Can't create temporary directory %s\n", tmpd);
free(tmpd);
return CL_ETMPDIR;
}
for (coff = fsize - 22; coff > 0; coff--) { /* sizeof(EOC)==22 */
if (!(ptr = fmap_need_off_once(map, coff, 20)))
continue;
if (cli_readint32(ptr) == 0x06054b50) {
uint32_t chptr = cli_readint32(&ptr[16]);
if (!CLI_ISCONTAINED(0, fsize, chptr, SIZEOF_CH)) continue;
coff = chptr;
break;
}
}
if (coff) {
uint32_t nOverlappingFiles = 0;
cli_dbgmsg("cli_unzip: central @%x\n", coff);
while ((coff = chdr(map, coff, fsize, &fu, fc + 1, &ret, ctx, tmpd, NULL, &cur_file_local_offset, &cur_file_local_header_size, &cur_file_local_data_size))) {
fc++;
if (ctx->engine->maxfiles && fu >= ctx->engine->maxfiles) {
cli_dbgmsg("cli_unzip: Files limit reached (max: %u)\n", ctx->engine->maxfiles);
ret = CL_EMAXFILES;
}
if (cli_checktimelimit(ctx) != CL_SUCCESS) {
cli_dbgmsg("cli_unzip: Time limit reached (max: %u)\n", ctx->engine->maxscantime);
ret = CL_ETIMEOUT;
}
/*
* Detect overlapping files and zip bombs.
*/
if ((((cur_file_local_offset > prev_file_local_offset) && (cur_file_local_offset < prev_file_local_offset + prev_file_local_header_size + prev_file_local_data_size)) ||
((prev_file_local_offset > cur_file_local_offset) && (prev_file_local_offset < cur_file_local_offset + cur_file_local_header_size + cur_file_local_data_size))) &&
(cur_file_local_header_size + cur_file_local_data_size > 0)) {
/* Overlapping file detected */
nOverlappingFiles++;
cli_dbgmsg("cli_unzip: Overlapping files detected.\n");
cli_dbgmsg(" previous file end: %u\n", prev_file_local_offset + prev_file_local_header_size + prev_file_local_data_size);
cli_dbgmsg(" current file start: %u\n", cur_file_local_offset);
if (ZIP_MAX_NUM_OVERLAPPING_FILES < nOverlappingFiles) {
if (SCAN_HEURISTICS) {
ret = cli_append_virus(ctx, "Heuristics.Zip.OverlappingFiles");
virus_found = 1;
} else {
ret = CL_EFORMAT;
}
bZipBombDetected = 1;
}
}
prev_file_local_offset = cur_file_local_offset;
prev_file_local_header_size = cur_file_local_header_size;
prev_file_local_data_size = cur_file_local_data_size;
#if HAVE_JSON
if (cli_json_timeout_cycle_check(ctx, &toval) != CL_SUCCESS) {
ret = CL_ETIMEOUT;
}
#endif
if (ret != CL_CLEAN) {
if (ret == CL_VIRUS && SCAN_ALLMATCHES && !bZipBombDetected) {
ret = CL_CLEAN;
virus_found = 1;
} else
break;
}
}
} else
cli_dbgmsg("cli_unzip: central not found, using localhdrs\n");
if (virus_found == 1)
ret = CL_VIRUS;
if (fu <= (fc / 4)) { /* FIXME: make up a sane ratio or remove the whole logic */
fc = 0;
while (ret == CL_CLEAN && lhoff < fsize && (coff = lhdr(map, lhoff, fsize - lhoff, &fu, fc + 1, NULL, &ret, ctx, tmpd, 1, zip_scan_cb, NULL, NULL))) {
fc++;
lhoff += coff;
if (SCAN_ALLMATCHES && ret == CL_VIRUS) {
ret = CL_CLEAN;
virus_found = 1;
}
if (ctx->engine->maxfiles && fu >= ctx->engine->maxfiles) {
cli_dbgmsg("cli_unzip: Files limit reached (max: %u)\n", ctx->engine->maxfiles);
ret = CL_EMAXFILES;
}
#if HAVE_JSON
if (cli_json_timeout_cycle_check(ctx, &toval) != CL_SUCCESS) {
ret = CL_ETIMEOUT;
}
#endif
}
}
if (!ctx->engine->keeptmp) cli_rmdirs(tmpd);
free(tmpd);
if (ret == CL_CLEAN && virus_found)
ret = CL_VIRUS;
return ret;
}
int unzip_single_internal(cli_ctx *ctx, off_t lhoffl, zip_cb zcb)
{
int ret = CL_CLEAN;
unsigned int fu = 0;
uint32_t fsize;
fmap_t *map = *ctx->fmap;
cli_dbgmsg("in cli_unzip_single\n");
fsize = (uint32_t)(map->len - lhoffl);
if (lhoffl < 0 || (size_t)lhoffl > map->len || (sizeof(off_t) != sizeof(uint32_t) && (size_t)fsize != map->len - lhoffl)) {
cli_dbgmsg("cli_unzip: bad offset\n");
return CL_CLEAN;
}
if (fsize < SIZEOF_LH) {
cli_dbgmsg("cli_unzip: file too short\n");
return CL_CLEAN;
}
lhdr(map, lhoffl, fsize, &fu, 0, NULL, &ret, ctx, NULL, 0, zcb, NULL, NULL);
return ret;
}
int cli_unzip_single(cli_ctx *ctx, off_t lhoffl)
{
return unzip_single_internal(ctx, lhoffl, zip_scan_cb);
}
int unzip_search_add(struct zip_requests *requests, const char *name, size_t nlen)
{
cli_dbgmsg("in unzip_search_add\n");
if (requests->namecnt >= MAX_ZIP_REQUESTS) {
cli_dbgmsg("DEBUGGING MESSAGE GOES HERE!\n");
return CL_BREAK;
}
cli_dbgmsg("unzip_search_add: adding %s (len %llu)\n", name, (long long unsigned)nlen);
requests->names[requests->namecnt] = name;
requests->namelens[requests->namecnt] = nlen;
requests->namecnt++;
return CL_SUCCESS;
}
int unzip_search(cli_ctx *ctx, fmap_t *map, struct zip_requests *requests)
{
unsigned int fc = 0;
fmap_t *zmap = map;
size_t fsize;
uint32_t coff = 0;
const char *ptr;
int ret = CL_CLEAN;
#if HAVE_JSON
uint32_t toval = 0;
#endif
cli_dbgmsg("in unzip_search\n");
if ((!ctx && !map) || !requests) {
return CL_ENULLARG;
}
/* get priority to given map over *ctx->fmap */
if (ctx && !map)
zmap = *ctx->fmap;
fsize = zmap->len;
if (sizeof(off_t) != sizeof(uint32_t) && fsize != zmap->len) {
cli_dbgmsg("unzip_search: file too big\n");
return CL_CLEAN;
}
if (fsize < SIZEOF_CH) {
cli_dbgmsg("unzip_search: file too short\n");
return CL_CLEAN;
}
for (coff = fsize - 22; coff > 0; coff--) { /* sizeof(EOC)==22 */
if (!(ptr = fmap_need_off_once(zmap, coff, 20)))
continue;
if (cli_readint32(ptr) == 0x06054b50) {
uint32_t chptr = cli_readint32(&ptr[16]);
if (!CLI_ISCONTAINED(0, fsize, chptr, SIZEOF_CH)) continue;
coff = chptr;
break;
}
}
if (coff) {
cli_dbgmsg("unzip_search: central @%x\n", coff);
while (ret == CL_CLEAN && (coff = chdr(zmap, coff, fsize, NULL, fc + 1, &ret, ctx, NULL, requests, NULL, NULL, NULL))) {
if (requests->match) {
ret = CL_VIRUS;
}
fc++;
if (ctx && ctx->engine->maxfiles && fc >= ctx->engine->maxfiles) {
cli_dbgmsg("cli_unzip: Files limit reached (max: %u)\n", ctx->engine->maxfiles);
ret = CL_EMAXFILES;
}
#if HAVE_JSON
if (ctx && cli_json_timeout_cycle_check(ctx, (int *)(&toval)) != CL_SUCCESS) {
ret = CL_ETIMEOUT;
}
#endif
}
} else {
cli_dbgmsg("unzip_search: cannot locate central directory\n");
}
return ret;
}
int unzip_search_single(cli_ctx *ctx, const char *name, size_t nlen, uint32_t *loff)
{
struct zip_requests requests;
int ret;
cli_dbgmsg("in unzip_search_single\n");
if (!ctx) {
return CL_ENULLARG;
}
memset(&requests, 0, sizeof(struct zip_requests));
if ((ret = unzip_search_add(&requests, name, nlen)) != CL_SUCCESS) {
return ret;
}
if ((ret = unzip_search(ctx, NULL, &requests)) == CL_VIRUS) {
*loff = requests.loff;
}
return ret;
}