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ClamAV is an open source (GPLv2) anti-virus toolkit.
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clamav/libclamav/cvd.c

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/*
* Copyright (C) 2007-2008 Sourcefire, Inc.
*
* Authors: Tomasz Kojm
*
* 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.
*/
#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "zlib.h"
#include <time.h>
#include <errno.h>
#include "clamav.h"
#include "others.h"
#include "dsig.h"
#include "str.h"
#include "cvd.h"
#include "readdb.h"
#define TAR_BLOCKSIZE 512
int cli_untgz(int fd, const char *destdir)
{
char *path, osize[13], name[101], type;
char block[TAR_BLOCKSIZE];
int nbytes, nread, nwritten, in_block = 0, fdd;
unsigned int size, pathlen = strlen(destdir) + 100 + 5;
FILE *outfile = NULL;
struct stat foo;
gzFile *infile;
cli_dbgmsg("in cli_untgz()\n");
if((fdd = dup(fd)) == -1) {
cli_errmsg("cli_untgz: Can't duplicate descriptor %d\n", fd);
return -1;
}
if((infile = gzdopen(fdd, "rb")) == NULL) {
cli_errmsg("cli_untgz: Can't gzdopen() descriptor %d, errno = %d\n", fdd, errno);
if(fstat(fdd, &foo) == 0)
close(fdd);
return -1;
}
path = (char *) cli_calloc(sizeof(char), pathlen);
if(!path) {
cli_errmsg("cli_untgz: Can't allocate memory for path\n");
gzclose(infile);
return -1;
}
while(1) {
nread = gzread(infile, block, TAR_BLOCKSIZE);
if(!in_block && !nread)
break;
if(nread != TAR_BLOCKSIZE) {
cli_errmsg("cli_untgz: Incomplete block read\n");
free(path);
gzclose(infile);
return -1;
}
if(!in_block) {
if (block[0] == '\0') /* We're done */
break;
strncpy(name, block, 100);
name[100] = '\0';
if(strchr(name, '/')) {
cli_errmsg("cli_untgz: Slash separators are not allowed in CVD\n");
free(path);
gzclose(infile);
return -1;
}
snprintf(path, pathlen, "%s/%s", destdir, name);
cli_dbgmsg("cli_untgz: Unpacking %s\n", path);
type = block[156];
switch(type) {
case '0':
case '\0':
break;
case '5':
cli_errmsg("cli_untgz: Directories are not supported in CVD\n");
free(path);
gzclose(infile);
return -1;
default:
cli_errmsg("cli_untgz: Unknown type flag '%c'\n", type);
free(path);
gzclose(infile);
return -1;
}
in_block = 1;
if(outfile) {
if(fclose(outfile)) {
cli_errmsg("cli_untgz: Cannot close file %s\n", path);
free(path);
gzclose(infile);
return -1;
}
outfile = NULL;
}
if(!(outfile = fopen(path, "wb"))) {
cli_errmsg("cli_untgz: Cannot create file %s\n", path);
free(path);
gzclose(infile);
return -1;
}
strncpy(osize, block + 124, 12);
osize[12] = '\0';
if((sscanf(osize, "%o", &size)) == 0) {
cli_errmsg("cli_untgz: Invalid size in header\n");
free(path);
gzclose(infile);
fclose(outfile);
return -1;
}
} else { /* write or continue writing file contents */
nbytes = size > TAR_BLOCKSIZE ? TAR_BLOCKSIZE : size;
nwritten = fwrite(block, 1, nbytes, outfile);
if(nwritten != nbytes) {
cli_errmsg("cli_untgz: Wrote %d instead of %d (%s)\n", nwritten, nbytes, path);
free(path);
gzclose(infile);
return -1;
}
size -= nbytes;
if(size == 0)
in_block = 0;
}
}
if(outfile)
fclose(outfile);
gzclose(infile);
free(path);
return 0;
}
static int cli_tgzload(int fd, struct cl_engine **engine, unsigned int *signo, unsigned int options)
{
char osize[13], name[101];
char block[TAR_BLOCKSIZE];
int nread, fdd, ret;
unsigned int type, size, pad, compr = 1;
off_t off;
struct cli_dbio dbio;
#define CLOSE_DBIO \
if(compr) \
gzclose(dbio.gzs); \
else \
fclose(dbio.fs)
cli_dbgmsg("in cli_tgzload()\n");
lseek(fd, 512, SEEK_SET);
if(cli_readn(fd, block, 7) != 7)
return CL_EFORMAT; /* truncated file? */
if(!strncmp(block, "COPYING", 7))
compr = 0;
lseek(fd, 512, SEEK_SET);
if((fdd = dup(fd)) == -1) {
cli_errmsg("cli_tgzload: Can't duplicate descriptor %d\n", fd);
return CL_EIO;
}
if(compr) {
if((dbio.gzs = gzdopen(fdd, "rb")) == NULL) {
cli_errmsg("cli_tgzload: Can't gzdopen() descriptor %d, errno = %d\n", fdd, errno);
return CL_EIO;
}
dbio.fs = NULL;
} else {
if((dbio.fs = fdopen(fdd, "rb")) == NULL) {
cli_errmsg("cli_tgzload: Can't fdopen() descriptor %d, errno = %d\n", fdd, errno);
return CL_EIO;
}
dbio.gzs = NULL;
}
while(1) {
if(compr)
nread = gzread(dbio.gzs, block, TAR_BLOCKSIZE);
else
nread = fread(block, 1, TAR_BLOCKSIZE, dbio.fs);
if(!nread)
break;
if(nread != TAR_BLOCKSIZE) {
cli_errmsg("cli_tgzload: Incomplete block read\n");
CLOSE_DBIO;
return CL_EMALFDB;
}
if(block[0] == '\0') /* We're done */
break;
strncpy(name, block, 100);
name[100] = '\0';
if(strchr(name, '/')) {
cli_errmsg("cli_tgzload: Slash separators are not allowed in CVD\n");
CLOSE_DBIO;
return CL_EMALFDB;
}
type = block[156];
switch(type) {
case '0':
case '\0':
break;
case '5':
cli_errmsg("cli_tgzload: Directories are not supported in CVD\n");
CLOSE_DBIO;
return CL_EMALFDB;
default:
cli_errmsg("cli_tgzload: Unknown type flag '%c'\n", type);
CLOSE_DBIO;
return CL_EMALFDB;
}
strncpy(osize, block + 124, 12);
osize[12] = '\0';
if((sscanf(osize, "%o", &size)) == 0) {
cli_errmsg("cli_tgzload: Invalid size in header\n");
CLOSE_DBIO;
return CL_EMALFDB;
}
dbio.size = size;
/* cli_dbgmsg("cli_tgzload: Loading %s, size: %u\n", name, size); */
if(compr)
off = (off_t) gzseek(dbio.gzs, 0, SEEK_CUR);
else
off = ftell(dbio.fs);
if(CLI_DBEXT(name)) {
ret = cli_load(name, engine, signo, options, &dbio);
if(ret) {
cli_errmsg("cli_tgzload: Can't load %s\n", name);
CLOSE_DBIO;
return CL_EMALFDB;
}
}
pad = size % TAR_BLOCKSIZE ? (TAR_BLOCKSIZE - (size % TAR_BLOCKSIZE)) : 0;
if(compr) {
if(off == gzseek(dbio.gzs, 0, SEEK_CUR))
gzseek(dbio.gzs, size + pad, SEEK_CUR);
else if(pad)
gzseek(dbio.gzs, pad, SEEK_CUR);
} else {
if(off == ftell(dbio.fs))
fseek(dbio.fs, size + pad, SEEK_CUR);
else if(pad)
fseek(dbio.fs, pad, SEEK_CUR);
}
}
CLOSE_DBIO;
return CL_SUCCESS;
}
struct cl_cvd *cl_cvdparse(const char *head)
{
struct cl_cvd *cvd;
char *pt;
if(strncmp(head, "ClamAV-VDB:", 11)) {
cli_errmsg("cli_cvdparse: Not a CVD file\n");
return NULL;
}
if(!(cvd = (struct cl_cvd *) cli_malloc(sizeof(struct cl_cvd)))) {
cli_errmsg("cl_cvdparse: Can't allocate memory for cvd\n");
return NULL;
}
if(!(cvd->time = cli_strtok(head, 1, ":"))) {
cli_errmsg("cli_cvdparse: Can't parse the creation time\n");
free(cvd);
return NULL;
}
if(!(pt = cli_strtok(head, 2, ":"))) {
cli_errmsg("cli_cvdparse: Can't parse the version number\n");
free(cvd->time);
free(cvd);
return NULL;
}
cvd->version = atoi(pt);
free(pt);
if(!(pt = cli_strtok(head, 3, ":"))) {
cli_errmsg("cli_cvdparse: Can't parse the number of signatures\n");
free(cvd->time);
free(cvd);
return NULL;
}
cvd->sigs = atoi(pt);
free(pt);
if(!(pt = cli_strtok(head, 4, ":"))) {
cli_errmsg("cli_cvdparse: Can't parse the functionality level\n");
free(cvd->time);
free(cvd);
return NULL;
}
cvd->fl = atoi(pt);
free(pt);
if(!(cvd->md5 = cli_strtok(head, 5, ":"))) {
cli_errmsg("cli_cvdparse: Can't parse the MD5 checksum\n");
free(cvd->time);
free(cvd);
return NULL;
}
if(!(cvd->dsig = cli_strtok(head, 6, ":"))) {
cli_errmsg("cli_cvdparse: Can't parse the digital signature\n");
free(cvd->time);
free(cvd->md5);
free(cvd);
return NULL;
}
if(!(cvd->builder = cli_strtok(head, 7, ":"))) {
cli_errmsg("cli_cvdparse: Can't parse the builder name\n");
free(cvd->time);
free(cvd->md5);
free(cvd->dsig);
free(cvd);
return NULL;
}
if((pt = cli_strtok(head, 8, ":"))) {
cvd->stime = atoi(pt);
free(pt);
} else {
cli_dbgmsg("cli_cvdparse: No creation time in seconds (old file format)\n");
cvd->stime = 0;
}
return cvd;
}
struct cl_cvd *cl_cvdhead(const char *file)
{
FILE *fs;
char head[513], *pt;
int i;
unsigned int bread;
if((fs = fopen(file, "rb")) == NULL) {
cli_errmsg("cl_cvdhead: Can't open file %s\n", file);
return NULL;
}
if(!(bread = fread(head, 1, 512, fs))) {
cli_errmsg("cl_cvdhead: Can't read CVD header in %s\n", file);
fclose(fs);
return NULL;
}
fclose(fs);
head[bread] = 0;
if((pt = strpbrk(head, "\n\r")))
*pt = 0;
for(i = bread - 1; i > 0 && (head[i] == ' ' || head[i] == '\n' || head[i] == '\r'); head[i] = 0, i--);
return cl_cvdparse(head);
}
void cl_cvdfree(struct cl_cvd *cvd)
{
free(cvd->time);
free(cvd->md5);
free(cvd->dsig);
free(cvd->builder);
free(cvd);
}
static int cli_cvdverify(FILE *fs, struct cl_cvd *cvdpt, unsigned int cld)
{
struct cl_cvd *cvd;
char *md5, head[513];
int i;
fseek(fs, 0, SEEK_SET);
if(fread(head, 1, 512, fs) != 512) {
cli_errmsg("cli_cvdverify: Can't read CVD header\n");
return CL_ECVD;
}
head[512] = 0;
for(i = 511; i > 0 && (head[i] == ' ' || head[i] == 10); head[i] = 0, i--);
if((cvd = cl_cvdparse(head)) == NULL)
return CL_ECVD;
if(cvdpt)
memcpy(cvdpt, cvd, sizeof(struct cl_cvd));
if(cld) {
cl_cvdfree(cvd);
return CL_SUCCESS;
}
md5 = cli_md5stream(fs, NULL);
cli_dbgmsg("MD5(.tar.gz) = %s\n", md5);
if(strncmp(md5, cvd->md5, 32)) {
cli_dbgmsg("cli_cvdverify: MD5 verification error\n");
free(md5);
cl_cvdfree(cvd);
return CL_EMD5;
}
#ifdef HAVE_LIBGMP
if(cli_versig(md5, cvd->dsig)) {
cli_dbgmsg("cli_cvdverify: Digital signature verification error\n");
free(md5);
cl_cvdfree(cvd);
return CL_EDSIG;
}
#endif
free(md5);
cl_cvdfree(cvd);
return CL_SUCCESS;
}
int cl_cvdverify(const char *file)
{
FILE *fs;
int ret;
if((fs = fopen(file, "rb")) == NULL) {
cli_errmsg("cl_cvdverify: Can't open file %s\n", file);
return CL_EOPEN;
}
ret = cli_cvdverify(fs, NULL, 0);
fclose(fs);
return ret;
}
int cli_cvdload(FILE *fs, struct cl_engine **engine, unsigned int *signo, short warn, unsigned int options, unsigned int cld)
{
char *dir;
struct cl_cvd cvd;
int ret;
time_t s_time;
int cfd;
cli_dbgmsg("in cli_cvdload()\n");
/* verify */
if((ret = cli_cvdverify(fs, &cvd, cld)))
return ret;
if(cvd.stime && warn) {
time(&s_time);
if((int) s_time - cvd.stime > 604800) {
cli_warnmsg("**************************************************\n");
cli_warnmsg("*** The virus database is older than 7 days! ***\n");
cli_warnmsg("*** Please update it as soon as possible. ***\n");
cli_warnmsg("**************************************************\n");
}
}
if(cvd.fl > cl_retflevel()) {
cli_warnmsg("***********************************************************\n");
cli_warnmsg("*** This version of the ClamAV engine is outdated. ***\n");
cli_warnmsg("*** DON'T PANIC! Read http://www.clamav.net/support/faq ***\n");
cli_warnmsg("***********************************************************\n");
}
cfd = fileno(fs);
/* use only operations on file descriptors, and not on the FILE* from here on
* if we seek the FILE*, the underlying descriptor may not seek as expected
* (for example on OpenBSD, cygwin, etc.).
* So seek the descriptor directly.
*/
if(lseek(cfd, 512, SEEK_SET) == -1) {
cli_errmsg("cli_cvdload(): lseek(fs, 512, SEEK_SET) failed\n");
return CL_EIO;
}
if(options & CL_DB_CVDNOTMP) {
return cli_tgzload(cfd, engine, signo, options | CL_DB_OFFICIAL);
} else {
if(!(dir = cli_gentemp(NULL)))
return CL_EMEM;
if(mkdir(dir, 0700)) {
cli_errmsg("cli_cvdload(): Can't create temporary directory %s\n", dir);
free(dir);
return CL_ETMPDIR;
}
if(cli_untgz(cfd, dir)) {
cli_errmsg("cli_cvdload(): Can't unpack CVD file.\n");
free(dir);
return CL_ECVDEXTR;
}
/* load extracted directory */
ret = cl_load(dir, engine, signo, options | CL_DB_OFFICIAL);
cli_rmdirs(dir);
free(dir);
return ret;
}
}