/*
* Copyright (C) 2015-2019 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
*
* Authors: Mickey Sola
*
* 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 <errno.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <signal.h>
#include <pthread.h>
#if defined(FANOTIFY)
#include <sys/fanotify.h>
#endif
#include "shared/optparser.h"
#include "shared/output.h"
#include "libclamav/others.h"
#include "../misc/priv_fts.h"
#include "../misc/utils.h"
#include "../client/client.h"
#include "thread.h"
static pthread_mutex_t onas_scan_lock = PTHREAD_MUTEX_INITIALIZER;
static int onas_scan(struct onas_scan_event *event_data, const char *fname, STATBUF sb, int *infected, int *err, cl_error_t *ret_code);
static cl_error_t onas_scan_safe(struct onas_scan_event *event_data, const char *fname, STATBUF sb, int *infected, int *err, cl_error_t *ret_code);
static cl_error_t onas_scan_thread_scanfile(struct onas_scan_event *event_data, const char *fname, STATBUF sb, int *infected, int *err, cl_error_t *ret_code);
static cl_error_t onas_scan_thread_handle_dir(struct onas_scan_event *event_data, const char *pathname);
static cl_error_t onas_scan_thread_handle_file(struct onas_scan_event *event_data, const char *pathname);
static void onas_scan_thread_exit(int sig);
static void onas_scan_thread_exit(int sig)
{
logg("*ScanOnAccess: onas_scan_thread_exit(), signal %d\n", sig);
pthread_exit(NULL);
}
/**
* @brief Safe-scan wrapper, originally used by inotify and fanotify threads, now exists for error checking/convenience.
*
* Owned by scanthread to try and force multithreaded client archtiecture which better avoids kernel level deadlocks from
* fanotify blocking/prevention.
*/
static int onas_scan(struct onas_scan_event *event_data, const char *fname, STATBUF sb, int *infected, int *err, cl_error_t *ret_code)
{
int ret = 0;
int i = 0;
uint8_t retry_on_error = event_data->bool_opts & ONAS_SCTH_B_RETRY_ON_E;
ret = onas_scan_safe(event_data, fname, sb, infected, err, ret_code);
if (*err) {
switch (*ret_code) {
case CL_EACCES:
case CL_ESTAT:
logg("*ClamMisc: internal issue (daemon could not access directory/file %s)\n", fname);
break;
/* TODO: handle other errors */
case CL_EPARSE:
case CL_EREAD:
case CL_EWRITE:
case CL_EMEM:
case CL_ENULLARG:
default:
logg("~ClamMisc: internal issue (client failed to scan)\n");
}
if (retry_on_error) {
logg("*ClamMisc: reattempting scan ... \n");
while (err) {
ret = onas_scan_safe(event_data, fname, sb, infected, err, ret_code);
i++;
if (*err && i == event_data->retry_attempts) {
*err = 0;
}
}
}
}
return ret;
}
/**
* @brief Thread-safe scan wrapper to ensure there's no processs contention over use of the socket.
*
* This is noticeably slower, and I had no issues running smaller scale tests with it off, but better than sorry until more testing can be done.
*
* TODO: make this configurable?
*/
static cl_error_t onas_scan_safe(struct onas_scan_event *event_data, const char *fname, STATBUF sb, int *infected, int *err, cl_error_t *ret_code)
{
int ret = 0;
int fd = 0;
#if defined(FANOTIFY)
uint8_t b_fanotify;
b_fanotify = event_data->bool_opts & ONAS_SCTH_B_FANOTIFY ? 1 : 0;
if (b_fanotify) {
fd = event_data->fmd->fd;
}
#endif
pthread_mutex_lock(&onas_scan_lock);
ret = onas_client_scan(event_data->tcpaddr, event_data->portnum, event_data->scantype, event_data->maxstream,
fname, fd, event_data->timeout, sb, infected, err, ret_code);
pthread_mutex_unlock(&onas_scan_lock);
return ret;
}
static cl_error_t onas_scan_thread_scanfile(struct onas_scan_event *event_data, const char *fname, STATBUF sb, int *infected, int *err, cl_error_t *ret_code)
{
#if defined(FANOTIFY)
struct fanotify_response res;
uint8_t b_fanotify;
#endif
int ret = 0;
uint8_t b_scan;
uint8_t b_deny_on_error;
if (NULL == event_data || NULL == fname || NULL == infected || NULL == err || NULL == ret_code) {
logg("!ClamWorker: scan failed (NULL arg given)\n");
return CL_ENULLARG;
}
b_scan = event_data->bool_opts & ONAS_SCTH_B_SCAN ? 1 : 0;
b_deny_on_error = event_data->bool_opts & ONAS_SCTH_B_DENY_ON_E ? 1 : 0;
#if defined(FANOTIFY)
b_fanotify = event_data->bool_opts & ONAS_SCTH_B_FANOTIFY ? 1 : 0;
if (b_fanotify) {
res.fd = event_data->fmd->fd;
res.response = FAN_ALLOW;
}
#endif
if (b_scan) {
ret = onas_scan(event_data, fname, sb, infected, err, ret_code);
if (*err && *ret_code != CL_SUCCESS) {
logg("*ClamWorker: scan failed with error code %d\n", *ret_code);
}
#if defined(FANOTIFY)
if (b_fanotify) {
if ((*err && *ret_code && b_deny_on_error) || *infected) {
res.response = FAN_DENY;
}
}
#endif
}
#if defined(FANOTIFY)
if (b_fanotify) {
if (event_data->fmd->mask & FAN_ALL_PERM_EVENTS) {
ret = write(event_data->fan_fd, &res, sizeof(res));
if (ret == -1) {
logg("!ClamWorker: internal error (can't write to fanotify)\n");
if (errno == ENOENT) {
logg("*ClamWorker: permission event has already been written ... recovering ...\n");
} else {
ret = CL_EWRITE;
}
}
}
}
if (b_fanotify) {
#ifdef ONAS_DEBUG
logg("*ClamWorker: closing fd, %d)\n", event_data->fmd->fd);
#endif
if (-1 == close(event_data->fmd->fd)) {
logg("!ClamWorker: internal error (can't close fanotify meta fd, %d)\n", event_data->fmd->fd);
if (errno == EBADF) {
logg("*ClamWorker: fd already closed ... recovering ...\n");
} else {
ret = CL_EUNLINK;
}
}
}
#endif
return ret;
}
static cl_error_t onas_scan_thread_handle_dir(struct onas_scan_event *event_data, const char *pathname)
{
FTS *ftsp = NULL;
int32_t ftspopts = FTS_NOCHDIR | FTS_PHYSICAL | FTS_XDEV;
FTSENT *curr = NULL;
int32_t infected = 0;
int32_t err = 0;
cl_error_t ret_code = CL_SUCCESS;
cl_error_t ret = CL_SUCCESS;
int32_t fres = 0;
STATBUF sb;
char *const pathargv[] = {(char *)pathname, NULL};
if (!(ftsp = _priv_fts_open(pathargv, ftspopts, NULL))) {
ret = CL_EOPEN;
goto out;
}
while ((curr = _priv_fts_read(ftsp))) {
if (curr->fts_info != FTS_D) {
fres = CLAMSTAT(curr->fts_path, &sb);
if (event_data->sizelimit) {
if (fres != 0 || sb.st_size > event_data->sizelimit) {
/* okay to skip w/o allow/deny since dir comes from inotify
* events and (probably) won't block w/ protection enabled */
event_data->bool_opts &= ((uint16_t)~ONAS_SCTH_B_SCAN);
logg("*ClamWorker: size limit surpassed while doing extra scanning ... skipping object ...\n");
}
}
ret = onas_scan_thread_scanfile(event_data, curr->fts_path, sb, &infected, &err, &ret_code);
}
}
out:
if (ftsp) {
_priv_fts_close(ftsp);
}
return ret;
}
static cl_error_t onas_scan_thread_handle_file(struct onas_scan_event *event_data, const char *pathname)
{
STATBUF sb;
int32_t infected = 0;
int32_t err = 0;
cl_error_t ret_code = CL_SUCCESS;
int fres = 0;
cl_error_t ret = 0;
if (NULL == pathname || NULL == event_data) {
return CL_ENULLARG;
}
fres = CLAMSTAT(pathname, &sb);
if (event_data->sizelimit) {
if (fres != 0 || sb.st_size > event_data->sizelimit) {
/* don't skip so we avoid lockups, but don't scan either;
* while it should be obvious, this will unconditionally set
* the bit in the map to 0 regardless of original orientation */
event_data->bool_opts &= ((uint16_t)~ONAS_SCTH_B_SCAN);
}
}
ret = onas_scan_thread_scanfile(event_data, pathname, sb, &infected, &err, &ret_code);
#ifdef ONAS_DEBUG
/* very noisy, debug only */
if (event_data->bool_opts & ONAS_SCTH_B_INOTIFY) {
logg("*ClamWorker: Inotify Scan Results ...\n\tret = %d ...\n\tinfected = %d ...\n\terr = %d ...\n\tret_code = %d\n",
ret, infected, err, ret_code);
} else {
logg("*ClamWorker: Fanotify Scan Results ...\n\tret = %d ...\n\tinfected = %d ...\n\terr = %d ...\n\tret_code = %d\n\tfd = %d\n",
ret, infected, err, ret_code, event_data->fmd->fd);
}
#endif
return ret;
}
/**
* @brief worker thread designed to work with the lovely c-thread-pool library to handle our scanning jobs after our queue thread consumes an event
*
* @param arg this should always be an onas_scan_event struct
*/
void *onas_scan_worker(void *arg)
{
struct onas_scan_event *event_data = (struct onas_scan_event *)arg;
uint8_t b_dir;
uint8_t b_file;
uint8_t b_inotify;
uint8_t b_fanotify;
if (NULL == event_data || NULL == event_data->pathname) {
logg("ClamWorker: invalid worker arguments for scanning thread\n");
if (event_data) {
logg("ClamWorker: pathname is null\n");
}
goto done;
}
/* load in boolean info from event struct; makes for easier reading--you're welcome */
b_dir = event_data->bool_opts & ONAS_SCTH_B_DIR ? 1 : 0;
b_file = event_data->bool_opts & ONAS_SCTH_B_FILE ? 1 : 0;
b_inotify = event_data->bool_opts & ONAS_SCTH_B_INOTIFY ? 1 : 0;
b_fanotify = event_data->bool_opts & ONAS_SCTH_B_FANOTIFY ? 1 : 0;
#if defined(FANOTIFY)
if (b_inotify) {
logg("*ClamWorker: handling inotify event ...\n");
if (b_dir) {
logg("*ClamWorker: performing (extra) scanning on directory '%s'\n", event_data->pathname);
onas_scan_thread_handle_dir(event_data, event_data->pathname);
} else if (b_file) {
logg("*ClamWorker: performing (extra) scanning on file '%s'\n", event_data->pathname);
onas_scan_thread_handle_file(event_data, event_data->pathname);
}
} else if (b_fanotify) {
logg("*ClamWorker: performing scanning on file '%s'\n", event_data->pathname);
onas_scan_thread_handle_file(event_data, event_data->pathname);
} else {
/* something went very wrong, so check if we have an open fd,
* try to close it to resolve any potential lingering permissions event,
* then move to cleanup */
if (event_data->fmd) {
if (event_data->fmd->fd) {
close(event_data->fmd->fd);
goto done;
}
}
}
#endif
done:
/* our job to cleanup event data: worker queue just kicks us off in a thread pool, drops the event object
* from the queue and forgets about us */
if (NULL != event_data) {
if (NULL != event_data->pathname) {
free(event_data->pathname);
event_data->pathname = NULL;
}
#if defined(FANOTIFY)
if (NULL != event_data->fmd) {
free(event_data->fmd);
event_data->fmd = NULL;
}
#endif
free(event_data);
event_data = NULL;
}
return NULL;
}
/**
* @brief Simple utility function for external interfaces to add relevant context information to scan_event struct.
*
* Doing this mapping cuts down significantly on memory overhead when queueing hundreds of these scan_event structs
* especially vs using a copy of a raw context struct.
*
* Other potential design options include giving the event access to the "global" context struct address instead,
* to further cut down on space used, but (among other thread safety concerns) I'd prefer the worker threads not
* have the ability to modify it at all to keep down on potential maintenance headaches in the future.
*/
cl_error_t onas_map_context_info_to_event_data(struct onas_context *ctx, struct onas_scan_event **event_data)
{
if (NULL == ctx || NULL == event_data || NULL == *event_data) {
logg("*ClamScThread: context and scan event struct are null ...\n");
return CL_ENULLARG;
}
(*event_data)->scantype = ctx->scantype;
(*event_data)->timeout = ctx->timeout;
(*event_data)->maxstream = ctx->maxstream;
(*event_data)->fan_fd = ctx->fan_fd;
(*event_data)->sizelimit = ctx->sizelimit;
(*event_data)->retry_attempts = ctx->retry_attempts;
if (ctx->retry_on_error) {
(*event_data)->bool_opts |= ONAS_SCTH_B_RETRY_ON_E;
}
if (ctx->deny_on_error) {
(*event_data)->bool_opts |= ONAS_SCTH_B_DENY_ON_E;
}
if (ctx->isremote) {
(*event_data)->bool_opts |= ONAS_SCTH_B_REMOTE;
(*event_data)->tcpaddr = optget(ctx->clamdopts, "TCPAddr")->strarg;
(*event_data)->portnum = ctx->portnum;
} else {
(*event_data)->tcpaddr = optget(ctx->clamdopts, "LocalSocket")->strarg;
}
return CL_SUCCESS;
}