/*
 *  Copyright (C) 2013-2019 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 *  Copyright (C) 2007-2013 Sourcefire, Inc.
 *
 *  Authors: Tomasz Kojm, Török Edvin
 *
 *  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 <stdlib.h>
#include <string.h>
#ifdef	HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <dirent.h>
#ifndef	_WIN32
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/param.h>
#include <signal.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#endif
#include <pthread.h>

#if defined(HAVE_READDIR_R_3) || defined(HAVE_READDIR_R_2)
#include <limits.h>
#include <stddef.h>
#endif

#include "libclamav/clamav.h"
#include "libclamav/others.h"
#include "libclamav/scanners.h"

#include "shared/idmef_logging.h"
#include "shared/optparser.h"
#include "shared/output.h"
#include "shared/misc.h"

#include "others.h"
#include "scanner.h"
#include "shared.h"
#include "thrmgr.h"
#include "server.h"

#ifdef C_LINUX
dev_t procdev; /* /proc device */
#endif

extern int progexit;
extern time_t reloaded_time;
extern pthread_mutex_t reload_mutex;

void msg_callback(enum cl_msg severity, const char *fullmsg, const char *msg, void *ctx)
{
    struct cb_context *c = ctx;
    const char *filename = (c && c->filename) ? c->filename : "";

    UNUSEDPARAM(fullmsg);

    switch (severity) {
	case CL_MSG_ERROR:
	    logg("^[LibClamAV] %s: %s", filename, msg);
	    break;
	case CL_MSG_WARN:
	    logg("~[LibClamAV] %s: %s", filename, msg);
	    break;
	case CL_MSG_INFO_VERBOSE:
	    logg("*[LibClamAV] %s: %s", filename, msg);
	    break;
	default:
	    logg("$[LibClamAV] %s: %s", filename, msg);
	    break;
    }
}

void hash_callback(int fd, unsigned long long size, const unsigned char *md5, const char *virname, void *ctx)
{
    struct cb_context *c = ctx;
    UNUSEDPARAM(fd);
    UNUSEDPARAM(virname);

    if (!c)
	return;
    c->virsize = size;
    strncpy(c->virhash, (const char *)md5, 32);
    c->virhash[32] = '\0';
}

void clamd_virus_found_cb(int fd, const char *virname, void *ctx)
{
    struct cb_context *c = ctx;
    struct scan_cb_data *d = c->scandata;
    const char *fname;
    
    if (d == NULL)
        return;
    if (!(d->options & CL_SCAN_ALLMATCHES) && !(d->options & CL_SCAN_HEURISTIC_PRECEDENCE))
        return;
    if (virname == NULL)
        return;

    fname = (c && c->filename) ? c->filename : "(filename not set)";

    if (virname) {
        d->infected++;
        conn_reply_virus(d->conn, fname, virname);
        if(c->virsize > 0 && optget(d->opts, "ExtendedDetectionInfo")->enabled)
            logg("~%s: %s(%s:%llu) FOUND\n", fname, virname, c->virhash, c->virsize);
        logg("~%s: %s FOUND\n", fname, virname);
    }

    return;
}

#define BUFFSIZE 1024
int scan_callback(STATBUF *sb, char *filename, const char *msg, enum cli_ftw_reason reason, struct cli_ftw_cbdata *data)
{
    struct scan_cb_data *scandata = data->data;
    const char *virname = NULL;
    int ret;
    int type = scandata->type;
    struct cb_context context;

    /* detect disconnected socket, 
     * this should NOT detect half-shutdown sockets (SHUT_WR) */
    if (send(scandata->conn->sd, &ret, 0, 0) == -1 && errno != EINTR) {
	logg("$Client disconnected while command was active!\n");
	thrmgr_group_terminate(scandata->conn->group);
	if (reason == visit_file)
	    free(filename);
	return CL_BREAK;
    }

    if (thrmgr_group_need_terminate(scandata->conn->group)) {
	logg("^Client disconnected while scanjob was active\n");
	if (reason == visit_file)
	    free(filename);
	return CL_BREAK;
    }
    scandata->total++;
    switch (reason) {
	case error_mem:
	    if (msg)
		logg("!Memory allocation failed during cli_ftw() on %s\n",
		     msg);
	    else
		logg("!Memory allocation failed during cli_ftw()\n");
	    scandata->errors++;
	    return CL_EMEM;
	case error_stat:
	    conn_reply_errno(scandata->conn, msg, "lstat() failed:");
	    logg("^lstat() failed on: %s\n", msg);
	    scandata->errors++;
	    return CL_SUCCESS;
	case warning_skipped_dir:
	    logg("^Directory recursion limit reached, skipping %s\n",
		     msg);
	    return CL_SUCCESS;
	case warning_skipped_link:
	    logg("$Skipping symlink: %s\n", msg);
	    return CL_SUCCESS;
	case warning_skipped_special:
	    if (msg == scandata->toplevel_path)
		conn_reply(scandata->conn, msg, "Not supported file type", "ERROR");
	    logg("*Not supported file type: %s\n", msg);
	    return CL_SUCCESS;
	case visit_directory_toplev:
	    return CL_SUCCESS;
	case visit_file:
	    break;
    }

    /* check whether the file is excluded */
#ifdef C_LINUX
    if(procdev && sb && (sb->st_dev == procdev)) {
	free(filename);
	return CL_SUCCESS;
    }
#endif

    if(sb && sb->st_size == 0) { /* empty file */
	if (msg == scandata->toplevel_path)
	    conn_reply_single(scandata->conn, filename, "Empty file");
	free(filename);
	return CL_SUCCESS;
    }

    if (type == TYPE_MULTISCAN) {
	client_conn_t *client_conn = (client_conn_t *) calloc(1, sizeof(struct client_conn_tag));
	if(client_conn) {
	    client_conn->scanfd = -1;
	    client_conn->sd = scandata->odesc;
	    client_conn->filename = filename;
	    client_conn->cmdtype = COMMAND_MULTISCANFILE;
	    client_conn->term = scandata->conn->term;
	    client_conn->options = scandata->options;
	    client_conn->opts = scandata->opts;
	    client_conn->group = scandata->group;
	    if(cl_engine_addref(scandata->engine)) {
		logg("!cl_engine_addref() failed\n");
		free(filename);
		free(client_conn);
		return CL_EMEM;
	    } else {
		client_conn->engine = scandata->engine;
		pthread_mutex_lock(&reload_mutex);
		client_conn->engine_timestamp = reloaded_time;
		pthread_mutex_unlock(&reload_mutex);
		if(!thrmgr_group_dispatch(scandata->thr_pool, scandata->group, client_conn, 1)) {
		    logg("!thread dispatch failed\n");
		    cl_engine_free(scandata->engine);
		    free(filename);
		    free(client_conn);
		    return CL_EMEM;
		}
	    }
	} else {
	    logg("!Can't allocate memory for client_conn\n");
	    scandata->errors++;
	    free(filename);
	    return CL_EMEM;
	}
	return CL_SUCCESS;
    }

    if (access(filename, R_OK)) {
	if (conn_reply(scandata->conn, filename, "Access denied.", "ERROR") == -1) {
	    free(filename);
	    return CL_ETIMEOUT;
	}
	logg("*Access denied: %s\n", filename);
	scandata->errors++;
	free(filename);
	return CL_SUCCESS;
    }

    thrmgr_setactivetask(filename, NULL);
    context.filename = filename;
    context.virsize = 0;
    context.scandata = scandata;
    ret = cl_scanfile_callback(filename, &virname, &scandata->scanned, scandata->engine, scandata->options, &context);
    thrmgr_setactivetask(NULL, NULL);

    if (thrmgr_group_need_terminate(scandata->conn->group)) {
	free(filename);
	logg("*Client disconnected while scanjob was active\n");
	return ret == CL_ETIMEOUT ? ret : CL_BREAK;
    }

    if ((ret == CL_VIRUS) && (virname == NULL)) {
        logg("*%s: reported CL_VIRUS but no virname returned!\n", filename);
        ret = CL_EMEM;
    }

    if (ret == CL_VIRUS) {

         if (scandata->options & CL_SCAN_ALLMATCHES || (scandata->infected && scandata->options & CL_SCAN_HEURISTIC_PRECEDENCE)) {
            if(optget(scandata->opts, "PreludeEnable")->enabled){
                prelude_logging(filename, virname, context.virhash, context.virsize);
            }
            virusaction(filename, virname, scandata->opts);
        } else {
           scandata->infected++;
            if (conn_reply_virus(scandata->conn, filename, virname) == -1) {
                free(filename);
                return CL_ETIMEOUT;
            }
            if(optget(scandata->opts, "PreludeEnable")->enabled){
                prelude_logging(filename, virname, context.virhash, context.virsize);
            }

            if(context.virsize && optget(scandata->opts, "ExtendedDetectionInfo")->enabled)
                logg("~%s: %s(%s:%llu) FOUND\n", filename, virname, context.virhash, context.virsize);
            else
                logg("~%s: %s FOUND\n", filename, virname);
            virusaction(filename, virname, scandata->opts);
        }
    } else if (ret != CL_CLEAN) {
	scandata->errors++;
	if (conn_reply(scandata->conn, filename, cl_strerror(ret), "ERROR") == -1) {
	    free(filename);
	    return CL_ETIMEOUT;
	}
	logg("~%s: %s ERROR\n", filename, cl_strerror(ret));
    } else if (logok) {
	logg("~%s: OK\n", filename);
    }

    free(filename);

    if(ret == CL_EMEM) /* stop scanning */
	return ret;

    if (type == TYPE_SCAN) {
	/* virus -> break */
	return ret;
    }

    /* keep scanning always */
    return CL_SUCCESS;
}

int scan_pathchk(const char *path, struct cli_ftw_cbdata *data)
{
	struct scan_cb_data *scandata = data->data;
	const struct optstruct *opt;
	STATBUF statbuf;

    if((opt = optget(scandata->opts, "ExcludePath"))->enabled) {
	while(opt) {
	    if(match_regex(path, opt->strarg) == 1) {
		if(scandata->type != TYPE_MULTISCAN)
		    conn_reply_single(scandata->conn, path, "Excluded");
		return 1;
	    }
	    opt = (const struct optstruct *) opt->nextarg;
	}
    }

    if(!optget(scandata->opts, "CrossFilesystems")->enabled) {
	if(CLAMSTAT(path, &statbuf) == 0) {
	    if(statbuf.st_dev != scandata->dev) {
		if(scandata->type != TYPE_MULTISCAN)
		    conn_reply_single(scandata->conn, path, "Excluded (another filesystem)");
		return 1;
	    }
	}
    }

    return 0;
}

int scanfd(const client_conn_t *conn, unsigned long int *scanned,
	   const struct cl_engine *engine,
	   unsigned int options, const struct optstruct *opts, int odesc, int stream)
{
    int ret, fd = conn->scanfd;
	const char *virname;
	STATBUF statbuf;
	struct cb_context context;
	char fdstr[32];
	const char*reply_fdstr;

    UNUSEDPARAM(odesc);

	if (stream) {
	    struct sockaddr_in sa;
	    socklen_t salen = sizeof(sa);
	    if(getpeername(conn->sd, (struct sockaddr *)&sa, &salen) || salen > sizeof(sa) || sa.sin_family != AF_INET)
		strncpy(fdstr, "instream(local)", sizeof(fdstr));
	    else
		snprintf(fdstr, sizeof(fdstr), "instream(%s@%u)", inet_ntoa(sa.sin_addr), ntohs(sa.sin_port));
	    reply_fdstr = "stream";
	} else {
	    snprintf(fdstr, sizeof(fdstr), "fd[%d]", fd);
	    reply_fdstr = fdstr;
	}
	if(FSTAT(fd, &statbuf) == -1 || !S_ISREG(statbuf.st_mode)) {
		logg("%s: Not a regular file. ERROR\n", fdstr);
		if (conn_reply(conn, reply_fdstr, "Not a regular file", "ERROR") == -1)
		    return CL_ETIMEOUT;
		return -1;
	}

	thrmgr_setactivetask(fdstr, NULL);
	context.filename = fdstr;
	context.virsize = 0;
        context.scandata = NULL;
	ret = cl_scandesc_callback(fd, &virname, scanned, engine, options, &context);
	thrmgr_setactivetask(NULL, NULL);

	if (thrmgr_group_need_terminate(conn->group)) {
	    logg("*Client disconnected while scanjob was active\n");
	    return ret == CL_ETIMEOUT ? ret : CL_BREAK;
	}

	if(ret == CL_VIRUS) {
		if (conn_reply_virus(conn, reply_fdstr, virname) == -1)
		    ret = CL_ETIMEOUT;
		if(context.virsize && optget(opts, "ExtendedDetectionInfo")->enabled)
		    logg("%s: %s(%s:%llu) FOUND\n", fdstr, virname, context.virhash, context.virsize);
		else
		    logg("%s: %s FOUND\n", fdstr, virname);
		virusaction(reply_fdstr, virname, opts);
	} else if(ret != CL_CLEAN) {
		if (conn_reply(conn, reply_fdstr, cl_strerror(ret), "ERROR") == -1)
		    ret = CL_ETIMEOUT;
		logg("%s: %s ERROR\n", fdstr, cl_strerror(ret));
	} else {
		if (conn_reply_single(conn, reply_fdstr, "OK") == CL_ETIMEOUT)
		    ret = CL_ETIMEOUT;
		if(logok)
			logg("%s: OK\n", fdstr);
	}
	return ret;
}

int scanstream(int odesc, unsigned long int *scanned, const struct cl_engine *engine, unsigned int options, const struct optstruct *opts, char term)
{
	int ret, sockfd, acceptd;
	int tmpd, bread, retval, firsttimeout, timeout, btread;
	unsigned int port = 0, portscan, min_port, max_port;
	unsigned long int quota = 0, maxsize = 0;
	short bound = 0;
	const char *virname;
	char buff[FILEBUFF];
	char peer_addr[32];
	struct cb_context context;
	struct sockaddr_in server;
	struct sockaddr_in peer;
	socklen_t addrlen;
	char *tmpname;


    min_port = optget(opts, "StreamMinPort")->numarg;
    max_port = optget(opts, "StreamMaxPort")->numarg;

    /* search for a free port to bind to */
    port = cli_rndnum(max_port - min_port);
    bound = 0;
    for (portscan = 0; portscan < 1000; portscan++) {
	port = (port - 1) % (max_port - min_port + 1);

	memset((char *) &server, 0, sizeof(server));
	server.sin_family = AF_INET;
	server.sin_port = htons(min_port + port);
	server.sin_addr.s_addr = htonl(INADDR_ANY);

	if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
	    continue;

	if(bind(sockfd, (struct sockaddr *) &server, (socklen_t)sizeof(struct sockaddr_in)) == -1)
	    closesocket(sockfd);
	else {
	    bound = 1;
	    break;
	}
    }
    port += min_port;

    timeout = optget(opts, "ReadTimeout")->numarg;
    firsttimeout = optget(opts, "CommandReadTimeout")->numarg;

    if(!bound) {
	logg("!ScanStream: Can't find any free port.\n");
	mdprintf(odesc, "Can't find any free port. ERROR%c", term);
	return -1;
    } else {
	if (listen(sockfd, 1) == -1) {
        logg("!ScanStream: listen() error on socket. Error returned is %s.\n", strerror(errno));
        closesocket(sockfd);
        return -1;
    }
	if(mdprintf(odesc, "PORT %u%c", port, term) <= 0) {
	    logg("!ScanStream: error transmitting port.\n");
	    closesocket(sockfd);
	    return -1;
	}
    }

    retval = poll_fd(sockfd, firsttimeout, 0);
    if (!retval || retval == -1) {
	const char *reason = !retval ? "timeout" : "poll";
	mdprintf(odesc, "Accept %s. ERROR%c", reason, term);
	logg("!ScanStream %u: accept %s.\n", port, reason);
	closesocket(sockfd);
	return -1;
    }

    addrlen = sizeof(peer);
    if((acceptd = accept(sockfd, (struct sockaddr *) &peer, (socklen_t *)&addrlen)) == -1) {
	closesocket(sockfd);
	mdprintf(odesc, "accept() ERROR%c", term);
	logg("!ScanStream %u: accept() failed.\n", port);
	return -1;
    }

    *peer_addr = '\0';
    inet_ntop(peer.sin_family, &peer.sin_addr, peer_addr, sizeof(peer_addr));
    logg("*Accepted connection from %s on port %u, fd %d\n", peer_addr, port, acceptd);

    if(cli_gentempfd(optget(opts, "TemporaryDirectory")->strarg, &tmpname, &tmpd)) {
	shutdown(sockfd, 2);
	closesocket(sockfd);
	closesocket(acceptd);
	mdprintf(odesc, "cli_gentempfd() failed. ERROR%c", term);
	logg("!ScanStream(%s@%u): Can't create temporary file.\n", peer_addr, port);
	return -1;
    }

    quota = maxsize = optget(opts, "StreamMaxLength")->numarg;

    while((retval = poll_fd(acceptd, timeout, 0)) == 1) {
	/* only read up to max */
	btread = (maxsize && (quota < sizeof(buff))) ? quota : sizeof(buff);
	if (!btread) {
		logg("^ScanStream(%s@%u): Size limit reached (max: %lu)\n", peer_addr, port, maxsize);
		break; /* Scan what we have */
	}
	bread = recv(acceptd, buff, btread, 0);
	if(bread <= 0)
	    break;

	quota -= bread;

	if(writen(tmpd, buff, bread) != bread) {
	    shutdown(sockfd, 2);
	    closesocket(sockfd);
	    closesocket(acceptd);
	    mdprintf(odesc, "Temporary file -> write ERROR%c", term);
	    logg("!ScanStream(%s@%u): Can't write to temporary file.\n", peer_addr, port);
	    close(tmpd);
	    if(!optget(opts, "LeaveTemporaryFiles")->enabled)
		unlink(tmpname);
	    free(tmpname);
	    return -1;
	}
    }

    switch(retval) {
	case 0: /* timeout */
	    mdprintf(odesc, "read timeout ERROR%c", term);
	    logg("!ScanStream(%s@%u): read timeout.\n", peer_addr, port);
	    break;
	case -1:
	    mdprintf(odesc, "read poll ERROR%c", term);
	    logg("!ScanStream(%s@%u): read poll failed.\n", peer_addr, port);
	    break;
    }

    if(retval == 1) {
	lseek(tmpd, 0, SEEK_SET);
	thrmgr_setactivetask(peer_addr, NULL);
	context.filename = peer_addr;
	context.virsize = 0;
        context.scandata = NULL;
	ret = cl_scandesc_callback(tmpd, &virname, scanned, engine, options, &context);
	thrmgr_setactivetask(NULL, NULL);
    } else {
    	ret = -1;
    }
    close(tmpd);
    if(!optget(opts, "LeaveTemporaryFiles")->enabled)
	unlink(tmpname);
    free(tmpname);

    closesocket(acceptd);
    closesocket(sockfd);

    if(ret == CL_VIRUS) {
	if(context.virsize && optget(opts, "ExtendedDetectionInfo")->enabled) {
	    mdprintf(odesc, "stream: %s(%s:%llu) FOUND%c", virname, context.virhash, context.virsize, term);
	    logg("stream(%s@%u): %s(%s:%llu) FOUND\n", peer_addr, port, virname, context.virhash, context.virsize);
	} else {
	    mdprintf(odesc, "stream: %s FOUND%c", virname, term);
	    logg("stream(%s@%u): %s FOUND\n", peer_addr, port, virname);
	}
	virusaction("stream", virname, opts);
    } else if(ret != CL_CLEAN) {
    	if(retval == 1) {
	    mdprintf(odesc, "stream: %s ERROR%c", cl_strerror(ret), term);
	    logg("stream(%s@%u): %s ERROR\n", peer_addr, port, cl_strerror(ret));
	}
    } else {
	mdprintf(odesc, "stream: OK%c", term);
        if(logok)
	    logg("stream(%s@%u): OK\n", peer_addr, port); 
    }

    return ret;
}
