ftpd.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 1,298 行 · 第 1/2 页

#ifndef lint
static	char	*sccsid = "@(#)ftpd.c	4.3	(ULTRIX)	9/4/90";
#endif lint

/************************************************************************
 *									*
 *			Copyright (c) 1984,1988,1989 by			*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/
/*
 * Copyright (c) 1985 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */
/*
#ifndef lint
char copyright[] =
"Copyright (c) 1985 Regents of the University of California.\n\
 All rights reserved.\n";
#endif not lint

#ifndef lint
static char sccsid[] = "ftpd.c	5.10 (Berkeley) 9/4/87";
#endif not lint
*/
/*
 * Modification History:
 *
 * 07-Aug-90	dlong
 *	Generate better audit records and allow more parameters to
 *	reply().
 *
 * 29-Mar-90	dlong
 *	Get kerberos ticket.
 *
 * 15-Aug-89	dlong
 *	Support enhanced security when logging in.
 *
 * 05-Nov-88	jsd
 *	Use sgetpwnam() to avoid security hole
 *
 * 09-Jun-88	Mark Parenti
 *	Changed signal handlers to void.
 *
 */
/*
 * FTP server.
 */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/wait.h>

#include <netinet/in.h>

#include <arpa/ftp.h>
#include <arpa/inet.h>
#include <arpa/telnet.h>

#include <varargs.h>
#include <stdio.h>
#include <signal.h>
#include <pwd.h>
#include <setjmp.h>
#include <netdb.h>
#include <errno.h>
#include <strings.h>
#include <syslog.h>
#include <sys/svcinfo.h>
#include <sys/audit.h>
#include <auth.h>
#ifdef	AUTHEN
#include <krb.h>
#endif	AUTHEN

/*
 * File containing login names
 * NOT to be used on this machine.
 * Commonly used to disallow uucp.
 */
#define	FTPUSERS	"/etc/ftpusers"

extern	int errno;
extern	char *sys_errlist[];
extern	char *crypt();
extern	char version[];
extern	char *home;		/* pointer to home directory for glob */
extern	FILE *popen(), *fopen(), *freopen();
extern	int  pclose(), fclose();
extern	char *getline();
extern	char cbuf[];

struct	sockaddr_in ctrl_addr;
struct	sockaddr_in data_source;
struct	sockaddr_in data_dest;
struct	sockaddr_in his_addr;

int	data;
jmp_buf	errcatch, urgcatch;
int	logged_in;
struct	passwd *pw;
int	debug;
int	timeout = 900;    /* timeout after 15 minutes of inactivity */
int	logging;
int	guest;
int	wtmp;
int	type;
int	form;
int	stru;			/* avoid C keyword */
int	mode;
int	usedefault = 1;		/* for data transfers */
int	pdata;			/* for passive mode */
int	unique;
int	transflag;
char	tmpline[7];
char	hostname[32];
char	remotehost[32];

/*
 * Timeout intervals for retrying connections
 * to hosts that don't accept PORT cmds.  This
 * is a kludge, but given the problems with TCP...
 */
#define	SWAITMAX	90	/* wait at most 90 seconds */
#define	SWAITINT	5	/* interval between retries */

int	swaitmax = SWAITMAX;
int	swaitint = SWAITINT;

void	lostconn();
void	myoob();
FILE	*getdatasock(), *dataconn();

main(argc, argv)
	int argc;
	char *argv[];
{
	int addrlen, on = 1;
	long pgid;
	char *cp;
#ifdef AUTHEN
	int i;
	char namebuf[ANAME_SZ];
	char *ptr;
	struct svcinfo *svcp;
#endif AUTHEN

	addrlen = sizeof (his_addr);
	if (getpeername(0, &his_addr, &addrlen) < 0) {
		syslog(LOG_ERR, "getpeername (%s): %m",argv[0]);
		exit(1);
	}
	addrlen = sizeof (ctrl_addr);
	if (getsockname(0, (char *) &ctrl_addr, &addrlen) < 0) {
		syslog(LOG_ERR, "getsockname (%s): %m",argv[0]);
		exit(1);
	}
	data_source.sin_port = htons(ntohs(ctrl_addr.sin_port) - 1);
	debug = 0;
#ifdef 43BSD
	openlog("ftpd", LOG_PID, LOG_DAEMON);
#else
	openlog("ftpd", LOG_PID);
#endif 43BSD
	argc--, argv++;
	while (argc > 0 && *argv[0] == '-') {
		for (cp = &argv[0][1]; *cp; cp++) switch (*cp) {

		case 'v':
			debug = 1;
			break;

		case 'd':
			debug = 1;
			break;

		case 'l':
			logging = 1;
			break;

		case 't':
			timeout = atoi(++cp);
			goto nextopt;
			break;

		default:
			fprintf(stderr, "ftpd: Unknown flag -%c ignored.\n",
			     *cp);
			break;
		}
nextopt:
		argc--, argv++;
	}
/*
 * Fire up kerberos
 */

#ifdef AUTHEN
        if((svcp = getsvc()) == NULL)
                {
                fputs("Cannot access security type\n", stderr);
                }
        if(svcp->svcauth.seclevel >= SEC_UPGRADE)
                {
                for (i = 0 ; svcp->svcpath[SVC_AUTH][i] != SVC_LAST; i++)
                        if (svcp->svcpath[SVC_AUTH][i] == SVC_BIND) {
                                if(gethostname(namebuf, sizeof(namebuf)) == -1)
                                        {
                                        fputs("gethostname failure\n", stderr);
                                        }

			if((ptr = index(namebuf, '.')) != (char *)0)
				*ptr = '\0';

                        if(krb_svc_init("hesiod", namebuf, (char *)NULL, 0,
                                (char *)NULL, "/var/dss/kerberos/tkt/tkt.ftpd")
                                        != RET_OK) {
                                fputs("Kerberos initialization failure\n", stderr);
                                }
                        }
                }
#endif AUTHEN
	(void) freopen("/dev/null", "w", stderr);
	(void) signal(SIGPIPE, lostconn);
	(void) signal(SIGCHLD, SIG_IGN);
	if (signal(SIGURG, myoob) < 0) {
		syslog(LOG_ERR, "signal: %m");
	}
	/* handle urgent data inline */
#ifdef SO_OOBINLINE
	if (setsockopt(0, SOL_SOCKET, SO_OOBINLINE, (char *)&on, sizeof(on)) < 0) {
		syslog(LOG_ERR, "setsockopt: %m");
	}
#endif SO_OOBINLINE
	pgid = getpid();
	if (ioctl(fileno(stdin), SIOCSPGRP, (char *) &pgid) < 0) {
		syslog(LOG_ERR, "ioctl: %m");
	}
	dolog(&his_addr);
	/* do telnet option negotiation here */
	/*
	 * Set up default state
	 */
	logged_in = 0;
	data = -1;
	type = TYPE_A;
	form = FORM_N;
	stru = STRU_F;
	mode = MODE_S;
	tmpline[0] = '\0';
	(void) gethostname(hostname, sizeof (hostname));
	reply(220, "%s FTP server (%s) ready.",
		hostname, version);
	for (;;) {
		(void) setjmp(errcatch);
		(void) yyparse();
	}
}

void
lostconn()
{

	if (debug)
		syslog(LOG_DEBUG, "lost connection");
	dologout(-1);
}

/*
 * Helper function for sgetpwnam().
 */
char *
sgetsave(s)
	char *s;
{
#ifdef notdef
	char *new = strdup(s);
#else
	char *malloc();
	char *new = malloc((unsigned) strlen(s) + 1);
#endif
	
	if (new == NULL) {
		reply(553, "Local resource failure");
		dologout(1);
	}
#ifndef notdef
	(void) strcpy(new, s);
#endif
	return (new);
}

/*
 * Save the result of a getpwnam.  Used for USER command, since
 * the data returned must not be clobbered by any other command
 * (e.g., globbing).
 */
struct passwd *
sgetpwnam(name)
	char *name;
{
	static struct passwd save;
	register struct passwd *p;
	char *sgetsave();

	if ((p = getpwnam(name)) == NULL)
		return (p);
	if (save.pw_name) {
		free(save.pw_name);
		free(save.pw_passwd);
		free(save.pw_comment);
		free(save.pw_gecos);
		free(save.pw_dir);
		free(save.pw_shell);
	}
	save = *p;
	save.pw_name = sgetsave(p->pw_name);
	save.pw_passwd = sgetsave(p->pw_passwd);
	save.pw_comment = sgetsave(p->pw_comment);
	save.pw_gecos = sgetsave(p->pw_gecos);
	save.pw_dir = sgetsave(p->pw_dir);
	save.pw_shell = sgetsave(p->pw_shell);
	return (&save);
}

static char aud_msg[BUFSIZ];
pass(passwd)
	char *passwd;
{
	AUTHORIZATION *auth=NULL, *getauthuid();
	char *xpasswd;
	extern int sec_level;
	char tmask[AUD_NPARAM+1];
	char *ar[AUD_NPARAM];
	int i=0;

	if (logged_in || pw == NULL) {
		reply(503, "Login with USER first.");
		return;
	}
	tmask[i] = T_LOGIN;
	ar[i++] = pw->pw_name;
	tmask[i] = T_HOMEDIR;
	ar[i++] = pw->pw_dir;
	tmask[i] = T_SERVICE;
	ar[i++] = "ftpd";
	tmask[i] = T_HOSTADDR2;
	ar[i++] = (char *) his_addr.sin_addr;
	if (!guest) {		/* "ftp" is only account allowed no password */
		config_auth();
		if(sec_level < SEC_UPGRADE) {
			xpasswd = crypt(passwd, pw->pw_passwd);
			/* The strcmp does not catch null passwords! */
			if (*pw->pw_passwd == '\0' || strcmp(xpasswd, pw->pw_passwd)) {
				reply(530, "Login incorrect.");
				goto bad;
			}
		} else {
			if(!checkpass(pw->pw_uid, passwd) || ((auth=getauthuid(pw->pw_uid)) == NULL)) {
				reply(530, "Login incorrect.");
				goto bad;
			}
		}
	}
	setegid(pw->pw_gid);
	initgroups(pw->pw_name, pw->pw_gid);
	if (chdir(pw->pw_dir)) {
		reply(530, "User %s: can't change directory to %s.",
			pw->pw_name, pw->pw_dir);
		goto bad;
	}

	/* grab wtmp before chroot */
	wtmp = open("/usr/adm/wtmp", O_WRONLY|O_APPEND);
	if (guest && chroot(pw->pw_dir) < 0) {
		reply(550, "Can't set guest privileges.");
		if (wtmp >= 0) {
			(void) close(wtmp);
			wtmp = -1;
		}
		goto bad;
	}
	if (!guest)
		reply(230, "User %s logged in.", pw->pw_name);
	else
		reply(230, "Guest login ok, access restrictions apply.");
	logged_in = 1;
	dologin(pw);
	if(auth) {
		if(audcntl(SET_PROC_ACNTL, (char *) 0, 0, auth->a_audit_control, 0) < 0) {
			reply(530, "audcntl error.");
			goto bad;
		}
		if(audcntl(SET_PROC_AMASK, auth->a_audit_mask, SYSCALL_MASK_LEN+TRUSTED_MASK_LEN, 0) < 0) {
			reply(530, "audit mask error.");
			goto bad;
		}
		if(audcntl(SETPAID, (char *) 0, 0, 0, auth->a_audit_id) < 0) {
			reply(530, "error setting audit ID.");
			goto bad;
		}
	}
	if(*aud_msg) {
		tmask[i] = T_CHARP;
		ar[i++] = aud_msg;
	}
	tmask[i] = T_RESULT;
	ar[i++] = (char *) 0;
	tmask[i] = '\0';
	audgen(LOGIN, tmask, ar);
	seteuid(pw->pw_uid);
	home = pw->pw_dir;		/* home dir for globbing */
	return;
bad:
	seteuid(0);
	if(*aud_msg) {
		tmask[i] = T_CHARP;
		ar[i++] = aud_msg;
	}
	tmask[i] = T_ERROR;
	ar[i++] = (char *) 1;
	tmask[i] = '\0';
	audgen(LOGIN, tmask, ar);
	pw = NULL;
}

retrieve(cmd, name)
	char *cmd, *name;
{
	FILE *fin, *dout;
	struct stat st;
	int (*closefunc)(), tmp;

	if (cmd == 0) {
#ifdef notdef
		/* no remote command execution -- it's a security hole */
		if (*name == '|')
			fin = popen(name + 1, "r"), closefunc = pclose;
		else
#endif
			fin = fopen(name, "r"), closefunc = fclose;
	} else {
		char line[BUFSIZ];

		(void) sprintf(line, cmd, name), name = line;
		fin = popen(line, "r"), closefunc = pclose;
	}
	if (fin == NULL) {
		if (errno != 0)
			reply(550, "%s: %s.", name, sys_errlist[errno]);
		return;
	}
	st.st_size = 0;
	if (cmd == 0 &&
	    (stat(name, &st) < 0 || (st.st_mode&S_IFMT) != S_IFREG)) {
		reply(550, "%s: not a plain file.", name);
		goto done;
	}
	dout = dataconn(name, st.st_size, "w");
	if (dout == NULL)
		goto done;
	if ((tmp = send_data(fin, dout)) > 0 || ferror(dout) > 0) {
		reply(550, "%s: %s.", name, sys_errlist[errno]);
	}
	else if (tmp == 0) {
		reply(226, "Transfer complete.");
	}
	(void) fclose(dout);
	data = -1;
	pdata = -1;
done:
	(*closefunc)(fin);
}

store(name, mode)
	char *name, *mode;
{
	FILE *fout, *din;
	int (*closefunc)(), dochown = 0, tmp;
	char *gunique(), *local;

#ifdef notdef
	/* no remote command execution -- it's a security hole */
	if (name[0] == '|')
		fout = popen(&name[1], "w"), closefunc = pclose;
	else
#endif
	{
		struct stat st;

		local = name;
		if (stat(name, &st) < 0) {
			dochown++;
		}
		else if (unique) {
			if ((local = gunique(name)) == NULL) {
				return;
			}
			dochown++;
		}
		fout = fopen(local, mode), closefunc = fclose;
	}
	if (fout == NULL) {
		reply(553, "%s: %s.", local, sys_errlist[errno]);
		return;
	}
	din = dataconn(local, (off_t)-1, "r");
	if (din == NULL)
		goto done;
	if ((tmp = receive_data(din, fout)) > 0 || ferror(fout) > 0) {
		reply(552, "%s: %s.", local, sys_errlist[errno]);
	}
	else if (tmp == 0 && !unique) {
		reply(226, "Transfer complete.");
	}
	else if (tmp == 0 && unique) {
		reply(226, "Transfer complete (unique file name:%s).", local);
	}
	(void) fclose(din);
	data = -1;
	pdata = -1;
done:
	if (dochown)
		(void) chown(local, pw->pw_uid, -1);
	(*closefunc)(fout);
}

FILE *
getdatasock(mode)
	char *mode;
{
	int s, on = 1;

	if (data >= 0)
		return (fdopen(data, mode));
	s = socket(AF_INET, SOCK_STREAM, 0);
	if (s < 0)
		return (NULL);
	seteuid(0);
	if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *) &on, sizeof (on)) < 0)
		goto bad;
	/* anchor socket to avoid multi-homing problems */
	data_source.sin_family = AF_INET;
	data_source.sin_addr = ctrl_addr.sin_addr;
	if (bind(s, &data_source, sizeof (data_source)) < 0)
		goto bad;
	seteuid(pw->pw_uid);
	return (fdopen(s, mode));
bad:
	seteuid(pw->pw_uid);
	(void) close(s);
	return (NULL);
}

FILE *
dataconn(name, size, mode)
	char *name;
	off_t size;
	char *mode;
{
	char sizebuf[32];
	FILE *file;
	int retry = 0;

	if (size >= 0)
		(void) sprintf (sizebuf, " (%ld bytes)", size);
	else
		(void) strcpy(sizebuf, "");
	if (pdata > 0) {
		struct sockaddr_in from;
		int s, fromlen = sizeof(from);

		s = accept(pdata, &from, &fromlen);
		if (s < 0) {
			reply(425, "Can't open data connection.");
			(void) close(pdata);
			pdata = -1;
			return(NULL);
		}
		(void) close(pdata);
		pdata = s;
		reply(150, "Openning data connection for %s (%s,%d)%s.",
		     name, inet_ntoa(from.sin_addr),
		     ntohs(from.sin_port), sizebuf);
		return(fdopen(pdata, mode));
	}
	if (data >= 0) {
		reply(125, "Using existing data connection for %s%s.",
		    name, sizebuf);
		usedefault = 1;
		return (fdopen(data, mode));
	}
	if (usedefault)
		data_dest = his_addr;
	usedefault = 1;
	file = getdatasock(mode);
	if (file == NULL) {
		reply(425, "Can't create data socket (%s,%d): %s.",
		    inet_ntoa(data_source.sin_addr),
		    ntohs(data_source.sin_port),
		    sys_errlist[errno]);
		return (NULL);
	}
	data = fileno(file);
	while (connect(data, &data_dest, sizeof (data_dest)) < 0) {
		if (errno == EADDRINUSE && retry < swaitmax) {
			sleep((unsigned) swaitint);
			retry += swaitint;
			continue;
		}
		reply(425, "Can't build data connection: %s.",
		    sys_errlist[errno]);
		(void) fclose(file);
		data = -1;
		return (NULL);
	}
	reply(150, "Opening data connection for %s (%s,%d)%s.",
	    name, inet_ntoa(data_dest.sin_addr),
	    ntohs(data_dest.sin_port), sizebuf);
	return (file);
}

/*
 * Tranfer the contents of "instr" to
 * "outstr" peer using the appropriate