kprop.c   [plain text]

/*
 * slave/kprop.c
 *
 * Copyright 1990,1991 by the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 * 
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 * 
 *
 */


#include <errno.h>
#include <stdio.h>
#include <ctype.h>
#include <sys/file.h>
#include <signal.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/param.h>
#include <netdb.h>
#include <fcntl.h>

#include "k5-int.h"
#include "com_err.h"
#include "kprop.h"

#ifndef GETSOCKNAME_ARG3_TYPE
#define GETSOCKNAME_ARG3_TYPE unsigned int
#endif

static char *kprop_version = KPROP_PROT_VERSION;

char	*progname = 0;
int     debug = 0;
char	*srvtab = 0;
char	*slave_host;
char	*realm = 0;
char	*file = KPROP_DEFAULT_FILE;
short	port = 0;

krb5_principal	my_principal;		/* The Kerberos principal we'll be */
				/* running under, initialized in */
				/* get_tickets() */
krb5_ccache	ccache;		/* Credentials cache which we'll be using */
krb5_creds	creds;
krb5_address	sender_addr;
krb5_address	receiver_addr;

void	PRS
	(int, char **);
void	get_tickets
	(krb5_context);
static void usage 
	(void);
krb5_error_code open_connection 
	(char *, int *, char *, unsigned int);
void	kerberos_authenticate 
	(krb5_context, krb5_auth_context *, 
		   int, krb5_principal, krb5_creds **);
int	open_database 
	(krb5_context, char *, int *);
void	close_database 
	(krb5_context, int);
void	xmit_database 
	(krb5_context, krb5_auth_context, krb5_creds *, 
		   int, int, int);
void	send_error 
	(krb5_context, krb5_creds *, int, char *, krb5_error_code);
void	update_last_prop_file 
	(char *, char *);

static void usage()
{
	fprintf(stderr, "\nUsage: %s [-r realm] [-f file] [-d] [-P port] [-s srvtab] slave_host\n\n",
		progname);
	exit(1);
}

int
main(argc, argv)
	int	argc;
	char	**argv;
{
	int	fd, database_fd, database_size;
	krb5_error_code	retval;
	krb5_context context;
	krb5_creds *my_creds;
	krb5_auth_context auth_context;
	char	Errmsg[256];
	
	retval = krb5_init_context(&context);
	if (retval) {
		com_err(argv[0], retval, "while initializing krb5");
		exit(1);
	}
	PRS(argc, argv);
	get_tickets(context);

	database_fd = open_database(context, file, &database_size);
	retval = open_connection(slave_host, &fd, Errmsg, sizeof(Errmsg));
	if (retval) {
		com_err(progname, retval, "%s while opening connection to %s",
			Errmsg, slave_host);
		exit(1);
	}
	if (fd < 0) {
		fprintf(stderr, "%s: %s while opening connection to %s\n",
			progname, Errmsg, slave_host);
		exit(1);
	}
	kerberos_authenticate(context, &auth_context, fd, my_principal, 
			      &my_creds);
	xmit_database(context, auth_context, my_creds, fd, database_fd, 
		      database_size);
	update_last_prop_file(slave_host, file);
	printf("Database propagation to %s: SUCCEEDED\n", slave_host);
	krb5_free_cred_contents(context, my_creds);
	close_database(context, database_fd);
	exit(0);
}

void PRS(argc, argv)
	int	argc;
	char	**argv;
{
	register char	*word, ch;
	
	progname = *argv++;
	while (--argc && (word = *argv++)) {
		if (*word == '-') {
			word++;
			while (word && (ch = *word++)) {
				switch(ch){
				case 'r':
					if (*word)
						realm = word;
					else
						realm = *argv++;
					if (!realm)
						usage();
					word = 0;
					break;
				case 'f':
					if (*word)
						file = word;
					else
						file = *argv++;
					if (!file)
						usage();
					word = 0;
					break;
				case 'd':
					debug++;
					break;
				case 'P':
					if (*word)
						port = htons(atoi(word));
					else
						port = htons(atoi(*argv++));
					if (!port)
						usage();
					word = 0;
					break;
				case 's':
					if (*word)
						srvtab = word;
					else
						srvtab = *argv++;
					if (!srvtab)
						usage();
					word = 0;
					break;
				default:
					usage();
				}
				
			}
		} else {
			if (slave_host)
				usage();
			else
				slave_host = word;
		}
	}
	if (!slave_host)
		usage();
}

void get_tickets(context)
    krb5_context context;
{
	char   buf[BUFSIZ];
	krb5_error_code retval;
	static char tkstring[] = "/tmp/kproptktXXXXXX";
	krb5_keytab keytab = NULL;

	/*
	 * Figure out what tickets we'll be using to send stuff
	 */
	retval = krb5_sname_to_principal(context, NULL, NULL,
					 KRB5_NT_SRV_HST, &my_principal);
	if (retval) {
	    com_err(progname, errno, "while setting client principal name");
	    exit(1);
	}
	if (realm) {
	    retval = krb5_set_principal_realm(context, my_principal, realm);
	    if (retval) {
	        com_err(progname, errno, 
			"while setting client principal realm");
		exit(1);
	    }
	}
#if 0
	krb5_princ_type(context, my_principal) = KRB5_NT_PRINCIPAL;
#endif

	/*
	 * Initialize cache file which we're going to be using
	 */
	(void) mktemp(tkstring);
	sprintf(buf, "FILE:%s", tkstring);

	retval = krb5_cc_resolve(context, buf, &ccache);
	if (retval) {
		com_err(progname, retval, "while opening credential cache %s",
			buf);
		exit(1);
	}

	retval = krb5_cc_initialize(context, ccache, my_principal);
	if (retval) {
		com_err (progname, retval, "when initializing cache %s",
			 buf);
		exit(1);
	}

	/*
	 * Get the tickets we'll need.
	 *
	 * Construct the principal name for the slave host.
	 */
	memset((char *)&creds, 0, sizeof(creds));
	retval = krb5_sname_to_principal(context,
					 slave_host, KPROP_SERVICE_NAME,
					 KRB5_NT_SRV_HST, &creds.server);
	if (retval) {
	    com_err(progname, errno, "while setting server principal name");
	    (void) krb5_cc_destroy(context, ccache);
	    exit(1);
	}
	if (realm) {
	    retval = krb5_set_principal_realm(context, creds.server, realm);
	    if (retval) {
	        com_err(progname, errno, 
			"while setting server principal realm");
		exit(1);
	    }
	}

	/*
	 * Now fill in the client....
	 */
	retval = krb5_copy_principal(context, my_principal, &creds.client);
	if (retval) {
		com_err(progname, retval, "While copying client principal");
		(void) krb5_cc_destroy(context, ccache);
		exit(1);
	}
	if (srvtab) {
	        retval = krb5_kt_resolve(context, srvtab, &keytab);
		if (retval) {
			com_err(progname, retval, "while resolving keytab");
			(void) krb5_cc_destroy(context, ccache);
			exit(1);
		}
	}

	retval = krb5_get_in_tkt_with_keytab(context, 0, 0, NULL,
					     NULL, keytab, ccache, &creds, 0);
	if (retval) {
		com_err(progname, retval, "while getting initial ticket\n");
		(void) krb5_cc_destroy(context, ccache);
		exit(1);
	}

	if (keytab)
	    (void) krb5_kt_close(context, keytab);
	
	/*
	 * Now destroy the cache right away --- the credentials we
	 * need will be in my_creds.
	 */
	retval = krb5_cc_destroy(context, ccache);
	if (retval) {
		com_err(progname, retval, "while destroying ticket cache");
		exit(1);
	}
}

krb5_error_code
open_connection(host, fd, Errmsg, ErrmsgSz)
	char		*host;
	int		*fd;
	char		*Errmsg;
	unsigned int	 ErrmsgSz;
{
	int	s;
	krb5_error_code	retval;
	
	struct hostent	*hp;
	register struct servent *sp;
	struct sockaddr_in my_sin;
	GETSOCKNAME_ARG3_TYPE socket_length;

	hp = gethostbyname(host);
	if (hp == NULL) {
		(void) sprintf(Errmsg, "%s: unknown host", host);
		*fd = -1;
		return(0);
	}
	my_sin.sin_family = hp->h_addrtype;
	memcpy((char *)&my_sin.sin_addr, hp->h_addr, sizeof(my_sin.sin_addr));
	if(!port) {
		sp = getservbyname(KPROP_SERVICE, "tcp");
		if (sp == 0) {
		    my_sin.sin_port = htons(KPROP_PORT);
		} else {
		    my_sin.sin_port = sp->s_port;
		}
	} else
		my_sin.sin_port = port;
	s = socket(AF_INET, SOCK_STREAM, 0);
	
	if (s < 0) {
		(void) sprintf(Errmsg, "in call to socket");
		return(errno);
	}
	if (connect(s, (struct sockaddr *)&my_sin, sizeof my_sin) < 0) {
		retval = errno;
		close(s);
		(void) sprintf(Errmsg, "in call to connect");
		return(retval);
	}
	*fd = s;

	/*
	 * Set receiver_addr and sender_addr.
	 */
	receiver_addr.addrtype = ADDRTYPE_INET;
	receiver_addr.length = sizeof(my_sin.sin_addr);
	receiver_addr.contents = (krb5_octet *) malloc(sizeof(my_sin.sin_addr));
	memcpy((char *) receiver_addr.contents, (char *) &my_sin.sin_addr,
	       sizeof(my_sin.sin_addr));

	socket_length = sizeof(my_sin);
	if (getsockname(s, (struct sockaddr *)&my_sin, &socket_length) < 0) {
		retval = errno;
		close(s);
		(void) sprintf(Errmsg, "in call to getsockname");
		return(retval);
	}
	sender_addr.addrtype = ADDRTYPE_INET;
	sender_addr.length = sizeof(my_sin.sin_addr);
	sender_addr.contents = (krb5_octet *) malloc(sizeof(my_sin.sin_addr));
	memcpy((char *) sender_addr.contents, (char *) &my_sin.sin_addr,
	       sizeof(my_sin.sin_addr));

	return(0);
}


void kerberos_authenticate(context, auth_context, fd, me, new_creds)
    krb5_context context;
    krb5_auth_context *auth_context;
    int	fd;
    krb5_principal me;
    krb5_creds ** new_creds;
{
	krb5_error_code	retval;
	krb5_error	*error = NULL;
	krb5_ap_rep_enc_part	*rep_result;

    retval = krb5_auth_con_init(context, auth_context);
    if (retval) 
	exit(1);

    krb5_auth_con_setflags(context, *auth_context, 
			   KRB5_AUTH_CONTEXT_DO_SEQUENCE);

    retval = krb5_auth_con_setaddrs(context, *auth_context, &sender_addr,
				    &receiver_addr);
    if (retval) {
	com_err(progname, retval, "in krb5_auth_con_setaddrs");
	exit(1);
    }

    retval = krb5_sendauth(context, auth_context, (void *)&fd, 
			   kprop_version, me, creds.server,
			   AP_OPTS_MUTUAL_REQUIRED, NULL, &creds, NULL,
			   &error, &rep_result, new_creds);
    if (retval) {
        com_err(progname, retval, "while authenticating to server");
	if (error) {
	    if (error->error == KRB_ERR_GENERIC) {
	        if (error->text.data)
		    fprintf(stderr,
			    "Generic remote error: %s\n",
			    error->text.data);
	    } else if (error->error) {
	        com_err(progname,
			(krb5_error_code) error->error + ERROR_TABLE_BASE_krb5,
			"signalled from server");
		if (error->text.data)
		    fprintf(stderr,
			    "Error text from server: %s\n",
			    error->text.data);
	    }
	    krb5_free_error(context, error);
	}
	exit(1);
    }
    krb5_free_ap_rep_enc_part(context, rep_result);
}

char * dbpathname;
/*
 * Open the Kerberos database dump file.  Takes care of locking it
 * and making sure that the .ok file is more recent that the database
 * dump file itself.
 *
 * Returns the file descriptor of the database dump file.  Also fills
 * in the size of the database file.
 */
int
open_database(context, data_fn, size)
    krb5_context context;
    char *data_fn;
    int	*size;
{
	int		fd;
	int		err;
	struct stat 	stbuf, stbuf_ok;
	char		*data_ok_fn;
	static char ok[] = ".dump_ok";

	dbpathname = strdup(data_fn);
	if (!dbpathname) {
 	    com_err(progname, ENOMEM, "allocating database file name '%s'",
 		    data_fn);
 	    exit(1);
 	}
	if ((fd = open(dbpathname, O_RDONLY)) < 0) {
		com_err(progname, errno, "while trying to open %s",
			dbpathname);
		exit(1);
	}

	err = krb5_lock_file(context, fd,
			     KRB5_LOCKMODE_SHARED|KRB5_LOCKMODE_DONTBLOCK);
	if (err == EAGAIN || err == EWOULDBLOCK || errno == EACCES) {
	    com_err(progname, 0, "database locked");
	    exit(1);
	} else if (err) {
	    com_err(progname, err, "while trying to lock '%s'", dbpathname);
	    exit(1);
	}	    
	if (fstat(fd, &stbuf)) {
		com_err(progname, errno, "while trying to stat %s",
			data_fn);
		exit(1);
	}
	if ((data_ok_fn = (char *) malloc(strlen(data_fn)+strlen(ok)+1))
	    == NULL) {
		com_err(progname, ENOMEM, "while trying to malloc data_ok_fn");
		exit(1);
	}
	strcpy(data_ok_fn, data_fn);
	strcat(data_ok_fn, ok);
	if (stat(data_ok_fn, &stbuf_ok)) {
		com_err(progname, errno, "while trying to stat %s",
			data_ok_fn);
		free(data_ok_fn);
		exit(1);
	}
	free(data_ok_fn);
	if (stbuf.st_mtime > stbuf_ok.st_mtime) {
		com_err(progname, 0, "'%s' more recent than '%s'.",
			data_fn, data_ok_fn);
		exit(1);
	}
	*size = stbuf.st_size;
	return(fd);
}

void
close_database(context, fd)
    krb5_context context;
    int fd;
{
    int err;
    err = krb5_lock_file(context, fd, KRB5_LOCKMODE_UNLOCK);
    if (err)
	com_err(progname, err, "while unlocking database '%s'", dbpathname);
    free(dbpathname);
    (void)close(fd);
    return;
}
  
/*
 * Now we send over the database.  We use the following protocol:
 * Send over a KRB_SAFE message with the size.  Then we send over the
 * database in blocks of KPROP_BLKSIZE, encrypted using KRB_PRIV.
 * Then we expect to see a KRB_SAFE message with the size sent back.
 * 
 * At any point in the protocol, we may send a KRB_ERROR message; this
 * will abort the entire operation.
 */
void
xmit_database(context, auth_context, my_creds, fd, database_fd, 
	      in_database_size)
    krb5_context context;
    krb5_auth_context auth_context;
    krb5_creds *my_creds;
    int	fd;
    int	database_fd;
    int	in_database_size;
{
	krb5_int32	sent_size, n;
	krb5_data	inbuf, outbuf;
	char		buf[KPROP_BUFSIZ];
	krb5_error_code	retval;
	krb5_error	*error;
	/* These must be 4 bytes */
	krb5_ui_4	database_size = in_database_size; 
	krb5_ui_4	send_size;

	/*
	 * Send over the size
	 */
	send_size = htonl(database_size);
	inbuf.data = (char *) &send_size;
	inbuf.length = sizeof(send_size); /* must be 4, really */
	/* KPROP_CKSUMTYPE */
	retval = krb5_mk_safe(context, auth_context, &inbuf, 
			      &outbuf, NULL);
	if (retval) {
		com_err(progname, retval, "while encoding database size");
		send_error(context, my_creds, fd, "while encoding database size", retval);
		exit(1);
	}

	retval = krb5_write_message(context, (void *) &fd, &outbuf);
	if (retval) {
		krb5_free_data_contents(context, &outbuf);
		com_err(progname, retval, "while sending database size");
		exit(1);
	}
	krb5_free_data_contents(context, &outbuf);
	/*
	 * Initialize the initial vector.
	 */
	retval = krb5_auth_con_initivector(context, auth_context);
	if (retval) {
	    send_error(context, my_creds, fd, 
		       "failed while initializing i_vector", retval);
	    com_err(progname, retval, "while allocating i_vector");
	    exit(1);
	}
 
	/*
	 * Send over the file, block by block....
	 */
	inbuf.data = buf;
	sent_size = 0;
	while ((n = read(database_fd, buf, sizeof(buf)))) {
		inbuf.length = n;
		retval = krb5_mk_priv(context, auth_context, &inbuf,
				      &outbuf, NULL);
		if (retval) {
			sprintf(buf,
				"while encoding database block starting at %d",
				sent_size);
			com_err(progname, retval, buf);
			send_error(context, my_creds, fd, buf, retval);
			exit(1);
		}

		retval = krb5_write_message(context, (void *)&fd,&outbuf);
		if (retval) {
			krb5_free_data_contents(context, &outbuf);
			com_err(progname, retval,
				"while sending database block starting at %d",
				sent_size);
			exit(1);
		}
		krb5_free_data_contents(context, &outbuf);
		sent_size += n;
		if (debug)
			printf("%d bytes sent.\n", sent_size);
	}
	if (sent_size != database_size) {
		com_err(progname, 0, "Premature EOF found for database file!");
		send_error(context, my_creds, fd,"Premature EOF found for database file!",
			   KRB5KRB_ERR_GENERIC);
		exit(1);
	}

	/*
	 * OK, we've sent the database; now let's wait for a success
	 * indication from the remote end.
	 */
	retval = krb5_read_message(context, (void *) &fd, &inbuf);
	if (retval) {
		com_err(progname, retval,
			"while reading response from server");
		exit(1);
	}
	/*
	 * If we got an error response back from the server, display
	 * the error message
	 */
	if (krb5_is_krb_error(&inbuf)) {
 	        retval = krb5_rd_error(context, &inbuf, &error);
		if (retval) {
			com_err(progname, retval,
				"while decoding error response from server");
			exit(1);
		}
		if (error->error == KRB_ERR_GENERIC) {
			if (error->text.data)
				fprintf(stderr,
					"Generic remote error: %s\n",
					error->text.data);
		} else if (error->error) {
			com_err(progname, 
				(krb5_error_code) error->error + 
				  ERROR_TABLE_BASE_krb5,
				"signalled from server");
			if (error->text.data)
				fprintf(stderr,
					"Error text from server: %s\n",
					error->text.data);
		}
		krb5_free_error(context, error);
		exit(1);
	}

	retval = krb5_rd_safe(context,auth_context,&inbuf,&outbuf,NULL);
	if (retval) {
		com_err(progname, retval,
			"while decoding final size packet from server");
		exit(1);
	}

	memcpy((char *)&send_size, outbuf.data, sizeof(send_size));
	send_size = ntohl(send_size);
	if (send_size != database_size) {
		com_err(progname, 0,
			"Kpropd sent database size %d, expecting %d",
			send_size, database_size);
		exit(1);
	}
	free(outbuf.data);
	free(inbuf.data);
}

void
send_error(context, my_creds, fd, err_text, err_code)
    krb5_context context;
    krb5_creds *my_creds;
    int	fd;
    char	*err_text;
    krb5_error_code	err_code;
{
	krb5_error	error;
	const char	*text;
	krb5_data	outbuf;

	memset((char *)&error, 0, sizeof(error));
	krb5_us_timeofday(context, &error.ctime, &error.cusec);
	error.server = my_creds->server;
	error.client = my_principal;
	error.error = err_code - ERROR_TABLE_BASE_krb5;
	if (error.error > 127)
		error.error = KRB_ERR_GENERIC;
	if (err_text)
		text = err_text;
	else
		text = error_message(err_code);
	error.text.length = strlen(text) + 1;
	error.text.data = malloc((unsigned int) error.text.length);
	if (error.text.data) {
		strcpy(error.text.data, text);
		if (!krb5_mk_error(context, &error, &outbuf)) {
			(void) krb5_write_message(context, (void *)&fd,&outbuf);
			krb5_free_data_contents(context, &outbuf);
		}
		free(error.text.data);
	}
}

void update_last_prop_file(hostname, file_name)
	char *hostname;
	char *file_name;
{
	/* handle slave locking/failure stuff */
	char *file_last_prop;
	int fd;
	static char last_prop[]=".last_prop";

	if ((file_last_prop = (char *)malloc(strlen(file_name) +
					     strlen(hostname) + 1 +
					     strlen(last_prop) + 1)) == NULL) {
		com_err(progname, ENOMEM,
			"while allocating filename for update_last_prop_file");
		return;
	}
	strcpy(file_last_prop, file_name);
	strcat(file_last_prop, ".");
	strcat(file_last_prop, hostname);
	strcat(file_last_prop, last_prop);
	if ((fd = THREEPARAMOPEN(file_last_prop, O_WRONLY|O_CREAT|O_TRUNC, 0600)) < 0) {
		com_err(progname, errno,
			"while creating 'last_prop' file, '%s'",
			file_last_prop);
		free(file_last_prop);
		return;
	}
	write(fd, "", 1);
	free(file_last_prop);
	close(fd);
	return;
}