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/*
* send_to_kdc.c
*
* Copyright 1987, 1988 by the Massachusetts Institute of Technology.
*
* For copying and distribution information, please see the file
* <mit-copyright.h>.
*/
#include "mit-copyright.h"
#define DEFINE_SOCKADDR /* Ask for sockets declarations from krb.h. */
#include "krb.h"
#include "krbports.h"
#include "prot.h"
#include <stdio.h>
#include <string.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#define S_AD_SZ sizeof(struct sockaddr_in)
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#else
extern char *malloc(), *calloc(), *realloc();
#endif
static int cached_krb_udp_port = 0;
static int cached_krbsec_udp_port = 0;
static int
send_recv PROTOTYPE ((KTEXT pkt, KTEXT rpkt, SOCKET f,
struct sockaddr_in *_to, struct hostent *addrs));
#ifdef DEBUG
static char *prog = "send_to_kdc";
#endif
/*
* send_to_kdc() sends a message to the Kerberos authentication
* server(s) in the given realm and returns the reply message.
* The "pkt" argument points to the message to be sent to Kerberos;
* the "rpkt" argument will be filled in with Kerberos' reply.
* The "realm" argument indicates the realm of the Kerberos server(s)
* to transact with. If the realm is null, the local realm is used.
*
* If more than one Kerberos server is known for a given realm,
* different servers will be queried until one of them replies.
* Several attempts (retries) are made for each server before
* giving up entirely.
*
* The following results can be returned:
*
* KSUCCESS - an answer was received from a Kerberos host
*
* SKDC_CANT - can't get local realm
* - can't find "kerberos" in /etc/services database
* - can't open socket
* - can't bind socket
* - all ports in use
* - couldn't find any Kerberos host
*
* SKDC_RETRY - couldn't get an answer from any Kerberos server,
* after several retries
*/
send_to_kdc(pkt,rpkt,realm)
KTEXT pkt;
KTEXT rpkt;
char *realm;
{
int i;
SOCKET f;
int no_host; /* was a kerberos host found? */
int retry;
int n_hosts;
int retval;
struct sockaddr_in to;
struct hostent FAR *farkedhost;
struct hostent *host, *hostlist;
char *cp;
char krbhst[MAXHOSTNAMELEN];
char lrealm[REALM_SZ];
char *scol;
int krb_udp_port = 0;
int krbsec_udp_port = 0;
int default_port;
/*
* If "realm" is non-null, use that, otherwise get the
* local realm.
*/
if (realm)
(void) strncpy(lrealm, realm, sizeof(lrealm) - 1);
else
if (krb_get_lrealm(lrealm,1)) {
DEB (("%s: can't get local realm\n", prog));
return(SKDC_CANT);
}
lrealm[sizeof(lrealm) - 1] = '\0';
DEB (("lrealm is %s\n", lrealm));
if (SOCKET_INITIALIZE()) {
DEB (("%s: can't initialize sockets library\n",prog));
return (SKDC_CANT);
}
/* from now on, exit through rtn label for cleanup */
/* The first time, decide what port to use for the KDC. */
if (cached_krb_udp_port == 0) {
register struct servent FAR *sp;
if (sp = getservbyname("kerberos","udp"))
cached_krb_udp_port = sp->s_port;
else
cached_krb_udp_port = htons(KERBEROS_PORT); /* kerberos/udp */
DEB (("cached_krb_udp_port is %d\n", cached_krb_udp_port));
}
/* If kerberos/udp isn't 750, try using kerberos-sec/udp (or 750)
as a fallback. */
if (cached_krbsec_udp_port == 0 &&
cached_krb_udp_port != htons(KERBEROS_PORT)) {
register struct servent FAR *sp;
if (sp = getservbyname("kerberos-sec","udp"))
cached_krbsec_udp_port = sp->s_port;
else
cached_krbsec_udp_port = htons(KERBEROS_PORT); /* kerberos/udp */
DEB (("cached_krbsec_udp_port is %d\n", cached_krbsec_udp_port));
}
memset((char *)&to, 0, S_AD_SZ);
hostlist = (struct hostent *) malloc(sizeof(struct hostent));
if (!hostlist) {
retval = /*errno */SKDC_CANT;
goto rtn_clean; /* Run SOCKET_CLEANUP then return. */
}
hostlist->h_name = 0; /* so it gets properly freed at "rtn" */
f = socket(AF_INET, SOCK_DGRAM, 0);
if (f == INVALID_SOCKET) {
DEB (("%s: Can't open socket\n", prog));
retval = /*errno */SKDC_CANT;
goto rtn_clean; /* Run SOCKET_CLEANUP then return. */
}
/*
** FIXME! FTP Software's WINSOCK implmentation insists that
** a socket be bound before it can receive datagrams.
** This is outside specs. Since it shouldn't hurt any
** other implementations we'll go ahead and do it for
** now.
*/
{
struct sockaddr_in from;
memset ((char *)&from, 0, S_AD_SZ);
from.sin_family = AF_INET;
from.sin_addr.s_addr = INADDR_ANY;
if ( bind(f, (struct sockaddr *)&from, S_AD_SZ) == SOCKET_ERROR ) {
DEB (("%s : Can't bind\n", prog));
retval = SKDC_CANT;
goto rtn;
}
}
/* End of kludge (FIXME) for FTP Software WinSock stack. */
no_host = 1;
default_port = 0;
/* get an initial allocation */
n_hosts = 0;
for (i = 1; krb_get_krbhst(krbhst, lrealm, i) == KSUCCESS; ++i) {
#ifdef DEBUG
if (krb_debug) {
DEB (("Getting host entry for %s...",krbhst));
(void) fflush(stdout);
}
#endif
if (0 != (scol = strchr(krbhst,':'))) {
krb_udp_port = htons(atoi(scol+1));
*scol = 0;
if (krb_udp_port == 0) {
#ifdef DEBUG
if (krb_debug) {
DEB (("bad port number %s\n",scol+1));
(void) fflush(stdout);
}
#endif
continue;
}
krbsec_udp_port = 0;
} else {
krb_udp_port = cached_krb_udp_port;
krbsec_udp_port = cached_krbsec_udp_port;
default_port = 1;
}
farkedhost = gethostbyname(krbhst);
#ifdef DEBUG
if (krb_debug) {
DEB (("%s.\n", farkedhost ? "Got it" : "Didn't get it"));
(void) fflush(stdout);
}
#endif
if (!farkedhost)
continue;
no_host = 0; /* found at least one */
n_hosts++;
/* preserve host network address to check later
* (would be better to preserve *all* addresses,
* take care of that later)
*/
hostlist = (struct hostent *)
realloc((char *)hostlist,
(unsigned)
sizeof(struct hostent)*(n_hosts+1));
if (!hostlist) {
retval = /*errno */SKDC_CANT;
goto rtn;
}
hostlist[n_hosts-1] = *farkedhost; /* Copy into array */
memset((char *)&hostlist[n_hosts], 0, sizeof(struct hostent));
host = &hostlist[n_hosts-1];
cp = malloc((unsigned)host->h_length);
if (!cp) {
retval = /*errno */SKDC_CANT;
goto rtn;
}
memcpy(cp, host->h_addr, host->h_length);
/* At least Sun OS version 3.2 (or worse) and Ultrix version 2.2
(or worse) only return one name ... */
#if !(defined(ULTRIX022) || (defined(SunOS) && SunOS < 40))
host->h_addr_list = (char **)malloc(sizeof(char *));
if (!host->h_addr_list) {
retval = /*errno */SKDC_CANT;
goto rtn;
}
#endif /* ULTRIX022 || SunOS */
host->h_addr = cp;
to.sin_family = host->h_addrtype;
memcpy((char *)&to.sin_addr, host->h_addr,
host->h_length);
to.sin_port = krb_udp_port;
if (send_recv(pkt, rpkt, f, &to, hostlist)) {
retval = KSUCCESS;
goto rtn;
}
if (krbsec_udp_port) {
to.sin_port = krbsec_udp_port;
if (send_recv(pkt, rpkt, f, &to, hostlist)) {
retval = KSUCCESS;
goto rtn;
}
}
DEB (("Timeout, error, or wrong descriptor\n"));
}
if (no_host) {
DEB (("%s: can't find any Kerberos host.\n", prog));
retval = SKDC_CANT;
goto rtn;
}
/* retry each host in sequence */
for (retry = 0; retry < CLIENT_KRB_RETRY; ++retry) {
for (host = hostlist; host->h_name != (char *)NULL; host++) {
to.sin_family = host->h_addrtype;
memcpy((char *)&to.sin_addr, host->h_addr,
host->h_length);
if (send_recv(pkt, rpkt, f, &to, hostlist)) {
retval = KSUCCESS;
goto rtn;
}
}
}
retval = SKDC_RETRY;
rtn:
(void) closesocket (f);
rtn_clean:
SOCKET_CLEANUP(); /* Done with using sockets for awhile */
if (hostlist) {
register struct hostent *hp;
for (hp = hostlist; hp->h_name; hp++)
#if !(defined(ULTRIX022) || (defined(SunOS) && SunOS < 40))
if (hp->h_addr_list) {
#endif /* ULTRIX022 || SunOS */
if (hp->h_addr)
free(hp->h_addr);
#if !(defined(ULTRIX022) || (defined(SunOS) && SunOS < 40))
free((char *)hp->h_addr_list);
}
#endif /* ULTRIX022 || SunOS */
free((char *)hostlist);
}
return(retval);
}
/*
* try to send out and receive message.
* return 1 on success, 0 on failure
*/
static int
send_recv(pkt,rpkt,f,_to,addrs)
KTEXT pkt;
KTEXT rpkt;
SOCKET f;
struct sockaddr_in *_to;
struct hostent *addrs;
{
fd_set readfds;
register struct hostent *hp;
struct sockaddr_in from;
int sin_size;
int numsent;
int selresult;
int recvresult;
struct timeval timeout;
#ifdef DEBUG
if (krb_debug) {
if (_to->sin_family == AF_INET) {
printf("Sending message to ");
far_fputs (inet_ntoa(_to->sin_addr), stdout);
printf("...");
} else
printf("Sending message...");
(void) fflush(stdout);
}
#endif
if ((numsent = sendto(f,(char *)(pkt->dat), pkt->length, 0,
(struct sockaddr *)_to,
S_AD_SZ)) != pkt->length) {
DEB (("sent only %d/%d\n",numsent, pkt->length));
return 0;
}
#ifdef DEBUG
if (krb_debug) {
printf("Sent\nWaiting for reply...");
(void) fflush(stdout);
}
#endif
FD_ZERO(&readfds);
FD_SET(f, &readfds);
SOCKET_SET_ERRNO (0);
/* select - either recv is ready, or timeout */
/* see if timeout or error or wrong descriptor */
/* Need to fill in the timeout structure each time, because on some
systems -- e.g., Linux -- the timeout will be modified in place
by the select syscall. */
timeout.tv_sec = CLIENT_KRB_TIMEOUT;
timeout.tv_usec = 0;
selresult = select(SOCKET_NFDS(f), &readfds, (fd_set *)0, (fd_set *)0,
&timeout);
if (selresult != 1 || !FD_ISSET(f, &readfds)) {
#ifdef DEBUG
if (krb_debug) {
fprintf(stderr, "select failed: selresult=%d, readfds=%x, errno=%d",
selresult, readfds, SOCKET_ERRNO);
perror("");
}
#endif
return 0;
}
sin_size = sizeof(from);
recvresult = recvfrom(f, (char *)(rpkt->dat), sizeof(rpkt->dat), 0,
(struct sockaddr *)&from, &sin_size);
if (recvresult < 0) {
DEB (("Recvfrom error %d\n", SOCKET_ERRNO));
return 0;
}
#ifdef DEBUG
if (krb_debug) {
printf("received packet from ");
far_fputs (inet_ntoa(from.sin_addr), stdout);
printf("\n");
fflush(stdout);
}
#endif
for (hp = addrs; hp->h_name != (char *)NULL; hp++) {
if (!memcmp(hp->h_addr, (char *)&from.sin_addr.s_addr,
hp->h_length)) {
DEB (("Received it\n"));
return 1;
}
DEB (("packet not from %x\n", hp->h_addr));
}
DEB (("%s: received packet from wrong host! (%x)\n",
"send_to_kdc(send_rcv)", from.sin_addr.s_addr));
return 0;
}
|