SASL Server Example
The following code listing is for the sample server in SASL Example.
The source code for this example is also available through the Sun download center. See http://www.sun.com/download/products.xml?id=41912db5.
#pragma ident "@(#)server.c 1.3 03/04/07 SMI"
/* $Id: server.c,v 1.4 2002/10/07 05:04:05 rjs3 Exp $ */
/*
* Copyright (c) 2001 Carnegie Mellon University. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The name "Carnegie Mellon University" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For permission or any other legal
* details, please contact
* Office of Technology Transfer
* Carnegie Mellon University
* 5000 Forbes Avenue
* Pittsburgh, PA 15213-3890
* (412) 268-4387, fax: (412) 268-7395
* tech-transfer@andrew.cmu.edu
*
* 4. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by Computing Services
* at Carnegie Mellon University (http://www.cmu.edu/computing/)."
*
* CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
* THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
* FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#ifdef _SUN_SDK_
#include <sysexits.h>
#endif /* _SUN_SDK_ */
#include <sasl.h>
#include "common.h"
#if !defined(IPV6_BINDV6ONLY) && defined(IN6P_IPV6_V6ONLY)
#define IPV6_BINDV6ONLY IN6P_BINDV6ONLY
#endif
#if !defined(IPV6_V6ONLY) && defined(IPV6_BINDV6ONLY)
#define IPV6_V6ONLY IPV6_BINDV6ONLY
#endif
#ifndef IPV6_BINDV6ONLY
#undef IPV6_V6ONLY
#endif
static int getpath(void * context __attribute__((unused)),
const char **path)
{
*path = getenv("SASL_PATH");
if (*path == NULL)
*path = PLUGINDIR;
return SASL_OK;
}
/* callbacks we support */
static sasl_callback_t callbacks[] = {
{
SASL_CB_GETPATH, &getpath, NULL
}, {
SASL_CB_LIST_END, NULL, NULL
}
};
/* create a socket listening on port 'port' */
/* if af is PF_UNSPEC more than one socket might be returned */
/* the returned list is dynamically allocated, so caller needs to free it */
int *listensock(const char *port, const int af)
{
struct addrinfo hints, *ai, *r;
int err, maxs, *sock, *socks;
const int on = 1;
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_PASSIVE;
hints.ai_family = af;
hints.ai_socktype = SOCK_STREAM;
err = getaddrinfo(NULL, port, &hints, &ai);
if (err) {
fprintf(stderr, "%s\n", gai_strerror(err));
exit(EX_USAGE);
}
/* Count max number of sockets we can open */
for (maxs = 0, r = ai; r; r = r->ai_next, maxs++)
;
socks = malloc((maxs + 1) * sizeof(int));
if (!socks) {
fprintf(stderr, "couldn't allocate memory for sockets\n");
freeaddrinfo(ai);
exit(EX_OSERR);
}
socks[0] = 0; /* num of sockets counter at start of array */
sock = socks + 1;
for (r = ai; r; r = r->ai_next) {
fprintf(stderr, "trying %d, %d, %d\n",r->ai_family, r->ai_socktype,
r->ai_protocol);
*sock = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
if (*sock < 0) {
perror("socket");
continue;
}
if (setsockopt(*sock, SOL_SOCKET, SO_REUSEADDR,
(void *) &on, sizeof(on)) < 0) {
perror("setsockopt(SO_REUSEADDR)");
close(*sock);
continue;
}
#if defined(IPV6_V6ONLY) && !(defined(__FreeBSD__) && __FreeBSD__ < 3)
if (r->ai_family == AF_INET6) {
if (setsockopt(*sock, IPPROTO_IPV6, IPV6_BINDV6ONLY,
(void *) &on, sizeof(on)) < 0) {
perror("setsockopt (IPV6_BINDV6ONLY)");
close(*sock);
continue;
}
}
#endif
if (bind(*sock, r->ai_addr, r->ai_addrlen) < 0) {
perror("bind");
close(*sock);
continue;
}
if (listen(*sock, 5) < 0) {
perror("listen");
close(*sock);
continue;
}
socks[0]++;
sock++;
}
freeaddrinfo(ai);
if (socks[0] == 0) {
fprintf(stderr, "Couldn't bind to any socket\n");
free(socks);
exit(EX_OSERR);
}
return socks;
}
#ifdef _SUN_SDK_
void usage(const char *s)
#else
void usage(void)
#endif /* _SUN_SDK_ */
{
#ifdef _SUN_SDK_
fprintf(stderr, "usage: %s [-p port] [-s service] [-m mech]\n", s);
#else
fprintf(stderr, "usage: server [-p port] [-s service] [-m mech]\n");
#endif /* _SUN_SDK_ */
exit(EX_USAGE);
}
/* Globals are used here, but local variables are preferred */
char *mech;
/* do the sasl negotiation; return -1 if it fails */
int mysasl_negotiate(FILE *in, FILE *out, sasl_conn_t *conn)
{
char buf[8192];
char chosenmech[128];
const char *data;
#ifdef _SUN_SDK_
unsigned len;
#else
int len;
#endif /* _SUN_SDK_ */
int r = SASL_FAIL;
const char *userid;
/* generate the capability list */
if (mech) {
dprintf(2, "forcing use of mechanism %s\n", mech);
data = strdup(mech);
} else {
int count;
dprintf(1, "generating client mechanism list... ");
r = sasl_listmech(conn, NULL, NULL, " ", NULL,
&data, &len, &count);
if (r != SASL_OK) saslfail(r, "generating mechanism list");
dprintf(1, "%d mechanisms\n", count);
}
/* send capability list to client */
send_string(out, data, len);
dprintf(1, "waiting for client mechanism...\n");
len = recv_string(in, chosenmech, sizeof chosenmech);
if (len <= 0) {
printf("client didn't choose mechanism\n");
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
if (mech && strcasecmp(mech, chosenmech)) {
printf("client didn't choose mandatory mechanism\n");
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
len = recv_string(in, buf, sizeof(buf));
if(len != 1) {
saslerr(r, "didn't receive first-send parameter correctly");
fputc('N', out);
fflush(out);
return -1;
}
if(buf[0] == 'Y') {
/* receive initial response (if any) */
len = recv_string(in, buf, sizeof(buf));
/* start libsasl negotiation */
r = sasl_server_start(conn, chosenmech, buf, len,
&data, &len);
} else {
r = sasl_server_start(conn, chosenmech, NULL, 0,
&data, &len);
}
if (r != SASL_OK && r != SASL_CONTINUE) {
saslerr(r, "starting SASL negotiation");
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
while (r == SASL_CONTINUE) {
if (data) {
dprintf(2, "sending response length %d...\n", len);
fputc('C', out); /* send CONTINUE to client */
send_string(out, data, len);
} else {
dprintf(2, "sending null response...\n");
fputc('C', out); /* send CONTINUE to client */
send_string(out, "", 0);
}
dprintf(1, "waiting for client reply...\n");
len = recv_string(in, buf, sizeof buf);
if (len < 0) {
printf("client disconnected\n");
return -1;
}
r = sasl_server_step(conn, buf, len, &data, &len);
if (r != SASL_OK && r != SASL_CONTINUE) {
saslerr(r, "performing SASL negotiation");
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
}
if (r != SASL_OK) {
saslerr(r, "incorrect authentication");
fputc('N', out); /* send NO to client */
fflush(out);
return -1;
}
fputc('O', out); /* send OK to client */
fflush(out);
dprintf(1, "negotiation complete\n");
r = sasl_getprop(conn, SASL_USERNAME, (const void **) &userid);
printf("successful authentication '%s'\n", userid);
return 0;
}
int main(int argc, char *argv[])
{
int c;
char *port = "12345";
char *service = "rcmd";
int *l, maxfd=0;
int r, i;
sasl_conn_t *conn;
while ((c = getopt(argc, argv, "p:s:m:")) != EOF) {
switch(c) {
case 'p':
port = optarg;
break;
case 's':
service = optarg;
break;
case 'm':
mech = optarg;
break;
default:
#ifdef _SUN_SDK_
usage(argv[0]);
#else
usage();
#endif /* _SUN_SDK_ */
break;
}
}
/* initialize the sasl library */
r = sasl_server_init(callbacks, "sample");
if (r != SASL_OK) saslfail(r, "initializing libsasl");
/* get a listening socket */
if ((l = listensock(port, PF_UNSPEC)) == NULL) {
saslfail(SASL_FAIL, "allocating listensock");
}
for (i = 1; i <= l[0]; i++) {
if (l[i] > maxfd)
maxfd = l[i];
}
for (;;) {
char localaddr[NI_MAXHOST | NI_MAXSERV],
remoteaddr[NI_MAXHOST | NI_MAXSERV];
char myhostname[1024+1];
char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV];
struct sockaddr_storage local_ip, remote_ip;
int salen;
int nfds, fd = -1;
FILE *in, *out;
fd_set readfds;
FD_ZERO(&readfds);
for (i = 1; i <= l[0]; i++)
FD_SET(l[i], &readfds);
nfds = select(maxfd + 1, &readfds, 0, 0, 0);
if (nfds <= 0) {
if (nfds < 0 && errno != EINTR)
perror("select");
continue;
}
for (i = 1; i <= l[0]; i++)
if (FD_ISSET(l[i], &readfds)) {
fd = accept(l[i], NULL, NULL);
break;
}
if (fd < 0) {
if (errno != EINTR)
perror("accept");
continue;
}
printf("accepted new connection\n");
/* set ip addresses */
salen = sizeof(local_ip);
if (getsockname(fd, (struct sockaddr *)&local_ip, &salen) < 0) {
perror("getsockname");
}
getnameinfo((struct sockaddr *)&local_ip, salen,
hbuf, sizeof(hbuf), pbuf, sizeof(pbuf),
#ifdef _SUN_SDK_ /* SOLARIS doesn't support NI_WITHSCOPEID */
NI_NUMERICHOST | NI_NUMERICSERV);
#else
NI_NUMERICHOST | NI_WITHSCOPEID | NI_NUMERICSERV);
#endif
snprintf(localaddr, sizeof(localaddr), "%s;%s", hbuf, pbuf);
salen = sizeof(remote_ip);
if (getpeername(fd, (struct sockaddr *)&remote_ip, &salen) < 0) {
perror("getpeername");
}
getnameinfo((struct sockaddr *)&remote_ip, salen,
hbuf, sizeof(hbuf), pbuf, sizeof(pbuf),
#ifdef _SUN_SDK_ /* SOLARIS doesn't support NI_WITHSCOPEID */
NI_NUMERICHOST | NI_NUMERICSERV);
#else
NI_NUMERICHOST | NI_WITHSCOPEID | NI_NUMERICSERV);
#endif
snprintf(remoteaddr, sizeof(remoteaddr), "%s;%s", hbuf, pbuf);
r = gethostname(myhostname, sizeof(myhostname)-1);
if(r == -1) saslfail(r, "getting hostname");
r = sasl_server_new(service, myhostname, NULL, localaddr, remoteaddr,
NULL, 0, &conn);
if (r != SASL_OK) saslfail(r, "allocating connection state");
/* set external properties here
sasl_setprop(conn, SASL_SSF_EXTERNAL, &extprops); */
/* set required security properties here
sasl_setprop(conn, SASL_SEC_PROPS, &secprops); */
in = fdopen(fd, "r");
out = fdopen(fd, "w");
r = mysasl_negotiate(in, out, conn);
if (r == SASL_OK) {
/* send/receive data */
}
printf("closing connection\n");
fclose(in);
fclose(out);
close(fd);
sasl_dispose(&conn);
}
sasl_done();
}
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