SASL Client Example
The following code listing is for the sample client in SASL Example.
Note –
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 "@(#)client.c 1.4 03/04/07 SMI"
/* $Id: client.c,v 1.3 2002/09/03 15:11:59 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 <assert.h>
#include <sasl.h>
#include "common.h"
/* remove \r\n at end of the line */
static void chop(char *s)
{
char *p;
assert(s);
p = s + strlen(s) - 1;
if (p[0] == '\n') {
*p-- = '\0';
}
if (p >= s && p[0] == '\r') {
*p-- = '\0';
}
}
static int getrealm(void *context __attribute__((unused)),
int id,
const char **availrealms,
const char **result)
{
static char buf[1024];
/* Double-check the ID */
if (id != SASL_CB_GETREALM) return SASL_BADPARAM;
if (!result) return SASL_BADPARAM;
printf("please choose a realm (available:");
while (*availrealms) {
printf(" %s", *availrealms);
availrealms++;
}
printf("): ");
fgets(buf, sizeof buf, stdin);
chop(buf);
*result = buf;
return SASL_OK;
}
static int simple(void *context __attribute__((unused)),
int id,
const char **result,
unsigned *len)
{
static char buf[1024];
/* Double-check the connection */
if (! result)
return SASL_BADPARAM;
switch (id) {
case SASL_CB_USER:
printf("please enter an authorization id: ");
break;
case SASL_CB_AUTHNAME:
printf("please enter an authentication id: ");
break;
default:
return SASL_BADPARAM;
}
fgets(buf, sizeof buf, stdin);
chop(buf);
*result = buf;
if (len) *len = strlen(buf);
return SASL_OK;
}
#ifndef HAVE_GETPASSPHRASE
static char *
getpassphrase(const char *prompt)
{
return getpass(prompt);
}
#endif /* ! HAVE_GETPASSPHRASE */
static int
getsecret(sasl_conn_t *conn,
void *context __attribute__((unused)),
int id,
sasl_secret_t **psecret)
{
char *password;
size_t len;
static sasl_secret_t *x;
/* paranoia check */
if (! conn || ! psecret || id != SASL_CB_PASS)
return SASL_BADPARAM;
password = getpassphrase("Password: ");
if (! password)
return SASL_FAIL;
len = strlen(password);
x = (sasl_secret_t *) realloc(x, sizeof(sasl_secret_t) + len);
if (!x) {
memset(password, 0, len);
return SASL_NOMEM;
}
x->len = len;
#ifdef _SUN_SDK_
strcpy((char *)x->data, password);
#else
strcpy(x->data, password);
#endif /* _SUN_SDK_ */
memset(password, 0, len);
*psecret = x;
return SASL_OK;
}
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_GETREALM, &getrealm, NULL
}, {
SASL_CB_USER, &simple, NULL
}, {
SASL_CB_AUTHNAME, &simple, NULL
}, {
SASL_CB_PASS, &getsecret, NULL
}, {
SASL_CB_GETPATH, &getpath, NULL
}, {
SASL_CB_LIST_END, NULL, NULL
}
};
int getconn(const char *host, const char *port)
{
struct addrinfo hints, *ai, *r;
int err, sock = -1;
memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
if ((err = getaddrinfo(host, port, &hints, &ai)) != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(err));
exit(EX_UNAVAILABLE);
}
for (r = ai; r; r = r->ai_next) {
sock = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
if (sock < 0)
continue;
if (connect(sock, r->ai_addr, r->ai_addrlen) >= 0)
break;
close(sock);
sock = -1;
}
freeaddrinfo(ai);
if (sock < 0) {
perror("connect");
exit(EX_UNAVAILABLE);
}
return sock;
}
char *mech;
int mysasl_negotiate(FILE *in, FILE *out, sasl_conn_t *conn)
{
char buf[8192];
const char *data;
const char *chosenmech;
#ifdef _SUN_SDK_
unsigned len;
#else
int len;
#endif /* _SUN_SDK_ */
int r, c;
/* get the capability list */
dprintf(0, "receiving capability list... ");
len = recv_string(in, buf, sizeof buf);
dprintf(0, "%s\n", buf);
if (mech) {
/* make sure that 'mech' appears in 'buf' */
if (!strstr(buf, mech)) {
printf("server doesn't offer mandatory mech '%s'\n", mech);
return -1;
}
} else {
mech = buf;
}
r = sasl_client_start(conn, mech, NULL, &data, &len, &chosenmech);
if (r != SASL_OK && r != SASL_CONTINUE) {
saslerr(r, "starting SASL negotiation");
printf("\n%s\n", sasl_errdetail(conn));
return -1;
}
dprintf(1, "using mechanism %s\n", chosenmech);
/* we send up to 3 strings;
the mechanism chosen, the presence of initial response,
and optionally the initial response */
send_string(out, chosenmech, strlen(chosenmech));
if(data) {
send_string(out, "Y", 1);
send_string(out, data, len);
} else {
send_string(out, "N", 1);
}
for (;;) {
dprintf(2, "waiting for server reply...\n");
c = fgetc(in);
switch (c) {
case 'O':
goto done_ok;
case 'N':
goto done_no;
case 'C': /* continue authentication */
break;
default:
printf("bad protocol from server (%c %x)\n", c, c);
return -1;
}
len = recv_string(in, buf, sizeof buf);
r = sasl_client_step(conn, buf, len, NULL, &data, &len);
if (r != SASL_OK && r != SASL_CONTINUE) {
saslerr(r, "performing SASL negotiation");
printf("\n%s\n", sasl_errdetail(conn));
return -1;
}
if (data) {
dprintf(2, "sending response length %d...\n", len);
send_string(out, data, len);
} else {
dprintf(2, "sending null response...\n");
send_string(out, "", 0);
}
}
done_ok:
printf("successful authentication\n");
return 0;
done_no:
printf("authentication failed\n");
return -1;
}
#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] host\n", s);
#else
fprintf(stderr, "usage: client [-p port] [-s service] \
[-m mech] host\n");
#endif /* _SUN_SDK_ */
exit(EX_USAGE);
}
int main(int argc, char *argv[])
{
int c;
char *host = "localhost";
char *port = "12345";
char localaddr[NI_MAXHOST + NI_MAXSERV],
remoteaddr[NI_MAXHOST + NI_MAXSERV];
char *service = "rcmd";
char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV];
int r;
sasl_conn_t *conn;
FILE *in, *out;
int fd;
int salen;
struct sockaddr_storage local_ip, remote_ip;
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;
}
}
if (optind > argc - 1) {
#ifdef _SUN_SDK_
usage(argv[0]);
#else
usage();
#endif /* _SUN_SDK_ */
}
if (optind == argc - 1) {
host = argv[optind];
}
/* initialize the sasl library */
r = sasl_client_init(callbacks);
if (r != SASL_OK) saslfail(r, "initializing libsasl");
/* connect to remote server */
fd = getconn(host, port);
/* 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);
/* client new connection */
r = sasl_client_new(service, host, 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();
return 0;
}
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