OpenBSD-4.6/libexec/login_radius/raddauth.c
/* $OpenBSD: raddauth.c,v 1.23 2007/12/14 14:23:25 millert Exp $ */
/*-
* Copyright (c) 1996, 1997 Berkeley Software Design, Inc. 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Berkeley Software Design,
* Inc.
* 4. The name of Berkeley Software Design, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN, INC. ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN, INC. BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* BSDI $From: raddauth.c,v 1.6 1998/04/14 00:39:04 prb Exp $
*/
/*
* Copyright(c) 1996 by tfm associates.
* All rights reserved.
*
* tfm associates
* P.O. Box 2086
* Eugene OR 97402-0031
*
* 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 of tfm associates may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY TFM ASSOC``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL TFM ASSOCIATES BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <login_cap.h>
#include <netdb.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>
#include <md5.h>
#include "login_radius.h"
#define MAXPWNETNAM 64 /* longest username */
#define MAXSECRETLEN 128 /* maximum length of secret */
#define AUTH_VECTOR_LEN 16
#define AUTH_HDR_LEN 20
#define AUTH_PASS_LEN (256 - 16)
#define PW_AUTHENTICATION_REQUEST 1
#define PW_AUTHENTICATION_ACK 2
#define PW_AUTHENTICATION_REJECT 3
#define PW_ACCESS_CHALLENGE 11
#define PW_USER_NAME 1
#define PW_PASSWORD 2
#define PW_CLIENT_ID 4
#define PW_CLIENT_PORT_ID 5
#define PW_PORT_MESSAGE 18
#define PW_STATE 24
#ifndef RADIUS_DIR
#define RADIUS_DIR "/etc/raddb"
#endif
#define RADIUS_SERVERS "servers"
char *radius_dir = RADIUS_DIR;
char auth_secret[MAXSECRETLEN+1];
volatile sig_atomic_t timedout;
int alt_retries;
int retries;
int sockfd;
int timeout;
in_addr_t alt_server;
in_addr_t auth_server;
in_port_t radius_port;
typedef struct {
u_char code;
u_char id;
u_short length;
u_char vector[AUTH_VECTOR_LEN];
u_char data[4096 - AUTH_HDR_LEN];
} auth_hdr_t;
void servtimeout(int);
in_addr_t get_ipaddr(char *);
in_addr_t gethost(void);
int rad_recv(char *, char *, u_char *);
void parse_challenge(auth_hdr_t *, char *, char *);
void rad_request(u_char, char *, char *, int, char *, char *);
void getsecret(void);
/*
* challenge -- NULL for interactive service
* password -- NULL for interactive service and when requesting a challenge
*/
int
raddauth(char *username, char *class, char *style, char *challenge,
char *password, char **emsg)
{
static char _pwstate[1024];
u_char req_id;
char *userstyle, *passwd, *pwstate, *rad_service;
int auth_port;
char vector[AUTH_VECTOR_LEN+1], *p, *v;
int i;
login_cap_t *lc;
u_int32_t r;
struct servent *svp;
struct sockaddr_in sin;
struct sigaction sa;
const char *errstr;
memset(_pwstate, 0, sizeof(_pwstate));
pwstate = password ? challenge : _pwstate;
if ((lc = login_getclass(class)) == NULL) {
snprintf(_pwstate, sizeof(_pwstate),
"%s: no such class", class);
*emsg = _pwstate;
return (1);
}
rad_service = login_getcapstr(lc, "radius-port", "radius", "radius");
timeout = login_getcapnum(lc, "radius-timeout", 2, 2);
retries = login_getcapnum(lc, "radius-retries", 6, 6);
if (timeout < 1)
timeout = 1;
if (retries < 2)
retries = 2;
if (challenge == NULL) {
passwd = NULL;
v = login_getcapstr(lc, "radius-challenge-styles",
NULL, NULL);
i = strlen(style);
while (v && (p = strstr(v, style)) != NULL) {
if ((p == v || p[-1] == ',') &&
(p[i] == ',' || p[i] == '\0')) {
passwd = "";
break;
}
v = p+1;
}
if (passwd == NULL)
passwd = getpass("Password:");
} else
passwd = password;
if (passwd == NULL)
passwd = "";
if ((v = login_getcapstr(lc, "radius-server", NULL, NULL)) == NULL){
*emsg = "radius-server not configured";
return (1);
}
auth_server = get_ipaddr(v);
if ((v = login_getcapstr(lc, "radius-server-alt", NULL, NULL)) == NULL)
alt_server = 0;
else {
alt_server = get_ipaddr(v);
alt_retries = retries/2;
retries >>= 1;
}
/* get port number */
radius_port = strtonum(rad_service, 1, UINT16_MAX, &errstr);
if (errstr) {
svp = getservbyname(rad_service, "udp");
if (svp == NULL) {
snprintf(_pwstate, sizeof(_pwstate),
"No such service: %s/udp", rad_service);
*emsg = _pwstate;
return (1);
}
radius_port = svp->s_port;
} else
radius_port = htons(radius_port);
/* get the secret from the servers file */
getsecret();
/* set up socket */
if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
snprintf(_pwstate, sizeof(_pwstate), "%s", strerror(errno));
*emsg = _pwstate;
return (1);
}
/* set up client structure */
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
sin.sin_port = radius_port;
req_id = (u_char) arc4random();
auth_port = ttyslot();
if (auth_port == 0)
auth_port = (int)getppid();
if (strcmp(style, "radius") != 0) {
if (asprintf(&userstyle, "%s:%s", username, style) == -1)
err(1, NULL);
} else
userstyle = username;
/* generate random vector */
for (i = 0; i < AUTH_VECTOR_LEN;) {
r = arc4random();
memcpy(&vector[i], &r, sizeof(r));
i += sizeof(r);
}
vector[AUTH_VECTOR_LEN] = '\0';
sigemptyset(&sa.sa_mask);
sa.sa_handler = servtimeout;
sa.sa_flags = 0; /* don't restart system calls */
(void)sigaction(SIGALRM, &sa, NULL);
retry:
if (timedout) {
timedout = 0;
if (--retries <= 0) {
/*
* If we ran out of tries but there is an alternate
* server, switch to it and try again.
*/
if (alt_retries) {
auth_server = alt_server;
retries = alt_retries;
alt_retries = 0;
getsecret();
} else
warnx("no response from authentication server");
}
}
if (retries > 0) {
rad_request(req_id, userstyle, passwd, auth_port, vector,
pwstate);
switch (i = rad_recv(_pwstate, challenge, vector)) {
case PW_AUTHENTICATION_ACK:
/*
* Make sure we don't think a challenge was issued.
*/
if (challenge)
*challenge = '\0';
return (0);
case PW_AUTHENTICATION_REJECT:
return (1);
case PW_ACCESS_CHALLENGE:
/*
* If this is a response then reject them if
* we got a challenge.
*/
if (password)
return (1);
/*
* If we wanted a challenge, just return
*/
if (challenge) {
if (strcmp(challenge, _pwstate) != 0)
syslog(LOG_WARNING,
"challenge for %s does not match state",
userstyle);
return (0);
}
req_id++;
if ((passwd = getpass("")) == NULL)
passwd = "";
break;
default:
if (timedout)
goto retry;
snprintf(_pwstate, sizeof(_pwstate),
"invalid response type %d\n", i);
*emsg = _pwstate;
return (1);
}
}
return (1);
}
/*
* Build a radius authentication digest and submit it to the radius server
*/
void
rad_request(u_char id, char *name, char *password, int port, char *vector,
char *state)
{
auth_hdr_t auth;
int i, len, secretlen, total_length, p;
struct sockaddr_in sin;
u_char md5buf[MAXSECRETLEN+AUTH_VECTOR_LEN], digest[AUTH_VECTOR_LEN],
pass_buf[AUTH_PASS_LEN], *pw, *ptr;
u_int length;
in_addr_t ipaddr;
MD5_CTX context;
memset(&auth, 0, sizeof(auth));
auth.code = PW_AUTHENTICATION_REQUEST;
auth.id = id;
memcpy(auth.vector, vector, AUTH_VECTOR_LEN);
total_length = AUTH_HDR_LEN;
ptr = auth.data;
/* User name */
*ptr++ = PW_USER_NAME;
length = strlen(name);
if (length > MAXPWNETNAM)
length = MAXPWNETNAM;
*ptr++ = length + 2;
memcpy(ptr, name, length);
ptr += length;
total_length += length + 2;
/* Password */
length = strlen(password);
if (length > AUTH_PASS_LEN)
length = AUTH_PASS_LEN;
p = (length + AUTH_VECTOR_LEN - 1) / AUTH_VECTOR_LEN;
*ptr++ = PW_PASSWORD;
*ptr++ = p * AUTH_VECTOR_LEN + 2;
memset(pass_buf, 0, sizeof(pass_buf)); /* must zero fill */
strlcpy((char *)pass_buf, password, sizeof(pass_buf));
/* Calculate the md5 digest */
secretlen = strlen(auth_secret);
memcpy(md5buf, auth_secret, secretlen);
memcpy(md5buf + secretlen, auth.vector, AUTH_VECTOR_LEN);
total_length += 2;
/* XOR the password into the md5 digest */
pw = pass_buf;
while (p-- > 0) {
MD5Init(&context);
MD5Update(&context, md5buf, secretlen + AUTH_VECTOR_LEN);
MD5Final(digest, &context);
for (i = 0; i < AUTH_VECTOR_LEN; ++i) {
*ptr = digest[i] ^ *pw;
md5buf[secretlen+i] = *ptr++;
*pw++ = '\0';
}
total_length += AUTH_VECTOR_LEN;
}
/* Client id */
*ptr++ = PW_CLIENT_ID;
*ptr++ = sizeof(in_addr_t) + 2;
ipaddr = gethost();
memcpy(ptr, &ipaddr, sizeof(in_addr_t));
ptr += sizeof(in_addr_t);
total_length += sizeof(in_addr_t) + 2;
/* client port */
*ptr++ = PW_CLIENT_PORT_ID;
*ptr++ = sizeof(in_addr_t) + 2;
port = htonl(port);
memcpy(ptr, &port, sizeof(int));
ptr += sizeof(int);
total_length += sizeof(int) + 2;
/* Append the state info */
if ((state != NULL) && (strlen(state) > 0)) {
len = strlen(state);
*ptr++ = PW_STATE;
*ptr++ = len + 2;
memcpy(ptr, state, len);
ptr += len;
total_length += len + 2;
}
auth.length = htons(total_length);
memset(&sin, 0, sizeof (sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = auth_server;
sin.sin_port = radius_port;
if (sendto(sockfd, &auth, total_length, 0, (struct sockaddr *)&sin,
sizeof(sin)) == -1)
err(1, NULL);
}
/*
* Receive UDP responses from the radius server
*/
int
rad_recv(char *state, char *challenge, u_char *req_vector)
{
auth_hdr_t auth;
socklen_t salen;
struct sockaddr_in sin;
u_char recv_vector[AUTH_VECTOR_LEN], test_vector[AUTH_VECTOR_LEN];
MD5_CTX context;
salen = sizeof(sin);
alarm(timeout);
if ((recvfrom(sockfd, &auth, sizeof(auth), 0,
(struct sockaddr *)&sin, &salen)) < AUTH_HDR_LEN) {
if (timedout)
return(-1);
errx(1, "bogus auth packet from server");
}
alarm(0);
if (sin.sin_addr.s_addr != auth_server)
errx(1, "bogus authentication server");
/* verify server's shared secret */
memcpy(recv_vector, auth.vector, AUTH_VECTOR_LEN);
memcpy(auth.vector, req_vector, AUTH_VECTOR_LEN);
MD5Init(&context);
MD5Update(&context, (u_char *)&auth, ntohs(auth.length));
MD5Update(&context, auth_secret, strlen(auth_secret));
MD5Final(test_vector, &context);
if (memcmp(recv_vector, test_vector, AUTH_VECTOR_LEN) != 0)
errx(1, "shared secret incorrect");
if (auth.code == PW_ACCESS_CHALLENGE)
parse_challenge(&auth, state, challenge);
return (auth.code);
}
/*
* Get IP address of local hostname
*/
in_addr_t
gethost(void)
{
char hostname[MAXHOSTNAMELEN];
if (gethostname(hostname, sizeof(hostname)))
err(1, "gethost");
return (get_ipaddr(hostname));
}
/*
* Get an IP address in host in_addr_t notation from a hostname or dotted quad.
*/
in_addr_t
get_ipaddr(char *host)
{
struct hostent *hp;
if ((hp = gethostbyname(host)) == NULL)
return (0);
return (((struct in_addr *)hp->h_addr)->s_addr);
}
/*
* Get the secret from the servers file
*/
void
getsecret(void)
{
FILE *servfd;
char *host, *secret, buffer[MAXPATHLEN];
size_t len;
snprintf(buffer, sizeof(buffer), "%s/%s",
radius_dir, RADIUS_SERVERS);
if ((servfd = fopen(buffer, "r")) == NULL) {
syslog(LOG_ERR, "%s: %m", buffer);
return;
}
secret = NULL; /* Keeps gcc happy */
while ((host = fgetln(servfd, &len)) != NULL) {
if (*host == '#') {
memset(host, 0, len);
continue;
}
if (host[len-1] == '\n')
--len;
else {
/* No trailing newline, must allocate len+1 for NUL */
if ((secret = malloc(len + 1)) == NULL) {
memset(host, 0, len);
continue;
}
memcpy(secret, host, len);
memset(host, 0, len);
host = secret;
}
while (len > 0 && isspace(host[--len]))
;
host[++len] = '\0';
while (isspace(*host)) {
++host;
--len;
}
if (*host == '\0')
continue;
secret = host;
while (*secret && !isspace(*secret))
++secret;
if (*secret)
*secret++ = '\0';
if (get_ipaddr(host) != auth_server) {
memset(host, 0, len);
continue;
}
while (isspace(*secret))
++secret;
if (*secret)
break;
}
if (host) {
strlcpy(auth_secret, secret, sizeof(auth_secret));
memset(host, 0, len);
}
fclose(servfd);
}
void
servtimeout(int signo)
{
timedout = 1;
}
/*
* Parse a challenge received from the server
*/
void
parse_challenge(auth_hdr_t *authhdr, char *state, char *challenge)
{
int length;
int attribute, attribute_len;
u_char *ptr;
ptr = authhdr->data;
length = ntohs(authhdr->length) - AUTH_HDR_LEN;
*state = 0;
while (length > 0) {
attribute = *ptr++;
attribute_len = *ptr++;
length -= attribute_len;
attribute_len -= 2;
switch (attribute) {
case PW_PORT_MESSAGE:
if (challenge) {
memcpy(challenge, ptr, attribute_len);
challenge[attribute_len] = '\0';
} else
printf("%.*s", attribute_len, ptr);
break;
case PW_STATE:
memcpy(state, ptr, attribute_len);
state[attribute_len] = '\0';
break;
}
ptr += attribute_len;
}
}