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Allow WPA passphrase to be fetched with RADIUS Tunnel-Password attribute

Browse source 
This allows per-device PSK to be configured for WPA-Personal using a
RADIUS authentication server. This uses RADIUS-based MAC address ACL
(macaddr_acl=2), i.e., Access-Request uses the MAC address of the
station as the User-Name and User-Password. The WPA passphrase is
returned in Tunnel-Password attribute in Access-Accept. This
functionality can be enabled with the new hostapd.conf parameter,
wpa_psk_radius.

Signed-hostap: Michael Braun <michael-dev@fami-braun.de>
This commit is contained in:
Michael Braun 2011-12-11 13:01:57 +02:00 committed by Jouni Malinen
parent c3daaf3325
commit 05ab9712b9
11 changed files with 224 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

21
hostapd/config_file.c
View file

@ -1050,9 +1050,18 @@ static int hostapd_config_check_bss(struct hostapd_bss_config *bss,
return -1;
}
if (bss->wpa && bss->wpa_psk_radius != PSK_RADIUS_IGNORED &&
bss->macaddr_acl != USE_EXTERNAL_RADIUS_AUTH) {
wpa_printf(MSG_ERROR, "WPA-PSK using RADIUS enabled, but no "
"RADIUS checking (macaddr_acl=2) enabled.");
return -1;
}
if (bss->wpa && (bss->wpa_key_mgmt & WPA_KEY_MGMT_PSK) &&
bss->ssid.wpa_psk == NULL && bss->ssid.wpa_passphrase == NULL &&
bss->ssid.wpa_psk_file == NULL) {
bss->ssid.wpa_psk_file == NULL &&
(bss->wpa_psk_radius != PSK_RADIUS_REQUIRED ||
bss->macaddr_acl != USE_EXTERNAL_RADIUS_AUTH)) {
wpa_printf(MSG_ERROR, "WPA-PSK enabled, but PSK or passphrase "
"is not configured.");
return -1;
@ -1629,6 +1638,16 @@ struct hostapd_config * hostapd_config_read(const char *fname)
hostapd_config_parse_key_mgmt(line, pos);
if (bss->wpa_key_mgmt == -1)
errors++;
} else if (os_strcmp(buf, "wpa_psk_radius") == 0) {
bss->wpa_psk_radius = atoi(pos);
if (bss->wpa_psk_radius != PSK_RADIUS_IGNORED &&
bss->wpa_psk_radius != PSK_RADIUS_ACCEPTED &&
bss->wpa_psk_radius != PSK_RADIUS_REQUIRED) {
wpa_printf(MSG_ERROR, "Line %d: unknown "
"wpa_psk_radius %d",
line, bss->wpa_psk_radius);
errors++;
}
} else if (os_strcmp(buf, "wpa_pairwise") == 0) {
bss->wpa_pairwise =
hostapd_config_parse_cipher(line, pos);

10
hostapd/hostapd.conf
View file

@ -676,6 +676,7 @@ own_ip_addr=127.0.0.1
# Enable WPA. Setting this variable configures the AP to require WPA (either
# WPA-PSK or WPA-RADIUS/EAP based on other configuration). For WPA-PSK, either
# wpa_psk or wpa_passphrase must be set and wpa_key_mgmt must include WPA-PSK.
# Instead of wpa_psk / wpa_passphrase, wpa_psk_radius might suffice.
# For WPA-RADIUS/EAP, ieee8021x must be set (but without dynamic WEP keys),
# RADIUS authentication server must be configured, and WPA-EAP must be included
# in wpa_key_mgmt.
@ -700,6 +701,15 @@ own_ip_addr=127.0.0.1
# configuration reloads.
#wpa_psk_file=/etc/hostapd.wpa_psk
# Optionally, WPA passphrase can be received from RADIUS authentication server
# This requires macaddr_acl to be set to 2 (RADIUS)
# 0 = disabled (default)
# 1 = optional; use default passphrase/psk if RADIUS server does not include
# Tunnel-Password
# 2 = required; reject authentication if RADIUS server does not include
# Tunnel-Password
#wpa_psk_radius=0
# Set of accepted key management algorithms (WPA-PSK, WPA-EAP, or both). The
# entries are separated with a space. WPA-PSK-SHA256 and WPA-EAP-SHA256 can be
# added to enable SHA256-based stronger algorithms.

5
src/ap/ap_config.h
View file

@ -219,6 +219,11 @@ struct hostapd_bss_config {
/* dot11AssociationSAQueryRetryTimeout (in TUs) */
int assoc_sa_query_retry_timeout;
#endif /* CONFIG_IEEE80211W */
enum {
PSK_RADIUS_IGNORED = 0,
PSK_RADIUS_ACCEPTED = 1,
PSK_RADIUS_REQUIRED = 2
} wpa_psk_radius;
int wpa_pairwise;
int wpa_group;
int wpa_group_rekey;

16
src/ap/ieee802_11.c
View file

@ -313,6 +313,8 @@ static void handle_auth(struct hostapd_data *hapd,
const u8 *challenge = NULL;
u32 session_timeout, acct_interim_interval;
int vlan_id = 0;
u8 psk[PMK_LEN];
int has_psk = 0;
u8 resp_ies[2 + WLAN_AUTH_CHALLENGE_LEN];
size_t resp_ies_len = 0;
@ -375,7 +377,9 @@ static void handle_auth(struct hostapd_data *hapd,
res = hostapd_allowed_address(hapd, mgmt->sa, (u8 *) mgmt, len,
&session_timeout,
&acct_interim_interval, &vlan_id);
&acct_interim_interval, &vlan_id,
psk, &has_psk);
if (res == HOSTAPD_ACL_REJECT) {
printf("Station " MACSTR " not allowed to authenticate.\n",
MAC2STR(mgmt->sa));
@ -413,6 +417,16 @@ static void handle_auth(struct hostapd_data *hapd,
HOSTAPD_LEVEL_INFO, "VLAN ID %d", sta->vlan_id);
}
if (has_psk && hapd->conf->wpa_psk_radius != PSK_RADIUS_IGNORED) {
os_free(sta->psk);
sta->psk = os_malloc(PMK_LEN);
if (sta->psk)
os_memcpy(sta->psk, psk, PMK_LEN);
} else {
os_free(sta->psk);
sta->psk = NULL;
}
sta->flags &= ~WLAN_STA_PREAUTH;
ieee802_1x_notify_pre_auth(sta->eapol_sm, 0);

50
src/ap/ieee802_11_auth.c
View file

@ -21,6 +21,7 @@
#include "utils/common.h"
#include "utils/eloop.h"
#include "crypto/sha1.h"
#include "radius/radius.h"
#include "radius/radius_client.h"
#include "hostapd.h"
@ -40,6 +41,8 @@ struct hostapd_cached_radius_acl {
u32 session_timeout;
u32 acct_interim_interval;
int vlan_id;
int has_psk;
u8 psk[PMK_LEN];
};
@ -68,7 +71,8 @@ static void hostapd_acl_cache_free(struct hostapd_cached_radius_acl *acl_cache)
static int hostapd_acl_cache_get(struct hostapd_data *hapd, const u8 *addr,
u32 *session_timeout,
u32 *acct_interim_interval, int *vlan_id)
u32 *acct_interim_interval, int *vlan_id,
u8 *psk, int *has_psk)
{
struct hostapd_cached_radius_acl *entry;
struct os_time now;
@ -89,6 +93,10 @@ static int hostapd_acl_cache_get(struct hostapd_data *hapd, const u8 *addr,
entry->acct_interim_interval;
if (vlan_id)
*vlan_id = entry->vlan_id;
if (psk)
os_memcpy(psk, entry->psk, PMK_LEN);
if (has_psk)
*has_psk = entry->has_psk;
return entry->accepted;
}
@ -210,11 +218,14 @@ static int hostapd_radius_acl_query(struct hostapd_data *hapd, const u8 *addr,
* @session_timeout: Buffer for returning session timeout (from RADIUS)
* @acct_interim_interval: Buffer for returning account interval (from RADIUS)
* @vlan_id: Buffer for returning VLAN ID
* @psk: Buffer for returning WPA PSK
* @has_psk: Buffer for indicating whether psk was filled
* Returns: HOSTAPD_ACL_ACCEPT, HOSTAPD_ACL_REJECT, or HOSTAPD_ACL_PENDING
*/
int hostapd_allowed_address(struct hostapd_data *hapd, const u8 *addr,
const u8 *msg, size_t len, u32 *session_timeout,
u32 *acct_interim_interval, int *vlan_id)
u32 *acct_interim_interval, int *vlan_id,
u8 *psk, int *has_psk)
{
if (session_timeout)
*session_timeout = 0;
@ -222,6 +233,10 @@ int hostapd_allowed_address(struct hostapd_data *hapd, const u8 *addr,
*acct_interim_interval = 0;
if (vlan_id)
*vlan_id = 0;
if (has_psk)
*has_psk = 0;
if (psk)
os_memset(psk, 0, PMK_LEN);
if (hostapd_maclist_found(hapd->conf->accept_mac,
hapd->conf->num_accept_mac, addr, vlan_id))
@ -246,7 +261,7 @@ int hostapd_allowed_address(struct hostapd_data *hapd, const u8 *addr,
/* Check whether ACL cache has an entry for this station */
int res = hostapd_acl_cache_get(hapd, addr, session_timeout,
acct_interim_interval,
vlan_id);
vlan_id, psk, has_psk);
if (res == HOSTAPD_ACL_ACCEPT ||
res == HOSTAPD_ACL_ACCEPT_TIMEOUT)
return res;
@ -438,6 +453,9 @@ hostapd_acl_recv_radius(struct radius_msg *msg, struct radius_msg *req,
cache->timestamp = t.sec;
os_memcpy(cache->addr, query->addr, sizeof(cache->addr));
if (hdr->code == RADIUS_CODE_ACCESS_ACCEPT) {
int passphraselen;
char *passphrase;
if (radius_msg_get_attr_int32(msg, RADIUS_ATTR_SESSION_TIMEOUT,
&cache->session_timeout) == 0)
cache->accepted = HOSTAPD_ACL_ACCEPT_TIMEOUT;
@ -456,6 +474,32 @@ hostapd_acl_recv_radius(struct radius_msg *msg, struct radius_msg *req,
}
cache->vlan_id = radius_msg_get_vlanid(msg);
passphrase = radius_msg_get_tunnel_password(
msg, &passphraselen,
hapd->conf->radius->auth_server->shared_secret,
hapd->conf->radius->auth_server->shared_secret_len,
req);
cache->has_psk = passphrase != NULL;
if (passphrase != NULL) {
/* passphrase does not contain the NULL termination.
* Add it here as pbkdf2_sha1 requires it. */
char *strpassphrase = os_zalloc(passphraselen + 1);
if (strpassphrase) {
os_memcpy(strpassphrase, passphrase,
passphraselen);
pbkdf2_sha1(strpassphrase,
hapd->conf->ssid.ssid,
hapd->conf->ssid.ssid_len, 4096,
cache->psk, PMK_LEN);
os_free(strpassphrase);
}
os_free(passphrase);
}
if (hapd->conf->wpa_psk_radius == PSK_RADIUS_REQUIRED &&
cache->psk == NULL)
cache->accepted = HOSTAPD_ACL_REJECT;
} else
cache->accepted = HOSTAPD_ACL_REJECT;
cache->next = hapd->acl_cache;

3
src/ap/ieee802_11_auth.h
View file

@ -24,7 +24,8 @@ enum {
int hostapd_allowed_address(struct hostapd_data *hapd, const u8 *addr,
const u8 *msg, size_t len, u32 *session_timeout,
u32 *acct_interim_interval, int *vlan_id);
u32 *acct_interim_interval, int *vlan_id,
u8 *psk, int *has_psk);
int hostapd_acl_init(struct hostapd_data *hapd);
void hostapd_acl_deinit(struct hostapd_data *hapd);

1
src/ap/sta_info.c
View file

@ -228,6 +228,7 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
wpabuf_free(sta->p2p_ie);
os_free(sta->ht_capabilities);
os_free(sta->psk);
os_free(sta);
}

1
src/ap/sta_info.h
View file

@ -98,6 +98,7 @@ struct sta_info {
struct hostapd_ssid *ssid_probe; /* SSID selection based on ProbeReq */
int vlan_id;
u8 *psk; /* PSK from RADIUS authentication server */
struct ieee80211_ht_capabilities *ht_capabilities;

3
src/ap/wpa_auth_glue.c
View file

@ -186,6 +186,9 @@ static const u8 * hostapd_wpa_auth_get_psk(void *ctx, const u8 *addr,
const u8 *prev_psk)
{
struct hostapd_data *hapd = ctx;
struct sta_info *sta = ap_get_sta(hapd, addr);
if (sta && sta->psk)
return sta->psk;
return hostapd_get_psk(hapd->conf, addr, prev_psk);
}

116
src/radius/radius.c
View file

@ -218,6 +218,8 @@ static struct radius_attr_type radius_attrs[] =
{ RADIUS_ATTR_TUNNEL_TYPE, "Tunnel-Type", RADIUS_ATTR_HEXDUMP },
{ RADIUS_ATTR_TUNNEL_MEDIUM_TYPE, "Tunnel-Medium-Type",
RADIUS_ATTR_HEXDUMP },
{ RADIUS_ATTR_TUNNEL_PASSWORD, "Tunnel-Password",
RADIUS_ATTR_UNDIST },
{ RADIUS_ATTR_CONNECT_INFO, "Connect-Info", RADIUS_ATTR_TEXT },
{ RADIUS_ATTR_EAP_MESSAGE, "EAP-Message", RADIUS_ATTR_UNDIST },
{ RADIUS_ATTR_MESSAGE_AUTHENTICATOR, "Message-Authenticator",
@ -1275,6 +1277,120 @@ int radius_msg_get_vlanid(struct radius_msg *msg)
}
/**
* radius_msg_get_tunnel_password - Parse RADIUS attribute Tunnel-Password
* @msg: Received RADIUS message
* @keylen: Length of returned password
* @secret: RADIUS shared secret
* @secret_len: Length of secret
* @sent_msg: Sent RADIUS message
* Returns: pointer to password (free with os_free) or %NULL
*/
char * radius_msg_get_tunnel_password(struct radius_msg *msg, int *keylen,
const u8 *secret, size_t secret_len,
struct radius_msg *sent_msg)
{
u8 *buf = NULL;
size_t buflen;
const u8 *salt;
u8 *str;
const u8 *addr[3];
size_t len[3];
u8 hash[16];
u8 *pos;
size_t i;
struct radius_attr_hdr *attr;
const u8 *data;
size_t dlen;
const u8 *fdata = NULL; /* points to found item */
size_t fdlen = -1;
char *ret = NULL;
/* find attribute with lowest tag and check it */
for (i = 0; i < msg->attr_used; i++) {
attr = radius_get_attr_hdr(msg, i);
if (attr == NULL ||
attr->type != RADIUS_ATTR_TUNNEL_PASSWORD) {
continue;
}
if (attr->length <= 5)
continue;
data = (const u8 *) (attr + 1);
dlen = attr->length - sizeof(*attr);
if (dlen <= 3 || dlen % 16 != 3)
continue;
if (fdata != NULL && fdata[0] <= data[0])
continue;
fdata = data;
fdlen = dlen;
}
if (fdata == NULL)
goto out;
/* alloc writable memory for decryption */
buf = os_malloc(fdlen);
if (buf == NULL)
goto out;
os_memcpy(buf, fdata, fdlen);
buflen = fdlen;
/* init pointers */
salt = buf + 1;
str = buf + 3;
/* decrypt blocks */
pos = buf + buflen - 16; /* last block */
while (pos >= str + 16) { /* all but the first block */
addr[0] = secret;
len[0] = secret_len;
addr[1] = pos - 16;
len[1] = 16;
md5_vector(2, addr, len, hash);
for (i = 0; i < 16; i++)
pos[i] ^= hash[i];
pos -= 16;
}
/* decrypt first block */
if (str != pos)
goto out;
addr[0] = secret;
len[0] = secret_len;
addr[1] = sent_msg->hdr->authenticator;
len[1] = 16;
addr[2] = salt;
len[2] = 2;
md5_vector(3, addr, len, hash);
for (i = 0; i < 16; i++)
pos[i] ^= hash[i];
/* derive plaintext length from first subfield */
*keylen = (unsigned char) str[0];
if ((u8 *) (str + *keylen) >= (u8 *) (buf + buflen)) {
/* decryption error - invalid key length */
goto out;
}
if (*keylen == 0) {
/* empty password */
goto out;
}
/* copy passphrase into new buffer */
ret = os_malloc(*keylen);
if (ret)
os_memcpy(ret, str + 1, *keylen);
out:
/* return new buffer */
os_free(buf);
return ret;
}
void radius_free_class(struct radius_class_data *c)
{
size_t i;

4
src/radius/radius.h
View file

@ -82,6 +82,7 @@ enum { RADIUS_ATTR_USER_NAME = 1,
RADIUS_ATTR_NAS_PORT_TYPE = 61,
RADIUS_ATTR_TUNNEL_TYPE = 64,
RADIUS_ATTR_TUNNEL_MEDIUM_TYPE = 65,
RADIUS_ATTR_TUNNEL_PASSWORD = 69,
RADIUS_ATTR_CONNECT_INFO = 77,
RADIUS_ATTR_EAP_MESSAGE = 79,
RADIUS_ATTR_MESSAGE_AUTHENTICATOR = 80,
@ -231,6 +232,9 @@ radius_msg_add_attr_user_password(struct radius_msg *msg,
const u8 *secret, size_t secret_len);
int radius_msg_get_attr(struct radius_msg *msg, u8 type, u8 *buf, size_t len);
int radius_msg_get_vlanid(struct radius_msg *msg);
char * radius_msg_get_tunnel_password(struct radius_msg *msg, int *keylen,
const u8 *secret, size_t secret_len,
struct radius_msg *sent_msg);
static inline int radius_msg_add_attr_int32(struct radius_msg *msg, u8 type,
u32 value)