DPP2: Reconfig Authentication Request processing and Response generation

Extend Enrollee functionality to process Reconfig Authentication Request
message, derive the needed keys, and generate Reconfig Authentication
Response message.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
This commit is contained in:
Jouni Malinen 2020-05-09 16:30:09 +03:00 committed by Jouni Malinen
parent 3774b6bd03
commit 65e94351dc
6 changed files with 435 additions and 3 deletions

View File

@ -108,7 +108,7 @@ struct dpp_controller {
};
static void dpp_auth_fail(struct dpp_authentication *auth, const char *txt)
void dpp_auth_fail(struct dpp_authentication *auth, const char *txt)
{
wpa_msg(auth->msg_ctx, MSG_INFO, DPP_EVENT_FAIL "%s", txt);
}
@ -1002,6 +1002,7 @@ int dpp_prepare_channel_list(struct dpp_authentication *auth,
return -1;
auth->num_freq = 1;
auth->freq[0] = neg_freq;
auth->curr_freq = neg_freq;
return 0;
}
@ -3255,10 +3256,12 @@ void dpp_auth_deinit(struct dpp_authentication *auth)
dpp_configuration_free(auth->conf2_sta);
EVP_PKEY_free(auth->own_protocol_key);
EVP_PKEY_free(auth->peer_protocol_key);
EVP_PKEY_free(auth->reconfig_old_protocol_key);
wpabuf_free(auth->req_msg);
wpabuf_free(auth->resp_msg);
wpabuf_free(auth->conf_req);
wpabuf_free(auth->reconfig_req_msg);
wpabuf_free(auth->reconfig_resp_msg);
for (i = 0; i < auth->num_conf_obj; i++) {
struct dpp_config_obj *conf = &auth->conf_obj[i];
@ -4477,7 +4480,7 @@ static int dpp_parse_cred_legacy(struct dpp_config_obj *conf,
}
static EVP_PKEY * dpp_parse_jwk(struct json_token *jwk,
EVP_PKEY * dpp_parse_jwk(struct json_token *jwk,
const struct dpp_curve_params **key_curve)
{
struct json_token *token;

View File

@ -20,6 +20,7 @@
struct crypto_ecdh;
struct hostapd_ip_addr;
struct dpp_global;
struct json_token;
#ifdef CONFIG_TESTING_OPTIONS
#define DPP_VERSION (dpp_version_override)
@ -246,9 +247,11 @@ struct dpp_authentication {
u8 r_capab;
EVP_PKEY *own_protocol_key;
EVP_PKEY *peer_protocol_key;
EVP_PKEY *reconfig_old_protocol_key;
struct wpabuf *req_msg;
struct wpabuf *resp_msg;
struct wpabuf *reconfig_req_msg;
struct wpabuf *reconfig_resp_msg;
/* Intersection of possible frequencies for initiating DPP
* Authentication exchange */
unsigned int freq[DPP_BOOTSTRAP_MAX_FREQ];
@ -641,6 +644,13 @@ struct wpabuf * dpp_build_reconfig_announcement(const u8 *csign_key,
struct dpp_authentication *
dpp_reconfig_init(struct dpp_global *dpp, void *msg_ctx,
struct dpp_configurator *conf, unsigned int freq);
struct dpp_authentication *
dpp_reconfig_auth_req_rx(struct dpp_global *dpp, void *msg_ctx,
const char *own_connector,
const u8 *net_access_key, size_t net_access_key_len,
const u8 *csign_key, size_t csign_key_len,
unsigned int freq, const u8 *hdr,
const u8 *attr_start, size_t attr_len);
#endif /* CONFIG_DPP */
#endif /* DPP_H */

View File

@ -2236,6 +2236,114 @@ int dpp_pkex_derive_z(const u8 *mac_init, const u8 *mac_resp,
}
int dpp_reconfig_derive_ke_responder(struct dpp_authentication *auth,
const u8 *net_access_key,
size_t net_access_key_len,
struct json_token *peer_net_access_key)
{
BN_CTX *bnctx = NULL;
EVP_PKEY *own_key = NULL, *peer_key = NULL;
BIGNUM *sum = NULL, *q = NULL, *mx = NULL;
EC_POINT *m = NULL;
const EC_KEY *cR, *pR;
const EC_GROUP *group;
const BIGNUM *cR_bn, *pR_bn;
const EC_POINT *CI_point;
const EC_KEY *CI;
u8 Mx[DPP_MAX_SHARED_SECRET_LEN];
u8 prk[DPP_MAX_HASH_LEN];
const struct dpp_curve_params *curve;
int res = -1;
own_key = dpp_set_keypair(&auth->curve, net_access_key,
net_access_key_len);
if (!own_key) {
dpp_auth_fail(auth, "Failed to parse own netAccessKey");
goto fail;
}
peer_key = dpp_parse_jwk(peer_net_access_key, &curve);
if (!peer_key)
goto fail;
dpp_debug_print_key("DPP: Received netAccessKey", peer_key);
if (auth->curve != curve) {
wpa_printf(MSG_DEBUG,
"DPP: Mismatching netAccessKey curves (%s != %s)",
auth->curve->name, curve->name);
goto fail;
}
auth->own_protocol_key = dpp_gen_keypair(curve);
if (!auth->own_protocol_key)
goto fail;
/* M = { cR + pR } * CI */
cR = EVP_PKEY_get0_EC_KEY(own_key);
pR = EVP_PKEY_get0_EC_KEY(auth->own_protocol_key);
group = EC_KEY_get0_group(pR);
bnctx = BN_CTX_new();
sum = BN_new();
mx = BN_new();
q = BN_new();
m = EC_POINT_new(group);
if (!cR || !pR || !bnctx || !sum || !mx || !q || !m)
goto fail;
cR_bn = EC_KEY_get0_private_key(cR);
pR_bn = EC_KEY_get0_private_key(pR);
if (!cR_bn || !pR_bn)
goto fail;
CI = EVP_PKEY_get0_EC_KEY(peer_key);
CI_point = EC_KEY_get0_public_key(CI);
if (EC_GROUP_get_order(group, q, bnctx) != 1 ||
BN_mod_add(sum, cR_bn, pR_bn, q, bnctx) != 1 ||
EC_POINT_mul(group, m, NULL, CI_point, sum, bnctx) != 1 ||
EC_POINT_get_affine_coordinates_GFp(group, m, mx, NULL,
bnctx) != 1) {
wpa_printf(MSG_ERROR,
"OpenSSL: failed: %s",
ERR_error_string(ERR_get_error(), NULL));
goto fail;
}
if (dpp_bn2bin_pad(mx, Mx, curve->prime_len) < 0)
goto fail;
wpa_hexdump_key(MSG_DEBUG, "DPP: M.x", Mx, curve->prime_len);
/* ke = HKDF(I-nonce, "dpp reconfig key", M.x) */
/* HKDF-Extract(I-nonce, M.x) */
if (dpp_hmac(curve->hash_len, auth->i_nonce, curve->nonce_len,
Mx, curve->prime_len, prk) < 0)
goto fail;
wpa_hexdump_key(MSG_DEBUG, "DPP: PRK", prk, curve->hash_len);
/* HKDF-Expand(PRK, "dpp reconfig key", L) */
if (dpp_hkdf_expand(curve->hash_len, prk, curve->hash_len,
"dpp reconfig key", auth->ke, curve->hash_len) < 0)
goto fail;
wpa_hexdump_key(MSG_DEBUG,
"DPP: ke = HKDF(I-nonce, \"dpp reconfig key\", M.x)",
auth->ke, curve->hash_len);
res = 0;
EVP_PKEY_free(auth->reconfig_old_protocol_key);
auth->reconfig_old_protocol_key = own_key;
own_key = NULL;
fail:
forced_memzero(prk, sizeof(prk));
forced_memzero(Mx, sizeof(Mx));
EC_POINT_clear_free(m);
BN_free(q);
BN_clear_free(mx);
BN_clear_free(sum);
EVP_PKEY_free(own_key);
EVP_PKEY_free(peer_key);
BN_CTX_free(bnctx);
return res;
}
static char *
dpp_build_jws_prot_hdr(struct dpp_configurator *conf, size_t *signed1_len)
{

View File

@ -38,9 +38,12 @@ int dpp_connector_match_groups(struct json_token *own_root,
struct json_token *peer_root, bool reconfig);
int dpp_build_jwk(struct wpabuf *buf, const char *name, EVP_PKEY *key,
const char *kid, const struct dpp_curve_params *curve);
EVP_PKEY * dpp_parse_jwk(struct json_token *jwk,
const struct dpp_curve_params **key_curve);
int dpp_prepare_channel_list(struct dpp_authentication *auth,
unsigned int neg_freq,
struct hostapd_hw_modes *own_modes, u16 num_modes);
void dpp_auth_fail(struct dpp_authentication *auth, const char *txt);
/* dpp_crypto.c */
@ -116,6 +119,10 @@ int dpp_pkex_derive_z(const u8 *mac_init, const u8 *mac_resp,
const char *code,
const u8 *Kx, size_t Kx_len,
u8 *z, unsigned int hash_len);
int dpp_reconfig_derive_ke_responder(struct dpp_authentication *auth,
const u8 *net_access_key,
size_t net_access_key_len,
struct json_token *peer_net_access_key);
char * dpp_sign_connector(struct dpp_configurator *conf,
const struct wpabuf *dppcon);
int dpp_test_gen_invalid_key(struct wpabuf *msg,

View File

@ -7,11 +7,15 @@
*/
#include "utils/includes.h"
#include <openssl/opensslv.h>
#include <openssl/err.h>
#include "utils/common.h"
#include "utils/json.h"
#include "crypto/crypto.h"
#include "crypto/random.h"
#include "crypto/aes.h"
#include "crypto/aes_siv.h"
#include "dpp.h"
#include "dpp_i.h"
@ -207,4 +211,254 @@ fail:
goto out;
}
static int dpp_reconfig_build_resp(struct dpp_authentication *auth,
const char *own_connector,
struct wpabuf *conn_status)
{
struct wpabuf *msg = NULL, *clear, *pr = NULL;
u8 *attr_start, *attr_end;
size_t clear_len, attr_len, len[2];
const u8 *addr[2];
u8 *wrapped;
int res = -1;
/* Build DPP Reconfig Authentication Response frame attributes */
clear_len = 2 * (4 + auth->curve->nonce_len) +
4 + wpabuf_len(conn_status);
clear = wpabuf_alloc(clear_len);
if (!clear)
goto fail;
/* I-nonce (wrapped) */
wpabuf_put_le16(clear, DPP_ATTR_I_NONCE);
wpabuf_put_le16(clear, auth->curve->nonce_len);
wpabuf_put_data(clear, auth->i_nonce, auth->curve->nonce_len);
/* R-nonce (wrapped) */
wpabuf_put_le16(clear, DPP_ATTR_R_NONCE);
wpabuf_put_le16(clear, auth->curve->nonce_len);
wpabuf_put_data(clear, auth->r_nonce, auth->curve->nonce_len);
/* Connection Status (wrapped) */
wpabuf_put_le16(clear, DPP_ATTR_CONN_STATUS);
wpabuf_put_le16(clear, wpabuf_len(conn_status));
wpabuf_put_buf(clear, conn_status);
pr = dpp_get_pubkey_point(auth->own_protocol_key, 0);
if (!pr)
goto fail;
attr_len = 4 + 1 + 4 + 1 +
4 + os_strlen(own_connector) +
4 + wpabuf_len(pr) +
4 + wpabuf_len(clear) + AES_BLOCK_SIZE;
msg = dpp_alloc_msg(DPP_PA_RECONFIG_AUTH_RESP, attr_len);
if (!msg)
goto fail;
attr_start = wpabuf_put(msg, 0);
/* Transaction ID */
wpabuf_put_le16(msg, DPP_ATTR_TRANSACTION_ID);
wpabuf_put_le16(msg, 1);
wpabuf_put_u8(msg, auth->transaction_id);
/* Protocol Version */
wpabuf_put_le16(msg, DPP_ATTR_PROTOCOL_VERSION);
wpabuf_put_le16(msg, 1);
wpabuf_put_u8(msg, DPP_VERSION);
/* R-Connector */
wpabuf_put_le16(msg, DPP_ATTR_CONNECTOR);
wpabuf_put_le16(msg, os_strlen(own_connector));
wpabuf_put_str(msg, own_connector);
/* Responder Protocol Key (Pr) */
wpabuf_put_le16(msg, DPP_ATTR_R_PROTOCOL_KEY);
wpabuf_put_le16(msg, wpabuf_len(pr));
wpabuf_put_buf(msg, pr);
attr_end = wpabuf_put(msg, 0);
/* OUI, OUI type, Crypto Suite, DPP frame type */
addr[0] = wpabuf_head_u8(msg) + 2;
len[0] = 3 + 1 + 1 + 1;
wpa_hexdump(MSG_DEBUG, "DDP: AES-SIV AD[0]", addr[0], len[0]);
/* Attributes before Wrapped Data */
addr[1] = attr_start;
len[1] = attr_end - attr_start;
wpa_hexdump(MSG_DEBUG, "DDP: AES-SIV AD[1]", addr[1], len[1]);
/* Wrapped Data: {I-nonce, R-nonce, Connection Status}ke */
wpabuf_put_le16(msg, DPP_ATTR_WRAPPED_DATA);
wpabuf_put_le16(msg, wpabuf_len(clear) + AES_BLOCK_SIZE);
wrapped = wpabuf_put(msg, wpabuf_len(clear) + AES_BLOCK_SIZE);
wpa_hexdump_buf(MSG_DEBUG, "DPP: AES-SIV cleartext", clear);
if (aes_siv_encrypt(auth->ke, auth->curve->hash_len,
wpabuf_head(clear), wpabuf_len(clear),
2, addr, len, wrapped) < 0)
goto fail;
wpa_hexdump_buf(MSG_DEBUG,
"DPP: Reconfig Authentication Response frame attributes",
msg);
wpabuf_free(auth->reconfig_resp_msg);
auth->reconfig_resp_msg = msg;
res = 0;
out:
wpabuf_free(clear);
wpabuf_free(pr);
return res;
fail:
wpabuf_free(msg);
goto out;
}
struct dpp_authentication *
dpp_reconfig_auth_req_rx(struct dpp_global *dpp, void *msg_ctx,
const char *own_connector,
const u8 *net_access_key, size_t net_access_key_len,
const u8 *csign_key, size_t csign_key_len,
unsigned int freq, const u8 *hdr,
const u8 *attr_start, size_t attr_len)
{
struct dpp_authentication *auth = NULL;
const u8 *trans_id, *version, *i_connector, *i_nonce;
u16 trans_id_len, version_len, i_connector_len, i_nonce_len;
struct dpp_signed_connector_info info;
enum dpp_status_error res;
struct json_token *root = NULL, *own_root = NULL, *token;
unsigned char *own_conn = NULL;
struct wpabuf *conn_status = NULL;
os_memset(&info, 0, sizeof(info));
trans_id = dpp_get_attr(attr_start, attr_len, DPP_ATTR_TRANSACTION_ID,
&trans_id_len);
if (!trans_id || trans_id_len != 1) {
wpa_printf(MSG_DEBUG,
"DPP: Peer did not include Transaction ID");
goto fail;
}
version = dpp_get_attr(attr_start, attr_len, DPP_ATTR_PROTOCOL_VERSION,
&version_len);
if (!version || version_len < 1 || version[0] < 2) {
wpa_printf(MSG_DEBUG,
"DPP: Missing or invalid Protocol Version attribute");
goto fail;
}
i_connector = dpp_get_attr(attr_start, attr_len, DPP_ATTR_CONNECTOR,
&i_connector_len);
if (!i_connector) {
wpa_printf(MSG_DEBUG, "DPP: Missing I-Connector attribute");
goto fail;
}
wpa_hexdump_ascii(MSG_DEBUG, "DPP: I-Connector",
i_connector, i_connector_len);
i_nonce = dpp_get_attr(attr_start, attr_len, DPP_ATTR_I_NONCE,
&i_nonce_len);
if (!i_nonce || i_nonce_len > DPP_MAX_NONCE_LEN) {
wpa_printf(MSG_DEBUG,
"DPP: Missing or invalid I-Nonce attribute");
goto fail;
}
wpa_hexdump(MSG_DEBUG, "DPP: I-Nonce", i_nonce, i_nonce_len);
res = dpp_check_signed_connector(&info, csign_key, csign_key_len,
i_connector, i_connector_len);
if (res != DPP_STATUS_OK) {
wpa_printf(MSG_DEBUG, "DPP: Invalid I-Connector");
goto fail;
}
root = json_parse((const char *) info.payload, info.payload_len);
own_root = dpp_parse_own_connector(own_connector);
if (!root || !own_root ||
!dpp_connector_match_groups(own_root, root, true)) {
wpa_printf(MSG_DEBUG,
"DPP: I-Connector does not include compatible group netrole with own connector");
goto fail;
}
token = json_get_member(root, "expiry");
if (token && token->type == JSON_STRING &&
dpp_key_expired(token->string, NULL)) {
wpa_printf(MSG_DEBUG,
"DPP: I-Connector (netAccessKey) has expired");
goto fail;
}
token = json_get_member(root, "netAccessKey");
if (!token || token->type != JSON_OBJECT) {
wpa_printf(MSG_DEBUG, "DPP: No netAccessKey object found");
goto fail;
}
auth = dpp_alloc_auth(dpp, msg_ctx);
if (!auth)
return NULL;
auth->reconfig = 1;
auth->allowed_roles = DPP_CAPAB_ENROLLEE;
if (dpp_prepare_channel_list(auth, freq, NULL, 0) < 0)
goto fail;
auth->transaction_id = trans_id[0];
auth->peer_version = version[0];
wpa_printf(MSG_DEBUG, "DPP: Peer protocol version %u",
auth->peer_version);
os_memcpy(auth->i_nonce, i_nonce, i_nonce_len);
if (dpp_reconfig_derive_ke_responder(auth, net_access_key,
net_access_key_len, token) < 0)
goto fail;
if (i_nonce_len != auth->curve->nonce_len) {
wpa_printf(MSG_DEBUG,
"DPP: Unexpected I-nonce length %u (curve nonce len %zu)",
i_nonce_len, auth->curve->nonce_len);
goto fail;
}
if (random_get_bytes(auth->r_nonce, auth->curve->nonce_len)) {
wpa_printf(MSG_ERROR, "DPP: Failed to generate R-nonce");
goto fail;
}
wpa_hexdump_key(MSG_DEBUG, "DPP: R-nonce",
auth->r_nonce, auth->curve->nonce_len);
/* Build Connection Status object */
/* TODO: Get appropriate result value */
/* TODO: ssid64 and channelList */
conn_status = dpp_build_conn_status(DPP_STATUS_NO_AP, NULL, 0, NULL);
if (!conn_status)
goto fail;
if (dpp_reconfig_build_resp(auth, own_connector, conn_status) < 0)
goto fail;
out:
os_free(info.payload);
os_free(own_conn);
json_free(root);
json_free(own_root);
wpabuf_free(conn_status);
return auth;
fail:
dpp_auth_deinit(auth);
auth = NULL;
goto out;
}
#endif /* CONFIG_DPP2 */

View File

@ -1915,6 +1915,53 @@ wpas_dpp_rx_reconfig_announcement(struct wpa_supplicant *wpa_s, const u8 *src,
}
}
static void
wpas_dpp_rx_reconfig_auth_req(struct wpa_supplicant *wpa_s, const u8 *src,
const u8 *hdr, const u8 *buf, size_t len,
unsigned int freq)
{
struct wpa_ssid *ssid;
struct dpp_authentication *auth;
wpa_printf(MSG_DEBUG, "DPP: Reconfig Authentication Request from "
MACSTR, MAC2STR(src));
if (!wpa_s->dpp || wpa_s->dpp_auth ||
!wpa_s->dpp_reconfig_announcement || !wpa_s->dpp_reconfig_ssid)
return;
for (ssid = wpa_s->conf->ssid; ssid; ssid = ssid->next) {
if (ssid == wpa_s->dpp_reconfig_ssid &&
ssid->id == wpa_s->dpp_reconfig_ssid_id)
break;
}
if (!ssid || !ssid->dpp_connector || !ssid->dpp_netaccesskey ||
!ssid->dpp_csign)
return;
auth = dpp_reconfig_auth_req_rx(wpa_s->dpp, wpa_s, ssid->dpp_connector,
ssid->dpp_netaccesskey,
ssid->dpp_netaccesskey_len,
ssid->dpp_csign, ssid->dpp_csign_len,
freq, hdr, buf, len);
if (!auth)
return;
os_memcpy(auth->peer_mac_addr, src, ETH_ALEN);
wpa_s->dpp_auth = auth;
wpas_dpp_chirp_stop(wpa_s);
wpa_msg(wpa_s, MSG_INFO, DPP_EVENT_TX "dst=" MACSTR " freq=%u type=%d",
MAC2STR(src), freq, DPP_PA_RECONFIG_AUTH_RESP);
if (offchannel_send_action(wpa_s, freq, src, wpa_s->own_addr, broadcast,
wpabuf_head(auth->reconfig_resp_msg),
wpabuf_len(auth->reconfig_resp_msg),
500, wpas_dpp_tx_status, 0) < 0) {
dpp_auth_deinit(wpa_s->dpp_auth);
wpa_s->dpp_auth = NULL;
}
}
#endif /* CONFIG_DPP2 */
@ -2480,6 +2527,9 @@ void wpas_dpp_rx_action(struct wpa_supplicant *wpa_s, const u8 *src,
wpas_dpp_rx_reconfig_announcement(wpa_s, src, hdr, buf, len,
freq);
break;
case DPP_PA_RECONFIG_AUTH_REQ:
wpas_dpp_rx_reconfig_auth_req(wpa_s, src, hdr, buf, len, freq);
break;
#endif /* CONFIG_DPP2 */
default:
wpa_printf(MSG_DEBUG,