wpa_auth: Make struct wpa_auth_callbacks const

Instead of copying the struct wpa_auth_callbacks, just keep a pointer to
it, keep the context pointer separate, and let the user just provide a
static const structure. This reduces the attack surface of heap
overwrites, since the function pointers move elsewhere.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

src/ap/wpa_auth.c

@@ -75,8 +75,8 @@ static const int dot11RSNAConfigSATimeout = 60;
 static inline int wpa_auth_mic_failure_report(
 	struct wpa_authenticator *wpa_auth, const u8 *addr)
 {
-	if (wpa_auth->cb.mic_failure_report)
-		return wpa_auth->cb.mic_failure_report(wpa_auth->cb.ctx, addr);
+	if (wpa_auth->cb->mic_failure_report)
+		return wpa_auth->cb->mic_failure_report(wpa_auth->cb_ctx, addr);
 	return 0;
 }
 
@@ -84,8 +84,8 @@ static inline int wpa_auth_mic_failure_report(
 static inline void wpa_auth_psk_failure_report(
 	struct wpa_authenticator *wpa_auth, const u8 *addr)
 {
-	if (wpa_auth->cb.psk_failure_report)
-		wpa_auth->cb.psk_failure_report(wpa_auth->cb.ctx, addr);
+	if (wpa_auth->cb->psk_failure_report)
+		wpa_auth->cb->psk_failure_report(wpa_auth->cb_ctx, addr);
 }
 
 
@@ -93,17 +93,17 @@ static inline void wpa_auth_set_eapol(struct wpa_authenticator *wpa_auth,
 				      const u8 *addr, wpa_eapol_variable var,
 				      int value)
 {
-	if (wpa_auth->cb.set_eapol)
-		wpa_auth->cb.set_eapol(wpa_auth->cb.ctx, addr, var, value);
+	if (wpa_auth->cb->set_eapol)
+		wpa_auth->cb->set_eapol(wpa_auth->cb_ctx, addr, var, value);
 }
 
 
 static inline int wpa_auth_get_eapol(struct wpa_authenticator *wpa_auth,
 				     const u8 *addr, wpa_eapol_variable var)
 {
-	if (wpa_auth->cb.get_eapol == NULL)
+	if (wpa_auth->cb->get_eapol == NULL)
 		return -1;
-	return wpa_auth->cb.get_eapol(wpa_auth->cb.ctx, addr, var);
+	return wpa_auth->cb->get_eapol(wpa_auth->cb_ctx, addr, var);
 }
 
 
@@ -112,19 +112,19 @@ static inline const u8 * wpa_auth_get_psk(struct wpa_authenticator *wpa_auth,
 					  const u8 *p2p_dev_addr,
 					  const u8 *prev_psk)
 {
-	if (wpa_auth->cb.get_psk == NULL)
+	if (wpa_auth->cb->get_psk == NULL)
 		return NULL;
-	return wpa_auth->cb.get_psk(wpa_auth->cb.ctx, addr, p2p_dev_addr,
-				    prev_psk);
+	return wpa_auth->cb->get_psk(wpa_auth->cb_ctx, addr, p2p_dev_addr,
+				     prev_psk);
 }
 
 
 static inline int wpa_auth_get_msk(struct wpa_authenticator *wpa_auth,
 				   const u8 *addr, u8 *msk, size_t *len)
 {
-	if (wpa_auth->cb.get_msk == NULL)
+	if (wpa_auth->cb->get_msk == NULL)
 		return -1;
-	return wpa_auth->cb.get_msk(wpa_auth->cb.ctx, addr, msk, len);
+	return wpa_auth->cb->get_msk(wpa_auth->cb_ctx, addr, msk, len);
 }
 
 
@@ -133,19 +133,19 @@ static inline int wpa_auth_set_key(struct wpa_authenticator *wpa_auth,
 				   enum wpa_alg alg, const u8 *addr, int idx,
 				   u8 *key, size_t key_len)
 {
-	if (wpa_auth->cb.set_key == NULL)
+	if (wpa_auth->cb->set_key == NULL)
 		return -1;
-	return wpa_auth->cb.set_key(wpa_auth->cb.ctx, vlan_id, alg, addr, idx,
-				    key, key_len);
+	return wpa_auth->cb->set_key(wpa_auth->cb_ctx, vlan_id, alg, addr, idx,
+				     key, key_len);
 }
 
 
 static inline int wpa_auth_get_seqnum(struct wpa_authenticator *wpa_auth,
 				      const u8 *addr, int idx, u8 *seq)
 {
-	if (wpa_auth->cb.get_seqnum == NULL)
+	if (wpa_auth->cb->get_seqnum == NULL)
 		return -1;
-	return wpa_auth->cb.get_seqnum(wpa_auth->cb.ctx, addr, idx, seq);
+	return wpa_auth->cb->get_seqnum(wpa_auth->cb_ctx, addr, idx, seq);
 }
 
 
@@ -153,10 +153,10 @@ static inline int
 wpa_auth_send_eapol(struct wpa_authenticator *wpa_auth, const u8 *addr,
 		    const u8 *data, size_t data_len, int encrypt)
 {
-	if (wpa_auth->cb.send_eapol == NULL)
+	if (wpa_auth->cb->send_eapol == NULL)
 		return -1;
-	return wpa_auth->cb.send_eapol(wpa_auth->cb.ctx, addr, data, data_len,
-				       encrypt);
+	return wpa_auth->cb->send_eapol(wpa_auth->cb_ctx, addr, data, data_len,
+					encrypt);
 }
 
 
@@ -164,9 +164,9 @@ wpa_auth_send_eapol(struct wpa_authenticator *wpa_auth, const u8 *addr,
 static inline int wpa_auth_start_ampe(struct wpa_authenticator *wpa_auth,
 				      const u8 *addr)
 {
-	if (wpa_auth->cb.start_ampe == NULL)
+	if (wpa_auth->cb->start_ampe == NULL)
 		return -1;
-	return wpa_auth->cb.start_ampe(wpa_auth->cb.ctx, addr);
+	return wpa_auth->cb->start_ampe(wpa_auth->cb_ctx, addr);
 }
 #endif /* CONFIG_MESH */
 
@@ -175,9 +175,9 @@ int wpa_auth_for_each_sta(struct wpa_authenticator *wpa_auth,
 			  int (*cb)(struct wpa_state_machine *sm, void *ctx),
 			  void *cb_ctx)
 {
-	if (wpa_auth->cb.for_each_sta == NULL)
+	if (wpa_auth->cb->for_each_sta == NULL)
 		return 0;
-	return wpa_auth->cb.for_each_sta(wpa_auth->cb.ctx, cb, cb_ctx);
+	return wpa_auth->cb->for_each_sta(wpa_auth->cb_ctx, cb, cb_ctx);
 }
 
 
@@ -185,18 +185,18 @@ int wpa_auth_for_each_auth(struct wpa_authenticator *wpa_auth,
 			   int (*cb)(struct wpa_authenticator *a, void *ctx),
 			   void *cb_ctx)
 {
-	if (wpa_auth->cb.for_each_auth == NULL)
+	if (wpa_auth->cb->for_each_auth == NULL)
 		return 0;
-	return wpa_auth->cb.for_each_auth(wpa_auth->cb.ctx, cb, cb_ctx);
+	return wpa_auth->cb->for_each_auth(wpa_auth->cb_ctx, cb, cb_ctx);
 }
 
 
 void wpa_auth_logger(struct wpa_authenticator *wpa_auth, const u8 *addr,
 		     logger_level level, const char *txt)
 {
-	if (wpa_auth->cb.logger == NULL)
+	if (wpa_auth->cb->logger == NULL)
 		return;
-	wpa_auth->cb.logger(wpa_auth->cb.ctx, addr, level, txt);
+	wpa_auth->cb->logger(wpa_auth->cb_ctx, addr, level, txt);
 }
 
 
@@ -207,7 +207,7 @@ void wpa_auth_vlogger(struct wpa_authenticator *wpa_auth, const u8 *addr,
 	int maxlen;
 	va_list ap;
 
-	if (wpa_auth->cb.logger == NULL)
+	if (wpa_auth->cb->logger == NULL)
 		return;
 
 	maxlen = os_strlen(fmt) + 100;
@@ -228,11 +228,11 @@ void wpa_auth_vlogger(struct wpa_authenticator *wpa_auth, const u8 *addr,
 static void wpa_sta_disconnect(struct wpa_authenticator *wpa_auth,
 			       const u8 *addr)
 {
-	if (wpa_auth->cb.disconnect == NULL)
+	if (wpa_auth->cb->disconnect == NULL)
 		return;
 	wpa_printf(MSG_DEBUG, "wpa_sta_disconnect STA " MACSTR, MAC2STR(addr));
-	wpa_auth->cb.disconnect(wpa_auth->cb.ctx, addr,
-				WLAN_REASON_PREV_AUTH_NOT_VALID);
+	wpa_auth->cb->disconnect(wpa_auth->cb_ctx, addr,
+				 WLAN_REASON_PREV_AUTH_NOT_VALID);
 }
 
 
@@ -416,7 +416,8 @@ static struct wpa_group * wpa_group_init(struct wpa_authenticator *wpa_auth,
  */
 struct wpa_authenticator * wpa_init(const u8 *addr,
 				    struct wpa_auth_config *conf,
-				    struct wpa_auth_callbacks *cb)
+				    const struct wpa_auth_callbacks *cb,
+				    void *cb_ctx)
 {
 	struct wpa_authenticator *wpa_auth;
 
@@ -425,7 +426,8 @@ struct wpa_authenticator * wpa_init(const u8 *addr,
 		return NULL;
 	os_memcpy(wpa_auth->addr, addr, ETH_ALEN);
 	os_memcpy(&wpa_auth->conf, conf, sizeof(*conf));
-	os_memcpy(&wpa_auth->cb, cb, sizeof(*cb));
+	wpa_auth->cb = cb;
+	wpa_auth->cb_ctx = cb_ctx;
 
 	if (wpa_auth_gen_wpa_ie(wpa_auth)) {
 		wpa_printf(MSG_ERROR, "Could not generate WPA IE.");
@@ -1949,7 +1951,7 @@ SM_STATE(WPA_PTK, INITPMK)
 #endif /* CONFIG_IEEE80211R_AP */
 	} else {
 		wpa_printf(MSG_DEBUG, "WPA: Could not get PMK, get_msk: %p",
-			   sm->wpa_auth->cb.get_msk);
+			   sm->wpa_auth->cb->get_msk);
 		sm->Disconnect = TRUE;
 		return;
 	}

src/ap/wpa_auth.h

@@ -198,7 +198,6 @@ typedef enum {
 } wpa_eapol_variable;
 
 struct wpa_auth_callbacks {
-	void *ctx;
 	void (*logger)(void *ctx, const u8 *addr, logger_level level,
 		       const char *txt);
 	void (*disconnect)(void *ctx, const u8 *addr, u16 reason);
@@ -235,7 +234,8 @@ struct wpa_auth_callbacks {
 
 struct wpa_authenticator * wpa_init(const u8 *addr,
 				    struct wpa_auth_config *conf,
-				    struct wpa_auth_callbacks *cb);
+				    const struct wpa_auth_callbacks *cb,
+				    void *cb_ctx);
 int wpa_init_keys(struct wpa_authenticator *wpa_auth);
 void wpa_deinit(struct wpa_authenticator *wpa_auth);
 int wpa_reconfig(struct wpa_authenticator *wpa_auth,

src/ap/wpa_auth_ft.c

@@ -33,21 +33,21 @@ static int wpa_ft_send_rrb_auth_resp(struct wpa_state_machine *sm,
 static int wpa_ft_rrb_send(struct wpa_authenticator *wpa_auth, const u8 *dst,
 			   const u8 *data, size_t data_len)
 {
-	if (wpa_auth->cb.send_ether == NULL)
+	if (wpa_auth->cb->send_ether == NULL)
 		return -1;
 	wpa_printf(MSG_DEBUG, "FT: RRB send to " MACSTR, MAC2STR(dst));
-	return wpa_auth->cb.send_ether(wpa_auth->cb.ctx, dst, ETH_P_RRB,
-				       data, data_len);
+	return wpa_auth->cb->send_ether(wpa_auth->cb_ctx, dst, ETH_P_RRB,
+					data, data_len);
 }
 
 
 static int wpa_ft_action_send(struct wpa_authenticator *wpa_auth,
 			      const u8 *dst, const u8 *data, size_t data_len)
 {
-	if (wpa_auth->cb.send_ft_action == NULL)
+	if (wpa_auth->cb->send_ft_action == NULL)
 		return -1;
-	return wpa_auth->cb.send_ft_action(wpa_auth->cb.ctx, dst,
-					   data, data_len);
+	return wpa_auth->cb->send_ft_action(wpa_auth->cb_ctx, dst,
+					    data, data_len);
 }
 
 
@@ -55,19 +55,19 @@ static const u8 * wpa_ft_get_psk(struct wpa_authenticator *wpa_auth,
 				 const u8 *addr, const u8 *p2p_dev_addr,
 				 const u8 *prev_psk)
 {
-	if (wpa_auth->cb.get_psk == NULL)
+	if (wpa_auth->cb->get_psk == NULL)
 		return NULL;
-	return wpa_auth->cb.get_psk(wpa_auth->cb.ctx, addr, p2p_dev_addr,
-				    prev_psk);
+	return wpa_auth->cb->get_psk(wpa_auth->cb_ctx, addr, p2p_dev_addr,
+				     prev_psk);
 }
 
 
 static struct wpa_state_machine *
 wpa_ft_add_sta(struct wpa_authenticator *wpa_auth, const u8 *sta_addr)
 {
-	if (wpa_auth->cb.add_sta == NULL)
+	if (wpa_auth->cb->add_sta == NULL)
 		return NULL;
-	return wpa_auth->cb.add_sta(wpa_auth->cb.ctx, sta_addr);
+	return wpa_auth->cb->add_sta(wpa_auth->cb_ctx, sta_addr);
 }
 
 
@@ -75,12 +75,12 @@ static int wpa_ft_add_tspec(struct wpa_authenticator *wpa_auth,
 			    const u8 *sta_addr,
 			    u8 *tspec_ie, size_t tspec_ielen)
 {
-	if (wpa_auth->cb.add_tspec == NULL) {
+	if (wpa_auth->cb->add_tspec == NULL) {
 		wpa_printf(MSG_DEBUG, "FT: add_tspec is not initialized");
 		return -1;
 	}
-	return wpa_auth->cb.add_tspec(wpa_auth->cb.ctx, sta_addr, tspec_ie,
-				      tspec_ielen);
+	return wpa_auth->cb->add_tspec(wpa_auth->cb_ctx, sta_addr, tspec_ie,
+				       tspec_ielen);
 }
 
 
@@ -418,9 +418,9 @@ int wpa_auth_derive_ptk_ft(struct wpa_state_machine *sm, const u8 *pmk,
 static inline int wpa_auth_get_seqnum(struct wpa_authenticator *wpa_auth,
 				      const u8 *addr, int idx, u8 *seq)
 {
-	if (wpa_auth->cb.get_seqnum == NULL)
+	if (wpa_auth->cb->get_seqnum == NULL)
 		return -1;
-	return wpa_auth->cb.get_seqnum(wpa_auth->cb.ctx, addr, idx, seq);
+	return wpa_auth->cb->get_seqnum(wpa_auth->cb_ctx, addr, idx, seq);
 }
 
 
@@ -773,10 +773,10 @@ static inline int wpa_auth_set_key(struct wpa_authenticator *wpa_auth,
 				   enum wpa_alg alg, const u8 *addr, int idx,
 				   u8 *key, size_t key_len)
 {
-	if (wpa_auth->cb.set_key == NULL)
+	if (wpa_auth->cb->set_key == NULL)
 		return -1;
-	return wpa_auth->cb.set_key(wpa_auth->cb.ctx, vlan_id, alg, addr, idx,
-				    key, key_len);
+	return wpa_auth->cb->set_key(wpa_auth->cb_ctx, vlan_id, alg, addr, idx,
+				     key, key_len);
 }
 
 

src/ap/wpa_auth_glue.c

@@ -595,7 +595,27 @@ static int hostapd_wpa_auth_add_tspec(void *ctx, const u8 *sta_addr,
 int hostapd_setup_wpa(struct hostapd_data *hapd)
 {
 	struct wpa_auth_config _conf;
-	struct wpa_auth_callbacks cb;
+	static const struct wpa_auth_callbacks cb = {
+		.logger = hostapd_wpa_auth_logger,
+		.disconnect = hostapd_wpa_auth_disconnect,
+		.mic_failure_report = hostapd_wpa_auth_mic_failure_report,
+		.psk_failure_report = hostapd_wpa_auth_psk_failure_report,
+		.set_eapol = hostapd_wpa_auth_set_eapol,
+		.get_eapol = hostapd_wpa_auth_get_eapol,
+		.get_psk = hostapd_wpa_auth_get_psk,
+		.get_msk = hostapd_wpa_auth_get_msk,
+		.set_key = hostapd_wpa_auth_set_key,
+		.get_seqnum = hostapd_wpa_auth_get_seqnum,
+		.send_eapol = hostapd_wpa_auth_send_eapol,
+		.for_each_sta = hostapd_wpa_auth_for_each_sta,
+		.for_each_auth = hostapd_wpa_auth_for_each_auth,
+		.send_ether = hostapd_wpa_auth_send_ether,
+#ifdef CONFIG_IEEE80211R_AP
+		.send_ft_action = hostapd_wpa_auth_send_ft_action,
+		.add_sta = hostapd_wpa_auth_add_sta,
+		.add_tspec = hostapd_wpa_auth_add_tspec,
+#endif /* CONFIG_IEEE80211R_AP */
+	};
 	const u8 *wpa_ie;
 	size_t wpa_ie_len;
 
@@ -604,28 +624,7 @@ int hostapd_setup_wpa(struct hostapd_data *hapd)
 		_conf.tx_status = 1;
 	if (hapd->iface->drv_flags & WPA_DRIVER_FLAGS_AP_MLME)
 		_conf.ap_mlme = 1;
-	os_memset(&cb, 0, sizeof(cb));
-	cb.ctx = hapd;
-	cb.logger = hostapd_wpa_auth_logger;
-	cb.disconnect = hostapd_wpa_auth_disconnect;
-	cb.mic_failure_report = hostapd_wpa_auth_mic_failure_report;
-	cb.psk_failure_report = hostapd_wpa_auth_psk_failure_report;
-	cb.set_eapol = hostapd_wpa_auth_set_eapol;
-	cb.get_eapol = hostapd_wpa_auth_get_eapol;
-	cb.get_psk = hostapd_wpa_auth_get_psk;
-	cb.get_msk = hostapd_wpa_auth_get_msk;
-	cb.set_key = hostapd_wpa_auth_set_key;
-	cb.get_seqnum = hostapd_wpa_auth_get_seqnum;
-	cb.send_eapol = hostapd_wpa_auth_send_eapol;
-	cb.for_each_sta = hostapd_wpa_auth_for_each_sta;
-	cb.for_each_auth = hostapd_wpa_auth_for_each_auth;
-	cb.send_ether = hostapd_wpa_auth_send_ether;
-#ifdef CONFIG_IEEE80211R_AP
-	cb.send_ft_action = hostapd_wpa_auth_send_ft_action;
-	cb.add_sta = hostapd_wpa_auth_add_sta;
-	cb.add_tspec = hostapd_wpa_auth_add_tspec;
-#endif /* CONFIG_IEEE80211R_AP */
-	hapd->wpa_auth = wpa_init(hapd->own_addr, &_conf, &cb);
+	hapd->wpa_auth = wpa_init(hapd->own_addr, &_conf, &cb, hapd);
 	if (hapd->wpa_auth == NULL) {
 		wpa_printf(MSG_ERROR, "WPA initialization failed.");
 		return -1;

src/ap/wpa_auth_i.h

@@ -203,7 +203,8 @@ struct wpa_authenticator {
 	struct wpa_stsl_negotiation *stsl_negotiations;
 
 	struct wpa_auth_config conf;
-	struct wpa_auth_callbacks cb;
+	const struct wpa_auth_callbacks *cb;
+	void *cb_ctx;
 
 	u8 *wpa_ie;
 	size_t wpa_ie_len;

wpa_supplicant/ibss_rsn.c

@@ -408,7 +408,15 @@ static int ibss_rsn_auth_init_group(struct ibss_rsn *ibss_rsn,
 				    const u8 *own_addr, struct wpa_ssid *ssid)
 {
 	struct wpa_auth_config conf;
-	struct wpa_auth_callbacks cb;
+	static const struct wpa_auth_callbacks cb = {
+		.logger = auth_logger,
+		.set_eapol = auth_set_eapol,
+		.send_eapol = auth_send_eapol,
+		.get_psk = auth_get_psk,
+		.set_key = auth_set_key,
+		.for_each_sta = auth_for_each_sta,
+		.disconnect = ibss_rsn_disconnect,
+	};
 
 	wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
 
@@ -421,17 +429,7 @@ static int ibss_rsn_auth_init_group(struct ibss_rsn *ibss_rsn,
 	conf.eapol_version = 2;
 	conf.wpa_group_rekey = ssid->group_rekey ? ssid->group_rekey : 600;
 
-	os_memset(&cb, 0, sizeof(cb));
-	cb.ctx = ibss_rsn;
-	cb.logger = auth_logger;
-	cb.set_eapol = auth_set_eapol;
-	cb.send_eapol = auth_send_eapol;
-	cb.get_psk = auth_get_psk;
-	cb.set_key = auth_set_key;
-	cb.for_each_sta = auth_for_each_sta;
-	cb.disconnect = ibss_rsn_disconnect;
-
-	ibss_rsn->auth_group = wpa_init(own_addr, &conf, &cb);
+	ibss_rsn->auth_group = wpa_init(own_addr, &conf, &cb, ibss_rsn);
 	if (ibss_rsn->auth_group == NULL) {
 		wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
 		return -1;

wpa_supplicant/mesh_rsn.c

@@ -140,7 +140,12 @@ static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr,
 				enum mfp_options ieee80211w)
 {
 	struct wpa_auth_config conf;
-	struct wpa_auth_callbacks cb;
+	static const struct wpa_auth_callbacks cb = {
+		.logger = auth_logger,
+		.get_psk = auth_get_psk,
+		.set_key = auth_set_key,
+		.start_ampe = auth_start_ampe,
+	};
 	u8 seq[6] = {};
 
 	wpa_printf(MSG_DEBUG, "AUTH: Initializing group state machine");
@@ -159,14 +164,7 @@ static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr,
 		conf.group_mgmt_cipher = rsn->mgmt_group_cipher;
 #endif /* CONFIG_IEEE80211W */
 
-	os_memset(&cb, 0, sizeof(cb));
-	cb.ctx = rsn;
-	cb.logger = auth_logger;
-	cb.get_psk = auth_get_psk;
-	cb.set_key = auth_set_key;
-	cb.start_ampe = auth_start_ampe;
-
-	rsn->auth = wpa_init(addr, &conf, &cb);
+	rsn->auth = wpa_init(addr, &conf, &cb, rsn);
 	if (rsn->auth == NULL) {
 		wpa_printf(MSG_DEBUG, "AUTH: wpa_init() failed");
 		return -1;