WPS: Use only os_get_random() for PIN generation

Remove the fallback dependency on os_random() when generating a WPS pin.
This is exceptionally unlikely to ever be called as the call to
os_get_random() is unlikely to fail. The intention is to facilitate
future removal of os_random() as it uses a low quality PRNG.

Signed-off-by: Nick Lowe <nick.lowe@lugatech.com>

diff --git a/src/ap/wps_hostapd.c b/src/ap/wps_hostapd.c
index ba58f3e..faf38c9 100644 (file)
--- a/src/ap/wps_hostapd.c
+++ b/src/ap/wps_hostapd.c
@@ -1627,7 +1627,8 @@ const char * hostapd_wps_ap_pin_random(struct hostapd_data *hapd, int timeout)
        unsigned int pin;
        struct wps_ap_pin_data data;
 
-       pin = wps_generate_pin();
+       if (wps_generate_pin(&pin) < 0)
+               return NULL;
        os_snprintf(data.pin_txt, sizeof(data.pin_txt), "%08u", pin);
        data.timeout = timeout;
        hostapd_wps_for_each(hapd, wps_ap_pin_set, &data);

diff --git a/src/wps/wps.h b/src/wps/wps.h
index ff4dd10..2505d2d 100644 (file)
--- a/src/wps/wps.h
+++ b/src/wps/wps.h
@@ -837,7 +837,7 @@ int wps_build_credential_wrap(struct wpabuf *msg,
 
 unsigned int wps_pin_checksum(unsigned int pin);
 unsigned int wps_pin_valid(unsigned int pin);
-unsigned int wps_generate_pin(void);
+int wps_generate_pin(unsigned int *pin);
 int wps_pin_str_valid(const char *pin);
 void wps_free_pending_msgs(struct upnp_pending_message *msgs);
 

diff --git a/src/wps/wps_common.c b/src/wps/wps_common.c
index 88f85fe..c6a1cfd 100644 (file)
--- a/src/wps/wps_common.c
+++ b/src/wps/wps_common.c
@@ -235,20 +235,18 @@ unsigned int wps_pin_valid(unsigned int pin)
  * wps_generate_pin - Generate a random PIN
  * Returns: Eight digit PIN (i.e., including the checksum digit)
  */
-unsigned int wps_generate_pin(void)
+int wps_generate_pin(unsigned int *pin)
 {
        unsigned int val;
 
        /* Generate seven random digits for the PIN */
-       if (random_get_bytes((unsigned char *) &val, sizeof(val)) < 0) {
-               struct os_time now;
-               os_get_time(&now);
-               val = os_random() ^ now.sec ^ now.usec;
-       }
+       if (random_get_bytes((unsigned char *) &val, sizeof(val)) < 0)
+               return -1;
        val %= 10000000;
 
        /* Append checksum digit */
-       return val * 10 + wps_pin_checksum(val);
+       *pin = val * 10 + wps_pin_checksum(val);
+       return 0;
 }
 
 

diff --git a/wpa_supplicant/ap.c b/wpa_supplicant/ap.c
index 03c3fab..60f8c0d 100644 (file)
--- a/wpa_supplicant/ap.c
+++ b/wpa_supplicant/ap.c
@@ -915,7 +915,10 @@ int wpa_supplicant_ap_wps_pin(struct wpa_supplicant *wpa_s, const u8 *bssid,
                return -1;
 
        if (pin == NULL) {
-               unsigned int rpin = wps_generate_pin();
+               unsigned int rpin;
+
+               if (wps_generate_pin(&rpin) < 0)
+                       return -1;
                ret_len = os_snprintf(buf, buflen, "%08d", rpin);
                if (os_snprintf_error(buflen, ret_len))
                        return -1;
@@ -981,7 +984,8 @@ const char * wpas_wps_ap_pin_random(struct wpa_supplicant *wpa_s, int timeout)
        if (wpa_s->ap_iface == NULL)
                return NULL;
        hapd = wpa_s->ap_iface->bss[0];
-       pin = wps_generate_pin();
+       if (wps_generate_pin(&pin) < 0)
+               return NULL;
        os_snprintf(pin_txt, sizeof(pin_txt), "%08u", pin);
        os_free(hapd->conf->ap_pin);
        hapd->conf->ap_pin = os_strdup(pin_txt);

diff --git a/wpa_supplicant/ctrl_iface.c b/wpa_supplicant/ctrl_iface.c
index a377eb3..1057a84 100644 (file)
--- a/wpa_supplicant/ctrl_iface.c
+++ b/wpa_supplicant/ctrl_iface.c
@@ -956,7 +956,8 @@ static int wpa_supplicant_ctrl_iface_wps_pin(struct wpa_supplicant *wpa_s,
        if (os_strcmp(cmd, "any") == 0)
                _bssid = NULL;
        else if (os_strcmp(cmd, "get") == 0) {
-               ret = wps_generate_pin();
+               if (wps_generate_pin((unsigned int *) &ret) < 0)
+                       return -1;
                goto done;
        } else if (hwaddr_aton(cmd, bssid)) {
                wpa_printf(MSG_DEBUG, "CTRL_IFACE WPS_PIN: invalid BSSID '%s'",

diff --git a/wpa_supplicant/p2p_supplicant.c b/wpa_supplicant/p2p_supplicant.c
index bf8f394..4c54b46 100644 (file)
--- a/wpa_supplicant/p2p_supplicant.c
+++ b/wpa_supplicant/p2p_supplicant.c
@@ -2578,7 +2578,13 @@ static void wpas_prov_disc_req(void *ctx, const u8 *peer, u16 config_methods,
        params[sizeof(params) - 1] = '\0';
 
        if (config_methods & WPS_CONFIG_DISPLAY) {
-               generated_pin = wps_generate_pin();
+               if (wps_generate_pin(&generated_pin) < 0) {
+                       wpa_printf(MSG_DEBUG, "P2P: Could not generate PIN");
+                       wpas_notify_p2p_provision_discovery(
+                               wpa_s, peer, 0 /* response */,
+                               P2P_PROV_DISC_INFO_UNAVAILABLE, 0, 0);
+                       return;
+               }
                wpas_prov_disc_local_display(wpa_s, peer, params,
                                             generated_pin);
        } else if (config_methods & WPS_CONFIG_KEYPAD)
@@ -2623,7 +2629,13 @@ static void wpas_prov_disc_resp(void *ctx, const u8 *peer, u16 config_methods)
        if (config_methods & WPS_CONFIG_DISPLAY)
                wpas_prov_disc_local_keypad(wpa_s, peer, params);
        else if (config_methods & WPS_CONFIG_KEYPAD) {
-               generated_pin = wps_generate_pin();
+               if (wps_generate_pin(&generated_pin) < 0) {
+                       wpa_printf(MSG_DEBUG, "P2P: Could not generate PIN");
+                       wpas_notify_p2p_provision_discovery(
+                               wpa_s, peer, 0 /* response */,
+                               P2P_PROV_DISC_INFO_UNAVAILABLE, 0, 0);
+                       return;
+               }
                wpas_prov_disc_local_display(wpa_s, peer, params,
                                             generated_pin);
        } else if (config_methods & WPS_CONFIG_PUSHBUTTON)
@@ -5366,7 +5378,8 @@ int wpas_p2p_connect(struct wpa_supplicant *wpa_s, const u8 *peer_addr,
        if (pin)
                os_strlcpy(wpa_s->p2p_pin, pin, sizeof(wpa_s->p2p_pin));
        else if (wps_method == WPS_PIN_DISPLAY) {
-               ret = wps_generate_pin();
+               if (wps_generate_pin((unsigned int *) &ret) < 0)
+                       return -1;
                res = os_snprintf(wpa_s->p2p_pin, sizeof(wpa_s->p2p_pin),
                                  "%08d", ret);
                if (os_snprintf_error(sizeof(wpa_s->p2p_pin), res))

diff --git a/wpa_supplicant/wps_supplicant.c b/wpa_supplicant/wps_supplicant.c
index a39897d..07452ad 100644 (file)
--- a/wpa_supplicant/wps_supplicant.c
+++ b/wpa_supplicant/wps_supplicant.c
@@ -1236,7 +1236,10 @@ static int wpas_wps_start_dev_pw(struct wpa_supplicant *wpa_s,
                os_snprintf(val, sizeof(val), "\"dev_pw_id=%u%s\"",
                            dev_pw_id, hash);
        } else {
-               rpin = wps_generate_pin();
+               if (wps_generate_pin(&rpin) < 0) {
+                       wpa_printf(MSG_DEBUG, "WPS: Could not generate PIN");
+                       return -1;
+               }
                os_snprintf(val, sizeof(val), "\"pin=%08d dev_pw_id=%u%s\"",
                            rpin, dev_pw_id, hash);
        }