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>
This commit is contained in:
Nick Lowe 2016-02-09 14:47:47 +00:00 committed by Jouni Malinen
parent f441e5af77
commit 98a516eae8
7 changed files with 36 additions and 16 deletions

View file

@ -1627,7 +1627,8 @@ const char * hostapd_wps_ap_pin_random(struct hostapd_data *hapd, int timeout)
unsigned int pin; unsigned int pin;
struct wps_ap_pin_data data; 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); os_snprintf(data.pin_txt, sizeof(data.pin_txt), "%08u", pin);
data.timeout = timeout; data.timeout = timeout;
hostapd_wps_for_each(hapd, wps_ap_pin_set, &data); hostapd_wps_for_each(hapd, wps_ap_pin_set, &data);

View file

@ -837,7 +837,7 @@ int wps_build_credential_wrap(struct wpabuf *msg,
unsigned int wps_pin_checksum(unsigned int pin); unsigned int wps_pin_checksum(unsigned int pin);
unsigned int wps_pin_valid(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); int wps_pin_str_valid(const char *pin);
void wps_free_pending_msgs(struct upnp_pending_message *msgs); void wps_free_pending_msgs(struct upnp_pending_message *msgs);

View file

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

View file

@ -915,7 +915,10 @@ int wpa_supplicant_ap_wps_pin(struct wpa_supplicant *wpa_s, const u8 *bssid,
return -1; return -1;
if (pin == NULL) { 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); ret_len = os_snprintf(buf, buflen, "%08d", rpin);
if (os_snprintf_error(buflen, ret_len)) if (os_snprintf_error(buflen, ret_len))
return -1; 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) if (wpa_s->ap_iface == NULL)
return NULL; return NULL;
hapd = wpa_s->ap_iface->bss[0]; 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_snprintf(pin_txt, sizeof(pin_txt), "%08u", pin);
os_free(hapd->conf->ap_pin); os_free(hapd->conf->ap_pin);
hapd->conf->ap_pin = os_strdup(pin_txt); hapd->conf->ap_pin = os_strdup(pin_txt);

View file

@ -956,7 +956,8 @@ static int wpa_supplicant_ctrl_iface_wps_pin(struct wpa_supplicant *wpa_s,
if (os_strcmp(cmd, "any") == 0) if (os_strcmp(cmd, "any") == 0)
_bssid = NULL; _bssid = NULL;
else if (os_strcmp(cmd, "get") == 0) { else if (os_strcmp(cmd, "get") == 0) {
ret = wps_generate_pin(); if (wps_generate_pin((unsigned int *) &ret) < 0)
return -1;
goto done; goto done;
} else if (hwaddr_aton(cmd, bssid)) { } else if (hwaddr_aton(cmd, bssid)) {
wpa_printf(MSG_DEBUG, "CTRL_IFACE WPS_PIN: invalid BSSID '%s'", wpa_printf(MSG_DEBUG, "CTRL_IFACE WPS_PIN: invalid BSSID '%s'",

View file

@ -2578,7 +2578,13 @@ static void wpas_prov_disc_req(void *ctx, const u8 *peer, u16 config_methods,
params[sizeof(params) - 1] = '\0'; params[sizeof(params) - 1] = '\0';
if (config_methods & WPS_CONFIG_DISPLAY) { 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, wpas_prov_disc_local_display(wpa_s, peer, params,
generated_pin); generated_pin);
} else if (config_methods & WPS_CONFIG_KEYPAD) } 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) if (config_methods & WPS_CONFIG_DISPLAY)
wpas_prov_disc_local_keypad(wpa_s, peer, params); wpas_prov_disc_local_keypad(wpa_s, peer, params);
else if (config_methods & WPS_CONFIG_KEYPAD) { 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, wpas_prov_disc_local_display(wpa_s, peer, params,
generated_pin); generated_pin);
} else if (config_methods & WPS_CONFIG_PUSHBUTTON) } 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) if (pin)
os_strlcpy(wpa_s->p2p_pin, pin, sizeof(wpa_s->p2p_pin)); os_strlcpy(wpa_s->p2p_pin, pin, sizeof(wpa_s->p2p_pin));
else if (wps_method == WPS_PIN_DISPLAY) { 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), res = os_snprintf(wpa_s->p2p_pin, sizeof(wpa_s->p2p_pin),
"%08d", ret); "%08d", ret);
if (os_snprintf_error(sizeof(wpa_s->p2p_pin), res)) if (os_snprintf_error(sizeof(wpa_s->p2p_pin), res))

View file

@ -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\"", os_snprintf(val, sizeof(val), "\"dev_pw_id=%u%s\"",
dev_pw_id, hash); dev_pw_id, hash);
} else { } 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\"", os_snprintf(val, sizeof(val), "\"pin=%08d dev_pw_id=%u%s\"",
rpin, dev_pw_id, hash); rpin, dev_pw_id, hash);
} }