[PATCH 02/10] Remove the fallback dependency on os_random() when generating a WPS pin
Nick Lowe
nick.lowe at lugatech.com
Sun Feb 14 11:34:05 PST 2016
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 exceptionally 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 at lugatech.com>
---
src/ap/wps_hostapd.c | 3 ++-
src/wps/wps.h | 2 +-
src/wps/wps_common.c | 9 ++++-----
wpa_supplicant/ap.c | 7 +++++--
wpa_supplicant/ctrl_iface.c | 3 ++-
wpa_supplicant/p2p_supplicant.c | 17 ++++++++++++++---
wpa_supplicant/wps_supplicant.c | 5 ++++-
7 files changed, 32 insertions(+), 14 deletions(-)
diff --git a/src/ap/wps_hostapd.c b/src/ap/wps_hostapd.c
index ba58f3e..faf38c9 100644
--- 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
--- 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..1ee9eb9 100644
--- a/src/wps/wps_common.c
+++ b/src/wps/wps_common.c
@@ -235,20 +235,19 @@ 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;
+ 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 98b9596..1a0fbc4 100644
--- a/wpa_supplicant/ap.c
+++ b/wpa_supplicant/ap.c
@@ -913,7 +913,9 @@ 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;
@@ -979,7 +981,8 @@ 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 b3d6246..7a6f4c9 100644
--- 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(&pin) < 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 9b36b63..2de45a9 100644
--- a/wpa_supplicant/p2p_supplicant.c
+++ b/wpa_supplicant/p2p_supplicant.c
@@ -2576,7 +2576,12 @@ 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)
@@ -2621,7 +2626,12 @@ 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)
@@ -5364,7 +5374,8 @@ 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(&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 5c674b2..098d4c2 100644
--- a/wpa_supplicant/wps_supplicant.c
+++ b/wpa_supplicant/wps_supplicant.c
@@ -1228,7 +1228,10 @@ 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);
}
--
2.5.0
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