Password doesn't work

[SzymonDzw]

After turning on the Rover sometimes the WiFi password doesn't work. Works only after you wait some time or try multiple times.

[bjsowa]

Looking at the logs from hostapd it appears to be a problem with not enough entropy gained soon after boot of Raspberry Pi. It will reject first connections until it gains enough randomness for a secure WPA connection.

Here are systemd logs I got:

Dec 12 14:29:03 raspberrypi systemd[1]: Started LSB: Advanced IEEE 802.11 management daemon.
Dec 12 14:29:03 raspberrypi hostapd[618]: Configuration file: /etc/hostapd/hostapd.conf
Dec 12 14:29:04 raspberrypi hostapd[618]: Using interface wlan0ext with hwaddr 70:f1:1c:1e:26:43 and ssid "TurtleRover-XXYYY"
Dec 12 14:29:04 raspberrypi hostapd[618]: random: Cannot read from /dev/random: Resource temporarily unavailable
Dec 12 14:29:04 raspberrypi hostapd[618]: random: Only 0/20 bytes of strong random data available from /dev/random
Dec 12 14:29:04 raspberrypi hostapd[618]: random: Not enough entropy pool available for secure operations
Dec 12 14:29:04 raspberrypi hostapd[618]: WPA: Not enough entropy in random pool for secure operations - update keys later when the first station connects
Dec 12 14:29:04 raspberrypi hostapd[618]: wlan0ext: interface state UNINITIALIZED->ENABLED
Dec 12 14:29:04 raspberrypi hostapd[618]: wlan0ext: AP-ENABLED
Dec 12 14:29:07 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: authenticated
Dec 12 14:29:07 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: authenticated
Dec 12 14:29:07 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: associated (aid 1)
Dec 12 14:29:07 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: associated (aid 1)
Dec 12 14:29:07 raspberrypi hostapd[618]: random: Cannot read from /dev/random: Resource temporarily unavailable
Dec 12 14:29:07 raspberrypi hostapd[618]: random: Only 0/20 bytes of strong random data available from /dev/random
Dec 12 14:29:07 raspberrypi hostapd[618]: random: Not enough entropy pool available for secure operations
Dec 12 14:29:07 raspberrypi hostapd[618]: WPA: Not enough entropy in random pool to proceed - reject first 4-way handshake
Dec 12 14:29:10 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: authenticated
Dec 12 14:29:10 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: authenticated
Dec 12 14:29:10 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: associated (aid 1)
Dec 12 14:29:10 raspberrypi hostapd[618]: random: Cannot read from /dev/random: Resource temporarily unavailable
Dec 12 14:29:10 raspberrypi hostapd[618]: random: Only 0/20 bytes of strong random data available from /dev/random
Dec 12 14:29:10 raspberrypi hostapd[618]: random: Not enough entropy pool available for secure operations
Dec 12 14:29:10 raspberrypi hostapd[618]: WPA: Not enough entropy in random pool to proceed - reject first 4-way handshake
Dec 12 14:29:10 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: associated (aid 1)
Dec 12 14:29:13 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: authenticated
Dec 12 14:29:13 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: authenticated
Dec 12 14:29:13 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: associated (aid 1)
Dec 12 14:29:13 raspberrypi hostapd[618]: random: Cannot read from /dev/random: Resource temporarily unavailable
Dec 12 14:29:13 raspberrypi hostapd[618]: random: Only 0/20 bytes of strong random data available from /dev/random
Dec 12 14:29:13 raspberrypi hostapd[618]: random: Allow operation to proceed based on internal entropy
Dec 12 14:29:13 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 IEEE 802.11: associated (aid 1)
Dec 12 14:29:13 raspberrypi hostapd[618]: wlan0ext: AP-STA-CONNECTED 74:2f:68:dd:a1:13
Dec 12 14:29:13 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 RADIUS: starting accounting session 5C111B30-00000000
Dec 12 14:29:13 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 WPA: pairwise key handshake completed (RSN)
Dec 12 14:29:13 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 RADIUS: starting accounting session 5C111B30-00000000
Dec 12 14:29:13 raspberrypi hostapd[618]: wlan0ext: STA 74:2f:68:dd:a1:13 WPA: pairwise key handshake completed (RSN)

If it's not important problem I'll close the issue

[stsdc]

Well, then we should start AP after /dev/random becomes available.

[bjsowa]

This would extend the time needed to start hotspot as Hostapd uses rejected connections to gain more entropy faster.

[bjsowa]

I've read that Raspberry Pi has hardware random number generator that can be enabled and used to feed /dev/random so I'll try with that