Hello, recently we moved from a 4.9 kernel to 5.4 kernel and observed the following issue. To rule out that the issue was already fixed we then tried it with a 6.6 kernel and observed the same issue there, too. To sum it up, the following issue can be observed with kernel 5.4 and 6.6 but not with 4.9. We are using a Cisco AP with EWC (C9210) and EAP-PEAP as authentication method. Additionally, a session timeout is configured in the AP (300 s) after which a rekeying is taking place. So every 5 minutes a new four-way handshake is taking place which usually is completely encrypted. However, while sniffing with an external device we saw that the fourth packet of the four-way handshake is send unencrypted by our clients, when it comes to EAP-PEAP. The first three packets are encrypted as expected. In case of the Cisco AP the attempt is then rejected with a 4WAY_HANDSHAKE_TIMEOUT leading to a completely new authentication. On our clients we are using wpa_supplicant 2.10 with the same config on all kernels and therefore would rule out an issue in the supplicant, as it is working with the same supplicant in kernel 4.9. As driver we are using ath9k for QCA2066 (starting at kernel 4.9) and rtw88 for RTL8822CE (backported, starting at kernel 5.4). The issue exists for both drivers for kernel 5.4 and 6.6. Furthermore, we were also able to test a proprietary driver for the RTL8822CE chipset on kernel 5.4 where the issue does not appear. However, latter driver is a full-mac driver not using the mac80211 driver in comparison to the soft-mac drivers of the mainline. Considering all the details we highly assume that the issue is to be found in the mac80211 driver. Do you have some hints where to look at to solve the issue? Otherwise please let us know if we can provide some logs or config files. Thanks in advance Tobias Sperling
