Encryption problems with nl80211

[Dan Williams]

On Tue, 2015-10-27 at 18:16 +0100, simo wrote:
> Hi, I am Simon and I am new in this mail list.
> 
> I am experiencing problems enabling encryption key after creating an
> IBSS network through wpa_supplicant.

It looks like the error is coming from the kernel mac80211/cfg80211 WiFi
stack in nl80211_key_allowed().  That function returns an error if there
is not yet any "current_bss", which is probably the case here.  To me it
looks like a mismatch in expectations between the kernel and
wpa_supplicant about how IBSS WEP is supposed to be configured.

wpas_start_assoc_cb() - sets up parameters for IBSS create/join
-- kernel cfg80211 has current_bss = NULL
wpas_start_assoc_cb() calls wpa_set_wep_keys()
-- kernel cfg80211 rejects set_keys request because current_bss == NULL
wpas_start_assoc_cb() calls wpa_drv_associate() to being association
-- kernel driver creates new IBSS, sends EVENT_IBSS_JOINED
-- kernel cfg80211 calls __cfg80211_ibss_joined() and sets current_bss

What's odd is that none of this code in the kernel or supplicant has
really changed since early 2013, so its either been broken for a long
time, or I'm missing something completely about when current_bss gets
set.

Dan

> wlan0: Trying to associate with SSID 'my-net-302'
> wlan0: Cancelling scan request
> wlan0: WPA: clearing own WPA/RSN IE
> wlan0: Automatic auth_alg selection: 0x1
> wlan0: WPA: clearing AP WPA IE
> wlan0: WPA: clearing AP RSN IE
> wlan0: WPA: clearing own WPA/RSN IE
> wpa_driver_nl80211_set_key: ifindex=3 (wlan0) alg=1 addr=(nil) key_idx=0
> set_tx=1 seq_len=0 key_len=5
> nl80211: KEY_DATA - hexdump(len=5): [REMOVED]
> nl80211: set_key failed; err=-67 Link has been severed)

^^^ the error
<snip>

> nl80211: Event message available
> nl80211: Drv Event 43 (NL80211_CMD_JOIN_IBSS) received for wlan0
> nl80211: IBSS 12:24:21:59:87:d0 joined
> nl80211: IBSS-joined on 2412 MHz
> nl80211: Operating frequency for the associated BSS from scan results:
> 2412 MHz
> nl80211: IBSS on frequency 2412 MHz
> wlan0: Event ASSOC (0) received
> wlan0: State: ASSOCIATING -> ASSOCIATED

Then reports success creating/joining the adhoc network.  But of course,
since the key set failed, the network is not encrypted.

Dan