brcmfmac: one faulty "iw interface add" command breaks in-firmware BSS state

brcmfmac: one faulty "iw interface add" command breaks in-firmware BSS state

[Rafał Miłecki]

[-- Attachment #1: Type: text/plain, Size: 4252 bytes --]

Hi,

I've discovered some bug in brcmfmac & its BSS management. It was
exposed by OpenWrt user space change ("fix") I introduced in:
http://git.openwrt.org/?p=openwrt.git;a=commit;h=1cbb5e8de50457c1d9724ca75cc6815df5721289
and it's related to the "interface add" command.

I've router with BCM43602 and I'm using a very recent brcmfmac.

brcmfmac 0000:01:00.0: enabling device (0140 -> 0142)
brcmfmac: brcmf_c_preinit_dcmds: Firmware version = wl0: Mar  3 2015
04:46:51 version 7.35.177.33 (r538052) FWID 01-c8317c80
brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code

wlan0     Link encap:Ethernet  HWaddr 00:23:6A:A3:7D:95
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:8 errors:0 dropped:4 overruns:0 frame:0
          TX packets:19 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:505 (505.0 B)  TX bytes:1730 (1.6 KiB)

I'll just describe two scenarios that should make things clear. Both
after a cold boot.


1) Standard (working) scenario
# hostapd /etc/hostapd.conf
Configuration file: /etc/hostapd.conf
Failed to create interface mon.wlan0: -95 (Operation not supported)
[  105.483797] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
[  105.490308] brcmfmac: brcmf_add_if: ignore IF event
[  105.499067] device wlan0 entered promiscuous mode
[  105.503939] br-lan: port 2(wlan0) entered forwarding state
[  105.509437] br-lan: port 2(wlan0) entered forwarding state
wlan0: Could not connect to kernel driver
Using interface wlan0 with hwaddr 00:23:6a:a3:7d:95 and ssid "OpenWrtA"
[  105.640966] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
[  105.647478] brcmfmac: brcmf_add_if: ignore IF event
wlan0: interface state UNINITIALIZED->ENABLED
wlan0: AP-ENABLED
[  107.510613] br-lan: port 2(wlan0) entered forwarding state

This results in a working AP, my devices are able to connect


2) Scenario with iw command "mistake":
# iw phy phy0 interface add wlan0 type __ap
[   65.036358] brcmfmac: brcmf_net_attach: couldn't register the net device
[   65.043080] brcmfmac: brcmf_ap_add_vif: Registering netdevice failed
command failed: Invalid exchange (-52)
# hostapd /etc/hostapd.conf
Configuration file: /etc/hostapd.conf
Failed to create interface mon.wlan0: -95 (Operation not supported)
[   83.393594] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
[   83.400122] brcmfmac: brcmf_add_if: ignore IF event
[   83.409448] device wlan0 entered promiscuous mode
[   83.414259] br-lan: port 2(wlan0) entered forwarding state
[   83.419802] br-lan: port 2(wlan0) entered forwarding state
wlan0: Could not connect to kernel driver
Using interface wlan0 with hwaddr 00:23:6a:a3:7d:95 and ssid "OpenWrtA"
[   83.550307] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
[   83.556814] brcmfmac: brcmf_add_if: ignore IF event
wlan0: interface state UNINITIALIZED->ENABLED
wlan0: AP-ENABLED
[   85.418417] br-lan: port 2(wlan0) entered forwarding state

In this case in-firmware BSS state seems to be broken and BSS seems to
be using *different* address. Following wpa_supplicant log should make
it clear.

wlp2s0b1: State: SCANNING -> AUTHENTICATING
EAPOL: External notification - EAP success=0
EAPOL: Supplicant port status: Unauthorized
EAPOL: External notification - EAP fail=0
EAPOL: Supplicant port status: Unauthorized
EAPOL: External notification - portControl=Auto
EAPOL: Supplicant port status: Unauthorized
nl80211: Authenticate (ifindex=3)
  * bssid=00:23:6a:a3:7d:95
  * freq=2462
  * SSID - hexdump_ascii(len=8):
     4f 70 65 6e 57 72 74 41                           OpenWrtA
  * IEs - hexdump(len=0): [NULL]
  * Auth Type 0
nl80211: Authentication request send successfully
RSN: Ignored PMKID candidate without preauth flag
nl80211: Event message available
nl80211: New station 00:23:6a:a3:7d:95
nl80211: Event message available
nl80211: MLME event 37
nl80211: Authenticate event
wlp2s0b1: Event AUTH (11) received
wlp2s0b1: SME: Ignore authentication with unexpected peer 02:23:6a:a3:7d:96
wlp2s0b1: SME: Authentication timeout
wpa_driver_nl80211_deauthenticate(addr=00:23:6a:a3:7d:95 reason_code=3)

-- 
Rafał

[-- Attachment #2: hostapd.conf --]
[-- Type: application/octet-stream, Size: 496 bytes --]

driver=nl80211
logger_syslog=127
logger_syslog_level=2
logger_stdout=127
logger_stdout_level=2
hw_mode=g
channel=11
noscan=1
ieee80211n=1
ht_coex=0
ht_capab=[SHORT-GI-20][DSSS_CCK-40]

interface=wlan0
ctrl_interface=/var/run/hostapd
disassoc_low_ack=1
preamble=1
wmm_enabled=1
ignore_broadcast_ssid=0
uapsd_advertisement_enabled=1
wpa_passphrase=openwrt123
auth_algs=1
wpa=2
wpa_pairwise=CCMP
ssid=OpenWrtA
bridge=br-lan
wpa_key_mgmt=WPA-PSK
okc=0
disable_pmksa_caching=1
bssid=00:23:6a:a3:7d:95

Re: brcmfmac: one faulty "iw interface add" command breaks in-firmware BSS state

[Arend van Spriel]

On 06/21/15 21:59, Rafał Miłecki wrote:
> Hi,
>
> I've discovered some bug in brcmfmac&  its BSS management. It was
> exposed by OpenWrt user space change ("fix") I introduced in:
> http://git.openwrt.org/?p=openwrt.git;a=commit;h=1cbb5e8de50457c1d9724ca75cc6815df5721289
> and it's related to the "interface add" command.
>
> I've router with BCM43602 and I'm using a very recent brcmfmac.
>
> brcmfmac 0000:01:00.0: enabling device (0140 ->  0142)
> brcmfmac: brcmf_c_preinit_dcmds: Firmware version = wl0: Mar  3 2015
> 04:46:51 version 7.35.177.33 (r538052) FWID 01-c8317c80
> brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code
>
> wlan0     Link encap:Ethernet  HWaddr 00:23:6A:A3:7D:95
>            BROADCAST MULTICAST  MTU:1500  Metric:1
>            RX packets:8 errors:0 dropped:4 overruns:0 frame:0
>            TX packets:19 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:1000
>            RX bytes:505 (505.0 B)  TX bytes:1730 (1.6 KiB)
>
> I'll just describe two scenarios that should make things clear. Both
> after a cold boot.
>
>
> 1) Standard (working) scenario
> # hostapd /etc/hostapd.conf
> Configuration file: /etc/hostapd.conf
> Failed to create interface mon.wlan0: -95 (Operation not supported)
> [  105.483797] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
> [  105.490308] brcmfmac: brcmf_add_if: ignore IF event
> [  105.499067] device wlan0 entered promiscuous mode
> [  105.503939] br-lan: port 2(wlan0) entered forwarding state
> [  105.509437] br-lan: port 2(wlan0) entered forwarding state
> wlan0: Could not connect to kernel driver
> Using interface wlan0 with hwaddr 00:23:6a:a3:7d:95 and ssid "OpenWrtA"
> [  105.640966] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
> [  105.647478] brcmfmac: brcmf_add_if: ignore IF event
> wlan0: interface state UNINITIALIZED->ENABLED
> wlan0: AP-ENABLED
> [  107.510613] br-lan: port 2(wlan0) entered forwarding state
>
> This results in a working AP, my devices are able to connect
>
>
> 2) Scenario with iw command "mistake":
> # iw phy phy0 interface add wlan0 type __ap

Now this is a pretty silly scenario as there already is a wlan0 
interface. Admittedly, this should be rejected as such. This clearly is 
a user mistake (not sure why you quoted that :-p ) and it might be good 
to catch this in cfg80211 as it probably applies to other drivers as 
well. This probably explains why register_netdev fails.

Regards,
Arend

> [   65.036358] brcmfmac: brcmf_net_attach: couldn't register the net device
> [   65.043080] brcmfmac: brcmf_ap_add_vif: Registering netdevice failed
> command failed: Invalid exchange (-52)
> # hostapd /etc/hostapd.conf
> Configuration file: /etc/hostapd.conf
> Failed to create interface mon.wlan0: -95 (Operation not supported)
> [   83.393594] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
> [   83.400122] brcmfmac: brcmf_add_if: ignore IF event
> [   83.409448] device wlan0 entered promiscuous mode
> [   83.414259] br-lan: port 2(wlan0) entered forwarding state
> [   83.419802] br-lan: port 2(wlan0) entered forwarding state
> wlan0: Could not connect to kernel driver
> Using interface wlan0 with hwaddr 00:23:6a:a3:7d:95 and ssid "OpenWrtA"
> [   83.550307] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
> [   83.556814] brcmfmac: brcmf_add_if: ignore IF event
> wlan0: interface state UNINITIALIZED->ENABLED
> wlan0: AP-ENABLED
> [   85.418417] br-lan: port 2(wlan0) entered forwarding state
>
> In this case in-firmware BSS state seems to be broken and BSS seems to
> be using *different* address. Following wpa_supplicant log should make
> it clear.

Well, you now have a STA and AP interface in firmware, but only STA 
netdev so the AP interface is pretty useless. I am not sure about the 
mac address, but I think it is expected. Otherwise you would have two 
interfaces with the same mac address.

Regards,
Arend

> wlp2s0b1: State: SCANNING ->  AUTHENTICATING
> EAPOL: External notification - EAP success=0
> EAPOL: Supplicant port status: Unauthorized
> EAPOL: External notification - EAP fail=0
> EAPOL: Supplicant port status: Unauthorized
> EAPOL: External notification - portControl=Auto
> EAPOL: Supplicant port status: Unauthorized
> nl80211: Authenticate (ifindex=3)
>    * bssid=00:23:6a:a3:7d:95
>    * freq=2462
>    * SSID - hexdump_ascii(len=8):
>       4f 70 65 6e 57 72 74 41                           OpenWrtA
>    * IEs - hexdump(len=0): [NULL]
>    * Auth Type 0
> nl80211: Authentication request send successfully
> RSN: Ignored PMKID candidate without preauth flag
> nl80211: Event message available
> nl80211: New station 00:23:6a:a3:7d:95
> nl80211: Event message available
> nl80211: MLME event 37
> nl80211: Authenticate event
> wlp2s0b1: Event AUTH (11) received
> wlp2s0b1: SME: Ignore authentication with unexpected peer 02:23:6a:a3:7d:96
> wlp2s0b1: SME: Authentication timeout
> wpa_driver_nl80211_deauthenticate(addr=00:23:6a:a3:7d:95 reason_code=3)
>

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Re: brcmfmac: one faulty "iw interface add" command breaks in-firmware BSS state

[Johannes Berg]

On Mon, 2015-06-22 at 09:47 +0200, Arend van Spriel wrote:

> > # iw phy phy0 interface add wlan0 type __ap
> 
> Now this is a pretty silly scenario as there already is a wlan0 
> interface. Admittedly, this should be rejected as such. This clearly is 
> a user mistake (not sure why you quoted that :-p ) and it might be good 
> to catch this in cfg80211 as it probably applies to other drivers as 
> well. This probably explains why register_netdev fails.

I don't think that's easy to catch - but the driver really should just
see that register_netdev fails and do nothing (except for reporting the
error back), no?

johannes

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Re: brcmfmac: one faulty "iw interface add" command breaks in-firmware BSS state

[Rafał Miłecki]

On 22 June 2015 at 09:47, Arend van Spriel <arend@broadcom.com> wrote:
> On 06/21/15 21:59, Rafał Miłecki wrote:
>> I've discovered some bug in brcmfmac&  its BSS management. It was
>>
>> exposed by OpenWrt user space change ("fix") I introduced in:
>>
>> http://git.openwrt.org/?p=openwrt.git;a=commit;h=1cbb5e8de50457c1d9724ca75cc6815df5721289
>> and it's related to the "interface add" command.
>>
>> I've router with BCM43602 and I'm using a very recent brcmfmac.
>>
>> brcmfmac 0000:01:00.0: enabling device (0140 ->  0142)
>> brcmfmac: brcmf_c_preinit_dcmds: Firmware version = wl0: Mar  3 2015
>> 04:46:51 version 7.35.177.33 (r538052) FWID 01-c8317c80
>> brcmfmac: brcmf_cfg80211_reg_notifier: not a ISO3166 code
>>
>> wlan0     Link encap:Ethernet  HWaddr 00:23:6A:A3:7D:95
>>            BROADCAST MULTICAST  MTU:1500  Metric:1
>>            RX packets:8 errors:0 dropped:4 overruns:0 frame:0
>>            TX packets:19 errors:0 dropped:0 overruns:0 carrier:0
>>            collisions:0 txqueuelen:1000
>>            RX bytes:505 (505.0 B)  TX bytes:1730 (1.6 KiB)
>>
>> I'll just describe two scenarios that should make things clear. Both
>> after a cold boot.
>>
>>
>> 1) Standard (working) scenario
>> # hostapd /etc/hostapd.conf
>> Configuration file: /etc/hostapd.conf
>> Failed to create interface mon.wlan0: -95 (Operation not supported)
>> [  105.483797] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
>> [  105.490308] brcmfmac: brcmf_add_if: ignore IF event
>> [  105.499067] device wlan0 entered promiscuous mode
>> [  105.503939] br-lan: port 2(wlan0) entered forwarding state
>> [  105.509437] br-lan: port 2(wlan0) entered forwarding state
>> wlan0: Could not connect to kernel driver
>> Using interface wlan0 with hwaddr 00:23:6a:a3:7d:95 and ssid "OpenWrtA"
>> [  105.640966] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
>> [  105.647478] brcmfmac: brcmf_add_if: ignore IF event
>> wlan0: interface state UNINITIALIZED->ENABLED
>> wlan0: AP-ENABLED
>> [  107.510613] br-lan: port 2(wlan0) entered forwarding state
>>
>> This results in a working AP, my devices are able to connect
>>
>>
>> 2) Scenario with iw command "mistake":
>> # iw phy phy0 interface add wlan0 type __ap
>
>
> Now this is a pretty silly scenario as there already is a wlan0 interface.
> Admittedly, this should be rejected as such. This clearly is a user mistake
> (not sure why you quoted that :-p ) and it might be good to catch this in
> cfg80211 as it probably applies to other drivers as well. This probably
> explains why register_netdev fails.

To tell the truth, it's part of bigger OpenWrt script. To make things
clean, on every configuration change, OpenWrt removes all interfaces
and (re)creates needed ones. Unfortunately brcmfmac doesn't allow
removing wlan0 and it results in OpenWrt trying to create wlan0 that
wasn't previously removed.


>> [   65.036358] brcmfmac: brcmf_net_attach: couldn't register the net
>> device
>> [   65.043080] brcmfmac: brcmf_ap_add_vif: Registering netdevice failed
>> command failed: Invalid exchange (-52)
>> # hostapd /etc/hostapd.conf
>> Configuration file: /etc/hostapd.conf
>> Failed to create interface mon.wlan0: -95 (Operation not supported)
>> [   83.393594] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
>> [   83.400122] brcmfmac: brcmf_add_if: ignore IF event
>> [   83.409448] device wlan0 entered promiscuous mode
>> [   83.414259] br-lan: port 2(wlan0) entered forwarding state
>> [   83.419802] br-lan: port 2(wlan0) entered forwarding state
>> wlan0: Could not connect to kernel driver
>> Using interface wlan0 with hwaddr 00:23:6a:a3:7d:95 and ssid "OpenWrtA"
>> [   83.550307] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
>> [   83.556814] brcmfmac: brcmf_add_if: ignore IF event
>> wlan0: interface state UNINITIALIZED->ENABLED
>> wlan0: AP-ENABLED
>> [   85.418417] br-lan: port 2(wlan0) entered forwarding state
>>
>> In this case in-firmware BSS state seems to be broken and BSS seems to
>> be using *different* address. Following wpa_supplicant log should make
>> it clear.
>
>
> Well, you now have a STA and AP interface in firmware, but only STA netdev
> so the AP interface is pretty useless. I am not sure about the mac address,
> but I think it is expected. Otherwise you would have two interfaces with the
> same mac address.

wlan0 is still visible as it was before calling faulty iw command.
If brcmfmac assigned different in-firmware BSS to the wlan0 we end up
with inconsistent state. We now have STA (wlan0) vs. AP (in-firmware)
and 00:23:6a:a3:7d:95 (wlan0) vs. 02:23:6a:a3:7d:96 (in-firmware).
So it's clearly not something brcmfmac should do.

-- 
Rafał
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Re: brcmfmac: one faulty "iw interface add" command breaks in-firmware BSS state

[Arend van Spriel]

On 06/22/15 10:03, Johannes Berg wrote:
> On Mon, 2015-06-22 at 09:47 +0200, Arend van Spriel wrote:
>
>>> # iw phy phy0 interface add wlan0 type __ap
>>
>> Now this is a pretty silly scenario as there already is a wlan0
>> interface. Admittedly, this should be rejected as such. This clearly is
>> a user mistake (not sure why you quoted that :-p ) and it might be good
>> to catch this in cfg80211 as it probably applies to other drivers as
>> well. This probably explains why register_netdev fails.
>
> I don't think that's easy to catch - but the driver really should just
> see that register_netdev fails and do nothing (except for reporting the
> error back), no?

Indeed there is an issue with error handling here, but as this was a 
user fault I was looking for early detection. If as you say that will 
not be easy from cfg80211 we will need to rework brcmfmac code. 
Currently, we create interface in firmware and upon receiving 'ifc 
created' event we do the register_netdev. I think we do that to avoid 
getting start_xmit calls as we do not use netif carrier calls.

Regards,
Arend
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Re: brcmfmac: one faulty "iw interface add" command breaks in-firmware BSS state

[Johannes Berg]

On Mon, 2015-06-22 at 10:20 +0200, Arend van Spriel wrote:

> >>> # iw phy phy0 interface add wlan0 type __ap

> Indeed there is an issue with error handling here, but as this was a 
> user fault I was looking for early detection. If as you say that will 
> not be easy from cfg80211 we will need to rework brcmfmac code. 
> Currently, we create interface in firmware and upon receiving 'ifc 
> created' event we do the register_netdev. I think we do that to avoid 
> getting start_xmit calls as we do not use netif carrier calls.

We could possibly check for duplicate names, but surely there are other
failure modes that we can't easily pre-check, so it seems better to fix
the driver (and, in fact, use the duplicate name issue as a convenient
way of testing the error path)

johannes

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Re: brcmfmac: one faulty "iw interface add" command breaks in-firmware BSS state

[Rafał Miłecki]

On 21 June 2015 at 21:59, Rafał Miłecki <zajec5@gmail.com> wrote:
> I've discovered some bug in brcmfmac & its BSS management. It was
> exposed by OpenWrt user space change ("fix") I introduced in:
> http://git.openwrt.org/?p=openwrt.git;a=commit;h=1cbb5e8de50457c1d9724ca75cc6815df5721289
> and it's related to the "interface add" command.

Did you try to fix it? I really would love to have upcoming OpenWrt CC
release with a working brcmfmac.