[PATCH wireless v2] nl80211/cfg80211: add nla_policy for S1G band

[PATCH wireless v2] nl80211/cfg80211: add nla_policy for S1G band

[Lin Ma]

Our detector has identified another case of an incomplete policy.
Specifically, the commit df78a0c0b67d ("nl80211: S1G band and channel
definitions") introduced the NL80211_BAND_S1GHZ attribute to
nl80211_band, but it neglected to update the
nl80211_match_band_rssi_policy accordingly.

Similar commits that add new band types, such as the initial
commit 1e1b11b6a111 ("nl80211/cfg80211: Specify band specific min RSSI
thresholds with sched scan"), the commit e548a1c36b11 ("cfg80211: add 6GHz
in code handling array with NUM_NL80211_BANDS entries"), and the
commit 63fa04266629 ("nl80211: Add LC placeholder band definition to
nl80211_band"), all require updates to the policy.
Failure to do so could result in accessing an attribute of unexpected
length in the function nl80211_parse_sched_scan_per_band_rssi.

To resolve this issue, this commit adds the policy for the
NL80211_BAND_S1GHZ attribute.

Fixes: df78a0c0b67d ("nl80211: S1G band and channel definitions")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
---
V1 -> V2: change net-next to wireless as suggested

 net/wireless/nl80211.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 60877b532993..980300621a60 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -911,6 +911,7 @@ nl80211_match_band_rssi_policy[NUM_NL80211_BANDS] = {
 	[NL80211_BAND_5GHZ] = { .type = NLA_S32 },
 	[NL80211_BAND_6GHZ] = { .type = NLA_S32 },
 	[NL80211_BAND_60GHZ] = { .type = NLA_S32 },
+	[NL80211_BAND_S1GHZ] = { .type = NLA_S32 },
 	[NL80211_BAND_LC]    = { .type = NLA_S32 },
 };
 
-- 
2.34.1

Re: [PATCH wireless v2] nl80211/cfg80211: add nla_policy for S1G band

[Johannes Berg]

On Fri, 2024-01-19 at 23:12 +0800, Lin Ma wrote:
> 
> V1 -> V2: change net-next to wireless as suggested

For the record, I don't think anyone is using scheduled scan with S1G or
even _could_ be doing that (is there even a driver other than hwsim?),
so I don't think I'll apply this for wireless. No need to resend (again)
though :)

johannes

Re: [PATCH wireless v2] nl80211/cfg80211: add nla_policy for S1G band

[Jeff Johnson]

On 1/19/2024 7:12 AM, Lin Ma wrote:
> Our detector has identified another case of an incomplete policy.
> Specifically, the commit df78a0c0b67d ("nl80211: S1G band and channel
> definitions") introduced the NL80211_BAND_S1GHZ attribute to
> nl80211_band, but it neglected to update the
> nl80211_match_band_rssi_policy accordingly.
> 
> Similar commits that add new band types, such as the initial
> commit 1e1b11b6a111 ("nl80211/cfg80211: Specify band specific min RSSI
> thresholds with sched scan"), the commit e548a1c36b11 ("cfg80211: add 6GHz
> in code handling array with NUM_NL80211_BANDS entries"), and the
> commit 63fa04266629 ("nl80211: Add LC placeholder band definition to
> nl80211_band"), all require updates to the policy.
> Failure to do so could result in accessing an attribute of unexpected
> length in the function nl80211_parse_sched_scan_per_band_rssi.
> 
> To resolve this issue, this commit adds the policy for the
> NL80211_BAND_S1GHZ attribute.
> 
> Fixes: df78a0c0b67d ("nl80211: S1G band and channel definitions")
> Signed-off-by: Lin Ma <linma@zju.edu.cn>
> ---
> V1 -> V2: change net-next to wireless as suggested
> 
>  net/wireless/nl80211.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index 60877b532993..980300621a60 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -911,6 +911,7 @@ nl80211_match_band_rssi_policy[NUM_NL80211_BANDS] = {
>  	[NL80211_BAND_5GHZ] = { .type = NLA_S32 },
>  	[NL80211_BAND_6GHZ] = { .type = NLA_S32 },
>  	[NL80211_BAND_60GHZ] = { .type = NLA_S32 },
> +	[NL80211_BAND_S1GHZ] = { .type = NLA_S32 },
>  	[NL80211_BAND_LC]    = { .type = NLA_S32 },
>  };
>  
something is really suspicious since the NL80211_BAND_* enums are
*value* enums, not attribute ID enums, and hence they should never be
used in an nla_policy.

what is actually using these as attribute IDs, noting that
NL80211_BAND_2GHZ == 0 and hence cannot be used as an attribute ID

seems the logic that introduced this policy needs to be revisited.

Re: [PATCH wireless v2] nl80211/cfg80211: add nla_policy for S1G band

[Johannes Berg]

On Fri, 2024-01-19 at 15:47 -0800, Jeff Johnson wrote:
> > --- a/net/wireless/nl80211.c
> > +++ b/net/wireless/nl80211.c
> > @@ -911,6 +911,7 @@ nl80211_match_band_rssi_policy[NUM_NL80211_BANDS] = {
> >  	[NL80211_BAND_5GHZ] = { .type = NLA_S32 },
> >  	[NL80211_BAND_6GHZ] = { .type = NLA_S32 },
> >  	[NL80211_BAND_60GHZ] = { .type = NLA_S32 },
> > +	[NL80211_BAND_S1GHZ] = { .type = NLA_S32 },
> >  	[NL80211_BAND_LC]    = { .type = NLA_S32 },
> >  };
> >  
> something is really suspicious since the NL80211_BAND_* enums are
> *value* enums, not attribute ID enums, and hence they should never be
> used in an nla_policy.

Yeah, that's what it looks like first, but then they do get used
anyway...

> what is actually using these as attribute IDs, noting that
> NL80211_BAND_2GHZ == 0 and hence cannot be used as an attribute ID

Ohh. Good catch!

> seems the logic that introduced this policy needs to be revisited.
> 

Let's just remove it?

commit 1e1b11b6a1111cd9e8af1fd6ccda270a9fa3eacf
Author: vamsi krishna <vamsin@codeaurora.org>
Date:   Fri Feb 1 18:34:51 2019 +0530

    nl80211/cfg80211: Specify band specific min RSSI thresholds with sched scan


As far as I can tell nothing is using that in the first place ...
Certainly not in the kernel, nor wpa_s, nor anything else I could find
really ...

We can't completely revert it since we need the attribute number to stay
allocated, but that's all we cannot remove.

johannes

Re: [PATCH wireless v2] nl80211/cfg80211: add nla_policy for S1G band

[Jeff Johnson]

On 1/20/2024 12:27 PM, Johannes Berg wrote:
> On Fri, 2024-01-19 at 15:47 -0800, Jeff Johnson wrote:
>>> --- a/net/wireless/nl80211.c
>>> +++ b/net/wireless/nl80211.c
>>> @@ -911,6 +911,7 @@ nl80211_match_band_rssi_policy[NUM_NL80211_BANDS] = {
>>>  	[NL80211_BAND_5GHZ] = { .type = NLA_S32 },
>>>  	[NL80211_BAND_6GHZ] = { .type = NLA_S32 },
>>>  	[NL80211_BAND_60GHZ] = { .type = NLA_S32 },
>>> +	[NL80211_BAND_S1GHZ] = { .type = NLA_S32 },
>>>  	[NL80211_BAND_LC]    = { .type = NLA_S32 },
>>>  };
>>>  
>> something is really suspicious since the NL80211_BAND_* enums are
>> *value* enums, not attribute ID enums, and hence they should never be
>> used in an nla_policy.
> 
> Yeah, that's what it looks like first, but then they do get used
> anyway...
> 
>> what is actually using these as attribute IDs, noting that
>> NL80211_BAND_2GHZ == 0 and hence cannot be used as an attribute ID
> 
> Ohh. Good catch!
> 
>> seems the logic that introduced this policy needs to be revisited.
>>
> 
> Let's just remove it?
> 
> commit 1e1b11b6a1111cd9e8af1fd6ccda270a9fa3eacf
> Author: vamsi krishna <vamsin@codeaurora.org>
> Date:   Fri Feb 1 18:34:51 2019 +0530
> 
>     nl80211/cfg80211: Specify band specific min RSSI thresholds with sched scan
> 
> 
> As far as I can tell nothing is using that in the first place ...
> Certainly not in the kernel, nor wpa_s, nor anything else I could find
> really ...
> 
> We can't completely revert it since we need the attribute number to stay
> allocated, but that's all we cannot remove.

I'm investigating this and will report back.

Re: [PATCH wireless v2] nl80211/cfg80211: add nla_policy for S1G band

[Jeff Johnson]

On 1/22/2024 10:33 AM, Jeff Johnson wrote:
> On 1/20/2024 12:27 PM, Johannes Berg wrote:
>> On Fri, 2024-01-19 at 15:47 -0800, Jeff Johnson wrote:
>>>> --- a/net/wireless/nl80211.c
>>>> +++ b/net/wireless/nl80211.c
>>>> @@ -911,6 +911,7 @@ nl80211_match_band_rssi_policy[NUM_NL80211_BANDS] = {
>>>>  	[NL80211_BAND_5GHZ] = { .type = NLA_S32 },
>>>>  	[NL80211_BAND_6GHZ] = { .type = NLA_S32 },
>>>>  	[NL80211_BAND_60GHZ] = { .type = NLA_S32 },
>>>> +	[NL80211_BAND_S1GHZ] = { .type = NLA_S32 },
>>>>  	[NL80211_BAND_LC]    = { .type = NLA_S32 },
>>>>  };
>>>>  
>>> something is really suspicious since the NL80211_BAND_* enums are
>>> *value* enums, not attribute ID enums, and hence they should never be
>>> used in an nla_policy.
>>
>> Yeah, that's what it looks like first, but then they do get used
>> anyway...
>>
>>> what is actually using these as attribute IDs, noting that
>>> NL80211_BAND_2GHZ == 0 and hence cannot be used as an attribute ID
>>
>> Ohh. Good catch!
>>
>>> seems the logic that introduced this policy needs to be revisited.
>>>
>>
>> Let's just remove it?
>>
>> commit 1e1b11b6a1111cd9e8af1fd6ccda270a9fa3eacf
>> Author: vamsi krishna <vamsin@codeaurora.org>
>> Date:   Fri Feb 1 18:34:51 2019 +0530
>>
>>     nl80211/cfg80211: Specify band specific min RSSI thresholds with sched scan
>>
>>
>> As far as I can tell nothing is using that in the first place ...
>> Certainly not in the kernel, nor wpa_s, nor anything else I could find
>> really ...
>>
>> We can't completely revert it since we need the attribute number to stay
>> allocated, but that's all we cannot remove.
> 
> I'm investigating this and will report back.

OK, I have investigated this and based upon the investigation this can
be removed (except for keeping the now obsolete uapi bits). This was
done in preparation for supporting a new Android interface in the
out-of-tree Android driver, but that interface was subsequently
withdrawn by Google.

Johannes, do you want to handle this? Or should I?

/jeff

Re: [PATCH wireless v2] nl80211/cfg80211: add nla_policy for S1G band

[Johannes Berg]

On Thu, 2024-01-25 at 10:32 -0800, Jeff Johnson wrote:
> 
> OK, I have investigated this and based upon the investigation this can
> be removed (except for keeping the now obsolete uapi bits). This was
> done in preparation for supporting a new Android interface in the
> out-of-tree Android driver, but that interface was subsequently
> withdrawn by Google.
> 
> Johannes, do you want to handle this? Or should I?

Would be great if you could send a patch, thanks!

johannes