[PATCH] mwifiex: MAC randomization should not be persistent

[PATCH] mwifiex: MAC randomization should not be persistent

[Brian Norris]

nl80211 provides the NL80211_SCAN_FLAG_RANDOM_ADDR for every scan
request that should be randomized; the absence of such a flag means we
should not randomize. However, mwifiex was stashing the latest
randomization request and *always* using it for future scans, even those
that didn't set the flag.

Let's zero out the randomization info whenever we get a scan request
without NL80211_SCAN_FLAG_RANDOM_ADDR. I'd prefer to remove
priv->random_mac entirely (and plumb the randomization MAC properly
through the call sequence), but the spaghetti is a little difficult to
unravel here for me.

Fixes: c2a8f0ff9c6c ("mwifiex: support random MAC address for scanning")
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
Should this be tagged for -stable?

 drivers/net/wireless/marvell/mwifiex/cfg80211.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
index 1e3bd435a694..2d7e8a372bf1 100644
--- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c
+++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c
@@ -2528,9 +2528,11 @@ mwifiex_cfg80211_scan(struct wiphy *wiphy,
 			priv->random_mac[i] |= get_random_int() &
 					       ~(request->mac_addr_mask[i]);
 		}
+		ether_addr_copy(user_scan_cfg->random_mac, priv->random_mac);
+	} else {
+		eth_zero_addr(priv->random_mac);
 	}
 
-	ether_addr_copy(user_scan_cfg->random_mac, priv->random_mac);
 	user_scan_cfg->num_ssids = request->n_ssids;
 	user_scan_cfg->ssid_list = request->ssids;
 
-- 
2.12.2.715.g7642488e1d-goog

Re: [PATCH] mwifiex: MAC randomization should not be persistent

[Kalle Valo]

Brian Norris <briannorris@chromium.org> writes:

> nl80211 provides the NL80211_SCAN_FLAG_RANDOM_ADDR for every scan
> request that should be randomized; the absence of such a flag means we
> should not randomize. However, mwifiex was stashing the latest
> randomization request and *always* using it for future scans, even those
> that didn't set the flag.
>
> Let's zero out the randomization info whenever we get a scan request
> without NL80211_SCAN_FLAG_RANDOM_ADDR. I'd prefer to remove
> priv->random_mac entirely (and plumb the randomization MAC properly
> through the call sequence), but the spaghetti is a little difficult to
> unravel here for me.
>
> Fixes: c2a8f0ff9c6c ("mwifiex: support random MAC address for scanning")

So the first release with this was v4.9.

> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---
> Should this be tagged for -stable?

IMHO yes.

-- 
Kalle Valo

Re: [PATCH] mwifiex: MAC randomization should not be persistent

[Brian Norris]

On Thu, Apr 06, 2017 at 07:02:15AM +0300, Kalle Valo wrote:
> Brian Norris <briannorris@chromium.org> writes:
> 
> > nl80211 provides the NL80211_SCAN_FLAG_RANDOM_ADDR for every scan
> > request that should be randomized; the absence of such a flag means we
> > should not randomize. However, mwifiex was stashing the latest
> > randomization request and *always* using it for future scans, even those
> > that didn't set the flag.
> >
> > Let's zero out the randomization info whenever we get a scan request
> > without NL80211_SCAN_FLAG_RANDOM_ADDR. I'd prefer to remove
> > priv->random_mac entirely (and plumb the randomization MAC properly
> > through the call sequence), but the spaghetti is a little difficult to
> > unravel here for me.
> >
> > Fixes: c2a8f0ff9c6c ("mwifiex: support random MAC address for scanning")
> 
> So the first release with this was v4.9.
> 
> > Signed-off-by: Brian Norris <briannorris@chromium.org>
> > ---
> > Should this be tagged for -stable?
> 
> IMHO yes.

Sounds fine to me. I suppose you'll do this when applying? Or I can
resend...

Brian

Re: [PATCH] mwifiex: MAC randomization should not be persistent

[Kalle Valo]

Brian Norris <briannorris@chromium.org> writes:

> On Thu, Apr 06, 2017 at 07:02:15AM +0300, Kalle Valo wrote:
>> Brian Norris <briannorris@chromium.org> writes:
>> 
>> > nl80211 provides the NL80211_SCAN_FLAG_RANDOM_ADDR for every scan
>> > request that should be randomized; the absence of such a flag means we
>> > should not randomize. However, mwifiex was stashing the latest
>> > randomization request and *always* using it for future scans, even those
>> > that didn't set the flag.
>> >
>> > Let's zero out the randomization info whenever we get a scan request
>> > without NL80211_SCAN_FLAG_RANDOM_ADDR. I'd prefer to remove
>> > priv->random_mac entirely (and plumb the randomization MAC properly
>> > through the call sequence), but the spaghetti is a little difficult to
>> > unravel here for me.
>> >
>> > Fixes: c2a8f0ff9c6c ("mwifiex: support random MAC address for scanning")
>> 
>> So the first release with this was v4.9.
>> 
>> > Signed-off-by: Brian Norris <briannorris@chromium.org>
>> > ---
>> > Should this be tagged for -stable?
>> 
>> IMHO yes.
>
> Sounds fine to me. I suppose you'll do this when applying? Or I can
> resend...

I can add this:

Cc: <stable@vger.kernel.org> # 4.9+

-- 
Kalle Valo

Re: mwifiex: MAC randomization should not be persistent

[Kalle Valo]

Brian Norris <briannorris@chromium.org> wrote:
> nl80211 provides the NL80211_SCAN_FLAG_RANDOM_ADDR for every scan
> request that should be randomized; the absence of such a flag means we
> should not randomize. However, mwifiex was stashing the latest
> randomization request and *always* using it for future scans, even those
> that didn't set the flag.
> 
> Let's zero out the randomization info whenever we get a scan request
> without NL80211_SCAN_FLAG_RANDOM_ADDR. I'd prefer to remove
> priv->random_mac entirely (and plumb the randomization MAC properly
> through the call sequence), but the spaghetti is a little difficult to
> unravel here for me.
> 
> Fixes: c2a8f0ff9c6c ("mwifiex: support random MAC address for scanning")
> Cc: <stable@vger.kernel.org> # 4.9+
> Signed-off-by: Brian Norris <briannorris@chromium.org>

Patch applied to wireless-drivers-next.git, thanks.

7e2f18f06408 mwifiex: MAC randomization should not be persistent

-- 
https://patchwork.kernel.org/patch/9665813/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches