[PATCH v2] mac80211: fix legacy and invalid rx-rate rpt

[PATCH v2] mac80211: fix legacy and invalid rx-rate rpt

[greearb]

From: Ben Greear <greearb@candelatech.com>

This fixes obtaining the rate info via sta_set_sinfo
when the rx rate is invalid (for instance, on IBSS
interface that has received no frames from one of its
peers).

This also fixes a more general issue with rinfo->flags
not being properly initialized for legacy rates.

Signed-off-by: Ben Greear <greearb@candelatech.com>
---

Patch is against 4.7

 net/mac80211/sta_info.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 01868f9..6d27813e 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -2057,6 +2057,7 @@ static void sta_stats_decode_rate(struct ieee80211_local *local, u16 rate,
 		u16 brate;
 		unsigned int shift;
 
+		rinfo->flags = 0;
 		sband = local->hw.wiphy->bands[(rate >> 4) & 0xf];
 		brate = sband->bitrates[rate & 0xf].bitrate;
 		if (rinfo->bw == RATE_INFO_BW_5)
@@ -2072,14 +2073,15 @@ static void sta_stats_decode_rate(struct ieee80211_local *local, u16 rate,
 		rinfo->flags |= RATE_INFO_FLAGS_SHORT_GI;
 }
 
-static void sta_set_rate_info_rx(struct sta_info *sta, struct rate_info *rinfo)
+static int sta_set_rate_info_rx(struct sta_info *sta, struct rate_info *rinfo)
 {
 	u16 rate = ACCESS_ONCE(sta_get_last_rx_stats(sta)->last_rate);
-
-	if (rate == STA_STATS_RATE_INVALID)
-		rinfo->flags = 0;
-	else
+	if (rate == STA_STATS_RATE_INVALID) {
+		return -EINVAL;
+	} else {
 		sta_stats_decode_rate(sta->local, rate, rinfo);
+		return 0;
+	}
 }
 
 static void sta_set_tidstats(struct sta_info *sta,
@@ -2284,8 +2286,8 @@ void sta_set_sinfo(struct sta_info *sta, struct station_info *sinfo)
 	}
 
 	if (!(sinfo->filled & BIT(NL80211_STA_INFO_RX_BITRATE))) {
-		sta_set_rate_info_rx(sta, &sinfo->rxrate);
-		sinfo->filled |= BIT(NL80211_STA_INFO_RX_BITRATE);
+		if (sta_set_rate_info_rx(sta, &sinfo->rxrate) == 0)
+			sinfo->filled |= BIT(NL80211_STA_INFO_RX_BITRATE);
 	}
 
 	sinfo->filled |= BIT(NL80211_STA_INFO_TID_STATS);
-- 
2.4.11

Re: [PATCH v2] mac80211: fix legacy and invalid rx-rate rpt

[Johannes Berg]

On Wed, 2016-12-14 at 11:30 -0800, greearb@candelatech.com wrote:
> From: Ben Greear <greearb@candelatech.com>
> 
> This fixes obtaining the rate info via sta_set_sinfo
> when the rx rate is invalid (for instance, on IBSS
> interface that has received no frames from one of its
> peers).
> 
> This also fixes a more general issue with rinfo->flags
> not being properly initialized for legacy rates.

I'd say this is a bug in the ethtool code - everything assumes (and
everything else makes sure) the whole sinfo struct is initialized to 0
before getting passed to this function.

> +static int sta_set_rate_info_rx(struct sta_info *sta, struct
> rate_info *rinfo)
>  {
>  	u16 rate = ACCESS_ONCE(sta_get_last_rx_stats(sta)-
> >last_rate);
> -
> -	if (rate == STA_STATS_RATE_INVALID)
> -		rinfo->flags = 0;
> -	else
> +	if (rate == STA_STATS_RATE_INVALID) {
> +		return -EINVAL;
> +	} else {
>  		sta_stats_decode_rate(sta->local, rate, rinfo);
> +		return 0;
> +	}

That's weird, I'll fix it.

Applied, with some fixupse.

johannes