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

[Johannes Berg]

On Wed, 2016-12-14 at 11:30 -0800, gree...@candelatech.com wrote:
> From: Ben Greear 
> 
> 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

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

[greearb]

From: Ben Greear 

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 
---

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, >rxrate);
-   sinfo->filled |= BIT(NL80211_STA_INFO_RX_BITRATE);
+   if (sta_set_rate_info_rx(sta, >rxrate) == 0)
+   sinfo->filled |= BIT(NL80211_STA_INFO_RX_BITRATE);
}
 
sinfo->filled |= BIT(NL80211_STA_INFO_TID_STATS);
-- 
2.4.11