[PATCH] mac80211: sanity check CW_min/CW_max towards driver

[Johannes Berg]

From: Johannes Berg <johannes.berg-***@public.gmane.org>

There's no reason to ever set invalid CW_min/CW_max to the
drivers, we should catch it in higher layers. However, the
consequences of setting it wrong can be quite severe, so
double-check at a low level and error out for invalid data.

Change-Id: Ibf01670252676f2b6238308e0e2ef74475fbc1b0
Signed-off-by: Johannes Berg <johannes.berg-***@public.gmane.org>
Reviewed-on: https://gerrit.rds.intel.com/45309
Tested-by: IWL Jenkins
---
net/mac80211/driver-ops.h | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 1bbb0790264f..3df28e0fa045 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -631,6 +631,12 @@ static inline int drv_conf_tx(struct ieee80211_local *local,
if (!check_sdata_in_driver(sdata))
return -EIO;

+ if (WARN_ONCE(params->cw_min == 0 ||
+ params->cw_min > params->cw_max,
+ "%s: invalid CW_min/CW_max: %d/%d\n",
+ sdata->name, params->cw_min, params->cw_max))
+ return -EINVAL;
+
trace_drv_conf_tx(local, sdata, ac, params);
if (local->ops->conf_tx)
ret = local->ops->conf_tx(&local->hw, &sdata->vif,