cfg80211: validate remain-on-channel time better

The remain-on-channel time validation shouldn't
depend on the value of HZ, as it does now with
the check against jiffies, since then you might
use a value that works on one system but not on
another. Fix it by checking against a minimum
that's fixed.

Also add validation of the wait duration for a
management frame TX since this also translates
into remain-on-channel internally.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 16 insertions, 7 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 5e29bd38e7d..7ae54b82291 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5545,18 +5545,18 @@ static int nl80211_remain_on_channel(struct sk_buff *skb,
 
         duration = nla_get_u32(info->attrs[NL80211_ATTR_DURATION]);
 
+        if (!rdev->ops->remain_on_channel ||
+            !(rdev->wiphy.flags & WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL))
+                return -EOPNOTSUPP;
+
         /*
-         * We should be on that channel for at least one jiffie,
-         * and more than 5 seconds seems excessive.
+         * We should be on that channel for at least a minimum amount of
+         * time (10ms) but no longer than the driver supports.
          */
-        if (!duration || !msecs_to_jiffies(duration) ||
+        if (duration < NL80211_MIN_REMAIN_ON_CHANNEL_TIME ||
             duration > rdev->wiphy.max_remain_on_channel_duration)
                 return -EINVAL;
 
-        if (!rdev->ops->remain_on_channel ||
-            !(rdev->wiphy.flags & WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL))
-                return -EOPNOTSUPP;
-
         if (info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE] &&
             !nl80211_valid_channel_type(info, &channel_type))
                 return -EINVAL;
@@ -5827,6 +5827,15 @@ static int nl80211_tx_mgmt(struct sk_buff *skb, struct genl_info *info)
                 if (!(rdev->wiphy.flags & WIPHY_FLAG_OFFCHAN_TX))
                         return -EINVAL;
                 wait = nla_get_u32(info->attrs[NL80211_ATTR_DURATION]);
+
+                /*
+                 * We should wait on the channel for at least a minimum amount
+                 * of time (10ms) but no longer than the driver supports.
+                 */
+                if (wait < NL80211_MIN_REMAIN_ON_CHANNEL_TIME ||
+                    wait > rdev->wiphy.max_remain_on_channel_duration)
+                        return -EINVAL;
+
         }
 
         if (info->attrs[NL80211_ATTR_WIPHY_CHANNEL_TYPE]) {