cfg80211: introduce scan IE limit attribute

This patch introduces a new attribute for a wiphy that tells
userspace how long the information elements added to a probe
request frame can be at most. It also updates the at76 to
advertise that it cannot support that, and, for now until I
can fix that, iwlwifi too.

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

1 files changed, 7 insertions, 0 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 1394115cde95..447fa1790b4e 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -181,6 +181,8 @@ static int nl80211_send_wiphy(struct sk_buff *msg, u32 pid, u32 seq, int flags,
         NLA_PUT_STRING(msg, NL80211_ATTR_WIPHY_NAME, wiphy_name(&dev->wiphy));
         NLA_PUT_U8(msg, NL80211_ATTR_MAX_NUM_SCAN_SSIDS,
                    dev->wiphy.max_scan_ssids);
+        NLA_PUT_U16(msg, NL80211_ATTR_MAX_SCAN_IE_LEN,
+                    dev->wiphy.max_scan_ie_len);
 
         nl_modes = nla_nest_start(msg, NL80211_ATTR_SUPPORTED_IFTYPES);
         if (!nl_modes)
@@ -2528,6 +2530,11 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
         else
                 ie_len = 0;
 
+        if (ie_len > wiphy->max_scan_ie_len) {
+                err = -EINVAL;
+                goto out;
+        }
+
         request = kzalloc(sizeof(*request)
                         + sizeof(*ssid) * n_ssids
                         + sizeof(channel) * n_channels