nl80211: return error for invalid center_freq in 40 MHz

When NL80211_ATTR_WIPHY_CHANNEL_TYPE is given, nl80211 would parse the
channel definition the old way, discarding NL80211_ATTR_CENTER_FREQ1,
NL80211_ATTR_CENTER_FREQ2 etc. However, it is possible that user space
added both NL80211_ATTR_WIPHY_CHANNEL_TYPE and NL80211_ATTR_CENTER_FREQ1
or NL80211_ATTR_CENTER_FREQ2 assuming that all settings would be honored.

In such a case, validate that NL80211_ATTR_CENTER_FREQ1 and
NL80211_ATTR_CENTER_FREQ2 values match the channel configuration,
as otherwise user space would assume that the desired configuration was
applied.

For example, when trying to start ap with
NL80211_ATTR_WIPHY_CHANNEL_TYPE = NL80211_CHAN_HT40MINUS,
NL80211_ATTR_WIPHY_FREQ = 5180 and NL80211_ATTR_CENTER_FREQ1 = 5250
without this fix, the ap will start on channel 36 (center_freq1 will be
corrected to 5180).  With this fix, we will throw an error instead.

Signed-off-by: Tova Mussai <tova.mussai@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 0df8023f480bb69feb4cc2d3e0df6ea95f384e1a..66e97136ab44fb836814a96e50bbb8e7f151eb05 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2122,6 +2122,15 @@ static int nl80211_parse_chandef(struct cfg80211_registered_device *rdev,
                case NL80211_CHAN_HT40MINUS:
                        cfg80211_chandef_create(chandef, chandef->chan,
                                                chantype);
+                       /* user input for center_freq is incorrect */
+                       if (info->attrs[NL80211_ATTR_CENTER_FREQ1] &&
+                           chandef->center_freq1 != nla_get_u32(
+                                       info->attrs[NL80211_ATTR_CENTER_FREQ1]))
+                               return -EINVAL;
+                       /* center_freq2 must be zero */
+                       if (info->attrs[NL80211_ATTR_CENTER_FREQ2] &&
+                           nla_get_u32(info->attrs[NL80211_ATTR_CENTER_FREQ2]))
+                               return -EINVAL;
                        break;
                default:
                        return -EINVAL;