mac80211: fix ibss scanning

Do not scan on no-IBSS and disabled channels in IBSS mode. Doing this
can trigger Microcode errors on iwlwifi and iwlegacy drivers.

Also rename ieee80211_request_internal_scan() function since it is only
used in IBSS mode and simplify calling it from ieee80211_sta_find_ibss().

This patch should address:
https://bugzilla.redhat.com/show_bug.cgi?id=883414
https://bugzilla.kernel.org/show_bug.cgi?id=49411

Reported-by: Jesse Kahtava <jesse_kahtava@f-m.fm>
Reported-by: Mikko Rapeli  <mikko.rapeli@iki.fi>
Cc: stable@vger.kernel.org
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

3 files changed, 31 insertions, 18 deletions

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 8881fc77fb13..6b7644e818d8 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -703,8 +703,8 @@ static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
         sdata_info(sdata,
                    "No active IBSS STAs - trying to scan for other IBSS networks with same SSID (merge)\n");
 
-        ieee80211_request_internal_scan(sdata,
-                        ifibss->ssid, ifibss->ssid_len, NULL);
+        ieee80211_request_ibss_scan(sdata, ifibss->ssid, ifibss->ssid_len,
+                                    NULL);
 }
 
 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
@@ -802,9 +802,8 @@ static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
                                         IEEE80211_SCAN_INTERVAL)) {
                 sdata_info(sdata, "Trigger new scan to find an IBSS to join\n");
 
-                ieee80211_request_internal_scan(sdata,
-                                ifibss->ssid, ifibss->ssid_len,
-                                ifibss->fixed_channel ? ifibss->channel : NULL);
+                ieee80211_request_ibss_scan(sdata, ifibss->ssid,
+                                            ifibss->ssid_len, chan);
         } else {
                 int interval = IEEE80211_SCAN_INTERVAL;
 
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 42d0d0267730..112bb6192399 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1329,9 +1329,9 @@ void ieee80211_mesh_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 
 /* scan/BSS handling */
 void ieee80211_scan_work(struct work_struct *work);
-int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
-                                    const u8 *ssid, u8 ssid_len,
-                                    struct ieee80211_channel *chan);
+int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
+                                const u8 *ssid, u8 ssid_len,
+                                struct ieee80211_channel *chan);
 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
                            struct cfg80211_scan_request *req);
 void ieee80211_scan_cancel(struct ieee80211_local *local);
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 8ed83dcc149f..de3532d18df1 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -832,9 +832,9 @@ int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
         return res;
 }
 
-int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
-                                    const u8 *ssid, u8 ssid_len,
-                                    struct ieee80211_channel *chan)
+int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata,
+                                const u8 *ssid, u8 ssid_len,
+                                struct ieee80211_channel *chan)
 {
         struct ieee80211_local *local = sdata->local;
         int ret = -EBUSY;
@@ -848,22 +848,36 @@ int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
 
         /* fill internal scan request */
         if (!chan) {
-                int i, nchan = 0;
+                int i, max_n;
+                int n_ch = 0;
 
                 for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                         if (!local->hw.wiphy->bands[band])
                                 continue;
-                        for (i = 0;
-                             i < local->hw.wiphy->bands[band]->n_channels;
-                             i++) {
-                                local->int_scan_req->channels[nchan] =
+
+                        max_n = local->hw.wiphy->bands[band]->n_channels;
+                        for (i = 0; i < max_n; i++) {
+                                struct ieee80211_channel *tmp_ch =
                                     &local->hw.wiphy->bands[band]->channels[i];
-                                nchan++;
+
+                                if (tmp_ch->flags & (IEEE80211_CHAN_NO_IBSS |
+                                                     IEEE80211_CHAN_DISABLED))
+                                        continue;
+
+                                local->int_scan_req->channels[n_ch] = tmp_ch;
+                                n_ch++;
                         }
                 }
 
-                local->int_scan_req->n_channels = nchan;
+                if (WARN_ON_ONCE(n_ch == 0))
+                        goto unlock;
+
+                local->int_scan_req->n_channels = n_ch;
         } else {
+                if (WARN_ON_ONCE(chan->flags & (IEEE80211_CHAN_NO_IBSS |
+                                                IEEE80211_CHAN_DISABLED)))
+                        goto unlock;
+
                 local->int_scan_req->channels[0] = chan;
                 local->int_scan_req->n_channels = 1;
         }