mac80211: Fix setting TX power on monitor interfaces

Instead of calling ieee80211_recalc_txpower on monitor interfaces
directly, call it using the virtual monitor interface, if one exists.

In case of a single monitor interface given, reject setting TX power,
if no virtual monitor interface exists.

That being checked, don't warn in ieee80211_bss_info_change_notify,
after setting TX power on a monitor interface.

Fixes warning:
------------[ cut here ]------------
 WARNING: CPU: 0 PID: 2193 at net/mac80211/driver-ops.h:167
 ieee80211_bss_info_change_notify+0x111/0x190 Modules linked in: uvcvideo
 videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core
rndis_host cdc_ether usbnet mii tp_smapi(O) thinkpad_ec(O) ohci_hcd vboxpci(O)
 vboxnetadp(O) vboxnetflt(O) v boxdrv(O) x86_pkg_temp_thermal kvm_intel kvm
 irqbypass iwldvm iwlwifi ehci_pci ehci_hcd tpm_tis tpm_tis_core tpm CPU: 0
 PID: 2193 Comm: iw Tainted: G           O    4.12.12-gentoo #2 task:
 ffff880186fd5cc0 task.stack: ffffc90001b54000 RIP:
 0010:ieee80211_bss_info_change_notify+0x111/0x190 RSP: 0018:ffffc90001b57a10
 EFLAGS: 00010246 RAX: 0000000000000006 RBX: ffff8801052ce840 RCX:
 0000000000000064 RDX: 00000000fffffffc RSI: 0000000000040000 RDI:
 ffff8801052ce840 RBP: ffffc90001b57a38 R08: 0000000000000062 R09:
 0000000000000000 R10: ffff8802144b5000 R11: ffff880049dc4614 R12:
 0000000000040000 R13: 0000000000000064 R14: ffff8802105f0760 R15:
 ffffc90001b57b48 FS:  00007f92644b4580(0000) GS:ffff88021e200000(0000)
 knlGS:0000000000000000 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f9263c109f0 CR3: 00000001df850000 CR4: 00000000000406f0
 Call Trace:
  ieee80211_recalc_txpower+0x33/0x40
  ieee80211_set_tx_power+0x40/0x180
  nl80211_set_wiphy+0x32e/0x950

Reported-by: Peter Große <pegro@friiks.de>
Signed-off-by: Peter Große <pegro@friiks.de>

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 27 insertions, 1 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index b77ee342b5f8..46028e12e216 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2376,10 +2376,17 @@ static int ieee80211_set_tx_power(struct wiphy *wiphy,
         struct ieee80211_sub_if_data *sdata;
         enum nl80211_tx_power_setting txp_type = type;
         bool update_txp_type = false;
+        bool has_monitor = false;
 
         if (wdev) {
                 sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
 
+                if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
+                        sdata = rtnl_dereference(local->monitor_sdata);
+                        if (!sdata)
+                                return -EOPNOTSUPP;
+                }
+
                 switch (type) {
                 case NL80211_TX_POWER_AUTOMATIC:
                         sdata->user_power_level = IEEE80211_UNSET_POWER_LEVEL;
@@ -2418,15 +2425,34 @@ static int ieee80211_set_tx_power(struct wiphy *wiphy,
 
         mutex_lock(&local->iflist_mtx);
         list_for_each_entry(sdata, &local->interfaces, list) {
+                if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
+                        has_monitor = true;
+                        continue;
+                }
                 sdata->user_power_level = local->user_power_level;
                 if (txp_type != sdata->vif.bss_conf.txpower_type)
                         update_txp_type = true;
                 sdata->vif.bss_conf.txpower_type = txp_type;
         }
-        list_for_each_entry(sdata, &local->interfaces, list)
+        list_for_each_entry(sdata, &local->interfaces, list) {
+                if (sdata->vif.type == NL80211_IFTYPE_MONITOR)
+                        continue;
                 ieee80211_recalc_txpower(sdata, update_txp_type);
+        }
         mutex_unlock(&local->iflist_mtx);
 
+        if (has_monitor) {
+                sdata = rtnl_dereference(local->monitor_sdata);
+                if (sdata) {
+                        sdata->user_power_level = local->user_power_level;
+                        if (txp_type != sdata->vif.bss_conf.txpower_type)
+                                update_txp_type = true;
+                        sdata->vif.bss_conf.txpower_type = txp_type;
+
+                        ieee80211_recalc_txpower(sdata, update_txp_type);
+                }
+        }
+
         return 0;
 }