wifi: mac80211: fix vif addr when switching from monitor to station

Since adding support for opting out of virtual monitor support, a zero vif
addr was used to indicate passive vs active monitor to the driver.
This would break the vif->addr when changing the netdev mac address before
switching the interface from monitor to sta mode.
Fix the regression by adding a separate flag to indicate whether vif->addr
is valid.

Reported-by: syzbot+9ea265d998de25ac6a46@syzkaller.appspotmail.com
Fixes: 9d40f7e32774 ("wifi: mac80211: add flag to opt out of virtual monitor support")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://patch.msgid.link/20241115115850.37449-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index adc2dd813a4a3fb72bfcc971592d9e5174a6521f..ab8dce1f2c2712d7131e99905785b69dfefec2e7 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1987,6 +1987,8 @@ enum ieee80211_neg_ttlm_res {
  * @neg_ttlm: negotiated TID to link mapping info.
  *     see &struct ieee80211_neg_ttlm.
  * @addr: address of this interface
+ * @addr_valid: indicates if the address is actively used. Set to false for
+ *     passive monitor interfaces, true in all other cases.
  * @p2p: indicates whether this AP or STA interface is a p2p
  *     interface, i.e. a GO or p2p-sta respectively
  * @netdev_features: tx netdev features supported by the hardware for this
@@ -2026,6 +2028,7 @@ struct ieee80211_vif {
        u16 valid_links, active_links, dormant_links, suspended_links;
        struct ieee80211_neg_ttlm neg_ttlm;
        u8 addr[ETH_ALEN] __aligned(2);
+       bool addr_valid;
        bool p2p;
 
        u8 cab_queue;

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index a36d295f127c77a7bcd1f4cf6261923c04fe57da..806dffa48ef9240559e44acc6cbdbf00216645a2 100644 (file)
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -278,13 +278,8 @@ static int _ieee80211_change_mac(struct ieee80211_sub_if_data *sdata,
        ret = eth_mac_addr(sdata->dev, sa);
 
        if (ret == 0) {
-               if (check_dup) {
-                       memcpy(sdata->vif.addr, sa->sa_data, ETH_ALEN);
-                       ether_addr_copy(sdata->vif.bss_conf.addr, sdata->vif.addr);
-               } else {
-                       memset(sdata->vif.addr, 0, ETH_ALEN);
-                       memset(sdata->vif.bss_conf.addr, 0, ETH_ALEN);
-               }
+               memcpy(sdata->vif.addr, sa->sa_data, ETH_ALEN);
+               ether_addr_copy(sdata->vif.bss_conf.addr, sdata->vif.addr);
        }
 
        /* Regardless of eth_mac_addr() return we still want to add the
@@ -1323,6 +1318,8 @@ int ieee80211_do_open(struct wireless_dev *wdev, bool coming_up)
                }
        }
 
+       sdata->vif.addr_valid = sdata->vif.type != NL80211_IFTYPE_MONITOR ||
+                               (sdata->u.mntr.flags & MONITOR_FLAG_ACTIVE);
        switch (sdata->vif.type) {
        case NL80211_IFTYPE_AP_VLAN:
                /* no need to tell driver, but set carrier and chanctx */