wifi: libertas_tf: fix use-after-free in lbtf_free_adapter()

lbtf_free_adapter() calls timer_delete(&priv->command_timer), which does
not wait for a running command_timer_fn() callback. lbtf_free_adapter()
runs on the teardown path right before ieee80211_free_hw() frees priv,
both in lbtf_remove_card() and in the probe error path. command_timer is
armed by mod_timer() in lbtf_cmd() whenever a firmware command is sent.
command_timer_fn() dereferences priv. If a command times out as the
device is removed, command_timer_fn() runs concurrently with teardown and
dereferences priv after it has been freed.

This is the same use-after-free that commit 03cc8f90d053 ("wifi: libertas:
fix use-after-free in lbs_free_adapter()") fixed in the sibling libertas
driver. The libertas_tf variant has the identical pattern and was left
unchanged. Use timer_delete_sync() so any in-flight callback completes
before priv is freed.

Fixes: 06b16ae53192 ("libertas_tf: main.c, data paths and mac80211 handlers")
Cc: stable@vger.kernel.org
Signed-off-by: Maoyi Xie <maoyixie.tju@gmail.com>
Link: https://patch.msgid.link/178211481807.2212567.8773346114561900100@maoyixie.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/marvell/libertas_tf/main.c b/drivers/net/wireless/marvell/libertas_tf/main.c
index fb20fe31cd363bf250b1bd1124bd646e6a5f4d7a..42be6fa22f9c6aa973c2f2e2711fc84d1aab6b3c 100644 (file)
--- a/drivers/net/wireless/marvell/libertas_tf/main.c
+++ b/drivers/net/wireless/marvell/libertas_tf/main.c
@@ -174,7 +174,7 @@ static void lbtf_free_adapter(struct lbtf_private *priv)
 {
        lbtf_deb_enter(LBTF_DEB_MAIN);
        lbtf_free_cmd_buffer(priv);
-       timer_delete(&priv->command_timer);
+       timer_delete_sync(&priv->command_timer);
        lbtf_deb_leave(LBTF_DEB_MAIN);
 }