mac80211: twt: don't use potentially unaligned pointer

Since we're pointing into a frame, the pointer to the
twt_agrt->req_type struct member is potentially not
aligned properly. Open-code le16p_replace_bits() to
avoid passing an unaligned pointer.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: f5a4c24e689f ("mac80211: introduce individual TWT support in AP mode")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20210927115124.e1208694f37b.Ie3de9bcc5dde5a79e3ac81f3185beafe4d214e57@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/s1g.c b/net/mac80211/s1g.c
index 7e35ab5..4141bc8 100644 (file)
--- a/net/mac80211/s1g.c
+++ b/net/mac80211/s1g.c
@@ -104,9 +104,11 @@ ieee80211_s1g_rx_twt_setup(struct ieee80211_sub_if_data *sdata,
 
        /* broadcast TWT not supported yet */
        if (twt->control & IEEE80211_TWT_CONTROL_NEG_TYPE_BROADCAST) {
-               le16p_replace_bits(&twt_agrt->req_type,
-                                  TWT_SETUP_CMD_REJECT,
-                                  IEEE80211_TWT_REQTYPE_SETUP_CMD);
+               twt_agrt->req_type &=
+                       ~cpu_to_le16(IEEE80211_TWT_REQTYPE_SETUP_CMD);
+               twt_agrt->req_type |=
+                       le16_encode_bits(TWT_SETUP_CMD_REJECT,
+                                        IEEE80211_TWT_REQTYPE_SETUP_CMD);
                goto out;
        }