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wifi: mac80211: fix use-after-free in chanctx code

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commit 2965c4cdf7ad9ce0796fac5e57debb9519ea721e upstream.

In ieee80211_vif_use_reserved_context(), when we have an
old context and the new context's replace_state is set to
IEEE80211_CHANCTX_REPLACE_NONE, we free the old context
in ieee80211_vif_use_reserved_reassign(). Therefore, we
cannot check the old_ctx anymore, so we should set it to
NULL after this point.

However, since the new_ctx replace state is clearly not
IEEE80211_CHANCTX_REPLACES_OTHER, we're not going to do
anything else in this function and can just return to
avoid accessing the freed old_ctx.

Cc: stable@vger.kernel.org
Fixes: 5bcae31d9cb1 ("mac80211: implement multi-vif in-place reservations")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220601091926.df419d91b165.I17a9b3894ff0b8323ce2afdb153b101124c821e5@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johannes Berg 2022-06-01 09:19:36 +02:00 committed by Greg Kroah-Hartman
parent 4a6ca6f8a3
commit b79110f2bf
1 changed files with 2 additions and 5 deletions
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7
net/mac80211/chan.c
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@ -1746,12 +1746,9 @@ int ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata)
if (new_ctx->replace_state == IEEE80211_CHANCTX_REPLACE_NONE) {
if (old_ctx)
err = ieee80211_vif_use_reserved_reassign(sdata);
else
err = ieee80211_vif_use_reserved_assign(sdata);
return ieee80211_vif_use_reserved_reassign(sdata);
if (err)
return err;
return ieee80211_vif_use_reserved_assign(sdata);
}
/*