From: Johannes Berg Date: Wed, 1 Jun 2022 07:19:36 +0000 (+0200) Subject: wifi: mac80211: fix use-after-free in chanctx code X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=b79110f2bf6022e60e590d2e094728a8eec3e79e;p=linux.git wifi: mac80211: fix use-after-free in chanctx code 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 Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/20220601091926.df419d91b165.I17a9b3894ff0b8323ce2afdb153b101124c821e5@changeid Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c index 76fc36a68750e..63e15f583e0a6 100644 --- a/net/mac80211/chan.c +++ b/net/mac80211/chan.c @@ -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); } /*