Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: fix use-after-free in chanctx code
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.
Details
- Affected product:
- CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS
- Affected packages:
- kernel @ 4.18.0 (+2 more)
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: fix use-after-free in chanctx code
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.