User controls @idx which to be used as index of hwsim_world_regdom_custom.
So, It can be exploited via Spectre-like attack. (speculative execution)
This kind of attack leaks address of hwsim_world_regdom_custom,
It leads an attacker to bypass security mechanism such as KASLR.
So sanitize @idx before using it to prevent attack.
I leveraged strategy [1] to find and exploit this gadget.
[1] https://github.com/jinb-park/linux-exploit/tree/master/exploit-remaining-spectre-gadget/
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
[johannes: unwrap URL]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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