Description: Use-after-free in Android xt_qtaguid
References:
 https://source.android.com/security/bulletin/2021-03-01
 https://android.googlesource.com/kernel/common/+/2bd81ced0685922df12f4be3338ea632805624e9
Notes:
 carnil> Bulletin refers to upstream kernel but unconfirmed. According
 carnil> to Moritz this is just in Android specific xt_qtaguid code and
 carnil> so actually not "upstream kernel".
 bwh> The bulletin links to source commits which are definitely not
 bwh> touching upstream code.
Bugs:
upstream: N/A "Vulnerable code not present"
5.10-upstream-stable: N/A "Vulnerable code not present"
4.19-upstream-stable: N/A "Vulnerable code not present"
4.9-upstream-stable: N/A "Vulnerable code not present"
sid: N/A "Vulnerable code not present"
4.19-buster-security: N/A "Vulnerable code not present"
4.9-stretch-security: N/A "Vulnerable code not present"