Either I missed some discussion or there is some misinformation here.

CAP_SETPCAP is dangerous when CONFIG_SECURITY_FILE_CAPABILITIES=n
because then it allows a task to grant capabilities to other tasks.  So
when CONFIG_SECURITY_FILE_CAPABILITIES=n, then CAP_SETPCAP is taken away
at boot.  Note however that init can reinsert it into the bounding set
using /proc/sys/kernel/cap-bound.  Only init can do it.

CAP_SETPCAP is safe when CONFIG_SECURITY_FILE_CAPABILITIES=y, because
all it then allows is adding capabilities to the inheritable set (if
they are in the bounding set).  From there, it (or a child) needs to
execute a file with the same bits in the file inheritable set in order
to be able to get them into the permitted set.  In other words, it's a
way for login to grant capabilities to login sessions.

I'd like to see CONFIG_SECURITY_FILE_CAPABILITIES enabled so I can start
using them on my ubuntu laptop, like I used to on my old laptop.

-- 
ubuntu kernel removes CAP_SETPCAP
https://bugs.launchpad.net/bugs/95089
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