For match-all-type rules (e.g. "allow magisk * * *" used in Magisk),
we used to iterate and apply rules on all existing types. However, this
is actually unnecessary as all selinux types should have at least 1
attributes assigned to it (process types "domain", file context types
"file_type" etc.). This means in order to create rules that applies to
all types, we actually only need to create rules for all attributes.
This optimization SIGNIFICANTLY reduces the patched sepolicy that is
loaded into the kernel when running Magisk. For example on Pixel 4 XL
running Android R DP4, the sepolicy sizes are
patched (before) : 3455948
patched (after) : 843176
stock : 630229
The active sepolicy size actually impacts the performance of every single
operation in the operating system, because the larger the policies gets,
the longer it takes for the kernel to lookup and match rules.
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