TheArchive/Magisk
1
0
Fork 0
mirror of https://github.com/topjohnwu/Magisk.git synced 2025-10-25 04:40:18 +00:00
Code Issues Packages Projects Releases Wiki Activity

Optimize match-all-type rules

Browse Source 
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.
This commit is contained in:
topjohnwu
2020-05-24 05:41:19 -07:00
parent 951273f8ef
commit cd6eca1dc2
2 changed files with 59 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
native/jni/magiskpolicy/sepolicy.hpp
View File

@@ -8,11 +8,11 @@ struct sepol_impl : public sepolicy {
int set_attr(const char *attr_name, int type_val);
void check_avtab_node(avtab_ptr_t node);
avtab_ptr_t get_avtab_node(avtab_key_t *key, avtab_extended_perms_t *xperms);
bool add_rule(const char *s, const char *t, const char *c, const char *p, int effect, bool n);
void add_rule(type_datum_t *src, type_datum_t *tgt, class_datum_t *cls, perm_datum_t *perm, int effect, bool n);
bool add_rule(const char *s, const char *t, const char *c, const char *p, int effect, bool invert);
void add_rule(type_datum_t *src, type_datum_t *tgt, class_datum_t *cls, perm_datum_t *perm, int effect, bool invert);
void add_xperm_rule(type_datum_t *src, type_datum_t *tgt,
class_datum_t *cls, uint16_t low, uint16_t high, int effect, bool n);
bool add_xperm_rule(const char *s, const char *t, const char *c, const char *range, int effect, bool n);
class_datum_t *cls, uint16_t low, uint16_t high, int effect, bool invert);
bool add_xperm_rule(const char *s, const char *t, const char *c, const char *range, int effect, bool invert);
bool add_type_rule(const char *s, const char *t, const char *c, const char *d, int effect);
bool add_filename_trans(const char *s, const char *t, const char *c, const char *d, const char *o);
bool add_genfscon(const char *fs_name, const char *path, const char *context);