README
1sepolicy-analyze
2 A component-ized tool for performing various kinds of analysis on a
3 sepolicy file. The current kinds of analysis that are currently
4 supported include:
5
6 TYPE EQUIVALENCE (typecmp)
7 sepolicy-analyze out/target/product/<board>/root/sepolicy typecmp -e
8
9 Display all type pairs that are "equivalent", i.e. they are
10 identical with respect to allow rules, including indirect allow
11 rules via attributes and default-enabled conditional rules
12 (i.e. default boolean values yield a true conditional expression).
13
14 Equivalent types are candidates for being coalesced into a single
15 type. However, there may be legitimate reasons for them to remain
16 separate, for example: - the types may differ in a respect not
17 included in the current analysis, such as default-disabled
18 conditional rules, audit-related rules (auditallow or dontaudit),
19 default type transitions, or constraints (e.g. mls), or - the
20 current policy may be overly permissive with respect to one or the
21 other of the types and thus the correct action may be to tighten
22 access to one or the other rather than coalescing them together,
23 or - the domains that would in fact have different accesses to the
24 types may not yet be defined or may be unconfined in the policy
25 you are analyzing.
26
27 TYPE DIFFERENCE (typecmp)
28 sepolicy-analyze out/target/product/<board>/root/sepolicy typecmp -d
29
30 Display type pairs that differ and the first difference found
31 between the two types. This may be used in looking for similar
32 types that are not equivalent but may be candidates for coalescing.
33
34 DUPLICATE ALLOW RULES (dups)
35 sepolicy-analyze out/target/product/<board>/root/sepolicy dups
36
37 Displays duplicate allow rules, i.e. pairs of allow rules that
38 grant the same permissions where one allow rule is written
39 directly in terms of individual types and the other is written in
40 terms of attributes associated with those same types. The rule
41 with individual types is a candidate for removal. The rule with
42 individual types may be directly represented in the source policy
43 or may be a result of expansion of a type negation (e.g. domain
44 -foo -bar is expanded to individual allow rules by the policy
45 compiler). Domains with unconfineddomain will typically have such
46 duplicate rules as a natural side effect and can be ignored.
47
48 PERMISSIVE DOMAINS (permissive)
49 sepolicy-analyze out/target/product/<board>/root/sepolicy permissive
50
51 Displays domains in the policy that are permissive, i.e. avc
52 denials are logged but not enforced for these domains. While
53 permissive domains can be helpful during development, they
54 should not be present in a final -user build.
55
56 BOOLEANS (booleans)
57 sepolicy-analyze out/target/product/<board>/root/sepolicy booleans
58
59 Displays the boolean names in the policy (if any).
60 Policy booleans are forbidden in Android policy, so if there is any
61 output, the policy will fail CTS.
62
63 ATTRIBUTE (attribute)
64 sepolicy-analyze out/target/product/<board>/root/sepolicy attribute <name>
65
66 Displays the types associated with the specified attribute name.
67
68 sepolicy-analyze out/target/product/<board>/root/sepolicy attribute -r <name>
69
70 Displays the attributes associated with the specified type name.
71
72 sepolicy-analyze out/target/product/<board>/root/sepolicy attribute -l
73
74 Displays all attributes in the policy.
75
76 NEVERALLOW CHECKING (neverallow)
77 sepolicy-analyze out/target/product/<board>/root/sepolicy neverallow \
78 [-w] [-d] [-f neverallows.conf] | [-n "neverallow string"]
79
80 Check whether the sepolicy file violates any of the neverallow rules
81 from the neverallows.conf file or a given string, which contain neverallow
82 statements in the same format as the SELinux policy.conf file, i.e. after
83 m4 macro expansion of the rules from a .te file. You can use an entire
84 policy.conf file as the neverallows.conf file and sepolicy-analyze will
85 ignore everything except for the neverallows within it. You can also
86 specify this as a command-line string argument, which could be useful for
87 quickly checking an individual expanded rule or group of rules. If there are
88 no violations, sepolicy-analyze will exit successfully with no output.
89 Otherwise, sepolicy-analyze will report all violations and exit
90 with a non-zero exit status.
91
92 The -w or --warn option may be used to warn on any types, attributes,
93 classes, or permissions from a neverallow rule that could not be resolved
94 within the sepolicy file. This can be normal due to differences between
95 the policy from which the neverallow rules were taken and the policy
96 being checked. Such values are ignored for the purposes of neverallow
97 checking.
98
99 The -d or --debug option may be used to cause sepolicy-analyze to emit the
100 neverallow rules as it parses them. This is principally a debugging facility
101 for the parser but could also be used to extract neverallow rules from
102 a full policy.conf file and output them in a more easily parsed format.
103