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  1. May 13, 2014
    • Nick Kralevich's avatar
      untrusted_app: neverallow debugfs · 4bdd13e4
      Nick Kralevich authored
      Too many leaky files in that directory. It's a security best practice
      to not mount this filesystem, however, we need it mounted for
      tracing support. Even though it's mounted, make sure the files aren't
      readable.
      
      Bug: 11635985
      Change-Id: I6f116c0a03a567a8107a8e07135ce025e51458dd
      4bdd13e4
  2. May 01, 2014
  3. Apr 04, 2014
    • Stephen Smalley's avatar
      Coalesce shared_app, media_app, release_app into untrusted_app. · 9ba844fe
      Stephen Smalley authored
      
      This change folds the shared_app, media_app, and release_app
      domains into untrusted_app, reducing the set of app domains down
      to just distinct domains for the fixed UID apps (e.g. system_app, bluetooth,
      nfc, radio), a single domain for apps signed by the platform key
      (platform_app), and a single domain for all other apps (untrusted_app).
      Thus, SELinux only distinguishes when already distinguished by a predefined
      Android ID (AID) or by the platform certificate (which get the signature-only
      Android permissions and thus may require special OS-level accesses).
      
      It is still possible to introduce specific app domains for specific
      apps by adding signer and package stanzas to mac_permissions.xml,
      but this can be done on an as-needed basis for specialized apps that
      require particular OS-level permissions outside the usual set.
      
      As there is now only a single platform app domains, get rid of the
      platformappdomain attribute and platform_app_domain() macro.  We used
      to add mlstrustedsubject to those domains but drop this since we are not
      using MLS in AOSP presently; we can revisit which domains need it if/when
      we use MLS.
      
      Since we are dropping the shared, media, and release seinfo entries from
      seapp_contexts, drop them from mac_permissions.xml as well.  However,
      we leave the keys.conf entries in case someone wants to add a signer
      entry in the future for specific apps signed by those keys to
      mac_permissions.xml.
      
      Change-Id: I877192cca07360c4a3c0ef475f016cc273e1d968
      Signed-off-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
      9ba844fe
  4. Mar 07, 2014
    • Stephen Smalley's avatar
      Clean up, unify, and deduplicate app domain rules. · b0db712b
      Stephen Smalley authored
      
      Coalesce a number of allow rules replicated among multiple
      app domains.
      
      Get rid of duplicated rules already covered by domain, appdomain,
      or platformappdomain rules.
      
      Split the platformappdomain rules to their own platformappdomain.te
      file, document them more fully, and note the inheritance in each
      of the relevant *_app.te files.
      
      Generalize isolated app unix_stream_socket rules to all app domains
      to resolve denials such as:
      
      avc:  denied  { read write } for  pid=11897 comm="Binder_2" path="socket:[203881]" dev="sockfs" ino=203881 scontext=u:r:release_app:s0 tcontext=u:r:untrusted_app:s0 tclass=unix_stream_socket
      
      avc:  denied  { getattr } for  pid=11990 comm=4173796E635461736B202334 path="socket:[203881]" dev="sockfs" ino=203881 scontext=u:r:release_app:s0 tcontext=u:r:untrusted_app:s0 tclass=unix_stream_socket
      
      avc:  denied  { getopt } for  pid=11990 comm=4173796E635461736B202334 scontext=u:r:release_app:s0 tcontext=u:r:untrusted_app:s0 tclass=unix_stream_socket
      
      avc:  denied  { read write } for  pid=6890 comm="Binder_10" path="socket:[205010]" dev="sockfs" ino=205010 scontext=u:r:release_app:s0 tcontext=u:r:media_app:s0 tclass=unix_stream_socket
      
      avc:  denied  { getattr } for  pid=11990 comm=4173796E635461736B202334 path="socket:[205010]" dev="sockfs" ino=205010 scontext=u:r:release_app:s0 tcontext=u:r:media_app:s0 tclass=unix_stream_socket
      
      avc:  denied  { getopt } for  pid=11990 comm=4173796E635461736B202334 scontext=u:r:release_app:s0 tcontext=u:r:media_app:s0 tclass=unix_stream_socket
      
      Change-Id: I770d7d51d498b15447219083739153265d951fe5
      Signed-off-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
      b0db712b
  5. Feb 24, 2014
  6. Feb 21, 2014
  7. Feb 11, 2014
  8. Jan 11, 2014
    • Nick Kralevich's avatar
      Support forcing permissive domains to unconfined. · 623975fa
      Nick Kralevich authored
      Permissive domains are only intended for development.
      When a device launches, we want to ensure that all
      permissive domains are in, at a minimum, unconfined+enforcing.
      
      Add FORCE_PERMISSIVE_TO_UNCONFINED to Android.mk. During
      development, this flag is false, and permissive domains
      are allowed. When SELinux new feature development has been
      frozen immediately before release, this flag will be flipped
      to true. Any previously permissive domains will move into
      unconfined+enforcing.
      
      This will ensure that all SELinux domains have at least a
      minimal level of protection.
      
      Unconditionally enable this flag for all user builds.
      
      Change-Id: I1632f0da0022c80170d8eb57c82499ac13fd7858
      623975fa
  9. Dec 11, 2013
    • Stephen Smalley's avatar
      Allow untrusted apps to execute binaries from their sandbox directories. · 65317124
      Stephen Smalley authored
      
      Various third party apps come with their own binaries that they write out to
      their sandbox directories and then execute, e.g.:
      audit(1386527439.462:190): avc:  denied  { execute_no_trans } for  pid=1550 comm="Thread-79" path="/data/data/com.cisco.anyconnect.vpn.android.avf/app_bin/busybox" dev="mmcblk0p23" ino=602891 scontext=u:r:untrusted_app:s0:c39,c256 tcontext=u:object_r:app_data_file:s0:c39,c256 tclass=file
      
      While this is not ideal from a security POV, it seems necessary to support for
      compatibility with Android today.
      
      Split out the execute-related permissions to a separate allow rule as it
      only makes sense for regular files (class file) not other kinds of files
      (e.g. fifos, sockets, symlinks), and use the rx_file_perms macro.
      
      Move the rule to untrusted_app only so that we do not permit system apps
      to execute files written by untrusted apps.
      
      Change-Id: Ic9bfe80e9b14f2c0be14295c70f23f09691ae66c
      Signed-off-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
      65317124
  10. Sep 27, 2013
    • Stephen Smalley's avatar
      Isolate untrusted app ptys from other domains. · 2dc4acf3
      Stephen Smalley authored
      
      Add a create_pty() macro that allows a domain to
      create and use its own ptys, isolated from the ptys
      of any other domain, and use that macro for untrusted_app.
      This permits the use of a pty by apps without opening up access
      to ptys created by any other domain on the system.
      
      Change-Id: I5d96ce4d1b26073d828e13eb71c48d1e14ce7d6b
      Signed-off-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
      2dc4acf3
  11. Sep 04, 2013
  12. Aug 17, 2013
  13. Aug 16, 2013
  14. Jul 16, 2013
  15. Jul 15, 2013
  16. Jul 14, 2013
    • Nick Kralevich's avatar
      untrusted_app.te / isolated_app.te / app.te first pass · 6634a108
      Nick Kralevich authored
      This is my first attempt at creating an enforcing SELinux domain for
      apps, untrusted_apps, and isolated_apps. Much of these rules are based on the
      contents of app.te as of commit 11153ef3
      with extensive modifications, some of which are included below.
      
      * Allow communication with netd/dnsproxyd, to allow netd to handle
        dns requests
      * Allow binder communications with the DNS server
      * Allow binder communications with surfaceflinger
      * Allow an app to bind to tcp/udp ports
      * Allow all domains to read files from the root partition, assuming
        the DAC allows access.
      
      In addition, I added a bunch of "neverallow" rules, to assert that
      certain capabilities are never added.
      
      This change has a high probability of breaking someone, somewhere.
      If it does, then I'm happy to fix the breakage, rollback this change,
      or put untrusted_app into permissive mode.
      
      Change-Id: I83f220135d20ab4f70fbd7be9401b5b1def1fe35
      6634a108
  17. Jul 13, 2013
    • Nick Kralevich's avatar
      Move *_app into their own file · 748fdef6
      Nick Kralevich authored
      app.te covers a lot of different apps types (platform_app, media_app,
      shared_app, release_app, isolated_app, and untrusted_app), all
      of which are going to have slightly different security policies.
      
      Separate the different domains from app.te. Over time, these
      files are likely to grow substantially, and mixing different domain types
      is a recipe for confusion and mistakes.
      
      No functional change.
      
      Change-Id: Ida4e77fadb510f5993eb2d32f2f7649227edff4f
      748fdef6
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