platform_system_sepolicy/zygote.te
Nick Kralevich f2c011892d zygote: allow replacing /proc/cpuinfo
Android's native bridge functionality allows an Android native
app written on one CPU architecture to run on a different architecture.
For example, Android ARM apps may run on an x86 CPU.

To support this, the native bridge functionality needs to replace
/proc/cpuinfo with the version from /system/lib/<ISA>/cpuinfo
using a bind mount. See commit ab0da5a9a6860046619629b8e6b83692d35dff86
in system/core.

This change:

1) Creates a new label proc_cpuinfo, and assigns /proc/cpuinfo
that label.
2) Grants read-only access to all SELinux domains, to avoid
breaking pre-existing apps.
3) Grants zygote mounton capabilities for that file, so zygote
can replace the file as necessary.

Addresses the following denial:

  avc: denied { mounton } for path="/proc/cpuinfo" dev="proc" ino=4026532012 scontext=u:r:zygote:s0 tcontext=u:object_r:proc:s0 tclass=file

Bug: 17671501

(cherry picked from commit 2de02877a3)

Change-Id: I2c2366bee4fe365288d14bca9778d23a43c368cb
2014-09-26 13:06:22 -07:00

58 lines
2.3 KiB
Text

# zygote
type zygote, domain;
type zygote_exec, exec_type, file_type;
init_daemon_domain(zygote)
typeattribute zygote mlstrustedsubject;
# Override DAC on files and switch uid/gid.
allow zygote self:capability { dac_override setgid setuid fowner chown };
# Drop capabilities from bounding set.
allow zygote self:capability setpcap;
# Switch SELinux context to app domains.
allow zygote self:process setcurrent;
allow zygote system_server:process dyntransition;
allow zygote appdomain:process dyntransition;
# Allow zygote to read app /proc/pid dirs (b/10455872)
allow zygote appdomain:dir { getattr search };
allow zygote appdomain:file { r_file_perms };
# Move children into the peer process group.
allow zygote system_server:process { getpgid setpgid };
allow zygote appdomain:process { getpgid setpgid };
# Read system data.
allow zygote system_data_file:dir r_dir_perms;
allow zygote system_data_file:file r_file_perms;
# Write to /data/dalvik-cache.
allow zygote dalvikcache_data_file:dir create_dir_perms;
allow zygote dalvikcache_data_file:file create_file_perms;
# Write to /data/resource-cache
allow zygote resourcecache_data_file:dir rw_dir_perms;
allow zygote resourcecache_data_file:file create_file_perms;
# For art.
allow zygote dalvikcache_data_file:file execute;
# Execute dexopt.
allow zygote system_file:file x_file_perms;
allow zygote dex2oat_exec:file rx_file_perms;
# Control cgroups.
allow zygote cgroup:dir create_dir_perms;
allow zygote self:capability sys_admin;
# Check validity of SELinux context before use.
selinux_check_context(zygote)
# Check SELinux permissions.
selinux_check_access(zygote)
# Read /seapp_contexts and /data/security/seapp_contexts
security_access_policy(zygote)
# Native bridge functionality requires that zygote replaces
# /proc/cpuinfo with /system/lib/<ISA>/cpuinfo using a bind mount
allow zygote proc_cpuinfo:file mounton;
# Setting up /storage/emulated.
allow zygote rootfs:dir mounton;
allow zygote sdcard_type:dir { write search setattr create add_name mounton };
dontaudit zygote self:capability fsetid;
allow zygote tmpfs:dir { write create add_name setattr mounton search };
allow zygote tmpfs:filesystem mount;
allow zygote labeledfs:filesystem remount;
# Handle --invoke-with command when launching Zygote with a wrapper command.
allow zygote zygote_exec:file rx_file_perms;