With the sepolicy-analyze neverallow checking, attribute
expansion is performed against the device policy and therefore
we do not want our neverallow rules to exempt domains from
consideration based on an attribute (e.g. -unconfineddomain).
Otherwise, device policy could pass the neverallow check just
by adding more domains to unconfineddomain. We could of course
add a CTS test to check the list of unconfineddomains against
a whitelist, but it seems desirable regardless to narrow these
neverallow rules to only the specific domains required.
There are three such neverallow rules in current policy: one
on creating unlabeled files, one on accessing /dev/hw_random, and
one on accessing a character device without a specific type. The
only domain in unconfineddomain that appears to have a legitimate
need for any of these permissions is the init domain. Replace
-unconfineddomain with -init in these neverallow rules, exclude these
permissions from unconfineddomain, and add these permissions to init if
not already explicitly allowed. auditallow accesses by init to files
and character devices left in the generic device type so we can monitor
what is being left there, although it is not necessarily a problem unless
the file or device should be accessible to others.
Change-Id: If6ee1b1a337c834971c6eb21dada5810608babcf
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Prune down unconfined so it doesn't allow process access
to all other domains. Use domain_trans() for transitions to
seclabeled domains.
Change-Id: I8e88a49e588b6b911e1f7172279455838a06091d
Introduce a net_radio_prop type for net. properties that can be
set by radio or system.
Introduce a system_radio_prop type for sys. properties that can be
set by radio or system.
Introduce a dhcp_prop type for properties that can be set by dhcp or system.
Drop the rild_prop vs radio_prop distinction; this was an early
experiment to see if we could separate properties settable by rild
versus other radio UID processes but it did not pan out.
Remove the ability to set properties from unconfineddomain.
Allow init to set any property. Allow recovery to set ctl_default_prop
to restart adbd.
Change-Id: I5ccafcb31ec4004dfefcec8718907f6b6f3e0dfd
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Don't allow unconfined domains to access the internet. Restrict
internet functionality to domains which explicitly declare their
use. Removing internet access from unconfined domains helps
protect daemons from network level attacks.
In unconfined.te, expand out socket_class_set, and explicitly remove
tcp_socket, udp_socket, rawip_socket, packet_socket, and
appletalk_socket. Remove name_bind, node_bind and name_connect rules,
since they only apply to internet accessible rules.
Add limited udp support to init.te. This is needed to bring up
the loopback interface at boot.
Change-Id: If756f3fed857f11e63a6c3a1a13263c57fdf930a
execmod is checked on attempts to make executable a file mapping
that has been modified. Typically this indicates a text relocation
attempt. As we do not ever allow this for any confined domain to
system_file or exec_type, we should not need it for unconfineddomain
either.
Change-Id: I8fdc858f836ae0d2aa56da2abd7797fba9c258b1
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Require sdcard_type access to be explicitly allowed to
each domain. This is to both protect services from
being killed by unsafe ejection and to protect SDcard
data from access by rogue daemons.
Change-Id: If3bdd50fd2be50bd98d755b2f252e0ae455b82c4
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Require app_data_file access to be explicitly allowed to
each domain. We especially do not want to allow
app_data_file:lnk_file read to any privileged domain.
But removing app_data_file access in general can be useful
in protecting app data from rogue daemons.
Change-Id: I46240562bce76579e108495ab15833e143841ad8
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Remove write access to rootfs files from unconfineddomain and
prevent adding it back via neverallow. This is only applied to
regular files, as we are primarily concerned with preventing
writing to a file that can be exec'd and because creation of
directories or symlinks in the rootfs may be required for mount
point directories.
Change-Id: If2c96da03f5dd6f56de97131f6ba9eceea328721
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
execute_no_trans controls whether a domain can execve a program
without switching to another domain. Exclude this permission from
unconfineddomain, add it back to init, init_shell, and recovery for
files in / and /system, and to kernel for files in / (to permit
execution of init prior to setcon). Prohibit it otherwise for the
kernel domain via neverallow. This ensures that if a kernel task
attempts to execute a kernel usermodehelper for which no domain transition
is defined, the exec will fail.
Change-Id: Ie7b2349923672dd4f5faf7c068a6e5994fd0e4e3
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Also rewrite to use positive permission sets, macros, and
eliminate duplication.
Change-Id: I4dc340784f770e569160025a5db2dc3da90d2629
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Prior to this change, the init and recovery domains were
allowed unrestricted use of context= mount options to force
all files within a given filesystem to be treated as having a
security context specified at mount time. The context= mount
option can be used in device-specific fstab.<board> files
to assign a context to filesystems that do not support labeling
such as vfat where the default label of sdcard_external is not
appropriate (e.g. /firmware on hammerhead).
Restrict the use of context= mount options to types marked with the
contextmount_type attribute, and then remove write access from
such types from unconfineddomain and prohibit write access to such
types via neverallow. This ensures that the no write to /system
restriction cannot be bypassed via context= mount.
Change-Id: I4e773fadc9e11328d13a0acec164124ad6e840c1
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Domains which want to access /data/local/tmp must do so by
creating their own SELinux domain.
Bug: 15164984
Change-Id: I0061129c64e659c552cf6565058b0786fba59ae0
Rewrote the process policy in external/sepolicy/unconfined.te
from a blacklist to a whitelist to be more easily understood.
There were previously 11 disallowed permissions and now there are
19 allowed permissions.
Change-Id: Ida4dc881c5fedc56980324774f40e09a9b8a830a
Remove /data/security and setprop selinux.reload_policy access
from unconfineddomain, and only add back what is needed to
init (system_server already gets the required allow rules via
the selinux_manage_policy macro).
init (via init.rc post-fs-data) originally creates /data/security
and may later restorecon it. init also sets the property (also from
init.rc post-fs-data) to trigger a reload once /data is mounted.
The system_server (SELinuxPolicyInstallReceiver in particular) creates
subdirectories under /data/security for updates, writes files to these
subdirectories, creates the /data/security/current symlink to the update
directory, and sets the property to trigger a reload when an update bundle
is received.
Add neverallow rules to ensure that we do not allow undesired access
to security_file or security_prop.
This is only truly meaningful if the support for /data/security policies
is restored, but is harmless otherwise.
Also drop the persist.mmac property_contexts entry; it was never used in
AOSP, only in our tree (for middleware MAC) and is obsolete.
Change-Id: I5ad5e3b6fc7abaafd314d31723f37b708d8fcf89
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Don't allow writes to /system from unconfined domains.
/system is always mounted read-only, and no process should
ever need to write there.
Allow recovery to write to /system. This is needed to apply OTA
images.
Change-Id: I11aa8bd0c3b7f53ebe83806a0547ab8d5f25f3c9
/data/property is only accessible by root and is used by the init
property service for storing persistent property values. Create
a separate type for it and only allow init to write to the directory
and files within it. Ensure that we do not allow access to other domains
in future changes or device-specific policy via a neverallow rule.
Change-Id: Iff556b9606c5651c0f1bba902e30b59bdd6f063a
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
As suggested in https://android-review.googlesource.com/95966 , remove
various syslog_* from unconfined. SELinux domains which want to use
syslog_* can declare it themselves.
Change-Id: I7a8335850d1b8d3463491b4ef8c657f57384cfa4
Change I6a2fb1279318625a80f3ea8e3f0932bdbe6df676 removed
these permissions from domain.te and added them to specific domains
as required. Remove the permissions from unconfineddomain as well
so that they are only allowed where explicitly allowed. The earlier
change already added the necessary permissions to init, kernel,
and recovery so we do not need to add them here.
Change-Id: Ifeb5438532a7525e64328e1c54b436e9b6f7fd3b
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Only keystore itself should be reading / writing it's files.
Remove keystore file access from other SELinux domains, including
unconfined. Add neverallow rules to protect against regressions.
Allow init limited access to recurse into keystore's directory.
Change-Id: I0bb5de7804f4314997c16fac18507933014bcadf
Require them to be explicitly granted by specific allow rules.
audit_write is required to write an audit message from userspace.
audit_control is required to configure the audit subsystem.
Change-Id: I5aa4e3228f9b0bde3570689fe7a0d68e56861a17
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
We already have neverallow rules for all domains about
loading policy, setting enforcing mode, and setting
checkreqprot, so we can drop redundant ones from netd and appdomain.
Add neverallow rules to domain.te for setbool and setsecparam
and exclude them from unconfined to allow fully eliminating
separate neverallow rules on the :security class from anything
other than domain.te.
Change-Id: I0122e23ccb2b243f4c5376893e0c894f01f548fc
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Only allow to domains as required and amend the existing
neverallow on block_device:blk_file to replace the
exemption for unconfineddomain with an explicit whitelist.
The neverallow does not check other device types as specific
ones may need to be writable by device-specific domains.
Change-Id: I0f2f1f565e886ae110a719a08aa3a1e7e9f23e8c
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Remove sys_ptrace and add a neverallow for it.
Remove sys_rawio and mknod, explicitly allow to kernel, init, and recovery,
and add a neverallow for them.
Remove sys_module. It can be added back where appropriate in device
policy if using a modular kernel. No neverallow since it is device
specific.
Change-Id: I1a7971db8d247fd53a8f9392de9e46250e91f89b
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Only allow to specific domains as required, and add a neverallow
to prevent allowing it to other domains not explicitly whitelisted.
sdcard_type is exempted from the neverallow since more domains
require the ability to mount it, including device-specific domains.
Change-Id: Ia6476d1c877f5ead250749fb12bff863be5e9f27
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Linux defines two capabilities for Mandatory Access Control (MAC)
security modules, CAP_MAC_OVERRIDE (override MAC access restrictions)
and CAP_MAC_ADMIN (allow MAC configuration or state changes).
SELinux predates these capabilities and did not originally use them,
but later made use of CAP_MAC_ADMIN as a way to control the ability
to set security context values unknown to the currently loaded
SELinux policy on files. That facility is used in Linux for e.g.
livecd creation where a file security context that is being set
on a generated filesystem is not known to the build host policy.
Internally, files with such labels are treated as having the unlabeled
security context for permission checking purposes until/unless the
context is later defined through a policy reload.
CAP_MAC_OVERRIDE is never checked by SELinux, so it never needs
to be allowed. CAP_MAC_ADMIN is only checked if setting an
unknown security context value; the only legitimate use I can see
in Android is the recovery console, where a context may need to be set
on /system that is not defined in the recovery policy.
Remove these capabilities from unconfined domains, allow
mac_admin for the recovery domain, and add neverallow rules.
Change-Id: Ief673e12bc3caf695f3fb67cabe63e68f5f58150
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Require all domain transitions or dyntransitions to be
explicitly specified in SELinux policy.
healthd: Remove healthd_exec / init_daemon_domain().
Healthd lives on the rootfs and has no unique file type.
It should be treated consistent with other similar domains.
Change-Id: Ief3c1167379cfb5383073fa33c9a95710a883b29
The recovery console now has its own domain and therefore we do not
need to allow this for unconfined domains.
This reverts commit 43ddc10694.
Change-Id: Id2d2c02ccf6ac38c48b07ab84b73348cd9c815fa
The recovery console now has its own domain and therefore we do not
need to allow this for unconfined domains.
This reverts commit 89740a6967.
Change-Id: Ie060cff0de8cbd206e0e55e196021726e52246c7
As discussed in https://android-review.googlesource.com/78634 , the removal of execmem may cause OTA problems. Not sure...
Revert this patch to give us more time to investigate.
This reverts commit 4e416ea4ca.
Change-Id: Ie05f90235da5b9ee20b374298494cbc0a58b9b49
This ensures that only domains that are explicitly allowed executable
memory permissions are granted them.
Unconfined domains retain full write + execute access to all file
types. A further change could possibly restrict execute access to
a subset of file types, e.g. system_file + exec_type.
Change-Id: I842f5a2ac5921cc2bd0ab23a091eb808fdd89565
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Now that we set /sys/fs/selinux/checkreqprot via init.rc,
restrict the ability to set it to only the kernel domain.
Change-Id: I975061fd0e69c158db9bdb23e6ba77948e3fead1
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
init can't handle binder calls. It's always incorrect
to allow init:binder call, and represents a binder call
to a service without an SELinux domain. Adding this
allow rule was a mistake; the dumpstate SELinux domain didn't
exist at the time this rule was written, and dumpstate was
running under init's domain.
Add a neverallow rule to prevent the reintroduction of
this bug.
Change-Id: I78d35e675fd142d880f15329471778c18972bf50
Label /proc/sys/vm/mmap_min_addr with proc_security to prevent
writing it by any domain other than init. Also remove memprotect
mmap_zero permission from unconfineddomain so that it cannot pass
the SELinux check over mapping low memory.
Change-Id: Idc189feeb325a4aea26c93396fd0fa7225e79586
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Remove init, ueventd, watchdogd, healthd and adbd from the set of
domains traceable by debuggerd. bionic/linker/debugger.cpp sets up
handlers for all dynamically linked programs in Android but this
should not apply for statically linked programs.
Exclude ptrace access from unconfineddomain.
Prohibit ptrace access to init via neverallow.
Change-Id: I70d742233fbe40cb4d1772a4e6cd9f8f767f2c3a
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Limit the ability to write to the files that configure kernel
usermodehelpers and security-sensitive proc settings to the init domain.
Permissive domains can also continue to set these values.
The current list is not exhaustive, just an initial set.
Not all of these files will exist on all kernels/devices.
Controlling access to certain kernel usermodehelpers, e.g. cgroup
release_agent, will require kernel changes to support and cannot be
addressed here.
Expected output on e.g. flo after the change:
ls -Z /sys/kernel/uevent_helper /proc/sys/fs/suid_dumpable /proc/sys/kernel/core_pattern /proc/sys/kernel/dmesg_restrict /proc/sys/kernel/hotplug /proc/sys/kernel/kptr_restrict /proc/sys/kernel/poweroff_cmd /proc/sys/kernel/randomize_va_space /proc/sys/kernel/usermodehelper
-rw-r--r-- root root u:object_r:usermodehelper:s0 uevent_helper
-rw-r--r-- root root u:object_r:proc_security:s0 suid_dumpable
-rw-r--r-- root root u:object_r:usermodehelper:s0 core_pattern
-rw-r--r-- root root u:object_r:proc_security:s0 dmesg_restrict
-rw-r--r-- root root u:object_r:usermodehelper:s0 hotplug
-rw-r--r-- root root u:object_r:proc_security:s0 kptr_restrict
-rw-r--r-- root root u:object_r:usermodehelper:s0 poweroff_cmd
-rw-r--r-- root root u:object_r:proc_security:s0 randomize_va_space
-rw------- root root u:object_r:usermodehelper:s0 bset
-rw------- root root u:object_r:usermodehelper:s0 inheritable
Change-Id: I3f24b4bb90f0916ead863be6afd66d15ac5e8de0
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Also make su and shell permissive in non-user builds to allow
use of setenforce without violating the neverallow rule.
Change-Id: Ie76ee04e90d5a76dfaa5f56e9e3eb7e283328a3f
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
In https://android-review.googlesource.com/66562 , there
was a discussion about the role the unconfined template
plays. Document the unconfined template so that those
expectations are better understood.
Change-Id: I20ac01ac2d4496b8425b6f63d4106e8021bc9b2f
For unlabeled files, revert to DAC rules. This is for backwards
compatibility, as files created before SELinux was in place may
not be properly labeled.
Over time, the number of unlabeled files will decrease, and we can
(hopefully) remove this rule in the future.
To prevent inadvertantly introducing the "relabelto" permission, add
a neverallow domain, and add apps which have a legitimate need to
relabel to this domain.
Bug: 9777552
Change-Id: I71b0ff8abd4925432062007c45b5be85f6f70a88
This prevents denials from being generated by the base policy.
Over time, these rules will be incrementally tightened to improve
security.
Change-Id: I4be1c987a5d69ac784a56d42fc2c9063c402de11
The binder_transfer_binder hook was changed in the kernel, obsoleting
the receive permission and changing the target of the transfer permission.
Update the binder-related policy to match the revised permission checking.
Change-Id: I1ed0dadfde2efa93296e967eb44ca1314cf28586
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
New property_contexts file for property selabel backend.
New property.te file with property type declarations.
New property_service security class and set permission.
Allow rules for setting properties.
