Commit Graph

533 Commits

Author SHA1 Message Date
Linus Torvalds 8419639062 selinux/stable-5.12 PR 20210322
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Merge tag 'selinux-pr-20210322' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux fixes from Paul Moore:
 "Three SELinux patches:

   - Fix a problem where a local variable is used outside its associated
     function. Thankfully this can only be triggered by reloading the
     SELinux policy, which is a restricted operation for other obvious
     reasons.

   - Fix some incorrect, and inconsistent, audit and printk messages
     when loading the SELinux policy.

  All three patches are relatively minor and have been through our
  testing with no failures"

* tag 'selinux-pr-20210322' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinuxfs: unify policy load error reporting
  selinux: fix variable scope issue in live sidtab conversion
  selinux: don't log MAC_POLICY_LOAD record on failed policy load
2021-03-22 11:34:31 -07:00
Ondrej Mosnacek 6406887a12 selinux: fix variable scope issue in live sidtab conversion
Commit 02a52c5c8c ("selinux: move policy commit after updating
selinuxfs") moved the selinux_policy_commit() call out of
security_load_policy() into sel_write_load(), which caused a subtle yet
rather serious bug.

The problem is that security_load_policy() passes a reference to the
convert_params local variable to sidtab_convert(), which stores it in
the sidtab, where it may be accessed until the policy is swapped over
and RCU synchronized. Before 02a52c5c8c, selinux_policy_commit() was
called directly from security_load_policy(), so the convert_params
pointer remained valid all the way until the old sidtab was destroyed,
but now that's no longer the case and calls to sidtab_context_to_sid()
on the old sidtab after security_load_policy() returns may cause invalid
memory accesses.

This can be easily triggered using the stress test from commit
ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve
performance"):
```
function rand_cat() {
	echo $(( $RANDOM % 1024 ))
}

function do_work() {
	while true; do
		echo -n "system_u:system_r:kernel_t:s0:c$(rand_cat),c$(rand_cat)" \
			>/sys/fs/selinux/context 2>/dev/null || true
	done
}

do_work >/dev/null &
do_work >/dev/null &
do_work >/dev/null &

while load_policy; do echo -n .; sleep 0.1; done

kill %1
kill %2
kill %3
```

Fix this by allocating the temporary sidtab convert structures
dynamically and passing them among the
selinux_policy_{load,cancel,commit} functions.

Fixes: 02a52c5c8c ("selinux: move policy commit after updating selinuxfs")
Cc: stable@vger.kernel.org
Tested-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: merge fuzz in security.h and services.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-03-18 23:23:46 -04:00
Xiong Zhenwu 63ddf1baa0 selinux: fix misspellings using codespell tool
A typo is found out by codespell tool in 16th line of hashtab.c

$ codespell ./security/selinux/ss/
./hashtab.c:16: rouding  ==> rounding

Fix a typo found by codespell.

Signed-off-by: Xiong Zhenwu <xiong.zhenwu@zte.com.cn>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-03-08 19:44:30 -05:00
Lakshmi Ramasubramanian 2554a48f44 selinux: measure state and policy capabilities
SELinux stores the configuration state and the policy capabilities
in kernel memory.  Changes to this data at runtime would have an impact
on the security guarantees provided by SELinux.  Measuring this data
through IMA subsystem provides a tamper-resistant way for
an attestation service to remotely validate it at runtime.

Measure the configuration state and policy capabilities by calling
the IMA hook ima_measure_critical_data().

To enable SELinux data measurement, the following steps are required:

 1, Add "ima_policy=critical_data" to the kernel command line arguments
    to enable measuring SELinux data at boot time.
    For example,
      BOOT_IMAGE=/boot/vmlinuz-5.11.0-rc3+ root=UUID=fd643309-a5d2-4ed3-b10d-3c579a5fab2f ro nomodeset security=selinux ima_policy=critical_data

 2, Add the following rule to /etc/ima/ima-policy
       measure func=CRITICAL_DATA label=selinux

Sample measurement of SELinux state and policy capabilities:

10 2122...65d8 ima-buf sha256:13c2...1292 selinux-state 696e...303b

Execute the following command to extract the measured data
from the IMA's runtime measurements list:

  grep "selinux-state" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | tail -1 | cut -d' ' -f 6 | xxd -r -p

The output should be a list of key-value pairs. For example,
 initialized=1;enforcing=0;checkreqprot=1;network_peer_controls=1;open_perms=1;extended_socket_class=1;always_check_network=0;cgroup_seclabel=1;nnp_nosuid_transition=1;genfs_seclabel_symlinks=0;

To verify the measurement is consistent with the current SELinux state
reported on the system, compare the integer values in the following
files with those set in the IMA measurement (using the following commands):

 - cat /sys/fs/selinux/enforce
 - cat /sys/fs/selinux/checkreqprot
 - cat /sys/fs/selinux/policy_capabilities/[capability_file]

Note that the actual verification would be against an expected state
and done on a separate system (likely an attestation server) requiring
"initialized=1;enforcing=1;checkreqprot=0;"
for a secure state and then whatever policy capabilities are actually
set in the expected policy (which can be extracted from the policy
itself via seinfo, for example).

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-03-08 19:39:07 -05:00
Linus Torvalds d643a99089 integrity-v5.12
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Merge tag 'integrity-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

Pull IMA updates from Mimi Zohar:
 "New is IMA support for measuring kernel critical data, as per usual
  based on policy. The first example measures the in memory SELinux
  policy. The second example measures the kernel version.

  In addition are four bug fixes to address memory leaks and a missing
  'static' function declaration"

* tag 'integrity-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  integrity: Make function integrity_add_key() static
  ima: Free IMA measurement buffer after kexec syscall
  ima: Free IMA measurement buffer on error
  IMA: Measure kernel version in early boot
  selinux: include a consumer of the new IMA critical data hook
  IMA: define a builtin critical data measurement policy
  IMA: extend critical data hook to limit the measurement based on a label
  IMA: limit critical data measurement based on a label
  IMA: add policy rule to measure critical data
  IMA: define a hook to measure kernel integrity critical data
  IMA: add support to measure buffer data hash
  IMA: generalize keyring specific measurement constructs
  evm: Fix memleak in init_desc
2021-02-21 17:08:06 -08:00
Lakshmi Ramasubramanian fdd1ffe8a8 selinux: include a consumer of the new IMA critical data hook
SELinux stores the active policy in memory, so the changes to this data
at runtime would have an impact on the security guarantees provided
by SELinux.  Measuring in-memory SELinux policy through IMA subsystem
provides a secure way for the attestation service to remotely validate
the policy contents at runtime.

Measure the hash of the loaded policy by calling the IMA hook
ima_measure_critical_data().  Since the size of the loaded policy
can be large (several MB), measure the hash of the policy instead of
the entire policy to avoid bloating the IMA log entry.

To enable SELinux data measurement, the following steps are required:

1, Add "ima_policy=critical_data" to the kernel command line arguments
   to enable measuring SELinux data at boot time.
For example,
  BOOT_IMAGE=/boot/vmlinuz-5.10.0-rc1+ root=UUID=fd643309-a5d2-4ed3-b10d-3c579a5fab2f ro nomodeset security=selinux ima_policy=critical_data

2, Add the following rule to /etc/ima/ima-policy
   measure func=CRITICAL_DATA label=selinux

Sample measurement of the hash of SELinux policy:

To verify the measured data with the current SELinux policy run
the following commands and verify the output hash values match.

  sha256sum /sys/fs/selinux/policy | cut -d' ' -f 1

  grep "selinux-policy-hash" /sys/kernel/security/integrity/ima/ascii_runtime_measurements | tail -1 | cut -d' ' -f 6

Note that the actual verification of SELinux policy would require loading
the expected policy into an identical kernel on a pristine/known-safe
system and run the sha256sum /sys/kernel/selinux/policy there to get
the expected hash.

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-01-14 23:41:46 -05:00
Ondrej Mosnacek cd2bb4cb09 selinux: mark some global variables __ro_after_init
All of these are never modified outside initcalls, so they can be
__ro_after_init.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-01-12 10:08:55 -05:00
Ondrej Mosnacek 3c797e514b selinux: drop the unnecessary aurule_callback variable
Its value is actually not changed anywhere, so it can be substituted for
a direct call to audit_update_lsm_rules().

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-01-12 09:53:57 -05:00
bauen1 44141f58e1 selinux: allow dontauditx and auditallowx rules to take effect without allowx
This allows for dontauditing very specific ioctls e.g. TCGETS without
dontauditing every ioctl or granting additional permissions.

Now either an allowx, dontauditx or auditallowx rules enables checking
for extended permissions.

Signed-off-by: Jonathan Hettwer <j2468h@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-10-27 22:21:11 -04:00
Linus Torvalds 7b540812cc selinux/stable-5.10 PR 20201012
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Merge tag 'selinux-pr-20201012' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "A decent number of SELinux patches for v5.10, twenty two in total. The
  highlights are listed below, but all of the patches pass our test
  suite and merge cleanly.

   - A number of changes to how the SELinux policy is loaded and managed
     inside the kernel with the goal of improving the atomicity of a
     SELinux policy load operation.

     These changes account for the bulk of the diffstat as well as the
     patch count. A special thanks to everyone who contributed patches
     and fixes for this work.

   - Convert the SELinux policy read-write lock to RCU.

   - A tracepoint was added for audited SELinux access control events;
     this should help provide a more unified backtrace across kernel and
     userspace.

   - Allow the removal of security.selinux xattrs when a SELinux policy
     is not loaded.

   - Enable policy capabilities in SELinux policies created with the
     scripts/selinux/mdp tool.

   - Provide some "no sooner than" dates for the SELinux checkreqprot
     sysfs deprecation"

* tag 'selinux-pr-20201012' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: (22 commits)
  selinux: provide a "no sooner than" date for the checkreqprot removal
  selinux: Add helper functions to get and set checkreqprot
  selinux: access policycaps with READ_ONCE/WRITE_ONCE
  selinux: simplify away security_policydb_len()
  selinux: move policy mutex to selinux_state, use in lockdep checks
  selinux: fix error handling bugs in security_load_policy()
  selinux: convert policy read-write lock to RCU
  selinux: delete repeated words in comments
  selinux: add basic filtering for audit trace events
  selinux: add tracepoint on audited events
  selinux: Create new booleans and class dirs out of tree
  selinux: Standardize string literal usage for selinuxfs directory names
  selinux: Refactor selinuxfs directory populating functions
  selinux: Create function for selinuxfs directory cleanup
  selinux: permit removing security.selinux xattr before policy load
  selinux: fix memdup.cocci warnings
  selinux: avoid dereferencing the policy prior to initialization
  selinux: fix allocation failure check on newpolicy->sidtab
  selinux: refactor changing booleans
  selinux: move policy commit after updating selinuxfs
  ...
2020-10-13 16:29:55 -07:00
Stephen Smalley e8ba53d002 selinux: access policycaps with READ_ONCE/WRITE_ONCE
Use READ_ONCE/WRITE_ONCE for all accesses to the
selinux_state.policycaps booleans to prevent compiler
mischief.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-09-11 10:08:51 -04:00
Ondrej Mosnacek 66ccd2560a selinux: simplify away security_policydb_len()
Remove the security_policydb_len() calls from sel_open_policy() and
instead update the inode size from the size returned from
security_read_policy().

Since after this change security_policydb_len() is only called from
security_load_policy(), remove it entirely and just open-code it there.

Also, since security_load_policy() is always called with policy_mutex
held, make it dereference the policy pointer directly and drop the
unnecessary RCU locking.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-31 10:00:14 -04:00
Stephen Smalley 9ff9abc4c6 selinux: move policy mutex to selinux_state, use in lockdep checks
Move the mutex used to synchronize policy changes (reloads and setting
of booleans) from selinux_fs_info to selinux_state and use it in
lockdep checks for rcu_dereference_protected() calls in the security
server functions.  This makes the dependency on the mutex explicit
in the code rather than relying on comments.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-27 09:52:47 -04:00
Dan Carpenter 0256b0aa80 selinux: fix error handling bugs in security_load_policy()
There are a few bugs in the error handling for security_load_policy().

1) If the newpolicy->sidtab allocation fails then it leads to a NULL
   dereference.  Also the error code was not set to -ENOMEM on that
   path.
2) If policydb_read() failed then we call policydb_destroy() twice
   which meands we call kvfree(p->sym_val_to_name[i]) twice.
3) If policydb_load_isids() failed then we call sidtab_destroy() twice
   and that results in a double free in the sidtab_destroy_tree()
   function because entry.ptr_inner and entry.ptr_leaf are not set to
   NULL.

One thing that makes this code nice to deal with is that none of the
functions return partially allocated data.  In other words, the
policydb_read() either allocates everything successfully or it frees
all the data it allocates.  It never returns a mix of allocated and
not allocated data.

I re-wrote this to only free the successfully allocated data which
avoids the double frees.  I also re-ordered selinux_policy_free() so
it's in the reverse order of the allocation function.

Fixes: c7c556f1e8 ("selinux: refactor changing booleans")
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
[PM: partially merged by hand due to merge fuzz]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-26 10:19:08 -04:00
Stephen Smalley 1b8b31a2e6 selinux: convert policy read-write lock to RCU
Convert the policy read-write lock to RCU.  This is significantly
simplified by the earlier work to encapsulate the policy data
structures and refactor the policy load and boolean setting logic.
Move the latest_granting sequence number into the selinux_policy
structure so that it can be updated atomically with the policy.
Since removing the policy rwlock and moving latest_granting reduces
the selinux_ss structure to nothing more than a wrapper around the
selinux_policy pointer, get rid of the extra layer of indirection.

At present this change merely passes a hardcoded 1 to
rcu_dereference_check() in the cases where we know we do not need to
take rcu_read_lock(), with the preceding comment explaining why.
Alternatively we could pass fsi->mutex down from selinuxfs and
apply a lockdep check on it instead.

Based in part on earlier attempts to convert the policy rwlock
to RCU by Kaigai Kohei [1] and by Peter Enderborg [2].

[1] https://lore.kernel.org/selinux/6e2f9128-e191-ebb3-0e87-74bfccb0767f@tycho.nsa.gov/
[2] https://lore.kernel.org/selinux/20180530141104.28569-1-peter.enderborg@sony.com/

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-25 08:34:47 -04:00
Gustavo A. R. Silva df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
kernel test robot 879229311b selinux: fix memdup.cocci warnings
Use kmemdup rather than duplicating its implementation

Generated by: scripts/coccinelle/api/memdup.cocci

Fixes: c7c556f1e8 ("selinux: refactor changing booleans")
CC: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-20 08:39:05 -04:00
Stephen Smalley 37ea433c66 selinux: avoid dereferencing the policy prior to initialization
Certain SELinux security server functions (e.g. security_port_sid,
called during bind) were not explicitly testing to see if SELinux
has been initialized (i.e. initial policy loaded) and handling
the no-policy-loaded case.  In the past this happened to work
because the policydb was statically allocated and could always
be accessed, but with the recent encapsulation of policy state
and conversion to dynamic allocation, we can no longer access
the policy state prior to initialization.  Add a test of
!selinux_initialized(state) to all of the exported functions that
were missing them and handle appropriately.

Fixes: 461698026f ("selinux: encapsulate policy state, refactor policy load")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-19 21:14:41 -04:00
Colin Ian King 69ea651c40 selinux: fix allocation failure check on newpolicy->sidtab
The allocation check of newpolicy->sidtab is null checking if
newpolicy is null and not newpolicy->sidtab. Fix this.

Addresses-Coverity: ("Logically dead code")
Fixes: c7c556f1e8 ("selinux: refactor changing booleans")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-19 09:14:04 -04:00
Stephen Smalley c7c556f1e8 selinux: refactor changing booleans
Refactor the logic for changing SELinux policy booleans in a similar
manner to the refactoring of policy load, thereby reducing the
size of the critical section when the policy write-lock is held
and making it easier to convert the policy rwlock to RCU in the
future.  Instead of directly modifying the policydb in place, modify
a copy and then swap it into place through a single pointer update.
Only fully copy the portions of the policydb that are affected by
boolean changes to avoid the full cost of a deep policydb copy.
Introduce another level of indirection for the sidtab since changing
booleans does not require updating the sidtab, unlike policy load.
While we are here, create a common helper for notifying
other kernel components and userspace of a policy change and call it
from both security_set_bools() and selinux_policy_commit().

Based on an old (2004) patch by Kaigai Kohei [1] to convert the policy
rwlock to RCU that was deferred at the time since it did not
significantly improve performance and introduced complexity. Peter
Enderborg later submitted a patch series to convert to RCU [2] that
would have made changing booleans a much more expensive operation
by requiring a full policydb_write();policydb_read(); sequence to
deep copy the entire policydb and also had concerns regarding
atomic allocations.

This change is now simplified by the earlier work to encapsulate
policy state in the selinux_policy struct and to refactor
policy load.  After this change, the last major obstacle to
converting the policy rwlock to RCU is likely the sidtab live
convert support.

[1] https://lore.kernel.org/selinux/6e2f9128-e191-ebb3-0e87-74bfccb0767f@tycho.nsa.gov/
[2] https://lore.kernel.org/selinux/20180530141104.28569-1-peter.enderborg@sony.com/

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-17 21:00:33 -04:00
Stephen Smalley 02a52c5c8c selinux: move policy commit after updating selinuxfs
With the refactoring of the policy load logic in the security
server from the previous change, it is now possible to split out
the committing of the new policy from security_load_policy() and
perform it only after successful updating of selinuxfs.  Change
security_load_policy() to return the newly populated policy
data structures to the caller, export selinux_policy_commit()
for external callers, and introduce selinux_policy_cancel() to
provide a way to cancel the policy load in the event of an error
during updating of the selinuxfs directory tree.  Further, rework
the interfaces used by selinuxfs to get information from the policy
when creating the new directory tree to take and act upon the
new policy data structure rather than the current/active policy.
Update selinuxfs to use these updated and new interfaces.  While
we are here, stop re-creating the policy_capabilities directory
on each policy load since it does not depend on the policy, and
stop trying to create the booleans and classes directories during
the initial creation of selinuxfs since no information is available
until first policy load.

After this change, a failure while updating the booleans and class
directories will cause the entire policy load to be canceled, leaving
the original policy intact, and policy load notifications to userspace
will only happen after a successful completion of updating those
directories.  This does not (yet) provide full atomicity with respect
to the updating of the directory trees themselves.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-17 20:50:22 -04:00
Stephen Smalley 461698026f selinux: encapsulate policy state, refactor policy load
Encapsulate the policy state in its own structure (struct
selinux_policy) that is separately allocated but referenced from the
selinux_ss structure.  The policy state includes the SID table
(particularly the context structures), the policy database, and the
mapping between the kernel classes/permissions and the policy values.
Refactor the security server portion of the policy load logic to
cleanly separate loading of the new structures from committing the new
policy.  Unify the initial policy load and reload code paths as much
as possible, avoiding duplicated code.  Make sure we are taking the
policy read-lock prior to any dereferencing of the policy.  Move the
copying of the policy capability booleans into the state structure
outside of the policy write-lock because they are separate from the
policy and are read outside of any policy lock; possibly they should
be using at least READ_ONCE/WRITE_ONCE or smp_load_acquire/store_release.

These changes simplify the policy loading logic, reduce the size of
the critical section while holding the policy write-lock, and should
facilitate future changes to e.g. refactor the entire policy reload
logic including the selinuxfs code to make the updating of the policy
and the selinuxfs directory tree atomic and/or to convert the policy
read-write lock to RCU.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-17 20:48:57 -04:00
Stephen Smalley 339949be25 scripts/selinux,selinux: update mdp to enable policy capabilities
Presently mdp does not enable any SELinux policy capabilities
in the dummy policy it generates. Thus, policies derived from
it will by default lack various features commonly used in modern
policies such as open permission, extended socket classes, network
peer controls, etc.  Split the policy capability definitions out into
their own headers so that we can include them into mdp without pulling in
other kernel headers and extend mdp generate policycap statements for the
policy capabilities known to the kernel.  Policy authors may wish to
selectively remove some of these from the generated policy.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-08-17 20:42:00 -04:00
Linus Torvalds 49e917deeb selinux/stable-5.9 PR 20200803
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Merge tag 'selinux-pr-20200803' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "Beyond the usual smattering of bug fixes, we've got three small
  improvements worth highlighting:

   - improved SELinux policy symbol table performance due to a reworking
     of the insert and search functions

   - allow reading of SELinux labels before the policy is loaded,
     allowing for some more "exotic" initramfs approaches

   - improved checking an error reporting about process
     class/permissions during SELinux policy load"

* tag 'selinux-pr-20200803' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: complete the inlining of hashtab functions
  selinux: prepare for inlining of hashtab functions
  selinux: specialize symtab insert and search functions
  selinux: Fix spelling mistakes in the comments
  selinux: fixed a checkpatch warning with the sizeof macro
  selinux: log error messages on required process class / permissions
  scripts/selinux/mdp: fix initial SID handling
  selinux: allow reading labels before policy is loaded
2020-08-04 14:18:01 -07:00
Ondrej Mosnacek 54b27f9287 selinux: complete the inlining of hashtab functions
Move (most of) the definitions of hashtab_search() and hashtab_insert()
to the header file. In combination with the previous patch, this avoids
calling the callbacks indirectly by function pointers and allows for
better optimization, leading to a drastic performance improvement of
these operations.

With this patch, I measured a speed up in the following areas (measured
on x86_64 F32 VM with 4 CPUs):
  1. Policy load (`load_policy`) - takes ~150 ms instead of ~230 ms.
  2. `chcon -R unconfined_u:object_r:user_tmp_t:s0:c381,c519 /tmp/linux-src`
     where /tmp/linux-src is an extracted linux-5.7 source tarball -
     takes ~522 ms instead of ~576 ms. This is because of many
     symtab_search() calls in string_to_context_struct() when there are
     many categories specified in the context.
  3. `stress-ng --msg 1 --msg-ops 10000000` - takes 12.41 s instead of
     13.95 s (consumes 18.6 s of kernel CPU time instead of 21.6 s).
     This is thanks to security_transition_sid() being ~43% faster after
     this patch.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-07-09 19:08:16 -04:00
Ondrej Mosnacek 24def7bb92 selinux: prepare for inlining of hashtab functions
Refactor searching and inserting into hashtabs to pave the way for
converting hashtab_search() and hashtab_insert() to inline functions in
the next patch. This will avoid indirect calls and allow the compiler to
better optimize individual callers, leading to a significant performance
improvement.

In order to avoid the indirect calls, the key hashing and comparison
callbacks need to be extracted from the hashtab struct and passed
directly to hashtab_search()/_insert() by the callers so that the
callback address is always known at compile time. The kernel's
rhashtable library (<linux/rhashtable*.h>) does the same thing.

This of course makes the hashtab functions slightly easier to misuse by
passing a wrong callback set, but unfortunately there is no better way
to implement a hash table that is both generic and efficient in C. This
patch tries to somewhat mitigate this by only calling the hashtab
functions in the same file where the corresponding callbacks are
defined (wrapping them into more specialized functions as needed).

Note that this patch doesn't bring any benefit without also moving the
definitions of hashtab_search() and -_insert() to the header file, which
is done in a follow-up patch for easier review of the hashtab.c changes
in this patch.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-07-09 19:05:36 -04:00
Ondrej Mosnacek 237389e301 selinux: specialize symtab insert and search functions
This encapsulates symtab a little better and will help with further
refactoring later.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-07-08 20:21:43 -04:00
Ethan Edwards 65d96351b1 selinux: fixed a checkpatch warning with the sizeof macro
`sizeof buf` changed to `sizeof(buf)`

Signed-off-by: Ethan Edwards <ethancarteredwards@gmail.com>
[PM: rewrote the subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-29 19:26:17 -04:00
Stephen Smalley 7383c0f94d selinux: log error messages on required process class / permissions
In general SELinux no longer treats undefined object classes or permissions
in the policy as a fatal error, instead handling them in accordance with
handle_unknown. However, the process class and process transition and
dyntransition permissions are still required to be defined due to
dependencies on these definitions for default labeling behaviors,
role and range transitions in older policy versions that lack an explicit
class field, and role allow checking.  Log error messages in these cases
since otherwise the policy load will fail silently with no indication
to the user as to the underlying cause.  While here, fix the checking for
process transition / dyntransition so that omitting either permission is
handled as an error; both are needed in order to ensure that role allow
checking is consistently applied.

Reported-by: bauen1 <j2468h@googlemail.com>
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-23 20:57:01 -04:00
Linus Torvalds 817d914d17 selinux/stable-5.8 PR 20200621
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Merge tag 'selinux-pr-20200621' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull SELinux fixes from Paul Moore:
 "Three small patches to fix problems in the SELinux code, all found via
  clang.

  Two patches fix potential double-free conditions and one fixes an
  undefined return value"

* tag 'selinux-pr-20200621' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: fix undefined return of cond_evaluate_expr
  selinux: fix a double free in cond_read_node()/cond_read_list()
  selinux: fix double free
2020-06-21 15:41:24 -07:00
Tom Rix 8231b0b9c3 selinux: fix undefined return of cond_evaluate_expr
clang static analysis reports an undefined return

security/selinux/ss/conditional.c:79:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn]
        return s[0];
        ^~~~~~~~~~~

static int cond_evaluate_expr( ...
{
	u32 i;
	int s[COND_EXPR_MAXDEPTH];

	for (i = 0; i < expr->len; i++)
	  ...

	return s[0];

When expr->len is 0, the loop which sets s[0] never runs.

So return -1 if the loop never runs.

Cc: stable@vger.kernel.org
Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-17 17:36:40 -04:00
Tom Rix aa449a7965 selinux: fix a double free in cond_read_node()/cond_read_list()
Clang static analysis reports this double free error

security/selinux/ss/conditional.c:139:2: warning: Attempt to free released memory [unix.Malloc]
        kfree(node->expr.nodes);
        ^~~~~~~~~~~~~~~~~~~~~~~

When cond_read_node fails, it calls cond_node_destroy which frees the
node but does not poison the entry in the node list.  So when it
returns to its caller cond_read_list, cond_read_list deletes the
partial list.  The latest entry in the list will be deleted twice.

So instead of freeing the node in cond_read_node, let list freeing in
code_read_list handle the freeing the problem node along with all of the
earlier nodes.

Because cond_read_node no longer does any error handling, the goto's
the error case are redundant.  Instead just return the error code.

Cc: stable@vger.kernel.org
Fixes: 60abd3181d ("selinux: convert cond_list to array")
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-16 20:25:19 -04:00
Tom Rix 65de50969a selinux: fix double free
Clang's static analysis tool reports these double free memory errors.

security/selinux/ss/services.c:2987:4: warning: Attempt to free released memory [unix.Malloc]
                        kfree(bnames[i]);
                        ^~~~~~~~~~~~~~~~
security/selinux/ss/services.c:2990:2: warning: Attempt to free released memory [unix.Malloc]
        kfree(bvalues);
        ^~~~~~~~~~~~~~

So improve the security_get_bools error handling by freeing these variables
and setting their return pointers to NULL and the return len to 0

Cc: stable@vger.kernel.org
Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-06-10 22:10:35 -04:00
Linus Torvalds f41030a20b selinux/stable-5.8 PR 20200601
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Merge tag 'selinux-pr-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull SELinux updates from Paul Moore:
 "The highlights:

   - A number of improvements to various SELinux internal data
     structures to help improve performance. We move the role
     transitions into a hash table. In the content structure we shift
     from hashing the content string (aka SELinux label) to the
     structure itself, when it is valid. This last change not only
     offers a speedup, but it helps us simplify the code some as well.

   - Add a new SELinux policy version which allows for a more space
     efficient way of storing the filename transitions in the binary
     policy. Given the default Fedora SELinux policy with the unconfined
     module enabled, this change drops the policy size from ~7.6MB to
     ~3.3MB. The kernel policy load time dropped as well.

   - Some fixes to the error handling code in the policy parser to
     properly return error codes when things go wrong"

* tag 'selinux-pr-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: netlabel: Remove unused inline function
  selinux: do not allocate hashtabs dynamically
  selinux: fix return value on error in policydb_read()
  selinux: simplify range_write()
  selinux: fix error return code in policydb_read()
  selinux: don't produce incorrect filename_trans_count
  selinux: implement new format of filename transitions
  selinux: move context hashing under sidtab
  selinux: hash context structure directly
  selinux: store role transitions in a hash table
  selinux: drop unnecessary smp_load_acquire() call
  selinux: fix warning Comparison to bool
2020-06-02 17:16:47 -07:00
Ondrej Mosnacek 03414a49ad selinux: do not allocate hashtabs dynamically
It is simpler to allocate them statically in the corresponding
structure, avoiding unnecessary kmalloc() calls and pointer
dereferencing.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: manual merging required in policydb.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-05-01 16:34:57 -04:00
Ondrej Mosnacek 46619b44e4 selinux: fix return value on error in policydb_read()
The value of rc is still zero from the last assignment when the error
path is taken. Fix it by setting it to -ENOMEM before the
hashtab_create() call.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: e67b2ec9f6 ("selinux: store role transitions in a hash table")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-05-01 16:08:46 -04:00
Ondrej Mosnacek 3348bd33e8 selinux: simplify range_write()
No need to traverse the hashtab to count its elements, hashtab already
tracks it for us.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-05-01 16:08:04 -04:00
Wei Yongjun 4c09f8b691 selinux: fix error return code in policydb_read()
Fix to return negative error code -ENOMEM from the kvcalloc() error
handling case instead of 0, as done elsewhere in this function.

Fixes: acdf52d97f ("selinux: convert to kvmalloc")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-05-01 15:02:14 -04:00
Linus Torvalds 39e16d9342 selinux/stable-5.7 PR 20200430
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Merge tag 'selinux-pr-20200430' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull SELinux fixes from Paul Moore:
 "Two more SELinux patches to fix problems in the v5.7-rcX releases.

  Wei Yongjun's patch fixes a return code in an error path, and my patch
  fixes a problem where we were not correctly applying access controls
  to all of the netlink messages in the netlink_send LSM hook"

* tag 'selinux-pr-20200430' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: properly handle multiple messages in selinux_netlink_send()
  selinux: fix error return code in cond_read_list()
2020-04-30 16:35:45 -07:00
Wei Yongjun 292fed1fc8 selinux: fix error return code in cond_read_list()
Fix to return negative error code -ENOMEM from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 60abd3181d ("selinux: convert cond_list to array")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-27 17:44:39 -04:00
Ondrej Mosnacek 9521eb3ea1 selinux: don't produce incorrect filename_trans_count
I thought I fixed the counting in filename_trans_read_helper() to count
the compat rule count correctly in the final version, but it's still
wrong. To really count the same thing as in the compat path, we'd need
to add up the cardinalities of stype bitmaps of all datums.

Since the kernel currently doesn't implement an ebitmap_cardinality()
function (and computing the proper count would just waste CPU cycles
anyway), just document that we use the field only in case of the old
format and stop updating it in filename_trans_read_helper().

Fixes: 4300590243 ("selinux: implement new format of filename transitions")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-22 15:38:10 -04:00
Ondrej Mosnacek 4300590243 selinux: implement new format of filename transitions
Implement a new, more space-efficient way of storing filename
transitions in the binary policy. The internal structures have already
been converted to this new representation; this patch just implements
reading/writing an equivalent represntation from/to the binary policy.

This new format reduces the size of Fedora policy from 7.6 MB to only
3.3 MB (with policy optimization enabled in both cases). With the
unconfined module disabled, the size is reduced from 3.3 MB to 2.4 MB.

The time to load policy into kernel is also shorter with the new format.
On Fedora Rawhide x86_64 it dropped from 157 ms to 106 ms; without the
unconfined module from 115 ms to 105 ms.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-17 16:42:01 -04:00
Ondrej Mosnacek 225621c934 selinux: move context hashing under sidtab
Now that context hash computation no longer depends on policydb, we can
simplify things by moving the context hashing completely under sidtab.
The hash is still cached in sidtab entries, but not for the in-flight
context structures.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-17 16:04:38 -04:00
Ondrej Mosnacek 5007728980 selinux: hash context structure directly
Always hashing the string representation is inefficient. Just hash the
contents of the structure directly (using jhash). If the context is
invalid (str & len are set), then hash the string as before, otherwise
hash the structured data.

Since the context hashing function is now faster (about 10 times), this
patch decreases the overhead of security_transition_sid(), which is
called from many hooks.

The jhash function seemed as a good choice, since it is used as the
default hashing algorithm in rhashtable.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Jeff Vander Stoep <jeffv@google.com>
Tested-by: Jeff Vander Stoep <jeffv@google.com>
[PM: fixed some spelling errors in the comments pointed out by JVS]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-17 16:04:34 -04:00
Ondrej Mosnacek e67b2ec9f6 selinux: store role transitions in a hash table
Currently, they are stored in a linked list, which adds significant
overhead to security_transition_sid(). On Fedora, with 428 role
transitions in policy, converting this list to a hash table cuts down
its run time by about 50%. This was measured by running 'stress-ng --msg
1 --msg-ops 100000' under perf with and without this patch.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-17 15:20:22 -04:00
Linus Torvalds 9786cab674 selinux/stable-5.7 PR 20200416
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Merge tag 'selinux-pr-20200416' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull SELinux fix from Paul Moore:
 "One small SELinux fix to ensure we cleanup properly on an error
  condition"

* tag 'selinux-pr-20200416' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: free str on error in str_read()
2020-04-16 10:45:47 -07:00
Ondrej Mosnacek 433e3aa377 selinux: drop unnecessary smp_load_acquire() call
In commit 66f8e2f03c ("selinux: sidtab reverse lookup hash table") the
corresponding load is moved under the spin lock, so there is no race
possible and we can read the count directly. The smp_store_release() is
still needed to avoid racing with the lock-free readers.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-15 18:27:35 -04:00
Ondrej Mosnacek af15f14c8c selinux: free str on error in str_read()
In [see "Fixes:"] I missed the fact that str_read() may give back an
allocated pointer even if it returns an error, causing a potential
memory leak in filename_trans_read_one(). Fix this by making the
function free the allocated string whenever it returns a non-zero value,
which also makes its behavior more obvious and prevents repeating the
same mistake in the future.

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1461665 ("Resource leaks")
Fixes: c3a276111e ("selinux: optimize storage of filename transitions")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-15 17:23:16 -04:00
Zou Wei 4b8503967e selinux: fix warning Comparison to bool
fix below warnings reported by coccicheck

security/selinux/ss/mls.c:539:39-43: WARNING: Comparison to bool
security/selinux/ss/services.c:1815:46-50: WARNING: Comparison to bool
security/selinux/ss/services.c:1827:46-50: WARNING: Comparison to bool

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-04-14 18:01:18 -04:00
Linus Torvalds b3aa112d57 selinux/stable-5.7 PR 20200330
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Merge tag 'selinux-pr-20200330' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull SELinux updates from Paul Moore:
 "We've got twenty SELinux patches for the v5.7 merge window, the
  highlights are below:

   - Deprecate setting /sys/fs/selinux/checkreqprot to 1.

     This flag was originally created to deal with legacy userspace and
     the READ_IMPLIES_EXEC personality flag. We changed the default from
     1 to 0 back in Linux v4.4 and now we are taking the next step of
     deprecating it, at some point in the future we will take the final
     step of rejecting 1.

   - Allow kernfs symlinks to inherit the SELinux label of the parent
     directory. In order to preserve backwards compatibility this is
     protected by the genfs_seclabel_symlinks SELinux policy capability.

   - Optimize how we store filename transitions in the kernel, resulting
     in some significant improvements to policy load times.

   - Do a better job calculating our internal hash table sizes which
     resulted in additional policy load improvements and likely general
     SELinux performance improvements as well.

   - Remove the unused initial SIDs (labels) and improve how we handle
     initial SIDs.

   - Enable per-file labeling for the bpf filesystem.

   - Ensure that we properly label NFS v4.2 filesystems to avoid a
     temporary unlabeled condition.

   - Add some missing XFS quota command types to the SELinux quota
     access controls.

   - Fix a problem where we were not updating the seq_file position
     index correctly in selinuxfs.

   - We consolidate some duplicated code into helper functions.

   - A number of list to array conversions.

   - Update Stephen Smalley's email address in MAINTAINERS"

* tag 'selinux-pr-20200330' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: clean up indentation issue with assignment statement
  NFS: Ensure security label is set for root inode
  MAINTAINERS: Update my email address
  selinux: avtab_init() and cond_policydb_init() return void
  selinux: clean up error path in policydb_init()
  selinux: remove unused initial SIDs and improve handling
  selinux: reduce the use of hard-coded hash sizes
  selinux: Add xfs quota command types
  selinux: optimize storage of filename transitions
  selinux: factor out loop body from filename_trans_read()
  security: selinux: allow per-file labeling for bpffs
  selinux: generalize evaluate_cond_node()
  selinux: convert cond_expr to array
  selinux: convert cond_av_list to array
  selinux: convert cond_list to array
  selinux: sel_avc_get_stat_idx should increase position index
  selinux: allow kernfs symlinks to inherit parent directory context
  selinux: simplify evaluate_cond_node()
  Documentation,selinux: deprecate setting checkreqprot to 1
  selinux: move status variables out of selinux_ss
2020-03-31 15:07:55 -07:00
Colin Ian King c753924b62 selinux: clean up indentation issue with assignment statement
The assignment of e->type_names is indented one level too deep,
clean this up by removing the extraneous tab.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-03-30 19:57:07 -04:00
Paul Moore 5e729e111e selinux: avtab_init() and cond_policydb_init() return void
The avtab_init() and cond_policydb_init() functions always return
zero so mark them as returning void and update the callers not to
check for a return value.

Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-03-05 14:55:43 -05:00
Ondrej Mosnacek 34a2dab488 selinux: clean up error path in policydb_init()
Commit e0ac568de1 ("selinux: reduce the use of hard-coded hash sizes")
moved symtab initialization out of policydb_init(), but left the cleanup
of symtabs from the error path. This patch fixes the oversight.

Suggested-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-03-05 14:49:15 -05:00
Stephen Smalley e3e0b582c3 selinux: remove unused initial SIDs and improve handling
Remove initial SIDs that have never been used or are no longer used by
the kernel from its string table, which is also used to generate the
SECINITSID_* symbols referenced in code.  Update the code to
gracefully handle the fact that these can now be NULL. Stop treating
it as an error if a policy defines additional initial SIDs unknown to
the kernel.  Do not load unused initial SID contexts into the sidtab.
Fix the incorrect usage of the name from the ocontext in error
messages when loading initial SIDs since these are not presently
written to the kernel policy and are therefore always NULL.

After this change, it is possible to safely reclaim and reuse some of
the unused initial SIDs without compatibility issues.  Specifically,
unused initial SIDs that were being assigned the same context as the
unlabeled initial SID in policies can be reclaimed and reused for
another purpose, with existing policies still treating them as having
the unlabeled context and future policies having the option of mapping
them to a more specific context.  For example, this could have been
used when the infiniband labeling support was introduced to define
initial SIDs for the default pkey and endport SIDs similar to the
handling of port/netif/node SIDs rather than always using
SECINITSID_UNLABELED as the default.

The set of safely reclaimable unused initial SIDs across all known
policies is igmp_packet (13), icmp_socket (14), tcp_socket (15), kmod
(24), policy (25), and scmp_packet (26); these initial SIDs were
assigned the same context as unlabeled in all known policies including
mls.  If only considering non-mls policies (i.e. assuming that mls
users always upgrade policy with their kernels), the set of safely
reclaimable unused initial SIDs further includes file_labels (6), init
(7), sysctl_modprobe (16), and sysctl_fs (18) through sysctl_dev (23).

Adding new initial SIDs beyond SECINITSID_NUM to policy unfortunately
became a fatal error in commit 24ed7fdae6 ("selinux: use separate
table for initial SID lookup") and even before that it could cause
problems on a policy reload (collision between the new initial SID and
one allocated at runtime) ever since commit 42596eafdd ("selinux:
load the initial SIDs upon every policy load") so we cannot safely
start adding new initial SIDs to policies beyond SECINITSID_NUM (27)
until such a time as all such kernels do not need to be supported and
only those that include this commit are relevant. That is not a big
deal since we haven't added a new initial SID since 2004 (v2.6.7) and
we have plenty of unused ones we can reclaim if we truly need one.

If we want to avoid the wasted storage in initial_sid_to_string[]
and/or sidtab->isids[] for the unused initial SIDs, we could introduce
an indirection between the kernel initial SID values and the policy
initial SID values and just map the policy SID values in the ocontexts
to the kernel values during policy_load_isids(). Originally I thought
we'd do this by preserving the initial SID names in the kernel policy
and creating a mapping at load time like we do for the security
classes and permissions but that would require a new kernel policy
format version and associated changes to libsepol/checkpolicy and I'm
not sure it is justified. Simpler approach is just to create a fixed
mapping table in the kernel from the existing fixed policy values to
the kernel values. Less flexible but probably sufficient.

A separate selinux userspace change was applied in
8677ce5e8f
to enable removal of most of the unused initial SID contexts from
policies, but there is no dependency between that change and this one.
That change permits removing all of the unused initial SID contexts
from policy except for the fs and sysctl SID contexts.  The initial
SID declarations themselves would remain in policy to preserve the
values of subsequent ones but the contexts can be dropped.  If/when
the kernel decides to reuse one of them, future policies can change
the name and start assigning a context again without breaking
compatibility.

Here is how I would envision staging changes to the initial SIDs in a
compatible manner after this commit is applied:

1. At any time after this commit is applied, the kernel could choose
to reclaim one of the safely reclaimable unused initial SIDs listed
above for a new purpose (i.e. replace its NULL entry in the
initial_sid_to_string[] table with a new name and start using the
newly generated SECINITSID_name symbol in code), and refpolicy could
at that time rename its declaration of that initial SID to reflect its
new purpose and start assigning it a context going
forward. Existing/old policies would map the reclaimed initial SID to
the unlabeled context, so that would be the initial default behavior
until policies are updated. This doesn't depend on the selinux
userspace change; it will work with existing policies and userspace.

2. In 6 months or so we'll have another SELinux userspace release that
will include the libsepol/checkpolicy support for omitting unused
initial SID contexts.

3. At any time after that release, refpolicy can make that release its
minimum build requirement and drop the sid context statements (but not
the sid declarations) for all of the unused initial SIDs except for
fs and sysctl, which must remain for compatibility on policy
reload with old kernels and for compatibility with kernels that were
still using SECINITSID_SYSCTL (< 2.6.39). This doesn't depend on this
kernel commit; it will work with previous kernels as well.

4. After N years for some value of N, refpolicy decides that it no
longer cares about policy reload compatibility for kernels that
predate this kernel commit, and refpolicy drops the fs and sysctl
SID contexts from policy too (but retains the declarations).

5. After M years for some value of M, the kernel decides that it no
longer cares about compatibility with refpolicies that predate step 4
(dropping the fs and sysctl SIDs), and those two SIDs also become
safely reclaimable.  This step is optional and need not ever occur unless
we decide that the need to reclaim those two SIDs outweighs the
compatibility cost.

6. After O years for some value of O, refpolicy decides that it no
longer cares about policy load (not just reload) compatibility for
kernels that predate this kernel commit, and both kernel and refpolicy
can then start adding and using new initial SIDs beyond 27. This does
not depend on the previous change (step 5) and can occur independent
of it.

Fixes: https://github.com/SELinuxProject/selinux-kernel/issues/12
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-27 19:34:24 -05:00
Ondrej Mosnacek e0ac568de1 selinux: reduce the use of hard-coded hash sizes
Instead allocate hash tables with just the right size based on the
actual number of elements (which is almost always known beforehand, we
just need to defer the hashtab allocation to the right time). The only
case when we don't know the size (with the current policy format) is the
new filename transitions hashtable. Here I just left the existing value.

After this patch, the time to load Fedora policy on x86_64 decreases
from 790 ms to 167 ms. If the unconfined module is removed, it decreases
from 750 ms to 122 ms. It is also likely that other operations are going
to be faster, mainly string_to_context_struct() or mls_compute_sid(),
but I didn't try to quantify that.

The memory usage of all hash table arrays increases from ~58 KB to
~163 KB (with Fedora policy on x86_64).

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-27 19:23:20 -05:00
Ondrej Mosnacek c3a276111e selinux: optimize storage of filename transitions
In these rules, each rule with the same (target type, target class,
filename) values is (in practice) always mapped to the same result type.
Therefore, it is much more efficient to group the rules by (ttype,
tclass, filename).

Thus, this patch drops the stype field from the key and changes the
datum to be a linked list of one or more structures that contain a
result type and an ebitmap of source types that map the given target to
the given result type under the given filename. The size of the hash
table is also incremented to 2048 to be more optimal for Fedora policy
(which currently has ~2500 unique (ttype, tclass, filename) tuples,
regardless of whether the 'unconfined' module is enabled).

Not only does this dramtically reduce memory usage when the policy
contains a lot of unconfined domains (ergo a lot of filename based
transitions), but it also slightly reduces memory usage of strongly
confined policies (modeled on Fedora policy with 'unconfined' module
disabled) and significantly reduces lookup times of these rules on
Fedora (roughly matches the performance of the rhashtable conversion
patch [1] posted recently to selinux@vger.kernel.org).

An obvious next step is to change binary policy format to match this
layout, so that disk space is also saved. However, since that requires
more work (including matching userspace changes) and this patch is
already beneficial on its own, I'm posting it separately.

Performance/memory usage comparison:

Kernel           | Policy load | Policy load   | Mem usage | Mem usage     | openbench
                 |             | (-unconfined) |           | (-unconfined) | (createfiles)
-----------------|-------------|---------------|-----------|---------------|--------------
reference        |       1,30s |         0,91s |      90MB |          77MB | 55 us/file
rhashtable patch |       0.98s |         0,85s |      85MB |          75MB | 38 us/file
this patch       |       0,95s |         0,87s |      75MB |          75MB | 40 us/file

(Memory usage is measured after boot. With SELinux disabled the memory
usage was ~60MB on the same system.)

[1] https://lore.kernel.org/selinux/20200116213937.77795-1-dev@lynxeye.de/T/

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-22 11:22:32 -05:00
Ondrej Mosnacek 253050f57c selinux: factor out loop body from filename_trans_read()
It simplifies cleanup in the error path. This will be extra useful in
later patch.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-13 18:08:15 -05:00
Ondrej Mosnacek 89d4d7c88d selinux: generalize evaluate_cond_node()
Both callers iterate the cond_list and call it for each node - turn it
into evaluate_cond_nodes(), which does the iteration for them.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-11 21:50:26 -05:00
Ondrej Mosnacek 8794d78390 selinux: convert cond_expr to array
Since it is fixed-size after allocation and we know the size beforehand,
using a plain old array is simpler and more efficient.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-11 21:48:50 -05:00
Ondrej Mosnacek 2b3a003e15 selinux: convert cond_av_list to array
Since it is fixed-size after allocation and we know the size beforehand,
using a plain old array is simpler and more efficient.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-11 21:42:27 -05:00
Ondrej Mosnacek 60abd3181d selinux: convert cond_list to array
Since it is fixed-size after allocation and we know the size beforehand,
using a plain old array is simpler and more efficient.

While there, also fix signedness of some related variables/parameters.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-11 21:39:41 -05:00
Christian Göttsche 7470d0d13f selinux: allow kernfs symlinks to inherit parent directory context
Currently symlinks on kernel filesystems, like sysfs, are labeled on
creation with the parent filesystem root sid.

Allow symlinks to inherit the parent directory context, so fine-grained
kernfs labeling can be applied to symlinks too and checking contexts
doesn't complain about them.

For backward-compatibility this behavior is contained in a new policy
capability: genfs_seclabel_symlinks

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-10 10:49:01 -05:00
Ondrej Mosnacek 06c2efe2cf selinux: simplify evaluate_cond_node()
It never fails, so it can just return void.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-10 10:49:01 -05:00
Ondrej Mosnacek 4b36cb773a selinux: move status variables out of selinux_ss
It fits more naturally in selinux_state, since it reflects also global
state (the enforcing and policyload fields).

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-10 10:49:01 -05:00
Ondrej Mosnacek 39a706fbcf selinux: fix sidtab string cache locking
Avoiding taking a lock in an IRQ context is not enough to prevent
deadlocks, as discovered by syzbot:

===
WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
5.5.0-syzkaller #0 Not tainted
-----------------------------------------------------
syz-executor.0/8927 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire:
ffff888027c94098 (&(&s->cache_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline]
ffff888027c94098 (&(&s->cache_lock)->rlock){+.+.}, at: sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533

and this task is already holding:
ffffffff898639b0 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline]
ffffffff898639b0 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91
which would create a new lock dependency:
 (&(&nf_conntrack_locks[i])->rlock){+.-.} -> (&(&s->cache_lock)->rlock){+.+.}

but this new dependency connects a SOFTIRQ-irq-safe lock:
 (&(&nf_conntrack_locks[i])->rlock){+.-.}

[...]

other info that might help us debug this:

 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&(&s->cache_lock)->rlock);
                               local_irq_disable();
                               lock(&(&nf_conntrack_locks[i])->rlock);
                               lock(&(&s->cache_lock)->rlock);
  <Interrupt>
    lock(&(&nf_conntrack_locks[i])->rlock);

 *** DEADLOCK ***
[...]
===

Fix this by simply locking with irqsave/irqrestore and stop giving up on
!in_task(). It makes the locking a bit slower, but it shouldn't make a
big difference in real workloads. Under the scenario from [1] (only
cache hits) it only increased the runtime overhead from the
security_secid_to_secctx() function from ~2% to ~3% (it was ~5-65%
before introducing the cache).

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1733259

Fixes: d97bd23c2d ("selinux: cache the SID -> context string translation")
Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-02-05 18:31:10 -05:00
Ondrej Mosnacek dd89b9d9f3 selinux: do not allocate ancillary buffer on first load
In security_load_policy(), we can defer allocating the newpolicydb
ancillary array to after checking state->initialized, thereby avoiding
the pointless allocation when loading policy the first time.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: merged portions by hand]
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-01-16 16:05:25 -05:00
Ondrej Mosnacek ae3d8c2e27 selinux: fix wrong buffer types in policydb.c
Two places used u32 where there should have been __le32.

Fixes sparse warnings:
  CHECK   [...]/security/selinux/ss/services.c
[...]/security/selinux/ss/policydb.c:2669:16: warning: incorrect type in assignment (different base types)
[...]/security/selinux/ss/policydb.c:2669:16:    expected unsigned int
[...]/security/selinux/ss/policydb.c:2669:16:    got restricted __le32 [usertype]
[...]/security/selinux/ss/policydb.c:2674:24: warning: incorrect type in assignment (different base types)
[...]/security/selinux/ss/policydb.c:2674:24:    expected unsigned int
[...]/security/selinux/ss/policydb.c:2674:24:    got restricted __le32 [usertype]
[...]/security/selinux/ss/policydb.c:2675:24: warning: incorrect type in assignment (different base types)
[...]/security/selinux/ss/policydb.c:2675:24:    expected unsigned int
[...]/security/selinux/ss/policydb.c:2675:24:    got restricted __le32 [usertype]
[...]/security/selinux/ss/policydb.c:2676:24: warning: incorrect type in assignment (different base types)
[...]/security/selinux/ss/policydb.c:2676:24:    expected unsigned int
[...]/security/selinux/ss/policydb.c:2676:24:    got restricted __le32 [usertype]
[...]/security/selinux/ss/policydb.c:2681:32: warning: incorrect type in assignment (different base types)
[...]/security/selinux/ss/policydb.c:2681:32:    expected unsigned int
[...]/security/selinux/ss/policydb.c:2681:32:    got restricted __le32 [usertype]
[...]/security/selinux/ss/policydb.c:2701:16: warning: incorrect type in assignment (different base types)
[...]/security/selinux/ss/policydb.c:2701:16:    expected unsigned int
[...]/security/selinux/ss/policydb.c:2701:16:    got restricted __le32 [usertype]
[...]/security/selinux/ss/policydb.c:2706:24: warning: incorrect type in assignment (different base types)
[...]/security/selinux/ss/policydb.c:2706:24:    expected unsigned int
[...]/security/selinux/ss/policydb.c:2706:24:    got restricted __le32 [usertype]
[...]/security/selinux/ss/policydb.c:2707:24: warning: incorrect type in assignment (different base types)
[...]/security/selinux/ss/policydb.c:2707:24:    expected unsigned int
[...]/security/selinux/ss/policydb.c:2707:24:    got restricted __le32 [usertype]

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-01-16 14:31:05 -05:00
Ondrej Mosnacek 65cddd5098 selinux: treat atomic flags more carefully
The disabled/enforcing/initialized flags are all accessed concurrently
by threads so use the appropriate accessors that ensure atomicity and
document that it is expected.

Use smp_load/acquire...() helpers (with memory barriers) for the
initialized flag, since it gates access to the rest of the state
structures.

Note that the disabled flag is currently not used for anything other
than avoiding double disable, but it will be used for bailing out of
hooks once security_delete_hooks() is removed.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2020-01-10 15:19:39 -05:00
YueHaibing f126853402 selinux: remove set but not used variable 'sidtab'
security/selinux/ss/services.c: In function security_port_sid:
security/selinux/ss/services.c:2346:17: warning: variable sidtab set but not used [-Wunused-but-set-variable]
security/selinux/ss/services.c: In function security_ib_endport_sid:
security/selinux/ss/services.c:2435:17: warning: variable sidtab set but not used [-Wunused-but-set-variable]
security/selinux/ss/services.c: In function security_netif_sid:
security/selinux/ss/services.c:2480:17: warning: variable sidtab set but not used [-Wunused-but-set-variable]
security/selinux/ss/services.c: In function security_fs_use:
security/selinux/ss/services.c:2831:17: warning: variable sidtab set but not used [-Wunused-but-set-variable]

Since commit 66f8e2f03c ("selinux: sidtab reverse lookup hash table")
'sidtab' is not used any more, so remove it.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-12-24 14:34:01 -05:00
Paul Moore 15b590a81f selinux: ensure the policy has been loaded before reading the sidtab stats
Check to make sure we have loaded a policy before we query the
sidtab's hash stats.  Failure to do so could result in a kernel
panic/oops due to a dereferenced NULL pointer.

Fixes: 66f8e2f03c ("selinux: sidtab reverse lookup hash table")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-12-23 16:38:36 -05:00
Stephen Smalley 5c108d4e18 selinux: randomize layout of key structures
Randomize the layout of key selinux data structures.
Initially this is applied to the selinux_state, selinux_ss,
policydb, and task_security_struct data structures.

NB To test/use this mechanism, one must install the
necessary build-time dependencies, e.g. gcc-plugin-devel on Fedora,
and enable CONFIG_GCC_PLUGIN_RANDSTRUCT in the kernel configuration.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: Kees Cook <keescook@chromium.org>
[PM: double semi-colon fixed]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-12-18 21:26:06 -05:00
Ondrej Mosnacek d97bd23c2d selinux: cache the SID -> context string translation
Translating a context struct to string can be quite slow, especially if
the context has a lot of category bits set. This can cause quite
noticeable performance impact in situations where the translation needs
to be done repeatedly. A common example is a UNIX datagram socket with
the SO_PASSSEC option enabled, which is used e.g. by systemd-journald
when receiving log messages via datagram socket. This scenario can be
reproduced with:

    cat /dev/urandom | base64 | logger &
    timeout 30s perf record -p $(pidof systemd-journald) -a -g
    kill %1
    perf report -g none --pretty raw | grep security_secid_to_secctx

Before the caching introduced by this patch, computing the context
string (security_secid_to_secctx() function) takes up ~65% of
systemd-journald's CPU time (assuming a context with 1024 categories
set and Fedora x86_64 release kernel configs). After this patch
(assuming near-perfect cache hit ratio) this overhead is reduced to just
~2%.

This patch addresses the issue by caching a certain number (compile-time
configurable) of recently used context strings to speed up repeated
translations of the same context, while using only a small amount of
memory.

The cache is integrated into the existing sidtab table by adding a field
to each entry, which when not NULL contains an RCU-protected pointer to
a cache entry containing the cached string. The cache entries are kept
in a linked list sorted according to how recently they were used. On a
cache miss when the cache is full, the least recently used entry is
removed to make space for the new entry.

The patch migrates security_sid_to_context_core() to use the cache (also
a few other functions where it was possible without too much fuss, but
these mostly use the translation for logging in case of error, which is
rare).

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1733259
Cc: Michal Sekletar <msekleta@redhat.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Tested-by: Stephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
[PM: lots of merge fixups due to collisions with other sidtab patches]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-12-09 16:14:51 -05:00
Jeff Vander Stoep 66f8e2f03c selinux: sidtab reverse lookup hash table
This replaces the reverse table lookup and reverse cache with a
hashtable which improves cache-miss reverse-lookup times from
O(n) to O(1)* and maintains the same performance as a reverse
cache hit.

This reduces the time needed to add a new sidtab entry from ~500us
to 5us on a Pixel 3 when there are ~10,000 sidtab entries.

The implementation uses the kernel's generic hashtable API,
It uses the context's string represtation as the hash source,
and the kernels generic string hashing algorithm full_name_hash()
to reduce the string to a 32 bit value.

This change also maintains the improvement introduced in
commit ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve
performance") which removed the need to keep the current sidtab
locked during policy reload. It does however introduce periodic
locking of the target sidtab while converting the hashtable. Sidtab
entries are never modified or removed, so the context struct stored
in the sid_to_context tree can also be used for the context_to_sid
hashtable to reduce memory usage.

This bug was reported by:
- On the selinux bug tracker.
  BUG: kernel softlockup due to too many SIDs/contexts #37
  https://github.com/SELinuxProject/selinux-kernel/issues/37
- Jovana Knezevic on Android's bugtracker.
  Bug: 140252993
  "During multi-user performance testing, we create and remove users
  many times. selinux_android_restorecon_pkgdir goes from 1ms to over
  20ms after about 200 user creations and removals. Accumulated over
  ~280 packages, that adds a significant time to user creation,
  making perf benchmarks unreliable."

* Hashtable lookup is only O(1) when n < the number of buckets.

Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Reported-by: Stephen Smalley <sds@tycho.nsa.gov>
Reported-by: Jovana Knezevic <jovanak@google.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Tested-by: Stephen Smalley <sds@tycho.nsa.gov>
[PM: subj tweak, removed changelog from patch description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-12-09 16:14:51 -05:00
Linus Torvalds ba75082efc selinux/stable-5.5 PR 20191126
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Merge tag 'selinux-pr-20191126' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "Only three SELinux patches for v5.5:

   - Remove the size limit on SELinux policies, the limitation was a
     lingering vestige and no longer necessary.

   - Allow file labeling before the policy is loaded. This should ease
     some of the burden when the policy is initially loaded (no need to
     relabel files), but it should also help enable some new system
     concepts which dynamically create the root filesystem in the
     initrd.

   - Add support for the "greatest lower bound" policy construct which
     is defined as the intersection of the MLS range of two SELinux
     labels"

* tag 'selinux-pr-20191126' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: default_range glblub implementation
  selinux: allow labeling before policy is loaded
  selinux: remove load size limit
2019-11-30 16:55:37 -08:00
Linus Torvalds 2ef459167a selinux/stable-5.4 PR 20191007
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Merge tag 'selinux-pr-20191007' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinuxfix from Paul Moore:
 "One patch to ensure we don't copy bad memory up into userspace"

* tag 'selinux-pr-20191007' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: fix context string corruption in convert_context()
2019-10-08 10:51:37 -07:00
Joshua Brindle 42345b68c2 selinux: default_range glblub implementation
A policy developer can now specify glblub as a default_range default and
the computed transition will be the intersection of the mls range of
the two contexts.

The glb (greatest lower bound) lub (lowest upper bound) of a range is calculated
as the greater of the low sensitivities and the lower of the high sensitivities
and the and of each category bitmap.

This can be used by MLS solution developers to compute a context that satisfies,
for example, the range of a network interface and the range of a user logging in.

Some examples are:

User Permitted Range | Network Device Label | Computed Label
---------------------|----------------------|----------------
s0-s1:c0.c12         | s0                   | s0
s0-s1:c0.c12         | s0-s1:c0.c1023       | s0-s1:c0.c12
s0-s4:c0.c512        | s1-s1:c0.c1023       | s1-s1:c0.c512
s0-s15:c0,c2         | s4-s6:c0.c128        | s4-s6:c0,c2
s0-s4                | s2-s6                | s2-s4
s0-s4                | s5-s8                | INVALID
s5-s8                | s0-s4                | INVALID

Signed-off-by: Joshua Brindle <joshua.brindle@crunchydata.com>
[PM: subject lines and checkpatch.pl fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-10-07 19:01:35 -04:00
Ondrej Mosnacek 2a5243937c selinux: fix context string corruption in convert_context()
string_to_context_struct() may garble the context string, so we need to
copy back the contents again from the old context struct to avoid
storing the corrupted context.

Since string_to_context_struct() tokenizes (and therefore truncates) the
context string and we are later potentially copying it with kstrdup(),
this may eventually cause pieces of uninitialized kernel memory to be
disclosed to userspace (when copying to userspace based on the stored
length and not the null character).

How to reproduce on Fedora and similar:
    # dnf install -y memcached
    # systemctl start memcached
    # semodule -d memcached
    # load_policy
    # load_policy
    # systemctl stop memcached
    # ausearch -m AVC
    type=AVC msg=audit(1570090572.648:313): avc:  denied  { signal } for  pid=1 comm="systemd" scontext=system_u:system_r:init_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=process permissive=0 trawcon=73797374656D5F75007400000000000070BE6E847296FFFF726F6D000096FFFF76

Cc: stable@vger.kernel.org
Reported-by: Milos Malik <mmalik@redhat.com>
Fixes: ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve performance")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-10-03 14:13:36 -04:00
Linus Torvalds 5825a95fe9 selinux/stable-5.4 PR 20190917
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Merge tag 'selinux-pr-20190917' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:

 - Add LSM hooks, and SELinux access control hooks, for dnotify,
   fanotify, and inotify watches. This has been discussed with both the
   LSM and fs/notify folks and everybody is good with these new hooks.

 - The LSM stacking changes missed a few calls to current_security() in
   the SELinux code; we fix those and remove current_security() for
   good.

 - Improve our network object labeling cache so that we always return
   the object's label, even when under memory pressure. Previously we
   would return an error if we couldn't allocate a new cache entry, now
   we always return the label even if we can't create a new cache entry
   for it.

 - Convert the sidtab atomic_t counter to a normal u32 with
   READ/WRITE_ONCE() and memory barrier protection.

 - A few patches to policydb.c to clean things up (remove forward
   declarations, long lines, bad variable names, etc)

* tag 'selinux-pr-20190917' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  lsm: remove current_security()
  selinux: fix residual uses of current_security() for the SELinux blob
  selinux: avoid atomic_t usage in sidtab
  fanotify, inotify, dnotify, security: add security hook for fs notifications
  selinux: always return a secid from the network caches if we find one
  selinux: policydb - rename type_val_to_struct_array
  selinux: policydb - fix some checkpatch.pl warnings
  selinux: shuffle around policydb.c to get rid of forward declarations
2019-09-23 11:21:04 -07:00
Ondrej Mosnacek 116f21bb96 selinux: avoid atomic_t usage in sidtab
As noted in Documentation/atomic_t.txt, if we don't need the RMW atomic
operations, we should only use READ_ONCE()/WRITE_ONCE() +
smp_rmb()/smp_wmb() where necessary (or the combined variants
smp_load_acquire()/smp_store_release()).

This patch converts the sidtab code to use regular u32 for the counter
and reverse lookup cache and use the appropriate operations instead of
atomic_get()/atomic_set(). Note that when reading/updating the reverse
lookup cache we don't need memory barriers as it doesn't need to be
consistent or accurate. We can now also replace some atomic ops with
regular loads (when under spinlock) and stores (for conversion target
fields that are always accessed under the master table's spinlock).

We can now also bump SIDTAB_MAX to U32_MAX as we can use the full u32
range again.

Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Jann Horn <jannh@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-08-27 13:26:13 -04:00
Ondrej Mosnacek f07ea1d4ed selinux: policydb - rename type_val_to_struct_array
The name is overly long and inconsistent with the other *_val_to_struct
members. Dropping the "_array" prefix makes the code easier to read and
gets rid of one line over 80 characters warning.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-08-05 16:21:06 -04:00
Ondrej Mosnacek 2492acaf1e selinux: policydb - fix some checkpatch.pl warnings
Fix most of the code style warnings discovered when moving code around.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-08-05 16:17:56 -04:00
Paul Moore 0eb2f29624 selinux: shuffle around policydb.c to get rid of forward declarations
No code changes, but move a lot of the policydb destructors higher up
so we can get rid of a forward declaration.

This patch does expose a few old checkpatch.pl errors, but those will
be dealt with in a separate (set of) patches.

Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-08-05 15:58:57 -04:00
Linus Torvalds 4f1a6ef1df selinux/stable-5.3 PR 20190801
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Merge tag 'selinux-pr-20190801' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux fix from Paul Moore:
 "One more small fix for a potential memory leak in an error path"

* tag 'selinux-pr-20190801' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: fix memory leak in policydb_init()
2019-08-02 18:40:49 -07:00
Ondrej Mosnacek 45385237f6 selinux: fix memory leak in policydb_init()
Since roles_init() adds some entries to the role hash table, we need to
destroy also its keys/values on error, otherwise we get a memory leak in
the error path.

Cc: <stable@vger.kernel.org>
Reported-by: syzbot+fee3a14d4cdf92646287@syzkaller.appspotmail.com
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-07-31 16:51:23 -04:00
Linus Torvalds 40233e7c44 selinux/stable-5.3 PR 20190726
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Merge tag 'selinux-pr-20190726' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux fix from Paul Moore:
 "One small SELinux patch to add some proper bounds/overflow checking
  when adding a new sid/secid"

* tag 'selinux-pr-20190726' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: check sidtab limit before adding a new entry
2019-07-26 19:13:38 -07:00
Ondrej Mosnacek acbc372e61 selinux: check sidtab limit before adding a new entry
We need to error out when trying to add an entry above SIDTAB_MAX in
sidtab_reverse_lookup() to avoid overflow on the odd chance that this
happens.

Cc: stable@vger.kernel.org
Fixes: ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve performance")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-07-24 11:13:34 -04:00
Linus Torvalds 7c0f896348 selinux/stable-5.3 PR 20190702
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Merge tag 'selinux-pr-20190702' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "Like the audit pull request this is a little early due to some
  upcoming vacation plans and uncertain network access while I'm away.
  Also like the audit PR, the list of patches here is pretty minor, the
  highlights include:

   - Explicitly use __le variables to make sure "sparse" can verify
     proper byte endian handling.

   - Remove some BUG_ON()s that are no longer needed.

   - Allow zero-byte writes to the "keycreate" procfs attribute without
     requiring key:create to make it easier for userspace to reset the
     keycreate label.

   - Consistently log the "invalid_context" field as an untrusted string
     in the AUDIT_SELINUX_ERR audit records"

* tag 'selinux-pr-20190702' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: format all invalid context as untrusted
  selinux: fix empty write to keycreate file
  selinux: remove some no-op BUG_ONs
  selinux: provide __le variables explicitly
2019-07-08 18:59:56 -07:00
Richard Guy Briggs ea74a685ad selinux: format all invalid context as untrusted
The userspace tools expect all fields of the same name to be logged
consistently with the same encoding.  Since the invalid_context fields
contain untrusted strings in selinux_inode_setxattr()
and selinux_setprocattr(), encode all instances of this field the same
way as though they were untrusted even though
compute_sid_handle_invalid_context() and security_sid_mls_copy() are
trusted.

Please see github issue
https://github.com/linux-audit/audit-kernel/issues/57

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-07-01 16:29:05 -04:00
Thomas Gleixner d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00
Thomas Gleixner a10e763b87 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation version 2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 135 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081036.435762997@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:37:10 +02:00
Ondrej Mosnacek beee56f354 selinux: remove some no-op BUG_ONs
Since acdf52d97f ("selinux: convert to kvmalloc"), these check whether
an address-of value is NULL, which is pointless.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-05-21 16:23:43 -04:00
Nicholas Mc Guire 8ba1d53739 selinux: provide __le variables explicitly
While the endiannes is being handled properly sparse was unable to verify
this due to type inconsistency. So introduce an additional __le32
respectively _le64 variable to be passed to le32/64_to_cpu() to allow
sparse to verify proper typing. Note that this patch does not change
the generated binary on little-endian systems - on 32bit powerpc it
does change the binary.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-05-21 15:49:21 -04:00
Linus Torvalds f72dae2089 selinux/stable-5.2 PR 20190507
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Merge tag 'selinux-pr-20190507' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "We've got a few SELinux patches for the v5.2 merge window, the
  highlights are below:

   - Add LSM hooks, and the SELinux implementation, for proper labeling
     of kernfs. While we are only including the SELinux implementation
     here, the rest of the LSM folks have given the hooks a thumbs-up.

   - Update the SELinux mdp (Make Dummy Policy) script to actually work
     on a modern system.

   - Disallow userspace to change the LSM credentials via
     /proc/self/attr when the task's credentials are already overridden.

     The change was made in procfs because all the LSM folks agreed this
     was the Right Thing To Do and duplicating it across each LSM was
     going to be annoying"

* tag 'selinux-pr-20190507' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  proc: prevent changes to overridden credentials
  selinux: Check address length before reading address family
  kernfs: fix xattr name handling in LSM helpers
  MAINTAINERS: update SELinux file patterns
  selinux: avoid uninitialized variable warning
  selinux: remove useless assignments
  LSM: lsm_hooks.h - fix missing colon in docstring
  selinux: Make selinux_kernfs_init_security static
  kernfs: initialize security of newly created nodes
  selinux: implement the kernfs_init_security hook
  LSM: add new hook for kernfs node initialization
  kernfs: use simple_xattrs for security attributes
  selinux: try security xattr after genfs for kernfs filesystems
  kernfs: do not alloc iattrs in kernfs_xattr_get
  kernfs: clean up struct kernfs_iattrs
  scripts/selinux: fix build
  selinux: use kernel linux/socket.h for genheaders and mdp
  scripts/selinux: modernize mdp
2019-05-07 18:48:09 -07:00
Ondrej Mosnacek 9e0cfe28fa selinux: remove useless assignments
The code incorrectly assigned directly to the variables instead of the
values they point to. Since the values are already set to NULL/0 at the
beginning of the function, we can simply remove these useless
assignments.

Reported-by: Hariprasad Kelam <hariprasad.kelam@gmail.com>
Fixes: fede148324 ("selinux: log invalid contexts in AVCs")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: removed a bad comment that was causing compiler warnings]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-03-25 10:25:06 -04:00
Ondrej Mosnacek 6a1afffb08 selinux: fix NULL dereference in policydb_destroy()
The conversion to kvmalloc() forgot to account for the possibility that
p->type_attr_map_array might be null in policydb_destroy().

Fix this by destroying its contents only if it is not NULL.

Also make sure ebitmap_init() is called on all entries before
policydb_destroy() can be called. Right now this is a no-op, because
both kvcalloc() and ebitmap_init() just zero out the whole struct, but
let's rather not rely on a specific implementation.

Reported-by: syzbot+a57b2aff60832666fc28@syzkaller.appspotmail.com
Fixes: acdf52d97f ("selinux: convert to kvmalloc")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-03-18 12:19:48 -04:00
Kent Overstreet acdf52d97f selinux: convert to kvmalloc
The flex arrays were being used for constant sized arrays, so there's no
benefit to using flex_arrays over something simpler.

Link: http://lkml.kernel.org/r/20181217131929.11727-4-kent.overstreet@gmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Pravin B Shelar <pshelar@ovn.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-12 10:04:02 -07:00
Linus Torvalds be37f21a08 audit/stable-5.1 PR 20190305
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Merge tag 'audit-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit

Pull audit updates from Paul Moore:
 "A lucky 13 audit patches for v5.1.

  Despite the rather large diffstat, most of the changes are from two
  bug fix patches that move code from one Kconfig option to another.

  Beyond that bit of churn, the remaining changes are largely cleanups
  and bug-fixes as we slowly march towards container auditing. It isn't
  all boring though, we do have a couple of new things: file
  capabilities v3 support, and expanded support for filtering on
  filesystems to solve problems with remote filesystems.

  All changes pass the audit-testsuite.  Please merge for v5.1"

* tag 'audit-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
  audit: mark expected switch fall-through
  audit: hide auditsc_get_stamp and audit_serial prototypes
  audit: join tty records to their syscall
  audit: remove audit_context when CONFIG_ AUDIT and not AUDITSYSCALL
  audit: remove unused actx param from audit_rule_match
  audit: ignore fcaps on umount
  audit: clean up AUDITSYSCALL prototypes and stubs
  audit: more filter PATH records keyed on filesystem magic
  audit: add support for fcaps v3
  audit: move loginuid and sessionid from CONFIG_AUDITSYSCALL to CONFIG_AUDIT
  audit: add syscall information to CONFIG_CHANGE records
  audit: hand taken context to audit_kill_trees for syscall logging
  audit: give a clue what CONFIG_CHANGE op was involved
2019-03-07 12:20:11 -08:00
Linus Torvalds 3ac96c30cc selinux/stable-5.1 PR 20190305
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Merge tag 'selinux-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull SELinux updates from Paul Moore:
 "Nine SELinux patches for v5.1, all bug fixes.

  As far as I'm concerned, nothing really jumps out as risky or special
  to me, but each commit has a decent description so you can judge for
  yourself. As usual, everything passes the selinux-testsuite; please
  merge for v5.1"

* tag 'selinux-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: fix avc audit messages
  selinux: replace BUG_ONs with WARN_ONs in avc.c
  selinux: log invalid contexts in AVCs
  selinux: replace some BUG_ON()s with a WARN_ON()
  selinux: inline some AVC functions used only once
  selinux: do not override context on context mounts
  selinux: never allow relabeling on context mounts
  selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link
  selinux: avoid silent denials in permissive mode under RCU walk
2019-03-07 12:12:45 -08:00
Richard Guy Briggs 90462a5bd3 audit: remove unused actx param from audit_rule_match
The audit_rule_match() struct audit_context *actx parameter is not used
by any in-tree consumers (selinux, apparmour, integrity, smack).

The audit context is an internal audit structure that should only be
accessed by audit accessor functions.

It was part of commit 03d37d25e0 ("LSM/Audit: Introduce generic
Audit LSM hooks") but appears to have never been used.

Remove it.

Please see the github issue
https://github.com/linux-audit/audit-kernel/issues/107

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: fixed the referenced commit title]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-31 23:00:15 -05:00
Ondrej Mosnacek fede148324 selinux: log invalid contexts in AVCs
In case a file has an invalid context set, in an AVC record generated
upon access to such file, the target context is always reported as
unlabeled. This patch adds new optional fields to the AVC record
(srawcon and trawcon) that report the actual context string if it
differs from the one reported in scontext/tcontext. This is useful for
diagnosing SELinux denials involving invalid contexts.

To trigger an AVC that illustrates this situation:

    # setenforce 0
    # touch /tmp/testfile
    # setfattr -n security.selinux -v system_u:object_r:banana_t:s0 /tmp/testfile
    # runcon system_u:system_r:sshd_t:s0 cat /tmp/testfile

AVC before:

type=AVC msg=audit(1547801083.248:11): avc:  denied  { open } for  pid=1149 comm="cat" path="/tmp/testfile" dev="tmpfs" ino=6608 scontext=system_u:system_r:sshd_t:s0 tcontext=system_u:object_r:unlabeled_t:s15:c0.c1023 tclass=file permissive=1

AVC after:

type=AVC msg=audit(1547801083.248:11): avc:  denied  { open } for  pid=1149 comm="cat" path="/tmp/testfile" dev="tmpfs" ino=6608 scontext=system_u:system_r:sshd_t:s0 tcontext=system_u:object_r:unlabeled_t:s15:c0.c1023 tclass=file permissive=1 trawcon=system_u:object_r:banana_t:s0

Note that it is also possible to encounter this situation with the
'scontext' field - e.g. when a new policy is loaded while a process is
running, whose context is not valid in the new policy.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1135683

Cc: Daniel Walsh <dwalsh@redhat.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-25 17:31:14 -05:00