This change has two goals:
 - delay the setting of 'smack_enabled' until
   it will be really effective
 - ensure that smackfs is valid only if 'smack_enabled'
   is set (it is already the case in smack_netfilter.c)
Signed-off-by: NJosé Bollo <jose.bollo@iot.bzh>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>

Fixes the following sparse warning:

 security/smack/smack_lsm.c:55:1: warning: symbol 'smk_ipv6_port_list'
 was not declared. Should it be static?
Signed-off-by: NGeliang Tang <geliangtang@163.com>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>

'commit e774ad68 ("smack: pass error code through pointers")'
made this function return proper error codes instead of NULL. Reflect that.

This is a fix for a NULL dereference introduced in
'commit 21abb1ec ("Smack: IPv6 host labeling")'

echo "$SOME_IPV6_ADDR \"test" > /smack/ipv6host
  (this should return EINVAL, it doesn't)
cat /smack/ipv6host
  (derefences 0x000a)
Signed-off-by: NLukasz Pawelczyk <l.pawelczyk@samsung.com>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>

The changes for mounting binary filesystems was allied
improperly, with the list of tokens being in an ifdef that
it shouldn't have been. Fix that, and a couple style issues
that were bothering me.
Reported-by: NJim Davis <jim.epost@gmail.com>
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>

Adds an ignore case for kernel tasks,
so that they can access all resources.

Since kernel worker threads are spawned with
floor label, they are severely restricted by
Smack policy. It is not an issue without onlycap,
as these processes also run with root,
so CAP_MAC_OVERRIDE kicks in. But with onlycap
turned on, there is no way to change the label
for these processes.
Signed-off-by: NRoman Kubiak <r.kubiak@samsung.com>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>

The kbuild test robot reported a couple of these,
and the third showed up by inspection. Making the
symbols static is proper.
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>

IPv6 appears to be (finally) coming of age with the
influx of autonomous devices. In support of this, add
the ability to associate a Smack label with IPv6 addresses.

This patch also cleans up some of the conditional
compilation associated with the introduction of
secmark processing. It's now more obvious which bit
of code goes with which feature.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>

security/smack/smackfs.c:2251:1-4: WARNING: end returns can be
simpified and declaration on line 2250 can be dropped

 Simplify a trivial if-return sequence.  Possibly combine with a
 preceding function call.

Generated by: scripts/coccinelle/misc/simple_return.cocci
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>

Add support for setting smack mount labels(using smackfsdef, smackfsroot,
smackfshat, smackfsfloor, smackfstransmute) for filesystems with binary
mount data like NFS.

To achieve this, implement sb_parse_opts_str and sb_set_mnt_opts security
operations in smack LSM similar to SELinux.
Signed-off-by: NVivek Trivedi <t.vivek@samsung.com>
Signed-off-by: NAmit Sahrawat <a.sahrawat@samsung.com>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>

This allows for better documentation in the code and
it allows for a simpler and fully correct version of
fs_fully_visible to be written.

The mount points converted and their filesystems are:
/sys/hypervisor/s390/       s390_hypfs
/sys/kernel/config/         configfs
/sys/kernel/debug/          debugfs
/sys/firmware/efi/efivars/  efivarfs
/sys/fs/fuse/connections/   fusectl
/sys/fs/pstore/             pstore
/sys/kernel/tracing/        tracefs
/sys/fs/cgroup/             cgroup
/sys/kernel/security/       securityfs
/sys/fs/selinux/            selinuxfs
/sys/fs/smackfs/            smackfs

Cc: stable@vger.kernel.org
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

This code used to rely on the fact that kfree(NULL) was a no-op, but
then we changed smk_parse_smack() to return error pointers on failure
instead of NULL.  Calling kfree() on an error pointer will oops.

I have re-arranged things a bit so that we only free things if they
have been allocated.

Fixes: e774ad68 ('smack: pass error code through pointers')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>

Smack onlycap allows limiting of CAP_MAC_ADMIN and CAP_MAC_OVERRIDE to
processes running with the configured label. But having single privileged
label is not enough in some real use cases. On a complex system like Tizen,
there maybe few programs that need to configure Smack policy in run-time
and running them all with a single label is not always practical.
This patch extends onlycap feature for multiple labels. They are configured
in the same smackfs "onlycap" interface, separated by spaces.
Signed-off-by: NRafal Krypa <r.krypa@samsung.com>

Use proper RCU functions and read locking in smackfs seq_operations.

Smack gets away with not using proper RCU functions in smackfs, because
it never removes entries from these lists. But now one list will be
needed (with interface in smackfs) that will have both elements added and
removed to it.
This change will also help any future changes implementing removal of
unneeded entries from other Smack lists.

The patch also fixes handling of pos argument in smk_seq_start and
smk_seq_next. This fixes a bug in case when smackfs is read with a small
buffer:

Kernel panic - not syncing: Kernel mode fault at addr 0xfa0000011b
CPU: 0 PID: 1292 Comm: dd Not tainted 4.1.0-rc1-00012-g98179b8 #13
Stack:
 00000003 0000000d 7ff39e48 7f69fd00
 7ff39ce0 601ae4b0 7ff39d50 600e587b
 00000010 6039f690 7f69fd40 00612003
Call Trace:
 [<601ae4b0>] load2_seq_show+0x19/0x1d
 [<600e587b>] seq_read+0x168/0x331
 [<600c5943>] __vfs_read+0x21/0x101
 [<601a595e>] ? security_file_permission+0xf8/0x105
 [<600c5ec6>] ? rw_verify_area+0x86/0xe2
 [<600c5fc3>] vfs_read+0xa1/0x14c
 [<600c68e2>] SyS_read+0x57/0xa0
 [<6001da60>] handle_syscall+0x60/0x80
 [<6003087d>] userspace+0x442/0x548
 [<6001aa77>] ? interrupt_end+0x0/0x80
 [<6001daae>] ? copy_chunk_to_user+0x0/0x2b
 [<6002cb6b>] ? save_registers+0x1f/0x39
 [<60032ef7>] ? arch_prctl+0xf5/0x170
 [<6001a92d>] fork_handler+0x85/0x87
Signed-off-by: NRafal Krypa <r.krypa@samsung.com>

This patch makes the following functions to use ERR_PTR() and related
macros to pass the appropriate error code through returned pointers:

smk_parse_smack()
smk_import_entry()
smk_fetch()

It also makes all the other functions that use them to handle the
error cases properly. This ways correct error codes from places
where they happened can be propagated to the user space if necessary.

Doing this it fixes a bug in onlycap and unconfined files
handling. Previously their content was cleared on any error from
smk_import_entry/smk_parse_smack, be it EINVAL (as originally intended)
or ENOMEM. Right now it only reacts on EINVAL passing other codes
properly to userspace.

Comments have been updated accordingly.
Signed-off-by: NLukasz Pawelczyk <l.pawelczyk@samsung.com>

The dmabuf fd can be shared between processes via unix domain
socket. The file of dmabuf fd is came from anon_inode. The inode
has no set and get xattr operations, so it can not be shared
between processes with smack. This patch fixes just to ignore
private inode including anon_inode for smack_file_receive.
Signed-off-by: NSeung-Woo Kim <sw0312.kim@samsung.com>

Instead of using a vector of security operations
with explicit, special case stacking of the capability
and yama hooks use lists of hooks with capability and
yama hooks included as appropriate.

The security_operations structure is no longer required.
Instead, there is a union of the function pointers that
allows all the hooks lists to use a common mechanism for
list management while retaining typing. Each module
supplies an array describing the hooks it provides instead
of a sparsely populated security_operations structure.
The description includes the element that gets put on
the hook list, avoiding the issues surrounding individual
element allocation.

The method for registering security modules is changed to
reflect the information available. The method for removing
a module, currently only used by SELinux, has also changed.
It should be generic now, however if there are potential
race conditions based on ordering of hook removal that needs
to be addressed by the calling module.

The security hooks are called from the lists and the first
failure is returned.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Acked-by: NJohn Johansen <john.johansen@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NPaul Moore <paul@paul-moore.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Add a list header for each security hook. They aren't used until
later in the patch series. They are grouped together in a structure
so that there doesn't need to be an external address for each.

Macro-ize the initialization of the security_operations
for each security module in anticipation of changing out
the security_operations structure.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Acked-by: NJohn Johansen <john.johansen@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NPaul Moore <paul@paul-moore.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

The security.h header file serves two purposes,
interfaces for users of the security modules and
interfaces for security modules. Users of the
security modules don't need to know about what's
in the security_operations structure, so pull it
out into it's own header, lsm_hooks.h
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Acked-by: NJohn Johansen <john.johansen@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NPaul Moore <paul@paul-moore.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

... except where that code acts as a filesystem driver, rather than
working with dentries given to it.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

most of the ->d_inode uses there refer to the same inode IO would
go to, i.e. d_backing_inode()
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Pass the nf_hook_state all the way down into the hook
functions themselves.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In commit 00f84f3f ("Smack: Make the
syslog control configurable") this mutex was added, but the rest of
the final commit never actually made use of it, resulting in:

 In file included from include/linux/mutex.h:29:0,
                  from include/linux/notifier.h:13,
                  from include/linux/memory_hotplug.h:6,
                  from include/linux/mmzone.h:821,
                  from include/linux/gfp.h:5,
                  from include/linux/slab.h:14,
                  from include/linux/security.h:27,
                  from security/smack/smackfs.c:21:
 security/smack/smackfs.c:63:21: warning: ‘smack_syslog_lock’ defined but not used [-Wunused-variable]
  static DEFINE_MUTEX(smack_syslog_lock);
                      ^

A git grep shows no other instances/references to smack_syslog_lock.
Delete it, assuming that the mutex addition was just a leftover from
an earlier work in progress version of the change.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

I have vehemently opposed adding a "permissive" mode to Smack
for the simple reasons that it would be subject to massive abuse
and that developers refuse to turn it off come product release.
I still believe that this is true, and still refuse to add a
general "permissive mode". So don't ask again.

Bumjin Im suggested an approach that addresses most of the concerns,
and I have implemented it here. I still believe that we'd be better
off without this sort of thing, but it looks like this minimizes the
abuse potential.

Firstly, you have to configure Smack Bringup Mode. That allows
for "release" software to be ammune from abuse. Second, only one
label gets to be "permissive" at a time. You can use it for
debugging, but that's about it.

A label written to smackfs/unconfined is treated specially.
If either the subject or object label of an access check
matches the "unconfined" label, and the access would not
have been allowed otherwise an audit record and a console
message are generated. The audit record "request" string is
marked with either "(US)" or "(UO)", to indicate that the
request was granted because of an unconfined label. The
fact that an inode was accessed by an unconfined label is
remembered, and subsequent accesses to that "impure"
object are noted in the log. The impurity is not stored in
the filesystem, so a file mislabled as a side effect of
using an unconfined label may still cause concern after
a reboot.

So, it's there, it's dangerous, but so many application
developers seem incapable of living without it I have
given in. I've tried to make it as safe as I can, but
in the end it's still a chain saw.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>

With this commit, the LSM Smack implements the LSM
side part of the system call keyctl with the action
code KEYCTL_GET_SECURITY.

It is now possible to get the context of, for example,
the user session key using the command "keyctl security @s".

The original patch has been modified for merge.
Signed-off-by: NJosé Bollo <jose.bollo@open.eurogiciel.org>
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>

This change fixes the bug associated with sockets owned by kernel threads. These
sockets, created usually by network devices' drivers tasks, received smk_in
label from the task that created them - the "floor" label in the most cases. The
result was that they were not able to receive data packets because of missing
smack rules. The main reason of the access deny is that the socket smk_in label
is placed as the object during smk check, kernel thread's capabilities are
omitted.
Signed-off-by: NMarcin Lis <m.lis@samsung.com>

Use d_is_positive() rather than testing dentry->d_inode in Smack to get rid of
direct references to d_inode outside of the VFS.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If the secmark is available us it on connection as
well as packet delivery.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>

On 1/23/2015 8:20 AM, Jim Davis wrote:
> Building with the attached random configuration file,
>
> security/smack/smack_netfilter.c: In function ‘smack_ipv4_output’:
> security/smack/smack_netfilter.c:55:6: error: ‘struct sk_buff’ has no
> member named ‘secmark’
>    skb->secmark = skp->smk_secid;
>       ^
> make[2]: *** [security/smack/smack_netfilter.o] Error 1

The existing Makefile used the wrong configuration option to
determine if smack_netfilter should be built. This sets it right.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>

We hit use after free on dereferncing pointer to task_smack struct in
smk_of_task() called from smack_task_to_inode().

task_security() macro uses task_cred_xxx() to get pointer to the task_smack.
task_cred_xxx() could be used only for non-pointer members of task's
credentials. It cannot be used for pointer members since what they point
to may disapper after dropping RCU read lock.

Mainly task_security() used this way:
	smk_of_task(task_security(p))

Intead of this introduce function smk_of_task_struct() which
takes task_struct as argument and returns pointer to smk_known struct
and do this under RCU read lock.
Bogus task_security() macro is not used anymore, so remove it.

KASan's report for this:

	AddressSanitizer: use after free in smack_task_to_inode+0x50/0x70 at addr c4635600
	=============================================================================
	BUG kmalloc-64 (Tainted: PO): kasan error
	-----------------------------------------------------------------------------

	Disabling lock debugging due to kernel taint
	INFO: Allocated in new_task_smack+0x44/0xd8 age=39 cpu=0 pid=1866
		kmem_cache_alloc_trace+0x88/0x1bc
		new_task_smack+0x44/0xd8
		smack_cred_prepare+0x48/0x21c
		security_prepare_creds+0x44/0x4c
		prepare_creds+0xdc/0x110
		smack_setprocattr+0x104/0x150
		security_setprocattr+0x4c/0x54
		proc_pid_attr_write+0x12c/0x194
		vfs_write+0x1b0/0x370
		SyS_write+0x5c/0x94
		ret_fast_syscall+0x0/0x48
	INFO: Freed in smack_cred_free+0xc4/0xd0 age=27 cpu=0 pid=1564
		kfree+0x270/0x290
		smack_cred_free+0xc4/0xd0
		security_cred_free+0x34/0x3c
		put_cred_rcu+0x58/0xcc
		rcu_process_callbacks+0x738/0x998
		__do_softirq+0x264/0x4cc
		do_softirq+0x94/0xf4
		irq_exit+0xbc/0x120
		handle_IRQ+0x104/0x134
		gic_handle_irq+0x70/0xac
		__irq_svc+0x44/0x78
		_raw_spin_unlock+0x18/0x48
		sync_inodes_sb+0x17c/0x1d8
		sync_filesystem+0xac/0xfc
		vdfs_file_fsync+0x90/0xc0
		vfs_fsync_range+0x74/0x7c
	INFO: Slab 0xd3b23f50 objects=32 used=31 fp=0xc4635600 flags=0x4080
	INFO: Object 0xc4635600 @offset=5632 fp=0x  (null)

	Bytes b4 c46355f0: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  ZZZZZZZZZZZZZZZZ
	Object c4635600: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
	Object c4635610: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
	Object c4635620: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
	Object c4635630: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5  kkkkkkkkkkkkkkk.
	Redzone c4635640: bb bb bb bb                                      ....
	Padding c46356e8: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a  ZZZZZZZZZZZZZZZZ
	Padding c46356f8: 5a 5a 5a 5a 5a 5a 5a 5a                          ZZZZZZZZ
	CPU: 5 PID: 834 Comm: launchpad_prelo Tainted: PBO 3.10.30 #1
	Backtrace:
	[<c00233a4>] (dump_backtrace+0x0/0x158) from [<c0023dec>] (show_stack+0x20/0x24)
	 r7:c4634010 r6:d3b23f50 r5:c4635600 r4:d1002140
	[<c0023dcc>] (show_stack+0x0/0x24) from [<c06d6d7c>] (dump_stack+0x20/0x28)
	[<c06d6d5c>] (dump_stack+0x0/0x28) from [<c01c1d50>] (print_trailer+0x124/0x144)
	[<c01c1c2c>] (print_trailer+0x0/0x144) from [<c01c1e88>] (object_err+0x3c/0x44)
	 r7:c4635600 r6:d1002140 r5:d3b23f50 r4:c4635600
	[<c01c1e4c>] (object_err+0x0/0x44) from [<c01cac18>] (kasan_report_error+0x2b8/0x538)
	 r6:d1002140 r5:d3b23f50 r4:c6429cf8 r3:c09e1aa7
	[<c01ca960>] (kasan_report_error+0x0/0x538) from [<c01c9430>] (__asan_load4+0xd4/0xf8)
	[<c01c935c>] (__asan_load4+0x0/0xf8) from [<c031e168>] (smack_task_to_inode+0x50/0x70)
	 r5:c4635600 r4:ca9da000
	[<c031e118>] (smack_task_to_inode+0x0/0x70) from [<c031af64>] (security_task_to_inode+0x3c/0x44)
	 r5:cca25e80 r4:c0ba9780
	[<c031af28>] (security_task_to_inode+0x0/0x44) from [<c023d614>] (pid_revalidate+0x124/0x178)
	 r6:00000000 r5:cca25e80 r4:cbabe3c0 r3:00008124
	[<c023d4f0>] (pid_revalidate+0x0/0x178) from [<c01db98c>] (lookup_fast+0x35c/0x43y4)
	 r9:c6429efc r8:00000101 r7:c079d940 r6:c6429e90 r5:c6429ed8 r4:c83c4148
	[<c01db630>] (lookup_fast+0x0/0x434) from [<c01deec8>] (do_last.isra.24+0x1c0/0x1108)
	[<c01ded08>] (do_last.isra.24+0x0/0x1108) from [<c01dff04>] (path_openat.isra.25+0xf4/0x648)
	[<c01dfe10>] (path_openat.isra.25+0x0/0x648) from [<c01e1458>] (do_filp_open+0x3c/0x88)
	[<c01e141c>] (do_filp_open+0x0/0x88) from [<c01ccb28>] (do_sys_open+0xf0/0x198)
	 r7:00000001 r6:c0ea2180 r5:0000000b r4:00000000
	[<c01cca38>] (do_sys_open+0x0/0x198) from [<c01ccc00>] (SyS_open+0x30/0x34)
	[<c01ccbd0>] (SyS_open+0x0/0x34) from [<c001db80>] (ret_fast_syscall+0x0/0x48)
	Read of size 4 by thread T834:
	Memory state around the buggy address:
	 c4635380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	 c4635400: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
	 c4635480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	 c4635500: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
	 c4635580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	>c4635600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
	           ^
	 c4635680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
	 c4635700: 00 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc
	 c4635780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	 c4635800: 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc fc
	 c4635880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
	==================================================================
Signed-off-by: NAndrey Ryabinin <a.ryabinin@samsung.com>
Cc: <stable@vger.kernel.org>

During UDS connection check, both sides are checked for write access to
the other side. But only the first check is performed with audit support.
The second one didn't produce any audit logs. This simple patch fixes that.
Signed-off-by: NRafal Krypa <r.krypa@samsung.com>

Smack uses CIPSO to label internet packets and thus provide
for access control on delivery of packets. The netfilter facility
was not used to allow for Smack to work properly without netfilter
configuration. Smack does not need netfilter, however there are
cases where it would be handy.

As a side effect, the labeling of local IPv4 packets can be optimized
and the handling of local IPv6 packets is just all out better.

The best part is that the netfilter tools use "contexts" that
are just strings, and they work just as well for Smack as they
do for SELinux.

All of the conditional compilation for IPv6 was implemented
by Rafal Krypa <r.krypa@samsung.com>
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>

This is one of those cases where you look at code you did
years ago and wonder what you might have been thinking.
There are a number of LSM hooks that work off of file pointers,
and most of them really want the security data from the inode.
Some, however, really want the security context that the process
had when the file was opened. The difference went undetected in
Smack until it started getting used in a real system with real
testing. At that point it was clear that something was amiss.

This patch corrects the misuse of the f_security value in several
of the hooks. The behavior will not usually be any different, as
the process had to be able to open the file in the first place, and
the old check almost always succeeded, as will the new, but for
different reasons.

Thanks to the Samsung Tizen development team that identified this.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>

The 54e70ec5 commit introduced a
bidirectional check that should have checked for mutual WRITE access
between two labels. Due to a typo subject's OUT label is checked with
object's OUT. Should be OUT to IN.
Signed-off-by: NZbigniew Jasinski <z.jasinski@samsung.com>

Files created with __shmem_file_stup() appear to have somewhat fake
dentries which make them look like root directories and not get
the label the current process or ("*") star meant for tmpfs files.
Signed-off-by: NŁukasz Stelmach <l.stelmach@samsung.com>

In principle if this function was called with "value" == NULL and "len"
not NULL it could return different results for the "len" compared to a
case where "name" was not NULL. This is a hypothetical case that does
not exist in the kernel, but it's a logic bug nonetheless.
Signed-off-by: NLukasz Pawelczyk <l.pawelczyk@samsung.com>

Signed-off-by: NLukasz Pawelczyk <l.pawelczyk@samsung.com>

Setting smack label on file (e.g. 'attr -S -s SMACK64 -V "test" test')
triggered following spew on the kernel with KASan applied:
    ==================================================================
    BUG: AddressSanitizer: out of bounds access in strncpy+0x28/0x60 at addr ffff8800059ad064
    =============================================================================
    BUG kmalloc-8 (Not tainted): kasan error
    -----------------------------------------------------------------------------

    Disabling lock debugging due to kernel taint
    INFO: Slab 0xffffea0000166b40 objects=128 used=7 fp=0xffff8800059ad080 flags=0x4000000000000080
    INFO: Object 0xffff8800059ad060 @offset=96 fp=0xffff8800059ad080

    Bytes b4 ffff8800059ad050: a0 df 9a 05 00 88 ff ff 5a 5a 5a 5a 5a 5a 5a 5a  ........ZZZZZZZZ
    Object ffff8800059ad060: 74 65 73 74 6b 6b 6b a5                          testkkk.
    Redzone ffff8800059ad068: cc cc cc cc cc cc cc cc                          ........
    Padding ffff8800059ad078: 5a 5a 5a 5a 5a 5a 5a 5a                          ZZZZZZZZ
    CPU: 0 PID: 528 Comm: attr Tainted: G    B          3.18.0-rc1-mm1+ #5
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
     0000000000000000 ffff8800059ad064 ffffffff81534cf2 ffff880005a5bc40
     ffffffff8112fe1a 0000000100800006 0000000f059ad060 ffff880006000f90
     0000000000000296 ffffea0000166b40 ffffffff8107ca97 ffff880005891060
    Call Trace:
    ? dump_stack (lib/dump_stack.c:52)
    ? kasan_report_error (mm/kasan/report.c:102 mm/kasan/report.c:178)
    ? preempt_count_sub (kernel/sched/core.c:2651)
    ? __asan_load1 (mm/kasan/kasan.h:50 mm/kasan/kasan.c:248 mm/kasan/kasan.c:358)
    ? strncpy (lib/string.c:121)
    ? strncpy (lib/string.c:121)
    ? smk_parse_smack (security/smack/smack_access.c:457)
    ? setxattr (fs/xattr.c:343)
    ? smk_import_entry (security/smack/smack_access.c:514)
    ? smack_inode_setxattr (security/smack/smack_lsm.c:1093 (discriminator 1))
    ? security_inode_setxattr (security/security.c:602)
    ? vfs_setxattr (fs/xattr.c:134)
    ? setxattr (fs/xattr.c:343)
    ? setxattr (fs/xattr.c:360)
    ? get_parent_ip (kernel/sched/core.c:2606)
    ? preempt_count_sub (kernel/sched/core.c:2651)
    ? __percpu_counter_add (arch/x86/include/asm/preempt.h:98 lib/percpu_counter.c:90)
    ? get_parent_ip (kernel/sched/core.c:2606)
    ? preempt_count_sub (kernel/sched/core.c:2651)
    ? __mnt_want_write (arch/x86/include/asm/preempt.h:98 fs/namespace.c:359)
    ? path_setxattr (fs/xattr.c:380)
    ? SyS_lsetxattr (fs/xattr.c:397)
    ? system_call_fastpath (arch/x86/kernel/entry_64.S:423)
    Read of size 1 by task attr:
    Memory state around the buggy address:
     ffff8800059ace80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
     ffff8800059acf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
     ffff8800059acf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
    >ffff8800059ad000: 00 fc fc fc 00 fc fc fc 05 fc fc fc 04 fc fc fc
                                                           ^
     ffff8800059ad080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
     ffff8800059ad100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
     ffff8800059ad180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
    ==================================================================

strncpy() copies one byte more than the source string has.
Fix this by passing the correct length to strncpy().

Now we can remove initialization of the last byte in 'smack' string
because kzalloc() already did this for us.
Signed-off-by: NAndrey Ryabinin <a.ryabinin@samsung.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The patch use kmem_cache to allocate/free inode_smack since they are
alloced in high volumes making it a perfect case for kmem_cache.

As per analysis, 24 bytes of memory is wasted per allocation due
to internal fragmentation. With kmem_cache, this can be avoided.

Accounting of memory allocation is below :
 total       slack            net      count-alloc/free        caller
Before (with kzalloc)
1919872      719952          1919872      29998/0          new_inode_smack+0x14

After (with kmem_cache)
1201680          0           1201680      30042/0          new_inode_smack+0x18

>From above data, we found that 719952 bytes(~700 KB) of memory is
saved on allocation of 29998 smack inodes.
Signed-off-by: NRohit <rohit.kr@samsung.com>