linux-toradex.git/security/smack/smack_access.c, branch v3.16-rc7

Smack: adds smackfs/ptrace interface

2014-04-11T21:34:35+00:00

This allows to limit ptrace beyond the regular smack access rules.
It adds a smackfs/ptrace interface that allows smack to be configured
to require equal smack labels for PTRACE_MODE_ATTACH access.
See the changes in Documentation/security/Smack.txt below for details.

Signed-off-by: Lukasz Pawelczyk 
Signed-off-by: Rafal Krypa

Smack: fix the subject/object order in smack_ptrace_traceme()

2014-04-11T21:34:17+00:00

The order of subject/object is currently reversed in
smack_ptrace_traceme(). It is currently checked if the tracee has a
capability to trace tracer and according to this rule a decision is made
whether the tracer will be allowed to trace tracee.

Signed-off-by: Lukasz Pawelczyk 
Signed-off-by: Rafal Krypa

Smack: Implement lock security mode

2013-10-18T16:39:33+00:00

Linux file locking does not follow the same rules
as other mechanisms. Even though it is a write operation
a process can set a read lock on files which it has open
only for read access. Two programs with read access to
a file can use read locks to communicate.

This is not acceptable in a Mandatory Access Control
environment. Smack treats setting a read lock as the
write operation that it is. Unfortunately, many programs
assume that setting a read lock is a read operation.
These programs are unhappy in the Smack environment.

This patch introduces a new access mode (lock) to address
this problem. A process with lock access to a file can
set a read lock. A process with write access to a file can
set a read lock or a write lock. This prevents a situation
where processes are granted write access just so they can
set read locks.

Targeted for git://git.gitorious.org/smack-next/kernel.git

Signed-off-by: Casey Schaufler

security: smack: add a hash table to quicken smk_find_entry()

2013-08-01T23:55:20+00:00

Accepted for the smack-next tree after changing the number of
slots from 128 to 16.

This patch adds a hash table to quicken searching of a smack label by its name.

Basically, the patch improves performance of SMACK initialization.  Parsing of
rules involves translation from a string to a smack_known (aka label) entity
which is done in smk_find_entry().

The current implementation of the function iterates over a global list of
smack_known resulting in O(N) complexity for smk_find_entry().  The total
complexity of SMACK initialization becomes O(rules * labels).  Therefore it
scales quadratically with a complexity of a system.

Applying the patch reduced the complexity of smk_find_entry() to O(1) as long
as number of label is in hundreds. If the number of labels is increased please
update SMACK_HASH_SLOTS constant defined in security/smack/smack.h. Introducing
the configuration of this constant with Kconfig or cmdline might be a good
idea.

The size of the hash table was adjusted experimentally.  The rule set used by
TIZEN contains circa 17K rules for 500 labels.  The table above contains
results of SMACK initialization using 'time smackctl apply' bash command.
The 'Ref' is a kernel without this patch applied. The consecutive values
refers to value of SMACK_HASH_SLOTS.  Every measurement was repeated three
times to reduce noise.

     |  Ref  |   1   |   2   |   4   |   8   |   16  |   32  |   64  |  128  |  256  |  512
--------------------------------------------------------------------------------------------
Run1 | 1.156 | 1.096 | 0.883 | 0.764 | 0.692 | 0.667 | 0.649 | 0.633 | 0.634 | 0.629 | 0.620
Run2 | 1.156 | 1.111 | 0.885 | 0.764 | 0.694 | 0.661 | 0.649 | 0.651 | 0.634 | 0.638 | 0.623
Run3 | 1.160 | 1.107 | 0.886 | 0.764 | 0.694 | 0.671 | 0.661 | 0.638 | 0.631 | 0.624 | 0.638
AVG  | 1.157 | 1.105 | 0.885 | 0.764 | 0.693 | 0.666 | 0.653 | 0.641 | 0.633 | 0.630 | 0.627

Surprisingly, a single hlist is slightly faster than a double-linked list.
The speed-up saturates near 64 slots.  Therefore I chose value 128 to provide
some margin if more labels were used.
It looks that IO becomes a new bottleneck.

Signed-off-by: Tomasz Stanislawski

Smack: Fix possible NULL pointer dereference at smk_netlbl_mls()

2013-05-28T17:15:35+00:00

netlbl_secattr_catmap_alloc(GFP_ATOMIC) can return NULL.

Signed-off-by: Tetsuo Handa

Smack: Improve access check performance

2013-05-28T17:08:32+00:00

Each Smack label that the kernel has seen is added to a
list of labels. The list of access rules for a given subject
label hangs off of the label list entry for the label.
This patch changes the structures that contain subject
labels to point at the label list entry rather that the
label itself. Doing so removes a label list lookup in
smk_access() that was accounting for the largest single
chunk of Smack overhead.

Targeted for git://git.gitorious.org/smack-next/kernel.git

Signed-off-by: Casey Schaufler

Smack: add missing support for transmute bit in smack_str_from_perm()

2013-03-19T21:15:41+00:00

This fixes audit logs for granting or denial of permissions to show
information about transmute bit.

Targeted for git://git.gitorious.org/smack-next/kernel.git

Signed-off-by: Rafal Krypa

Smack: onlycap limits on CAP_MAC_ADMIN

2012-07-13T22:49:23+00:00

Smack is integrated with the POSIX capabilities scheme,
using the capabilities CAP_MAC_OVERRIDE and CAP_MAC_ADMIN to
determine if a process is allowed to ignore Smack checks or
change Smack related data respectively. Smack provides an
additional restriction that if an onlycap value is set
by writing to /smack/onlycap only tasks with that Smack
label are allowed to use CAP_MAC_OVERRIDE.

This change adds CAP_MAC_ADMIN as a capability that is affected
by the onlycap mechanism.

Targeted for git://git.gitorious.org/smack-next/kernel.git

Signed-off-by: Casey Schaufler

Smack: allow for significantly longer Smack labels v4

2012-05-15T05:48:38+00:00

V4 updated to current linux-security#next
Targeted for git://gitorious.org/smack-next/kernel.git

Modern application runtime environments like to use
naming schemes that are structured and generated without
human intervention. Even though the Smack limit of 23
characters for a label name is perfectly rational for
human use there have been complaints that the limit is
a problem in environments where names are composed from
a set or sources, including vendor, author, distribution
channel and application name. Names like

	softwarehouse-pgwodehouse-coolappstore-mellowmuskrats

are becoming harder to avoid. This patch introduces long
label support in Smack. Labels are now limited to 255
characters instead of the old 23.

The primary reason for limiting the labels to 23 characters
was so they could be directly contained in CIPSO category sets.
This is still done were possible, but for labels that are too
large a mapping is required. This is perfectly safe for communication
that stays "on the box" and doesn't require much coordination
between boxes beyond what would have been required to keep label
names consistent.

The bulk of this patch is in smackfs, adding and updating
administrative interfaces. Because existing APIs can't be
changed new ones that do much the same things as old ones
have been introduced.

The Smack specific CIPSO data representation has been removed
and replaced with the data format used by netlabel. The CIPSO
header is now computed when a label is imported rather than
on use. This results in improved IP performance. The smack
label is now allocated separately from the containing structure,
allowing for larger strings.

Four new /smack interfaces have been introduced as four
of the old interfaces strictly required labels be specified
in fixed length arrays.

The access interface is supplemented with the check interface:
	access  "Subject                 Object                  rwxat"
	access2 "Subject Object rwaxt"

The load interface is supplemented with the rules interface:
	load   "Subject                 Object                  rwxat"
	load2  "Subject Object rwaxt"

The load-self interface is supplemented with the self-rules interface:
	load-self   "Subject                 Object                  rwxat"
	load-self2  "Subject Object rwaxt"

The cipso interface is supplemented with the wire interface:
	cipso  "Subject                  lvl cnt  c1  c2 ..."
	cipso2 "Subject lvl cnt  c1  c2 ..."

The old interfaces are maintained for compatibility.

Signed-off-by: Casey Schaufler

lsm_audit: don't specify the audit pre/post callbacks in 'struct common_audit_data'

2012-04-03T16:49:59+00:00

It just bloats the audit data structure for no good reason, since the
only time those fields are filled are just before calling the
common_lsm_audit() function, which is also the only user of those
fields.

So just make them be the arguments to common_lsm_audit(), rather than
bloating that structure that is passed around everywhere, and is
initialized in hot paths.

Signed-off-by: Linus Torvalds