30 Dec, 2020
1 commit
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[ Upstream commit 942cb357ae7d9249088e3687ee6a00ed2745a0c7 ]
Smack assumes that kernel threads are privileged for smackfs
operations. This was necessary because the credential of the
kernel thread was not related to a user operation. With io_uring
the credential does reflect a user's rights and can be used.Suggested-by: Jens Axboe
Acked-by: Jens Axboe
Acked-by: Eric W. Biederman
Signed-off-by: Casey Schaufler
Signed-off-by: Sasha Levin
12 Sep, 2020
1 commit
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Utilize the Netlabel cache mechanism for incoming packet matching.
Refactor the initialization of secattr structures, as it was being
done in two places.Signed-off-by: Casey Schaufler
05 Sep, 2019
1 commit
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inode_smack::smk_lock is taken during smack_d_instantiate(), which is
called during a filesystem transaction when creating a file on ext4.
Therefore to avoid a deadlock, all code that takes this lock must use
GFP_NOFS, to prevent memory reclaim from waiting for the filesystem
transaction to complete.Reported-by: syzbot+0eefc1e06a77d327a056@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers
Signed-off-by: Casey Schaufler
05 Jun, 2019
1 commit
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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 2extracted 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
Reviewed-by: Allison Randal
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081036.435762997@linutronix.de
Signed-off-by: Greg Kroah-Hartman
11 Jan, 2019
1 commit
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This patch provides a general mechanism for passing flags to the
security_capable LSM hook. It replaces the specific 'audit' flag that is
used to tell security_capable whether it should log an audit message for
the given capability check. The reason for generalizing this flag
passing is so we can add an additional flag that signifies whether
security_capable is being called by a setid syscall (which is needed by
the proposed SafeSetID LSM).Signed-off-by: Micah Morton
Reviewed-by: Kees Cook
Signed-off-by: James Morris
09 Jan, 2019
1 commit
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Don't use the cred->security pointer directly.
Provide a helper function that provides the security blob pointer.Signed-off-by: Casey Schaufler
Reviewed-by: Kees Cook
[kees: adjusted for ordered init series]
Signed-off-by: Kees Cook
11 Jan, 2018
1 commit
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Smack: Privilege check on key operations
Operations on key objects are subjected to Smack policy
even if the process is privileged. This is inconsistent
with the general behavior of Smack and may cause issues
with authentication by privileged daemons. This patch
allows processes with CAP_MAC_OVERRIDE to access keys
even if the Smack rules indicate otherwise.Reported-by: Jose Bollo
Signed-off-by: Casey Schaufler
02 Jun, 2017
1 commit
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Use cap_capable() rather than capable() in the Smack privilege
check as the former does not invoke other security module
privilege check, while the later does. This becomes important
when stacking. It may be a problem even with minor modules.Signed-off-by: Casey Schaufler
05 Apr, 2017
1 commit
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Since all callers of smk_netlbl_mls() are GFP_KERNEL context
(smk_set_cipso() calls memdup_user_nul(), init_smk_fs() calls
__kernfs_new_node(), smk_import_entry() calls kzalloc(GFP_KERNEL)),
it is safe to use GFP_KERNEL from netlbl_catmap_setbit().Signed-off-by: Tetsuo Handa
Signed-off-by: Casey Schaufler
16 Nov, 2016
1 commit
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The invalid Smack label ("") and the Huh ("?") Smack label
serve the same purpose and having both is unnecessary.
While pulling out the invalid label it became clear that
the use of smack_from_secid() was inconsistent, so that
is repaired. The setting of inode labels to the invalid
label could never happen in a functional system, has
never been observed in the wild and is not what you'd
really want for a failure behavior in any case. That is
removed.Signed-off-by: Casey Schaufler
11 Jun, 2016
1 commit
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We always mixed in the parent pointer into the dentry name hash, but we
did it late at lookup time. It turns out that we can simplify that
lookup-time action by salting the hash with the parent pointer early
instead of late.A few other users of our string hashes also wanted to mix in their own
pointers into the hash, and those are updated to use the same mechanism.Hash users that don't have any particular initial salt can just use the
NULL pointer as a no-salt.Cc: Vegard Nossum
Cc: George Spelvin
Cc: Al Viro
Signed-off-by: Linus Torvalds
20 Oct, 2015
1 commit
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This feature introduces new kernel interface:
- /relabel-self - for setting transition labels list
This list is used to control smack label transition mechanism.
List is set by, and per process. Process can transit to new label only if
label is on the list. Only process with CAP_MAC_ADMIN capability can add
labels to this list. With this list, process can change it's label without
CAP_MAC_ADMIN but only once. After label changing, list is unset.Changes in v2:
* use list_for_each_entry instead of _rcu during label write
* added missing description in security/Smack.txtChanges in v3:
* squashed into one commitChanges in v4:
* switch from global list to per-task list
* since the per-task list is accessed only by the task itself
there is no need to use synchronization mechanisms on itChanges in v5:
* change smackfs interface of relabel-self to the one used for onlycap
multiple labels are accepted, separated by space, which
replace the previous list upon writeSigned-off-by: Zbigniew Jasinski
Signed-off-by: Rafal Krypa
Acked-by: Casey Schaufler
11 Aug, 2015
1 commit
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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: Roman Kubiak
Acked-by: Casey Schaufler
03 Jun, 2015
1 commit
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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: Rafal Krypa
15 May, 2015
1 commit
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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: Lukasz Pawelczyk
24 Mar, 2015
1 commit
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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: Casey Schaufler
22 Nov, 2014
1 commit
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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=0xffff8800059ad080Bytes 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: Andrey Ryabinin
28 Oct, 2014
1 commit
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The lock access mode allows setting a read lock on a file
for with the process has only read access. The floor label is
defined to make it easy to have the basic system installed such
that everyone can read it. Once there's a desire to read lock
(rationally or otherwise) a floor file a rule needs to get set.
This happens all the time, so make the floor label a little bit
more special and allow everyone lock access, too. By implication,
give processes with the hat label (hat can read everything)
lock access as well. This reduces clutter in the Smack rule set.Signed-off-by: Casey Schaufler
30 Aug, 2014
1 commit
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Smack used to use a mix of smack_known struct and char* throughout its
APIs and implementation. This patch unifies the behaviour and makes it
store and operate exclusively on smack_known struct pointers when managing
labels.Signed-off-by: Lukasz Pawelczyk
Conflicts:
security/smack/smack_access.c
security/smack/smack_lsm.c
29 Aug, 2014
1 commit
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People keep asking me for permissive mode, and I keep saying "no".
Permissive mode is wrong for more reasons than I can enumerate,
but the compelling one is that it's once on, never off.Nonetheless, there is an argument to be made for running a
process with lots of permissions, logging which are required,
and then locking the process down. There wasn't a way to do
that with Smack, but this provides it.The notion is that you start out by giving the process an
appropriate Smack label, such as "ATBirds". You create rules
with a wide range of access and the "b" mode. On Tizen it
might be:ATBirds System rwxalb
ATBirds User rwxalb
ATBirds _ rwxalb
User ATBirds wb
System ATBirds wbAccesses that fail will generate audit records. Accesses
that succeed because of rules marked with a "b" generate
log messages identifying the rule, the program and as much
object information as is convenient.When the system is properly configured and the programs
brought in line with the labeling scheme the "b" mode can
be removed from the rules. When the system is ready for
production the facility can be configured out.This provides the developer the convenience of permissive
mode without creating a system that looks like it is
enforcing a policy while it is not.Signed-off-by: Casey Schaufler
02 Aug, 2014
1 commit
01 Aug, 2014
3 commits
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Historically the NetLabel LSM secattr catmap functions and data
structures have had very long names which makes a mess of the NetLabel
code and anyone who uses NetLabel. This patch renames the catmap
functions and structures from "*_secattr_catmap_*" to just "*_catmap_*"
which improves things greatly.There are no substantial code or logic changes in this patch.
Signed-off-by: Paul Moore
Tested-by: Casey Schaufler -
The NetLabel secattr catmap functions, and the SELinux import/export
glue routines, were broken in many horrible ways and the SELinux glue
code fiddled with the NetLabel catmap structures in ways that we
probably shouldn't allow. At some point this "worked", but that was
likely due to a bit of dumb luck and sub-par testing (both inflicted
by yours truly). This patch corrects these problems by basically
gutting the code in favor of something less obtuse and restoring the
NetLabel abstractions in the SELinux catmap glue code.Everything is working now, and if it decides to break itself in the
future this code will be much easier to debug than the code it
replaces.One noteworthy side effect of the changes is that it is no longer
necessary to allocate a NetLabel catmap before calling one of the
NetLabel APIs to set a bit in the catmap. NetLabel will automatically
allocate the catmap nodes when needed, resulting in less allocations
when the lowest bit is greater than 255 and less code in the LSMs.Cc: stable@vger.kernel.org
Reported-by: Christian Evans
Signed-off-by: Paul Moore
Tested-by: Casey Schaufler -
The NetLabel category (catmap) functions have a problem in that they
assume categories will be set in an increasing manner, e.g. the next
category set will always be larger than the last. Unfortunately, this
is not a valid assumption and could result in problems when attempting
to set categories less than the startbit in the lowest catmap node.
In some cases kernel panics and other nasties can result.This patch corrects the problem by checking for this and allocating a
new catmap node instance and placing it at the front of the list.Cc: stable@vger.kernel.org
Reported-by: Christian Evans
Signed-off-by: Paul Moore
Tested-by: Casey Schaufler
12 Apr, 2014
2 commits
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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 -
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
19 Oct, 2013
1 commit
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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
02 Aug, 2013
1 commit
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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 | 0.627Surprisingly, 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
29 May, 2013
2 commits
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netlbl_secattr_catmap_alloc(GFP_ATOMIC) can return NULL.
Signed-off-by: Tetsuo Handa
-
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
20 Mar, 2013
1 commit
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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
14 Jul, 2012
1 commit
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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
15 May, 2012
1 commit
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V4 updated to current linux-security#next
Targeted for git://gitorious.org/smack-next/kernel.gitModern 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 likesoftwarehouse-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
04 Apr, 2012
2 commits
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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
-
Linus found that the gigantic size of the common audit data caused a big
perf hit on something as simple as running stat() in a loop. This patch
requires LSMs to declare the LSM specific portion separately rather than
doing it in a union. Thus each LSM can be responsible for shrinking their
portion and don't have to pay a penalty just because other LSMs have a
bigger space requirement.Signed-off-by: Eric Paris
Signed-off-by: Linus Torvalds
21 Oct, 2011
1 commit
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Allow query access as a normal user removing the need
for CAP_MAC_ADMIN. Give RW access to /smack/access
for UGO. Do not import smack labels in access check.Signed-off-by: Jarkko Sakkinen
Signed-off-by: Casey Schaufler
13 Oct, 2011
1 commit
-
This patch is targeted for the smack-next tree.
Smack access checks suffer from two significant performance
issues. In cases where there are large numbers of rules the
search of the single list of rules is wasteful. Comparing the
string values of the smack labels is less efficient than a
numeric comparison would.These changes take advantage of the Smack label list, which
maintains the mapping of Smack labels to secids and optional
CIPSO labels. Because the labels are kept perpetually, an
access check can be done strictly based on the address of the
label in the list without ever looking at the label itself.
Rather than keeping one global list of rules the rules with
a particular subject label can be based off of that label
list entry. The access check need never look at entries that
do not use the current subject label.This requires that packets coming off the network with
CIPSO direct Smack labels that have never been seen before
be treated carefully. The only case where they could be
delivered is where the receiving socket has an IPIN star
label, so that case is explicitly addressed.On a system with 39,800 rules (200 labels in all permutations)
a system with this patch runs an access speed test in 5% of
the time of the old version. That should be a best case
improvement. If all of the rules are associated with the
same subject label and all of the accesses are for processes
with that label (unlikely) the improvement is about 30%.Signed-off-by: Casey Schaufler
31 Mar, 2011
1 commit
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Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: Lucas De Marchi
18 Jan, 2011
1 commit
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In the embedded world there are often situations
where libraries are updated from a variety of sources,
for a variety of reasons, and with any number of
security characteristics. These differences
might include privilege required for a given library
provided interface to function properly, as occurs
from time to time in graphics libraries. There are
also cases where it is important to limit use of
libraries based on the provider of the library and
the security aware application may make choices
based on that criteria.These issues are addressed by providing an additional
Smack label that may optionally be assigned to an object,
the SMACK64MMAP attribute. An mmap operation is allowed
if there is no such attribute.If there is a SMACK64MMAP attribute the mmap is permitted
only if a subject with that label has all of the access
permitted a subject with the current task label.Security aware applications may from time to time
wish to reduce their "privilege" to avoid accidental use
of privilege. One case where this arises is the
environment in which multiple sources provide libraries
to perform the same functions. An application may know
that it should eschew services made available from a
particular vendor, or of a particular version.In support of this a secondary list of Smack rules has
been added that is local to the task. This list is
consulted only in the case where the global list has
approved access. It can only further restrict access.
Unlike the global last, if no entry is found on the
local list access is granted. An application can add
entries to its own list by writing to /smack/load-self.The changes appear large as they involve refactoring
the list handling to accomodate there being more
than one rule list.Signed-off-by: Casey Schaufler
08 Dec, 2010
1 commit
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In a situation where Smack access rules allow processes
with multiple labels to write to a directory it is easy
to get into a situation where the directory gets cluttered
with files that the owner can't deal with because while
they could be written to the directory a process at the
label of the directory can't write them. This is generally
the desired behavior, but when it isn't it is a real
issue.This patch introduces a new attribute SMACK64TRANSMUTE that
instructs Smack to create the file with the label of the directory
under certain circumstances.A new access mode, "t" for transmute, is made available to
Smack access rules, which are expanded from "rwxa" to "rwxat".
If a file is created in a directory marked as transmutable
and if access was granted to perform the operation by a rule
that included the transmute mode, then the file gets the
Smack label of the directory instead of the Smack label of the
creating process.Note that this is equivalent to creating an empty file at the
label of the directory and then having the other process write
to it. The transmute scheme requires that both the access rule
allows transmutation and that the directory be explicitly marked.Signed-off-by: Jarkko Sakkinen
Signed-off-by: Casey Schaufler
