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2019-01-08Smack: Abstract use of cred security blobCasey Schaufler
Don't use the cred->security pointer directly. Provide a helper function that provides the security blob pointer. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> [kees: adjusted for ordered init series] Signed-off-by: Kees Cook <keescook@chromium.org>
2018-01-10Smack: Privilege check on key operationsCasey Schaufler
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 <jobol@nonadev.net> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-06-01Smack: Use cap_capable in privilege checkCasey Schaufler
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 <casey@schaufler-ca.com>
2017-04-04Smack: Use GFP_KERNEL for smk_netlbl_mls().Tetsuo Handa
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 <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-15Smack: Remove unnecessary smack_known_invalidCasey Schaufler
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 <casey@schaufler-ca.com>
2016-06-10vfs: make the string hashes salt the hashLinus Torvalds
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 <vegard.nossum@oracle.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-19Smack: limited capability for changing process labelZbigniew Jasinski
This feature introduces new kernel interface: - <smack_fs>/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.txt Changes in v3: * squashed into one commit Changes 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 it Changes 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 write Signed-off-by: Zbigniew Jasinski <z.jasinski@samsung.com> Signed-off-by: Rafal Krypa <r.krypa@samsung.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2015-08-10Kernel threads excluded from smack checksRoman Kubiak
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 <r.kubiak@samsung.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2015-06-02Smack: allow multiple labels in onlycapRafal Krypa
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 <r.krypa@samsung.com>
2015-05-15smack: pass error code through pointersLukasz Pawelczyk
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 <l.pawelczyk@samsung.com>
2015-03-23Smack: Allow an unconfined label in bringup modeCasey Schaufler
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 <casey@schaufler-ca.com>
2014-11-21security: smack: fix out-of-bounds access in smk_parse_smack()Andrey Ryabinin
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: Andrey Ryabinin <a.ryabinin@samsung.com>
2014-10-28Smack: Lock mode for the floor and hat labelsCasey Schaufler
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 <casey@schaufler-ca.com>
2014-08-29Make Smack operate on smack_known struct where it still used char*Lukasz Pawelczyk
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 <l.pawelczyk@samsung.com> Conflicts: security/smack/smack_access.c security/smack/smack_lsm.c
2014-08-28Smack: Bring-up access modeCasey Schaufler
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 wb Accesses 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 <casey@schaufler-ca.com>
2014-08-02Merge branch 'next' of git://git.infradead.org/users/pcmoore/selinux into nextJames Morris
2014-08-01netlabel: shorter names for the NetLabel catmap funcs/structsPaul Moore
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 <pmoore@redhat.com> Tested-by: Casey Schaufler <casey@schaufler-ca.com>
2014-08-01netlabel: fix the horribly broken catmap functionsPaul Moore
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 <frodox@zoho.com> Signed-off-by: Paul Moore <pmoore@redhat.com> Tested-by: Casey Schaufler <casey@schaufler-ca.com>
2014-08-01netlabel: fix a problem when setting bits below the previously lowest bitPaul Moore
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 <frodox@zoho.com> Signed-off-by: Paul Moore <pmoore@redhat.com> Tested-by: Casey Schaufler <casey@schaufler-ca.com>
2014-04-11Smack: adds smackfs/ptrace interfaceLukasz Pawelczyk
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 <l.pawelczyk@partner.samsung.com> Signed-off-by: Rafal Krypa <r.krypa@samsung.com>
2014-04-11Smack: fix the subject/object order in smack_ptrace_traceme()Lukasz Pawelczyk
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 <l.pawelczyk@partner.samsung.com> Signed-off-by: Rafal Krypa <r.krypa@samsung.com>
2013-10-18Smack: Implement lock security modeCasey Schaufler
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 <casey@schaufler-ca.com>
2013-08-01security: smack: add a hash table to quicken smk_find_entry()Tomasz Stanislawski
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 <t.stanislaws@samsung.com>
2013-05-28Smack: Fix possible NULL pointer dereference at smk_netlbl_mls()Tetsuo Handa
netlbl_secattr_catmap_alloc(GFP_ATOMIC) can return NULL. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
2013-05-28Smack: Improve access check performanceCasey Schaufler
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 <casey@schaufler-ca.com>
2013-03-19Smack: add missing support for transmute bit in smack_str_from_perm()Rafal Krypa
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 <r.krypa@samsung.com>
2012-07-13Smack: onlycap limits on CAP_MAC_ADMINCasey Schaufler
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 <casey@schaufler-ca.com>
2012-05-14Smack: allow for significantly longer Smack labels v4Casey Schaufler
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 <casey@schaufler-ca.com>
2012-04-03lsm_audit: don't specify the audit pre/post callbacks in 'struct ↵Linus Torvalds
common_audit_data' 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 <torvalds@linux-foundation.org>
2012-04-03LSM: shrink sizeof LSM specific portion of common_audit_dataEric Paris
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 <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-20Smack: allow to access /smack/access as normal userJarkko Sakkinen
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 <jarkko.j.sakkinen@gmail.com> Signed-off-by: Casey Schaufler <cschaufler@cschaufler-intel.(none)>
2011-10-12Smack: Rule list lookup performanceCasey Schaufler
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 <casey@schaufler-ca.com>
2011-03-31Fix common misspellingsLucas De Marchi
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-01-17Subject: [PATCH] Smack: mmap controls for library containmentCasey Schaufler
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 <casey@schaufler-ca.com>
2010-12-07Smack: Transmute labels on specified directoriesJarkko Sakkinen
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 <ext-jarkko.2.sakkinen@nokia.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2010-12-02This patch adds a new security attribute to Smack calledCasey Schaufler
SMACK64EXEC. It defines label that is used while task is running. Exception: in smack_task_wait() child task is checked for write access to parent task using label inherited from the task that forked it. Fixed issues from previous submit: - SMACK64EXEC was not read when SMACK64 was not set. - inode security blob was not updated after setting SMACK64EXEC - inode security blob was not updated when removing SMACK64EXEC
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2009-07-10security: Make lsm_priv union in lsm_audit.h anonymousThomas Liu
Made the lsm_priv union in include/linux/lsm_audit.h anonymous. Signed-off-by: Thomas Liu <tliu@redhat.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-07-10Move variable function in lsm_audit.h into SMACK private spaceThomas Liu
Moved variable function in include/linux/lsm_audit.h into the smack_audit_data struct since it is never used outside of it. Also removed setting of function in the COMMON_AUDIT_DATA_INIT macro because that variable is now private to SMACK. Signed-off-by: Thomas Liu <tliu@redhat.com> Acked-by: Eric Paris <eparis@redhat.com> I-dont-see-any-problems-with-it: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-04-14smack: implement logging V3Etienne Basset
the following patch, add logging of Smack security decisions. This is of course very useful to understand what your current smack policy does. As suggested by Casey, it also now forbids labels with ', " or \ It introduces a '/smack/logging' switch : 0: no logging 1: log denied (default) 2: log accepted 3: log denied&accepted Signed-off-by: Etienne Basset <etienne.basset@numericable.fr> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-03-28smack: Add a new '-CIPSO' option to the network address label configurationEtienne Basset
This patch adds a new special option '-CIPSO' to the Smack subsystem. When used in the netlabel list, it means "use CIPSO networking". A use case is when your local network speaks CIPSO and you want also to connect to the unlabeled Internet. This patch also add some documentation describing that. The patch also corrects an oops when setting a '' SMACK64 xattr to a file. Signed-off-by: Etienne Basset <etienne.basset@numericable.fr> Signed-off-by: Paul Moore <paul.moore@hp.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-03-26smack: convert smack to standard linux listsEtienne Basset
the following patch (on top of 2.6.29) converts Smack lists to standard linux lists Please review and consider for inclusion in 2.6.30-rc regards, Etienne Signed-off-by: Etienne Basset <etienne.basset@numericable.fr> Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2009-02-19smack: fix lots of kernel-doc notationRandy Dunlap
Fix/add kernel-doc notation and fix typos in security/smack/. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <jmorris@namei.org>
2008-12-31smack: Add support for unlabeled network hosts and networksCasey Schaufler
Add support for unlabeled network hosts and networks. Relies heavily on Paul Moore's netlabel support. Creates a new entry in /smack called netlabel. Writes to /smack/netlabel take the form: A.B.C.D LABEL or A.B.C.D/N LABEL where A.B.C.D is a network address, N is an integer between 0-32, and LABEL is the Smack label to be used. If /N is omitted /32 is assumed. N designates the netmask for the address. Entries are matched by the most specific address/mask pair. 0.0.0.0/0 will match everything, while 192.168.1.117/32 will match exactly one host. A new system label "@", pronounced "web", is defined. Processes can not be assigned the web label. An address assigned the web label can be written to by any process, and packets coming from a web address can be written to any socket. Use of the web label is a violation of any strict MAC policy, but the web label has been requested many times. The nltype entry has been removed from /smack. It did not work right and the netlabel interface can be used to specify that all hosts be treated as unlabeled. CIPSO labels on incoming packets will be honored, even from designated single label hosts. Single label hosts can only be written to by processes with labels that can write to the label of the host. Packets sent to single label hosts will always be unlabeled. Once added a single label designation cannot be removed, however the label may be changed. The behavior of the ambient label remains unchanged. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul.moore@hp.com>
2008-11-14CRED: Wrap current->cred and a few other accessorsDavid Howells
Wrap current->cred and a few other accessors to hide their actual implementation. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14CRED: Separate task security context from task_structDavid Howells
Separate the task security context from task_struct. At this point, the security data is temporarily embedded in the task_struct with two pointers pointing to it. Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in entry.S via asm-offsets. With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2008-08-05smack: limit privilege by labelCasey Schaufler
There have been a number of requests to make the Smack LSM enforce MAC even in the face of privilege, either capability based or superuser based. This is not universally desired, however, so it seems desirable to make it optional. Further, at least one legacy OS implemented a scheme whereby only processes running with one particular label could be exempt from MAC. This patch supports these three cases. If /smack/onlycap is empty (unset or null-string) privilege is enforced in the normal way. If /smack/onlycap contains a label only processes running with that label may be MAC exempt. If the label in /smack/onlycap is the star label ("*") the semantics of the star label combine with the privilege restrictions to prevent any violations of MAC, even in the presence of privilege. Again, this will be independent of the privilege scheme. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: James Morris <jmorris@namei.org>
2008-02-05Smack: Simplified Mandatory Access Control KernelCasey Schaufler
Smack is the Simplified Mandatory Access Control Kernel. Smack implements mandatory access control (MAC) using labels attached to tasks and data containers, including files, SVIPC, and other tasks. Smack is a kernel based scheme that requires an absolute minimum of application support and a very small amount of configuration data. Smack uses extended attributes and provides a set of general mount options, borrowing technics used elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides a pseudo-filesystem smackfs that is used for manipulation of system Smack attributes. The patch, patches for ls and sshd, a README, a startup script, and x86 binaries for ls and sshd are also available on http://www.schaufler-ca.com Development has been done using Fedora Core 7 in a virtual machine environment and on an old Sony laptop. Smack provides mandatory access controls based on the label attached to a task and the label attached to the object it is attempting to access. Smack labels are deliberately short (1-23 characters) text strings. Single character labels using special characters are reserved for system use. The only operation applied to Smack labels is equality comparison. No wildcards or expressions, regular or otherwise, are used. Smack labels are composed of printable characters and may not include "/". A file always gets the Smack label of the task that created it. Smack defines and uses these labels: "*" - pronounced "star" "_" - pronounced "floor" "^" - pronounced "hat" "?" - pronounced "huh" The access rules enforced by Smack are, in order: 1. Any access requested by a task labeled "*" is denied. 2. A read or execute access requested by a task labeled "^" is permitted. 3. A read or execute access requested on an object labeled "_" is permitted. 4. Any access requested on an object labeled "*" is permitted. 5. Any access requested by a task on an object with the same label is permitted. 6. Any access requested that is explicitly defined in the loaded rule set is permitted. 7. Any other access is denied. Rules may be explicitly defined by writing subject,object,access triples to /smack/load. Smack rule sets can be easily defined that describe Bell&LaPadula sensitivity, Biba integrity, and a variety of interesting configurations. Smack rule sets can be modified on the fly to accommodate changes in the operating environment or even the time of day. Some practical use cases: Hierarchical levels. The less common of the two usual uses for MLS systems is to define hierarchical levels, often unclassified, confidential, secret, and so on. To set up smack to support this, these rules could be defined: C Unclass rx S C rx S Unclass rx TS S rx TS C rx TS Unclass rx A TS process can read S, C, and Unclass data, but cannot write it. An S process can read C and Unclass. Note that specifying that TS can read S and S can read C does not imply TS can read C, it has to be explicitly stated. Non-hierarchical categories. This is the more common of the usual uses for an MLS system. Since the default rule is that a subject cannot access an object with a different label no access rules are required to implement compartmentalization. A case that the Bell & LaPadula policy does not allow is demonstrated with this Smack access rule: A case that Bell&LaPadula does not allow that Smack does: ESPN ABC r ABC ESPN r On my portable video device I have two applications, one that shows ABC programming and the other ESPN programming. ESPN wants to show me sport stories that show up as news, and ABC will only provide minimal information about a sports story if ESPN is covering it. Each side can look at the other's info, neither can change the other. Neither can see what FOX is up to, which is just as well all things considered. Another case that I especially like: SatData Guard w Guard Publish w A program running with the Guard label opens a UDP socket and accepts messages sent by a program running with a SatData label. The Guard program inspects the message to ensure it is wholesome and if it is sends it to a program running with the Publish label. This program then puts the information passed in an appropriate place. Note that the Guard program cannot write to a Publish file system object because file system semanitic require read as well as write. The four cases (categories, levels, mutual read, guardbox) here are all quite real, and problems I've been asked to solve over the years. The first two are easy to do with traditonal MLS systems while the last two you can't without invoking privilege, at least for a while. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Cc: Joshua Brindle <method@manicmethod.com> Cc: Paul Moore <paul.moore@hp.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Chris Wright <chrisw@sous-sol.org> Cc: James Morris <jmorris@namei.org> Cc: "Ahmed S. Darwish" <darwish.07@gmail.com> Cc: Andrew G. Morgan <morgan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>