ima_path_check actually deals with files! call it ima_file_check instead.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
ima wants to create an inode information struct (iint) when inodes are
allocated. This means that at least the part of ima which does this
allocation (the allocation is filled with information later) should
before any inodes are created. To accomplish this we split the ima
initialization routine placing the kmem cache allocator inside a
security_initcall() function. Since this makes use of radix trees we also
need to make sure that is initialized before security_initcall().
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The "Untangling ima mess, part 2 with counters" patch messed
up the counters. Based on conversations with Al Viro, this patch
streamlines ima_path_check() by removing the counter maintaince.
The counters are now updated independently, from measuring the file,
in __dentry_open() and alloc_file() by calling ima_counts_get().
ima_path_check() is called from nfsd and do_filp_open().
It also did not measure all files that should have been measured.
Reason: ima_path_check() got bogus value passed as mask.
[AV: mea culpa]
[AV: add missing nfsd bits]
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Drop my typoed comment as it is both unhelpful and redundant.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Right now the syslog "type" action are just raw numbers which makes
the source difficult to follow. This patch replaces the raw numbers
with defined constants for some level of sanity.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
This allows the LSM to distinguish between syslog functions originating
from /proc/kmsg access and direct syscalls. By default, the commoncaps
will now no longer require CAP_SYS_ADMIN to read an opened /proc/kmsg
file descriptor. For example the kernel syslog reader can now drop
privileges after opening /proc/kmsg, instead of staying privileged with
CAP_SYS_ADMIN. MAC systems that implement security_syslog have unchanged
behavior.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
Allow runtime switching between different policy types (e.g. from a MLS/MCS
policy to a non-MLS/non-MCS policy or viceversa).
Signed-off-by: Guido Trentalancia <guido@trentalancia.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Always load the initial SIDs, even in the case of a policy
reload and not just at the initial policy load. This comes
particularly handy after the introduction of a recent
patch for enabling runtime switching between different
policy types, although this patch is in theory independent
from that feature.
Signed-off-by: Guido Trentalancia <guido@trentalancia.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
TOMOYO was using own memory usage counter for detecting memory leak.
But as kernel 2.6.31 introduced memory leak detection mechanism
( CONFIG_DEBUG_KMEMLEAK ), we no longer need to have own counter.
We remove usage counter for memory used for permission checks, but we keep
usage counter for memory used for policy so that we can apply quota.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
This patch removes dead code in type_attribute_bounds_av().
Due to the historical reason, the type boundary feature is delivered
from hierarchical types in libsepol, it has supported boundary features
both of subject type (domain; in most cases) and target type.
However, we don't have any actual use cases in bounded target types,
and it tended to make conceptual confusion.
So, this patch removes the dead code to apply boundary checks on the
target types. I makes clear the TYPEBOUNDS restricts privileges of
a certain domain bounded to any other domain.
Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
--
security/selinux/ss/services.c | 43 +++------------------------------------
1 files changed, 4 insertions(+), 39 deletions(-)
Signed-off-by: James Morris <jmorris@namei.org>
Per https://bugzilla.redhat.com/show_bug.cgi?id=548145
there are sufficient range transition rules in modern (Fedora) policy to
make mls_compute_sid a significant factor on the shmem file setup path
due to the length of the range_tr list. Replace the simple range_tr
list with a hashtab inside the security server to help mitigate this
problem.
Signed-off-by: Stephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
If allow_unknown==deny, SELinux treats an undefined kernel security
class as an error condition rather than as a typical permission denial
and thus does not allow permissions on undefined classes even when in
permissive mode. Change the SELinux logic so that this case is handled
as a typical permission denial, subject to the usual permissive mode and
permissive domain handling.
Also drop the 'requested' argument from security_compute_av() and
helpers as it is a legacy of the original security server interface and
is unused.
Changes:
- Handle permissive domains consistently by moving up the test for a
permissive domain.
- Make security_compute_av_user() consistent with security_compute_av();
the only difference now is that security_compute_av() performs mapping
between the kernel-private class and permission indices and the policy
values. In the userspace case, this mapping is handled by libselinux.
- Moved avd_init inside the policy lock.
Based in part on a patch by Paul Moore <paul.moore@hp.com>.
Reported-by: Andrew Worsley <amworsley@gmail.com>
Signed-off-by: Stephen D. Smalley <sds@tycho.nsa.gov>
Reviewed-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
Currently, the getsecurity and setsecurity operations return zero for
kernel private inodes, where xattrs are not available directly to
userspace.
This confuses some applications, and does not conform to the
man page for getxattr(2) etc., which state that these syscalls
should return ENOTSUP if xattrs are not supported or disabled.
Note that in the listsecurity case, we still need to return zero
as we don't know which other xattr handlers may be active.
For discussion of userland confusion, see:
http://www.mail-archive.com/bug-coreutils@gnu.org/msg17988.html
This patch corrects the error returns so that ENOTSUP is reported
to userspace as required.
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Serge Hallyn <serue@us.ibm.com>
commit 5300990c03 had stepped on a rather
nasty mess: definitions of ACC_MODE used to be different. Fixed the
resulting breakage, converting them to variant that takes O_... value;
all callers have that and it actually simplifies life (see tomoyo part
of changes).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently, TOMOYO allocates memory for list elements from memory pool allocated
by kmalloc(PAGE_SIZE). But that makes it difficult to kfree() when garbage
collector is added. Thus, remove memory pool and use kmalloc(sizeof()).
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
Currently, TOMOYO allocates memory for string data from memory pool allocated
by kmalloc(PAGE_SIZE). But that makes it difficult to kfree() when garbage
collector is added. Thus, remove memory pool and use kmalloc(strlen()).
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
Since readers no longer use down_read(), writers no longer
need to use rw_semaphore. Replace individual rw_semaphore by
single mutex.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Don't pass current RLIMIT_RTTIME to update_rlimit_cpu() in
selinux_bprm_committing_creds, since update_rlimit_cpu expects
RLIMIT_CPU limit.
Use proper rlim[RLIMIT_CPU].rlim_cur instead to fix that.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Acked-by: James Morris <jmorris@namei.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Eric Paris <eparis@parisplace.org>
Cc: David Howells <dhowells@redhat.com>
* pull ACC_MODE to fs.h; we have several copies all over the place
* nightmarish expression calculating f_mode by f_flags deserves a helper
too (OPEN_FMODE(flags))
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
As of commit ee18d64c1f ("KEYS: Add a keyctl to
install a process's session keyring on its parent [try #6]"), CONFIG_KEYS=y
fails to build on architectures that haven't implemented TIF_NOTIFY_RESUME yet:
security/keys/keyctl.c: In function 'keyctl_session_to_parent':
security/keys/keyctl.c:1312: error: 'TIF_NOTIFY_RESUME' undeclared (first use in this function)
security/keys/keyctl.c:1312: error: (Each undeclared identifier is reported only once
security/keys/keyctl.c:1312: error: for each function it appears in.)
Make KEYCTL_SESSION_TO_PARENT depend on TIF_NOTIFY_RESUME until
m68k, and xtensa have implemented it.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
In NOMMU mode clamp dac_mmap_min_addr to zero to cause the tests on it to be
skipped by the compiler. We do this as the minimum mmap address doesn't make
any sense in NOMMU mode.
mmap_min_addr and round_hint_to_min() can be discarded entirely in NOMMU mode.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
init_mmap_min_addr() is a pure_initcall and should be static.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <jmorris@namei.org>
Return the PTR_ERR of the correct pointer.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Limit the number of imbalance messages to once per filesystem type instead of
once per system boot. (it's actually slightly racy and could give you a
couple per fs, but this isn't a real issue)
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Kill the 'update' argument of ima_path_check(), kill
dead code in ima.
Current rules: ima counters are bumped at the same time
when the file switches from put_filp() fodder to fput()
one. Which happens exactly in two places - alloc_file()
and __dentry_open(). Nothing else needs to do that at
all.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
ima_inode_free() has some funky #define just to confuse the crap out of me.
void ima_iint_delete(struct inode *inode)
and then things actually call ima_inode_free() and nothing calls
ima_iint_delete().
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We currently have a lot of duplicated code around ima file counts. Clean
that all up.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
iints are supposed to be allocated when an inode is allocated (during
security_inode_alloc()) But we have code which will attempt to allocate
an iint during measurement calls. If we couldn't allocate the iint and we
cared, we should have died during security_inode_alloc(). Not make the
code more complex and less efficient.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
ima_inode_alloc returns 0 and 1, but the LSM hooks expects an errno.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Replace list operation with RCU primitives and replace
down_read()/up_read() with srcu_read_lock()/srcu_read_unlock().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Please apply below one after merging 1557d33007
(Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl-2.6).
----------
[PATCH for 2.6.33] TOMOYO: Compare filesystem by magic number rather than by name.
We can use magic number for checking whether the filesystem is procfs or not.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1815 commits)
mac80211: fix reorder buffer release
iwmc3200wifi: Enable wimax core through module parameter
iwmc3200wifi: Add wifi-wimax coexistence mode as a module parameter
iwmc3200wifi: Coex table command does not expect a response
iwmc3200wifi: Update wiwi priority table
iwlwifi: driver version track kernel version
iwlwifi: indicate uCode type when fail dump error/event log
iwl3945: remove duplicated event logging code
b43: fix two warnings
ipw2100: fix rebooting hang with driver loaded
cfg80211: indent regulatory messages with spaces
iwmc3200wifi: fix NULL pointer dereference in pmkid update
mac80211: Fix TX status reporting for injected data frames
ath9k: enable 2GHz band only if the device supports it
airo: Fix integer overflow warning
rt2x00: Fix padding bug on L2PAD devices.
WE: Fix set events not propagated
b43legacy: avoid PPC fault during resume
b43: avoid PPC fault during resume
tcp: fix a timewait refcnt race
...
Fix up conflicts due to sysctl cleanups (dead sysctl_check code and
CTL_UNNUMBERED removed) in
kernel/sysctl_check.c
net/ipv4/sysctl_net_ipv4.c
net/ipv6/addrconf.c
net/sctp/sysctl.c
* git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl-2.6: (43 commits)
security/tomoyo: Remove now unnecessary handling of security_sysctl.
security/tomoyo: Add a special case to handle accesses through the internal proc mount.
sysctl: Drop & in front of every proc_handler.
sysctl: Remove CTL_NONE and CTL_UNNUMBERED
sysctl: kill dead ctl_handler definitions.
sysctl: Remove the last of the generic binary sysctl support
sysctl net: Remove unused binary sysctl code
sysctl security/tomoyo: Don't look at ctl_name
sysctl arm: Remove binary sysctl support
sysctl x86: Remove dead binary sysctl support
sysctl sh: Remove dead binary sysctl support
sysctl powerpc: Remove dead binary sysctl support
sysctl ia64: Remove dead binary sysctl support
sysctl s390: Remove dead sysctl binary support
sysctl frv: Remove dead binary sysctl support
sysctl mips/lasat: Remove dead binary sysctl support
sysctl drivers: Remove dead binary sysctl support
sysctl crypto: Remove dead binary sysctl support
sysctl security/keys: Remove dead binary sysctl support
sysctl kernel: Remove binary sysctl logic
...
The last return is unreachable, remove the 'return'
in default, let it fall through.
Signed-off-by: WANG Cong <amwang@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
LSM hooks for chmod()/chown()/chroot() are now ready.
This patch utilizes these hooks.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
include/linux/security.h and security/capability.c are using "struct path *dir"
but security/security.c was using "struct path *path" by error.
This patch renames "struct path *path" to "struct path *dir".
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
The size argument to kcalloc should be the size of desired structure,
not the pointer to it.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@expression@
expression *x;
@@
x =
<+...
-sizeof(x)
+sizeof(*x)
...+>// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
TOMOYO 1.7.1 has recursive directory matching operator support.
I want to add it to TOMOYO for Linux 2.6.33 .
----------
[PATCH] TOMOYO: Add recursive directory matching operator support.
This patch introduces new operator /\{dir\}/ which matches
'/' + 'One or more repetitions of dir/' (e.g. /dir/ /dir/dir/ /dir/dir/dir/ ).
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
As far as I know, all distros currently ship kernels with default
CONFIG_SECURITY_FILE_CAPABILITIES=y. Since having the option on
leaves a 'no_file_caps' option to boot without file capabilities,
the main reason to keep the option is that turning it off saves
you (on my s390x partition) 5k. In particular, vmlinux sizes
came to:
without patch fscaps=n: 53598392
without patch fscaps=y: 53603406
with this patch applied: 53603342
with the security-next tree.
Against this we must weigh the fact that there is no simple way for
userspace to figure out whether file capabilities are supported,
while things like per-process securebits, capability bounding
sets, and adding bits to pI if CAP_SETPCAP is in pE are not supported
with SECURITY_FILE_CAPABILITIES=n, leaving a bit of a problem for
applications wanting to know whether they can use them and/or why
something failed.
It also adds another subtly different set of semantics which we must
maintain at the risk of severe security regressions.
So this patch removes the SECURITY_FILE_CAPABILITIES compile
option. It drops the kernel size by about 50k over the stock
SECURITY_FILE_CAPABILITIES=y kernel, by removing the
cap_limit_ptraced_target() function.
Changelog:
Nov 20: remove cap_limit_ptraced_target() as it's logic
was ifndef'ed.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Andrew G. Morgan" <morgan@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
Historically we've seen cases where permissions are requested for classes
where they do not exist. In particular we have seen CIFS forget to set
i_mode to indicate it is a directory so when we later check something like
remove_name we have problems since it wasn't defined in tclass file. This
used to result in a avc which included the permission 0x2000 or something.
Currently the kernel will deny the operations (good thing) but will not
print ANY information (bad thing). First the auditdeny field is no
extended to include unknown permissions. After that is fixed the logic in
avc_dump_query to output this information isn't right since it will remove
the permission from the av and print the phrase "<NULL>". This takes us
back to the behavior before the classmap rewrite.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Now that sys_sysctl is an emulation on top of proc sys all sysctl
operations look like normal filesystem operations and we don't need
to use the special sysctl hook to authenticate them.
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
With the change of sys_sysctl going through the internal proc mount we no
longer need to handle security_sysctl in tomoyo as we have valid pathnames
for all sysctl accesses. There is one slight caveat to that in that
all of the paths from the internal mount look like
"/sys/net/ipv4/ip_local_port_range" instead of
"/proc/sys/net/ipv4/ip_local_port_range" so tomoyo needs to add the
"/proc" portion manually when resolving to full path names to get what it expects.
This change teaches tomoyo perform that modification.
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
While running fsstress tests on the NFSv4 mounted ext3 and ext4
filesystem, the following call trace was generated on the nfs
server machine.
Replace GFP_KERNEL with GFP_NOFS in ima_iint_insert() to avoid a
potential deadlock.
=================================
[ INFO: inconsistent lock state ]
2.6.31-31.el6.x86_64 #1
---------------------------------
inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd2/75 [HC0[0]:SC0[0]:HE1:SE1] takes:
(jbd2_handle){+.+.?.}, at: [<ffffffff811edd5e>] jbd2_journal_start+0xfe/0x13f
{RECLAIM_FS-ON-W} state was registered at:
[<ffffffff81091e40>] mark_held_locks+0x65/0x99
[<ffffffff81091f31>] lockdep_trace_alloc+0xbd/0xf5
[<ffffffff81126fdd>] kmem_cache_alloc+0x40/0x185
[<ffffffff812344d7>] ima_iint_insert+0x3d/0xf1
[<ffffffff812345b0>] ima_inode_alloc+0x25/0x44
[<ffffffff811484ac>] inode_init_always+0xec/0x271
[<ffffffff81148682>] alloc_inode+0x51/0xa1
[<ffffffff81148700>] new_inode+0x2e/0x94
[<ffffffff811b2f08>] ext4_new_inode+0xb8/0xdc9
[<ffffffff811be611>] ext4_create+0xcf/0x175
[<ffffffff8113e2cd>] vfs_create+0x82/0xb8
[<ffffffff8113f337>] do_filp_open+0x32c/0x9ee
[<ffffffff811309b9>] do_sys_open+0x6c/0x12c
[<ffffffff81130adc>] sys_open+0x2e/0x44
[<ffffffff81011e42>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 90371
hardirqs last enabled at (90371): [<ffffffff8112708d>]
kmem_cache_alloc+0xf0/0x185
hardirqs last disabled at (90370): [<ffffffff81127026>]
kmem_cache_alloc+0x89/0x185
softirqs last enabled at (89492): [<ffffffff81068ecf>]
__do_softirq+0x1bf/0x1eb
softirqs last disabled at (89477): [<ffffffff8101312c>] call_softirq+0x1c/0x30
other info that might help us debug this:
2 locks held by kswapd2/75:
#0: (shrinker_rwsem){++++..}, at: [<ffffffff810f98ba>] shrink_slab+0x44/0x177
#1: (&type->s_umount_key#25){++++..}, at: [<ffffffff811450ba>]
Reported-by: Muni P. Beerakam <mbeeraka@in.ibm.com>
Reported-by: Amit K. Arora <amitarora@in.ibm.com>
Cc: stable@kernel.org
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
For consistency drop & in front of every proc_handler. Explicity
taking the address is unnecessary and it prevents optimizations
like stubbing the proc_handlers to NULL.
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
ctl_name field was removed. Always use procname field.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Now that sys_sysctl is a generic wrapper around /proc/sys .ctl_name
and .strategy members of sysctl tables are dead code. Remove them.
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
For SELinux to do better filtering in userspace we send the name of the
module along with the AVC denial when a program is denied module_request.
Example output:
type=SYSCALL msg=audit(11/03/2009 10:59:43.510:9) : arch=x86_64 syscall=write success=yes exit=2 a0=3 a1=7fc28c0d56c0 a2=2 a3=7fffca0d7440 items=0 ppid=1727 pid=1729 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=rpc.nfsd exe=/usr/sbin/rpc.nfsd subj=system_u:system_r:nfsd_t:s0 key=(null)
type=AVC msg=audit(11/03/2009 10:59:43.510:9) : avc: denied { module_request } for pid=1729 comm=rpc.nfsd kmod="net-pf-10" scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=system
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
The LSM currently requires setting a kernel parameter at boot to select
a specific LSM. This adds a config option that allows specifying a default
LSM that is used unless overridden with the security= kernel parameter.
If the the config option is not set the current behavior of first LSM
to register is used.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Currently the mmap_min_addr value can only be bypassed during mmap when
the task has CAP_SYS_RAWIO. However, the mmap_min_addr sysctl value itself
can be adjusted to 0 if euid == 0, allowing a bypass without CAP_SYS_RAWIO.
This patch adds a check for the capability before allowing mmap_min_addr to
be changed.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
When examining the network device name hash, it was discovered that
the low order bits of full_name_hash() are not very well dispersed
across the possible values. When used by filesystem code, this is handled
by folding with the function hash_long().
The only other non-filesystem usage of full_name_hash() at this time
appears to be in TOMOYO. This patch should fix that.
I do not use TOMOYO at this time, so this patch is build tested only.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
Based on discussions on LKML and LSM, where there are consecutive
security_ and ima_ calls in the vfs layer, move the ima_ calls to
the existing security_ hooks.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
The SELinux dynamic class work in c6d3aaa4e3
creates a number of dynamic header files and scripts. Add .gitignore files
so git doesn't complain about these.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Remove the root_plug example LSM code. It's unmaintained and
increasingly broken in various ways.
Made at the 2009 Kernel Summit in Tokyo!
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: James Morris <jmorris@namei.org>
Ensure that we release the policy read lock on all exit paths from
security_compute_av.
Signed-off-by: Stephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
In order to have better cache layouts of struct sock (separate zones
for rx/tx paths), we need this preliminary patch.
Goal is to transfert fields used at lookup time in the first
read-mostly cache line (inside struct sock_common) and move sk_refcnt
to a separate cache line (only written by rx path)
This patch adds inet_ prefix to daddr, rcv_saddr, dport, num, saddr,
sport and id fields. This allows a future patch to define these
fields as macros, like sk_refcnt, without name clashes.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The destination keyring specified to request_key() and co. is made available to
the process that instantiates the key (the slave process started by
/sbin/request-key typically). This is passed in the request_key_auth struct as
the dest_keyring member.
keyctl_instantiate_key and keyctl_negate_key() call get_instantiation_keyring()
to get the keyring to attach the newly constructed key to at the end of
instantiation. This may be given a specific keyring into which a link will be
made later, or it may be asked to find the keyring passed to request_key(). In
the former case, it returns a keyring with the refcount incremented by
lookup_user_key(); in the latter case, it returns the keyring from the
request_key_auth struct - and does _not_ increment the refcount.
The latter case will eventually result in an oops when the keyring prematurely
runs out of references and gets destroyed. The effect may take some time to
show up as the key is destroyed lazily.
To fix this, the keyring returned by get_instantiation_keyring() must always
have its refcount incremented, no matter where it comes from.
This can be tested by setting /etc/request-key.conf to:
#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ...
#====== ======= =============== =============== ===============================
create * test:* * |/bin/false %u %g %d %{user:_display}
negate * * * /bin/keyctl negate %k 10 @u
and then doing:
keyctl add user _display aaaaaaaa @u
while keyctl request2 user test:x test:x @u &&
keyctl list @u;
do
keyctl request2 user test:x test:x @u;
sleep 31;
keyctl list @u;
done
which will oops eventually. Changing the negate line to have @u rather than
%S at the end is important as that forces the latter case by passing a special
keyring ID rather than an actual keyring ID.
Reported-by: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch allows pathname based LSM modules to check chroot() operations.
This hook is used by TOMOYO.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
This patch allows pathname based LSM modules to check chmod()/chown()
operations. Since notify_change() does not receive "struct vfsmount *",
we add security_path_chmod() and security_path_chown() to the caller of
notify_change().
These hooks are used by TOMOYO.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
Drop remapping of netlink classes and bypass of permission checking
based on netlink message type for policy version < 18. This removes
compatibility code introduced when the original single netlink
security class used for all netlink sockets was split into
finer-grained netlink classes based on netlink protocol and when
permission checking was added based on netlink message type in Linux
2.6.8. The only known distribution that shipped with SELinux and
policy < 18 was Fedora Core 2, which was EOL'd on 2005-04-11.
Given that the remapping code was never updated to address the
addition of newer netlink classes, that the corresponding userland
support was dropped in 2005, and that the assumptions made by the
remapping code about the fixed ordering among netlink classes in the
policy may be violated in the future due to the dynamic class/perm
discovery support, we should drop this compatibility code now.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Add a simple utility (scripts/selinux/genheaders) and invoke it to
generate the kernel-private class and permission indices in flask.h
and av_permissions.h automatically during the kernel build from the
security class mapping definitions in classmap.h. Adding new kernel
classes and permissions can then be done just by adding them to classmap.h.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Modify SELinux to dynamically discover class and permission values
upon policy load, based on the dynamic object class/perm discovery
logic from libselinux. A mapping is created between kernel-private
class and permission indices used outside the security server and the
policy values used within the security server.
The mappings are only applied upon kernel-internal computations;
similar mappings for the private indices of userspace object managers
is handled on a per-object manager basis by the userspace AVC. The
interfaces for compute_av and transition_sid are split for kernel
vs. userspace; the userspace functions are distinguished by a _user
suffix.
The kernel-private class indices are no longer tied to the policy
values and thus do not need to skip indices for userspace classes;
thus the kernel class index values are compressed. The flask.h
definitions were regenerated by deleting the userspace classes from
refpolicy's definitions and then regenerating the headers. Going
forward, we can just maintain the flask.h, av_permissions.h, and
classmap.h definitions separately from policy as they are no longer
tied to the policy values. The next patch introduces a utility to
automate generation of flask.h and av_permissions.h from the
classmap.h definitions.
The older kernel class and permission string tables are removed and
replaced by a single security class mapping table that is walked at
policy load to generate the mapping. The old kernel class validation
logic is completely replaced by the mapping logic.
The handle unknown logic is reworked. reject_unknown=1 is handled
when the mappings are computed at policy load time, similar to the old
handling by the class validation logic. allow_unknown=1 is handled
when computing and mapping decisions - if the permission was not able
to be mapped (i.e. undefined, mapped to zero), then it is
automatically added to the allowed vector. If the class was not able
to be mapped (i.e. undefined, mapped to zero), then all permissions
are allowed for it if allow_unknown=1.
avc_audit leverages the new security class mapping table to lookup the
class and permission names from the kernel-private indices.
The mdp program is updated to use the new table when generating the
class definitions and allow rules for a minimal boot policy for the
kernel. It should be noted that this policy will not include any
userspace classes, nor will its policy index values for the kernel
classes correspond with the ones in refpolicy (they will instead match
the kernel-private indices).
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
This patch resets the security_ops to the secondary_ops before it flushes
the avc. It's still possible that a task on another processor could have
already passed the security_ops dereference and be executing an selinux hook
function which would add a new avc entry. That entry would still not be
freed. This should however help to reduce the number of needless avcs the
kernel has when selinux is disabled at run time. There is no wasted
memory if selinux is disabled on the command line or not compiled.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current:
lsm: Use a compressed IPv6 string format in audit events
Audit: send signal info if selinux is disabled
Audit: rearrange audit_context to save 16 bytes per struct
Audit: reorganize struct audit_watch to save 8 bytes
It's unused.
It isn't needed -- read or write flag is already passed and sysctl
shouldn't care about the rest.
It _was_ used in two places at arch/frv for some reason.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ratan Nalumasu reported that in a process with many threads doing
unnecessary wakeups. Every waiting thread in the process wakes up to loop
through the children and see that the only ones it cares about are still
not ready.
Now that we have struct wait_opts we can change do_wait/__wake_up_parent
to use filtered wakeups.
We can make child_wait_callback() more clever later, right now it only
checks eligible_child().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ratan Nalumasu <rnalumasu@gmail.com>
Cc: Vitaly Mayatskikh <vmayatsk@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Tested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alter the ss->can_attach and ss->attach functions to be able to deal with
a whole threadgroup at a time, for use in cgroup_attach_proc. (This is a
pre-patch to cgroup-procs-writable.patch.)
Currently, new mode of the attach function can only tell the subsystem
about the old cgroup of the threadgroup leader. No subsystem currently
needs that information for each thread that's being moved, but if one were
to be added (for example, one that counts tasks within a group) this bit
would need to be reworked a bit to tell the subsystem the right
information.
[hidave.darkstar@gmail.com: fix build]
Signed-off-by: Ben Blum <bblum@google.com>
Signed-off-by: Paul Menage <menage@google.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the audit subsystem prints uncompressed IPv6 addresses which not
only differs from common usage but also results in ridiculously large audit
strings which is not a good thing. This patch fixes this by simply converting
audit to always print compressed IPv6 addresses.
Old message example:
audit(1253576792.161:30): avc: denied { ingress } for
saddr=0000:0000:0000:0000:0000:0000:0000:0001 src=5000
daddr=0000:0000:0000:0000:0000:0000:0000:0001 dest=35502 netif=lo
scontext=system_u:object_r:unlabeled_t:s15:c0.c1023
tcontext=system_u:object_r:lo_netif_t:s0-s15:c0.c1023 tclass=netif
New message example:
audit(1253576792.161:30): avc: denied { ingress } for
saddr=::1 src=5000 daddr=::1 dest=35502 netif=lo
scontext=system_u:object_r:unlabeled_t:s15:c0.c1023
tcontext=system_u:object_r:lo_netif_t:s0-s15:c0.c1023 tclass=netif
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
SELinux: do not destroy the avc_cache_nodep
KEYS: Have the garbage collector set its timer for live expired keys
tpm-fixup-pcrs-sysfs-file-update
creds_are_invalid() needs to be exported for use by modules:
include/linux/cred.h: fix build
Fix trivial BUILD_BUG_ON-induced conflicts in drivers/char/tpm/tpm.c
The key garbage collector sets a timer to start a new collection cycle at the
point the earliest key to expire should be considered garbage. However, it
currently only does this if the key it is considering hasn't yet expired.
If the key being considering has expired, but hasn't yet reached the collection
time then it is ignored, and won't be collected until some other key provokes a
round of collection.
Make the garbage collector set the timer for the earliest key that hasn't yet
passed its collection time, rather than the earliest key that hasn't yet
expired.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Make all seq_operations structs const, to help mitigate against
revectoring user-triggerable function pointers.
This is derived from the grsecurity patch, although generated from scratch
because it's simpler than extracting the changes from there.
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move various magic-number definitions into magic.h.
Signed-off-by: Nick Black <dank@qemfd.net>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-txt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, intel_txt: clean up the impact on generic code, unbreak non-x86
x86, intel_txt: Handle ACPI_SLEEP without X86_TRAMPOLINE
x86, intel_txt: Fix typos in Kconfig help
x86, intel_txt: Factor out the code for S3 setup
x86, intel_txt: tboot.c needs <asm/fixmap.h>
intel_txt: Force IOMMU on for Intel TXT launch
x86, intel_txt: Intel TXT Sx shutdown support
x86, intel_txt: Intel TXT reboot/halt shutdown support
x86, intel_txt: Intel TXT boot support
Fix a number of problems with the new key garbage collector:
(1) A rogue semicolon in keyring_gc() was causing the initial count of dead
keys to be miscalculated.
(2) A missing return in keyring_gc() meant that under certain circumstances,
the keyring semaphore would be unlocked twice.
(3) The key serial tree iterator (key_garbage_collector()) part of the garbage
collector has been modified to:
(a) Complete each scan of the keyrings before setting the new timer.
(b) Only set the new timer for keys that have yet to expire. This means
that the new timer is now calculated correctly, and the gc doesn't
get into a loop continually scanning for keys that have expired, and
preventing other things from happening, like RCU cleaning up the old
keyring contents.
(c) Perform an extra scan if any keys were garbage collected in this one
as a key might become garbage during a scan, and (b) could mean we
don't set the timer again.
(4) Made key_schedule_gc() take the time at which to do a collection run,
rather than the time at which the key expires. This means the collection
of dead keys (key type unregistered) can happen immediately.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
When we exit early from keyctl_session_to_parent because of permissions or
because the session keyring is the same as the parent, we need to unlock the
tasklist.
The missing unlock causes the system to hang completely when using
keyctl(KEYCTL_SESSION_TO_PARENT) with a keyring shared with the parent.
Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Before SELinux is disabled at boot it can create AVC entries. This patch
will flush those entries before disabling SELinux.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Move the avc_cache flushing into it's own function so it can be reused when
disabling SELinux.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
__validate_process_creds should check if selinux is actually enabled before
running tests on the selinux portion of the credentials struct.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This patch adds a setxattr handler to the file, directory, and symlink
inode_operations structures for sysfs. The patch uses hooks introduced in the
previous patch to handle the getting and setting of security information for
the sysfs inodes. As was suggested by Eric Biederman the struct iattr in the
sysfs_dirent structure has been replaced by a structure which contains the
iattr, secdata and secdata length to allow the changes to persist in the event
that the inode representing the sysfs_dirent is evicted. Because sysfs only
stores this information when a change is made all the optional data is moved
into one dynamically allocated field.
This patch addresses an issue where SELinux was denying virtd access to the PCI
configuration entries in sysfs. The lack of setxattr handlers for sysfs
required that a single label be assigned to all entries in sysfs. Granting virtd
access to every entry in sysfs is not an acceptable solution so fine grained
labeling of sysfs is required such that individual entries can be labeled
appropriately.
[sds: Fixed compile-time warnings, coding style, and setting of inode security init flags.]
Signed-off-by: David P. Quigley <dpquigl@tycho.nsa.gov>
Signed-off-by: Stephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
This patch introduces three new hooks. The inode_getsecctx hook is used to get
all relevant information from an LSM about an inode. The inode_setsecctx is
used to set both the in-core and on-disk state for the inode based on a context
derived from inode_getsecctx.The final hook inode_notifysecctx will notify the
LSM of a change for the in-core state of the inode in question. These hooks are
for use in the labeled NFS code and addresses concerns of how to set security
on an inode in a multi-xattr LSM. For historical reasons Stephen Smalley's
explanation of the reason for these hooks is pasted below.
Quote Stephen Smalley
inode_setsecctx: Change the security context of an inode. Updates the
in core security context managed by the security module and invokes the
fs code as needed (via __vfs_setxattr_noperm) to update any backing
xattrs that represent the context. Example usage: NFS server invokes
this hook to change the security context in its incore inode and on the
backing file system to a value provided by the client on a SETATTR
operation.
inode_notifysecctx: Notify the security module of what the security
context of an inode should be. Initializes the incore security context
managed by the security module for this inode. Example usage: NFS
client invokes this hook to initialize the security context in its
incore inode to the value provided by the server for the file when the
server returned the file's attributes to the client.
Signed-off-by: David P. Quigley <dpquigl@tycho.nsa.gov>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
- As ima_counts_put() may be called after the inode has been freed,
verify that the inode is not NULL, before dereferencing it.
- Maintain the IMA file counters in may_open() properly, decrementing
any counter increments on subsequent errors.
Reported-by: Ciprian Docan <docan@eden.rutgers.edu>
Reported-by: J.R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Eric Paris <eparis@redhat.com
Signed-off-by: James Morris <jmorris@namei.org>
Add a keyctl to install a process's session keyring onto its parent. This
replaces the parent's session keyring. Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again. Normally this
will be after a wait*() syscall.
To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.
The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.
Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the
replacement to be performed at the point the parent process resumes userspace
execution.
This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership. However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.
This can be tested with the following program:
#include <stdio.h>
#include <stdlib.h>
#include <keyutils.h>
#define KEYCTL_SESSION_TO_PARENT 18
#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)
int main(int argc, char **argv)
{
key_serial_t keyring, key;
long ret;
keyring = keyctl_join_session_keyring(argv[1]);
OSERROR(keyring, "keyctl_join_session_keyring");
key = add_key("user", "a", "b", 1, keyring);
OSERROR(key, "add_key");
ret = keyctl(KEYCTL_SESSION_TO_PARENT);
OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");
return 0;
}
Compiled and linked with -lkeyutils, you should see something like:
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
355907932 --alswrv 4043 -1 \_ keyring: _uid.4043
[dhowells@andromeda ~]$ /tmp/newpag
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
1055658746 --alswrv 4043 4043 \_ user: a
[dhowells@andromeda ~]$ /tmp/newpag hello
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: hello
340417692 --alswrv 4043 4043 \_ user: a
Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Do some whitespace cleanups in the key management code.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Make the file position maintained by /proc/keys represent the ID of the key
just read rather than the number of keys read. This should make it faster to
perform a lookup as we don't have to scan the key ID tree from the beginning to
find the current position.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Add garbage collection for dead, revoked and expired keys. This involved
erasing all links to such keys from keyrings that point to them. At that
point, the key will be deleted in the normal manner.
Keyrings from which garbage collection occurs are shrunk and their quota
consumption reduced as appropriate.
Dead keys (for which the key type has been removed) will be garbage collected
immediately.
Revoked and expired keys will hang around for a number of seconds, as set in
/proc/sys/kernel/keys/gc_delay before being automatically removed. The default
is 5 minutes.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Set the KEY_FLAG_DEAD flag on keys for which the type has been removed. This
causes the key_permission() function to return EKEYREVOKED in response to
various commands. It does not, however, prevent unlinking or clearing of
keyrings from detaching the key.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Allow keyctl_revoke() to operate on keys that have SETATTR but not WRITE
permission, rather than only on keys that have WRITE permission.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Allow keys for which the key type has been removed to be unlinked. Currently
dead-type keys can only be disposed of by completely clearing the keyrings
that point to them.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Add a config option (CONFIG_DEBUG_CREDENTIALS) to turn on some debug checking
for credential management. The additional code keeps track of the number of
pointers from task_structs to any given cred struct, and checks to see that
this number never exceeds the usage count of the cred struct (which includes
all references, not just those from task_structs).
Furthermore, if SELinux is enabled, the code also checks that the security
pointer in the cred struct is never seen to be invalid.
This attempts to catch the bug whereby inode_has_perm() faults in an nfsd
kernel thread on seeing cred->security be a NULL pointer (it appears that the
credential struct has been previously released):
http://www.kerneloops.org/oops.php?number=252883
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Conflicts:
arch/x86/kernel/reboot.c
security/Kconfig
Merge reason: resolve the conflicts, bump up from rc3 to rc8.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move tboot.h from asm to linux to fix the build errors of intel_txt
patch on non-X86 platforms. Remove the tboot code from generic code
init/main.c and kernel/cpu.c.
Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Add support for the new TUN LSM hooks: security_tun_dev_create(),
security_tun_dev_post_create() and security_tun_dev_attach(). This includes
the addition of a new object class, tun_socket, which represents the socks
associated with TUN devices. The _tun_dev_create() and _tun_dev_post_create()
hooks are fairly similar to the standard socket functions but _tun_dev_attach()
is a bit special. The _tun_dev_attach() is unique because it involves a
domain attaching to an existing TUN device and its associated tun_socket
object, an operation which does not exist with standard sockets and most
closely resembles a relabel operation.
Signed-off-by: Paul Moore <paul.moore@hp.com>
Acked-by: Eric Paris <eparis@parisplace.org>
Signed-off-by: James Morris <jmorris@namei.org>
The TUN driver lacks any LSM hooks which makes it difficult for LSM modules,
such as SELinux, to enforce access controls on network traffic generated by
TUN users; this is particularly problematic for virtualization apps such as
QEMU and KVM. This patch adds three new LSM hooks designed to control the
creation and attachment of TUN devices, the hooks are:
* security_tun_dev_create()
Provides access control for the creation of new TUN devices
* security_tun_dev_post_create()
Provides the ability to create the necessary socket LSM state for newly
created TUN devices
* security_tun_dev_attach()
Provides access control for attaching to existing, persistent TUN devices
and the ability to update the TUN device's socket LSM state as necessary
Signed-off-by: Paul Moore <paul.moore@hp.com>
Acked-by: Eric Paris <eparis@parisplace.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Morris <jmorris@namei.org>
ima_counts_get() calls ima_iint_find_insert_get() which takes a reference
to the iint in question, but does not put that reference at the end of the
function. This can lead to a nasty memory leak. Easy enough to reproduce:
#include <sys/mman.h>
#include <stdio.h>
int main (void)
{
int i;
void *ptr;
for (i=0; i < 100000; i++) {
ptr = mmap(NULL, 4096, PROT_READ|PROT_WRITE,
MAP_SHARED|MAP_ANONYMOUS, -1, 0);
if (ptr == MAP_FAILED)
return 2;
munmap(ptr, 4096);
}
return 0;
}
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Hashing files larger than INT_MAX causes process to loop.
Dependent on redefining kernel_read() offset type to loff_t.
(http://bugzilla.kernel.org/show_bug.cgi?id=13909)
Cc: stable@kernel.org
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
As suggested by OGAWA Hirofumi in thread:
http://lkml.org/lkml/2009/8/7/132, we should let selinux_inode_setattr()
to match our ATTR_* rules. ATTR_FORCE should not force things like
ATTR_SIZE.
[hirofumi@mail.parknet.co.jp: tweaks]
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@redhat.com>
Cc: Eugene Teo <eteo@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <jmorris@namei.org>
Fix prompt for LSM_MMAP_MIN_ADDR.
(Verbs are cool!)
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Commit 788084aba2 added the LSM_MMAP_MIN_ADDR
option, whose help text states "For most ia64, ppc64 and x86 users with lots
of address space a value of 65536 is reasonable and should cause no problems."
Which implies that it's default setting was typoed.
Signed-off-by: Dave Jones <davej@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Currently SELinux enforcement of controls on the ability to map low memory
is determined by the mmap_min_addr tunable. This patch causes SELinux to
ignore the tunable and instead use a seperate Kconfig option specific to how
much space the LSM should protect.
The tunable will now only control the need for CAP_SYS_RAWIO and SELinux
permissions will always protect the amount of low memory designated by
CONFIG_LSM_MMAP_MIN_ADDR.
This allows users who need to disable the mmap_min_addr controls (usual reason
being they run WINE as a non-root user) to do so and still have SELinux
controls preventing confined domains (like a web server) from being able to
map some area of low memory.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Currently SELinux does not check CAP_SYS_RAWIO in the file_mmap hook. This
means there is no DAC check on the ability to mmap low addresses in the
memory space. This function adds the DAC check for CAP_SYS_RAWIO while
maintaining the selinux check on mmap_zero. This means that processes
which need to mmap low memory will need CAP_SYS_RAWIO and mmap_zero but will
NOT need the SELinux sys_rawio capability.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Currently we duplicate the mmap_min_addr test in cap_file_mmap and in
security_file_mmap if !CONFIG_SECURITY. This patch moves cap_file_mmap
into commoncap.c and then calls that function directly from
security_file_mmap ifndef CONFIG_SECURITY like all of the other capability
checks are done.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Convert avc_audit in security/selinux/avc.c to use lsm_audit.h,
for better maintainability.
- changed selinux to use common_audit_data instead of
avc_audit_data
- eliminated code in avc.c and used code from lsm_audit.h instead.
Had to add a LSM_AUDIT_NO_AUDIT to lsm_audit.h so that avc_audit
can call common_lsm_audit and do the pre and post callbacks without
doing the actual dump. This makes it so that the patched version
behaves the same way as the unpatched version.
Also added a denied field to the selinux_audit_data private space,
once again to make it so that the patched version behaves like the
unpatched.
I've tested and confirmed that AVCs look the same before and after
this patch.
Signed-off-by: Thomas Liu <tliu@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
This patch adds a new selinux hook so SELinux can arbitrate if a given
process should be allowed to trigger a request for the kernel to try to
load a module. This is a different operation than a process trying to load
a module itself, which is already protected by CAP_SYS_MODULE.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Calling request_module() will trigger a userspace upcall which will load a
new module into the kernel. This can be a dangerous event if the process
able to trigger request_module() is able to control either the modprobe
binary or the module binary. This patch adds a new security hook to
request_module() which can be used by an LSM to control a processes ability
to call request_module().
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Fix memory leakage in /security/selinux/hooks.c
The buffer always needs to be freed here; we either error
out or allocate more memory.
Reported-by: iceberg <strakh@ispras.ru>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Currently SELinux enforcement of controls on the ability to map low memory
is determined by the mmap_min_addr tunable. This patch causes SELinux to
ignore the tunable and instead use a seperate Kconfig option specific to how
much space the LSM should protect.
The tunable will now only control the need for CAP_SYS_RAWIO and SELinux
permissions will always protect the amount of low memory designated by
CONFIG_LSM_MMAP_MIN_ADDR.
This allows users who need to disable the mmap_min_addr controls (usual reason
being they run WINE as a non-root user) to do so and still have SELinux
controls preventing confined domains (like a web server) from being able to
map some area of low memory.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Currently SELinux does not check CAP_SYS_RAWIO in the file_mmap hook. This
means there is no DAC check on the ability to mmap low addresses in the
memory space. This function adds the DAC check for CAP_SYS_RAWIO while
maintaining the selinux check on mmap_zero. This means that processes
which need to mmap low memory will need CAP_SYS_RAWIO and mmap_zero but will
NOT need the SELinux sys_rawio capability.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Currently we duplicate the mmap_min_addr test in cap_file_mmap and in
security_file_mmap if !CONFIG_SECURITY. This patch moves cap_file_mmap
into commoncap.c and then calls that function directly from
security_file_mmap ifndef CONFIG_SECURITY like all of the other capability
checks are done.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Elsewhere the sin_family field holds a value with a name of the form
AF_..., so it seems reasonable to do so here as well. Also the values of
PF_INET and AF_INET are the same.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
struct sockaddr_in sip;
@@
(
sip.sin_family ==
- PF_INET
+ AF_INET
|
sip.sin_family !=
- PF_INET
+ AF_INET
|
sip.sin_family =
- PF_INET
+ AF_INET
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: James Morris <jmorris@namei.org>
This patch adds kernel configuration and boot support for Intel Trusted
Execution Technology (Intel TXT).
Intel's technology for safer computing, Intel Trusted Execution
Technology (Intel TXT), defines platform-level enhancements that
provide the building blocks for creating trusted platforms.
Intel TXT was formerly known by the code name LaGrande Technology (LT).
Intel TXT in Brief:
o Provides dynamic root of trust for measurement (DRTM)
o Data protection in case of improper shutdown
o Measurement and verification of launched environment
Intel TXT is part of the vPro(TM) brand and is also available some
non-vPro systems. It is currently available on desktop systems based on
the Q35, X38, Q45, and Q43 Express chipsets (e.g. Dell Optiplex 755, HP
dc7800, etc.) and mobile systems based on the GM45, PM45, and GS45
Express chipsets.
For more information, see http://www.intel.com/technology/security/.
This site also has a link to the Intel TXT MLE Developers Manual, which
has been updated for the new released platforms.
A much more complete description of how these patches support TXT, how to
configure a system for it, etc. is in the Documentation/intel_txt.txt file
in this patch.
This patch provides the TXT support routines for complete functionality,
documentation for TXT support and for the changes to the boot_params structure,
and boot detection of a TXT launch. Attempts to shutdown (reboot, Sx) the system
will result in platform resets; subsequent patches will support these shutdown modes
properly.
Documentation/intel_txt.txt | 210 +++++++++++++++++++++
Documentation/x86/zero-page.txt | 1
arch/x86/include/asm/bootparam.h | 3
arch/x86/include/asm/fixmap.h | 3
arch/x86/include/asm/tboot.h | 197 ++++++++++++++++++++
arch/x86/kernel/Makefile | 1
arch/x86/kernel/setup.c | 4
arch/x86/kernel/tboot.c | 379 +++++++++++++++++++++++++++++++++++++++
security/Kconfig | 30 +++
9 files changed, 827 insertions(+), 1 deletion(-)
Signed-off-by: Joseph Cihula <joseph.cihula@intel.com>
Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Gang Wei <gang.wei@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
- is_single_threaded(task) is not safe unless task == current,
we can't use task->signal or task->mm.
- it doesn't make sense unless task == current, the task can
fork right after the check.
Rename it to current_is_single_threaded() and kill the argument.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Convert avc_audit in security/selinux/avc.c to use lsm_audit.h,
for better maintainability and for less code duplication.
- changed selinux to use common_audit_data instead of
avc_audit_data
- eliminated code in avc.c and used code from lsm_audit.h instead.
I have tested to make sure that the avcs look the same before and
after this patch.
Signed-off-by: Thomas Liu <tliu@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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>
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>
This patch fixes an imbalance message as reported by J.R. Okajima.
The IMA file counters are incremented in ima_path_check. If the
actual open fails, such as ETXTBSY, decrement the counters to
prevent unnecessary imbalance messages.
Reported-by: J.R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Added a call to free the avc_node_cache when inside selinux_disable because
it should not waste resources allocated during avc_init if SELinux is disabled
and the cache will never be used.
Signed-off-by: Thomas Liu <tliu@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
The ->ptrace_may_access() methods are named confusingly - the real
ptrace_may_access() returns a bool, while these security checks have
a retval convention.
Rename it to ptrace_access_check, to reduce the confusion factor.
[ Impact: cleanup, no code changed ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: James Morris <jmorris@namei.org>
Annotate seqfile ops with __releases and __acquires to stop sparse
complaining about unbalanced locking.
Signed-off-by: James Morris <jmorris@namei.org>
Reviewed-by: Serge Hallyn <serue@us.ibm.com>
Restore the optimization to skip revalidation in selinux_file_permission
if nothing has changed since the dentry_open checks, accidentally removed by
389fb800. Also remove redundant test from selinux_revalidate_file_permission.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: Paul Moore <paul.moore@hp.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
We can update bprm->cred->security inside tomoyo_find_next_domain().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
We can mark tomoyo_delete_domain() as a "static" function
by moving it from domain.c to common.c .
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
While walking through the whitelist, if the DEV_ALL item is found, no more
check is needed.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The attached patch adds support to generate audit messages on two cases.
The first one is a case when a multi-thread process tries to switch its
performing security context using setcon(3), but new security context is
not bounded by the old one.
type=SELINUX_ERR msg=audit(1245311998.599:17): \
op=security_bounded_transition result=denied \
oldcontext=system_u:system_r:httpd_t:s0 \
newcontext=system_u:system_r:guest_webapp_t:s0
The other one is a case when security_compute_av() masked any permissions
due to the type boundary violation.
type=SELINUX_ERR msg=audit(1245312836.035:32): \
op=security_compute_av reason=bounds \
scontext=system_u:object_r:user_webapp_t:s0 \
tcontext=system_u:object_r:shadow_t:s0:c0 \
tclass=file perms=getattr,open
Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
It is a cleanup patch to cut down a line within 80 columns.
Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
--
security/selinux/ss/services.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
Signed-off-by: James Morris <jmorris@namei.org>
* 'rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: rcu_sched_grace_period(): kill the bogus flush_signals()
rculist: use list_entry_rcu in places where it's appropriate
rculist.h: introduce list_entry_rcu() and list_first_entry_rcu()
rcu: Update RCU tracing documentation for __rcu_pending
rcu: Add __rcu_pending tracing to hierarchical RCU
RCU: make treercu be default
This patch adds some descriptions of lists and structures.
This patch contains no code changes.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
TOMOYO 2.2.0 is not using total_len field of "struct tomoyo_path_info".
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
Mimi Zohar
Eric Paris
Justin P. Mattock
Kees Cook
Guido Trentalancia
Stephen Smalley
Al Viro
Tetsuo Handa
KaiGai Kohei
James Morris
Jiri Slaby
Geert Uytterhoeven
David Howells
H Hartley Sweeten
Roel Kluin
Mimi Zohar
Linus Torvalds
Amerigo Wang
Julia Lawall
Jiri Kosina
David S. Miller
André Goddard Rosa
James Morris
Serge E. Hallyn
Eric Dumazet
Eric W. Biederman
John Johansen
Stephen Hemminger
Alexey Dobriyan
Oleg Nesterov
Ben Blum
Paul Moore
Nick Black
Marc Dionne
David P. Quigley
Ingo Molnar
Shane Wang
Andreas Schwab
Dave Jones
Thomas Liu
Arnaldo Carvalho de Melo
Joseph Cihula
Li Zefan