Add a policy revision file to find the current revision of a ns's policy.
There is a revision file per ns, as well as a virtualized global revision
file in the base apparmor fs directory. The global revision file when
opened will provide the revision of the opening task namespace.
The revision file can be waited on via select/poll to detect apparmor
policy changes from the last read revision of the opened file. This
means that the revision file must be read after the select/poll other
wise update data will remain ready for reading.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Virtualize the apparmor policy/ directory so that the current
namespace affects what part of policy is seen. To do this convert to
using apparmorfs for policy namespace files and setup a magic symlink
in the securityfs apparmor dir to access those files.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Seth Arnold <seth.arnold@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
prefixes are used for fns/data that are not static to apparmorfs.c
with the prefixes being
aafs - special magic apparmorfs for policy namespace data
aa_sfs - for fns/data that go into securityfs
aa_fs - for fns/data that may be used in the either of aafs or
securityfs
Signed-off-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Seth Arnold <seth.arnold@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
AppArmor policy needs to be able to be resolved based on the policy
namespace a task is confined by. Add a base apparmorfs filesystem that
(like nsfs) will exist as a kern mount and be accessed via jump_link
through a securityfs file.
Setup the base apparmorfs fns and data, but don't use it yet.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Seth Arnold <seth.arnold@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
The loaddata sets cover more than just a single profile and should
be tracked at the ns level. Move the load data files under the namespace
and reference the files from the profiles via a symlink.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Seth Arnold <seth.arnold@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
We can either return PTR_ERR(NULL) or a PTR_ERR(a valid pointer) here.
Returning NULL is probably not good, but since this happens at boot
then we are probably already toasted if we were to hit this bug in real
life. In other words, it seems like a very low severity bug to me.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Two single characters (line breaks) should be put into a sequence.
Thus use the corresponding function "seq_putc".
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: John Johansen <john.johansen@canonical.com>
A bit of data was put into a sequence by two separate function calls.
Print the same data by a single function call instead.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: John Johansen <john.johansen@canonical.com>
CURRENT_TIME macro is not y2038 safe on 32 bit systems.
The patch replaces all the uses of CURRENT_TIME by current_time().
This is also in preparation for the patch that transitions vfs
timestamps to use 64 bit time and hence make them y2038 safe.
current_time() is also planned to be transitioned to y2038 safe behavior
along with this change.
CURRENT_TIME macro will be deleted before merging the aforementioned
change.
Link: http://lkml.kernel.org/r/1491613030-11599-11-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "kvmalloc", v5.
There are many open coded kmalloc with vmalloc fallback instances in the
tree. Most of them are not careful enough or simply do not care about
the underlying semantic of the kmalloc/page allocator which means that
a) some vmalloc fallbacks are basically unreachable because the kmalloc
part will keep retrying until it succeeds b) the page allocator can
invoke a really disruptive steps like the OOM killer to move forward
which doesn't sound appropriate when we consider that the vmalloc
fallback is available.
As it can be seen implementing kvmalloc requires quite an intimate
knowledge if the page allocator and the memory reclaim internals which
strongly suggests that a helper should be implemented in the memory
subsystem proper.
Most callers, I could find, have been converted to use the helper
instead. This is patch 6. There are some more relying on __GFP_REPEAT
in the networking stack which I have converted as well and Eric Dumazet
was not opposed [2] to convert them as well.
[1] http://lkml.kernel.org/r/20170130094940.13546-1-mhocko@kernel.org
[2] http://lkml.kernel.org/r/1485273626.16328.301.camel@edumazet-glaptop3.roam.corp.google.com
This patch (of 9):
Using kmalloc with the vmalloc fallback for larger allocations is a
common pattern in the kernel code. Yet we do not have any common helper
for that and so users have invented their own helpers. Some of them are
really creative when doing so. Let's just add kv[mz]alloc and make sure
it is implemented properly. This implementation makes sure to not make
a large memory pressure for > PAGE_SZE requests (__GFP_NORETRY) and also
to not warn about allocation failures. This also rules out the OOM
killer as the vmalloc is a more approapriate fallback than a disruptive
user visible action.
This patch also changes some existing users and removes helpers which
are specific for them. In some cases this is not possible (e.g.
ext4_kvmalloc, libcfs_kvzalloc) because those seems to be broken and
require GFP_NO{FS,IO} context which is not vmalloc compatible in general
(note that the page table allocation is GFP_KERNEL). Those need to be
fixed separately.
While we are at it, document that __vmalloc{_node} about unsupported gfp
mask because there seems to be a lot of confusion out there.
kvmalloc_node will warn about GFP_KERNEL incompatible (which are not
superset) flags to catch new abusers. Existing ones would have to die
slowly.
[sfr@canb.auug.org.au: f2fs fixup]
Link: http://lkml.kernel.org/r/20170320163735.332e64b7@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170306103032.2540-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Andreas Dilger <adilger@dilger.ca> [ext4 part]
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow a profile to carry extra data that can be queried via userspace.
This provides a means to store extra data in a profile that a trusted
helper can extract and use from live policy.
Signed-off-by: William Hua <william.hua@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Moving the use of fqname to later allows learning profiles to be based
on the fqname request instead of just the hname. It also allows cleaning
up some of the name parsing and lookup by allowing the use of
the fqlookupn_profile() lib fn.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Having ops be an integer that is an index into an op name table is
awkward and brittle. Every op change requires an edit for both the
op constant and a string in the table. Instead switch to using const
strings directly, eliminating the need for the table that needs to
be kept in sync.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Store loaded policy and allow introspecting it through apparmorfs. This
has several uses from debugging, policy validation, and policy checkpoint
and restore for containers.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Policy management will be expanded beyond traditional unconfined root.
This will require knowning the profile of the task doing the management
and the ns view.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Borrow the special null device file from selinux to "close" fds that
don't have sufficient permissions at exec time.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Commit 9f834ec18d ("binfmt_elf: switch to new creds when switching to new mm")
changed when the creds are installed by the binfmt_elf handler. This
affects which creds are used to mmap the executable into the address
space. Which can have an affect on apparmor policy.
Add a flag to apparmor at
/sys/kernel/security/apparmor/features/domain/fix_binfmt_elf_mmap
to make it possible to detect this semantic change so that the userspace
tools and the regression test suite can correctly deal with the change.
BugLink: http://bugs.launchpad.net/bugs/1630069
Signed-off-by: John Johansen <john.johansen@canonical.com>
Newer policy encodes more than just version in the version tag,
so add masking to make sure the comparison remains correct.
Note: this is fully compatible with older policy as it will never set
the bits being masked out.
Signed-off-by: John Johansen <john.johansen@canonical.com>
prepare_ns() will need to be called from alternate views, and namespaces
will need to be created via different interfaces. So refactor and
allow specifying the view ns.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Policy namespaces will be diverging from profile management and
expanding so put it in its own file.
Signed-off-by: John Johansen <john.johansen@canonical.com>
CURRENT_TIME macro is not appropriate for filesystems as it
doesn't use the right granularity for filesystem timestamps.
Use current_time() instead.
CURRENT_TIME is also not y2038 safe.
This is also in preparation for the patch that transitions
vfs timestamps to use 64 bit time and hence make them
y2038 safe. As part of the effort current_time() will be
extended to do range checks. Hence, it is necessary for all
file system timestamps to use current_time(). Also,
current_time() will be transitioned along with vfs to be
y2038 safe.
Note that whenever a single call to current_time() is used
to change timestamps in different inodes, it is because they
share the same time granularity.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Felipe Balbi <balbi@kernel.org>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
list_next_entry has been defined in list.h, so I replace list_entry_next
with it.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
... except where that code acts as a filesystem driver, rather than
working with dentries given to it.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
BugLink: http://bugs.launchpad.net/bugs/1235977
The profile introspection seq file has a locking bug when policy is viewed
from a virtual root (task in a policy namespace), introspection from the
real root is not affected.
The test for root
while (parent) {
is correct for the real root, but incorrect for tasks in a policy namespace.
This allows the task to walk backup the policy tree past its virtual root
causing it to be unlocked before the virtual root should be in the p_stop
fn.
This results in the following lockdep back trace:
[ 78.479744] [ BUG: bad unlock balance detected! ]
[ 78.479792] 3.11.0-11-generic #17 Not tainted
[ 78.479838] -------------------------------------
[ 78.479885] grep/2223 is trying to release lock (&ns->lock) at:
[ 78.479952] [<ffffffff817bf3be>] mutex_unlock+0xe/0x10
[ 78.480002] but there are no more locks to release!
[ 78.480037]
[ 78.480037] other info that might help us debug this:
[ 78.480037] 1 lock held by grep/2223:
[ 78.480037] #0: (&p->lock){+.+.+.}, at: [<ffffffff812111bd>] seq_read+0x3d/0x3d0
[ 78.480037]
[ 78.480037] stack backtrace:
[ 78.480037] CPU: 0 PID: 2223 Comm: grep Not tainted 3.11.0-11-generic #17
[ 78.480037] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 78.480037] ffffffff817bf3be ffff880007763d60 ffffffff817b97ef ffff8800189d2190
[ 78.480037] ffff880007763d88 ffffffff810e1c6e ffff88001f044730 ffff8800189d2190
[ 78.480037] ffffffff817bf3be ffff880007763e00 ffffffff810e5bd6 0000000724fe56b7
[ 78.480037] Call Trace:
[ 78.480037] [<ffffffff817bf3be>] ? mutex_unlock+0xe/0x10
[ 78.480037] [<ffffffff817b97ef>] dump_stack+0x54/0x74
[ 78.480037] [<ffffffff810e1c6e>] print_unlock_imbalance_bug+0xee/0x100
[ 78.480037] [<ffffffff817bf3be>] ? mutex_unlock+0xe/0x10
[ 78.480037] [<ffffffff810e5bd6>] lock_release_non_nested+0x226/0x300
[ 78.480037] [<ffffffff817bf2fe>] ? __mutex_unlock_slowpath+0xce/0x180
[ 78.480037] [<ffffffff817bf3be>] ? mutex_unlock+0xe/0x10
[ 78.480037] [<ffffffff810e5d5c>] lock_release+0xac/0x310
[ 78.480037] [<ffffffff817bf2b3>] __mutex_unlock_slowpath+0x83/0x180
[ 78.480037] [<ffffffff817bf3be>] mutex_unlock+0xe/0x10
[ 78.480037] [<ffffffff81376c91>] p_stop+0x51/0x90
[ 78.480037] [<ffffffff81211408>] seq_read+0x288/0x3d0
[ 78.480037] [<ffffffff811e9d9e>] vfs_read+0x9e/0x170
[ 78.480037] [<ffffffff811ea8cc>] SyS_read+0x4c/0xa0
[ 78.480037] [<ffffffff817ccc9d>] system_call_fastpath+0x1a/0x1f
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Provide userspace the ability to introspect a sha1 hash value for each
profile currently loaded.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
Add the dynamic namespace relative profiles file to the interace, to allow
introspection of loaded profiles and their modes.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Add the ability to take in and report a human readable profile attachment
string for profiles so that attachment specifications can be easily
inspected.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
Add basic interface files to access namespace and profile information.
The interface files are created when a profile is loaded and removed
when the profile or namespace is removed.
Signed-off-by: John Johansen <john.johansen@canonical.com>
previously profiles had to be loaded one at a time, which could result
in cases where a replacement of a set would partially succeed, and then fail
resulting in inconsistent policy.
Allow multiple profiles to replaced "atomically" so that the replacement
either succeeds or fails for the entire set of profiles.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Add a policy directory to features to contain features that can affect
policy compilation but do not affect mediation. Eg of such features would
be types of dfa compression supported, etc.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Since the parser needs to know which rlimits are known to the kernel,
export the list via a mask file in the "rlimit" subdirectory in the
securityfs "features" directory.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Create the "file" directory in the securityfs for tracking features
related to files.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
This adds the "features" subdirectory to the AppArmor securityfs
to display boolean features flags and the known capability mask.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Use a file tree structure to represent the AppArmor securityfs.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
* 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
vfs: make no_llseek the default
vfs: don't use BKL in default_llseek
llseek: automatically add .llseek fop
libfs: use generic_file_llseek for simple_attr
mac80211: disallow seeks in minstrel debug code
lirc: make chardev nonseekable
viotape: use noop_llseek
raw: use explicit llseek file operations
ibmasmfs: use generic_file_llseek
spufs: use llseek in all file operations
arm/omap: use generic_file_llseek in iommu_debug
lkdtm: use generic_file_llseek in debugfs
net/wireless: use generic_file_llseek in debugfs
drm: use noop_llseek
Actually I think in this case the appropriate thing to do is to BUG as there
is currently a case (remove) where the alloc_size needs to be larger than
the copy_size, and if copy_size is ever greater than alloc_size there is
a mistake in the caller code.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.
The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.
New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time. Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.
The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.
Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.
Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.
===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
// but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}
@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}
@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}
@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}
@ fops0 @
identifier fops;
@@
struct file_operations fops = {
...
};
@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
.llseek = llseek_f,
...
};
@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
.read = read_f,
...
};
@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
.write = write_f,
...
};
@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
.open = open_f,
...
};
// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
... .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};
@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
... .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};
// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
... .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};
// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};
// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};
@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+ .llseek = default_llseek, /* write accesses f_pos */
};
// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////
@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
.write = write_f,
.read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};
@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};
@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};
@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
The /proc/<pid>/attr/* interface is used for process introspection and
commands. While the apparmorfs interface is used for global introspection
and loading and removing policy.
The interface currently only contains the files necessary for loading
policy, and will be extended in the future to include sysfs style
single per file introspection inteface.
The old AppArmor 2.4 interface files have been removed into a compatibility
patch, that distros can use to maintain backwards compatibility.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
John Johansen