commit 66fc1303 ("mm: shmem_zero_setup
skip security check and lockdep conflict with XFS") caused a regression
for SELinux by disabling any SELinux checking of mprotect PROT_EXEC on
shared anonymous mappings.  However, even before that regression, the
checking on such mprotect PROT_EXEC calls was inconsistent with the
checking on a mmap PROT_EXEC call for a shared anonymous mapping.  On a
mmap, the security hook is passed a NULL file and knows it is dealing
with an anonymous mapping and therefore applies an execmem check and no
file checks.  On a mprotect, the security hook is passed a vma with a
non-NULL vm_file (as this was set from the internally-created shmem
file during mmap) and therefore applies the file-based execute check
and no execmem check.  Since the aforementioned commit now marks the
shmem zero inode with the S_PRIVATE flag, the file checks are disabled
and we have no checking at all on mprotect PROT_EXEC.  Add a test to
the mprotect hook logic for such private inodes, and apply an execmem
check in that case.  This makes the mmap and mprotect checking
consistent for shared anonymous mappings, as well as for /dev/zero and
ashmem.

Cc: <stable@vger.kernel.org> # 4.1.x
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Before calling into the filesystem, vfs_setxattr calls
security_inode_setxattr, which ends up calling selinux_inode_setxattr in
our case.  That returns -EOPNOTSUPP whenever SBLABEL_MNT is not set.
SBLABEL_MNT was supposed to be set by sb_finish_set_opts, which sets it
only if selinux_is_sblabel_mnt returns true.

The selinux_is_sblabel_mnt logic was broken by eadcabc6 "SELinux: do
all flags twiddling in one place", which didn't take into the account
the SECURITY_FS_USE_NATIVE behavior that had been introduced for nfs
with eb9ae686 "SELinux: Add new labeling type native labels".

This caused setxattr's of security labels over NFSv4.2 to fail.

Cc: stable@kernel.org # 3.13
Cc: Eric Paris <eparis@redhat.com>
Cc: David Quigley <dpquigl@davequigley.com>
Reported-by: NRichard Chan <rc556677@outlook.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
[PM: added the stable dependency]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Support per-file labeling of sysfs and pstore files based on
genfscon policy entries.  This is safe because the sysfs
and pstore directory tree cannot be manipulated by userspace,
except to unlink pstore entries.
This provides an alternative method of assigning per-file labeling
to sysfs or pstore files without needing to set the labels from
userspace on each boot.  The advantages of this approach are that
the labels are assigned as soon as the dentry is first instantiated
and userspace does not need to walk the sysfs or pstore tree and
set the labels on each boot.  The limitations of this approach are
that the labels can only be assigned based on pathname prefix matching.
You can initially assign labels using this mechanism and then change
them at runtime via setxattr if allowed to do so by policy.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Suggested-by: NDominick Grift <dac.override@gmail.com>
Acked-by: NJeff Vander Stoep <jeffv@google.com>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Add support for per-file labeling of debugfs files so that
we can distinguish them in policy.  This is particularly
important in Android where certain debugfs files have to be writable
by apps and therefore the debugfs directory tree can be read and
searched by all.

Since debugfs is entirely kernel-generated, the directory tree is
immutable by userspace, and the inodes are pinned in memory, we can
simply use the same approach as with proc and label the inodes from
policy based on pathname from the root of the debugfs filesystem.
Generalize the existing labeling support used for proc and reuse it
for debugfs too.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Update the set of SELinux netlink socket class definitions to match
the set of netlink protocols implemented by the kernel.  The
ip_queue implementation for the NETLINK_FIREWALL and NETLINK_IP6_FW protocols
was removed in d16cf20e, so we can remove
the corresponding class definitions as this is dead code.  Add new
classes for NETLINK_ISCSI, NETLINK_FIB_LOOKUP, NETLINK_CONNECTOR,
NETLINK_NETFILTER, NETLINK_GENERIC, NETLINK_SCSITRANSPORT, NETLINK_RDMA,
and NETLINK_CRYPTO so that we can distinguish among sockets created
for each of these protocols.  This change does not define the finer-grained
nlsmsg_read/write permissions or map specific nlmsg_type values to those
permissions in the SELinux nlmsgtab; if finer-grained control of these
sockets is desired/required, that can be added as a follow-on change.
We do not define a SELinux class for NETLINK_ECRYPTFS as the implementation
was removed in 624ae528.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

selinux_bprm_committed_creds()->__flush_signals() is not right, we
shouldn't clear TIF_SIGPENDING unconditionally. There can be other
reasons for signal_pending(): freezing(), JOBCTL_PENDING_MASK, and
potentially more.

Also change this code to check fatal_signal_pending() rather than
SIGNAL_GROUP_EXIT, it looks a bit better.

Now we can kill __flush_signals() before it finds another buggy user.

Note: this code looks racy, we can flush a signal which was sent after
the task SID has been updated.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

This prints the 'sclass' field as string instead of index in unrecognized netlink message.
The textual representation makes it easier to distinguish the right class.
Signed-off-by: NMarek Milkovic <mmilkovi@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
[PM: 80-char width fixes]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Instead of using a vector of security operations
with explicit, special case stacking of the capability
and yama hooks use lists of hooks with capability and
yama hooks included as appropriate.

The security_operations structure is no longer required.
Instead, there is a union of the function pointers that
allows all the hooks lists to use a common mechanism for
list management while retaining typing. Each module
supplies an array describing the hooks it provides instead
of a sparsely populated security_operations structure.
The description includes the element that gets put on
the hook list, avoiding the issues surrounding individual
element allocation.

The method for registering security modules is changed to
reflect the information available. The method for removing
a module, currently only used by SELinux, has also changed.
It should be generic now, however if there are potential
race conditions based on ordering of hook removal that needs
to be addressed by the calling module.

The security hooks are called from the lists and the first
failure is returned.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Acked-by: NJohn Johansen <john.johansen@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NPaul Moore <paul@paul-moore.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

Add a list header for each security hook. They aren't used until
later in the patch series. They are grouped together in a structure
so that there doesn't need to be an external address for each.

Macro-ize the initialization of the security_operations
for each security module in anticipation of changing out
the security_operations structure.
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Acked-by: NJohn Johansen <john.johansen@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NPaul Moore <paul@paul-moore.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

The security.h header file serves two purposes,
interfaces for users of the security modules and
interfaces for security modules. Users of the
security modules don't need to know about what's
in the security_operations structure, so pull it
out into it's own header, lsm_hooks.h
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Acked-by: NJohn Johansen <john.johansen@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Acked-by: NPaul Moore <paul@paul-moore.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

inode_follow_link now takes an inode and rcu flag as well as the
dentry.

inode is used in preference to d_backing_inode(dentry), particularly
in RCU-walk mode.

selinux_inode_follow_link() gets dentry_has_perm() and
inode_has_perm() open-coded into it so that it can call
avc_has_perm_flags() in way that is safe if LOOKUP_RCU is set.

Calling avc_has_perm_flags() with rcu_read_lock() held means
that when avc_has_perm_noaudit calls avc_compute_av(), the attempt
to rcu_read_unlock() before calling security_compute_av() will not
actually drop the RCU read-lock.

However as security_compute_av() is completely in a read_lock()ed
region, it should be safe with the RCU read-lock held.
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This allows MAY_NOT_BLOCK to be passed, in RCU-walk mode, through
the new avc_has_perm_flags() to avc_audit() and thence the slow_avc_audit.
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

No ->inode_follow_link() methods use the nameidata arg, and
it is about to become private to namei.c.
So remove from all inode_follow_link() functions.
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

most of the ->d_inode uses there refer to the same inode IO would
go to, i.e. d_backing_inode()
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Pass the nf_hook_state all the way down into the hook
functions themselves.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit ca10b9e9.

No longer needed after commit eb8895de
("tcp: tcp_make_synack() should use sock_wmalloc")

When under SYNFLOOD, we build lot of SYNACK and hit false sharing
because of multiple modifications done on sk_listener->sk_wmem_alloc

Since tcp_make_synack() uses sock_wmalloc(), there is no need
to call skb_set_owner_w() again, as this adds two atomic operations.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Convert the following where appropriate:

 (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry).

 (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry).

 (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry).  This is actually more
     complicated than it appears as some calls should be converted to
     d_can_lookup() instead.  The difference is whether the directory in
     question is a real dir with a ->lookup op or whether it's a fake dir with
     a ->d_automount op.

In some circumstances, we can subsume checks for dentry->d_inode not being
NULL into this, provided we the code isn't in a filesystem that expects
d_inode to be NULL if the dirent really *is* negative (ie. if we're going to
use d_inode() rather than d_backing_inode() to get the inode pointer).

Note that the dentry type field may be set to something other than
DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS
manages the fall-through from a negative dentry to a lower layer.  In such a
case, the dentry type of the negative union dentry is set to the same as the
type of the lower dentry.

However, if you know d_inode is not NULL at the call site, then you can use
the d_is_xxx() functions even in a filesystem.

There is one further complication: a 0,0 chardev dentry may be labelled
DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE.  Strictly, this was
intended for special directory entry types that don't have attached inodes.

The following perl+coccinelle script was used:

use strict;

my @callers;
open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') ||
    die "Can't grep for S_ISDIR and co. callers";
@callers = <$fd>;
close($fd);
unless (@callers) {
    print "No matches\n";
    exit(0);
}

my @cocci = (
    '@@',
    'expression E;',
    '@@',
    '',
    '- S_ISLNK(E->d_inode->i_mode)',
    '+ d_is_symlink(E)',
    '',
    '@@',
    'expression E;',
    '@@',
    '',
    '- S_ISDIR(E->d_inode->i_mode)',
    '+ d_is_dir(E)',
    '',
    '@@',
    'expression E;',
    '@@',
    '',
    '- S_ISREG(E->d_inode->i_mode)',
    '+ d_is_reg(E)' );

my $coccifile = "tmp.sp.cocci";
open($fd, ">$coccifile") || die $coccifile;
print($fd "$_\n") || die $coccifile foreach (@cocci);
close($fd);

foreach my $file (@callers) {
    chomp $file;
    print "Processing ", $file, "\n";
    system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 ||
	die "spatch failed";
}

[AV: overlayfs parts skipped]
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Use d_is_positive() rather than testing dentry->d_inode in SELinux to get rid
of direct references to d_inode outside of the VFS.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

- add "pstore" and "debugfs" to list of in-core exceptions
- change fstype checks to boolean equation
- change from strncmp to strcmp for checking
Signed-off-by: NMark Salyzyn <salyzyn@android.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
[PM: tweaked the subject line prefix to "selinux"]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

While the filesystem labeling method is only printed at the KERN_DEBUG
level, this still appears in dmesg and on modern Linux distributions
that create a lot of tmpfs mounts for session handling, the dmesg can
easily be filled with a lot of "SELinux: initialized (dev X ..."
messages.  This patch removes this notification for the normal case
but leaves the error message intact (displayed when mounting a
filesystem with an unknown labeling behavior).
Reported-by: NDave Jones <davej@codemonkey.org.uk>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Add security hooks to the binder and implement the hooks for SELinux.
The security hooks enable security modules such as SELinux to implement
controls over binder IPC.  The security hooks include support for
controlling what process can become the binder context manager
(binder_set_context_mgr), controlling the ability of a process
to invoke a binder transaction/IPC to another process (binder_transaction),
controlling the ability of a process to transfer a binder reference to
another process (binder_transfer_binder), and controlling the ability
of a process to transfer an open file to another process (binder_transfer_file).

These hooks have been included in the Android kernel trees since Android 4.3.

(Updated to reflect upstream relocation and changes to the binder driver,
changes to the LSM audit data structures, coding style cleanups, and
to add inline documentation for the hooks).
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NNick Kralevich <nnk@google.com>
Acked-by: NJeffrey Vander Stoep <jeffv@google.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

security_ops is not used in this file.
Signed-off-by: NYao Dongdong <yaodongdong@huawei.com>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Convert WARN_ONCE() to printk() in selinux_nlmsg_perm().

After conversion from audit_log() in commit e173fb26, WARN_ONCE() was
deemed too alarmist, so switch it to printk().
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
[PM: Changed to printk(WARNING) so we catch all of the different
 invalid netlink messages.  In Richard's defense, he brought this
 point up earlier, but I didn't understand his point at the time.]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

sb_finish_set_opts() can race with inode_free_security()
when initializing inode security structures for inodes
created prior to initial policy load or by the filesystem
during ->mount().   This appears to have always been
a possible race, but commit 3dc91d43 ("SELinux:  Fix possible
NULL pointer dereference in selinux_inode_permission()")
made it more evident by immediately reusing the unioned
list/rcu element  of the inode security structure for call_rcu()
upon an inode_free_security().  But the underlying issue
was already present before that commit as a possible use-after-free
of isec.

Shivnandan Kumar reported the list corruption and proposed
a patch to split the list and rcu elements out of the union
as separate fields of the inode_security_struct so that setting
the rcu element would not affect the list element.  However,
this would merely hide the issue and not truly fix the code.

This patch instead moves up the deletion of the list entry
prior to dropping the sbsec->isec_lock initially.  Then,
if the inode is dropped subsequently, there will be no further
references to the isec.
Reported-by: NShivnandan Kumar <shivnandan.k@samsung.com>
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Cc: stable@vger.kernel.org
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Convert audit_log() call to WARN_ONCE().

Rename "type=" to nlmsg_type=" to avoid confusion with the audit record
type.

Added "protocol=" to help track down which protocol (NETLINK_AUDIT?) was used
within the netlink protocol family.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
[Rewrote the patch subject line]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

While SELinux largely ignores namespaces, for good reason, there are
some places where it needs to at least be aware of namespaces in order
to function correctly.  Network namespaces are one example.  Basic
awareness of network namespaces are necessary in order to match a
network interface's index number to an actual network device.

This patch corrects a problem with network interfaces added to a
non-init namespace, and can be reproduced with the following commands:

 [NOTE: the NetLabel configuration is here only to active the dynamic
        networking controls ]

 # netlabelctl unlbl add default address:0.0.0.0/0 \
   label:system_u:object_r:unlabeled_t:s0
 # netlabelctl unlbl add default address:::/0 \
   label:system_u:object_r:unlabeled_t:s0
 # netlabelctl cipsov4 add pass doi:100 tags:1
 # netlabelctl map add domain:lspp_test_netlabel_t \
   protocol:cipsov4,100

 # ip link add type veth
 # ip netns add myns
 # ip link set veth1 netns myns
 # ip a add dev veth0 10.250.13.100/24
 # ip netns exec myns ip a add dev veth1 10.250.13.101/24
 # ip l set veth0 up
 # ip netns exec myns ip l set veth1 up

 # ping -c 1 10.250.13.101
 # ip netns exec myns ping -c 1 10.250.13.100
Reported-by: NJiri Jaburek <jjaburek@redhat.com>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

security_file_set_fowner always returns 0, so make it f_setown and
__f_setown void return functions and fix up the error handling in the
callers.

Cc: linux-security-module@vger.kernel.org
Signed-off-by: NJeff Layton <jlayton@primarydata.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

Push ipv4 and ipv6 nf hooks into single array and register/unregister
them via single call.
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

A previous commit c0828e50 ("selinux:
process labeled IPsec TCP SYN-ACK packets properly in
selinux_ip_postroute()") mistakenly left out a 'break' from a switch
statement which caused problems with IPv6 traffic.

Thanks to Florian Westphal for reporting and debugging the issue.
Reported-by: NFlorian Westphal <fwestpha@redhat.com>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

If the callee SID is bounded by the caller SID, then allowing
the transition to occur poses no risk of privilege escalation and we can
therefore safely allow the transition to occur.  Add this exemption
for both the case where a transition was explicitly requested by the
application and the case where an automatic transition is defined in
policy.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

This reverts commit 4da6daf4.

Unfortunately, the commit in question caused problems with Bluetooth
devices, specifically it caused them to get caught in the newly
created BUG_ON() check.  The AF_ALG problem still exists, but will be
addressed in a future patch.

Cc: stable@vger.kernel.org
Signed-off-by: NPaul Moore <pmoore@redhat.com>

The sock_graft() hook has special handling for AF_INET, AF_INET, and
AF_UNIX sockets as those address families have special hooks which
label the sock before it is attached its associated socket.
Unfortunately, the sock_graft() hook was missing a default approach
to labeling sockets which meant that any other address family which
made use of connections or the accept() syscall would find the
returned socket to be in an "unlabeled" state.  This was recently
demonstrated by the kcrypto/AF_ALG subsystem and the newly released
cryptsetup package (cryptsetup v1.6.5 and later).

This patch preserves the special handling in selinux_sock_graft(),
but adds a default behavior - setting the sock's label equal to the
associated socket - which resolves the problem with AF_ALG and
presumably any other address family which makes use of accept().

Cc: stable@vger.kernel.org
Signed-off-by: NPaul Moore <pmoore@redhat.com>
Tested-by: NMilan Broz <gmazyland@gmail.com>

When flushing the AVC, such as during a policy load, the various
network caches are also flushed, with each making a call to
synchronize_net() which has shown to be expensive in some cases.
This patch consolidates the network cache flushes into a single AVC
callback which only calls synchronize_net() once for each AVC cache
flush.
Reported-by: NJaejyn Shin <flagon22bass@gmail.com>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

We presently prevent processes from using setexecon() to set the
security label of exec()'d processes when NO_NEW_PRIVS is enabled by
returning an error; however, we silently ignore setexeccon() when
exec()'ing from a nosuid mounted filesystem.  This patch makes things
a bit more consistent by returning an error in the setexeccon()/nosuid
case.
Signed-off-by: NPaul Moore <pmoore@redhat.com>
Acked-by: NAndy Lutomirski <luto@amacapital.net>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>

We cannot presently tell from an avc: denied message whether access was in
fact denied or was allowed due to global or per-domain permissive mode.
Add a permissive= field to the avc message to reflect this information.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

We presently prevent processes from using setexecon() to set the
security label of exec()'d processes when NO_NEW_PRIVS is enabled by
returning an error; however, we silently ignore setexeccon() when
exec()'ing from a nosuid mounted filesystem.  This patch makes things
a bit more consistent by returning an error in the setexeccon()/nosuid
case.
Signed-off-by: NPaul Moore <pmoore@redhat.com>
Acked-by: NAndy Lutomirski <luto@amacapital.net>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>

We cannot presently tell from an avc: denied message whether access was in
fact denied or was allowed due to global or per-domain permissive mode.
Add a permissive= field to the avc message to reflect this information.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

File-private locks have been merged into Linux for v3.15, and *now*
people are commenting that the name and macro definitions for the new
file-private locks suck.

...and I can't even disagree. The names and command macros do suck.

We're going to have to live with these for a long time, so it's
important that we be happy with the names before we're stuck with them.
The consensus on the lists so far is that they should be rechristened as
"open file description locks".

The name isn't a big deal for the kernel, but the command macros are not
visually distinct enough from the traditional POSIX lock macros. The
glibc and documentation folks are recommending that we change them to
look like F_OFD_{GETLK|SETLK|SETLKW}. That lessens the chance that a
programmer will typo one of the commands wrong, and also makes it easier
to spot this difference when reading code.

This patch makes the following changes that I think are necessary before
v3.15 ships:

1) rename the command macros to their new names. These end up in the uapi
   headers and so are part of the external-facing API. It turns out that
   glibc doesn't actually use the fcntl.h uapi header, but it's hard to
   be sure that something else won't. Changing it now is safest.

2) make the the /proc/locks output display these as type "OFDLCK"

Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Carlos O'Donell <carlos@redhat.com>
Cc: Stefan Metzmacher <metze@samba.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Frank Filz <ffilzlnx@mindspring.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: NJeff Layton <jlayton@redhat.com>

Due to some unfortunate history, POSIX locks have very strange and
unhelpful semantics. The thing that usually catches people by surprise
is that they are dropped whenever the process closes any file descriptor
associated with the inode.

This is extremely problematic for people developing file servers that
need to implement byte-range locks. Developers often need a "lock
management" facility to ensure that file descriptors are not closed
until all of the locks associated with the inode are finished.

Additionally, "classic" POSIX locks are owned by the process. Locks
taken between threads within the same process won't conflict with one
another, which renders them useless for synchronization between threads.

This patchset adds a new type of lock that attempts to address these
issues. These locks conflict with classic POSIX read/write locks, but
have semantics that are more like BSD locks with respect to inheritance
and behavior on close.

This is implemented primarily by changing how fl_owner field is set for
these locks. Instead of having them owned by the files_struct of the
process, they are instead owned by the filp on which they were acquired.
Thus, they are inherited across fork() and are only released when the
last reference to a filp is put.

These new semantics prevent them from being merged with classic POSIX
locks, even if they are acquired by the same process. These locks will
also conflict with classic POSIX locks even if they are acquired by
the same process or on the same file descriptor.

The new locks are managed using a new set of cmd values to the fcntl()
syscall. The initial implementation of this converts these values to
"classic" cmd values at a fairly high level, and the details are not
exposed to the underlying filesystem. We may eventually want to push
this handing out to the lower filesystem code but for now I don't
see any need for it.

Also, note that with this implementation the new cmd values are only
available via fcntl64() on 32-bit arches. There's little need to
add support for legacy apps on a new interface like this.
Signed-off-by: NJeff Layton <jlayton@redhat.com>