may_create() rejects creation of inodes with ids which lack a
mapping into s_user_ns. However for O_CREAT may_o_create() is
is used instead. Add a similar check there.

Fixes: 036d5236 ("vfs: Don't create inodes with a uid or gid unknown to the vfs")
Signed-off-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Instead of making the files owned by the GLOBAL_ROOT_USER.  Make
non-dumpable files whose mm has always lived in a user namespace owned
by the user namespace root.  This allows the container root to have
things work as expected in a container.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

With previous changes every location that tests for
LSM_UNSAFE_PTRACE_CAP also tests for LSM_UNSAFE_PTRACE making the
LSM_UNSAFE_PTRACE_CAP redundant, so remove it.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

This patchset converts inotify to using the newly introduced
per-userns sysctl infrastructure.

Currently the inotify instances/watches are being accounted in the
user_struct structure. This means that in setups where multiple
users in unprivileged containers map to the same underlying
real user (i.e. pointing to the same user_struct) the inotify limits
are going to be shared as well, allowing one user(or application) to exhaust
all others limits.

Fix this by switching the inotify sysctls to using the
per-namespace/per-user limits. This will allow the server admin to
set sensible global limits, which can further be tuned inside every
individual user namespace. Additionally, in order to preserve the
sysctl ABI make the existing inotify instances/watches sysctls
modify the values of the initial user namespace.
Signed-off-by: NNikolay Borisov <n.borisov.lkml@gmail.com>
Acked-by: NJan Kara <jack@suse.cz>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Fixes CVE-2016-9191, proc_sys_readdir doesn't drop reference
added by grab_header when return from !dir_emit_dots path.
It can cause any path called unregister_sysctl_table will
wait forever.

The calltrace of CVE-2016-9191:

[ 5535.960522] Call Trace:
[ 5535.963265]  [<ffffffff817cdaaf>] schedule+0x3f/0xa0
[ 5535.968817]  [<ffffffff817d33fb>] schedule_timeout+0x3db/0x6f0
[ 5535.975346]  [<ffffffff817cf055>] ? wait_for_completion+0x45/0x130
[ 5535.982256]  [<ffffffff817cf0d3>] wait_for_completion+0xc3/0x130
[ 5535.988972]  [<ffffffff810d1fd0>] ? wake_up_q+0x80/0x80
[ 5535.994804]  [<ffffffff8130de64>] drop_sysctl_table+0xc4/0xe0
[ 5536.001227]  [<ffffffff8130de17>] drop_sysctl_table+0x77/0xe0
[ 5536.007648]  [<ffffffff8130decd>] unregister_sysctl_table+0x4d/0xa0
[ 5536.014654]  [<ffffffff8130deff>] unregister_sysctl_table+0x7f/0xa0
[ 5536.021657]  [<ffffffff810f57f5>] unregister_sched_domain_sysctl+0x15/0x40
[ 5536.029344]  [<ffffffff810d7704>] partition_sched_domains+0x44/0x450
[ 5536.036447]  [<ffffffff817d0761>] ? __mutex_unlock_slowpath+0x111/0x1f0
[ 5536.043844]  [<ffffffff81167684>] rebuild_sched_domains_locked+0x64/0xb0
[ 5536.051336]  [<ffffffff8116789d>] update_flag+0x11d/0x210
[ 5536.057373]  [<ffffffff817cf61f>] ? mutex_lock_nested+0x2df/0x450
[ 5536.064186]  [<ffffffff81167acb>] ? cpuset_css_offline+0x1b/0x60
[ 5536.070899]  [<ffffffff810fce3d>] ? trace_hardirqs_on+0xd/0x10
[ 5536.077420]  [<ffffffff817cf61f>] ? mutex_lock_nested+0x2df/0x450
[ 5536.084234]  [<ffffffff8115a9f5>] ? css_killed_work_fn+0x25/0x220
[ 5536.091049]  [<ffffffff81167ae5>] cpuset_css_offline+0x35/0x60
[ 5536.097571]  [<ffffffff8115aa2c>] css_killed_work_fn+0x5c/0x220
[ 5536.104207]  [<ffffffff810bc83f>] process_one_work+0x1df/0x710
[ 5536.110736]  [<ffffffff810bc7c0>] ? process_one_work+0x160/0x710
[ 5536.117461]  [<ffffffff810bce9b>] worker_thread+0x12b/0x4a0
[ 5536.123697]  [<ffffffff810bcd70>] ? process_one_work+0x710/0x710
[ 5536.130426]  [<ffffffff810c3f7e>] kthread+0xfe/0x120
[ 5536.135991]  [<ffffffff817d4baf>] ret_from_fork+0x1f/0x40
[ 5536.142041]  [<ffffffff810c3e80>] ? kthread_create_on_node+0x230/0x230

One cgroup maintainer mentioned that "cgroup is trying to offline
a cpuset css, which takes place under cgroup_mutex.  The offlining
ends up trying to drain active usages of a sysctl table which apprently
is not happening."
The real reason is that proc_sys_readdir doesn't drop reference added
by grab_header when return from !dir_emit_dots path. So this cpuset
offline path will wait here forever.

See here for details: http://www.openwall.com/lists/oss-security/2016/11/04/13

Fixes: f0c3b509 ("[readdir] convert procfs")
Cc: stable@vger.kernel.org
Reported-by: NCAI Qian <caiqian@redhat.com>
Tested-by: NYang Shukui <yangshukui@huawei.com>
Signed-off-by: NZhou Chengming <zhouchengming1@huawei.com>
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Add MS_KERNMOUNT to the flags that are passed.
Use sget_userns and force &init_user_ns instead of calling sget so that
even if called from a weird context the internal filesystem will be
considered to be in the intial user namespace.

Luis Ressel reported that the the failure to pass MS_KERNMOUNT into
mount_pseudo broke his in development graphics driver that uses the
generic drm infrastructure.  I am not certain the deriver was bug
free in it's usage of that infrastructure but since
mount_pseudo_xattr can never be triggered by userspace it is clearer
and less error prone, and less problematic for the code to be explicit.
Reported-by: NLuis Ressel <aranea@aixah.de>
Tested-by: NLuis Ressel <aranea@aixah.de>
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Protecting the mountpoint hashtable with namespace_sem was sufficient
until a call to umount_mnt was added to mntput_no_expire.  At which
point it became possible for multiple calls of put_mountpoint on
the same hash chain to happen on the same time.

Kristen Johansen <kjlx@templeofstupid.com> reported:
> This can cause a panic when simultaneous callers of put_mountpoint
> attempt to free the same mountpoint.  This occurs because some callers
> hold the mount_hash_lock, while others hold the namespace lock.  Some
> even hold both.
>
> In this submitter's case, the panic manifested itself as a GP fault in
> put_mountpoint() when it called hlist_del() and attempted to dereference
> a m_hash.pprev that had been poisioned by another thread.

Al Viro observed that the simple fix is to switch from using the namespace_sem
to the mount_lock to protect the mountpoint hash table.

I have taken Al's suggested patch moved put_mountpoint in pivot_root
(instead of taking mount_lock an additional time), and have replaced
new_mountpoint with get_mountpoint a function that does the hash table
lookup and addition under the mount_lock.   The introduction of get_mounptoint
ensures that only the mount_lock is needed to manipulate the mountpoint
hashtable.

d_set_mounted is modified to only set DCACHE_MOUNTED if it is not
already set.  This allows get_mountpoint to use the setting of
DCACHE_MOUNTED to ensure adding a struct mountpoint for a dentry
happens exactly once.

Cc: stable@vger.kernel.org
Fixes: ce07d891 ("mnt: Honor MNT_LOCKED when detaching mounts")
Reported-by: NKrister Johansen <kjlx@templeofstupid.com>
Suggested-by: NAl Viro <viro@ZenIV.linux.org.uk>
Acked-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Now that dax_iomap_fault() calls ->iomap_begin() without entry lock, we
can use transaction starting in ext4_iomap_begin() and thus simplify
ext4_dax_fault(). It also provides us proper retries in case of ENOSPC.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Currently ->iomap_begin() handler is called with entry lock held. If the
filesystem held any locks between ->iomap_begin() and ->iomap_end()
(such as ext4 which will want to hold transaction open), this would cause
lock inversion with the iomap_apply() from standard IO path which first
calls ->iomap_begin() and only then calls ->actor() callback which grabs
entry locks for DAX (if it faults when copying from/to user provided
buffers).

Fix the problem by nesting grabbing of entry lock inside ->iomap_begin()
- ->iomap_end() pair.
Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The only case when we do not finish the page fault completely is when we
are loading hole pages into a radix tree. Avoid this special case and
finish the fault in that case as well inside the DAX fault handler. It
will allow us for easier iomap handling.
Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Currently dax_iomap_rw() takes care of invalidating page tables and
evicting hole pages from the radix tree when write(2) to the file
happens. This invalidation is only necessary when there is some block
allocation resulting from write(2). Furthermore in current place the
invalidation is racy wrt page fault instantiating a hole page just after
we have invalidated it.

So perform the page invalidation inside dax_iomap_actor() where we can
do it only when really necessary and after blocks have been allocated so
nobody will be instantiating new hole pages anymore.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Currently invalidate_inode_pages2_range() and invalidate_mapping_pages()
just delete all exceptional radix tree entries they find. For DAX this
is not desirable as we track cache dirtiness in these entries and when
they are evicted, we may not flush caches although it is necessary. This
can for example manifest when we write to the same block both via mmap
and via write(2) (to different offsets) and fsync(2) then does not
properly flush CPU caches when modification via write(2) was the last
one.

Create appropriate DAX functions to handle invalidation of DAX entries
for invalidate_inode_pages2_range() and invalidate_mapping_pages() and
wire them up into the corresponding mm functions.
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

So far we did not return BH_New buffers from ext2_get_blocks() when we
allocated and zeroed-out a block for DAX inode to avoid racy zeroing in
DAX code. This zeroing is gone these days so we can remove the
workaround.
Reviewed-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

No point in going through loops and hoops instead of just comparing the
values.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

ktime_set(S,N) was required for the timespec storage type and is still
useful for situations where a Seconds and Nanoseconds part of a time value
needs to be converted. For anything where the Seconds argument is 0, this
is pointless and can be replaced with a simple assignment.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

ktime is a union because the initial implementation stored the time in
scalar nanoseconds on 64 bit machine and in a endianess optimized timespec
variant for 32bit machines. The Y2038 cleanup removed the timespec variant
and switched everything to scalar nanoseconds. The union remained, but
become completely pointless.

Get rid of the union and just keep ktime_t as simple typedef of type s64.

The conversion was done with coccinelle and some manual mopping up.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sparse says:

    fs/ufs/inode.c:1195:6: warning: symbol 'ufs_truncate_blocks' was not declared. Should it be static?

Note that the forward declaration in the file is already marked static.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If you have a process that has set itself to be non-dumpable, and it
then undergoes exec(2), any CLOEXEC file descriptors it has open are
"exposed" during a race window between the dumpable flags of the process
being reset for exec(2) and CLOEXEC being applied to the file
descriptors. This can be exploited by a process by attempting to access
/proc/<pid>/fd/... during this window, without requiring CAP_SYS_PTRACE.

The race in question is after set_dumpable has been (for get_link,
though the trace is basically the same for readlink):

[vfs]
-> proc_pid_link_inode_operations.get_link
   -> proc_pid_get_link
      -> proc_fd_access_allowed
         -> ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);

Which will return 0, during the race window and CLOEXEC file descriptors
will still be open during this window because do_close_on_exec has not
been called yet. As a result, the ordering of these calls should be
reversed to avoid this race window.

This is of particular concern to container runtimes, where joining a
PID namespace with file descriptors referring to the host filesystem
can result in security issues (since PRCTL_SET_DUMPABLE doesn't protect
against access of CLOEXEC file descriptors -- file descriptors which may
reference filesystem objects the container shouldn't have access to).

Cc: dev@opencontainers.org
Cc: <stable@vger.kernel.org> # v3.2+
Reported-by: NMichael Crosby <crosbymichael@gmail.com>
Signed-off-by: NAleksa Sarai <asarai@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

If kernfs file is empty on a first read, successive read operations
using the same file descriptor will return no data, even when data is
available. Default kernfs 'seq_next' implementation advances iterator
position even when next object is not there. Kernfs 'seq_start' for
following requests will not return iterator as position is already on
the second object.

This defect doesn't allow to monitor badblocks sysfs files from MD raid.
They are initially empty but if data appears at some stage, userspace is
not able to read it.
Signed-off-by: NTomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Strengthen the checking of pos/len vs. i_size, clarify the return values
for the clone prep function, and remove pointless code.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and fix the minor buglet in compat io_submit() - native one
kills ioctx as cleanup when put_user() fails.  Get rid of
bogus compat_... in !CONFIG_AIO case, while we are at it - they
should simply fail with ENOSYS, same as for native counterparts.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Implement mandatory export_operations, so it is possible to export befs via
nfs.
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Removing all trailing whitespaces in befs.

I was skeptic about tainting the history with this, but whitespace changes
can be ignored by using 'git blame -w' and 'git log -w'.
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

No idea why some comments have signatures. These predate git. Removing them
since they add noise and no information.
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fixing checkpatch.pl issues in befs header files:
WARNING: Missing a blank line after declarations
+       befs_inode_addr iaddr;
+       iaddr.allocation_group = blockno >> BEFS_SB(sb)->ag_shift;

WARNING: space prohibited between function name and open parenthesis '('
+       return BEFS_SB(sb)->block_size / sizeof (befs_disk_inode_addr);

ERROR: "foo * bar" should be "foo *bar"
+                   const char *key, befs_off_t * value);

ERROR: Macros with complex values should be enclosed in parentheses
+#define PACKED __attribute__ ((__packed__))
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fix the following type of checkpatch.pl issues:
WARNING: line over 80 characters
+static struct dentry *befs_lookup(struct inode *, struct dentry *, unsigned int);

ERROR: code indent should use tabs where possible
+        if (!bi)$

WARNING: please, no spaces at the start of a line
+        if (!bi)$

WARNING: labels should not be indented
+      unacquire_bh:

WARNING: space prohibited between function name and open parenthesis '('
+                                             sizeof (struct befs_inode_info),

WARNING: braces {} are not necessary for single statement blocks
+       if (!*out) {
+               return -ENOMEM;
+       }

WARNING: Block comments use a trailing */ on a separate line
+        * in special cases */

WARNING: Missing a blank line after declarations
+               int token;
+               if (!*p)

ERROR: do not use assignment in if condition
+       if (!(bh = sb_bread(sb, sb_block))) {

ERROR: space prohibited after that open parenthesis '('
+       if( befs_sb->num_blocks > ~((sector_t)0) ) {

ERROR: space prohibited before that close parenthesis ')'
+       if( befs_sb->num_blocks > ~((sector_t)0) ) {

ERROR: space required before the open parenthesis '('
+       if( befs_sb->num_blocks > ~((sector_t)0) ) {
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fixing the two following checkpatch.pl issues:
ERROR: trailing whitespace
+ * Based on portions of file.c and inode.c $

WARNING: labels should not be indented
+      error:
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fixing the following checkpatch.pl errors and warning:
ERROR: trailing whitespace
+ * $

WARNING: Block comments use * on subsequent lines
+/*
+       Validates the correctness of the befs inode

ERROR: "foo * bar" should be "foo *bar"
+befs_check_inode(struct super_block *sb, befs_inode * raw_inode,
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Fix all checkpatch.pl errors and warnings in debug.c:
ERROR: trailing whitespace
+ * $

WARNING: Missing a blank line after declarations
+       va_list args;
+       va_start(args, fmt);

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_inode(const struct super_block *sb, befs_inode * inode)

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_super_block(const struct super_block *sb, befs_super_block * sup)

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_small_data(const struct super_block *sb, befs_small_data * sd)

WARNING: line over 80 characters
+befs_dump_index_entry(const struct super_block *sb, befs_disk_btree_super * super)

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_index_entry(const struct super_block *sb, befs_disk_btree_super * super)

ERROR: "foo * bar" should be "foo *bar"
+befs_dump_index_node(const struct super_block *sb, befs_btree_nodehead * node)
Signed-off-by: NLuis de Bethencourt <luisbg@osg.samsung.com>

Commit 8924feff ("splice: lift pipe_lock out of splice_to_pipe()")
caused a regression when there were no more readers left on a pipe that
was being spliced into: rather than the expected SIGPIPE and -EPIPE
return value, the writer would end up waiting forever for space to free
up (which obviously was not going to happen with no readers around).

Fixes: 8924feff ("splice: lift pipe_lock out of splice_to_pipe()")
Reported-and-tested-by: NAndreas Schwab <schwab@linux-m68k.org>
Debugged-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org   # v4.9
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If our DELEGRETURN RPC call is rejected with an EACCES call, then we should
remove the GETATTR call from the compound RPC and retry.
This could potentially happen when there is a conflict between an
ACL denying attribute reads and our use of SP4_MACH_CRED.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If our CLOSE RPC call is rejected with an EACCES call, then we should
remove the GETATTR call from the compound RPC and retry.
This could potentially happen when there is a conflict between an
ACL denying attribute reads and our use of SP4_MACH_CRED.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

In order to benefit from the DENY share lock protection, we should
put the GETATTR operation before the CLOSE. Otherwise, we might race
with a Windows machine that thinks it is now safe to modify the file.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If we're downgrading from a READ+WRITE mode to a READ-only mode, then
ask for cache consistency attributes so that we avoid the revalidation
in nfs_close_context()

Fixes: 3947b74d ("NFSv4: Don't request a GETATTR on open_downgrade.")
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The NFS_INO_REVAL_FORCED flag now really only has meaning for the
case when we've just been handed a delegation for a file that was already
cached, and we're unsure about that cache.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the client holds no more writeable open state, and does not hold a
write delegation, then send a layoutreturn as part of the OPEN_DOWNGRADE.

We do this only for writes, since some layout drivers may require you to
also hold a read layout if you are doing a R/W workload.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

While we do not need to return the RW layout when downgrading from a
read/write open state to read-only, we might want to do so in order
to reduce the burden on the metadataserver so that it does not need
to check for changed data when responding to GETATTR requests.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When an NFS4ERR_BAD_SEQID is received the open-owner is removed from
the ->state_owners rbtree so that it will no longer be used.

If any stateids attached to this open-owner are still in use, and if a
request using one gets an NFS4ERR_BAD_STATEID reply, this can for bad.

The state is marked as needing recovery and the nfs4_state_manager()
is scheduled to clean up.  nfs4_state_manager() finds states to be
recovered by walking the state_owners rbtree.  As the open-owner is
not in the rbtree, the bad state is not found so nfs4_state_manager()
completes having done nothing.  The request is then retried, with a
predicatable result (indefinite retries).

If the stateid is for a delegation, this open_owner will be used
to open files when the delegation is returned.  For that to work,
a new open-owner needs to be presented to the server.

This patch changes NFS4ERR_BAD_SEQID handling to leave the open-owner
in the rbtree but updates the 'create_time' so it looks like a new
open-owner.  With this the indefinite retries no longer happen.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>