732 Commits

Author SHA1 Message Date
Miklos Szeredi
f428884456 ovl: decide if revalidate needed on a per-dentry basis
Allow completely skipping ->revalidate() on a per-dentry basis, in case the
underlying layers used for a dentry do not themselves have ->revalidate().

E.g. negative overlay dentry has no underlying layers, hence revalidate is
unnecessary.  Or if lower layer is remote but overlay dentry is pure-upper,
then can skip revalidate.

The following places need to update whether the dentry needs revalidate or
not:

 - fill-super (root dentry)
 - lookup
 - create
 - fh_to_dentry

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-17 15:04:22 +01:00
Miklos Szeredi
7925dad839 ovl: separate detection of remote upper layer from stacked overlay
Following patch will allow remote as upper layer, but not overlay stacked
on upper layer.  Separate the two concepts.

This patch is doesn't change behavior.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-17 15:04:22 +01:00
Miklos Szeredi
3bb7df928a ovl: restructure dentry revalidation
Use a common loop for plain and weak revalidation.  This will aid doing
revalidation on upper layer.

This patch doesn't change behavior.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-17 15:04:22 +01:00
Miklos Szeredi
c61ca55725 ovl: ignore failure to copy up unknown xattrs
This issue came up with NFSv4 as the lower layer, which generates
"system.nfs4_acl" xattrs (even for plain old unix permissions).  Prior to
this patch this prevented copy-up from succeeding.

The overlayfs permission model mandates that permissions are checked
locally for the task and remotely for the mounter(*).  NFS4 ACLs are not
supported by the Linux kernel currently, hence they cannot be enforced
locally.  Which means it is indifferent whether this attribute is copied or
not.

Generalize this to any xattr that is not used in access checking (i.e. it's
not a POSIX ACL and not in the "security." namespace).

Incidentally, best effort copying of xattrs seems to also be the behavior
of "cp -a", which is what overlayfs tries to mimic.

(*) Documentation/filesystems/overlayfs.txt#Permission model

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-17 15:04:22 +01:00
Amir Goldstein
62c832ed4e ovl: simplify i_ino initialization
Move i_ino initialization to ovl_inode_init() to avoid the dance of setting
i_ino in ovl_fill_inode() sometimes on the first call and sometimes on the
seconds call.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-17 15:04:22 +01:00
Amir Goldstein
2effc5c25d ovl: factor out helper ovl_get_root()
Allocates and initializes the root dentry and inode.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-17 15:04:22 +01:00
Amir Goldstein
735c907d7b ovl: fix out of date comment and unreachable code
ovl_inode_update() is no longer called from create object code path.

Fixes: 01b39dcc9568 ("ovl: use inode_insert5() to hash a newly...")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-17 15:04:21 +01:00
Amir Goldstein
300b124fcf ovl: fix value of i_ino for lower hardlink corner case
Commit 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more
cases"), relaxed the condition nfs_export=on in order to set the value of
i_ino to xino map of real ino.

Specifically, it also relaxed the pre-condition that index=on for
consistent i_ino. This opened the corner case of lower hardlink in
ovl_get_inode(), which calls ovl_fill_inode() with ino=0 and then
ovl_init_inode() is called to set i_ino to lower real ino without the xino
mapping.

Pass the correct values of ino;fsid in this case to ovl_fill_inode(), so it
can initialize i_ino correctly.

Fixes: 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more ...")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-17 15:04:21 +01:00
Miklos Szeredi
c853680453 ovl: fix lockdep warning for async write
Lockdep reports "WARNING: lock held when returning to user space!" due to
async write holding freeze lock over the write.  Apparently aio.c already
deals with this by lying to lockdep about the state of the lock.

Do the same here.  No need to check for S_IFREG() here since these file ops
are regular-only.

Reported-by: syzbot+9331a354f4f624a52a55@syzkaller.appspotmail.com
Fixes: 2406a307ac7d ("ovl: implement async IO routines")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-13 15:53:06 +01:00
Amir Goldstein
53afcd310e ovl: fix some xino configurations
Fix up two bugs in the coversion to xino_mode:
1. xino=off does not always end up in disabled mode
2. xino=auto on 32bit arch should end up in disabled mode

Take a proactive approach to disabling xino on 32bit kernel:
1. Disable XINO_AUTO config during build time
2. Disable xino with a warning on mount time

As a by product, xino=on on 32bit arch also ends up in disabled mode.
We never intended to enable xino on 32bit arch and this will make the
rest of the logic simpler.

Fixes: 0f831ec85eda ("ovl: simplify ovl_same_sb() helper")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-13 15:53:06 +01:00
Amir Goldstein
531d3040bc ovl: fix lock in ovl_llseek()
ovl_inode_lock() is interruptible. When inode_lock() in ovl_llseek()
was replaced with ovl_inode_lock(), we did not add a check for error.

Fix this by making ovl_inode_lock() uninterruptible and change the
existing call sites to use an _interruptible variant.

Reported-by: syzbot+66a9752fa927f745385e@syzkaller.appspotmail.com
Fixes: b1f9d3858f72 ("ovl: use ovl_inode_lock in ovl_llseek()")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-12 16:38:10 +01:00
Miklos Szeredi
a4ac9d45c0 ovl: fix lseek overflow on 32bit
ovl_lseek() is using ssize_t to return the value from vfs_llseek().  On a
32-bit kernel ssize_t is a 32-bit signed int, which overflows above 2 GB.

Assign the return value of vfs_llseek() to loff_t to fix this.

Reported-by: Boris Gjenero <boris.gjenero@gmail.com>
Fixes: 9e46b840c705 ("ovl: support stacked SEEK_HOLE/SEEK_DATA")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-02-03 11:41:53 +01:00
Murphy Zhou
1a980b8cbf ovl: add splice file read write helper
Now overlayfs falls back to use default file splice read
and write, which is not compatiple with overlayfs, returning
EFAULT. xfstests generic/591 can reproduce part of this.

Tested this patch with xfstests auto group tests.

Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24 16:28:15 +01:00
Jiufei Xue
2406a307ac ovl: implement async IO routines
A performance regression was observed since linux v4.19 with aio test using
fio with iodepth 128 on overlayfs.  The queue depth of the device was
always 1 which is unexpected.

After investigation, it was found that commit 16914e6fc7e1 ("ovl: add
ovl_read_iter()") and commit 2a92e07edc5e ("ovl: add ovl_write_iter()")
resulted in vfs_iter_{read,write} being called on underlying filesystem,
which always results in syncronous IO.

Implement async IO for stacked reading and writing.  This resolves the
performance regresion.

This is implemented by allocating a new kiocb for submitting the AIO
request on the underlying filesystem.  When the request is completed, the
new kiocb is freed and the completion callback is called on the original
iocb.

Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24 09:46:46 +01:00
Miklos Szeredi
1346416564 ovl: layer is const
The ovl_layer struct is never modified except at initialization.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24 09:46:45 +01:00
Amir Goldstein
b7bf9908e1 ovl: fix corner case of non-constant st_dev;st_ino
On non-samefs overlay without xino, non pure upper inodes should use a
pseudo_dev assigned to each unique lower fs, but if lower layer is on the
same fs and upper layer, it has no pseudo_dev assigned.

In this overlay layers setup:
 - two filesystems, A and B
 - upper layer is on A
 - lower layer 1 is also on A
 - lower layer 2 is on B

Non pure upper overlay inode, whose origin is in layer 1 will have the
st_dev;st_ino values of the real lower inode before copy up and the
st_dev;st_ino values of the real upper inode after copy up.

Fix this inconsitency by assigning a unique pseudo_dev also for upper fs,
that will be used as st_dev value along with the lower inode st_dev for
overlay inodes in the case above.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24 09:46:45 +01:00
Amir Goldstein
1b81dddd35 ovl: fix corner case of conflicting lower layer uuid
This fixes ovl_lower_uuid_ok() to correctly detect the corner case:
 - two filesystems, A and B, both have null uuid
 - upper layer is on A
 - lower layer 1 is also on A
 - lower layer 2 is on B

In this case, bad_uuid would not have been set for B, because the check
only involved the list of lower fs.  Hence we'll try to decode a layer 2
origin on layer 1 and fail.

We check for conflicting (and null) uuid among all lower layers, including
those layers that are on the same fs as the upper layer.

Reported-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24 09:46:45 +01:00
Amir Goldstein
07f1e59637 ovl: generalize the lower_fs[] array
Rename lower_fs[] array to fs[], extend its size by one and use index fsid
(instead of fsid-1) to access the fs[] array.

Initialize fs[0] with upper fs values. fsid 0 is reserved even with lower
only overlay, so fs[0] remains null in this case.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24 09:46:45 +01:00
Amir Goldstein
0f831ec85e ovl: simplify ovl_same_sb() helper
No code uses the sb returned from this helper, so make it retrun a boolean
and rename it to ovl_same_fs().

The xino mode is irrelevant when all layers are on same fs, so instead of
describing samefs with mode OVL_XINO_OFF, use a new xino_mode state, which
is 0 in the case of samefs, -1 in the case of xino=off and > 0 with xino
enabled.

Create a new helper ovl_same_dev(), to use instead of the common check for
(ovl_same_fs() || xinobits).

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24 09:46:45 +01:00
Amir Goldstein
94375f9d51 ovl: generalize the lower_layers[] array
Rename lower_layers[] array to layers[], extend its size by one and
initialize layers[0] with upper layer values.  Lower layers are now
addressed with index 1..numlower.  layers[0] is reserved even with lower
only overlay.

[SzM: replace ofs->numlower with ofs->numlayer, the latter's value is
incremented by one]

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22 20:11:41 +01:00
Chengguang Xu
b504c6540d ovl: improving copy-up efficiency for big sparse file
Current copy-up is not efficient for big sparse file,
It's not only slow but also wasting more disk space
when the target lower file has huge hole inside.
This patch tries to recognize file hole and skip it
during copy-up.

Detail logic of hole detection as below:
When we detect next data position is larger than current
position we will skip that hole, otherwise we copy
data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually,
it may not recognize all kind of holes and sometimes
only skips partial of hole area. However, it will be
enough for most of the use cases.

Additionally, this optimization relies on lseek(2)
SEEK_DATA implementation, so for some specific
filesystems which do not support this feature
will behave as before on copy-up.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22 20:11:41 +01:00
Amir Goldstein
b1f9d3858f ovl: use ovl_inode_lock in ovl_llseek()
In ovl_llseek() we use the overlay inode rwsem to protect against
concurrent modifications to real file f_pos, because we copy the overlay
file f_pos to/from the real file f_pos.

This caused a lockdep warning of locking order violation when the
ovl_llseek() operation was called on a lower nested overlay layer while the
upper layer fs sb_writers is held (with patch improving copy-up efficiency
for big sparse file).

Use the internal ovl_inode_lock() instead of the overlay inode rwsem in
those cases. It is meant to be used for protecting against concurrent
changes to overlay inode internal state changes.

The locking order rules are documented to explain this case.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22 20:11:41 +01:00
lijiazi
1bd0a3aea4 ovl: use pr_fmt auto generate prefix
Use pr_fmt auto generate "overlayfs: " prefix.

Signed-off-by: lijiazi <lijiazi@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22 20:11:41 +01:00
Amir Goldstein
4c37e71b71 ovl: fix wrong WARN_ON() in ovl_cache_update_ino()
The WARN_ON() that child entry is always on overlay st_dev became wrong
when we allowed this function to update d_ino in non-samefs setup with xino
enabled.

It is not true in case of xino bits overflow on a non-dir inode.  Leave the
WARN_ON() only for directories, where assertion is still true.

Fixes: adbf4f7ea834 ("ovl: consistent d_ino for non-samefs with xino")
Cc: <stable@vger.kernel.org> # v4.17+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22 20:11:41 +01:00
Linus Torvalds
81c64b0bd0 overlayfs fixes for 5.5-rc2
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Merge tag 'ovl-fixes-5.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs fixes from Miklos Szeredi:
 "Fix some bugs and documentation"

* tag 'ovl-fixes-5.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  docs: filesystems: overlayfs: Fix restview warnings
  docs: filesystems: overlayfs: Rename overlayfs.txt to .rst
  ovl: relax WARN_ON() on rename to self
  ovl: fix corner case of non-unique st_dev;st_ino
  ovl: don't use a temp buf for encoding real fh
  ovl: make sure that real fid is 32bit aligned in memory
  ovl: fix lookup failure on multi lower squashfs
2019-12-14 11:13:54 -08:00
Amir Goldstein
6889ee5a53 ovl: relax WARN_ON() on rename to self
In ovl_rename(), if new upper is hardlinked to old upper underneath
overlayfs before upper dirs are locked, user will get an ESTALE error
and a WARN_ON will be printed.

Changes to underlying layers while overlayfs is mounted may result in
unexpected behavior, but it shouldn't crash the kernel and it shouldn't
trigger WARN_ON() either, so relax this WARN_ON().

Reported-by: syzbot+bb1836a212e69f8e201a@syzkaller.appspotmail.com
Fixes: 804032fabb3b ("ovl: don't check rename to self")
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-12-10 16:00:55 +01:00
Amir Goldstein
9c6d8f13e9 ovl: fix corner case of non-unique st_dev;st_ino
On non-samefs overlay without xino, non pure upper inodes should use a
pseudo_dev assigned to each unique lower fs and pure upper inodes use the
real upper st_dev.

It is fine for an overlay pure upper inode to use the same st_dev;st_ino
values as the real upper inode, because the content of those two different
filesystem objects is always the same.

In this case, however:
 - two filesystems, A and B
 - upper layer is on A
 - lower layer 1 is also on A
 - lower layer 2 is on B

Non pure upper overlay inode, whose origin is in layer 1 will have the same
st_dev;st_ino values as the real lower inode. This may result with a false
positive results of 'diff' between the real lower and copied up overlay
inode.

Fix this by using the upper st_dev;st_ino values in this case.  This breaks
the property of constant st_dev;st_ino across copy up of this case. This
breakage will be fixed by a later patch.

Fixes: 5148626b806a ("ovl: allocate anon bdev per unique lower fs")
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-12-10 16:00:55 +01:00
Amir Goldstein
ec7bbb53d3 ovl: don't use a temp buf for encoding real fh
We can allocate maximum fh size and encode into it directly.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-12-10 16:00:55 +01:00
Amir Goldstein
cbe7fba8ed ovl: make sure that real fid is 32bit aligned in memory
Seprate on-disk encoding from in-memory and on-wire resresentation
of overlay file handle.

In-memory and on-wire we only ever pass around pointers to struct
ovl_fh, which encapsulates at offset 3 the on-disk format struct
ovl_fb. struct ovl_fb encapsulates at offset 21 the real file handle.
That makes sure that the real file handle is always 32bit aligned
in-memory when passed down to the underlying filesystem.

On-disk format remains the same and store/load are done into
correctly aligned buffer.

New nfs exported file handles are exported with aligned real fid.
Old nfs file handles are copied to an aligned buffer before being
decoded.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-12-10 16:00:55 +01:00
Amir Goldstein
7e63c87fc2 ovl: fix lookup failure on multi lower squashfs
In the past, overlayfs required that lower fs have non null uuid in
order to support nfs export and decode copy up origin file handles.

Commit 9df085f3c9a2 ("ovl: relax requirement for non null uuid of
lower fs") relaxed this requirement for nfs export support, as long
as uuid (even if null) is unique among all lower fs.

However, said commit unintentionally also relaxed the non null uuid
requirement for decoding copy up origin file handles, regardless of
the unique uuid requirement.

Amend this mistake by disabling decoding of copy up origin file handle
from lower fs with a conflicting uuid.

We still encode copy up origin file handles from those fs, because
file handles like those already exist in the wild and because they
might provide useful information in the future.

There is an unhandled corner case described by Miklos this way:
- two filesystems, A and B, both have null uuid
- upper layer is on A
- lower layer 1 is also on A
- lower layer 2 is on B

In this case bad_uuid won't be set for B, because the check only
involves the list of lower fs.  Hence we'll try to decode a layer 2
origin on layer 1 and fail.

We will deal with this corner case later.

Reported-by: Colin Ian King <colin.king@canonical.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/lkml/20191106234301.283006-1-colin.king@canonical.com/
Fixes: 9df085f3c9a2 ("ovl: relax requirement for non null uuid ...")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-12-10 16:00:55 +01:00
Al Viro
6c2d4798a8 new helper: lookup_positive_unlocked()
Most of the callers of lookup_one_len_unlocked() treat negatives are
ERR_PTR(-ENOENT).  Provide a helper that would do just that.  Note
that a pinned positive dentry remains positive - it's ->d_inode is
stable, etc.; a pinned _negative_ dentry can become positive at any
point as long as you are not holding its parent at least shared.
So using lookup_one_len_unlocked() needs to be careful;
lookup_positive_unlocked() is safer and that's what the callers
end up open-coding anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-15 13:49:04 -05:00
Mark Salyzyn
5c2e9f346b ovl: filter of trusted xattr results in audit
When filtering xattr list for reading, presence of trusted xattr
results in a security audit log.  However, if there is other content
no errno will be set, and if there isn't, the errno will be -ENODATA
and not -EPERM as is usually associated with a lack of capability.
The check does not block the request to list the xattrs present.

Switch to ns_capable_noaudit to reflect a more appropriate check.

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: linux-security-module@vger.kernel.org
Cc: kernel-team@android.com
Cc: stable@vger.kernel.org # v3.18+
Fixes: a082c6f680da ("ovl: filter trusted xattr for non-admin")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-11 16:11:45 +02:00
Ding Xiang
97f024b917 ovl: Fix dereferencing possible ERR_PTR()
if ovl_encode_real_fh() fails, no memory was allocated
and the error in the error-valued pointer should be returned.

Fixes: 9b6faee07470 ("ovl: check ERR_PTR() return value from ovl_encode_fh()")
Signed-off-by: Ding Xiang <dingxiang@cmss.chinamobile.com>
Cc: <stable@vger.kernel.org> # v4.16+
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-11 16:11:45 +02:00
Amir Goldstein
0be0bfd2de ovl: fix regression caused by overlapping layers detection
Once upon a time, commit 2cac0c00a6cd ("ovl: get exclusive ownership on
upper/work dirs") in v4.13 added some sanity checks on overlayfs layers.
This change caused a docker regression. The root cause was mount leaks
by docker, which as far as I know, still exist.

To mitigate the regression, commit 85fdee1eef1a ("ovl: fix regression
caused by exclusive upper/work dir protection") in v4.14 turned the
mount errors into warnings for the default index=off configuration.

Recently, commit 146d62e5a586 ("ovl: detect overlapping layers") in
v5.2, re-introduced exclusive upper/work dir checks regardless of
index=off configuration.

This changes the status quo and mount leak related bug reports have
started to re-surface. Restore the status quo to fix the regressions.
To clarify, index=off does NOT relax overlapping layers check for this
ovelayfs mount. index=off only relaxes exclusive upper/work dir checks
with another overlayfs mount.

To cover the part of overlapping layers detection that used the
exclusive upper/work dir checks to detect overlap with self upper/work
dir, add a trap also on the work base dir.

Link: https://github.com/moby/moby/issues/34672
Link: https://lore.kernel.org/linux-fsdevel/20171006121405.GA32700@veci.piliscsaba.szeredi.hu/
Link: https://github.com/containers/libpod/issues/3540
Fixes: 146d62e5a586 ("ovl: detect overlapping layers")
Cc: <stable@vger.kernel.org> # v4.19+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Tested-by: Colin Walters <walters@verbum.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-07-16 13:23:40 +02:00
Linus Torvalds
c884d8ac7f SPDX update for 5.2-rc6
Another round of SPDX updates for 5.2-rc6
 
 Here is what I am guessing is going to be the last "big" SPDX update for
 5.2.  It contains all of the remaining GPLv2 and GPLv2+ updates that
 were "easy" to determine by pattern matching.  The ones after this are
 going to be a bit more difficult and the people on the spdx list will be
 discussing them on a case-by-case basis now.
 
 Another 5000+ files are fixed up, so our overall totals are:
 	Files checked:            64545
 	Files with SPDX:          45529
 
 Compared to the 5.1 kernel which was:
 	Files checked:            63848
 	Files with SPDX:          22576
 This is a huge improvement.
 
 Also, we deleted another 20000 lines of boilerplate license crud, always
 nice to see in a diffstat.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'spdx-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx

Pull still more SPDX updates from Greg KH:
 "Another round of SPDX updates for 5.2-rc6

  Here is what I am guessing is going to be the last "big" SPDX update
  for 5.2. It contains all of the remaining GPLv2 and GPLv2+ updates
  that were "easy" to determine by pattern matching. The ones after this
  are going to be a bit more difficult and the people on the spdx list
  will be discussing them on a case-by-case basis now.

  Another 5000+ files are fixed up, so our overall totals are:
	Files checked:            64545
	Files with SPDX:          45529

  Compared to the 5.1 kernel which was:
	Files checked:            63848
	Files with SPDX:          22576

  This is a huge improvement.

  Also, we deleted another 20000 lines of boilerplate license crud,
  always nice to see in a diffstat"

* tag 'spdx-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: (65 commits)
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 507
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 506
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 503
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 502
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 501
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 498
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 496
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 495
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 491
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 490
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 489
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 488
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 487
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 486
  treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 485
  ...
2019-06-21 09:58:42 -07:00
Thomas Gleixner
d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00
Amir Goldstein
6dde1e42f4 ovl: make i_ino consistent with st_ino in more cases
Relax the condition that overlayfs supports nfs export, to require
that i_ino is consistent with st_ino/d_ino.

It is enough to require that st_ino and d_ino are consistent.

This fixes the failure of xfstest generic/504, due to mismatch of
st_ino to inode number in the output of /proc/locks.

Fixes: 12574a9f4c9c ("ovl: consistent i_ino for non-samefs with xino")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-06-19 09:04:19 +02:00
Nicolas Schier
253e748339 ovl: fix typo in MODULE_PARM_DESC
Change first argument to MODULE_PARM_DESC() calls, that each of them
matched the actual module parameter name.  The matching results in
changing (the 'parm' section from) the output of `modinfo overlay` from:

    parm: ovl_check_copy_up:Obsolete; does nothing
    parm: redirect_max:ushort
    parm: ovl_redirect_max:Maximum length of absolute redirect xattr value
    parm: redirect_dir:bool
    parm: ovl_redirect_dir_def:Default to on or off for the redirect_dir feature
    parm: redirect_always_follow:bool
    parm: ovl_redirect_always_follow:Follow redirects even if redirect_dir feature is turned off
    parm: index:bool
    parm: ovl_index_def:Default to on or off for the inodes index feature
    parm: nfs_export:bool
    parm: ovl_nfs_export_def:Default to on or off for the NFS export feature
    parm: xino_auto:bool
    parm: ovl_xino_auto_def:Auto enable xino feature
    parm: metacopy:bool
    parm: ovl_metacopy_def:Default to on or off for the metadata only copy up feature

into:

    parm: check_copy_up:Obsolete; does nothing
    parm: redirect_max:Maximum length of absolute redirect xattr value (ushort)
    parm: redirect_dir:Default to on or off for the redirect_dir feature (bool)
    parm: redirect_always_follow:Follow redirects even if redirect_dir feature is turned off (bool)
    parm: index:Default to on or off for the inodes index feature (bool)
    parm: nfs_export:Default to on or off for the NFS export feature (bool)
    parm: xino_auto:Auto enable xino feature (bool)
    parm: metacopy:Default to on or off for the metadata only copy up feature (bool)

Signed-off-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-06-18 15:06:16 +02:00
Arnd Bergmann
1dac6f5b0e ovl: fix bogus -Wmaybe-unitialized warning
gcc gets a bit confused by the logic in ovl_setup_trap() and
can't figure out whether the local 'trap' variable in the caller
was initialized or not:

fs/overlayfs/super.c: In function 'ovl_fill_super':
fs/overlayfs/super.c:1333:4: error: 'trap' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    iput(trap);
    ^~~~~~~~~~
fs/overlayfs/super.c:1312:17: note: 'trap' was declared here

Reword slightly to make it easier for the compiler to understand.

Fixes: 146d62e5a586 ("ovl: detect overlapping layers")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-06-18 15:06:16 +02:00
Miklos Szeredi
9179c21dc6 ovl: don't fail with disconnected lower NFS
NFS mounts can be disconnected from fs root.  Don't fail the overlapping
layer check because of this.

The check is not authoritative anyway, since topology can change during or
after the check.

Reported-by: Antti Antinoja <antti@fennosys.fi> 
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 146d62e5a586 ("ovl: detect overlapping layers")
2019-06-18 15:06:16 +02:00
Amir Goldstein
941d935ac7 ovl: fix wrong flags check in FS_IOC_FS[SG]ETXATTR ioctls
The ioctl argument was parsed as the wrong type.

Fixes: b21d9c435f93 ("ovl: support the FS_IOC_FS[SG]ETXATTR ioctls")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-06-11 17:17:41 +02:00
Amir Goldstein
146d62e5a5 ovl: detect overlapping layers
Overlapping overlay layers are not supported and can cause unexpected
behavior, but overlayfs does not currently check or warn about these
configurations.

User is not supposed to specify the same directory for upper and
lower dirs or for different lower layers and user is not supposed to
specify directories that are descendants of each other for overlay
layers, but that is exactly what this zysbot repro did:

    https://syzkaller.appspot.com/x/repro.syz?x=12c7a94f400000

Moving layer root directories into other layers while overlayfs
is mounted could also result in unexpected behavior.

This commit places "traps" in the overlay inode hash table.
Those traps are dummy overlay inodes that are hashed by the layers
root inodes.

On mount, the hash table trap entries are used to verify that overlay
layers are not overlapping.  While at it, we also verify that overlay
layers are not overlapping with directories "in-use" by other overlay
instances as upperdir/workdir.

On lookup, the trap entries are used to verify that overlay layers
root inodes have not been moved into other layers after mount.

Some examples:

$ ./run --ov --samefs -s
...
( mkdir -p base/upper/0/u base/upper/0/w base/lower lower upper mnt
  mount -o bind base/lower lower
  mount -o bind base/upper upper
  mount -t overlay none mnt ...
        -o lowerdir=lower,upperdir=upper/0/u,workdir=upper/0/w)

$ umount mnt
$ mount -t overlay none mnt ...
        -o lowerdir=base,upperdir=upper/0/u,workdir=upper/0/w

  [   94.434900] overlayfs: overlapping upperdir path
  mount: mount overlay on mnt failed: Too many levels of symbolic links

$ mount -t overlay none mnt ...
        -o lowerdir=upper/0/u,upperdir=upper/0/u,workdir=upper/0/w

  [  151.350132] overlayfs: conflicting lowerdir path
  mount: none is already mounted or mnt busy

$ mount -t overlay none mnt ...
        -o lowerdir=lower:lower/a,upperdir=upper/0/u,workdir=upper/0/w

  [  201.205045] overlayfs: overlapping lowerdir path
  mount: mount overlay on mnt failed: Too many levels of symbolic links

$ mount -t overlay none mnt ...
        -o lowerdir=lower,upperdir=upper/0/u,workdir=upper/0/w
$ mv base/upper/0/ base/lower/
$ find mnt/0
  mnt/0
  mnt/0/w
  find: 'mnt/0/w/work': Too many levels of symbolic links
  find: 'mnt/0/u': Too many levels of symbolic links

Reported-by: syzbot+9c69c282adc4edd2b540@syzkaller.appspotmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-29 13:03:37 +02:00
Amir Goldstein
b21d9c435f ovl: support the FS_IOC_FS[SG]ETXATTR ioctls
They are the extended version of FS_IOC_FS[SG]ETFLAGS ioctls.
xfs_io -c "chattr <flags>" uses the new ioctls for setting flags.

This used to work in kernel pre v4.19, before stacked file ops
introduced the ovl_ioctl whitelist.

Reported-by: Dave Chinner <david@fromorbit.com>
Fixes: d1d04ef8572b ("ovl: stack file ops")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-27 10:03:10 +02:00
Thomas Gleixner
ec8f24b7fa treewide: Add SPDX license identifier - Makefile/Kconfig
Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:46 +02:00
Linus Torvalds
7e9890a350 overlayfs update for 5.2
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Merge tag 'ovl-update-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs update from Miklos Szeredi:
 "Just bug fixes in this small update"

* tag 'ovl-update-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: relax WARN_ON() for overlapping layers use case
  ovl: check the capability before cred overridden
  ovl: do not generate duplicate fsnotify events for "fake" path
  ovl: support stacked SEEK_HOLE/SEEK_DATA
  ovl: fix missing upper fs freeze protection on copy up for ioctl
2019-05-14 09:02:14 -07:00
Amir Goldstein
acf3062a7e ovl: relax WARN_ON() for overlapping layers use case
This nasty little syzbot repro:
https://syzkaller.appspot.com/x/repro.syz?x=12c7a94f400000

Creates overlay mounts where the same directory is both in upper and lower
layers. Simplified example:

  mkdir foo work
  mount -t overlay none foo -o"lowerdir=.,upperdir=foo,workdir=work"

The repro runs several threads in parallel that attempt to chdir into foo
and attempt to symlink/rename/exec/mkdir the file bar.

The repro hits a WARN_ON() I placed in ovl_instantiate(), which suggests
that an overlay inode already exists in cache and is hashed by the pointer
of the real upper dentry that ovl_create_real() has just created. At the
point of the WARN_ON(), for overlay dir inode lock is held and upper dir
inode lock, so at first, I did not see how this was possible.

On a closer look, I see that after ovl_create_real(), because of the
overlapping upper and lower layers, a lookup by another thread can find the
file foo/bar that was just created in upper layer, at overlay path
foo/foo/bar and hash the an overlay inode with the new real dentry as lower
dentry. This is possible because the overlay directory foo/foo is not
locked and the upper dentry foo/bar is in dcache, so ovl_lookup() can find
it without taking upper dir inode shared lock.

Overlapping layers is considered a wrong setup which would result in
unexpected behavior, but it shouldn't crash the kernel and it shouldn't
trigger WARN_ON() either, so relax this WARN_ON() and leave a pr_warn()
instead to cover all cases of failure to get an overlay inode.

The error returned from failure to insert new inode to cache with
inode_insert5() was changed to -EEXIST, to distinguish from the error
-ENOMEM returned on failure to get/allocate inode with iget5_locked().

Reported-by: syzbot+9c69c282adc4edd2b540@syzkaller.appspotmail.com
Fixes: 01b39dcc9568 ("ovl: use inode_insert5() to hash a newly...")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-08 13:25:53 +02:00
Linus Torvalds
d27fb65bc2 Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc dcache updates from Al Viro:
 "Most of this pile is putting name length into struct name_snapshot and
  making use of it.

  The beginning of this series ("ovl_lookup_real_one(): don't bother
  with strlen()") ought to have been split in two (separate switch of
  name_snapshot to struct qstr from overlayfs reaping the trivial
  benefits of that), but I wanted to avoid a rebase - by the time I'd
  spotted that it was (a) in -next and (b) close to 5.1-final ;-/"

* 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  audit_compare_dname_path(): switch to const struct qstr *
  audit_update_watch(): switch to const struct qstr *
  inotify_handle_event(): don't bother with strlen()
  fsnotify: switch send_to_group() and ->handle_event to const struct qstr *
  fsnotify(): switch to passing const struct qstr * for file_name
  switch fsnotify_move() to passing const struct qstr * for old_name
  ovl_lookup_real_one(): don't bother with strlen()
  sysv: bury the broken "quietly truncate the long filenames" logics
  nsfs: unobfuscate
  unexport d_alloc_pseudo()
2019-05-07 20:03:32 -07:00
Jiufei Xue
98487de318 ovl: check the capability before cred overridden
We found that it return success when we set IMMUTABLE_FL flag to a file in
docker even though the docker didn't have the capability
CAP_LINUX_IMMUTABLE.

The commit d1d04ef8572b ("ovl: stack file ops") and dab5ca8fd9dd ("ovl: add
lsattr/chattr support") implemented chattr operations on a regular overlay
file. ovl_real_ioctl() overridden the current process's subjective
credentials with ofs->creator_cred which have the capability
CAP_LINUX_IMMUTABLE so that it will return success in
vfs_ioctl()->cap_capable().

Fix this by checking the capability before cred overridden. And here we
only care about APPEND_FL and IMMUTABLE_FL, so get these information from
inode.

[SzM: move check and call to underlying fs inside inode locked region to
prevent two such calls from racing with each other]

Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-06 14:00:37 +02:00
Amir Goldstein
d989903058 ovl: do not generate duplicate fsnotify events for "fake" path
Overlayfs "fake" path is used for stacked file operations on underlying
files.  Operations on files with "fake" path must not generate fsnotify
events with path data, because those events have already been generated at
overlayfs layer and because the reported event->fd for fanotify marks on
underlying inode/filesystem will have the wrong path (the overlayfs path).

Link: https://lore.kernel.org/linux-fsdevel/20190423065024.12695-1-jencce.kernel@gmail.com/
Reported-by: Murphy Zhou <jencce.kernel@gmail.com>
Fixes: d1d04ef8572b ("ovl: stack file ops")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-06 13:54:51 +02:00
Amir Goldstein
9e46b840c7 ovl: support stacked SEEK_HOLE/SEEK_DATA
Overlay file f_pos is the master copy that is preserved
through copy up and modified on read/write, but only real
fs knows how to SEEK_HOLE/SEEK_DATA and real fs may impose
limitations that are more strict than ->s_maxbytes for specific
files, so we use the real file to perform seeks.

We do not call real fs for SEEK_CUR:0 query and for SEEK_SET:0
requests.

Fixes: d1d04ef8572b ("ovl: stack file ops")
Reported-by: Eddie Horng <eddiehorng.tw@gmail.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-06 13:54:51 +02:00