We need to make some room in struct ovl_entry to store information
about redirected ancestors for NFS export, so cram two booleans as
bit flags.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
A directory index is a directory type entry in index dir with a
"trusted.overlay.upper" xattr containing an encoded ovl_fh of the merge
directory upper dir inode.
On lookup of non-dir files, lower file is followed by origin file handle.
On lookup of dir entries, lower dir is found by name and then compared
to origin file handle. We only trust dir index if we verified that lower
dir matches origin file handle, otherwise index may be inconsistent and
we ignore it.
If we find an indexed non-upper dir or an indexed merged dir, whose
index 'upper' xattr points to a different upper dir, that means that the
lower directory may be also referenced by another upper dir via redirect,
so we fail the lookup on inconsistency error.
To be consistent with directory index entries format, the association of
index dir to upper root dir, that was stored by older kernels in
"trusted.overlay.origin" xattr is now stored in "trusted.overlay.upper"
xattr. This also serves as an indication that overlay was mounted with a
kernel that support index directory entries. For backward compatibility,
if an 'origin' xattr exists on the index dir we also verify it on mount.
Directory index entries are going to be used for NFS export.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Introduce the "nfs_export" config, module and mount options.
The NFS export feature depends on the "index" feature and enables two
implicit overlayfs features: "index_all" and "verify_lower".
The "index_all" feature creates an index on copy up of every file and
directory. The "verify_lower" feature uses the full index to detect
overlay filesystems inconsistencies on lookup, like redirect from
multiple upper dirs to the same lower dir.
NFS export can be enabled for non-upper mount with no index. However,
because lower layer redirects cannot be verified with the index, enabling
NFS export support on an overlay with no upper layer requires turning off
redirect follow (e.g. "redirect_dir=nofollow").
The full index may incur some overhead on mount time, especially when
verifying that lower directory file handles are not stale.
NFS export support, full index and consistency verification will be
implemented by following patches.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Remove the "origin" language from the functions that handle set, get
and verify of "origin" xattr and pass the xattr name as an argument.
The same helpers are going to be used for NFS export to get, get and
verify the "upper" xattr for directory index entries.
ovl_verify_origin() is now a helper used only to verify non upper
file handle stored in "origin" xattr of upper inode.
The upper root dir file handle is still stored in "origin" xattr on
the index dir for backward compatibility. This is going to be changed
by the patch that adds directory index entries support.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Pass the fs instance with lower_layers array instead of the dentry
lowerstack array to ovl_check_origin_fh(), because the dentry members
of lowerstack play no role in this helper.
This change simplifies the argument list of ovl_check_origin(),
ovl_cleanup_index() and ovl_verify_index().
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Store the fs root layer index inside ovl_layer struct, so we can
get the root fs layer index from merge dir lower layer instead of
find it with ovl_find_layer() helper.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
When work dir creation fails, a warning is emitted and overlay is
mounted r/o. Trying to remount r/w will fail with no work dir.
When index dir creation fails, the same warning is emitted and overlay
is mounted r/o, but trying to remount r/w will succeed. This may cause
unintentional corruption of filesystem consistency.
Adjust the behavior of index dir creation failure to that of work dir
creation failure and do not allow to remount r/w. User needs to state
an explicitly intention to work without an index by mounting with
option 'index=off' to allow r/w mount with no index dir.
When mounting with option 'index=on' and no 'upperdir', index is
implicitly disabled, so do not warn about no file handle support.
The issue was introduced with inodes index feature in v4.13, but this
patch will not apply cleanly before ovl_fill_super() re-factoring in
v4.15.
Fixes: 02bcd15774 ("ovl: introduce the inodes index dir feature")
Cc: <stable@vger.kernel.org> #v4.13
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Overlayfs falls back to index=off if lower/upper fs does not support
file handles. Do the same if upper fs does not support xattr.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
There are several write operations on upper fs not covered by
mnt_want_write():
- test set/remove OPAQUE xattr
- test create O_TMPFILE
- set ORIGIN xattr in ovl_verify_origin()
- cleanup of index entries in ovl_indexdir_cleanup()
Some of these go way back, but this patch only applies over the
v4.14 re-factoring of ovl_fill_super().
Cc: <stable@vger.kernel.org> #v4.14
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fsnotify pins a watched directory inode in cache, but if directory dentry
is released, new lookup will allocate a new dentry and a new inode.
Directory events will be notified on the new inode, while fsnotify listener
is watching the old pinned inode.
Hash all directory inodes to reuse the pinned inode on lookup. Pure upper
dirs are hashes by real upper inode, merge and lower dirs are hashed by
real lower inode.
The reference to lower inode was being held by the lower dentry object
in the overlay dentry (oe->lowerstack[0]). Releasing the overlay dentry
may drop lower inode refcount to zero. Add a refcount on behalf of the
overlay inode to prevent that.
As a by-product, hashing directory inodes also detects multiple
redirected dirs to the same lower dir and uncovered redirected dir
target on and returns -ESTALE on lookup.
The reported issue dates back to initial version of overlayfs, but this
patch depends on ovl_inode code that was introduced in kernel v4.13.
Cc: <stable@vger.kernel.org> #v4.13
Reported-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Tested-by: Niklas Cassel <niklas.cassel@axis.com>
When executing filesystem sync or umount on overlayfs,
dirty data does not get synced as expected on upper filesystem.
This patch fixes sync filesystem method to keep data consistency
for overlayfs.
Signed-off-by: Chengguang Xu <cgxu@mykernel.net>
Fixes: e593b2bf51 ("ovl: properly implement sync_filesystem()")
Cc: <stable@vger.kernel.org> #4.11
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Overlayfs is following redirects even when redirects are disabled. If this
is unintentional (probably the majority of cases) then this can be a
problem. E.g. upper layer comes from untrusted USB drive, and attacker
crafts a redirect to enable read access to otherwise unreadable
directories.
If "redirect_dir=off", then turn off following as well as creation of
redirects. If "redirect_dir=follow", then turn on following, but turn off
creation of redirects (which is what "redirect_dir=off" does now).
This is a backward incompatible change, so make it dependent on a config
option.
Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This is a pure automated search-and-replace of the internal kernel
superblock flags.
The s_flags are now called SB_*, with the names and the values for the
moment mirroring the MS_* flags that they're equivalent to.
Note how the MS_xyz flags are the ones passed to the mount system call,
while the SB_xyz flags are what we then use in sb->s_flags.
The script to do this was:
# places to look in; re security/*: it generally should *not* be
# touched (that stuff parses mount(2) arguments directly), but
# there are two places where we really deal with superblock flags.
FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
include/linux/fs.h include/uapi/linux/bfs_fs.h \
security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
# the list of MS_... constants
SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
ACTIVE NOUSER"
SED_PROG=
for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done
# we want files that contain at least one of MS_...,
# with fs/namespace.c and fs/pnode.c excluded.
L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')
for f in $L; do sed -i $f $SED_PROG; done
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename all "struct ovl_fs" pointers to "ofs". The "ufs" name is historical
and can only be found in overlayfs/super.c.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Move calling ovl_get_lower_layers() into ovl_get_lowerstack().
ovl_get_lowerstack() now returns the root dentry's filled in ovl_entry.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Move calling ovl_get_workdir() into ovl_get_workpath().
Rename ovl_get_workdir() to ovl_make_workdir() and ovl_get_workpath() to
ovl_get_workdir().
Workpath is now not needed outside ovl_get_workdir().
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Merge ovl_get_upper() and ovl_get_upperpath().
The resulting function is named ovl_get_upper(), though it still returns
upperpath as well.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Remove "sb" and "dentry" arguments of ovl_workdir_create() and related
functions. Move setting MS_RDONLY flag to callers.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Move ovl_get_upper() immediately after ovl_get_upperpath(),
ovl_get_workdir() immediately after ovl_get_workdir() and
ovl_get_lower_layers() immediately after ovl_get_lowerstack().
Also move prepare_creds() up to where other allocations are happening.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Generate unique values of st_dev per lower layer for non-samefs
overlay mount. The unique values are obtained by allocating anonymous
bdevs for each of the lowerdirs in the overlayfs instance.
The anonymous bdev is going to be returned by stat(2) for lowerdir
non-dir entries in non-samefs case.
[amir: split from ovl_getattr() and re-structure patches]
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Define new structures to represent overlay instance lower layers and
overlay merge dir lower layers to make room for storing more per layer
information in-memory.
Instead of keeping the fs instance lower layers in an array of struct
vfsmount, keep them in an array of new struct ovl_layer, that has a
pointer to struct vfsmount.
Instead of keeping the dentry lower layers in an array of struct path,
keep them in an array of new struct ovl_path, that has a pointer to
struct dentry and to struct ovl_layer.
Add a small helper to find the fs layer id that correspopnds to a lower
struct ovl_path and use it in ovl_lookup().
[amir: split re-structure from anonymous bdev patch]
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Most overlayfs c files already explicitly include ovl_entry.h
to use overlay entry struct definitions and upcoming changes
are going to require even more c files to include this header.
All overlayfs c files include overlayfs.h and overlayfs.h itself
refers to some structs defined in ovl_entry.h, so it seems more
logic to include ovl_entry.h from overlayfs.h than from c files.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If a non-merge dir in an overlay mount has an overlay.origin xattr, it
means it was once an upper merge dir, which may contain whiteouts and
then the lower dir was removed under it.
Do not iterate real dir directly in this case to avoid exposing whiteouts.
[SzM] Set OVL_WHITEOUT for all merge directories as well.
[amir] A directory that was just copied up does not have the OVL_WHITEOUTS
flag. We need to set it to fix merge dir iteration.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This was detected by fault injection test
Signed-off-by: Hirofumi Nakagawa <nklabs@gmail.com>
Fixes: 13cf199d00 ("ovl: allocate an ovl_inode struct")
Cc: <stable@vger.kernel.org> # v4.13
Enforcing exclusive ownership on upper/work dirs caused a docker
regression: https://github.com/moby/moby/issues/34672.
Euan spotted the regression and pointed to the offending commit.
Vivek has brought the regression to my attention and provided this
reproducer:
Terminal 1:
mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none
merged/
Terminal 2:
unshare -m
Terminal 1:
umount merged
mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none
merged/
mount: /root/overlay-testing/merged: none already mounted or mount point
busy
To fix the regression, I replaced the error with an alarming warning.
With index feature enabled, mount does fail, but logs a suggestion to
override exclusive dir protection by disabling index.
Note that index=off mount does take the inuse locks, so a concurrent
index=off will issue the warning and a concurrent index=on mount will fail.
Documentation was updated to reflect this change.
Fixes: 2cac0c00a6 ("ovl: get exclusive ownership on upper/work dirs")
Cc: <stable@vger.kernel.org> # v4.13
Reported-by: Euan Kemp <euank@euank.com>
Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Pull mount flag updates from Al Viro:
"Another chunk of fmount preparations from dhowells; only trivial
conflicts for that part. It separates MS_... bits (very grotty
mount(2) ABI) from the struct super_block ->s_flags (kernel-internal,
only a small subset of MS_... stuff).
This does *not* convert the filesystems to new constants; only the
infrastructure is done here. The next step in that series is where the
conflicts would be; that's the conversion of filesystems. It's purely
mechanical and it's better done after the merge, so if you could run
something like
list=$(for i in MS_RDONLY MS_NOSUID MS_NODEV MS_NOEXEC MS_SYNCHRONOUS MS_MANDLOCK MS_DIRSYNC MS_NOATIME MS_NODIRATIME MS_SILENT MS_POSIXACL MS_KERNMOUNT MS_I_VERSION MS_LAZYTIME; do git grep -l $i fs drivers/staging/lustre drivers/mtd ipc mm include/linux; done|sort|uniq|grep -v '^fs/namespace.c$')
sed -i -e 's/\<MS_RDONLY\>/SB_RDONLY/g' \
-e 's/\<MS_NOSUID\>/SB_NOSUID/g' \
-e 's/\<MS_NODEV\>/SB_NODEV/g' \
-e 's/\<MS_NOEXEC\>/SB_NOEXEC/g' \
-e 's/\<MS_SYNCHRONOUS\>/SB_SYNCHRONOUS/g' \
-e 's/\<MS_MANDLOCK\>/SB_MANDLOCK/g' \
-e 's/\<MS_DIRSYNC\>/SB_DIRSYNC/g' \
-e 's/\<MS_NOATIME\>/SB_NOATIME/g' \
-e 's/\<MS_NODIRATIME\>/SB_NODIRATIME/g' \
-e 's/\<MS_SILENT\>/SB_SILENT/g' \
-e 's/\<MS_POSIXACL\>/SB_POSIXACL/g' \
-e 's/\<MS_KERNMOUNT\>/SB_KERNMOUNT/g' \
-e 's/\<MS_I_VERSION\>/SB_I_VERSION/g' \
-e 's/\<MS_LAZYTIME\>/SB_LAZYTIME/g' \
$list
and commit it with something along the lines of 'convert filesystems
away from use of MS_... constants' as commit message, it would save a
quite a bit of headache next cycle"
* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
VFS: Differentiate mount flags (MS_*) from internal superblock flags
VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)
vfs: Add sb_rdonly(sb) to query the MS_RDONLY flag on s_flags
Need to treat non-regular overlayfs files the same as regular files when
checking for an atime update.
Add a d_real() flag to make it return the upper dentry for all file types.
Reported-by: "zhangyi (F)" <yi.zhang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
d_real() is never called with a negative dentry. So remove the
d_is_negative() check (which would never trigger anyway, since d_is_reg()
returns false for a negative dentry).
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Impure directories are ones which contain objects with origins (i.e. those
that have been copied up). These are relevant to readdir operation only
because of the d_ino field, no other transformation is necessary. Also a
directory can become impure between two getdents(2) calls.
This patch creates a cache for impure directories. Unlike the cache for
merged directories, this one only contains entries with origin and is not
refcounted but has a its lifetime tied to that of the dentry.
Similarly to the merged cache, the impure cache is invalidated based on a
version number. This version number is incremented when an entry with
origin is added or removed from the directory.
If the cache is empty, then the impure xattr is removed from the directory.
This patch also fixes up handling of d_ino for the ".." entry if the parent
directory is merged.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
inode_doinit_with_dentry() in SELinux wants to read the upper inode's xattr
to get security label, and ovl_xattr_get() calls ovl_dentry_real(), which
depends on dentry->d_inode, but d_inode is null and not initialized yet at
this point resulting in an Oops.
Fix by getting the upperdentry info from the inode directly in this case.
Reported-by: Eryu Guan <eguan@redhat.com>
Fixes: 09d8b58673 ("ovl: move __upperdentry to ovl_inode")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Firstly by applying the following with coccinelle's spatch:
@@ expression SB; @@
-SB->s_flags & MS_RDONLY
+sb_rdonly(SB)
to effect the conversion to sb_rdonly(sb), then by applying:
@@ expression A, SB; @@
(
-(!sb_rdonly(SB)) && A
+!sb_rdonly(SB) && A
|
-A != (sb_rdonly(SB))
+A != sb_rdonly(SB)
|
-A == (sb_rdonly(SB))
+A == sb_rdonly(SB)
|
-!(sb_rdonly(SB))
+!sb_rdonly(SB)
|
-A && (sb_rdonly(SB))
+A && sb_rdonly(SB)
|
-A || (sb_rdonly(SB))
+A || sb_rdonly(SB)
|
-(sb_rdonly(SB)) != A
+sb_rdonly(SB) != A
|
-(sb_rdonly(SB)) == A
+sb_rdonly(SB) == A
|
-(sb_rdonly(SB)) && A
+sb_rdonly(SB) && A
|
-(sb_rdonly(SB)) || A
+sb_rdonly(SB) || A
)
@@ expression A, B, SB; @@
(
-(sb_rdonly(SB)) ? 1 : 0
+sb_rdonly(SB)
|
-(sb_rdonly(SB)) ? A : B
+sb_rdonly(SB) ? A : B
)
to remove left over excess bracketage and finally by applying:
@@ expression A, SB; @@
(
-(A & MS_RDONLY) != sb_rdonly(SB)
+(bool)(A & MS_RDONLY) != sb_rdonly(SB)
|
-(A & MS_RDONLY) == sb_rdonly(SB)
+(bool)(A & MS_RDONLY) == sb_rdonly(SB)
)
to make comparisons against the result of sb_rdonly() (which is a bool)
work correctly.
Signed-off-by: David Howells <dhowells@redhat.com>
ovl_workdir_create() returns a valid index dentry or NULL.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
On failure to prepare_creds(), mount fails with a random
return value, as err was last set to an integer cast of
a valid lower mnt pointer or set to 0 if inodes index feature
is enabled.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 3fe6e52f06 ("ovl: override creds with the ones from ...")
Cc: <stable@vger.kernel.org> # v4.7
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
index entry should live only as long as there are upper or lower
hardlinks.
Cleanup orphan index entries on mount and when dropping the last
overlay inode nlink.
When about to cleanup or link up to orphan index and the index inode
nlink > 1, admit that something went wrong and adjust overlay nlink
to index inode nlink - 1 to prevent it from dropping below zero.
This could happen when adding lower hardlinks underneath a mounted
overlay and then trying to unlink them.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
For rename, we need to ensure that an upper alias exists for hard links
before attempting the operation. Introduce a flag in ovl_entry to track
the state of the upper alias.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Bad index entries are entries whose name does not match the
origin file handle stored in trusted.overlay.origin xattr.
Bad index entries could be a result of a system power off in
the middle of copy up.
Stale index entries are entries whose origin file handle is
stale. Stale index entries could be a result of copying layers
or removing lower entries while the overlay is not mounted.
The case of copying layers should be detected earlier by the
verification of upper root dir origin and index dir origin.
Both bad and stale index entries are detected and removed
on mount.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
An index dir contains persistent hardlinks to files in upper dir.
Therefore, we must never mount an existing index dir with a differnt
upper dir.
Store the upper root dir file handle in index dir inode when index
dir is created and verify the file handle before using an existing
index dir on mount.
Add an 'is_upper' flag to the overlay file handle encoding and set it
when encoding the upper root file handle. This is not critical for index
dir verification, but it is good practice towards a standard overlayfs
file handle format for NFS export.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Amir Goldstein