Many file systems that implement the show_options hook fail to correctly
escape their output which could lead to unescaped characters (e.g. new
lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files. This
could lead to confusion, spoofed entries (resulting in things like
systemd issuing false d-bus "mount" notifications), and who knows what
else. This looks like it would only be the root user stepping on
themselves, but it's possible weird things could happen in containers or
in other situations with delegated mount privileges.
Here's an example using overlay with setuid fusermount trusting the
contents of /proc/mounts (via the /etc/mtab symlink). Imagine the use
of "sudo" is something more sneaky:
$ BASE="ovl"
$ MNT="$BASE/mnt"
$ LOW="$BASE/lower"
$ UP="$BASE/upper"
$ WORK="$BASE/work/ 0 0
none /proc fuse.pwn user_id=1000"
$ mkdir -p "$LOW" "$UP" "$WORK"
$ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt
$ cat /proc/mounts
none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0
none /proc fuse.pwn user_id=1000 0 0
$ fusermount -u /proc
$ cat /proc/mounts
cat: /proc/mounts: No such file or directory
This fixes the problem by adding new seq_show_option and
seq_show_option_n helpers, and updating the vulnerable show_option
handlers to use them as needed. Some, like SELinux, need to be open
coded due to unusual existing escape mechanisms.
[akpm@linux-foundation.org: add lost chunk, per Kees]
[keescook@chromium.org: seq_show_option should be using const parameters]
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Jan Kara <jack@suse.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: J. R. Okajima <hooanon05g@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
commit e548e9b93d makes the kclient
only re-send cap flush once during MDS failover. If the kclient sends
a cap flush after MDS enters reconnect stage but before MDS recovers.
The kclient will skip re-sending the same cap flush when MDS recovers.
This causes problem for newly created inode. The MDS handles cap
flushes before replaying unsafe requests, so it's possible that MDS
find corresponding inode is missing when handling cap flush. The fix
is reverting to old behaviour: always re-send when MDS recovers
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Pull more vfs updates from Al Viro:
"Assorted VFS fixes and related cleanups (IMO the most interesting in
that part are f_path-related things and Eric's descriptor-related
stuff). UFS regression fixes (it got broken last cycle). 9P fixes.
fs-cache series, DAX patches, Jan's file_remove_suid() work"
[ I'd say this is much more than "fixes and related cleanups". The
file_table locking rule change by Eric Dumazet is a rather big and
fundamental update even if the patch isn't huge. - Linus ]
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits)
9p: cope with bogus responses from server in p9_client_{read,write}
p9_client_write(): avoid double p9_free_req()
9p: forgetting to cancel request on interrupted zero-copy RPC
dax: bdev_direct_access() may sleep
block: Add support for DAX reads/writes to block devices
dax: Use copy_from_iter_nocache
dax: Add block size note to documentation
fs/file.c: __fget() and dup2() atomicity rules
fs/file.c: don't acquire files->file_lock in fd_install()
fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation
vfs: avoid creation of inode number 0 in get_next_ino
namei: make set_root_rcu() return void
make simple_positive() public
ufs: use dir_pages instead of ufs_dir_pages()
pagemap.h: move dir_pages() over there
remove the pointless include of lglock.h
fs: cleanup slight list_entry abuse
xfs: Correctly lock inode when removing suid and file capabilities
fs: Call security_ops->inode_killpriv on truncate
fs: Provide function telling whether file_remove_privs() will do anything
...
Pull Ceph updates from Sage Weil:
"We have a pile of bug fixes from Ilya, including a few patches that
sync up the CRUSH code with the latest from userspace.
There is also a long series from Zheng that fixes various issues with
snapshots, inline data, and directory fsync, some simplification and
improvement in the cap release code, and a rework of the caching of
directory contents.
To top it off there are a few small fixes and cleanups from Benoit and
Hong"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (40 commits)
rbd: use GFP_NOIO in rbd_obj_request_create()
crush: fix a bug in tree bucket decode
libceph: Fix ceph_tcp_sendpage()'s more boolean usage
libceph: Remove spurious kunmap() of the zero page
rbd: queue_depth map option
rbd: store rbd_options in rbd_device
rbd: terminate rbd_opts_tokens with Opt_err
ceph: fix ceph_writepages_start()
rbd: bump queue_max_segments
ceph: rework dcache readdir
crush: sync up with userspace
crush: fix crash from invalid 'take' argument
ceph: switch some GFP_NOFS memory allocation to GFP_KERNEL
ceph: pre-allocate data structure that tracks caps flushing
ceph: re-send flushing caps (which are revoked) in reconnect stage
ceph: send TID of the oldest pending caps flush to MDS
ceph: track pending caps flushing globally
ceph: track pending caps flushing accurately
libceph: fix wrong name "Ceph filesystem for Linux"
ceph: fix directory fsync
...
Before a page get locked, someone else can write data to the page
and increase the i_size. So we should re-check the i_size after
pages are locked.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Previously our dcache readdir code relies on that child dentries in
directory dentry's d_subdir list are sorted by dentry's offset in
descending order. When adding dentries to the dcache, if a dentry
already exists, our readdir code moves it to head of directory
dentry's d_subdir list. This design relies on dcache internals.
Al Viro suggests using ncpfs's approach: keeping array of pointers
to dentries in page cache of directory inode. the validity of those
pointers are presented by directory inode's complete and ordered
flags. When a dentry gets pruned, we clear directory inode's complete
flag in the d_prune() callback. Before moving a dentry to other
directory, we clear the ordered flag for both old and new directory.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
GFP_NOFS memory allocation is required for page writeback path.
But there is no need to use GFP_NOFS in syscall path and readpage
path
Signed-off-by: Yan, Zheng <zyan@redhat.com>
if flushing caps were revoked, we should re-send the cap flush in
client reconnect stage. This guarantees that MDS processes the cap
flush message before issuing the flushing caps to other client.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
According to this information, MDS can trim its completed caps flush
list (which is used to detect duplicated cap flush).
Signed-off-by: Yan, Zheng <zyan@redhat.com>
So we know TID of the oldest pending caps flushing. Later patch will
send this information to MDS, so that MDS can trim its completed caps
flush list.
Tracking pending caps flushing globally also simplifies syncfs code.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Previously we do not trace accurate TID for flushing caps. when
MDS failovers, we have no choice but to re-send all flushing caps
with a new TID. This can cause problem because MDS can has already
flushed some caps and has issued the same caps to other client.
The re-sent cap flush has a new TID, which makes MDS unable to
detect if it has already processed the cap flush.
This patch adds code to track pending caps flushing accurately.
When re-sending cap flush is needed, we use its original flush
TID.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
fsync() on directory should flush dirty caps and wait for any
uncommitted directory opertions to commit. But ceph_dir_fsync()
only waits for uncommitted directory opertions.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Current ceph_fsync() only flushes dirty caps and wait for them to be
flushed. It doesn't wait for caps that has already been flushing.
This patch makes ceph_fsync() wait for pending flushing caps too.
Besides, this patch also makes caps_are_flushed() peroperly handle
tid wrapping.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
when copying files to cephfs, file data may stay in page cache after
corresponding file is closed. Cached data use Fc capability. If we
include Fc capability in cap_wanted, MDS will treat files with cached
data as open files, and journal them in an EOpen event when trimming
log segment.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
No need to bifurcate wait now that we've got ceph_timeout_jiffies().
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
There are currently three libceph-level timeouts that the user can
specify on mount: mount_timeout, osd_idle_ttl and osdkeepalive. All of
these are in seconds and no checking is done on user input: negative
values are accepted, we multiply them all by HZ which may or may not
overflow, arbitrarily large jiffies then get added together, etc.
There is also a bug in the way mount_timeout=0 is handled. It's
supposed to mean "infinite timeout", but that's not how wait.h APIs
treat it and so __ceph_open_session() for example will busy loop
without much chance of being interrupted if none of ceph-mons are
there.
Fix all this by verifying user input, storing timeouts capped by
msecs_to_jiffies() in jiffies and using the new ceph_timeout_jiffies()
helper for all user-specified waits to handle infinite timeouts
correctly.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Previously we pre-allocate cap release messages for each caps. This
wastes lots of memory when there are large amount of caps. This patch
make the code not pre-allocate the cap release messages. Instead,
we add the corresponding ceph_cap struct to a list when releasing a
cap. Later when flush cap releases is needed, we allocate the cap
release messages dynamically.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
When ceph inode's i_head_snapc is NULL, __ceph_mark_dirty_caps()
accesses snap realm's cached_context. So we need take read lock
of snap_rwsem.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
when a snap notification contains no new snapshot, we can avoid
sending FLUSHSNAP message to MDS. But we still need to create
cap_snap in some case because it's required by write path and
page writeback path
Signed-off-by: Yan, Zheng <zyan@redhat.com>
In most cases that snap context is needed, we are holding
reference of CEPH_CAP_FILE_WR. So we can set ceph inode's
i_head_snapc when getting the CEPH_CAP_FILE_WR reference,
and make codes get snap context from i_head_snapc. This makes
the code simpler.
Another benefit of this change is that we can handle snap
notification more elegantly. Especially when snap context
is updated while someone else is doing write. The old queue
cap_snap code may set cap_snap's context to ether the old
context or the new snap context, depending on if i_head_snapc
is set. The new queue capp_snap code always set cap_snap's
context to the old snap context.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Cached_context in ceph_snap_realm is directly accessed by
uninline_data() and get_pool_perm(). This is racy in theory.
both uninline_data() and get_pool_perm() do not modify existing
object, they only create new object. So we can pass the empty
snap context to them. Unlike cached_context in ceph_snap_realm,
we do not need to protect the empty snap context.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
file_remove_suid() is a misnomer since it removes also file capabilities
stored in xattrs and sets S_NOSEC flag. Also should_remove_suid() tells
something else than whether file_remove_suid() call is necessary which
leads to bugs.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull fourth vfs update from Al Viro:
"d_inode() annotations from David Howells (sat in for-next since before
the beginning of merge window) + four assorted fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
RCU pathwalk breakage when running into a symlink overmounting something
fix I_DIO_WAKEUP definition
direct-io: only inc/dec inode->i_dio_count for file systems
fs/9p: fix readdir()
VFS: assorted d_backing_inode() annotations
VFS: fs/inode.c helpers: d_inode() annotations
VFS: fs/cachefiles: d_backing_inode() annotations
VFS: fs library helpers: d_inode() annotations
VFS: assorted weird filesystems: d_inode() annotations
VFS: normal filesystems (and lustre): d_inode() annotations
VFS: security/: d_inode() annotations
VFS: security/: d_backing_inode() annotations
VFS: net/: d_inode() annotations
VFS: net/unix: d_backing_inode() annotations
VFS: kernel/: d_inode() annotations
VFS: audit: d_backing_inode() annotations
VFS: Fix up some ->d_inode accesses in the chelsio driver
VFS: Cachefiles should perform fs modifications on the top layer only
VFS: AF_UNIX sockets should call mknod on the top layer only
Pull Ceph updates from Sage Weil:
"This time around we have a collection of CephFS fixes from Zheng
around MDS failure handling and snapshots, support for a new CRUSH
straw2 algorithm (to sync up with userspace) and several RBD cleanups
and fixes from Ilya, an error path leak fix from Taesoo, and then an
assorted collection of cleanups from others"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (28 commits)
rbd: rbd_wq comment is obsolete
libceph: announce support for straw2 buckets
crush: straw2 bucket type with an efficient 64-bit crush_ln()
crush: ensuring at most num-rep osds are selected
crush: drop unnecessary include from mapper.c
ceph: fix uninline data function
ceph: rename snapshot support
ceph: fix null pointer dereference in send_mds_reconnect()
ceph: hold on to exclusive caps on complete directories
libceph: simplify our debugfs attr macro
ceph: show non-default options only
libceph: expose client options through debugfs
libceph, ceph: split ceph_show_options()
rbd: mark block queue as non-rotational
libceph: don't overwrite specific con error msgs
ceph: cleanup unsafe requests when reconnecting is denied
ceph: don't zero i_wrbuffer_ref when reconnecting is denied
ceph: don't mark dirty caps when there is no auth cap
ceph: keep i_snap_realm while there are writers
libceph: osdmap.h: Add missing format newlines
...
If a directory is complete, we want to keep the exclusive
cap. So that MDS does not end up revoking the shared cap
on every create/unlink operation.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Don't pollute /proc/mounts with default options (presently these are
dcache, nofsc and acl). Leave the acl/noacl however - it's a bit of
a special case due to CONFIG_CEPH_FS_POSIX_ACL.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Split ceph_show_options() into two pieces and move the piece
responsible for printing client (libceph) options into net/ceph. This
way people adding a libceph option wouldn't have to remember to update
code in fs/ceph.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
remove_session_caps_cb() does not truncate dirty data in page
cache, but zeros i_wrbuffer_ref/i_wrbuffer_ref_head. This will
result negtive i_wrbuffer_ref/i_wrbuffer_ref_head
Signed-off-by: Yan, Zheng <zyan@redhat.com>
when reconnecting to MDS is denied, we remove session caps
forcibly. But it's possible there are ongoing write, the
write code needs to reference i_snap_realm. So if there are
ongoing write, we keep i_snap_realm.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Currently, there is no check for the kstrdup() for r_path2,
r_path1 and snapdir_name as various locations as there is a
possibility of failure during memory pressure. Therefore,
returning ENOMEM where the checks have been missed.
Signed-off-by: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Signed-off-by: Yan, Zheng <zyan@redhat.com>
When ceph_update_writeable_page fails (including -EAGAIN), it
unlocks (w/ unlock_page) the page but does not 'release'
(w/ page_cache_release) properly.
Upon error, properly set *pagep to NULL, indicating an error.
Signed-off-by: Taesoo Kim <tsgatesv@gmail.com>
Signed-off-by: Yan, Zheng <zyan@redhat.com>
return type of wait_for_completion_timeout is unsigned long not int. An
appropriately named unsigned long is added and the assignment fixed up.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Yan, Zheng <zyan@redhat.com>
This is only an API consolidation and should make things more readable
it replaces var * HZ / 1000 by msecs_to_jiffies(var).
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Yan, Zheng <zyan@redhat.com>
