Instances either don't look at it at all (the majority of cases) or
only want it to find the superblock (which can be had as dentry->d_sb).
A few cases that want more are actually safe with dentry->d_inode -
the only precaution needed is the check that it hadn't been replaced with
NULL by rmdir() or by overwriting rename(), which case should be simply
treated as cache miss.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/hfsplus/bfind.c: In function 'hfs_find_1st_rec_by_cnid':
(1) include/uapi/linux/swab.h:60:2: warning: 'search_cnid' may be used uninitialized in this function [-Wmaybe-uninitialized]
(2) include/uapi/linux/swab.h:60:2: warning: 'cur_cnid' may be used uninitialized in this function [-Wmaybe-uninitialized]
[akpm@linux-foundation.org: make the workaround more explicit]
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.
A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.
Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.
Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives. Allowing simple, safe,
well understood work-arounds to known problematic software.
This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work. While writing this patch I saw a handful of such
cases. The most significant being autofs that lives in the module
autofs4.
This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.
After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module. The common pattern in the kernel is to call request_module()
without regards to the users permissions. In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted. In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The fsck_hfs (under MacOS X) complains about unzeroed unused b-tree nodes
after deletion of folders' tree under Linux.
SYMPTOMS:
Running Disk Utiltiy's "Verify Disk" on "test" gives the following:
Verifying volume “Test”
Checking file systemChecking Journaled HFS Plus volume.
Checking extents overflow file.
Checking catalog file.
Unused node is not erased (node = 3111)
Checking multi-linked files.
Checking catalog hierarchy.
Checking extended attributes file.
Checking volume bitmap.
Checking volume information.
The volume Test was found corrupt and needs to be repaired.
Error: This disk needs to be repaired. Click Repair Disk.
REPRODUCING PATH:
1. Prepare HFS+ (non-case sensitive) partition (for example, 5GB)
under MacOS X.
2. Copy linux kernel source tree (for example, 3.7-rc6 version) on
this partition under MacOS X.
3. Then switch to Linux and mount this prepared partition.
4. Execute `sudo rm -r` under prepared directory with linux kernel
source tree.
5. Unmount and boot back into OS X.
6. Open up Disk Utility and verify partition.
REPRODUCIBILITY: 100%
FIX:
It is added code of node clearing in hfs_bnode_put() method for the case
when node has flag HFS_BNODE_DELETED.
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Reported-by: Kyle Laracey <kalaracey@gmail.com>
Acked-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge the rest of Andrew's patches for -rc1:
"A bunch of fixes and misc missed-out-on things.
That'll do for -rc1. I still have a batch of IPC patches which still
have a possible bug report which I'm chasing down."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (25 commits)
keys: use keyring_alloc() to create module signing keyring
keys: fix unreachable code
sendfile: allows bypassing of notifier events
SGI-XP: handle non-fatal traps
fat: fix incorrect function comment
Documentation: ABI: remove testing/sysfs-devices-node
proc: fix inconsistent lock state
linux/kernel.h: fix DIV_ROUND_CLOSEST with unsigned divisors
memcg: don't register hotcpu notifier from ->css_alloc()
checkpatch: warn on uapi #includes that #include <uapi/...
revert "rtc: recycle id when unloading a rtc driver"
mm: clean up transparent hugepage sysfs error messages
hfsplus: add error message for the case of failure of sync fs in delayed_sync_fs() method
hfsplus: rework processing of hfs_btree_write() returned error
hfsplus: rework processing errors in hfsplus_free_extents()
hfsplus: avoid crash on failed block map free
kcmp: include linux/ptrace.h
drivers/rtc/rtc-imxdi.c: must include <linux/spinlock.h>
mm: cma: WARN if freed memory is still in use
exec: do not leave bprm->interp on stack
...
Add to hfs_btree_write() a return of -EIO on failure of b-tree node
searching. Also add logic ofor processing errors from hfs_btree_write()
in hfsplus_system_write_inode() with a message about b-tree writing
failure.
[akpm@linux-foundation.org: reduce scope of `err', print errno on error]
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull vfs update from Al Viro:
- big one - consolidation of descriptor-related logics; almost all of
that is moved to fs/file.c
(BTW, I'm seriously tempted to rename the result to fd.c. As it is,
we have a situation when file_table.c is about handling of struct
file and file.c is about handling of descriptor tables; the reasons
are historical - file_table.c used to be about a static array of
struct file we used to have way back).
A lot of stray ends got cleaned up and converted to saner primitives,
disgusting mess in android/binder.c is still disgusting, but at least
doesn't poke so much in descriptor table guts anymore. A bunch of
relatively minor races got fixed in process, plus an ext4 struct file
leak.
- related thing - fget_light() partially unuglified; see fdget() in
there (and yes, it generates the code as good as we used to have).
- also related - bits of Cyrill's procfs stuff that got entangled into
that work; _not_ all of it, just the initial move to fs/proc/fd.c and
switch of fdinfo to seq_file.
- Alex's fs/coredump.c spiltoff - the same story, had been easier to
take that commit than mess with conflicts. The rest is a separate
pile, this was just a mechanical code movement.
- a few misc patches all over the place. Not all for this cycle,
there'll be more (and quite a few currently sit in akpm's tree)."
Fix up trivial conflicts in the android binder driver, and some fairly
simple conflicts due to two different changes to the sock_alloc_file()
interface ("take descriptor handling from sock_alloc_file() to callers"
vs "net: Providing protocol type via system.sockprotoname xattr of
/proc/PID/fd entries" adding a dentry name to the socket)
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (72 commits)
MAX_LFS_FILESIZE should be a loff_t
compat: fs: Generic compat_sys_sendfile implementation
fs: push rcu_barrier() from deactivate_locked_super() to filesystems
btrfs: reada_extent doesn't need kref for refcount
coredump: move core dump functionality into its own file
coredump: prevent double-free on an error path in core dumper
usb/gadget: fix misannotations
fcntl: fix misannotations
ceph: don't abuse d_delete() on failure exits
hypfs: ->d_parent is never NULL or negative
vfs: delete surplus inode NULL check
switch simple cases of fget_light to fdget
new helpers: fdget()/fdput()
switch o2hb_region_dev_write() to fget_light()
proc_map_files_readdir(): don't bother with grabbing files
make get_file() return its argument
vhost_set_vring(): turn pollstart/pollstop into bool
switch prctl_set_mm_exe_file() to fget_light()
switch xfs_find_handle() to fget_light()
switch xfs_swapext() to fget_light()
...
There's no reason to call rcu_barrier() on every
deactivate_locked_super(). We only need to make sure that all delayed rcu
free inodes are flushed before we destroy related cache.
Removing rcu_barrier() from deactivate_locked_super() affects some fast
paths. E.g. on my machine exit_group() of a last process in IPC
namespace takes 0.07538s. rcu_barrier() takes 0.05188s of that time.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
