Commit Graph

36 Commits

Author SHA1 Message Date
Eric W. Biederman 7f78e03513 fs: Limit sys_mount to only request filesystem modules.
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>
2013-03-03 19:36:31 -08:00
David Howells 9249e17fe0 VFS: Pass mount flags to sget()
Pass mount flags to sget() so that it can use them in initialising a new
superblock before the set function is called.  They could also be passed to the
compare function.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-14 16:38:34 +04:00
Al Viro 03e897a1ed logfs: missing cleanup on register_filesystem() failure
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-20 21:29:48 -04:00
Al Viro 48fde701af switch open-coded instances of d_make_root() to new helper
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-20 21:29:35 -04:00
Al Viro 8de5277879 vfs: check i_nlink limits in vfs_{mkdir,rename_dir,link}
New field of struct super_block - ->s_max_links.  Maximal allowed
value of ->i_nlink or 0; in the latter case all checks still need
to be done in ->link/->mkdir/->rename instances.  Note that this
limit applies both to directoris and to non-directories.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-03-20 21:29:32 -04:00
Joern Engel 1bcceaff8c logfs: Free areas before calling generic_shutdown_super()
Or hit an assertion in map_invalidatepage() instead.

Signed-off-by: Joern Engel <joern@logfs.org>
2012-01-28 11:42:39 +05:30
Prasad Joshi ecfd890991 logfs: set superblock shutdown flag after generic sb shutdown
While unmounting the file system LogFS calls generic_shutdown_super.
The function does file system independent superblock shutdown.
However, it might result in call file system specific inode eviction.

LogFS marks FS shutting down by setting bit LOGFS_SB_FLAG_SHUTDOWN in
super->s_flags. Since, inode eviction might call truncate on inode,
following BUG is observed when file system is unmounted:

------------[ cut here ]------------
kernel BUG at /home/prasad/logfs/segment.c:362!
invalid opcode: 0000 [#1] PREEMPT SMP
CPU 3
Modules linked in: logfs binfmt_misc ppdev virtio_blk parport_pc lp
	parport psmouse floppy virtio_pci serio_raw virtio_ring virtio

Pid: 1933, comm: umount Not tainted 3.0.0+ #4 Bochs Bochs
RIP: 0010:[<ffffffffa008c841>]  [<ffffffffa008c841>]
		logfs_segment_write+0x211/0x230 [logfs]
RSP: 0018:ffff880062d7b9e8  EFLAGS: 00010202
RAX: 000000000000000e RBX: ffff88006eca9000 RCX: 0000000000000000
RDX: ffff88006fd87c40 RSI: ffffea00014ff468 RDI: ffff88007b68e000
RBP: ffff880062d7ba48 R08: 8000000020451430 R09: 0000000000000000
R10: dead000000100100 R11: 0000000000000000 R12: ffff88006fd87c40
R13: ffffea00014ff468 R14: ffff88005ad0a460 R15: 0000000000000000
FS:  00007f25d50ea760(0000) GS:ffff88007fd80000(0000)
	knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000d05e48 CR3: 0000000062c72000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process umount (pid: 1933, threadinfo ffff880062d7a000,
	task ffff880070b44500)
Stack:
ffff880062d7ba38 ffff88005ad0a508 0000000000001000 0000000000000000
8000000020451430 ffffea00014ff468 ffff880062d7ba48 ffff88005ad0a460
ffff880062d7bad8 ffffea00014ff468 ffff88006fd87c40 0000000000000000
Call Trace:
[<ffffffffa0088fee>] logfs_write_i0+0x12e/0x190 [logfs]
[<ffffffffa0089360>] __logfs_write_rec+0x140/0x220 [logfs]
[<ffffffffa0089312>] __logfs_write_rec+0xf2/0x220 [logfs]
[<ffffffffa00894a4>] logfs_write_rec+0x64/0xd0 [logfs]
[<ffffffffa0089616>] __logfs_write_buf+0x106/0x110 [logfs]
[<ffffffffa008a19e>] logfs_write_buf+0x4e/0x80 [logfs]
[<ffffffffa008a6b8>] __logfs_write_inode+0x98/0x110 [logfs]
[<ffffffffa008a7c4>] logfs_truncate+0x54/0x290 [logfs]
[<ffffffffa008abfc>] logfs_evict_inode+0xdc/0x190 [logfs]
[<ffffffff8115eef5>] evict+0x85/0x170
[<ffffffff8115f126>] iput+0xe6/0x1b0
[<ffffffff8115b4a8>] shrink_dcache_for_umount_subtree+0x218/0x280
[<ffffffff8115ce91>] shrink_dcache_for_umount+0x51/0x90
[<ffffffff8114796c>] generic_shutdown_super+0x2c/0x100
[<ffffffffa008cc47>] logfs_kill_sb+0x57/0xf0 [logfs]
[<ffffffff81147de5>] deactivate_locked_super+0x45/0x70
[<ffffffff811487ea>] deactivate_super+0x4a/0x70
[<ffffffff81163934>] mntput_no_expire+0xa4/0xf0
[<ffffffff8116469f>] sys_umount+0x6f/0x380
[<ffffffff814dd46b>] system_call_fastpath+0x16/0x1b
Code: 55 c8 49 8d b6 a8 00 00 00 45 89 f9 45 89 e8 4c 89 e1 4c 89 55
b8 c7 04 24 00 00 00 00 e8 68 fc ff ff 4c 8b 55 b8 e9 3c ff ff ff <0f>
0b 0f 0b c7 45 c0 00 00 00 00 e9 44 fe ff ff 66 66 66 66 66
RIP  [<ffffffffa008c841>] logfs_segment_write+0x211/0x230 [logfs]
RSP <ffff880062d7b9e8>
---[ end trace fe6b040cea952290 ]---

Therefore, move super->s_flags setting after the fs-indenpendent work
has been finished.

Reviewed-by: Joern Engel <joern@logfs.org>
Signed-off-by: Prasad Joshi <prasadjoshi.linux@gmail.com>
2012-01-28 11:37:47 +05:30
Linus Torvalds 32aaeffbd4 Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
  Revert "tracing: Include module.h in define_trace.h"
  irq: don't put module.h into irq.h for tracking irqgen modules.
  bluetooth: macroize two small inlines to avoid module.h
  ip_vs.h: fix implicit use of module_get/module_put from module.h
  nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
  include: replace linux/module.h with "struct module" wherever possible
  include: convert various register fcns to macros to avoid include chaining
  crypto.h: remove unused crypto_tfm_alg_modname() inline
  uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
  pm_runtime.h: explicitly requires notifier.h
  linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
  miscdevice.h: fix up implicit use of lists and types
  stop_machine.h: fix implicit use of smp.h for smp_processor_id
  of: fix implicit use of errno.h in include/linux/of.h
  of_platform.h: delete needless include <linux/module.h>
  acpi: remove module.h include from platform/aclinux.h
  miscdevice.h: delete unnecessary inclusion of module.h
  device_cgroup.h: delete needless include <linux/module.h>
  net: sch_generic remove redundant use of <linux/module.h>
  net: inet_timewait_sock doesnt need <linux/module.h>
  ...

Fix up trivial conflicts (other header files, and  removal of the ab3550 mfd driver) in
 - drivers/media/dvb/frontends/dibx000_common.c
 - drivers/media/video/{mt9m111.c,ov6650.c}
 - drivers/mfd/ab3550-core.c
 - include/linux/dmaengine.h
2011-11-06 19:44:47 -08:00
Akinobu Mita 798248206b lib/string.c: introduce memchr_inv()
memchr_inv() is mainly used to check whether the whole buffer is filled
with just a specified byte.

The function name and prototype are stolen from logfs and the
implementation is from SLUB.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Acked-by: Joern Engel <joern@logfs.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:47 -07:00
Paul Gortmaker 143cb494cb fs: add module.h to files that were implicitly using it
Some files were using the complete module.h infrastructure without
actually including the header at all.  Fix them up in advance so
once the implicit presence is removed, we won't get failures like this:

  CC [M]  fs/nfsd/nfssvc.o
fs/nfsd/nfssvc.c: In function 'nfsd_create_serv':
fs/nfsd/nfssvc.c:335: error: 'THIS_MODULE' undeclared (first use in this function)
fs/nfsd/nfssvc.c:335: error: (Each undeclared identifier is reported only once
fs/nfsd/nfssvc.c:335: error: for each function it appears in.)
fs/nfsd/nfssvc.c: In function 'nfsd':
fs/nfsd/nfssvc.c:555: error: implicit declaration of function 'module_put_and_exit'
make[3]: *** [fs/nfsd/nfssvc.o] Error 1

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:31 -04:00
Linus Torvalds cce2c56e76 logfs: initialize superblock entries earlier
In particular, s_freeing_list needs to be initialized early, since it is
used on some of the error paths when mounts fail.  The mapping inode,
for example, would be initialized and then free'd on an error path
before s_freeing_list was initialized, but the inode drop operation
needs the s_freeing_list to be set up.

Normally you'd never see this, because not only is logfs fairly rare,
but a successful mount will never have any issues.

Reported-by: werner <w.landgraf@ru.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-03 16:10:25 -07:00
Al Viro a1da9e8ab6 switch logfs to ->mount()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-29 04:16:51 -04:00
Al Viro e5a0726a95 logfs: fix a leak in get_sb
a) switch ->put_device() to logfs_super *
b) actually call it on early failures in logfs_get_sb_device()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-29 04:16:48 -04:00
Al Viro 7d945a3aa7 logfs get_sb, part 3
take logfs_get_sb_device() calls to logfs_get_sb() itself

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-29 04:16:46 -04:00
Al Viro 0d85c79962 logfs get_sb, part 2
take setting s_bdev/s_mtd/s_devops to callers of logfs_get_sb_device(),
don't bother passing them separately

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-29 04:16:43 -04:00
Al Viro 71a1c0125f logfs get_sb massage, part 1
move allocation of logfs_super to logfs_get_sb, pass it to
logfs_get_sb_...().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-29 04:16:41 -04:00
Al Viro 8e22c1a4e4 logfs: get rid of magical inodes
ordering problems at ->kill_sb() time are solved by doing iput()
of these suckers in ->put_super()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:48:26 -04:00
Linus Torvalds 7d32c0aca4 Merge git://git.kernel.org/pub/scm/linux/kernel/git/joern/logfs
* git://git.kernel.org/pub/scm/linux/kernel/git/joern/logfs:
  logfs: handle powerfail on NAND flash
  logfs: handle errors from get_mtd_device()
  logfs: remove unused variable
  logfs: fix sync
  logfs: fix compile failure
  logfs: initialize li->li_refcount
  logfs: commit reservations under space pressure
  logfs: survive logfs_buf_recover read errors
  logfs: Close i_ino reuse race
  logfs: fix logfs_seek_hole()
  logfs: Return -EINVAL if filesystem image doesn't match
  LogFS: Fix typo in b6349ac8
  logfs: testing the wrong variable
2010-05-17 13:53:35 -07:00
Al Viro 265624495f Fix double-free in logfs
iput() is needed *until* we'd done successful d_alloc_root()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-15 07:16:33 -04:00
Joern Engel bba0b5c2c2 logfs: fix compile failure
When CONFIG_BLOCK is not enabled:

fs/logfs/super.c:142: error: implicit declaration of function 'bdev_get_queue'
fs/logfs/super.c:142: error: invalid type argument of '->' (have 'int')

Found by Randy Dunlap <randy.dunlap@oracle.com>

Signed-off-by: Joern Engel <joern@logfs.org>
2010-05-05 22:32:52 +02:00
Joern Engel ad342631f1 logfs: Return -EINVAL if filesystem image doesn't match
Signed-off-by: Joern Engel <joern@logfs.org>
2010-05-01 18:02:20 +02:00
Dan Carpenter 3272c8a57b logfs: testing the wrong variable
There is a typo here.  We should test "last" instead of "first".

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Joern Engel <joern@logfs.org>
2010-04-29 15:19:27 +02:00
Linus Torvalds 255f41c595 Merge git://git.kernel.org/pub/scm/linux/kernel/git/joern/logfs
* git://git.kernel.org/pub/scm/linux/kernel/git/joern/logfs:
  [LogFS] Split large truncated into smaller chunks
  [LogFS] Set s_bdi
  [LogFS] Prevent mempool_destroy NULL pointer dereference
  [LogFS] Move assertion
  [LogFS] Plug 8 byte information leak
  [LogFS] Prevent memory corruption on large deletes
  [LogFS] Remove unused method

Fix trivial conflict with added header includes in fs/logfs/super.c
2010-04-21 12:31:12 -07:00
Joern Engel b8639077ab [LogFS] Set s_bdi
Since 32a88aa1 sync() was turned into a NOP for logfs.  Worse, sync()
would not return an error, giving the illusion that writeout had
actually happened.

Afaics jffs2 was broken as well.

Signed-off-by: Joern Engel <joern@logfs.org>
2010-04-17 19:54:27 +02:00
Joern Engel 1f1b0008e8 [LogFS] Prevent mempool_destroy NULL pointer dereference
It would probably be better to just accept NULL pointers in
mempool_destroy().  But for the current -rc series let's keep things
simple.

This patch was lost in the cracks for a while.
Kevin Cernekee <cernekee@gmail.com> had to rediscover the problem and
send a similar patch because of it. :(

Signed-off-by: Joern Engel <joern@logfs.org>
2010-04-15 08:03:57 +02:00
Joern Engel 032d8f7268 [LogFS] Prevent memory corruption on large deletes
Removing sufficiently large files would create aliases for a large
number of segments.  This in turn results in a large number of journal
entries and an overflow of s_je_array.

Cheap fix is to add a BUG_ON, turning memory corruption into something
annoying, but less dangerous.  Real fix is to count the number of
affected segments and prevent the problem completely.

Signed-off-by: Joern Engel <joern@logfs.org>
2010-04-13 17:46:37 +02:00
Tejun Heo 336f5899d2 Merge branch 'master' into export-slabh 2010-04-05 11:37:28 +09:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Joern Engel 6f2e9e6a95 Use deactivate_locked_super
Found by Al Viro.

Signed-off-by: Joern Engel <joern@logfs.org>
2010-03-27 11:19:16 +01:00
Joern Engel 7db8064c17 Fix logfs_get_sb_final error path
rootdir was already allocated, so we must iput it again.
Found by Al Viro.

Signed-off-by: Joern Engel <joern@logfs.org>
2010-03-27 11:19:16 +01:00
Joern Engel faaa27ab91 Write out both superblocks on mismatch
If the first superblock is wrong and the second gets written, there
will still be a mismatch on next mount.  Write both to make sure they
match.

Signed-off-by: Joern Engel <joern@logfs.org>
2010-03-27 11:19:15 +01:00
Joern Engel 49137f2efb Open segment file before using it
logfs_recover_sb() needs it open.

Signed-off-by: Joern Engel <joern@logfs.org>
2010-03-27 11:19:13 +01:00
Joern Engel 6a08ab846c [LogFS] Check feature flags 2010-03-05 16:07:04 +01:00
Joern Engel c6d3830140 [LogFS] Only write journal if dirty
This prevents unnecessary journal writes.  More importantly it prevents
an oops due to a journal write on failed mount.
2010-03-04 21:36:19 +01:00
Joern Engel 9421502b4f [LogFS] Fix bdev erases
Erases for block devices were always just emulated by writing 0xff.
Some time back the write was removed and only the page cache was
changed to 0xff.  Superficialy a good idea with two problems:
1. Touching the page cache isn't necessary either.
2. However, writing out 0xff _is_ necessary for the journal.  As the
   journal is scanned linearly, an old non-overwritten commit entry
   can be used on next mount and cause havoc.

This should fix both aspects.
2010-03-04 21:30:58 +01:00
Joern Engel 5db53f3e80 [LogFS] add new flash file system
This is a new flash file system. See
Documentation/filesystems/logfs.txt

Signed-off-by: Joern Engel <joern@logfs.org>
2009-11-20 20:13:39 +01:00