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  1. 10 11月, 2018 1 次提交
    • V
      ext4: missing !bh check in ext4_xattr_inode_write() · eb6984fa
      由 Vasily Averin 提交于 
      According to Ted Ts'o ext4_getblk() called in ext4_xattr_inode_write()
should not return bh = NULL

The only time that bh could be NULL, then, would be in the case of
something really going wrong; a programming error elsewhere (perhaps a
wild pointer dereference) or I/O error causing on-disk file system
corruption (although that would be highly unlikely given that we had
*just* allocated the blocks and so the metadata blocks in question
probably would still be in the cache).

Fixes: e50e5129 ("ext4: xattr-in-inode support")
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 4.13
      eb6984fa
  3. 09 11月, 2018 3 次提交
  5. 08 11月, 2018 8 次提交
    • E
      mount: Prevent MNT_DETACH from disconnecting locked mounts · 9c8e0a1b
      由 Eric W. Biederman 提交于 
      Timothy Baldwin <timbaldwin@fastmail.co.uk> wrote:
> As per mount_namespaces(7) unprivileged users should not be able to look under mount points:
>
>   Mounts that come as a single unit from more privileged mount are locked
>   together and may not be separated in a less privileged mount namespace.
>
> However they can:
>
> 1. Create a mount namespace.
> 2. In the mount namespace open a file descriptor to the parent of a mount point.
> 3. Destroy the mount namespace.
> 4. Use the file descriptor to look under the mount point.
>
> I have reproduced this with Linux 4.16.18 and Linux 4.18-rc8.
>
> The setup:
>
> $ sudo sysctl kernel.unprivileged_userns_clone=1
> kernel.unprivileged_userns_clone = 1
> $ mkdir -p A/B/Secret
> $ sudo mount -t tmpfs hide A/B
>
>
> "Secret" is indeed hidden as expected:
>
> $ ls -lR A
> A:
> total 0
> drwxrwxrwt 2 root root 40 Feb 12 21:08 B
>
> A/B:
> total 0
>
>
> The attack revealing "Secret":
>
> $ unshare -Umr sh -c "exec unshare -m ls -lR /proc/self/fd/4/ 4<A"
> /proc/self/fd/4/:
> total 0
> drwxr-xr-x 3 root root 60 Feb 12 21:08 B
>
> /proc/self/fd/4/B:
> total 0
> drwxr-xr-x 2 root root 40 Feb 12 21:08 Secret
>
> /proc/self/fd/4/B/Secret:
> total 0

I tracked this down to put_mnt_ns running passing UMOUNT_SYNC and
disconnecting all of the mounts in a mount namespace.  Fix this by
factoring drop_mounts out of drop_collected_mounts and passing
0 instead of UMOUNT_SYNC.

There are two possible behavior differences that result from this.
- No longer setting UMOUNT_SYNC will no longer set MNT_SYNC_UMOUNT on
  the vfsmounts being unmounted.  This effects the lazy rcu walk by
  kicking the walk out of rcu mode and forcing it to be a non-lazy
  walk.
- No longer disconnecting locked mounts will keep some mounts around
  longer as they stay because the are locked to other mounts.

There are only two users of drop_collected mounts: audit_tree.c and
put_mnt_ns.

In audit_tree.c the mounts are private and there are no rcu lazy walks
only calls to iterate_mounts. So the changes should have no effect
except for a small timing effect as the connected mounts are disconnected.

In put_mnt_ns there may be references from process outside the mount
namespace to the mounts.  So the mounts remaining connected will
be the bug fix that is needed.  That rcu walks are allowed to continue
appears not to be a problem especially as the rcu walk change was about
an implementation detail not about semantics.

Cc: stable@vger.kernel.org
Fixes: 5ff9d8a6 ("vfs: Lock in place mounts from more privileged users")
Reported-by: NTimothy Baldwin <timbaldwin@fastmail.co.uk>
Tested-by: NTimothy Baldwin <timbaldwin@fastmail.co.uk>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
      9c8e0a1b
    • E
      mount: Don't allow copying MNT_UNBINDABLE|MNT_LOCKED mounts · df7342b2
      由 Eric W. Biederman 提交于 
      Jonathan Calmels from NVIDIA reported that he's able to bypass the
mount visibility security check in place in the Linux kernel by using
a combination of the unbindable property along with the private mount
propagation option to allow a unprivileged user to see a path which
was purposefully hidden by the root user.

Reproducer:
  # Hide a path to all users using a tmpfs
  root@castiana:~# mount -t tmpfs tmpfs /sys/devices/
  root@castiana:~#

  # As an unprivileged user, unshare user namespace and mount namespace
  stgraber@castiana:~$ unshare -U -m -r

  # Confirm the path is still not accessible
  root@castiana:~# ls /sys/devices/

  # Make /sys recursively unbindable and private
  root@castiana:~# mount --make-runbindable /sys
  root@castiana:~# mount --make-private /sys

  # Recursively bind-mount the rest of /sys over to /mnnt
  root@castiana:~# mount --rbind /sys/ /mnt

  # Access our hidden /sys/device as an unprivileged user
  root@castiana:~# ls /mnt/devices/
  breakpoint cpu cstate_core cstate_pkg i915 intel_pt isa kprobe
  LNXSYSTM:00 msr pci0000:00 platform pnp0 power software system
  tracepoint uncore_arb uncore_cbox_0 uncore_cbox_1 uprobe virtual

Solve this by teaching copy_tree to fail if a mount turns out to be
both unbindable and locked.

Cc: stable@vger.kernel.org
Fixes: 5ff9d8a6 ("vfs: Lock in place mounts from more privileged users")
Reported-by: NJonathan Calmels <jcalmels@nvidia.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
      df7342b2
    • E
      mount: Retest MNT_LOCKED in do_umount · 25d202ed
      由 Eric W. Biederman 提交于 
      It was recently pointed out that the one instance of testing MNT_LOCKED
outside of the namespace_sem is in ksys_umount.

Fix that by adding a test inside of do_umount with namespace_sem and
the mount_lock held.  As it helps to fail fails the existing test is
maintained with an additional comment pointing out that it may be racy
because the locks are not held.

Cc: stable@vger.kernel.org
Reported-by: NAl Viro <viro@ZenIV.linux.org.uk>
Fixes: 5ff9d8a6 ("vfs: Lock in place mounts from more privileged users")
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
      25d202ed
    • V
      ext4: fix buffer leak in __ext4_read_dirblock() on error path · de59fae0
      由 Vasily Averin 提交于 
      Fixes: dc6982ff ("ext4: refactor code to read directory blocks ...")
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 3.9
      de59fae0
    • V
      ext4: fix buffer leak in ext4_expand_extra_isize_ea() on error path · 53692ec0
      由 Vasily Averin 提交于 
      Fixes: de05ca85 ("ext4: move call to ext4_error() into ...")
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 4.17
      53692ec0
    • V
      ext4: fix buffer leak in ext4_xattr_move_to_block() on error path · 6bdc9977
      由 Vasily Averin 提交于 
      Fixes: 3f2571c1 ("ext4: factor out xattr moving")
Fixes: 6dd4ee7c ("ext4: Expand extra_inodes space per ...")
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 2.6.23
      6bdc9977
    • V
      ext4: release bs.bh before re-using in ext4_xattr_block_find() · 45ae932d
      由 Vasily Averin 提交于 
      bs.bh was taken in previous ext4_xattr_block_find() call,
it should be released before re-using

Fixes: 7e01c8e5 ("ext3/4: fix uninitialized bs in ...")
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 2.6.26
      45ae932d
    • V
      ext4: fix buffer leak in ext4_xattr_get_block() on error path · ecaaf408
      由 Vasily Averin 提交于 
      Fixes: dec214d0 ("ext4: xattr inode deduplication")
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 4.13
      ecaaf408
  7. 07 11月, 2018 8 次提交
  9. 06 11月, 2018 3 次提交
    • D
      xfs: fix overflow in xfs_attr3_leaf_verify · 837514f7
      由 Dave Chinner 提交于 
      generic/070 on 64k block size filesystems is failing with a verifier
corruption on writeback or an attribute leaf block:

[   94.973083] XFS (pmem0): Metadata corruption detected at xfs_attr3_leaf_verify+0x246/0x260, xfs_attr3_leaf block 0x811480
[   94.975623] XFS (pmem0): Unmount and run xfs_repair
[   94.976720] XFS (pmem0): First 128 bytes of corrupted metadata buffer:
[   94.978270] 000000004b2e7b45: 00 00 00 00 00 00 00 00 3b ee 00 00 00 00 00 00  ........;.......
[   94.980268] 000000006b1db90b: 00 00 00 00 00 81 14 80 00 00 00 00 00 00 00 00  ................
[   94.982251] 00000000433f2407: 22 7b 5c 82 2d 5c 47 4c bb 31 1c 37 fa a9 ce d6  "{\.-\GL.1.7....
[   94.984157] 0000000010dc7dfb: 00 00 00 00 00 81 04 8a 00 0a 18 e8 dd 94 01 00  ................
[   94.986215] 00000000d5a19229: 00 a0 dc f4 fe 98 01 68 f0 d8 07 e0 00 00 00 00  .......h........
[   94.988171] 00000000521df36c: 0c 2d 32 e2 fe 20 01 00 0c 2d 58 65 fe 0c 01 00  .-2.. ...-Xe....
[   94.990162] 000000008477ae06: 0c 2d 5b 66 fe 8c 01 00 0c 2d 71 35 fe 7c 01 00  .-[f.....-q5.|..
[   94.992139] 00000000a4a6bca6: 0c 2d 72 37 fc d4 01 00 0c 2d d8 b8 f0 90 01 00  .-r7.....-......
[   94.994789] XFS (pmem0): xfs_do_force_shutdown(0x8) called from line 1453 of file fs/xfs/xfs_buf.c. Return address = ffffffff815365f3

This is failing this check:

                end = ichdr.freemap[i].base + ichdr.freemap[i].size;
                if (end < ichdr.freemap[i].base)
>>>>>                   return __this_address;
                if (end > mp->m_attr_geo->blksize)
                        return __this_address;

And from the buffer output above, the freemap array is:

	freemap[0].base = 0x00a0
	freemap[0].size = 0xdcf4	end = 0xdd94
	freemap[1].base = 0xfe98
	freemap[1].size = 0x0168	end = 0x10000
	freemap[2].base = 0xf0d8
	freemap[2].size = 0x07e0	end = 0xf8b8

These all look valid - the block size is 0x10000 and so from the
last check in the above verifier fragment we know that the end
of freemap[1] is valid. The problem is that end is declared as:

	uint16_t	end;

And (uint16_t)0x10000 = 0. So we have a verifier bug here, not a
corruption. Fix the verifier to use uint32_t types for the check and
hence avoid the overflow.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=201577Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      837514f7
    • D
      xfs: print buffer offsets when dumping corrupt buffers · bdec055b
      由 Darrick J. Wong 提交于 
      Use DUMP_PREFIX_OFFSET when printing hex dumps of corrupt buffers
because modern Linux now prints a 32-bit hash of our 64-bit pointer when
using DUMP_PREFIX_ADDRESS:

00000000b4bb4297: 00 00 00 00 00 00 00 00 3b ee 00 00 00 00 00 00  ........;.......
00000005ec77e26: 00 00 00 00 02 d0 5a 00 00 00 00 00 00 00 00 00  ......Z.........
000000015938018: 21 98 e8 b4 fd de 4c 07 bc ea 3c e5 ae b4 7c 48  !.....L...<...|H

This is totally worthless for a sequential dump since we probably only
care about tracking the buffer offsets and afaik there's no way to
recover the actual pointer from the hashed value.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
      bdec055b
    • C
      xfs: Fix error code in 'xfs_ioc_getbmap()' · 132bf672
      由 Christophe JAILLET 提交于 
      In this function, once 'buf' has been allocated, we unconditionally
return 0.
However, 'error' is set to some error codes in several error handling
paths.
Before commit 232b5194 ("xfs: simplify the xfs_getbmap interface")
this was not an issue because all error paths were returning directly,
but now that some cleanup at the end may be needed, we must propagate the
error code.

Fixes: 232b5194 ("xfs: simplify the xfs_getbmap interface")
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
      132bf672
  11. 04 11月, 2018 12 次提交
  13. 03 11月, 2018 5 次提交