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  1. 16 Nov, 2015 11 commits
  3. 30 Oct, 2015 23 commits
  5. 28 Oct, 2015 6 commits
    • Filipe Manana's avatar
      Btrfs: update fix for read corruption of compressed and shared extents · 5e7dd6c7
      Filipe Manana authored 
      commit 808f80b4 upstream.

My previous fix in commit 005efedf ("Btrfs: fix read corruption of
compressed and shared extents") was effective only if the compressed
extents cover a file range with a length that is not a multiple of 16
pages. That's because the detection of when we reached a different range
of the file that shares the same compressed extent as the previously
processed range was done at extent_io.c:__do_contiguous_readpages(),
which covers subranges with a length up to 16 pages, because
extent_readpages() groups the pages in clusters no larger than 16 pages.
So fix this by tracking the start of the previously processed file
range's extent map at extent_readpages().

The following test case for fstests reproduces the issue:

  seq=`basename $0`
  seqres=$RESULT_DIR/$seq
  echo "QA output created by $seq"
  tmp=/tmp/$$
  status=1	# failure is the default!
  trap "_cleanup; exit \$status" 0 1 2 3 15

  _cleanup()
  {
      rm -f $tmp.*
  }

  # get standard environment, filters and checks
  . ./common/rc
  . ./common/filter

  # real QA test starts here
  _need_to_be_root
  _supported_fs btrfs
  _supported_os Linux
  _require_scratch
  _require_cloner

  rm -f $seqres.full

  test_clone_and_read_compressed_extent()
  {
      local mount_opts=$1

      _scratch_mkfs >>$seqres.full 2>&1
      _scratch_mount $mount_opts

      # Create our test file with a single extent of 64Kb that is going to
      # be compressed no matter which compression algo is used (zlib/lzo).
      $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 64K" \
          $SCRATCH_MNT/foo | _filter_xfs_io

      # Now clone the compressed extent into an adjacent file offset.
      $CLONER_PROG -s 0 -d $((64 * 1024)) -l $((64 * 1024)) \
          $SCRATCH_MNT/foo $SCRATCH_MNT/foo

      echo "File digest before unmount:"
      md5sum $SCRATCH_MNT/foo | _filter_scratch

      # Remount the fs or clear the page cache to trigger the bug in
      # btrfs. Because the extent has an uncompressed length that is a
      # multiple of 16 pages, all the pages belonging to the second range
      # of the file (64K to 128K), which points to the same extent as the
      # first range (0K to 64K), had their contents full of zeroes instead
      # of the byte 0xaa. This was a bug exclusively in the read path of
      # compressed extents, the correct data was stored on disk, btrfs
      # just failed to fill in the pages correctly.
      _scratch_remount

      echo "File digest after remount:"
      # Must match the digest we got before.
      md5sum $SCRATCH_MNT/foo | _filter_scratch
  }

  echo -e "\nTesting with zlib compression..."
  test_clone_and_read_compressed_extent "-o compress=zlib"

  _scratch_unmount

  echo -e "\nTesting with lzo compression..."
  test_clone_and_read_compressed_extent "-o compress=lzo"

  status=0
  exit
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Tested-by: default avatarTimofey Titovets <nefelim4ag@gmail.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      5e7dd6c7
    • David Howells's avatar
      KEYS: Don't permit request_key() to construct a new keyring · ca564ff2
      David Howells authored 
      commit 911b79cd upstream.

If request_key() is used to find a keyring, only do the search part - don't
do the construction part if the keyring was not found by the search.  We
don't really want keyrings in the negative instantiated state since the
rejected/negative instantiation error value in the payload is unioned with
keyring metadata.

Now the kernel gives an error:

	request_key("keyring", "#selinux,bdekeyring", "keyring", KEY_SPEC_USER_SESSION_KEYRING) = -1 EPERM (Operation not permitted)
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Cc: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      ca564ff2
    • David Howells's avatar
      KEYS: Fix crash when attempt to garbage collect an uninstantiated keyring · 4944cea7
      David Howells authored 
      commit f05819df upstream.

The following sequence of commands:

    i=`keyctl add user a a @s`
    keyctl request2 keyring foo bar @t
    keyctl unlink $i @s

tries to invoke an upcall to instantiate a keyring if one doesn't already
exist by that name within the user's keyring set.  However, if the upcall
fails, the code sets keyring->type_data.reject_error to -ENOKEY or some
other error code.  When the key is garbage collected, the key destroy
function is called unconditionally and keyring_destroy() uses list_empty()
on keyring->type_data.link - which is in a union with reject_error.
Subsequently, the kernel tries to unlink the keyring from the keyring names
list - which oopses like this:

	BUG: unable to handle kernel paging request at 00000000ffffff8a
	IP: [<ffffffff8126e051>] keyring_destroy+0x3d/0x88
	...
	Workqueue: events key_garbage_collector
	...
	RIP: 0010:[<ffffffff8126e051>] keyring_destroy+0x3d/0x88
	RSP: 0018:ffff88003e2f3d30  EFLAGS: 00010203
	RAX: 00000000ffffff82 RBX: ffff88003bf1a900 RCX: 0000000000000000
	RDX: 0000000000000000 RSI: 000000003bfc6901 RDI: ffffffff81a73a40
	RBP: ffff88003e2f3d38 R08: 0000000000000152 R09: 0000000000000000
	R10: ffff88003e2f3c18 R11: 000000000000865b R12: ffff88003bf1a900
	R13: 0000000000000000 R14: ffff88003bf1a908 R15: ffff88003e2f4000
	...
	CR2: 00000000ffffff8a CR3: 000000003e3ec000 CR4: 00000000000006f0
	...
	Call Trace:
	 [<ffffffff8126c756>] key_gc_unused_keys.constprop.1+0x5d/0x10f
	 [<ffffffff8126ca71>] key_garbage_collector+0x1fa/0x351
	 [<ffffffff8105ec9b>] process_one_work+0x28e/0x547
	 [<ffffffff8105fd17>] worker_thread+0x26e/0x361
	 [<ffffffff8105faa9>] ? rescuer_thread+0x2a8/0x2a8
	 [<ffffffff810648ad>] kthread+0xf3/0xfb
	 [<ffffffff810647ba>] ? kthread_create_on_node+0x1c2/0x1c2
	 [<ffffffff815f2ccf>] ret_from_fork+0x3f/0x70
	 [<ffffffff810647ba>] ? kthread_create_on_node+0x1c2/0x1c2

Note the value in RAX.  This is a 32-bit representation of -ENOKEY.

The solution is to only call ->destroy() if the key was successfully
instantiated.
Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarDmitry Vyukov <dvyukov@google.com>
Cc: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      4944cea7
    • David Howells's avatar
      KEYS: Fix race between key destruction and finding a keyring by name · 35694b04
      David Howells authored 
      commit 94c4554b upstream.

There appears to be a race between:

 (1) key_gc_unused_keys() which frees key->security and then calls
     keyring_destroy() to unlink the name from the name list

 (2) find_keyring_by_name() which calls key_permission(), thus accessing
     key->security, on a key before checking to see whether the key usage is 0
     (ie. the key is dead and might be cleaned up).

Fix this by calling ->destroy() before cleaning up the core key data -
including key->security.
Reported-by: default avatarPetr Matousek <pmatouse@redhat.com>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Cc: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      35694b04
    • Sabrina Dubroca's avatar
      [stable-only] net: add length argument to skb_copy_and_csum_datagram_iovec · fa89ae55
      Sabrina Dubroca authored 
      Without this length argument, we can read past the end of the iovec in
memcpy_toiovec because we have no way of knowing the total length of the
iovec's buffers.

This is needed for stable kernels where 89c22d8c ("net: Fix skb
csum races when peeking") has been backported but that don't have the
ioviter conversion, which is almost all the stable trees <= 3.18.

This also fixes a kernel crash for NFS servers when the client uses
 -onfsvers=3,proto=udp to mount the export.
Signed-off-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Reviewed-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
[ luis: backported to 3.16:
  - dropped changes to net/rxrpc/ar-recvmsg.c ]
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      fa89ae55
    • Arad, Ronen's avatar
      netlink: Trim skb to alloc size to avoid MSG_TRUNC · 9a11693d
      Arad, Ronen authored 
      commit db65a3aa upstream.

netlink_dump() allocates skb based on the calculated min_dump_alloc or
a per socket max_recvmsg_len.
min_alloc_size is maximum space required for any single netdev
attributes as calculated by rtnl_calcit().
max_recvmsg_len tracks the user provided buffer to netlink_recvmsg.
It is capped at 16KiB.
The intention is to avoid small allocations and to minimize the number
of calls required to obtain dump information for all net devices.

netlink_dump packs as many small messages as could fit within an skb
that was sized for the largest single netdev information. The actual
space available within an skb is larger than what is requested. It could
be much larger and up to near 2x with align to next power of 2 approach.

Allowing netlink_dump to use all the space available within the
allocated skb increases the buffer size a user has to provide to avoid
truncaion (i.e. MSG_TRUNG flag set).

It was observed that with many VLANs configured on at least one netdev,
a larger buffer of near 64KiB was necessary to avoid "Message truncated"
error in "ip link" or "bridge [-c[ompressvlans]] vlan show" when
min_alloc_size was only little over 32KiB.

This patch trims skb to allocated size in order to allow the user to
avoid truncation with more reasonable buffer size.
Signed-off-by: default avatarRonen Arad <ronen.arad@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      9a11693d
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