linux-stable.git/fs, branch v3.14.70

get_rock_ridge_filename(): handle malformed NM entries

2016-05-19T00:03:59+00:00

commit 99d825822eade8d827a1817357cbf3f889a552d6 upstream.

Payloads of NM entries are not supposed to contain NUL.  When we run
into such, only the part prior to the first NUL goes into the
concatenation (i.e. the directory entry name being encoded by a bunch
of NM entries).  We do stop when the amount collected so far + the
claimed amount in the current NM entry exceed 254.  So far, so good,
but what we return as the total length is the sum of *claimed*
sizes, not the actual amount collected.  And that can grow pretty
large - not unlimited, since you'd need to put CE entries in
between to be able to get more than the maximum that could be
contained in one isofs directory entry / continuation chunk and
we are stop once we'd encountered 32 CEs, but you can get about 8Kb
easily.  And that's what will be passed to readdir callback as the
name length.  8Kb __copy_to_user() from a buffer allocated by
__get_free_page()

Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

proc: prevent accessing /proc//environ until it's ready

2016-05-11T09:21:01+00:00

commit 8148a73c9901a8794a50f950083c00ccf97d43b3 upstream.

If /proc//environ gets read before the envp[] array is fully set up
in create_{aout,elf,elf_fdpic,flat}_tables(), we might end up trying to
read more bytes than are actually written, as env_start will already be
set but env_end will still be zero, making the range calculation
underflow, allowing to read beyond the end of what has been written.

Fix this as it is done for /proc//cmdline by testing env_end for
zero.  It is, apparently, intentionally set last in create_*_tables().

This bug was found by the PaX size_overflow plugin that detected the
arithmetic underflow of 'this_len = env_end - (env_start + src)' when
env_end is still zero.

The expected consequence is that userland trying to access
/proc//environ of a not yet fully set up process may get
inconsistent data as we're in the middle of copying in the environment
variables.

Fixes: https://forums.grsecurity.net/viewtopic.php?f=3&t=4363
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=116461
Signed-off-by: Mathias Krause 
Cc: Emese Revfy 
Cc: Pax Team 
Cc: Al Viro 
Cc: Mateusz Guzik 
Cc: Alexey Dobriyan 
Cc: Cyrill Gorcunov 
Cc: Jarod Wilson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ext4: fix NULL pointer dereference in ext4_mark_inode_dirty()

2016-05-04T21:51:25+00:00

commit 5e1021f2b6dff1a86a468a1424d59faae2bc63c1 upstream.

ext4_reserve_inode_write() in ext4_mark_inode_dirty() could fail on
error (e.g. EIO) and iloc.bh can be NULL in this case. But the error is
ignored in the following "if" condition and ext4_expand_extra_isize()
might be called with NULL iloc.bh set, which triggers NULL pointer
dereference.

This is uncovered by commit 8b4953e13f4c ("ext4: reserve code points for
the project quota feature"), which enlarges the ext4_inode size, and
run the following script on new kernel but with old mke2fs:

  #/bin/bash
  mnt=/mnt/ext4
  devname=ext4-error
  dev=/dev/mapper/$devname
  fsimg=/home/fs.img

  trap cleanup 0 1 2 3 9 15

  cleanup()
  {
          umount $mnt >/dev/null 2>&1
          dmsetup remove $devname
          losetup -d $backend_dev
          rm -f $fsimg
          exit 0
  }

  rm -f $fsimg
  fallocate -l 1g $fsimg
  backend_dev=`losetup -f --show $fsimg`
  devsize=`blockdev --getsz $backend_dev`

  good_tab="0 $devsize linear $backend_dev 0"
  error_tab="0 $devsize error $backend_dev 0"

  dmsetup create $devname --table "$good_tab"

  mkfs -t ext4 $dev
  mount -t ext4 -o errors=continue,strictatime $dev $mnt

  dmsetup load $devname --table "$error_tab" && dmsetup resume $devname
  echo 3 > /proc/sys/vm/drop_caches
  ls -l $mnt
  exit 0

[ Patch changed to simplify the function a tiny bit. -- Ted ]

Signed-off-by: Eryu Guan 
Signed-off-by: Theodore Ts'o 
Cc: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

ext4: add lockdep annotations for i_data_sem

2016-04-20T06:40:44+00:00

commit daf647d2dd58cec59570d7698a45b98e580f2076 upstream.

With the internal Quota feature, mke2fs creates empty quota inodes and
quota usage tracking is enabled as soon as the file system is mounted.
Since quotacheck is no longer preallocating all of the blocks in the
quota inode that are likely needed to be written to, we are now seeing
a lockdep false positive caused by needing to allocate a quota block
from inside ext4_map_blocks(), while holding i_data_sem for a data
inode.  This results in this complaint:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&ei->i_data_sem);
                                lock(&s->s_dquot.dqio_mutex);
                                lock(&ei->i_data_sem);
   lock(&s->s_dquot.dqio_mutex);

Google-Bug-Id: 27907753

Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ocfs2/dlm: fix BUG in dlm_move_lockres_to_recovery_list

2016-04-12T16:12:48+00:00

commit be12b299a83fc807bbaccd2bcb8ec50cbb0cb55c upstream.

When master handles convert request, it queues ast first and then
returns status.  This may happen that the ast is sent before the request
status because the above two messages are sent by two threads.  And
right after the ast is sent, if master down, it may trigger BUG in
dlm_move_lockres_to_recovery_list in the requested node because ast
handler moves it to grant list without clear lock->convert_pending.  So
remove BUG_ON statement and check if the ast is processed in
dlmconvert_remote.

Signed-off-by: Joseph Qi 
Reported-by: Yiwen Jiang 
Cc: Junxiao Bi 
Cc: Mark Fasheh 
Cc: Joel Becker 
Cc: Tariq Saeed 
Cc: Junxiao Bi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ocfs2/dlm: fix race between convert and recovery

2016-04-12T16:12:48+00:00

commit ac7cf246dfdbec3d8fed296c7bf30e16f5099dac upstream.

There is a race window between dlmconvert_remote and
dlm_move_lockres_to_recovery_list, which will cause a lock with
OCFS2_LOCK_BUSY in grant list, thus system hangs.

dlmconvert_remote
{
        spin_lock(&res->spinlock);
        list_move_tail(&lock->list, &res->converting);
        lock->convert_pending = 1;
        spin_unlock(&res->spinlock);

        status = dlm_send_remote_convert_request();
        >>>>>> race window, master has queued ast and return DLM_NORMAL,
               and then down before sending ast.
               this node detects master down and calls
               dlm_move_lockres_to_recovery_list, which will revert the
               lock to grant list.
               Then OCFS2_LOCK_BUSY won't be cleared as new master won't
               send ast any more because it thinks already be authorized.

        spin_lock(&res->spinlock);
        lock->convert_pending = 0;
        if (status != DLM_NORMAL)
                dlm_revert_pending_convert(res, lock);
        spin_unlock(&res->spinlock);
}

In this case, check if res->state has DLM_LOCK_RES_RECOVERING bit set
(res is still in recovering) or res master changed (new master has
finished recovery), reset the status to DLM_RECOVERING, then it will
retry convert.

Signed-off-by: Joseph Qi 
Reported-by: Yiwen Jiang 
Reviewed-by: Junxiao Bi 
Cc: Mark Fasheh 
Cc: Joel Becker 
Cc: Tariq Saeed 
Cc: Junxiao Bi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

fs/coredump: prevent fsuid=0 dumps into user-controlled directories

2016-04-12T16:12:47+00:00

commit 378c6520e7d29280f400ef2ceaf155c86f05a71a upstream.

This commit fixes the following security hole affecting systems where
all of the following conditions are fulfilled:

 - The fs.suid_dumpable sysctl is set to 2.
 - The kernel.core_pattern sysctl's value starts with "/". (Systems
   where kernel.core_pattern starts with "|/" are not affected.)
 - Unprivileged user namespace creation is permitted. (This is
   true on Linux >=3.8, but some distributions disallow it by
   default using a distro patch.)

Under these conditions, if a program executes under secure exec rules,
causing it to run with the SUID_DUMP_ROOT flag, then unshares its user
namespace, changes its root directory and crashes, the coredump will be
written using fsuid=0 and a path derived from kernel.core_pattern - but
this path is interpreted relative to the root directory of the process,
allowing the attacker to control where a coredump will be written with
root privileges.

To fix the security issue, always interpret core_pattern for dumps that
are written under SUID_DUMP_ROOT relative to the root directory of init.

Signed-off-by: Jann Horn 
Acked-by: Kees Cook 
Cc: Al Viro 
Cc: "Eric W. Biederman" 
Cc: Andy Lutomirski 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

xfs: fix two memory leaks in xfs_attr_list.c error paths

2016-04-12T16:12:46+00:00

commit 2e83b79b2d6c78bf1b4aa227938a214dcbddc83f upstream.

This plugs 2 trivial leaks in xfs_attr_shortform_list and
xfs_attr3_leaf_list_int.

Signed-off-by: Mateusz Guzik 
Reviewed-by: Eric Sandeen 
Signed-off-by: Dave Chinner 
Signed-off-by: Greg Kroah-Hartman

splice: handle zero nr_pages in splice_to_pipe()

2016-04-12T16:12:46+00:00

commit d6785d9152147596f60234157da2b02540c3e60f upstream.

Running the following command:

 busybox cat /sys/kernel/debug/tracing/trace_pipe > /dev/null

with any tracing enabled pretty very quickly leads to various NULL
pointer dereferences and VM BUG_ON()s, such as these:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
 IP: [] generic_pipe_buf_release+0xc/0x40
 Call Trace:
  [] splice_direct_to_actor+0x143/0x1e0
  [] ? generic_pipe_buf_nosteal+0x10/0x10
  [] do_splice_direct+0x8f/0xb0
  [] do_sendfile+0x199/0x380
  [] SyS_sendfile64+0x90/0xa0
  [] entry_SYSCALL_64_fastpath+0x12/0x6d

 page dumped because: VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0)
 kernel BUG at include/linux/mm.h:367!
 invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
 RIP: [] generic_pipe_buf_release+0x3c/0x40
 Call Trace:
  [] splice_direct_to_actor+0x143/0x1e0
  [] ? generic_pipe_buf_nosteal+0x10/0x10
  [] do_splice_direct+0x8f/0xb0
  [] do_sendfile+0x199/0x380
  [] SyS_sendfile64+0x90/0xa0
  [] tracesys_phase2+0x84/0x89

(busybox's cat uses sendfile(2), unlike the coreutils version)

This is because tracing_splice_read_pipe() can call splice_to_pipe()
with spd->nr_pages == 0.  spd_pages underflows in splice_to_pipe() and
we fill the page pointers and the other fields of the pipe_buffers with
garbage.

All other callers of splice_to_pipe() avoid calling it when nr_pages ==
0, and we could make tracing_splice_read_pipe() do that too, but it
seems reasonable to have splice_to_page() handle this condition
gracefully.

Signed-off-by: Rabin Vincent 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

jbd2: fix FS corruption possibility in jbd2_journal_destroy() on umount path

2016-04-12T16:12:46+00:00

commit c0a2ad9b50dd80eeccd73d9ff962234590d5ec93 upstream.

On umount path, jbd2_journal_destroy() writes latest transaction ID
(->j_tail_sequence) to be used at next mount.

The bug is that ->j_tail_sequence is not holding latest transaction ID
in some cases. So, at next mount, there is chance to conflict with
remaining (not overwritten yet) transactions.

	mount (id=10)
	write transaction (id=11)
	write transaction (id=12)
	umount (id=10) <= the bug doesn't write latest ID

	mount (id=10)
	write transaction (id=11)
	crash

	mount
	[recovery process]
		transaction (id=11)
		transaction (id=12) <= valid transaction ID, but old commit
                                       must not replay

Like above, this bug become the cause of recovery failure, or FS
corruption.

So why ->j_tail_sequence doesn't point latest ID?

Because if checkpoint transactions was reclaimed by memory pressure
(i.e. bdev_try_to_free_page()), then ->j_tail_sequence is not updated.
(And another case is, __jbd2_journal_clean_checkpoint_list() is called
with empty transaction.)

So in above cases, ->j_tail_sequence is not pointing latest
transaction ID at umount path. Plus, REQ_FLUSH for checkpoint is not
done too.

So, to fix this problem with minimum changes, this patch updates
->j_tail_sequence, and issue REQ_FLUSH.  (With more complex changes,
some optimizations would be possible to avoid unnecessary REQ_FLUSH
for example though.)

BTW,

	journal->j_tail_sequence =
		++journal->j_transaction_sequence;

Increment of ->j_transaction_sequence seems to be unnecessary, but
ext3 does this.

Signed-off-by: OGAWA Hirofumi 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman