linux-stable.git/include/linux/fs.h, branch v4.5.3

fs: add file_dentry()

2016-04-20T06:45:23+00:00

commit d101a125954eae1d397adda94ca6319485a50493 upstream.

This series fixes bugs in nfs and ext4 due to 4bacc9c9234c ("overlayfs:
Make f_path always point to the overlay and f_inode to the underlay").

Regular files opened on overlayfs will result in the file being opened on
the underlying filesystem, while f_path points to the overlayfs
mount/dentry.

This confuses filesystems which get the dentry from struct file and assume
it's theirs.

Add a new helper, file_dentry() [*], to get the filesystem's own dentry
from the file.  This checks file->f_path.dentry->d_flags against
DCACHE_OP_REAL, and returns file->f_path.dentry if DCACHE_OP_REAL is not
set (this is the common, non-overlayfs case).

In the uncommon case it will call into overlayfs's ->d_real() to get the
underlying dentry, matching file_inode(file).

The reason we need to check against the inode is that if the file is copied
up while being open, d_real() would return the upper dentry, while the open
file comes from the lower dentry.

[*] If possible, it's better simply to use file_inode() instead.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Theodore Ts'o 
Tested-by: Goldwyn Rodrigues 
Reviewed-by: Trond Myklebust 
Cc: David Howells 
Cc: Al Viro 
Cc: Daniel Axtens 
Signed-off-by: Greg Kroah-Hartman

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

2016-04-12T14:33:40+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

block: revert runtime dax control of the raw block device

2016-01-30T21:35:31+00:00

Dynamically enabling DAX requires that the page cache first be flushed
and invalidated.  This must occur atomically with the change of DAX mode
otherwise we confuse the fsync/msync tracking and violate data
durability guarantees.  Eliminate the possibilty of DAX-disabled to
DAX-enabled transitions for now and revisit this for the next cycle.

Cc: Jan Kara 
Cc: Jeff Moyer 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Matthew Wilcox 
Cc: Andrew Morton 
Cc: Ross Zwisler 
Signed-off-by: Dan Williams

fs, block: force direct-I/O for dax-enabled block devices

2016-01-30T21:33:59+00:00

Similar to the file I/O path, re-direct all I/O to the DAX path for I/O
to a block-device special file.  Both regular files and device special
files can use the common filp->f_mapping->host lookup to determing is
DAX is enabled.

Otherwise, we confuse the DAX code that does not expect to find live
data in the page cache:

    ------------[ cut here ]------------
    WARNING: CPU: 0 PID: 7676 at mm/filemap.c:217
    __delete_from_page_cache+0x9f6/0xb60()
    Modules linked in:
    CPU: 0 PID: 7676 Comm: a.out Not tainted 4.4.0+ #276
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
     00000000ffffffff ffff88006d3f7738 ffffffff82999e2d 0000000000000000
     ffff8800620a0000 ffffffff86473d20 ffff88006d3f7778 ffffffff81352089
     ffffffff81658d36 ffffffff86473d20 00000000000000d9 ffffea0000009d60
    Call Trace:
     [<     inline     >] __dump_stack lib/dump_stack.c:15
     [] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
     [] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482
     [] warn_slowpath_null+0x29/0x30 kernel/panic.c:515
     [] __delete_from_page_cache+0x9f6/0xb60 mm/filemap.c:217
     [] delete_from_page_cache+0x112/0x200 mm/filemap.c:244
     [] __dax_fault+0x859/0x1800 fs/dax.c:487
     [] blkdev_dax_fault+0x26/0x30 fs/block_dev.c:1730
     [<     inline     >] wp_pfn_shared mm/memory.c:2208
     [] do_wp_page+0xc85/0x14f0 mm/memory.c:2307
     [<     inline     >] handle_pte_fault mm/memory.c:3323
     [<     inline     >] __handle_mm_fault mm/memory.c:3417
     [] handle_mm_fault+0x2483/0x4640 mm/memory.c:3446
     [] __do_page_fault+0x376/0x960 arch/x86/mm/fault.c:1238
     [] trace_do_page_fault+0xe8/0x420 arch/x86/mm/fault.c:1331
     [] do_async_page_fault+0x14/0xd0 arch/x86/kernel/kvm.c:264
     [] async_page_fault+0x28/0x30 arch/x86/entry/entry_64.S:986
     [] entry_SYSCALL_64_fastpath+0x16/0x7a
    arch/x86/entry/entry_64.S:185
    ---[ end trace dae21e0f85f1f98c ]---

Fixes: 5a023cdba50c ("block: enable dax for raw block devices")
Reported-by: Dmitry Vyukov 
Reported-by: Kirill A. Shutemov 
Suggested-by: Jan Kara 
Reviewed-by: Jan Kara 
Suggested-by: Matthew Wilcox 
Tested-by: Ross Zwisler 
Signed-off-by: Dan Williams

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-01-23T20:24:56+00:00

Pull final vfs updates from Al Viro:

 - The ->i_mutex wrappers (with small prereq in lustre)

 - a fix for too early freeing of symlink bodies on shmem (they need to
   be RCU-delayed) (-stable fodder)

 - followup to dedupe stuff merged this cycle

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: abort dedupe loop if fatal signals are pending
  make sure that freeing shmem fast symlinks is RCU-delayed
  wrappers for ->i_mutex access
  lustre: remove unused declaration

dax: support dirty DAX entries in radix tree

2016-01-23T01:02:18+00:00

Add support for tracking dirty DAX entries in the struct address_space
radix tree.  This tree is already used for dirty page writeback, and it
already supports the use of exceptional (non struct page*) entries.

In order to properly track dirty DAX pages we will insert new
exceptional entries into the radix tree that represent dirty DAX PTE or
PMD pages.  These exceptional entries will also contain the writeback
addresses for the PTE or PMD faults that we can use at fsync/msync time.

There are currently two types of exceptional entries (shmem and shadow)
that can be placed into the radix tree, and this adds a third.  We rely
on the fact that only one type of exceptional entry can be found in a
given radix tree based on its usage.  This happens for free with DAX vs
shmem but we explicitly prevent shadow entries from being added to radix
trees for DAX mappings.

The only shadow entries that would be generated for DAX radix trees
would be to track zero page mappings that were created for holes.  These
pages would receive minimal benefit from having shadow entries, and the
choice to have only one type of exceptional entry in a given radix tree
makes the logic simpler both in clear_exceptional_entry() and in the
rest of DAX.

Signed-off-by: Ross Zwisler 
Cc: "H. Peter Anvin" 
Cc: "J. Bruce Fields" 
Cc: "Theodore Ts'o" 
Cc: Alexander Viro 
Cc: Andreas Dilger 
Cc: Dave Chinner 
Cc: Ingo Molnar 
Cc: Jan Kara 
Cc: Jeff Layton 
Cc: Matthew Wilcox 
Cc: Thomas Gleixner 
Cc: Dan Williams 
Cc: Matthew Wilcox 
Cc: Dave Hansen 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

wrappers for ->i_mutex access

2016-01-22T23:04:28+00:00

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro

Merge tag 'libnvdimm-for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2016-01-14T03:15:14+00:00

Pull libnvdimm updates from Dan Williams:
 "The bulk of this has appeared in -next and independently received a
  build success notification from the kbuild robot.  The 'for-4.5/block-
  dax' topic branch was rebased over the weekend to drop the "block
  device end-of-life" rework that Al would like to see re-implemented
  with a notifier, and to address bug reports against the badblocks
  integration.

  There is pending feedback against "libnvdimm: Add a poison list and
  export badblocks" received last week.  Linda identified some localized
  fixups that we will handle incrementally.

  Summary:

   - Media error handling: The 'badblocks' implementation that
     originated in md-raid is up-levelled to a generic capability of a
     block device.  This initial implementation is limited to being
     consulted in the pmem block-i/o path.  Later, 'badblocks' will be
     consulted when creating dax mappings.

   - Raw block device dax: For virtualization and other cases that want
     large contiguous mappings of persistent memory, add the capability
     to dax-mmap a block device directly.

   - Increased /dev/mem restrictions: Add an option to treat all
     io-memory as IORESOURCE_EXCLUSIVE, i.e. disable /dev/mem access
     while a driver is actively using an address range.  This behavior
     is controlled via the new CONFIG_IO_STRICT_DEVMEM option and can be
     overridden by the existing "iomem=relaxed" kernel command line
     option.

   - Miscellaneous fixes include a 'pfn'-device huge page alignment fix,
     block device shutdown crash fix, and other small libnvdimm fixes"

* tag 'libnvdimm-for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (32 commits)
  block: kill disk_{check|set|clear|alloc}_badblocks
  libnvdimm, pmem: nvdimm_read_bytes() badblocks support
  pmem, dax: disable dax in the presence of bad blocks
  pmem: fail io-requests to known bad blocks
  libnvdimm: convert to statically allocated badblocks
  libnvdimm: don't fail init for full badblocks list
  block, badblocks: introduce devm_init_badblocks
  block: clarify badblocks lifetime
  badblocks: rename badblocks_free to badblocks_exit
  libnvdimm, pmem: move definition of nvdimm_namespace_add_poison to nd.h
  libnvdimm: Add a poison list and export badblocks
  nfit_test: Enable DSMs for all test NFITs
  md: convert to use the generic badblocks code
  block: Add badblock management for gendisks
  badblocks: Add core badblock management code
  block: fix del_gendisk() vs blkdev_ioctl crash
  block: enable dax for raw block devices
  block: introduce bdev_file_inode()
  restrict /dev/mem to idle io memory ranges
  arch: consolidate CONFIG_STRICT_DEVM in lib/Kconfig.debug
  ...

Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-01-13T01:11:47+00:00

Pull misc vfs updates from Al Viro:
 "All kinds of stuff.  That probably should've been 5 or 6 separate
  branches, but by the time I'd realized how large and mixed that bag
  had become it had been too close to -final to play with rebasing.

  Some fs/namei.c cleanups there, memdup_user_nul() introduction and
  switching open-coded instances, burying long-dead code, whack-a-mole
  of various kinds, several new helpers for ->llseek(), assorted
  cleanups and fixes from various people, etc.

  One piece probably deserves special mention - Neil's
  lookup_one_len_unlocked().  Similar to lookup_one_len(), but gets
  called without ->i_mutex and tries to avoid ever taking it.  That, of
  course, means that it's not useful for any directory modifications,
  but things like getting inode attributes in nfds readdirplus are fine
  with that.  I really should've asked for moratorium on lookup-related
  changes this cycle, but since I hadn't done that early enough...  I
  *am* asking for that for the coming cycle, though - I'm going to try
  and get conversion of i_mutex to rwsem with ->lookup() done under lock
  taken shared.

  There will be a patch closer to the end of the window, along the lines
  of the one Linus had posted last May - mechanical conversion of
  ->i_mutex accesses to inode_lock()/inode_unlock()/inode_trylock()/
  inode_is_locked()/inode_lock_nested().  To quote Linus back then:

    -----
    |    This is an automated patch using
    |
    |        sed 's/mutex_lock(&\(.*\)->i_mutex)/inode_lock(\1)/'
    |        sed 's/mutex_unlock(&\(.*\)->i_mutex)/inode_unlock(\1)/'
    |        sed 's/mutex_lock_nested(&\(.*\)->i_mutex,[     ]*I_MUTEX_\([A-Z0-9_]*\))/inode_lock_nested(\1, I_MUTEX_\2)/'
    |        sed 's/mutex_is_locked(&\(.*\)->i_mutex)/inode_is_locked(\1)/'
    |        sed 's/mutex_trylock(&\(.*\)->i_mutex)/inode_trylock(\1)/'
    |
    |    with a very few manual fixups
    -----

  I'm going to send that once the ->i_mutex-affecting stuff in -next
  gets mostly merged (or when Linus says he's about to stop taking
  merges)"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  nfsd: don't hold i_mutex over userspace upcalls
  fs:affs:Replace time_t with time64_t
  fs/9p: use fscache mutex rather than spinlock
  proc: add a reschedule point in proc_readfd_common()
  logfs: constify logfs_block_ops structures
  fcntl: allow to set O_DIRECT flag on pipe
  fs: __generic_file_splice_read retry lookup on AOP_TRUNCATED_PAGE
  fs: xattr: Use kvfree()
  [s390] page_to_phys() always returns a multiple of PAGE_SIZE
  nbd: use ->compat_ioctl()
  fs: use block_device name vsprintf helper
  lib/vsprintf: add %*pg format specifier
  fs: use gendisk->disk_name where possible
  poll: plug an unused argument to do_poll
  amdkfd: don't open-code memdup_user()
  cdrom: don't open-code memdup_user()
  rsxx: don't open-code memdup_user()
  mtip32xx: don't open-code memdup_user()
  [um] mconsole: don't open-code memdup_user_nul()
  [um] hostaudio: don't open-code memdup_user()
  ...

Merge branch 'work.copy_file_range' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-01-13T00:30:34+00:00

Pull vfs copy_file_range updates from Al Viro:
 "Several series around copy_file_range/CLONE"

* 'work.copy_file_range' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  btrfs: use new dedupe data function pointer
  vfs: hoist the btrfs deduplication ioctl to the vfs
  vfs: wire up compat ioctl for CLONE/CLONE_RANGE
  cifs: avoid unused variable and label
  nfsd: implement the NFSv4.2 CLONE operation
  nfsd: Pass filehandle to nfs4_preprocess_stateid_op()
  vfs: pull btrfs clone API to vfs layer
  locks: new locks_mandatory_area calling convention
  vfs: Add vfs_copy_file_range() support for pagecache copies
  btrfs: add .copy_file_range file operation
  x86: add sys_copy_file_range to syscall tables
  vfs: add copy_file_range syscall and vfs helper