linux-stable.git/fs/crypto, branch v4.14.331

fscrypt: don't ignore minor_hash when hash is 0

2021-07-20T14:17:45+00:00

commit 77f30bfcfcf484da7208affd6a9e63406420bf91 upstream.

When initializing a no-key name, fscrypt_fname_disk_to_usr() sets the
minor_hash to 0 if the (major) hash is 0.

This doesn't make sense because 0 is a valid hash code, so we shouldn't
ignore the filesystem-provided minor_hash in that case.  Fix this by
removing the special case for 'hash == 0'.

This is an old bug that appears to have originated when the encryption
code in ext4 and f2fs was moved into fs/crypto/.  The original ext4 and
f2fs code passed the hash by pointer instead of by value.  So
'if (hash)' actually made sense then, as it was checking whether a
pointer was NULL.  But now the hashes are passed by value, and
filesystems just pass 0 for any hashes they don't have.  There is no
need to handle this any differently from the hashes actually being 0.

It is difficult to reproduce this bug, as it only made a difference in
the case where a filename's 32-bit major hash happened to be 0.
However, it probably had the largest chance of causing problems on
ubifs, since ubifs uses minor_hash to do lookups of no-key names, in
addition to using it as a readdir cookie.  ext4 only uses minor_hash as
a readdir cookie, and f2fs doesn't use minor_hash at all.

Fixes: 0b81d0779072 ("fs crypto: move per-file encryption from f2fs tree to fs/crypto")
Cc:  # v4.6+
Link: https://lore.kernel.org/r/20210527235236.2376556-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

fscrypt: return -EXDEV for incompatible rename or link into encrypted dir

2020-11-05T10:06:52+00:00

commit f5e55e777cc93eae1416f0fa4908e8846b6d7825 upstream.

Currently, trying to rename or link a regular file, directory, or
symlink into an encrypted directory fails with EPERM when the source
file is unencrypted or is encrypted with a different encryption policy,
and is on the same mountpoint.  It is correct for the operation to fail,
but the choice of EPERM breaks tools like 'mv' that know to copy rather
than rename if they see EXDEV, but don't know what to do with EPERM.

Our original motivation for EPERM was to encourage users to securely
handle their data.  Encrypting files by "moving" them into an encrypted
directory can be insecure because the unencrypted data may remain in
free space on disk, where it can later be recovered by an attacker.
It's much better to encrypt the data from the start, or at least try to
securely delete the source data e.g. using the 'shred' program.

However, the current behavior hasn't been effective at achieving its
goal because users tend to be confused, hack around it, and complain;
see e.g. https://github.com/google/fscrypt/issues/76.  And in some cases
it's actually inconsistent or unnecessary.  For example, 'mv'-ing files
between differently encrypted directories doesn't work even in cases
where it can be secure, such as when in userspace the same passphrase
protects both directories.  Yet, you *can* already 'mv' unencrypted
files into an encrypted directory if the source files are on a different
mountpoint, even though doing so is often insecure.

There are probably better ways to teach users to securely handle their
files.  For example, the 'fscrypt' userspace tool could provide a
command that migrates unencrypted files into an encrypted directory,
acting like 'shred' on the source files and providing appropriate
warnings depending on the type of the source filesystem and disk.

Receiving errors on unimportant files might also force some users to
disable encryption, thus making the behavior counterproductive.  It's
desirable to make encryption as unobtrusive as possible.

Therefore, change the error code from EPERM to EXDEV so that tools
looking for EXDEV will fall back to a copy.

This, of course, doesn't prevent users from still doing the right things
to securely manage their files.  Note that this also matches the
behavior when a file is renamed between two project quota hierarchies;
so there's precedent for using EXDEV for things other than mountpoints.

xfstests generic/398 will require an update with this change.

[Rewritten from an earlier patch series by Michael Halcrow.]

Cc: Michael Halcrow 
Cc: Joe Richey 
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

fscrypt: clean up some BUG_ON()s in block encryption/decryption

2019-07-31T05:28:22+00:00

[ Upstream commit eeacfdc68a104967162dfcba60f53f6f5b62a334 ]

Replace some BUG_ON()s with WARN_ON_ONCE() and returning an error code,
and move the check for len divisible by FS_CRYPTO_BLOCK_SIZE into
fscrypt_crypt_block() so that it's done for both encryption and
decryption, not just encryption.

Reviewed-by: Chandan Rajendra 
Signed-off-by: Eric Biggers 
Signed-off-by: Sasha Levin

fscrypt: don't set policy for a dead directory

2019-07-21T07:04:29+00:00

commit 5858bdad4d0d0fc18bf29f34c3ac836e0b59441f upstream.

The directory may have been removed when entering
fscrypt_ioctl_set_policy().  If so, the empty_dir() check will return
error for ext4 file system.

ext4_rmdir() sets i_size = 0, then ext4_empty_dir() reports an error
because 'inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2)'.  If
the fs is mounted with errors=panic, it will trigger a panic issue.

Add the check IS_DEADDIR() to fix this problem.

Fixes: 9bd8212f981e ("ext4 crypto: add encryption policy and password salt support")
Cc:  # v4.1+
Signed-off-by: Hongjie Fang 
Signed-off-by: Eric Biggers 
Signed-off-by: Greg Kroah-Hartman

fscrypt: use unbound workqueue for decryption

2018-08-03T05:50:32+00:00

[ Upstream commit 36dd26e0c8d42699eeba87431246c07c28075bae ]

Improve fscrypt read performance by switching the decryption workqueue
from bound to unbound.  With the bound workqueue, when multiple bios
completed on the same CPU, they were decrypted on that same CPU.  But
with the unbound queue, they are now decrypted in parallel on any CPU.

Although fscrypt read performance can be tough to measure due to the
many sources of variation, this change is most beneficial when
decryption is slow, e.g. on CPUs without AES instructions.  For example,
I timed tarring up encrypted directories on f2fs.  On x86 with AES-NI
instructions disabled, the unbound workqueue improved performance by
about 25-35%, using 1 to NUM_CPUs jobs with 4 or 8 CPUs available.  But
with AES-NI enabled, performance was unchanged to within ~2%.

I also did the same test on a quad-core ARM CPU using xts-speck128-neon
encryption.  There performance was usually about 10% better with the
unbound workqueue, bringing it closer to the unencrypted speed.

The unbound workqueue may be worse in some cases due to worse locality,
but I think it's still the better default.  dm-crypt uses an unbound
workqueue by default too, so this change makes fscrypt match.

Signed-off-by: Eric Biggers 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

fscrypt: lock mutex before checking for bounce page pool

2017-11-30T08:40:44+00:00

commit a0b3bc855374c50b5ea85273553485af48caf2f7 upstream.

fscrypt_initialize(), which allocates the global bounce page pool when
an encrypted file is first accessed, uses "double-checked locking" to
try to avoid locking fscrypt_init_mutex.  However, it doesn't use any
memory barriers, so it's theoretically possible for a thread to observe
a bounce page pool which has not been fully initialized.  This is a
classic bug with "double-checked locking".

While "only a theoretical issue" in the latest kernel, in pre-4.8
kernels the pointer that was checked was not even the last to be
initialized, so it was easily possible for a crash (NULL pointer
dereference) to happen.  This was changed only incidentally by the large
refactor to use fs/crypto/.

Solve both problems in a trivial way that can easily be backported: just
always take the mutex.  It's theoretically less efficient, but it
shouldn't be noticeable in practice as the mutex is only acquired very
briefly once per encrypted file.

Later I'd like to make this use a helper macro like DO_ONCE().  However,
DO_ONCE() runs in atomic context, so we'd need to add a new macro that
allows blocking.

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

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

fscrypt: fix dereference of NULL user_key_payload

2017-10-12T16:16:40+00:00

When an fscrypt-encrypted file is opened, we request the file's master
key from the keyrings service as a logon key, then access its payload.
However, a revoked key has a NULL payload, and we failed to check for
this.  request_key() *does* skip revoked keys, but there is still a
window where the key can be revoked before we acquire its semaphore.

Fix it by checking for a NULL payload, treating it like a key which was
already revoked at the time it was requested.

Fixes: 88bd6ccdcdd6 ("ext4 crypto: add encryption key management facilities")
Reviewed-by: James Morris 
Cc:     [v4.1+]
Signed-off-by: Eric Biggers 
Signed-off-by: David Howells

block: replace bi_bdev with a gendisk pointer and partitions index

2017-08-23T18:49:55+00:00

This way we don't need a block_device structure to submit I/O.  The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open.  Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).

For the actual I/O path all that we need is the gendisk, which exists
once per block device.  But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.

Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2017-07-09T16:31:22+00:00

Pull ext4 updates from Ted Ts'o:
 "The first major feature for ext4 this merge window is the largedir
  feature, which allows ext4 directories to support over 2 billion
  directory entries (assuming ~64 byte file names; in practice, users
  will run into practical performance limits first.) This feature was
  originally written by the Lustre team, and credit goes to Artem
  Blagodarenko from Seagate for getting this feature upstream.

  The second major major feature allows ext4 to support extended
  attribute values up to 64k. This feature was also originally from
  Lustre, and has been enhanced by Tahsin Erdogan from Google with a
  deduplication feature so that if multiple files have the same xattr
  value (for example, Windows ACL's stored by Samba), only one copy will
  be stored on disk for encoding and caching efficiency.

  We also have the usual set of bug fixes, cleanups, and optimizations"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (47 commits)
  ext4: fix spelling mistake: "prellocated" -> "preallocated"
  ext4: fix __ext4_new_inode() journal credits calculation
  ext4: skip ext4_init_security() and encryption on ea_inodes
  fs: generic_block_bmap(): initialize all of the fields in the temp bh
  ext4: change fast symlink test to not rely on i_blocks
  ext4: require key for truncate(2) of encrypted file
  ext4: don't bother checking for encryption key in ->mmap()
  ext4: check return value of kstrtoull correctly in reserved_clusters_store
  ext4: fix off-by-one fsmap error on 1k block filesystems
  ext4: return EFSBADCRC if a bad checksum error is found in ext4_find_entry()
  ext4: return EIO on read error in ext4_find_entry
  ext4: forbid encrypting root directory
  ext4: send parallel discards on commit completions
  ext4: avoid unnecessary stalls in ext4_evict_inode()
  ext4: add nombcache mount option
  ext4: strong binding of xattr inode references
  ext4: eliminate xattr entry e_hash recalculation for removes
  ext4: reserve space for xattr entries/names
  quota: add get_inode_usage callback to transfer multi-inode charges
  ext4: xattr inode deduplication
  ...