fscrypt: Allow modular crypto algorithms

The commit 643fa9612bf1 ("fscrypt: remove filesystem specific
build config option") removed modular support for fs/crypto. This
causes the Crypto API to be built-in whenever fscrypt is enabled.
This makes it very difficult for me to test modular builds of
the Crypto API without disabling fscrypt which is a pain.

As fscrypt is still evolving and it's developing new ties with the
fs layer, it's hard to build it as a module for now.

However, the actual algorithms are not required until a filesystem
is mounted. Therefore we can allow them to be built as modules.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Link: https://lore.kernel.org/r/20191227024700.7vrzuux32uyfdgum@gondor.apana.org.au
Signed-off-by: Eric Biggers <ebiggers@google.com>

ubifs: Add support for zstd compression.

zstd shows a good compression rate and is faster than lzo,
also on slow ARM cores.

Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Michele Dionisio <michele.dionisio@gmail.com>
[rw: rewrote commit message]
Signed-off-by: Richard Weinberger <richard@nod.at>

ubifs: support offline signed images

HMACs can only be generated on the system the UBIFS image is running on.
To support offline signed images we add a PKCS#7 signature to the UBIFS
image which can be created by mkfs.ubifs.

Both the master node and the superblock need to be authenticated, during
normal runtime both are protected with HMACs. For offline signature
support however only a single signature is desired. We add a signature
covering the superblock node directly behind it. To protect the master
node a hash of the master node is added to the superblock which is used
when the master node doesn't contain a HMAC.

Transition to a read/write filesystem is also supported. During
transition first the master node is rewritten with a HMAC (implicitly,
it is written anyway as the FS is marked dirty). Afterwards the
superblock is rewritten with a HMAC. Once after the image has been
mounted read/write it is HMAC only, the signature is no longer required
or even present on the filesystem.

In an offline signed image the master node is authenticated by the
superblock. In a transition to r/w we have to make sure that the master
node is rewritten before the superblock node. In this case the master
node gets a HMAC and its authenticity no longer depends on the
superblock node. There are some cases in which the current code first
writes the superblock node though, so with this patch writing of the
superblock node is delayed until the master node is written.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fscrypt: remove filesystem specific build config option

In order to have a common code base for fscrypt "post read" processing
for all filesystems which support encryption, this commit removes
filesystem specific build config option (e.g. CONFIG_EXT4_FS_ENCRYPTION)
and replaces it with a build option (i.e. CONFIG_FS_ENCRYPTION) whose
value affects all the filesystems making use of fscrypt.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>

ubifs: auth: Add CONFIG_KEYS dependency

The new authentication support causes a build failure
when CONFIG_KEYS is disabled, so add a dependency.

fs/ubifs/auth.c: In function 'ubifs_init_authentication':
fs/ubifs/auth.c:249:16: error: implicit declaration of function 'request_key'; did you mean 'request_irq'? [-Werror=implicit-function-declaration]
keyring_key = request_key(&key_type_logon, c->auth_key_name, NULL);

Fixes: d8a22773a12c ("ubifs: Enable authentication support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubifs: CONFIG_UBIFS_FS_AUTHENTICATION should depend on UBIFS_FS

Instead of adding yet another dependency on UBIFS_FS, wrap the whole
block of ubifs config options in a single "if UBIFS_FS".

Fixes: d8a22773a12c6d78 ("ubifs: Enable authentication support")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubifs: Enable authentication support

With the preparations all being done this patch now enables authentication
support for UBIFS. Authentication is enabled when the newly introduced
auth_key and auth_hash_name mount options are passed. auth_key provides
the key which is used for authentication whereas auth_hash_name provides
the hashing algorithm used for this FS. Passing these options make
authentication mandatory and only UBIFS images that can be authenticated
with the given key are allowed.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubifs: Add helper functions for authentication support

This patch adds the various helper functions needed for authentication
support. We need functions to hash nodes, to embed HMACs into a node and
to compare hashes and HMACs. Most functions first check if this
filesystem is authenticated and bail out early if not, which makes the
functions safe to be called with disabled authentication.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubifs: introduce Kconfig symbol for xattr support

Allow to disable extended attribute support.

This aids in reliability testing, especially since some xattr
related bugs have surfaced.

Also an embedded system might not need it, so this allows for a
slightly smaller kernel (about 4KiB).

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubifs: Add CONFIG_UBIFS_FS_SECURITY to disable/enable security labels

When write syscall is called, every time security label is searched to
determine that file's privileges should be changed.
If LSM(Linux Security Model) is not used, this is useless.

So introduce CONFIG_UBIFS_SECURITY to disable security labels. it's default
value is "y".

Signed-off-by: Hyunchul Lee <cheol.lee@lge.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubifs: add CONFIG_BLOCK dependency for encryption

This came up during the v4.10 merge window:

warning: (UBIFS_FS_ENCRYPTION) selects FS_ENCRYPTION which has unmet direct dependencies (BLOCK)
fs/crypto/crypto.c: In function 'fscrypt_zeroout_range':
fs/crypto/crypto.c:355:9: error: implicit declaration of function 'bio_alloc';did you mean 'd_alloc'? [-Werror=implicit-function-declaration]
bio = bio_alloc(GFP_NOWAIT, 1);

The easiest way out is to limit UBIFS_FS_ENCRYPTION to configurations
that also enable BLOCK.

Fixes: d475a507457b ("ubifs: Add skeleton for fscrypto")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

ubifs: Add skeleton for fscrypto

This is the first building block to provide file level
encryption on UBIFS.

Signed-off-by: Richard Weinberger <richard@nod.at>

ubifs: introduce UBIFS_ATIME_SUPPORT to ubifs

To make ubifs support atime flexily, this commit introduces
a Kconfig option named as UBIFS_ATIME_SUPPORT.

With UBIFS_ATIME_SUPPORT=n:
ubifs keeps the full compatibility to no_atime from
the start of ubifs.

=================UBIFS_ATIME_SUPPORT=n=======================
-o - no atime
-o atime - no atime
-o noatime - no atime
-o relatime - no atime
-o strictatime - no atime
-o lazyatime - no atime

With UBIFS_ATIME_SUPPORT=y:
ubifs supports the atime same with other main stream
file systems.
=================UBIFS_ATIME_SUPPORT=y=======================
-o - default behavior (relatime currently)
-o atime - atime support
-o noatime - no atime support
-o relatime - relative atime support
-o strictatime - strict atime support
-o lazyatime - lazy atime support

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Richard Weinberger <richard@nod.at>

UBIFS: remove Kconfig debugging option

Have the debugging stuff always compiled-in instead. It simplifies maintanance
a lot.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBIFS: remove xattr Kconnfig option

Remove CONFIG_UBIFS_FS_XATTR configuration option and associated
UBIFS_FS_XATTR ifdefs.

Testing:
Tested using integck while using nandsim on x86 & MX28 based
platform with Micron MT29F2G08ABAEAH4 nand.

Signed-off-by: Subodh Nijsure <snijsure@grid-net.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

UBIFS: do not select KALLSYMS_ALL

All UBIFS needs is to make sure we stacktraces when UBIFS debugging
is enabled. It is enough to select KALLSYMS for this, KALLSYMS_ALL
is not necessary. Moreover, Randy Dunlap reported that UBIFS causes
the following Kconfig dependency warning:

warning: (UBIFS_FS_DEBUG && LOCKDEP && LATENCYTOP) selects KALLSYMS_ALL
which has unmet direct dependencies (DEBUG_KERNEL && KALLSYMS)

The reason is that KALLSYMS_ALL requires DEBUG_KERNEL and KALLSYMS, so
ideally, to select KALLSYMS_ALL we'd need to select DEBUG_KERNEL and
KALLSYMS first.

This seems to be too much to select. The easiest way to go is to forget
about KALLSYMS_ALL and just select KALLSYMS when UBIFS debugging is
enabled - that should be enough for stackdumps.

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>

UBIFS: kill CONFIG_UBIFS_FS_DEBUG_CHKS

Simplify UBIFS configuration menu and kill the option to enable self-check
compile-time. We do not really need this because we can do this run-time
using the module parameters or the corresponding sysfs interfaces. And
there is a value in simplifying the kernel configuration menu which becomes
increasingly large.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

UBIFS: simplify UBIFS Kconfig menu

Remove debug message level and debug checks Kconfig options as they
proved to be useless anyway. We have sysfs interface which we can
use for fine-grained debugging messages and checks selection, see
Documentation/filesystems/ubifs.txt for mode details.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

Revert "lib: build list_sort() only if needed"

This reverts commit a069c266ae5fdfbf5b4aecf2c672413aa33b2504.

It turns ou that not only was it missing a case (XFS) that needed it,
but perhaps more importantly, people sometimes want to enable new
modules that they hadn't had enabled before, and if such a module uses
list_sort(), it can't easily be inserted any more.

So rather than add a "select LIST_SORT" to the XFS case, just leave it
compiled in. It's not all _that_ big, after all, and the inconvenience
isn't worth it.

Requested-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Don Mullis <don.mullis@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib: build list_sort() only if needed

Build list_sort() only for configs that need it -- those that don't save
~581 bytes (i386).

Signed-off-by: Don Mullis <don.mullis@gmail.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

trivial: fix typos/grammar errors in Kconfig texts

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

trivial: fix then -> than typos in comments and documentation

- (better, more, bigger ...) then -> (...) than

Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

UBIFS: include to compilation

Add UBIFS to Makefile and Kbuild.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>