To achieve more comprehensive crypto test coverage, I'd like to add fuzz
tests that use random data layouts and request flags.

To be most effective these tests should be part of testmgr, so they
automatically run on every algorithm registered with the crypto API.
However, they will take much longer to run than the current tests and
therefore will only really be intended to be run by developers, whereas
the current tests have a wider audience.

Therefore, add a new kconfig option CONFIG_CRYPTO_MANAGER_EXTRA_TESTS
that can be set by developers to enable these extra, expensive tests.

Similar to the regular tests, also add a module parameter
cryptomgr.noextratests to support disabling the tests.

Finally, another module parameter cryptomgr.fuzz_iterations is added to
control how many iterations the fuzz tests do.  Note: for now setting
this to 0 will be equivalent to cryptomgr.noextratests=1.  But I opted
for separate parameters to provide more flexibility to add other types
of tests under the "extra tests" category in the future.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Fix typo "plcmul" to "pclmul"

Signed-off-by: Huaxuan Mao <minhaco@msn.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Pull Kconfig updates from Masahiro Yamada:

 - support -y option for merge_config.sh to avoid downgrading =y to =m

 - remove S_OTHER symbol type, and touch include/config/*.h files correctly

 - fix file name and line number in lexer warnings

 - fix memory leak when EOF is encountered in quotation

 - resolve all shift/reduce conflicts of the parser

 - warn no new line at end of file

 - make 'source' statement more strict to take only string literal

 - rewrite the lexer and remove the keyword lookup table

 - convert to SPDX License Identifier

 - compile C files independently instead of including them from zconf.y

 - fix various warnings of gconfig

 - misc cleanups

* tag 'kconfig-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits)
  kconfig: surround dbg_sym_flags with #ifdef DEBUG to fix gconf warning
  kconfig: split images.c out of qconf.cc/gconf.c to fix gconf warnings
  kconfig: add static qualifiers to fix gconf warnings
  kconfig: split the lexer out of zconf.y
  kconfig: split some C files out of zconf.y
  kconfig: convert to SPDX License Identifier
  kconfig: remove keyword lookup table entirely
  kconfig: update current_pos in the second lexer
  kconfig: switch to ASSIGN_VAL state in the second lexer
  kconfig: stop associating kconf_id with yylval
  kconfig: refactor end token rules
  kconfig: stop supporting '.' and '/' in unquoted words
  treewide: surround Kconfig file paths with double quotes
  microblaze: surround string default in Kconfig with double quotes
  kconfig: use T_WORD instead of T_VARIABLE for variables
  kconfig: use specific tokens instead of T_ASSIGN for assignments
  kconfig: refactor scanning and parsing "option" properties
  kconfig: use distinct tokens for type and default properties
  kconfig: remove redundant token defines
  kconfig: rename depends_list to comment_option_list
  ...

The Kconfig lexer supports special characters such as '.' and '/' in
the parameter context. In my understanding, the reason is just to
support bare file paths in the source statement.

I do not see a good reason to complicate Kconfig for the room of
ambiguity.

The majority of code already surrounds file paths with double quotes,
and it makes sense since file paths are constant string literals.

Make it treewide consistent now.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Ingo Molnar <mingo@kernel.org>

Now that the x86_64 SIMD implementations of ChaCha20 and XChaCha20 have
been refactored to support varying the number of rounds, add support for
XChaCha12.  This is identical to XChaCha20 except for the number of
rounds, which is 12 instead of 20.  This can be used by Adiantum.

Reviewed-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Add an XChaCha20 implementation that is hooked up to the x86_64 SIMD
implementations of ChaCha20.  This can be used by Adiantum.

An SSSE3 implementation of single-block HChaCha20 is also added so that
XChaCha20 can use it rather than the generic implementation.  This
required refactoring the ChaCha permutation into its own function.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Add a 64-bit AVX2 implementation of NHPoly1305, an ε-almost-∆-universal
hash function used in the Adiantum encryption mode.  For now, only the
NH portion is actually AVX2-accelerated; the Poly1305 part is less
performance-critical so is just implemented in C.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Add a 64-bit SSE2 implementation of NHPoly1305, an ε-almost-∆-universal
hash function used in the Adiantum encryption mode.  For now, only the
NH portion is actually SSE2-accelerated; the Poly1305 part is less
performance-critical so is just implemented in C.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

CRYPTO_STATS is using CRYPTO_USER stuff, so it should depends on it.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Add support for the Adiantum encryption mode.  Adiantum was designed by
Paul Crowley and is specified by our paper:

    Adiantum: length-preserving encryption for entry-level processors
    (https://eprint.iacr.org/2018/720.pdf)

See our paper for full details; this patch only provides an overview.

Adiantum is a tweakable, length-preserving encryption mode designed for
fast and secure disk encryption, especially on CPUs without dedicated
crypto instructions.  Adiantum encrypts each sector using the XChaCha12
stream cipher, two passes of an ε-almost-∆-universal (εA∆U) hash
function, and an invocation of the AES-256 block cipher on a single
16-byte block.  On CPUs without AES instructions, Adiantum is much
faster than AES-XTS; for example, on ARM Cortex-A7, on 4096-byte sectors
Adiantum encryption is about 4 times faster than AES-256-XTS encryption,
and decryption about 5 times faster.

Adiantum is a specialization of the more general HBSH construction.  Our
earlier proposal, HPolyC, was also a HBSH specialization, but it used a
different εA∆U hash function, one based on Poly1305 only.  Adiantum's
εA∆U hash function, which is based primarily on the "NH" hash function
like that used in UMAC (RFC4418), is about twice as fast as HPolyC's;
consequently, Adiantum is about 20% faster than HPolyC.

This speed comes with no loss of security: Adiantum is provably just as
secure as HPolyC, in fact slightly *more* secure.  Like HPolyC,
Adiantum's security is reducible to that of XChaCha12 and AES-256,
subject to a security bound.  XChaCha12 itself has a security reduction
to ChaCha12.  Therefore, one need not "trust" Adiantum; one need only
trust ChaCha12 and AES-256.  Note that the εA∆U hash function is only
used for its proven combinatorical properties so cannot be "broken".

Adiantum is also a true wide-block encryption mode, so flipping any
plaintext bit in the sector scrambles the entire ciphertext, and vice
versa.  No other such mode is available in the kernel currently; doing
the same with XTS scrambles only 16 bytes.  Adiantum also supports
arbitrary-length tweaks and naturally supports any length input >= 16
bytes without needing "ciphertext stealing".

For the stream cipher, Adiantum uses XChaCha12 rather than XChaCha20 in
order to make encryption feasible on the widest range of devices.
Although the 20-round variant is quite popular, the best known attacks
on ChaCha are on only 7 rounds, so ChaCha12 still has a substantial
security margin; in fact, larger than AES-256's.  12-round Salsa20 is
also the eSTREAM recommendation.  For the block cipher, Adiantum uses
AES-256, despite it having a lower security margin than XChaCha12 and
needing table lookups, due to AES's extensive adoption and analysis
making it the obvious first choice.  Nevertheless, for flexibility this
patch also permits the "adiantum" template to be instantiated with
XChaCha20 and/or with an alternate block cipher.

We need Adiantum support in the kernel for use in dm-crypt and fscrypt,
where currently the only other suitable options are block cipher modes
such as AES-XTS.  A big problem with this is that many low-end mobile
devices (e.g. Android Go phones sold primarily in developing countries,
as well as some smartwatches) still have CPUs that lack AES
instructions, e.g. ARM Cortex-A7.  Sadly, AES-XTS encryption is much too
slow to be viable on these devices.  We did find that some "lightweight"
block ciphers are fast enough, but these suffer from problems such as
not having much cryptanalysis or being too controversial.

The ChaCha stream cipher has excellent performance but is insecure to
use directly for disk encryption, since each sector's IV is reused each
time it is overwritten.  Even restricting the threat model to offline
attacks only isn't enough, since modern flash storage devices don't
guarantee that "overwrites" are really overwrites, due to wear-leveling.
Adiantum avoids this problem by constructing a
"tweakable super-pseudorandom permutation"; this is the strongest
possible security model for length-preserving encryption.

Of course, storing random nonces along with the ciphertext would be the
ideal solution.  But doing that with existing hardware and filesystems
runs into major practical problems; in most cases it would require data
journaling (like dm-integrity) which severely degrades performance.
Thus, for now length-preserving encryption is still needed.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>