commit e1354400b25da645c4764ed6844d12f1582c3b66 upstream.

The "hmac(sha3-224-generic)" algorithm has a descsize of 368 bytes,
which is greater than HASH_MAX_DESCSIZE (360) which is only enough for
sha3-224-generic.  The check in shash_prepare_alg() doesn't catch this
because the HMAC template doesn't set descsize on the algorithms, but
rather sets it on each individual HMAC transform.

This causes a stack buffer overflow when SHASH_DESC_ON_STACK() is used
with hmac(sha3-224-generic).

Fix it by increasing HASH_MAX_DESCSIZE to the real maximum.  Also add a
sanity check to hmac_init().

This was detected by the improved crypto self-tests in v5.2, by loading
the tcrypt module with CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y enabled.  I
didn't notice this bug when I ran the self-tests by requesting the
algorithms via AF_ALG (i.e., not using tcrypt), probably because the
stack layout differs in the two cases and that made a difference here.

KASAN report:

    BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:359 [inline]
    BUG: KASAN: stack-out-of-bounds in shash_default_import+0x52/0x80 crypto/shash.c:223
    Write of size 360 at addr ffff8880651defc8 by task insmod/3689

    CPU: 2 PID: 3689 Comm: insmod Tainted: G            E     5.1.0-10741-g35c99ffa20edd #11
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
    Call Trace:
     __dump_stack lib/dump_stack.c:77 [inline]
     dump_stack+0x86/0xc5 lib/dump_stack.c:113
     print_address_description+0x7f/0x260 mm/kasan/report.c:188
     __kasan_report+0x144/0x187 mm/kasan/report.c:317
     kasan_report+0x12/0x20 mm/kasan/common.c:614
     check_memory_region_inline mm/kasan/generic.c:185 [inline]
     check_memory_region+0x137/0x190 mm/kasan/generic.c:191
     memcpy+0x37/0x50 mm/kasan/common.c:125
     memcpy include/linux/string.h:359 [inline]
     shash_default_import+0x52/0x80 crypto/shash.c:223
     crypto_shash_import include/crypto/hash.h:880 [inline]
     hmac_import+0x184/0x240 crypto/hmac.c:102
     hmac_init+0x96/0xc0 crypto/hmac.c:107
     crypto_shash_init include/crypto/hash.h:902 [inline]
     shash_digest_unaligned+0x9f/0xf0 crypto/shash.c:194
     crypto_shash_digest+0xe9/0x1b0 crypto/shash.c:211
     generate_random_hash_testvec.constprop.11+0x1ec/0x5b0 crypto/testmgr.c:1331
     test_hash_vs_generic_impl+0x3f7/0x5c0 crypto/testmgr.c:1420
     __alg_test_hash+0x26d/0x340 crypto/testmgr.c:1502
     alg_test_hash+0x22e/0x330 crypto/testmgr.c:1552
     alg_test.part.7+0x132/0x610 crypto/testmgr.c:4931
     alg_test+0x1f/0x40 crypto/testmgr.c:4952

Fixes: b68a7ec1e9a3 ("crypto: hash - Remove VLA usage")
Reported-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Cc: <stable@vger.kernel.org> # v4.20+
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove dead code related to internal IV generators, which are no longer
used since they've been replaced with the "seqiv" and "echainiv"
templates.  The removed code includes:

- The "givcipher" (GIVCIPHER) algorithm type.  No algorithms are
  registered with this type anymore, so it's unneeded.

- The "const char *geniv" member of aead_alg, ablkcipher_alg, and
  blkcipher_alg.  A few algorithms still set this, but it isn't used
  anymore except to show via /proc/crypto and CRYPTO_MSG_GETALG.
  Just hardcode "<default>" or "<none>" in those cases.

- The 'skcipher_givcrypt_request' structure, which is never used.

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

This patch removes unused dump functions for crypto_user_stats.
There are remains of the copy/paste of crypto_user_base to
crypto_user_stat and I forgot to remove them.

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

All crypto_stats functions use the struct xxx_request for feeding stats,
but in some case this structure could already be freed.

For fixing this, the needed parameters (len and alg) will be stored
before the request being executed.
Fixes: cac5818c25d0 ("crypto: user - Implement a generic crypto statistics")
Reported-by: syzbot <syzbot+6939a606a5305e9e9799@syzkaller.appspotmail.com>

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

All the 32-bit fields need to be 64-bit.  In some cases, UINT32_MAX crypto
operations can be done in seconds.

Reported-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Even if CRYPTO_STATS is set to n, some part of CRYPTO_STATS are
compiled.
This patch made all part of crypto_user_stat uncompiled in that case.

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Add a generic implementation of NHPoly1305, an ε-almost-∆-universal hash
function used in the Adiantum encryption mode.

CONFIG_NHPOLY1305 is not selectable by itself since there won't be any
real reason to enable it without also enabling Adiantum support.

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

Expose a low-level Poly1305 API which implements the
ε-almost-∆-universal (εA∆U) hash function underlying the Poly1305 MAC
and supports block-aligned inputs only.

This is needed for Adiantum hashing, which builds an εA∆U hash function
from NH and a polynomial evaluation in GF(2^{130}-5); this polynomial
evaluation is identical to the one the Poly1305 MAC does.  However, the
crypto_shash Poly1305 API isn't very appropriate for this because its
calling convention assumes it is used as a MAC, with a 32-byte "one-time
key" provided for every digest.

But by design, in Adiantum hashing the performance of the polynomial
evaluation isn't nearly as critical as NH.  So it suffices to just have
some C helper functions.  Thus, this patch adds such functions.

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

In preparation for exposing a low-level Poly1305 API which implements
the ε-almost-∆-universal (εA∆U) hash function underlying the Poly1305
MAC and supports block-aligned inputs only, create structures
poly1305_key and poly1305_state which hold the limbs of the Poly1305
"r" key and accumulator, respectively.

These structures could actually have the same type (e.g. poly1305_val),
but different types are preferable, to prevent misuse.

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

Now that the generic implementation of ChaCha20 has been refactored to
allow varying the number of rounds, add support for XChaCha12, which is
the XSalsa construction applied to ChaCha12.  ChaCha12 is one of the
three ciphers specified by the original ChaCha paper
(https://cr.yp.to/chacha/chacha-20080128.pdf: "ChaCha, a variant of
Salsa20"), alongside ChaCha8 and ChaCha20.  ChaCha12 is faster than
ChaCha20 but has a lower, but still large, security margin.

We need XChaCha12 support so that it can be used in the Adiantum
encryption mode, which enables disk/file encryption on low-end mobile
devices where AES-XTS is too slow as the CPUs lack AES instructions.

We'd prefer XChaCha20 (the more popular variant), but it's too slow on
some of our target devices, so at least in some cases we do need the
XChaCha12-based version.  In more detail, the problem is that Adiantum
is still much slower than we're happy with, and encryption still has a
quite noticeable effect on the feel of low-end devices.  Users and
vendors push back hard against encryption that degrades the user
experience, which always risks encryption being disabled entirely.  So
we need to choose the fastest option that gives us a solid margin of
security, and here that's XChaCha12.  The best known attack on ChaCha
breaks only 7 rounds and has 2^235 time complexity, so ChaCha12's
security margin is still better than AES-256's.  Much has been learned
about cryptanalysis of ARX ciphers since Salsa20 was originally designed
in 2005, and it now seems we can be comfortable with a smaller number of
rounds.  The eSTREAM project also suggests the 12-round version of
Salsa20 as providing the best balance among the different variants:
combining very good performance with a "comfortable margin of security".

Note that it would be trivial to add vanilla ChaCha12 in addition to
XChaCha12.  However, it's unneeded for now and therefore is omitted.

As discussed in the patch that introduced XChaCha20 support, I
considered splitting the code into separate chacha-common, chacha20,
xchacha20, and xchacha12 modules, so that these algorithms could be
enabled/disabled independently.  However, since nearly all the code is
shared anyway, I ultimately decided there would have been little benefit
to the added complexity.

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