crypto: blake2s - generic C library implementation and selftest

The C implementation was originally based on Samuel Neves' public
domain reference implementation but has since been heavily modified
for the kernel. We're able to do compile-time optimizations by moving
some scaffolding around the final function into the header file.

Information: https://blake2.net/

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Samuel Neves <sneves@dei.uc.pt>
Co-developed-by: Samuel Neves <sneves@dei.uc.pt>
[ardb: - move from lib/zinc to lib/crypto
       - remove simd handling
       - rewrote selftest for better coverage
       - use fixed digest length for blake2s_hmac() and rename to
         blake2s256_hmac() ]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 126 insertions, 0 deletions

diff --git a/lib/crypto/blake2s.c b/lib/crypto/blake2s.c
new file mode 100644
index 000000000000..41025a30c524
--- /dev/null
+++ b/lib/crypto/blake2s.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This is an implementation of the BLAKE2s hash and PRF functions.
+ *
+ * Information: https://blake2.net/
+ *
+ */
+
+#include <crypto/internal/blake2s.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bug.h>
+#include <asm/unaligned.h>
+
+bool blake2s_selftest(void);
+
+void blake2s_update(struct blake2s_state *state, const u8 *in, size_t inlen)
+{
+	const size_t fill = BLAKE2S_BLOCK_SIZE - state->buflen;
+
+	if (unlikely(!inlen))
+		return;
+	if (inlen > fill) {
+		memcpy(state->buf + state->buflen, in, fill);
+		if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_BLAKE2S))
+			blake2s_compress_arch(state, state->buf, 1,
+					      BLAKE2S_BLOCK_SIZE);
+		else
+			blake2s_compress_generic(state, state->buf, 1,
+						 BLAKE2S_BLOCK_SIZE);
+		state->buflen = 0;
+		in += fill;
+		inlen -= fill;
+	}
+	if (inlen > BLAKE2S_BLOCK_SIZE) {
+		const size_t nblocks = DIV_ROUND_UP(inlen, BLAKE2S_BLOCK_SIZE);
+		/* Hash one less (full) block than strictly possible */
+		if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_BLAKE2S))
+			blake2s_compress_arch(state, in, nblocks - 1,
+					      BLAKE2S_BLOCK_SIZE);
+		else
+			blake2s_compress_generic(state, in, nblocks - 1,
+						 BLAKE2S_BLOCK_SIZE);
+		in += BLAKE2S_BLOCK_SIZE * (nblocks - 1);
+		inlen -= BLAKE2S_BLOCK_SIZE * (nblocks - 1);
+	}
+	memcpy(state->buf + state->buflen, in, inlen);
+	state->buflen += inlen;
+}
+EXPORT_SYMBOL(blake2s_update);
+
+void blake2s_final(struct blake2s_state *state, u8 *out)
+{
+	WARN_ON(IS_ENABLED(DEBUG) && !out);
+	blake2s_set_lastblock(state);
+	memset(state->buf + state->buflen, 0,
+	       BLAKE2S_BLOCK_SIZE - state->buflen); /* Padding */
+	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_BLAKE2S))
+		blake2s_compress_arch(state, state->buf, 1, state->buflen);
+	else
+		blake2s_compress_generic(state, state->buf, 1, state->buflen);
+	cpu_to_le32_array(state->h, ARRAY_SIZE(state->h));
+	memcpy(out, state->h, state->outlen);
+	memzero_explicit(state, sizeof(*state));
+}
+EXPORT_SYMBOL(blake2s_final);
+
+void blake2s256_hmac(u8 *out, const u8 *in, const u8 *key, const size_t inlen,
+		     const size_t keylen)
+{
+	struct blake2s_state state;
+	u8 x_key[BLAKE2S_BLOCK_SIZE] __aligned(__alignof__(u32)) = { 0 };
+	u8 i_hash[BLAKE2S_HASH_SIZE] __aligned(__alignof__(u32));
+	int i;
+
+	if (keylen > BLAKE2S_BLOCK_SIZE) {
+		blake2s_init(&state, BLAKE2S_HASH_SIZE);
+		blake2s_update(&state, key, keylen);
+		blake2s_final(&state, x_key);
+	} else
+		memcpy(x_key, key, keylen);
+
+	for (i = 0; i < BLAKE2S_BLOCK_SIZE; ++i)
+		x_key[i] ^= 0x36;
+
+	blake2s_init(&state, BLAKE2S_HASH_SIZE);
+	blake2s_update(&state, x_key, BLAKE2S_BLOCK_SIZE);
+	blake2s_update(&state, in, inlen);
+	blake2s_final(&state, i_hash);
+
+	for (i = 0; i < BLAKE2S_BLOCK_SIZE; ++i)
+		x_key[i] ^= 0x5c ^ 0x36;
+
+	blake2s_init(&state, BLAKE2S_HASH_SIZE);
+	blake2s_update(&state, x_key, BLAKE2S_BLOCK_SIZE);
+	blake2s_update(&state, i_hash, BLAKE2S_HASH_SIZE);
+	blake2s_final(&state, i_hash);
+
+	memcpy(out, i_hash, BLAKE2S_HASH_SIZE);
+	memzero_explicit(x_key, BLAKE2S_BLOCK_SIZE);
+	memzero_explicit(i_hash, BLAKE2S_HASH_SIZE);
+}
+EXPORT_SYMBOL(blake2s256_hmac);
+
+static int __init mod_init(void)
+{
+	if (!IS_ENABLED(CONFIG_CRYPTO_MANAGER_DISABLE_TESTS) &&
+	    WARN_ON(!blake2s_selftest()))
+		return -ENODEV;
+	return 0;
+}
+
+static void __exit mod_exit(void)
+{
+}
+
+module_init(mod_init);
+module_exit(mod_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("BLAKE2s hash function");
+MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");