Add support for POLYVAL, an ε-Δ-universal hash function similar to
GHASH. This patch adds POLYVAL to be used as a component to implement
HCTR2 mode. It should be noted that POLYVAL was originally specified
for use in AES-GCM-SIV (RFC 8452), but the kernel does not currently
support this mode.
POLYVAL is implemented as an shash algorithm. The implementation is
modified from ghash-generic.c.
For more information on POLYVAL see:
Length-preserving encryption with HCTR2:
https://eprint.iacr.org/2021/1441.pdf
AES-GCM-SIV: Nonce Misuse-Resistant Authenticated Encryption:
https://datatracker.ietf.org/doc/html/rfc8452
Signed-off-by: Nathan Huckleberry <[email protected]>
Reviewed-by: Eric Biggers <[email protected]>
---
crypto/Kconfig | 8 ++
crypto/Makefile | 1 +
crypto/polyval-generic.c | 214 +++++++++++++++++++++++++++++++++++++++
crypto/tcrypt.c | 4 +
crypto/testmgr.c | 6 ++
crypto/testmgr.h | 171 +++++++++++++++++++++++++++++++
include/crypto/polyval.h | 17 ++++
7 files changed, 421 insertions(+)
create mode 100644 crypto/polyval-generic.c
create mode 100644 include/crypto/polyval.h
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 47752aaa16ff..00139845d76d 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -768,6 +768,14 @@ config CRYPTO_GHASH
GHASH is the hash function used in GCM (Galois/Counter Mode).
It is not a general-purpose cryptographic hash function.
+config CRYPTO_POLYVAL
+ tristate
+ select CRYPTO_GF128MUL
+ select CRYPTO_HASH
+ help
+ POLYVAL is the hash function used in HCTR2. It is not a general-purpose
+ cryptographic hash function.
+
config CRYPTO_POLY1305
tristate "Poly1305 authenticator algorithm"
select CRYPTO_HASH
diff --git a/crypto/Makefile b/crypto/Makefile
index 6b3fe3df1489..561f901a91d4 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -169,6 +169,7 @@ UBSAN_SANITIZE_jitterentropy.o = n
jitterentropy_rng-y := jitterentropy.o jitterentropy-kcapi.o
obj-$(CONFIG_CRYPTO_TEST) += tcrypt.o
obj-$(CONFIG_CRYPTO_GHASH) += ghash-generic.o
+obj-$(CONFIG_CRYPTO_POLYVAL) += polyval-generic.o
obj-$(CONFIG_CRYPTO_USER_API) += af_alg.o
obj-$(CONFIG_CRYPTO_USER_API_HASH) += algif_hash.o
obj-$(CONFIG_CRYPTO_USER_API_SKCIPHER) += algif_skcipher.o
diff --git a/crypto/polyval-generic.c b/crypto/polyval-generic.c
new file mode 100644
index 000000000000..1399af125b93
--- /dev/null
+++ b/crypto/polyval-generic.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * POLYVAL: hash function for HCTR2.
+ *
+ * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <[email protected]>
+ * Copyright (c) 2009 Intel Corp.
+ * Author: Huang Ying <[email protected]>
+ * Copyright 2021 Google LLC
+ */
+
+/*
+ * Code based on crypto/ghash-generic.c
+ *
+ * POLYVAL is a keyed hash function similar to GHASH. POLYVAL uses a different
+ * modulus for finite field multiplication which makes hardware accelerated
+ * implementations on little-endian machines faster. POLYVAL is used in the
+ * kernel to implement HCTR2, but was originally specified for AES-GCM-SIV
+ * (RFC 8452).
+ *
+ * For more information see:
+ * Length-preserving encryption with HCTR2:
+ * https://eprint.iacr.org/2021/1441.pdf
+ * AES-GCM-SIV: Nonce Misuse-Resistant Authenticated Encryption:
+ * https://datatracker.ietf.org/doc/html/rfc8452
+ *
+ * Like GHASH, POLYVAL is not a cryptographic hash function and should
+ * not be used outside of crypto modes explicitly designed to use POLYVAL.
+ *
+ * This implementation uses a convenient trick involving the GHASH and POLYVAL
+ * fields. This trick allows multiplication in the POLYVAL field to be
+ * implemented by using multiplication in the GHASH field as a subroutine. An
+ * element of the POLYVAL field can be converted to an element of the GHASH
+ * field by computing x*REVERSE(a), where REVERSE reverses the byte-ordering of
+ * a. Similarly, an element of the GHASH field can be converted back to the
+ * POLYVAL field by computing REVERSE(x^{-1}*a). For more information, see:
+ * https://datatracker.ietf.org/doc/html/rfc8452#appendix-A
+ *
+ * By using this trick, we do not need to implement the POLYVAL field for the
+ * generic implementation.
+ *
+ * Warning: this generic implementation is not intended to be used in practice
+ * and is not constant time. For practical use, a hardware accelerated
+ * implementation of POLYVAL should be used instead.
+ *
+ */
+
+#include <asm/unaligned.h>
+#include <crypto/algapi.h>
+#include <crypto/gf128mul.h>
+#include <crypto/polyval.h>
+#include <crypto/internal/hash.h>
+#include <linux/crypto.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+struct polyval_tfm_ctx {
+ struct gf128mul_4k *gf128;
+};
+
+struct polyval_desc_ctx {
+ union {
+ u8 buffer[POLYVAL_BLOCK_SIZE];
+ be128 buffer128;
+ };
+ u32 bytes;
+};
+
+static int polyval_init(struct shash_desc *desc)
+{
+ struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
+
+ memset(dctx, 0, sizeof(*dctx));
+
+ return 0;
+}
+
+static void reverse_block(u8 block[POLYVAL_BLOCK_SIZE])
+{
+ u64 *p1 = (u64 *)block;
+ u64 *p2 = (u64 *)&block[8];
+ u64 a = get_unaligned(p1);
+ u64 b = get_unaligned(p2);
+
+ put_unaligned(swab64(a), p2);
+ put_unaligned(swab64(b), p1);
+}
+
+static int polyval_setkey(struct crypto_shash *tfm,
+ const u8 *key, unsigned int keylen)
+{
+ struct polyval_tfm_ctx *ctx = crypto_shash_ctx(tfm);
+ be128 k;
+
+ if (keylen != POLYVAL_BLOCK_SIZE)
+ return -EINVAL;
+
+ gf128mul_free_4k(ctx->gf128);
+
+ BUILD_BUG_ON(sizeof(k) != POLYVAL_BLOCK_SIZE);
+ // avoid violating alignment rules
+ memcpy(&k, key, POLYVAL_BLOCK_SIZE);
+
+ reverse_block((u8 *)&k);
+ gf128mul_x_lle(&k, &k);
+
+ ctx->gf128 = gf128mul_init_4k_lle(&k);
+ memzero_explicit(&k, POLYVAL_BLOCK_SIZE);
+
+ if (!ctx->gf128)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static int polyval_update(struct shash_desc *desc,
+ const u8 *src, unsigned int srclen)
+{
+ struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
+ const struct polyval_tfm_ctx *ctx = crypto_shash_ctx(desc->tfm);
+ u8 *pos;
+ u8 tmp[POLYVAL_BLOCK_SIZE];
+ int n;
+
+ if (dctx->bytes) {
+ n = min(srclen, dctx->bytes);
+ pos = dctx->buffer + dctx->bytes - 1;
+
+ dctx->bytes -= n;
+ srclen -= n;
+
+ while (n--)
+ *pos-- ^= *src++;
+
+ if (!dctx->bytes)
+ gf128mul_4k_lle(&dctx->buffer128, ctx->gf128);
+ }
+
+ while (srclen >= POLYVAL_BLOCK_SIZE) {
+ memcpy(tmp, src, POLYVAL_BLOCK_SIZE);
+ reverse_block(tmp);
+ crypto_xor(dctx->buffer, tmp, POLYVAL_BLOCK_SIZE);
+ gf128mul_4k_lle(&dctx->buffer128, ctx->gf128);
+ src += POLYVAL_BLOCK_SIZE;
+ srclen -= POLYVAL_BLOCK_SIZE;
+ }
+
+ if (srclen) {
+ dctx->bytes = POLYVAL_BLOCK_SIZE - srclen;
+ pos = dctx->buffer + POLYVAL_BLOCK_SIZE - 1;
+ while (srclen--)
+ *pos-- ^= *src++;
+ }
+
+ return 0;
+}
+
+static int polyval_final(struct shash_desc *desc, u8 *dst)
+{
+ struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
+ const struct polyval_tfm_ctx *ctx = crypto_shash_ctx(desc->tfm);
+
+ if (dctx->bytes)
+ gf128mul_4k_lle(&dctx->buffer128, ctx->gf128);
+ dctx->bytes = 0;
+
+ reverse_block(dctx->buffer);
+ memcpy(dst, dctx->buffer, POLYVAL_BLOCK_SIZE);
+
+ return 0;
+}
+
+static void polyval_exit_tfm(struct crypto_tfm *tfm)
+{
+ struct polyval_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ gf128mul_free_4k(ctx->gf128);
+}
+
+static struct shash_alg polyval_alg = {
+ .digestsize = POLYVAL_DIGEST_SIZE,
+ .init = polyval_init,
+ .update = polyval_update,
+ .final = polyval_final,
+ .setkey = polyval_setkey,
+ .descsize = sizeof(struct polyval_desc_ctx),
+ .base = {
+ .cra_name = "polyval",
+ .cra_driver_name = "polyval-generic",
+ .cra_priority = 100,
+ .cra_blocksize = POLYVAL_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct polyval_tfm_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_exit = polyval_exit_tfm,
+ },
+};
+
+static int __init polyval_mod_init(void)
+{
+ return crypto_register_shash(&polyval_alg);
+}
+
+static void __exit polyval_mod_exit(void)
+{
+ crypto_unregister_shash(&polyval_alg);
+}
+
+subsys_initcall(polyval_mod_init);
+module_exit(polyval_mod_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("POLYVAL hash function");
+MODULE_ALIAS_CRYPTO("polyval");
+MODULE_ALIAS_CRYPTO("polyval-generic");
diff --git a/crypto/tcrypt.c b/crypto/tcrypt.c
index fd671d0e2012..dd9cf216029b 100644
--- a/crypto/tcrypt.c
+++ b/crypto/tcrypt.c
@@ -1730,6 +1730,10 @@ static int do_test(const char *alg, u32 type, u32 mask, int m, u32 num_mb)
ret += tcrypt_test("ccm(sm4)");
break;
+ case 57:
+ ret += tcrypt_test("polyval");
+ break;
+
case 100:
ret += tcrypt_test("hmac(md5)");
break;
diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index fbb12d7d78af..d807b200edf6 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -5284,6 +5284,12 @@ static const struct alg_test_desc alg_test_descs[] = {
.suite = {
.hash = __VECS(poly1305_tv_template)
}
+ }, {
+ .alg = "polyval",
+ .test = alg_test_hash,
+ .suite = {
+ .hash = __VECS(polyval_tv_template)
+ }
}, {
.alg = "rfc3686(ctr(aes))",
.test = alg_test_skcipher,
diff --git a/crypto/testmgr.h b/crypto/testmgr.h
index bf4ff97eeb37..c581e5405916 100644
--- a/crypto/testmgr.h
+++ b/crypto/testmgr.h
@@ -34929,4 +34929,175 @@ static const struct cipher_testvec aes_xctr_tv_template[] = {
};
+/*
+ * Test vectors generated using https://github.com/google/hctr2
+ *
+ * To ensure compatibility with RFC 8452, some tests were sourced from
+ * https://datatracker.ietf.org/doc/html/rfc8452
+ */
+static const struct hash_testvec polyval_tv_template[] = {
+ { // From RFC 8452
+ .key = "\x31\x07\x28\xd9\x91\x1f\x1f\x38"
+ "\x37\xb2\x43\x16\xc3\xfa\xb9\xa0",
+ .plaintext = "\x65\x78\x61\x6d\x70\x6c\x65\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x48\x65\x6c\x6c\x6f\x20\x77\x6f"
+ "\x72\x6c\x64\x00\x00\x00\x00\x00"
+ "\x38\x00\x00\x00\x00\x00\x00\x00"
+ "\x58\x00\x00\x00\x00\x00\x00\x00",
+ .digest = "\xad\x7f\xcf\x0b\x51\x69\x85\x16"
+ "\x62\x67\x2f\x3c\x5f\x95\x13\x8f",
+ .psize = 48,
+ .ksize = 16,
+ },
+ { // From RFC 8452
+ .key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
+ "\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
+ .plaintext = "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00",
+ .digest = "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00",
+ .psize = 16,
+ .ksize = 16,
+ },
+ { // From RFC 8452
+ .key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
+ "\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
+ .plaintext = "\x01\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x40\x00\x00\x00\x00\x00\x00\x00",
+ .digest = "\xeb\x93\xb7\x74\x09\x62\xc5\xe4"
+ "\x9d\x2a\x90\xa7\xdc\x5c\xec\x74",
+ .psize = 32,
+ .ksize = 16,
+ },
+ { // From RFC 8452
+ .key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
+ "\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
+ .plaintext = "\x01\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x02\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x03\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x80\x01\x00\x00\x00\x00\x00\x00",
+ .digest = "\x81\x38\x87\x46\xbc\x22\xd2\x6b"
+ "\x2a\xbc\x3d\xcb\x15\x75\x42\x22",
+ .psize = 64,
+ .ksize = 16,
+ },
+ { // From RFC 8452
+ .key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
+ "\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
+ .plaintext = "\x01\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x02\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x03\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x04\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x02\x00\x00\x00\x00\x00\x00",
+ .digest = "\x1e\x39\xb6\xd3\x34\x4d\x34\x8f"
+ "\x60\x44\xf8\x99\x35\xd1\xcf\x78",
+ .psize = 80,
+ .ksize = 16,
+ },
+ { // From RFC 8452
+ .key = "\xd9\xb3\x60\x27\x96\x94\x94\x1a"
+ "\xc5\xdb\xc6\x98\x7a\xda\x73\x77",
+ .plaintext = "\x01\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x02\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x03\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x04\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x05\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x08\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x02\x00\x00\x00\x00\x00\x00",
+ .digest = "\xff\xcd\x05\xd5\x77\x0f\x34\xad"
+ "\x92\x67\xf0\xa5\x99\x94\xb1\x5a",
+ .psize = 96,
+ .ksize = 16,
+ },
+ { // Random ( 1)
+ .key = "\x90\xcc\xac\xee\xba\xd7\xd4\x68"
+ "\x98\xa6\x79\x70\xdf\x66\x15\x6c",
+ .plaintext = "",
+ .digest = "\x00\x00\x00\x00\x00\x00\x00\x00"
+ "\x00\x00\x00\x00\x00\x00\x00\x00",
+ .psize = 0,
+ .ksize = 16,
+ },
+ { // Random ( 1)
+ .key = "\xc1\x45\x71\xf0\x30\x07\x94\xe7"
+ "\x3a\xdd\xe4\xc6\x19\x2d\x02\xa2",
+ .plaintext = "\xc1\x5d\x47\xc7\x4c\x7c\x5e\x07"
+ "\x85\x14\x8f\x79\xcc\x73\x83\xf7"
+ "\x35\xb8\xcb\x73\x61\xf0\x53\x31"
+ "\xbf\x84\xde\xb6\xde\xaf\xb0\xb8"
+ "\xb7\xd9\x11\x91\x89\xfd\x1e\x4c"
+ "\x84\x4a\x1f\x2a\x87\xa4\xaf\x62"
+ "\x8d\x7d\x58\xf6\x43\x35\xfc\x53"
+ "\x8f\x1a\xf6\x12\xe1\x13\x3f\x66"
+ "\x91\x4b\x13\xd6\x45\xfb\xb0\x7a"
+ "\xe0\x8b\x8e\x99\xf7\x86\x46\x37"
+ "\xd1\x22\x9e\x52\xf3\x3f\xd9\x75"
+ "\x2c\x2c\xc6\xbb\x0e\x08\x14\x29"
+ "\xe8\x50\x2f\xd8\xbe\xf4\xe9\x69"
+ "\x4a\xee\xf7\xae\x15\x65\x35\x1e",
+ .digest = "\x00\x4f\x5d\xe9\x3b\xc0\xd6\x50"
+ "\x3e\x38\x73\x86\xc6\xda\xca\x7f",
+ .psize = 112,
+ .ksize = 16,
+ },
+ { // Random ( 1)
+ .key = "\x37\xbe\x68\x16\x50\xb9\x4e\xb0"
+ "\x47\xde\xe2\xbd\xde\xe4\x48\x09",
+ .plaintext = "\x87\xfc\x68\x9f\xff\xf2\x4a\x1e"
+ "\x82\x3b\x73\x8f\xc1\xb2\x1b\x7a"
+ "\x6c\x4f\x81\xbc\x88\x9b\x6c\xa3"
+ "\x9c\xc2\xa5\xbc\x14\x70\x4c\x9b"
+ "\x0c\x9f\x59\x92\x16\x4b\x91\x3d"
+ "\x18\x55\x22\x68\x12\x8c\x63\xb2"
+ "\x51\xcb\x85\x4b\xd2\xae\x0b\x1c"
+ "\x5d\x28\x9d\x1d\xb1\xc8\xf0\x77"
+ "\xe9\xb5\x07\x4e\x06\xc8\xee\xf8"
+ "\x1b\xed\x72\x2a\x55\x7d\x16\xc9"
+ "\xf2\x54\xe7\xe9\xe0\x44\x5b\x33"
+ "\xb1\x49\xee\xff\x43\xfb\x82\xcd"
+ "\x4a\x70\x78\x81\xa4\x34\x36\xe8"
+ "\x4c\x28\x54\xa6\x6c\xc3\x6b\x78"
+ "\xe7\xc0\x5d\xc6\x5d\x81\xab\x70"
+ "\x08\x86\xa1\xfd\xf4\x77\x55\xfd"
+ "\xa3\xe9\xe2\x1b\xdf\x99\xb7\x80"
+ "\xf9\x0a\x4f\x72\x4a\xd3\xaf\xbb"
+ "\xb3\x3b\xeb\x08\x58\x0f\x79\xce"
+ "\xa5\x99\x05\x12\x34\xd4\xf4\x86"
+ "\x37\x23\x1d\xc8\x49\xc0\x92\xae"
+ "\xa6\xac\x9b\x31\x55\xed\x15\xc6"
+ "\x05\x17\x37\x8d\x90\x42\xe4\x87"
+ "\x89\x62\x88\x69\x1c\x6a\xfd\xe3"
+ "\x00\x2b\x47\x1a\x73\xc1\x51\xc2"
+ "\xc0\x62\x74\x6a\x9e\xb2\xe5\x21"
+ "\xbe\x90\xb5\xb0\x50\xca\x88\x68"
+ "\xe1\x9d\x7a\xdf\x6c\xb7\xb9\x98"
+ "\xee\x28\x62\x61\x8b\xd1\x47\xf9"
+ "\x04\x7a\x0b\x5d\xcd\x2b\x65\xf5"
+ "\x12\xa3\xfe\x1a\xaa\x2c\x78\x42"
+ "\xb8\xbe\x7d\x74\xeb\x59\xba\xba",
+ .digest = "\xae\x11\xd4\x60\x2a\x5f\x9e\x42"
+ "\x89\x04\xc2\x34\x8d\x55\x94\x0a",
+ .psize = 256,
+ .ksize = 16,
+ },
+
+};
+
#endif /* _CRYPTO_TESTMGR_H */
diff --git a/include/crypto/polyval.h b/include/crypto/polyval.h
new file mode 100644
index 000000000000..b14c38aa9166
--- /dev/null
+++ b/include/crypto/polyval.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common values for the Polyval hash algorithm
+ *
+ * Copyright 2021 Google LLC
+ */
+
+#ifndef _CRYPTO_POLYVAL_H
+#define _CRYPTO_POLYVAL_H
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+
+#define POLYVAL_BLOCK_SIZE 16
+#define POLYVAL_DIGEST_SIZE 16
+
+#endif
--
2.35.1.1178.g4f1659d476-goog
A couple more nits:
On Tue, Apr 12, 2022 at 05:28:10PM +0000, Nathan Huckleberry wrote:
> +static int polyval_init(struct shash_desc *desc)
[...]
> +static int polyval_setkey(struct crypto_shash *tfm,
As I mentioned on the x86 patch, setkey() is the first step, before init().
People sometimes mix this up, e.g. see https://git.kernel.org/linus/f3aefb6a7066e24b.
Putting the definitions in their natural order might be helpful:
1. polyval_setkey()
2. polyval_init()
3. polyval_update()
4. polyval_final()
> +static void reverse_block(u8 block[POLYVAL_BLOCK_SIZE])
> +{
> + u64 *p1 = (u64 *)block;
> + u64 *p2 = (u64 *)&block[8];
> + u64 a = get_unaligned(p1);
> + u64 b = get_unaligned(p2);
> +
> + put_unaligned(swab64(a), p2);
> + put_unaligned(swab64(b), p1);
> +}
This is always paired with a memcpy() of the block, so consider making this
helper function handle the copy too. E.g.
diff --git a/crypto/polyval-generic.c b/crypto/polyval-generic.c
index 1399af125b937..b50db5dd51fd1 100644
--- a/crypto/polyval-generic.c
+++ b/crypto/polyval-generic.c
@@ -75,15 +75,14 @@ static int polyval_init(struct shash_desc *desc)
return 0;
}
-static void reverse_block(u8 block[POLYVAL_BLOCK_SIZE])
+static void copy_and_reverse(u8 dst[POLYVAL_BLOCK_SIZE],
+ const u8 src[POLYVAL_BLOCK_SIZE])
{
- u64 *p1 = (u64 *)block;
- u64 *p2 = (u64 *)&block[8];
- u64 a = get_unaligned(p1);
- u64 b = get_unaligned(p2);
+ u64 a = get_unaligned((const u64 *)&src[0]);
+ u64 b = get_unaligned((const u64 *)&src[8]);
- put_unaligned(swab64(a), p2);
- put_unaligned(swab64(b), p1);
+ put_unaligned(swab64(a), (u64 *)&dst[8]);
+ put_unaligned(swab64(b), (u64 *)&dst[0]);
}
static int polyval_setkey(struct crypto_shash *tfm,
@@ -98,10 +97,7 @@ static int polyval_setkey(struct crypto_shash *tfm,
gf128mul_free_4k(ctx->gf128);
BUILD_BUG_ON(sizeof(k) != POLYVAL_BLOCK_SIZE);
- // avoid violating alignment rules
- memcpy(&k, key, POLYVAL_BLOCK_SIZE);
-
- reverse_block((u8 *)&k);
+ copy_and_reverse((u8 *)&k, key);
gf128mul_x_lle(&k, &k);
ctx->gf128 = gf128mul_init_4k_lle(&k);
@@ -137,8 +133,7 @@ static int polyval_update(struct shash_desc *desc,
}
while (srclen >= POLYVAL_BLOCK_SIZE) {
- memcpy(tmp, src, POLYVAL_BLOCK_SIZE);
- reverse_block(tmp);
+ copy_and_reverse(tmp, src);
crypto_xor(dctx->buffer, tmp, POLYVAL_BLOCK_SIZE);
gf128mul_4k_lle(&dctx->buffer128, ctx->gf128);
src += POLYVAL_BLOCK_SIZE;
@@ -162,11 +157,7 @@ static int polyval_final(struct shash_desc *desc, u8 *dst)
if (dctx->bytes)
gf128mul_4k_lle(&dctx->buffer128, ctx->gf128);
- dctx->bytes = 0;
-
- reverse_block(dctx->buffer);
- memcpy(dst, dctx->buffer, POLYVAL_BLOCK_SIZE);
-
+ copy_and_reverse(dst, dctx->buffer);
return 0;
}