1 files changed, 299 insertions, 0 deletions
diff --git a/crypto/speck.c b/crypto/speck.c
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+++ b/crypto/speck.c
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Speck: a lightweight block cipher
+ *
+ * Copyright (c) 2018 Google, Inc
+ *
+ * Speck has 10 variants, including 5 block sizes.  For now we only implement
+ * the variants Speck128/128, Speck128/192, Speck128/256, Speck64/96, and
+ * Speck64/128.   Speck${B}/${K} denotes the variant with a block size of B bits
+ * and a key size of K bits.  The Speck128 variants are believed to be the most
+ * secure variants, and they use the same block size and key sizes as AES.  The
+ * Speck64 variants are less secure, but on 32-bit processors are usually
+ * faster.  The remaining variants (Speck32, Speck48, and Speck96) are even less
+ * secure and/or not as well suited for implementation on either 32-bit or
+ * 64-bit processors, so are omitted.
+ *
+ * Reference: "The Simon and Speck Families of Lightweight Block Ciphers"
+ * https://eprint.iacr.org/2013/404.pdf
+ *
+ * In a correspondence, the Speck designers have also clarified that the words
+ * should be interpreted in little-endian format, and the words should be
+ * ordered such that the first word of each block is 'y' rather than 'x', and
+ * the first key word (rather than the last) becomes the first round key.
+ */
+
+#include <asm/unaligned.h>
+#include <linux/bitops.h>
+#include <linux/crypto.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+/* Speck128 */
+
+#define SPECK128_BLOCK_SIZE	16
+
+#define SPECK128_128_KEY_SIZE	16
+#define SPECK128_128_NROUNDS	32
+
+#define SPECK128_192_KEY_SIZE	24
+#define SPECK128_192_NROUNDS	33
+
+#define SPECK128_256_KEY_SIZE	32
+#define SPECK128_256_NROUNDS	34
+
+struct speck128_tfm_ctx {
+	u64 round_keys[SPECK128_256_NROUNDS];
+	int nrounds;
+};
+
+static __always_inline void speck128_round(u64 *x, u64 *y, u64 k)
+{
+	*x = ror64(*x, 8);
+	*x += *y;
+	*x ^= k;
+	*y = rol64(*y, 3);
+	*y ^= *x;
+}
+
+static __always_inline void speck128_unround(u64 *x, u64 *y, u64 k)
+{
+	*y ^= *x;
+	*y = ror64(*y, 3);
+	*x ^= k;
+	*x -= *y;
+	*x = rol64(*x, 8);
+}
+
+static void speck128_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct speck128_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
+	u64 y = get_unaligned_le64(in);
+	u64 x = get_unaligned_le64(in + 8);
+	int i;
+
+	for (i = 0; i < ctx->nrounds; i++)
+		speck128_round(&x, &y, ctx->round_keys[i]);
+
+	put_unaligned_le64(y, out);
+	put_unaligned_le64(x, out + 8);
+}
+
+static void speck128_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct speck128_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
+	u64 y = get_unaligned_le64(in);
+	u64 x = get_unaligned_le64(in + 8);
+	int i;
+
+	for (i = ctx->nrounds - 1; i >= 0; i--)
+		speck128_unround(&x, &y, ctx->round_keys[i]);
+
+	put_unaligned_le64(y, out);
+	put_unaligned_le64(x, out + 8);
+}
+
+static int speck128_setkey(struct crypto_tfm *tfm, const u8 *key,
+			   unsigned int keylen)
+{
+	struct speck128_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
+	u64 l[3];
+	u64 k;
+	int i;
+
+	switch (keylen) {
+	case SPECK128_128_KEY_SIZE:
+		k = get_unaligned_le64(key);
+		l[0] = get_unaligned_le64(key + 8);
+		ctx->nrounds = SPECK128_128_NROUNDS;
+		for (i = 0; i < ctx->nrounds; i++) {
+			ctx->round_keys[i] = k;
+			speck128_round(&l[0], &k, i);
+		}
+		break;
+	case SPECK128_192_KEY_SIZE:
+		k = get_unaligned_le64(key);
+		l[0] = get_unaligned_le64(key + 8);
+		l[1] = get_unaligned_le64(key + 16);
+		ctx->nrounds = SPECK128_192_NROUNDS;
+		for (i = 0; i < ctx->nrounds; i++) {
+			ctx->round_keys[i] = k;
+			speck128_round(&l[i % 2], &k, i);
+		}
+		break;
+	case SPECK128_256_KEY_SIZE:
+		k = get_unaligned_le64(key);
+		l[0] = get_unaligned_le64(key + 8);
+		l[1] = get_unaligned_le64(key + 16);
+		l[2] = get_unaligned_le64(key + 24);
+		ctx->nrounds = SPECK128_256_NROUNDS;
+		for (i = 0; i < ctx->nrounds; i++) {
+			ctx->round_keys[i] = k;
+			speck128_round(&l[i % 3], &k, i);
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Speck64 */
+
+#define SPECK64_BLOCK_SIZE	8
+
+#define SPECK64_96_KEY_SIZE	12
+#define SPECK64_96_NROUNDS	26
+
+#define SPECK64_128_KEY_SIZE	16
+#define SPECK64_128_NROUNDS	27
+
+struct speck64_tfm_ctx {
+	u32 round_keys[SPECK64_128_NROUNDS];
+	int nrounds;
+};
+
+static __always_inline void speck64_round(u32 *x, u32 *y, u32 k)
+{
+	*x = ror32(*x, 8);
+	*x += *y;
+	*x ^= k;
+	*y = rol32(*y, 3);
+	*y ^= *x;
+}
+
+static __always_inline void speck64_unround(u32 *x, u32 *y, u32 k)
+{
+	*y ^= *x;
+	*y = ror32(*y, 3);
+	*x ^= k;
+	*x -= *y;
+	*x = rol32(*x, 8);
+}
+
+static void speck64_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct speck64_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
+	u32 y = get_unaligned_le32(in);
+	u32 x = get_unaligned_le32(in + 4);
+	int i;
+
+	for (i = 0; i < ctx->nrounds; i++)
+		speck64_round(&x, &y, ctx->round_keys[i]);
+
+	put_unaligned_le32(y, out);
+	put_unaligned_le32(x, out + 4);
+}
+
+static void speck64_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+	const struct speck64_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
+	u32 y = get_unaligned_le32(in);
+	u32 x = get_unaligned_le32(in + 4);
+	int i;
+
+	for (i = ctx->nrounds - 1; i >= 0; i--)
+		speck64_unround(&x, &y, ctx->round_keys[i]);
+
+	put_unaligned_le32(y, out);
+	put_unaligned_le32(x, out + 4);
+}
+
+static int speck64_setkey(struct crypto_tfm *tfm, const u8 *key,
+			  unsigned int keylen)
+{
+	struct speck64_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
+	u32 l[3];
+	u32 k;
+	int i;
+
+	switch (keylen) {
+	case SPECK64_96_KEY_SIZE:
+		k = get_unaligned_le32(key);
+		l[0] = get_unaligned_le32(key + 4);
+		l[1] = get_unaligned_le32(key + 8);
+		ctx->nrounds = SPECK64_96_NROUNDS;
+		for (i = 0; i < ctx->nrounds; i++) {
+			ctx->round_keys[i] = k;
+			speck64_round(&l[i % 2], &k, i);
+		}
+		break;
+	case SPECK64_128_KEY_SIZE:
+		k = get_unaligned_le32(key);
+		l[0] = get_unaligned_le32(key + 4);
+		l[1] = get_unaligned_le32(key + 8);
+		l[2] = get_unaligned_le32(key + 12);
+		ctx->nrounds = SPECK64_128_NROUNDS;
+		for (i = 0; i < ctx->nrounds; i++) {
+			ctx->round_keys[i] = k;
+			speck64_round(&l[i % 3], &k, i);
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Algorithm definitions */
+
+static struct crypto_alg speck_algs[] = {
+	{
+		.cra_name		= "speck128",
+		.cra_driver_name	= "speck128-generic",
+		.cra_priority		= 100,
+		.cra_flags		= CRYPTO_ALG_TYPE_CIPHER,
+		.cra_blocksize		= SPECK128_BLOCK_SIZE,
+		.cra_ctxsize		= sizeof(struct speck128_tfm_ctx),
+		.cra_module		= THIS_MODULE,
+		.cra_u			= {
+			.cipher = {
+				.cia_min_keysize	= SPECK128_128_KEY_SIZE,
+				.cia_max_keysize	= SPECK128_256_KEY_SIZE,
+				.cia_setkey		= speck128_setkey,
+				.cia_encrypt		= speck128_encrypt,
+				.cia_decrypt		= speck128_decrypt
+			}
+		}
+	}, {
+		.cra_name		= "speck64",
+		.cra_driver_name	= "speck64-generic",
+		.cra_priority		= 100,
+		.cra_flags		= CRYPTO_ALG_TYPE_CIPHER,
+		.cra_blocksize		= SPECK64_BLOCK_SIZE,
+		.cra_ctxsize		= sizeof(struct speck64_tfm_ctx),
+		.cra_module		= THIS_MODULE,
+		.cra_u			= {
+			.cipher = {
+				.cia_min_keysize	= SPECK64_96_KEY_SIZE,
+				.cia_max_keysize	= SPECK64_128_KEY_SIZE,
+				.cia_setkey		= speck64_setkey,
+				.cia_encrypt		= speck64_encrypt,
+				.cia_decrypt		= speck64_decrypt
+			}
+		}
+	}
+};
+
+static int __init speck_module_init(void)
+{
+	return crypto_register_algs(speck_algs, ARRAY_SIZE(speck_algs));
+}
+
+static void __exit speck_module_exit(void)
+{
+	crypto_unregister_algs(speck_algs, ARRAY_SIZE(speck_algs));
+}
+
+module_init(speck_module_init);
+module_exit(speck_module_exit);
+
+MODULE_DESCRIPTION("Speck block cipher (generic)");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Eric Biggers <ebiggers@google.com>");
+MODULE_ALIAS_CRYPTO("speck128");
+MODULE_ALIAS_CRYPTO("speck128-generic");
+MODULE_ALIAS_CRYPTO("speck64");
+MODULE_ALIAS_CRYPTO("speck64-generic");