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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 <crypto/speck.h>
+#include <linux/bitops.h>
+#include <linux/crypto.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+/* Speck128 */
+
+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);
+}
+
+void crypto_speck128_encrypt(const struct speck128_tfm_ctx *ctx,
+ u8 *out, const u8 *in)
+{
+ 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);
+}
+EXPORT_SYMBOL_GPL(crypto_speck128_encrypt);
+
+static void speck128_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+ crypto_speck128_encrypt(crypto_tfm_ctx(tfm), out, in);
+}
+
+void crypto_speck128_decrypt(const struct speck128_tfm_ctx *ctx,
+ u8 *out, const u8 *in)
+{
+ 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);
+}
+EXPORT_SYMBOL_GPL(crypto_speck128_decrypt);
+
+static void speck128_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+ crypto_speck128_decrypt(crypto_tfm_ctx(tfm), out, in);
+}
+
+int crypto_speck128_setkey(struct speck128_tfm_ctx *ctx, const u8 *key,
+ unsigned int keylen)
+{
+ 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;
+}
+EXPORT_SYMBOL_GPL(crypto_speck128_setkey);
+
+static int speck128_setkey(struct crypto_tfm *tfm, const u8 *key,
+ unsigned int keylen)
+{
+ return crypto_speck128_setkey(crypto_tfm_ctx(tfm), key, keylen);
+}
+
+/* Speck64 */
+
+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);
+}
+
+void crypto_speck64_encrypt(const struct speck64_tfm_ctx *ctx,
+ u8 *out, const u8 *in)
+{
+ 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);
+}
+EXPORT_SYMBOL_GPL(crypto_speck64_encrypt);
+
+static void speck64_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+ crypto_speck64_encrypt(crypto_tfm_ctx(tfm), out, in);
+}
+
+void crypto_speck64_decrypt(const struct speck64_tfm_ctx *ctx,
+ u8 *out, const u8 *in)
+{
+ 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);
+}
+EXPORT_SYMBOL_GPL(crypto_speck64_decrypt);
+
+static void speck64_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+{
+ crypto_speck64_decrypt(crypto_tfm_ctx(tfm), out, in);
+}
+
+int crypto_speck64_setkey(struct speck64_tfm_ctx *ctx, const u8 *key,
+ unsigned int keylen)
+{
+ 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;
+}
+EXPORT_SYMBOL_GPL(crypto_speck64_setkey);
+
+static int speck64_setkey(struct crypto_tfm *tfm, const u8 *key,
+ unsigned int keylen)
+{
+ return crypto_speck64_setkey(crypto_tfm_ctx(tfm), key, keylen);
+}
+
+/* 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");