// SPDX-License-Identifier: GPL-2.0 /* * NEON-accelerated implementation of Speck128-XTS and Speck64-XTS * * Copyright (c) 2018 Google, Inc * * Note: the NIST recommendation for XTS only specifies a 128-bit block size, * but a 64-bit version (needed for Speck64) is fairly straightforward; the math * is just done in GF(2^64) instead of GF(2^128), with the reducing polynomial * x^64 + x^4 + x^3 + x + 1 from the original XEX paper (Rogaway, 2004: * "Efficient Instantiations of Tweakable Blockciphers and Refinements to Modes * OCB and PMAC"), represented as 0x1B. */ #include #include #include #include #include #include #include #include #include #include /* The assembly functions only handle multiples of 128 bytes */ #define SPECK_NEON_CHUNK_SIZE 128 /* Speck128 */ struct speck128_xts_tfm_ctx { struct speck128_tfm_ctx main_key; struct speck128_tfm_ctx tweak_key; }; asmlinkage void speck128_xts_encrypt_neon(const u64 *round_keys, int nrounds, void *dst, const void *src, unsigned int nbytes, void *tweak); asmlinkage void speck128_xts_decrypt_neon(const u64 *round_keys, int nrounds, void *dst, const void *src, unsigned int nbytes, void *tweak); typedef void (*speck128_crypt_one_t)(const struct speck128_tfm_ctx *, u8 *, const u8 *); typedef void (*speck128_xts_crypt_many_t)(const u64 *, int, void *, const void *, unsigned int, void *); static __always_inline int __speck128_xts_crypt(struct skcipher_request *req, speck128_crypt_one_t crypt_one, speck128_xts_crypt_many_t crypt_many) { struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); const struct speck128_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm); struct skcipher_walk walk; le128 tweak; int err; err = skcipher_walk_virt(&walk, req, true); crypto_speck128_encrypt(&ctx->tweak_key, (u8 *)&tweak, walk.iv); while (walk.nbytes > 0) { unsigned int nbytes = walk.nbytes; u8 *dst = walk.dst.virt.addr; const u8 *src = walk.src.virt.addr; if (nbytes >= SPECK_NEON_CHUNK_SIZE && may_use_simd()) { unsigned int count; count = round_down(nbytes, SPECK_NEON_CHUNK_SIZE); kernel_neon_begin(); (*crypt_many)(ctx->main_key.round_keys, ctx->main_key.nrounds, dst, src, count, &tweak); kernel_neon_end(); dst += count; src += count; nbytes -= count; } /* Handle any remainder with generic code */ while (nbytes >= sizeof(tweak)) { le128_xor((le128 *)dst, (const le128 *)src, &tweak); (*crypt_one)(&ctx->main_key, dst, dst); le128_xor((le128 *)dst, (const le128 *)dst, &tweak); gf128mul_x_ble(&tweak, &tweak); dst += sizeof(tweak); src += sizeof(tweak); nbytes -= sizeof(tweak); } err = skcipher_walk_done(&walk, nbytes); } return err; } static int speck128_xts_encrypt(struct skcipher_request *req) { return __speck128_xts_crypt(req, crypto_speck128_encrypt, speck128_xts_encrypt_neon); } static int speck128_xts_decrypt(struct skcipher_request *req) { return __speck128_xts_crypt(req, crypto_speck128_decrypt, speck128_xts_decrypt_neon); } static int speck128_xts_setkey(struct crypto_skcipher *tfm, const u8 *key, unsigned int keylen) { struct speck128_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm); int err; err = xts_verify_key(tfm, key, keylen); if (err) return err; keylen /= 2; err = crypto_speck128_setkey(&ctx->main_key, key, keylen); if (err) return err; return crypto_speck128_setkey(&ctx->tweak_key, key + keylen, keylen); } /* Speck64 */ struct speck64_xts_tfm_ctx { struct speck64_tfm_ctx main_key; struct speck64_tfm_ctx tweak_key; }; asmlinkage void speck64_xts_encrypt_neon(const u32 *round_keys, int nrounds, void *dst, const void *src, unsigned int nbytes, void *tweak); asmlinkage void speck64_xts_decrypt_neon(const u32 *round_keys, int nrounds, void *dst, const void *src, unsigned int nbytes, void *tweak); typedef void (*speck64_crypt_one_t)(const struct speck64_tfm_ctx *, u8 *, const u8 *); typedef void (*speck64_xts_crypt_many_t)(const u32 *, int, void *, const void *, unsigned int, void *); static __always_inline int __speck64_xts_crypt(struct skcipher_request *req, speck64_crypt_one_t crypt_one, speck64_xts_crypt_many_t crypt_many) { struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); const struct speck64_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm); struct skcipher_walk walk; __le64 tweak; int err; err = skcipher_walk_virt(&walk, req, true); crypto_speck64_encrypt(&ctx->tweak_key, (u8 *)&tweak, walk.iv); while (walk.nbytes > 0) { unsigned int nbytes = walk.nbytes; u8 *dst = walk.dst.virt.addr; const u8 *src = walk.src.virt.addr; if (nbytes >= SPECK_NEON_CHUNK_SIZE && may_use_simd()) { unsigned int count; count = round_down(nbytes, SPECK_NEON_CHUNK_SIZE); kernel_neon_begin(); (*crypt_many)(ctx->main_key.round_keys, ctx->main_key.nrounds, dst, src, count, &tweak); kernel_neon_end(); dst += count; src += count; nbytes -= count; } /* Handle any remainder with generic code */ while (nbytes >= sizeof(tweak)) { *(__le64 *)dst = *(__le64 *)src ^ tweak; (*crypt_one)(&ctx->main_key, dst, dst); *(__le64 *)dst ^= tweak; tweak = cpu_to_le64((le64_to_cpu(tweak) << 1) ^ ((tweak & cpu_to_le64(1ULL << 63)) ? 0x1B : 0)); dst += sizeof(tweak); src += sizeof(tweak); nbytes -= sizeof(tweak); } err = skcipher_walk_done(&walk, nbytes); } return err; } static int speck64_xts_encrypt(struct skcipher_request *req) { return __speck64_xts_crypt(req, crypto_speck64_encrypt, speck64_xts_encrypt_neon); } static int speck64_xts_decrypt(struct skcipher_request *req) { return __speck64_xts_crypt(req, crypto_speck64_decrypt, speck64_xts_decrypt_neon); } static int speck64_xts_setkey(struct crypto_skcipher *tfm, const u8 *key, unsigned int keylen) { struct speck64_xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm); int err; err = xts_verify_key(tfm, key, keylen); if (err) return err; keylen /= 2; err = crypto_speck64_setkey(&ctx->main_key, key, keylen); if (err) return err; return crypto_speck64_setkey(&ctx->tweak_key, key + keylen, keylen); } static struct skcipher_alg speck_algs[] = { { .base.cra_name = "xts(speck128)", .base.cra_driver_name = "xts-speck128-neon", .base.cra_priority = 300, .base.cra_blocksize = SPECK128_BLOCK_SIZE, .base.cra_ctxsize = sizeof(struct speck128_xts_tfm_ctx), .base.cra_alignmask = 7, .base.cra_module = THIS_MODULE, .min_keysize = 2 * SPECK128_128_KEY_SIZE, .max_keysize = 2 * SPECK128_256_KEY_SIZE, .ivsize = SPECK128_BLOCK_SIZE, .walksize = SPECK_NEON_CHUNK_SIZE, .setkey = speck128_xts_setkey, .encrypt = speck128_xts_encrypt, .decrypt = speck128_xts_decrypt, }, { .base.cra_name = "xts(speck64)", .base.cra_driver_name = "xts-speck64-neon", .base.cra_priority = 300, .base.cra_blocksize = SPECK64_BLOCK_SIZE, .base.cra_ctxsize = sizeof(struct speck64_xts_tfm_ctx), .base.cra_alignmask = 7, .base.cra_module = THIS_MODULE, .min_keysize = 2 * SPECK64_96_KEY_SIZE, .max_keysize = 2 * SPECK64_128_KEY_SIZE, .ivsize = SPECK64_BLOCK_SIZE, .walksize = SPECK_NEON_CHUNK_SIZE, .setkey = speck64_xts_setkey, .encrypt = speck64_xts_encrypt, .decrypt = speck64_xts_decrypt, } }; static int __init speck_neon_module_init(void) { if (!(elf_hwcap & HWCAP_NEON)) return -ENODEV; return crypto_register_skciphers(speck_algs, ARRAY_SIZE(speck_algs)); } static void __exit speck_neon_module_exit(void) { crypto_unregister_skciphers(speck_algs, ARRAY_SIZE(speck_algs)); } module_init(speck_neon_module_init); module_exit(speck_neon_module_exit); MODULE_DESCRIPTION("Speck block cipher (NEON-accelerated)"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Eric Biggers "); MODULE_ALIAS_CRYPTO("xts(speck128)"); MODULE_ALIAS_CRYPTO("xts-speck128-neon"); MODULE_ALIAS_CRYPTO("xts(speck64)"); MODULE_ALIAS_CRYPTO("xts-speck64-neon");