From cc7cf991e9eb54cac7733dc7d8f3a8591ba6e1c3 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 3 Dec 2018 19:52:50 -0800 Subject: [PATCH] crypto: arm64/chacha20 - add XChaCha20 support Add an XChaCha20 implementation that is hooked up to the ARM64 NEON implementation of ChaCha20. This can be used by Adiantum. A NEON implementation of single-block HChaCha20 is also added so that XChaCha20 can use it rather than the generic implementation. This required refactoring the ChaCha20 permutation into its own function. Signed-off-by: Eric Biggers Reviewed-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- arch/arm64/crypto/Kconfig | 2 +- arch/arm64/crypto/chacha20-neon-core.S | 65 ++++++++++++----- arch/arm64/crypto/chacha20-neon-glue.c | 99 +++++++++++++++++++------- 3 files changed, 124 insertions(+), 42 deletions(-) diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig index 3f5aeb786192..d54ddb8468ef 100644 --- a/arch/arm64/crypto/Kconfig +++ b/arch/arm64/crypto/Kconfig @@ -101,7 +101,7 @@ config CRYPTO_AES_ARM64_NEON_BLK select CRYPTO_SIMD config CRYPTO_CHACHA20_NEON - tristate "NEON accelerated ChaCha20 symmetric cipher" + tristate "ChaCha20 and XChaCha20 stream ciphers using NEON instructions" depends on KERNEL_MODE_NEON select CRYPTO_BLKCIPHER select CRYPTO_CHACHA20 diff --git a/arch/arm64/crypto/chacha20-neon-core.S b/arch/arm64/crypto/chacha20-neon-core.S index 13c85e272c2a..0571e45a1a0a 100644 --- a/arch/arm64/crypto/chacha20-neon-core.S +++ b/arch/arm64/crypto/chacha20-neon-core.S @@ -23,25 +23,20 @@ .text .align 6 -ENTRY(chacha20_block_xor_neon) - // x0: Input state matrix, s - // x1: 1 data block output, o - // x2: 1 data block input, i - - // - // This function encrypts one ChaCha20 block by loading the state matrix - // in four NEON registers. It performs matrix operation on four words in - // parallel, but requires shuffling to rearrange the words after each - // round. - // - - // x0..3 = s0..3 - adr x3, ROT8 - ld1 {v0.4s-v3.4s}, [x0] - ld1 {v8.4s-v11.4s}, [x0] - ld1 {v12.4s}, [x3] +/* + * chacha20_permute - permute one block + * + * Permute one 64-byte block where the state matrix is stored in the four NEON + * registers v0-v3. It performs matrix operations on four words in parallel, + * but requires shuffling to rearrange the words after each round. + * + * Clobbers: x3, x10, v4, v12 + */ +chacha20_permute: mov x3, #10 + adr x10, ROT8 + ld1 {v12.4s}, [x10] .Ldoubleround: // x0 += x1, x3 = rotl32(x3 ^ x0, 16) @@ -105,6 +100,23 @@ ENTRY(chacha20_block_xor_neon) subs x3, x3, #1 b.ne .Ldoubleround + ret +ENDPROC(chacha20_permute) + +ENTRY(chacha20_block_xor_neon) + // x0: Input state matrix, s + // x1: 1 data block output, o + // x2: 1 data block input, i + + stp x29, x30, [sp, #-16]! + mov x29, sp + + // x0..3 = s0..3 + ld1 {v0.4s-v3.4s}, [x0] + ld1 {v8.4s-v11.4s}, [x0] + + bl chacha20_permute + ld1 {v4.16b-v7.16b}, [x2] // o0 = i0 ^ (x0 + s0) @@ -125,9 +137,28 @@ ENTRY(chacha20_block_xor_neon) st1 {v0.16b-v3.16b}, [x1] + ldp x29, x30, [sp], #16 ret ENDPROC(chacha20_block_xor_neon) +ENTRY(hchacha20_block_neon) + // x0: Input state matrix, s + // x1: output (8 32-bit words) + + stp x29, x30, [sp, #-16]! + mov x29, sp + + ld1 {v0.4s-v3.4s}, [x0] + + bl chacha20_permute + + st1 {v0.16b}, [x1], #16 + st1 {v3.16b}, [x1] + + ldp x29, x30, [sp], #16 + ret +ENDPROC(hchacha20_block_neon) + .align 6 ENTRY(chacha20_4block_xor_neon) // x0: Input state matrix, s diff --git a/arch/arm64/crypto/chacha20-neon-glue.c b/arch/arm64/crypto/chacha20-neon-glue.c index 96e0cfb8c3f5..a5b9cbc0c4de 100644 --- a/arch/arm64/crypto/chacha20-neon-glue.c +++ b/arch/arm64/crypto/chacha20-neon-glue.c @@ -30,6 +30,7 @@ asmlinkage void chacha20_block_xor_neon(u32 *state, u8 *dst, const u8 *src); asmlinkage void chacha20_4block_xor_neon(u32 *state, u8 *dst, const u8 *src); +asmlinkage void hchacha20_block_neon(const u32 *state, u32 *out); static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src, unsigned int bytes) @@ -65,20 +66,16 @@ static void chacha20_doneon(u32 *state, u8 *dst, const u8 *src, kernel_neon_end(); } -static int chacha20_neon(struct skcipher_request *req) +static int chacha20_neon_stream_xor(struct skcipher_request *req, + struct chacha_ctx *ctx, u8 *iv) { - struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); - struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm); struct skcipher_walk walk; u32 state[16]; int err; - if (!may_use_simd() || req->cryptlen <= CHACHA_BLOCK_SIZE) - return crypto_chacha_crypt(req); - err = skcipher_walk_virt(&walk, req, false); - crypto_chacha_init(state, ctx, walk.iv); + crypto_chacha_init(state, ctx, iv); while (walk.nbytes > 0) { unsigned int nbytes = walk.nbytes; @@ -94,22 +91,73 @@ static int chacha20_neon(struct skcipher_request *req) return err; } -static struct skcipher_alg alg = { - .base.cra_name = "chacha20", - .base.cra_driver_name = "chacha20-neon", - .base.cra_priority = 300, - .base.cra_blocksize = 1, - .base.cra_ctxsize = sizeof(struct chacha_ctx), - .base.cra_module = THIS_MODULE, +static int chacha20_neon(struct skcipher_request *req) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm); - .min_keysize = CHACHA_KEY_SIZE, - .max_keysize = CHACHA_KEY_SIZE, - .ivsize = CHACHA_IV_SIZE, - .chunksize = CHACHA_BLOCK_SIZE, - .walksize = 4 * CHACHA_BLOCK_SIZE, - .setkey = crypto_chacha20_setkey, - .encrypt = chacha20_neon, - .decrypt = chacha20_neon, + if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd()) + return crypto_chacha_crypt(req); + + return chacha20_neon_stream_xor(req, ctx, req->iv); +} + +static int xchacha20_neon(struct skcipher_request *req) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm); + struct chacha_ctx subctx; + u32 state[16]; + u8 real_iv[16]; + + if (req->cryptlen <= CHACHA_BLOCK_SIZE || !may_use_simd()) + return crypto_xchacha_crypt(req); + + crypto_chacha_init(state, ctx, req->iv); + + kernel_neon_begin(); + hchacha20_block_neon(state, subctx.key); + kernel_neon_end(); + + memcpy(&real_iv[0], req->iv + 24, 8); + memcpy(&real_iv[8], req->iv + 16, 8); + return chacha20_neon_stream_xor(req, &subctx, real_iv); +} + +static struct skcipher_alg algs[] = { + { + .base.cra_name = "chacha20", + .base.cra_driver_name = "chacha20-neon", + .base.cra_priority = 300, + .base.cra_blocksize = 1, + .base.cra_ctxsize = sizeof(struct chacha_ctx), + .base.cra_module = THIS_MODULE, + + .min_keysize = CHACHA_KEY_SIZE, + .max_keysize = CHACHA_KEY_SIZE, + .ivsize = CHACHA_IV_SIZE, + .chunksize = CHACHA_BLOCK_SIZE, + .walksize = 4 * CHACHA_BLOCK_SIZE, + .setkey = crypto_chacha20_setkey, + .encrypt = chacha20_neon, + .decrypt = chacha20_neon, + }, { + .base.cra_name = "xchacha20", + .base.cra_driver_name = "xchacha20-neon", + .base.cra_priority = 300, + .base.cra_blocksize = 1, + .base.cra_ctxsize = sizeof(struct chacha_ctx), + .base.cra_module = THIS_MODULE, + + .min_keysize = CHACHA_KEY_SIZE, + .max_keysize = CHACHA_KEY_SIZE, + .ivsize = XCHACHA_IV_SIZE, + .chunksize = CHACHA_BLOCK_SIZE, + .walksize = 4 * CHACHA_BLOCK_SIZE, + .setkey = crypto_chacha20_setkey, + .encrypt = xchacha20_neon, + .decrypt = xchacha20_neon, + } }; static int __init chacha20_simd_mod_init(void) @@ -117,12 +165,12 @@ static int __init chacha20_simd_mod_init(void) if (!(elf_hwcap & HWCAP_ASIMD)) return -ENODEV; - return crypto_register_skcipher(&alg); + return crypto_register_skciphers(algs, ARRAY_SIZE(algs)); } static void __exit chacha20_simd_mod_fini(void) { - crypto_unregister_skcipher(&alg); + crypto_unregister_skciphers(algs, ARRAY_SIZE(algs)); } module_init(chacha20_simd_mod_init); @@ -131,3 +179,6 @@ module_exit(chacha20_simd_mod_fini); MODULE_AUTHOR("Ard Biesheuvel "); MODULE_LICENSE("GPL v2"); MODULE_ALIAS_CRYPTO("chacha20"); +MODULE_ALIAS_CRYPTO("chacha20-neon"); +MODULE_ALIAS_CRYPTO("xchacha20"); +MODULE_ALIAS_CRYPTO("xchacha20-neon");