Add hardware accelerated version of XCTR for ARM64 CPUs with ARMv8 Crypto Extension support. This XCTR implementation is based on the CTR implementation in aes-modes.S. More information on XCTR can be found in the HCTR2 paper: Length-preserving encryption with HCTR2: https://eprint.iacr.org/2021/1441.pdf Signed-off-by: Nathan Huckleberry <nhuck@xxxxxxxxxx> --- Changes since v1: * Added STRIDE back to aes-glue.c arch/arm64/crypto/Kconfig | 4 +- arch/arm64/crypto/aes-glue.c | 72 ++++++++++++++++++- arch/arm64/crypto/aes-modes.S | 130 ++++++++++++++++++++++++++++++++++ 3 files changed, 202 insertions(+), 4 deletions(-) diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig index 2a965aa0188d..897f9a4b5b67 100644 --- a/arch/arm64/crypto/Kconfig +++ b/arch/arm64/crypto/Kconfig @@ -84,13 +84,13 @@ config CRYPTO_AES_ARM64_CE_CCM select CRYPTO_LIB_AES config CRYPTO_AES_ARM64_CE_BLK - tristate "AES in ECB/CBC/CTR/XTS modes using ARMv8 Crypto Extensions" + tristate "AES in ECB/CBC/CTR/XTS/XCTR modes using ARMv8 Crypto Extensions" depends on KERNEL_MODE_NEON select CRYPTO_SKCIPHER select CRYPTO_AES_ARM64_CE config CRYPTO_AES_ARM64_NEON_BLK - tristate "AES in ECB/CBC/CTR/XTS modes using NEON instructions" + tristate "AES in ECB/CBC/CTR/XTS/XCTR modes using NEON instructions" depends on KERNEL_MODE_NEON select CRYPTO_SKCIPHER select CRYPTO_LIB_AES diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c index 561dd2332571..dd04f3c5b0f1 100644 --- a/arch/arm64/crypto/aes-glue.c +++ b/arch/arm64/crypto/aes-glue.c @@ -24,6 +24,7 @@ #ifdef USE_V8_CRYPTO_EXTENSIONS #define MODE "ce" #define PRIO 300 +#define STRIDE 5 #define aes_expandkey ce_aes_expandkey #define aes_ecb_encrypt ce_aes_ecb_encrypt #define aes_ecb_decrypt ce_aes_ecb_decrypt @@ -34,13 +35,15 @@ #define aes_essiv_cbc_encrypt ce_aes_essiv_cbc_encrypt #define aes_essiv_cbc_decrypt ce_aes_essiv_cbc_decrypt #define aes_ctr_encrypt ce_aes_ctr_encrypt +#define aes_xctr_encrypt ce_aes_xctr_encrypt #define aes_xts_encrypt ce_aes_xts_encrypt #define aes_xts_decrypt ce_aes_xts_decrypt #define aes_mac_update ce_aes_mac_update -MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions"); +MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS/XCTR using ARMv8 Crypto Extensions"); #else #define MODE "neon" #define PRIO 200 +#define STRIDE 4 #define aes_ecb_encrypt neon_aes_ecb_encrypt #define aes_ecb_decrypt neon_aes_ecb_decrypt #define aes_cbc_encrypt neon_aes_cbc_encrypt @@ -50,16 +53,18 @@ MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions"); #define aes_essiv_cbc_encrypt neon_aes_essiv_cbc_encrypt #define aes_essiv_cbc_decrypt neon_aes_essiv_cbc_decrypt #define aes_ctr_encrypt neon_aes_ctr_encrypt +#define aes_xctr_encrypt neon_aes_xctr_encrypt #define aes_xts_encrypt neon_aes_xts_encrypt #define aes_xts_decrypt neon_aes_xts_decrypt #define aes_mac_update neon_aes_mac_update -MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 NEON"); +MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS/XCTR using ARMv8 NEON"); #endif #if defined(USE_V8_CRYPTO_EXTENSIONS) || !IS_ENABLED(CONFIG_CRYPTO_AES_ARM64_BS) MODULE_ALIAS_CRYPTO("ecb(aes)"); MODULE_ALIAS_CRYPTO("cbc(aes)"); MODULE_ALIAS_CRYPTO("ctr(aes)"); MODULE_ALIAS_CRYPTO("xts(aes)"); +MODULE_ALIAS_CRYPTO("xctr(aes)"); #endif MODULE_ALIAS_CRYPTO("cts(cbc(aes))"); MODULE_ALIAS_CRYPTO("essiv(cbc(aes),sha256)"); @@ -89,6 +94,10 @@ asmlinkage void aes_cbc_cts_decrypt(u8 out[], u8 const in[], u32 const rk[], asmlinkage void aes_ctr_encrypt(u8 out[], u8 const in[], u32 const rk[], int rounds, int bytes, u8 ctr[]); +asmlinkage void aes_xctr_encrypt(u8 out[], u8 const in[], u32 const rk[], + int rounds, int bytes, u8 ctr[], u8 finalbuf[], + int byte_ctr); + asmlinkage void aes_xts_encrypt(u8 out[], u8 const in[], u32 const rk1[], int rounds, int bytes, u32 const rk2[], u8 iv[], int first); @@ -442,6 +451,49 @@ static int __maybe_unused essiv_cbc_decrypt(struct skcipher_request *req) return err ?: cbc_decrypt_walk(req, &walk); } +static int __maybe_unused xctr_encrypt(struct skcipher_request *req) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm); + int err, rounds = 6 + ctx->key_length / 4; + struct skcipher_walk walk; + unsigned int byte_ctr = 0; + + err = skcipher_walk_virt(&walk, req, false); + + while (walk.nbytes > 0) { + const u8 *src = walk.src.virt.addr; + unsigned int nbytes = walk.nbytes; + u8 *dst = walk.dst.virt.addr; + u8 buf[AES_BLOCK_SIZE]; + unsigned int tail; + + if (unlikely(nbytes < AES_BLOCK_SIZE)) + src = memcpy(buf, src, nbytes); + else if (nbytes < walk.total) + nbytes &= ~(AES_BLOCK_SIZE - 1); + + kernel_neon_begin(); + aes_xctr_encrypt(dst, src, ctx->key_enc, rounds, nbytes, + walk.iv, buf, byte_ctr); + kernel_neon_end(); + + tail = nbytes % (STRIDE * AES_BLOCK_SIZE); + if (tail > 0 && tail < AES_BLOCK_SIZE) + /* + * The final partial block could not be returned using + * an overlapping store, so it was passed via buf[] + * instead. + */ + memcpy(dst + nbytes - tail, buf, tail); + byte_ctr += nbytes; + + err = skcipher_walk_done(&walk, walk.nbytes - nbytes); + } + + return err; +} + static int __maybe_unused ctr_encrypt(struct skcipher_request *req) { struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); @@ -669,6 +721,22 @@ static struct skcipher_alg aes_algs[] = { { .setkey = skcipher_aes_setkey, .encrypt = ctr_encrypt, .decrypt = ctr_encrypt, +}, { + .base = { + .cra_name = "xctr(aes)", + .cra_driver_name = "xctr-aes-" MODE, + .cra_priority = PRIO, + .cra_blocksize = 1, + .cra_ctxsize = sizeof(struct crypto_aes_ctx), + .cra_module = THIS_MODULE, + }, + .min_keysize = AES_MIN_KEY_SIZE, + .max_keysize = AES_MAX_KEY_SIZE, + .ivsize = AES_BLOCK_SIZE, + .chunksize = AES_BLOCK_SIZE, + .setkey = skcipher_aes_setkey, + .encrypt = xctr_encrypt, + .decrypt = xctr_encrypt, }, { .base = { .cra_name = "xts(aes)", diff --git a/arch/arm64/crypto/aes-modes.S b/arch/arm64/crypto/aes-modes.S index dc35eb0245c5..3b5c7a5c21e4 100644 --- a/arch/arm64/crypto/aes-modes.S +++ b/arch/arm64/crypto/aes-modes.S @@ -479,6 +479,136 @@ ST5( mov v3.16b, v4.16b ) b .Lctrout AES_FUNC_END(aes_ctr_encrypt) + /* + * aes_xctr_encrypt(u8 out[], u8 const in[], u8 const rk[], int rounds, + * int bytes, u8 const ctr[], u8 finalbuf[], int + * byte_ctr) + */ + +AES_FUNC_START(aes_xctr_encrypt) + stp x29, x30, [sp, #-16]! + mov x29, sp + + enc_prepare w3, x2, x12 + ld1 {vctr.16b}, [x5] + + umov x12, vctr.d[0] /* keep ctr in reg */ + lsr x7, x7, #4 + add x11, x7, #1 + +.LxctrloopNx: + add w7, w4, #15 + sub w4, w4, #MAX_STRIDE << 4 + lsr w7, w7, #4 + mov w8, #MAX_STRIDE + cmp w7, w8 + csel w7, w7, w8, lt + add x11, x11, x7 + + mov v0.16b, vctr.16b + mov v1.16b, vctr.16b + mov v2.16b, vctr.16b + mov v3.16b, vctr.16b +ST5( mov v4.16b, vctr.16b ) + + sub x7, x11, #MAX_STRIDE + eor x7, x12, x7 + ins v0.d[0], x7 + sub x7, x11, #MAX_STRIDE - 1 + sub x8, x11, #MAX_STRIDE - 2 + eor x7, x7, x12 + sub x9, x11, #MAX_STRIDE - 3 + mov v1.d[0], x7 + eor x8, x8, x12 + eor x9, x9, x12 +ST5( sub x10, x11, #MAX_STRIDE - 4) + mov v2.d[0], x8 + eor x10, x10, x12 + mov v3.d[0], x9 +ST5( mov v4.d[0], x10 ) + tbnz w4, #31, .Lxctrtail + ld1 {v5.16b-v7.16b}, [x1], #48 +ST4( bl aes_encrypt_block4x ) +ST5( bl aes_encrypt_block5x ) + eor v0.16b, v5.16b, v0.16b +ST4( ld1 {v5.16b}, [x1], #16 ) + eor v1.16b, v6.16b, v1.16b +ST5( ld1 {v5.16b-v6.16b}, [x1], #32 ) + eor v2.16b, v7.16b, v2.16b + eor v3.16b, v5.16b, v3.16b +ST5( eor v4.16b, v6.16b, v4.16b ) + st1 {v0.16b-v3.16b}, [x0], #64 +ST5( st1 {v4.16b}, [x0], #16 ) + cbz w4, .Lxctrout + b .LxctrloopNx + +.Lxctrout: + ldp x29, x30, [sp], #16 + ret + +.Lxctrtail: + /* XOR up to MAX_STRIDE * 16 - 1 bytes of in/output with v0 ... v3/v4 */ + mov x17, #16 + ands x13, x4, #0xf + csel x13, x13, x17, ne + +ST5( cmp w4, #64 - (MAX_STRIDE << 4)) +ST5( csel x14, x17, xzr, gt ) + cmp w4, #48 - (MAX_STRIDE << 4) + csel x15, x17, xzr, gt + cmp w4, #32 - (MAX_STRIDE << 4) + csel x16, x17, xzr, gt + cmp w4, #16 - (MAX_STRIDE << 4) + ble .Lxctrtail1x + +ST5( mov v4.d[0], x10 ) + + adr_l x12, .Lcts_permute_table + add x12, x12, x13 + +ST5( ld1 {v5.16b}, [x1], x14 ) + ld1 {v6.16b}, [x1], x15 + ld1 {v7.16b}, [x1], x16 + +ST4( bl aes_encrypt_block4x ) +ST5( bl aes_encrypt_block5x ) + + ld1 {v8.16b}, [x1], x13 + ld1 {v9.16b}, [x1] + ld1 {v10.16b}, [x12] + +ST4( eor v6.16b, v6.16b, v0.16b ) +ST4( eor v7.16b, v7.16b, v1.16b ) +ST4( tbl v3.16b, {v3.16b}, v10.16b ) +ST4( eor v8.16b, v8.16b, v2.16b ) +ST4( eor v9.16b, v9.16b, v3.16b ) + +ST5( eor v5.16b, v5.16b, v0.16b ) +ST5( eor v6.16b, v6.16b, v1.16b ) +ST5( tbl v4.16b, {v4.16b}, v10.16b ) +ST5( eor v7.16b, v7.16b, v2.16b ) +ST5( eor v8.16b, v8.16b, v3.16b ) +ST5( eor v9.16b, v9.16b, v4.16b ) + +ST5( st1 {v5.16b}, [x0], x14 ) + st1 {v6.16b}, [x0], x15 + st1 {v7.16b}, [x0], x16 + add x13, x13, x0 + st1 {v9.16b}, [x13] // overlapping stores + st1 {v8.16b}, [x0] + b .Lxctrout + +.Lxctrtail1x: + // use finalbuf if less than a full block + csel x0, x0, x6, eq + ld1 {v5.16b}, [x1] +ST5( mov v3.16b, v4.16b ) + encrypt_block v3, w3, x2, x8, w7 + eor v5.16b, v5.16b, v3.16b + st1 {v5.16b}, [x0] + b .Lxctrout +AES_FUNC_END(aes_xctr_encrypt) + /* * aes_xts_encrypt(u8 out[], u8 const in[], u8 const rk1[], int rounds, -- 2.35.1.265.g69c8d7142f-goog
