From 5092fcf3490811a735ef44bd22d8b5ff1bd63926 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 24 Jul 2017 11:28:12 +0100 Subject: [PATCH] crypto: arm64/aes-ce-ccm: add non-SIMD generic fallback The arm64 kernel will shortly disallow nested kernel mode NEON. So honour this in the ARMv8 Crypto Extensions implementation of CCM-AES, and fall back to a scalar implementation using the generic crypto helpers for AES, XOR and incrementing the CTR counter. Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu --- arch/arm64/crypto/Kconfig | 1 + arch/arm64/crypto/aes-ce-ccm-glue.c | 174 ++++++++++++++++++++++------ 2 files changed, 140 insertions(+), 35 deletions(-) diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig index 2fd4bb6d0b5a..ba637765c19a 100644 --- a/arch/arm64/crypto/Kconfig +++ b/arch/arm64/crypto/Kconfig @@ -59,6 +59,7 @@ config CRYPTO_AES_ARM64_CE_CCM depends on ARM64 && KERNEL_MODE_NEON select CRYPTO_ALGAPI select CRYPTO_AES_ARM64_CE + select CRYPTO_AES_ARM64 select CRYPTO_AEAD config CRYPTO_AES_ARM64_CE_BLK diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c index 6a7dbc7c83a6..a1254036f2b1 100644 --- a/arch/arm64/crypto/aes-ce-ccm-glue.c +++ b/arch/arm64/crypto/aes-ce-ccm-glue.c @@ -1,7 +1,7 @@ /* * aes-ccm-glue.c - AES-CCM transform for ARMv8 with Crypto Extensions * - * Copyright (C) 2013 - 2014 Linaro Ltd + * Copyright (C) 2013 - 2017 Linaro Ltd * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as @@ -9,6 +9,7 @@ */ #include +#include #include #include #include @@ -44,6 +45,8 @@ asmlinkage void ce_aes_ccm_decrypt(u8 out[], u8 const in[], u32 cbytes, asmlinkage void ce_aes_ccm_final(u8 mac[], u8 const ctr[], u32 const rk[], u32 rounds); +asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds); + static int ccm_setkey(struct crypto_aead *tfm, const u8 *in_key, unsigned int key_len) { @@ -103,7 +106,45 @@ static int ccm_init_mac(struct aead_request *req, u8 maciv[], u32 msglen) return 0; } -static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[]) +static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[], + u32 abytes, u32 *macp, bool use_neon) +{ + if (likely(use_neon)) { + ce_aes_ccm_auth_data(mac, in, abytes, macp, key->key_enc, + num_rounds(key)); + } else { + if (*macp > 0 && *macp < AES_BLOCK_SIZE) { + int added = min(abytes, AES_BLOCK_SIZE - *macp); + + crypto_xor(&mac[*macp], in, added); + + *macp += added; + in += added; + abytes -= added; + } + + while (abytes > AES_BLOCK_SIZE) { + __aes_arm64_encrypt(key->key_enc, mac, mac, + num_rounds(key)); + crypto_xor(mac, in, AES_BLOCK_SIZE); + + in += AES_BLOCK_SIZE; + abytes -= AES_BLOCK_SIZE; + } + + if (abytes > 0) { + __aes_arm64_encrypt(key->key_enc, mac, mac, + num_rounds(key)); + crypto_xor(mac, in, abytes); + *macp = abytes; + } else { + *macp = 0; + } + } +} + +static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[], + bool use_neon) { struct crypto_aead *aead = crypto_aead_reqtfm(req); struct crypto_aes_ctx *ctx = crypto_aead_ctx(aead); @@ -122,8 +163,7 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[]) ltag.len = 6; } - ce_aes_ccm_auth_data(mac, (u8 *)<ag, ltag.len, &macp, ctx->key_enc, - num_rounds(ctx)); + ccm_update_mac(ctx, mac, (u8 *)<ag, ltag.len, &macp, use_neon); scatterwalk_start(&walk, req->src); do { @@ -135,8 +175,7 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[]) n = scatterwalk_clamp(&walk, len); } p = scatterwalk_map(&walk); - ce_aes_ccm_auth_data(mac, p, n, &macp, ctx->key_enc, - num_rounds(ctx)); + ccm_update_mac(ctx, mac, p, n, &macp, use_neon); len -= n; scatterwalk_unmap(p); @@ -145,6 +184,56 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[]) } while (len); } +static int ccm_crypt_fallback(struct skcipher_walk *walk, u8 mac[], u8 iv0[], + struct crypto_aes_ctx *ctx, bool enc) +{ + u8 buf[AES_BLOCK_SIZE]; + int err = 0; + + while (walk->nbytes) { + int blocks = walk->nbytes / AES_BLOCK_SIZE; + u32 tail = walk->nbytes % AES_BLOCK_SIZE; + u8 *dst = walk->dst.virt.addr; + u8 *src = walk->src.virt.addr; + u32 nbytes = walk->nbytes; + + if (nbytes == walk->total && tail > 0) { + blocks++; + tail = 0; + } + + do { + u32 bsize = AES_BLOCK_SIZE; + + if (nbytes < AES_BLOCK_SIZE) + bsize = nbytes; + + crypto_inc(walk->iv, AES_BLOCK_SIZE); + __aes_arm64_encrypt(ctx->key_enc, buf, walk->iv, + num_rounds(ctx)); + __aes_arm64_encrypt(ctx->key_enc, mac, mac, + num_rounds(ctx)); + if (enc) + crypto_xor(mac, src, bsize); + crypto_xor_cpy(dst, src, buf, bsize); + if (!enc) + crypto_xor(mac, dst, bsize); + dst += bsize; + src += bsize; + nbytes -= bsize; + } while (--blocks); + + err = skcipher_walk_done(walk, tail); + } + + if (!err) { + __aes_arm64_encrypt(ctx->key_enc, buf, iv0, num_rounds(ctx)); + __aes_arm64_encrypt(ctx->key_enc, mac, mac, num_rounds(ctx)); + crypto_xor(mac, buf, AES_BLOCK_SIZE); + } + return err; +} + static int ccm_encrypt(struct aead_request *req) { struct crypto_aead *aead = crypto_aead_reqtfm(req); @@ -153,39 +242,46 @@ static int ccm_encrypt(struct aead_request *req) u8 __aligned(8) mac[AES_BLOCK_SIZE]; u8 buf[AES_BLOCK_SIZE]; u32 len = req->cryptlen; + bool use_neon = may_use_simd(); int err; err = ccm_init_mac(req, mac, len); if (err) return err; - kernel_neon_begin_partial(6); + if (likely(use_neon)) + kernel_neon_begin(); if (req->assoclen) - ccm_calculate_auth_mac(req, mac); + ccm_calculate_auth_mac(req, mac, use_neon); /* preserve the original iv for the final round */ memcpy(buf, req->iv, AES_BLOCK_SIZE); err = skcipher_walk_aead_encrypt(&walk, req, true); - while (walk.nbytes) { - u32 tail = walk.nbytes % AES_BLOCK_SIZE; - - if (walk.nbytes == walk.total) - tail = 0; + if (likely(use_neon)) { + while (walk.nbytes) { + u32 tail = walk.nbytes % AES_BLOCK_SIZE; - ce_aes_ccm_encrypt(walk.dst.virt.addr, walk.src.virt.addr, - walk.nbytes - tail, ctx->key_enc, - num_rounds(ctx), mac, walk.iv); + if (walk.nbytes == walk.total) + tail = 0; - err = skcipher_walk_done(&walk, tail); - } - if (!err) - ce_aes_ccm_final(mac, buf, ctx->key_enc, num_rounds(ctx)); + ce_aes_ccm_encrypt(walk.dst.virt.addr, + walk.src.virt.addr, + walk.nbytes - tail, ctx->key_enc, + num_rounds(ctx), mac, walk.iv); - kernel_neon_end(); + err = skcipher_walk_done(&walk, tail); + } + if (!err) + ce_aes_ccm_final(mac, buf, ctx->key_enc, + num_rounds(ctx)); + kernel_neon_end(); + } else { + err = ccm_crypt_fallback(&walk, mac, buf, ctx, true); + } if (err) return err; @@ -205,38 +301,46 @@ static int ccm_decrypt(struct aead_request *req) u8 __aligned(8) mac[AES_BLOCK_SIZE]; u8 buf[AES_BLOCK_SIZE]; u32 len = req->cryptlen - authsize; + bool use_neon = may_use_simd(); int err; err = ccm_init_mac(req, mac, len); if (err) return err; - kernel_neon_begin_partial(6); + if (likely(use_neon)) + kernel_neon_begin(); if (req->assoclen) - ccm_calculate_auth_mac(req, mac); + ccm_calculate_auth_mac(req, mac, use_neon); /* preserve the original iv for the final round */ memcpy(buf, req->iv, AES_BLOCK_SIZE); err = skcipher_walk_aead_decrypt(&walk, req, true); - while (walk.nbytes) { - u32 tail = walk.nbytes % AES_BLOCK_SIZE; + if (likely(use_neon)) { + while (walk.nbytes) { + u32 tail = walk.nbytes % AES_BLOCK_SIZE; - if (walk.nbytes == walk.total) - tail = 0; + if (walk.nbytes == walk.total) + tail = 0; - ce_aes_ccm_decrypt(walk.dst.virt.addr, walk.src.virt.addr, - walk.nbytes - tail, ctx->key_enc, - num_rounds(ctx), mac, walk.iv); + ce_aes_ccm_decrypt(walk.dst.virt.addr, + walk.src.virt.addr, + walk.nbytes - tail, ctx->key_enc, + num_rounds(ctx), mac, walk.iv); - err = skcipher_walk_done(&walk, tail); - } - if (!err) - ce_aes_ccm_final(mac, buf, ctx->key_enc, num_rounds(ctx)); + err = skcipher_walk_done(&walk, tail); + } + if (!err) + ce_aes_ccm_final(mac, buf, ctx->key_enc, + num_rounds(ctx)); - kernel_neon_end(); + kernel_neon_end(); + } else { + err = ccm_crypt_fallback(&walk, mac, buf, ctx, false); + } if (err) return err; -- 2.30.2