1 // SPDX-License-Identifier: GPL-2.0-only 2 /** 3 * AES XTS routines supporting VMX In-core instructions on Power 8 4 * 5 * Copyright (C) 2015 International Business Machines Inc. 6 * 7 * Author: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com> 8 */ 9 10 #include <asm/simd.h> 11 #include <asm/switch_to.h> 12 #include <crypto/aes.h> 13 #include <crypto/internal/simd.h> 14 #include <crypto/internal/skcipher.h> 15 #include <crypto/xts.h> 16 17 #include "aesp8-ppc.h" 18 19 struct p8_aes_xts_ctx { 20 struct crypto_skcipher *fallback; 21 struct aes_key enc_key; 22 struct aes_key dec_key; 23 struct aes_key tweak_key; 24 }; 25 26 static int p8_aes_xts_init(struct crypto_skcipher *tfm) 27 { 28 struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm); 29 struct crypto_skcipher *fallback; 30 31 fallback = crypto_alloc_skcipher("xts(aes)", 0, 32 CRYPTO_ALG_NEED_FALLBACK | 33 CRYPTO_ALG_ASYNC); 34 if (IS_ERR(fallback)) { 35 pr_err("Failed to allocate xts(aes) fallback: %ld\n", 36 PTR_ERR(fallback)); 37 return PTR_ERR(fallback); 38 } 39 40 crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) + 41 crypto_skcipher_reqsize(fallback)); 42 ctx->fallback = fallback; 43 return 0; 44 } 45 46 static void p8_aes_xts_exit(struct crypto_skcipher *tfm) 47 { 48 struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm); 49 50 crypto_free_skcipher(ctx->fallback); 51 } 52 53 static int p8_aes_xts_setkey(struct crypto_skcipher *tfm, const u8 *key, 54 unsigned int keylen) 55 { 56 struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm); 57 int ret; 58 59 ret = xts_verify_key(tfm, key, keylen); 60 if (ret) 61 return ret; 62 63 preempt_disable(); 64 pagefault_disable(); 65 enable_kernel_vsx(); 66 ret = aes_p8_set_encrypt_key(key + keylen/2, (keylen/2) * 8, &ctx->tweak_key); 67 ret |= aes_p8_set_encrypt_key(key, (keylen/2) * 8, &ctx->enc_key); 68 ret |= aes_p8_set_decrypt_key(key, (keylen/2) * 8, &ctx->dec_key); 69 disable_kernel_vsx(); 70 pagefault_enable(); 71 preempt_enable(); 72 73 ret |= crypto_skcipher_setkey(ctx->fallback, key, keylen); 74 75 return ret ? -EINVAL : 0; 76 } 77 78 static int p8_aes_xts_crypt(struct skcipher_request *req, int enc) 79 { 80 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); 81 const struct p8_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm); 82 struct skcipher_walk walk; 83 unsigned int nbytes; 84 u8 tweak[AES_BLOCK_SIZE]; 85 int ret; 86 87 if (!crypto_simd_usable() || (req->cryptlen % XTS_BLOCK_SIZE) != 0) { 88 struct skcipher_request *subreq = skcipher_request_ctx(req); 89 90 *subreq = *req; 91 skcipher_request_set_tfm(subreq, ctx->fallback); 92 return enc ? crypto_skcipher_encrypt(subreq) : 93 crypto_skcipher_decrypt(subreq); 94 } 95 96 ret = skcipher_walk_virt(&walk, req, false); 97 if (ret) 98 return ret; 99 100 preempt_disable(); 101 pagefault_disable(); 102 enable_kernel_vsx(); 103 104 aes_p8_encrypt(walk.iv, tweak, &ctx->tweak_key); 105 106 disable_kernel_vsx(); 107 pagefault_enable(); 108 preempt_enable(); 109 110 while ((nbytes = walk.nbytes) != 0) { 111 preempt_disable(); 112 pagefault_disable(); 113 enable_kernel_vsx(); 114 if (enc) 115 aes_p8_xts_encrypt(walk.src.virt.addr, 116 walk.dst.virt.addr, 117 round_down(nbytes, AES_BLOCK_SIZE), 118 &ctx->enc_key, NULL, tweak); 119 else 120 aes_p8_xts_decrypt(walk.src.virt.addr, 121 walk.dst.virt.addr, 122 round_down(nbytes, AES_BLOCK_SIZE), 123 &ctx->dec_key, NULL, tweak); 124 disable_kernel_vsx(); 125 pagefault_enable(); 126 preempt_enable(); 127 128 ret = skcipher_walk_done(&walk, nbytes % AES_BLOCK_SIZE); 129 } 130 return ret; 131 } 132 133 static int p8_aes_xts_encrypt(struct skcipher_request *req) 134 { 135 return p8_aes_xts_crypt(req, 1); 136 } 137 138 static int p8_aes_xts_decrypt(struct skcipher_request *req) 139 { 140 return p8_aes_xts_crypt(req, 0); 141 } 142 143 struct skcipher_alg p8_aes_xts_alg = { 144 .base.cra_name = "xts(aes)", 145 .base.cra_driver_name = "p8_aes_xts", 146 .base.cra_module = THIS_MODULE, 147 .base.cra_priority = 2000, 148 .base.cra_flags = CRYPTO_ALG_NEED_FALLBACK, 149 .base.cra_blocksize = AES_BLOCK_SIZE, 150 .base.cra_ctxsize = sizeof(struct p8_aes_xts_ctx), 151 .setkey = p8_aes_xts_setkey, 152 .encrypt = p8_aes_xts_encrypt, 153 .decrypt = p8_aes_xts_decrypt, 154 .init = p8_aes_xts_init, 155 .exit = p8_aes_xts_exit, 156 .min_keysize = 2 * AES_MIN_KEY_SIZE, 157 .max_keysize = 2 * AES_MAX_KEY_SIZE, 158 .ivsize = AES_BLOCK_SIZE, 159 }; 160