1 /** 2 * GHASH routines supporting VMX instructions on the Power 8 3 * 4 * Copyright (C) 2015 International Business Machines Inc. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; version 2 only. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 18 * 19 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com> 20 */ 21 22 #include <linux/types.h> 23 #include <linux/err.h> 24 #include <linux/crypto.h> 25 #include <linux/delay.h> 26 #include <linux/hardirq.h> 27 #include <asm/switch_to.h> 28 #include <crypto/aes.h> 29 #include <crypto/ghash.h> 30 #include <crypto/scatterwalk.h> 31 #include <crypto/internal/hash.h> 32 #include <crypto/b128ops.h> 33 34 #define IN_INTERRUPT in_interrupt() 35 36 void gcm_init_p8(u128 htable[16], const u64 Xi[2]); 37 void gcm_gmult_p8(u64 Xi[2], const u128 htable[16]); 38 void gcm_ghash_p8(u64 Xi[2], const u128 htable[16], 39 const u8 *in, size_t len); 40 41 struct p8_ghash_ctx { 42 u128 htable[16]; 43 struct crypto_shash *fallback; 44 }; 45 46 struct p8_ghash_desc_ctx { 47 u64 shash[2]; 48 u8 buffer[GHASH_DIGEST_SIZE]; 49 int bytes; 50 struct shash_desc fallback_desc; 51 }; 52 53 static int p8_ghash_init_tfm(struct crypto_tfm *tfm) 54 { 55 const char *alg = "ghash-generic"; 56 struct crypto_shash *fallback; 57 struct crypto_shash *shash_tfm = __crypto_shash_cast(tfm); 58 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm); 59 60 fallback = crypto_alloc_shash(alg, 0, CRYPTO_ALG_NEED_FALLBACK); 61 if (IS_ERR(fallback)) { 62 printk(KERN_ERR 63 "Failed to allocate transformation for '%s': %ld\n", 64 alg, PTR_ERR(fallback)); 65 return PTR_ERR(fallback); 66 } 67 printk(KERN_INFO "Using '%s' as fallback implementation.\n", 68 crypto_tfm_alg_driver_name(crypto_shash_tfm(fallback))); 69 70 crypto_shash_set_flags(fallback, 71 crypto_shash_get_flags((struct crypto_shash 72 *) tfm)); 73 74 /* Check if the descsize defined in the algorithm is still enough. */ 75 if (shash_tfm->descsize < sizeof(struct p8_ghash_desc_ctx) 76 + crypto_shash_descsize(fallback)) { 77 printk(KERN_ERR 78 "Desc size of the fallback implementation (%s) does not match the expected value: %lu vs %u\n", 79 alg, 80 shash_tfm->descsize - sizeof(struct p8_ghash_desc_ctx), 81 crypto_shash_descsize(fallback)); 82 return -EINVAL; 83 } 84 ctx->fallback = fallback; 85 86 return 0; 87 } 88 89 static void p8_ghash_exit_tfm(struct crypto_tfm *tfm) 90 { 91 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm); 92 93 if (ctx->fallback) { 94 crypto_free_shash(ctx->fallback); 95 ctx->fallback = NULL; 96 } 97 } 98 99 static int p8_ghash_init(struct shash_desc *desc) 100 { 101 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm)); 102 struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc); 103 104 dctx->bytes = 0; 105 memset(dctx->shash, 0, GHASH_DIGEST_SIZE); 106 dctx->fallback_desc.tfm = ctx->fallback; 107 dctx->fallback_desc.flags = desc->flags; 108 return crypto_shash_init(&dctx->fallback_desc); 109 } 110 111 static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key, 112 unsigned int keylen) 113 { 114 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(tfm)); 115 116 if (keylen != GHASH_BLOCK_SIZE) 117 return -EINVAL; 118 119 preempt_disable(); 120 pagefault_disable(); 121 enable_kernel_vsx(); 122 gcm_init_p8(ctx->htable, (const u64 *) key); 123 disable_kernel_vsx(); 124 pagefault_enable(); 125 preempt_enable(); 126 return crypto_shash_setkey(ctx->fallback, key, keylen); 127 } 128 129 static int p8_ghash_update(struct shash_desc *desc, 130 const u8 *src, unsigned int srclen) 131 { 132 unsigned int len; 133 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm)); 134 struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc); 135 136 if (IN_INTERRUPT) { 137 return crypto_shash_update(&dctx->fallback_desc, src, 138 srclen); 139 } else { 140 if (dctx->bytes) { 141 if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) { 142 memcpy(dctx->buffer + dctx->bytes, src, 143 srclen); 144 dctx->bytes += srclen; 145 return 0; 146 } 147 memcpy(dctx->buffer + dctx->bytes, src, 148 GHASH_DIGEST_SIZE - dctx->bytes); 149 preempt_disable(); 150 pagefault_disable(); 151 enable_kernel_vsx(); 152 gcm_ghash_p8(dctx->shash, ctx->htable, 153 dctx->buffer, GHASH_DIGEST_SIZE); 154 disable_kernel_vsx(); 155 pagefault_enable(); 156 preempt_enable(); 157 src += GHASH_DIGEST_SIZE - dctx->bytes; 158 srclen -= GHASH_DIGEST_SIZE - dctx->bytes; 159 dctx->bytes = 0; 160 } 161 len = srclen & ~(GHASH_DIGEST_SIZE - 1); 162 if (len) { 163 preempt_disable(); 164 pagefault_disable(); 165 enable_kernel_vsx(); 166 gcm_ghash_p8(dctx->shash, ctx->htable, src, len); 167 disable_kernel_vsx(); 168 pagefault_enable(); 169 preempt_enable(); 170 src += len; 171 srclen -= len; 172 } 173 if (srclen) { 174 memcpy(dctx->buffer, src, srclen); 175 dctx->bytes = srclen; 176 } 177 return 0; 178 } 179 } 180 181 static int p8_ghash_final(struct shash_desc *desc, u8 *out) 182 { 183 int i; 184 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm)); 185 struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc); 186 187 if (IN_INTERRUPT) { 188 return crypto_shash_final(&dctx->fallback_desc, out); 189 } else { 190 if (dctx->bytes) { 191 for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++) 192 dctx->buffer[i] = 0; 193 preempt_disable(); 194 pagefault_disable(); 195 enable_kernel_vsx(); 196 gcm_ghash_p8(dctx->shash, ctx->htable, 197 dctx->buffer, GHASH_DIGEST_SIZE); 198 disable_kernel_vsx(); 199 pagefault_enable(); 200 preempt_enable(); 201 dctx->bytes = 0; 202 } 203 memcpy(out, dctx->shash, GHASH_DIGEST_SIZE); 204 return 0; 205 } 206 } 207 208 struct shash_alg p8_ghash_alg = { 209 .digestsize = GHASH_DIGEST_SIZE, 210 .init = p8_ghash_init, 211 .update = p8_ghash_update, 212 .final = p8_ghash_final, 213 .setkey = p8_ghash_setkey, 214 .descsize = sizeof(struct p8_ghash_desc_ctx) 215 + sizeof(struct ghash_desc_ctx), 216 .base = { 217 .cra_name = "ghash", 218 .cra_driver_name = "p8_ghash", 219 .cra_priority = 1000, 220 .cra_flags = CRYPTO_ALG_TYPE_SHASH | CRYPTO_ALG_NEED_FALLBACK, 221 .cra_blocksize = GHASH_BLOCK_SIZE, 222 .cra_ctxsize = sizeof(struct p8_ghash_ctx), 223 .cra_module = THIS_MODULE, 224 .cra_init = p8_ghash_init_tfm, 225 .cra_exit = p8_ghash_exit_tfm, 226 }, 227 }; 228