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   1 /*
   2  * Cryptographic API.
   3  *
   4  * Support for VIA PadLock hardware crypto engine.
   5  *
   6  * Copyright (c) 2006  Michal Ludvig <michal@logix.cz>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  */
  14
  15 #include <crypto/internal/hash.h>
  16 #include <crypto/sha.h>
  17 #include <linux/err.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/errno.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/kernel.h>
  23 #include <linux/scatterlist.h>
  24 #include <asm/i387.h>
  25 #include "padlock.h"
  26
  27 #ifdef CONFIG_64BIT
  28 #define STACK_ALIGN 16
  29 #else
  30 #define STACK_ALIGN 4
  31 #endif
  32
  33 struct padlock_sha_desc {
  34         struct shash_desc fallback;
  35 };
  36
  37 struct padlock_sha_ctx {
  38         struct crypto_shash *fallback;
  39 };
  40
  41 static int padlock_sha_init(struct shash_desc *desc)
  42 {
  43         struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
  44         struct padlock_sha_ctx *ctx = crypto_shash_ctx(desc->tfm);
  45
  46         dctx->fallback.tfm = ctx->fallback;
  47         dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
  48         return crypto_shash_init(&dctx->fallback);
  49 }
  50
  51 static int padlock_sha_update(struct shash_desc *desc,
  52                               const u8 *data, unsigned int length)
  53 {
  54         struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
  55
  56         dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
  57         return crypto_shash_update(&dctx->fallback, data, length);
  58 }
  59
  60 static inline void padlock_output_block(uint32_t *src,
  61                         uint32_t *dst, size_t count)
  62 {
  63         while (count--)
  64                 *dst++ = swab32(*src++);
  65 }
  66
  67 static int padlock_sha1_finup(struct shash_desc *desc, const u8 *in,
  68                               unsigned int count, u8 *out)
  69 {
  70         /* We can't store directly to *out as it may be unaligned. */
  71         /* BTW Don't reduce the buffer size below 128 Bytes!
  72          *     PadLock microcode needs it that big. */
  73         char buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
  74                 ((aligned(STACK_ALIGN)));
  75         char *result = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
  76         struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
  77         struct sha1_state state;
  78         unsigned int space;
  79         unsigned int leftover;
  80         int ts_state;
  81         int err;
  82
  83         dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
  84         err = crypto_shash_export(&dctx->fallback, &state);
  85         if (err)
  86                 goto out;
  87
  88         if (state.count + count > ULONG_MAX)
  89                 return crypto_shash_finup(&dctx->fallback, in, count, out);
  90
  91         leftover = ((state.count - 1) & (SHA1_BLOCK_SIZE - 1)) + 1;
  92         space =  SHA1_BLOCK_SIZE - leftover;
  93         if (space) {
  94                 if (count > space) {
  95                         err = crypto_shash_update(&dctx->fallback, in, space) ?:
  96                               crypto_shash_export(&dctx->fallback, &state);
  97                         if (err)
  98                                 goto out;
  99                         count -= space;
 100                         in += space;
 101                 } else {
 102                         memcpy(state.buffer + leftover, in, count);
 103                         in = state.buffer;
 104                         count += leftover;
 105                         state.count &= ~(SHA1_BLOCK_SIZE - 1);
 106                 }
 107         }
 108
 109         memcpy(result, &state.state, SHA1_DIGEST_SIZE);
 110
 111         /* prevent taking the spurious DNA fault with padlock. */
 112         ts_state = irq_ts_save();
 113         asm volatile (".byte 0xf3,0x0f,0xa6,0xc8" /* rep xsha1 */
 114                       : \
 115                       : "c"((unsigned long)state.count + count), \
 116                         "a"((unsigned long)state.count), \
 117                         "S"(in), "D"(result));
 118         irq_ts_restore(ts_state);
 119
 120         padlock_output_block((uint32_t *)result, (uint32_t *)out, 5);
 121
 122 out:
 123         return err;
 124 }
 125
 126 static int padlock_sha1_final(struct shash_desc *desc, u8 *out)
 127 {
 128         u8 buf[4];
 129
 130         return padlock_sha1_finup(desc, buf, 0, out);
 131 }
 132
 133 static int padlock_sha256_finup(struct shash_desc *desc, const u8 *in,
 134                                 unsigned int count, u8 *out)
 135 {
 136         /* We can't store directly to *out as it may be unaligned. */
 137         /* BTW Don't reduce the buffer size below 128 Bytes!
 138          *     PadLock microcode needs it that big. */
 139         char buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
 140                 ((aligned(STACK_ALIGN)));
 141         char *result = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
 142         struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
 143         struct sha256_state state;
 144         unsigned int space;
 145         unsigned int leftover;
 146         int ts_state;
 147         int err;
 148
 149         dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
 150         err = crypto_shash_export(&dctx->fallback, &state);
 151         if (err)
 152                 goto out;
 153
 154         if (state.count + count > ULONG_MAX)
 155                 return crypto_shash_finup(&dctx->fallback, in, count, out);
 156
 157         leftover = ((state.count - 1) & (SHA256_BLOCK_SIZE - 1)) + 1;
 158         space =  SHA256_BLOCK_SIZE - leftover;
 159         if (space) {
 160                 if (count > space) {
 161                         err = crypto_shash_update(&dctx->fallback, in, space) ?:
 162                               crypto_shash_export(&dctx->fallback, &state);
 163                         if (err)
 164                                 goto out;
 165                         count -= space;
 166                         in += space;
 167                 } else {
 168                         memcpy(state.buf + leftover, in, count);
 169                         in = state.buf;
 170                         count += leftover;
 171                         state.count &= ~(SHA1_BLOCK_SIZE - 1);
 172                 }
 173         }
 174
 175         memcpy(result, &state.state, SHA256_DIGEST_SIZE);
 176
 177         /* prevent taking the spurious DNA fault with padlock. */
 178         ts_state = irq_ts_save();
 179         asm volatile (".byte 0xf3,0x0f,0xa6,0xd0" /* rep xsha256 */
 180                       : \
 181                       : "c"((unsigned long)state.count + count), \
 182                         "a"((unsigned long)state.count), \
 183                         "S"(in), "D"(result));
 184         irq_ts_restore(ts_state);
 185
 186         padlock_output_block((uint32_t *)result, (uint32_t *)out, 8);
 187
 188 out:
 189         return err;
 190 }
 191
 192 static int padlock_sha256_final(struct shash_desc *desc, u8 *out)
 193 {
 194         u8 buf[4];
 195
 196         return padlock_sha256_finup(desc, buf, 0, out);
 197 }
 198
 199 static int padlock_cra_init(struct crypto_tfm *tfm)
 200 {
 201         struct crypto_shash *hash = __crypto_shash_cast(tfm);
 202         const char *fallback_driver_name = tfm->__crt_alg->cra_name;
 203         struct padlock_sha_ctx *ctx = crypto_tfm_ctx(tfm);
 204         struct crypto_shash *fallback_tfm;
 205         int err = -ENOMEM;
 206
 207         /* Allocate a fallback and abort if it failed. */
 208         fallback_tfm = crypto_alloc_shash(fallback_driver_name, 0,
 209                                           CRYPTO_ALG_NEED_FALLBACK);
 210         if (IS_ERR(fallback_tfm)) {
 211                 printk(KERN_WARNING PFX "Fallback driver '%s' could not be loaded!\n",
 212                        fallback_driver_name);
 213                 err = PTR_ERR(fallback_tfm);
 214                 goto out;
 215         }
 216
 217         ctx->fallback = fallback_tfm;
 218         hash->descsize += crypto_shash_descsize(fallback_tfm);
 219         return 0;
 220
 221 out:
 222         return err;
 223 }
 224
 225 static void padlock_cra_exit(struct crypto_tfm *tfm)
 226 {
 227         struct padlock_sha_ctx *ctx = crypto_tfm_ctx(tfm);
 228
 229         crypto_free_shash(ctx->fallback);
 230 }
 231
 232 static struct shash_alg sha1_alg = {
 233         .digestsize     =       SHA1_DIGEST_SIZE,
 234         .init           =       padlock_sha_init,
 235         .update         =       padlock_sha_update,
 236         .finup          =       padlock_sha1_finup,
 237         .final          =       padlock_sha1_final,
 238         .descsize       =       sizeof(struct padlock_sha_desc),
 239         .base           =       {
 240                 .cra_name               =       "sha1",
 241                 .cra_driver_name        =       "sha1-padlock",
 242                 .cra_priority           =       PADLOCK_CRA_PRIORITY,
 243                 .cra_flags              =       CRYPTO_ALG_TYPE_SHASH |
 244                                                 CRYPTO_ALG_NEED_FALLBACK,
 245                 .cra_blocksize          =       SHA1_BLOCK_SIZE,
 246                 .cra_ctxsize            =       sizeof(struct padlock_sha_ctx),
 247                 .cra_module             =       THIS_MODULE,
 248                 .cra_init               =       padlock_cra_init,
 249                 .cra_exit               =       padlock_cra_exit,
 250         }
 251 };
 252
 253 static struct shash_alg sha256_alg = {
 254         .digestsize     =       SHA256_DIGEST_SIZE,
 255         .init           =       padlock_sha_init,
 256         .update         =       padlock_sha_update,
 257         .finup          =       padlock_sha256_finup,
 258         .final          =       padlock_sha256_final,
 259         .descsize       =       sizeof(struct padlock_sha_desc),
 260         .base           =       {
 261                 .cra_name               =       "sha256",
 262                 .cra_driver_name        =       "sha256-padlock",
 263                 .cra_priority           =       PADLOCK_CRA_PRIORITY,
 264                 .cra_flags              =       CRYPTO_ALG_TYPE_SHASH |
 265                                                 CRYPTO_ALG_NEED_FALLBACK,
 266                 .cra_blocksize          =       SHA256_BLOCK_SIZE,
 267                 .cra_ctxsize            =       sizeof(struct padlock_sha_ctx),
 268                 .cra_module             =       THIS_MODULE,
 269                 .cra_init               =       padlock_cra_init,
 270                 .cra_exit               =       padlock_cra_exit,
 271         }
 272 };
 273
 274 static int __init padlock_init(void)
 275 {
 276         int rc = -ENODEV;
 277
 278         if (!cpu_has_phe) {
 279                 printk(KERN_NOTICE PFX "VIA PadLock Hash Engine not detected.\n");
 280                 return -ENODEV;
 281         }
 282
 283         if (!cpu_has_phe_enabled) {
 284                 printk(KERN_NOTICE PFX "VIA PadLock detected, but not enabled. Hmm, strange...\n");
 285                 return -ENODEV;
 286         }
 287
 288         rc = crypto_register_shash(&sha1_alg);
 289         if (rc)
 290                 goto out;
 291
 292         rc = crypto_register_shash(&sha256_alg);
 293         if (rc)
 294                 goto out_unreg1;
 295
 296         printk(KERN_NOTICE PFX "Using VIA PadLock ACE for SHA1/SHA256 algorithms.\n");
 297
 298         return 0;
 299
 300 out_unreg1:
 301         crypto_unregister_shash(&sha1_alg);
 302 out:
 303         printk(KERN_ERR PFX "VIA PadLock SHA1/SHA256 initialization failed.\n");
 304         return rc;
 305 }
 306
 307 static void __exit padlock_fini(void)
 308 {
 309         crypto_unregister_shash(&sha1_alg);
 310         crypto_unregister_shash(&sha256_alg);
 311 }
 312
 313 module_init(padlock_init);
 314 module_exit(padlock_fini);
 315
 316 MODULE_DESCRIPTION("VIA PadLock SHA1/SHA256 algorithms support.");
 317 MODULE_LICENSE("GPL");
 318 MODULE_AUTHOR("Michal Ludvig");
 319
 320 MODULE_ALIAS("sha1-all");
 321 MODULE_ALIAS("sha256-all");
 322 MODULE_ALIAS("sha1-padlock");
 323 MODULE_ALIAS("sha256-padlock");