crypto/cryptd.c

   1 /*
   2  * Software async crypto daemon.
   3  *
   4  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  *
  11  */
  12
  13 #include <crypto/algapi.h>
  14 #include <linux/err.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/kthread.h>
  18 #include <linux/list.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/scatterlist.h>
  22 #include <linux/sched.h>
  23 #include <linux/slab.h>
  24 #include <linux/spinlock.h>
  25
  26 #define CRYPTD_MAX_QLEN 100
  27
  28 struct cryptd_state {
  29         spinlock_t lock;
  30         struct mutex mutex;
  31         struct crypto_queue queue;
  32         struct task_struct *task;
  33 };
  34
  35 struct cryptd_instance_ctx {
  36         struct crypto_spawn spawn;
  37         struct cryptd_state *state;
  38 };
  39
  40 struct cryptd_blkcipher_ctx {
  41         struct crypto_blkcipher *child;
  42 };
  43
  44 struct cryptd_blkcipher_request_ctx {
  45         crypto_completion_t complete;
  46 };
  47
  48
  49 static inline struct cryptd_state *cryptd_get_state(struct crypto_tfm *tfm)
  50 {
  51         struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
  52         struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
  53         return ictx->state;
  54 }
  55
  56 static int cryptd_blkcipher_setkey(struct crypto_ablkcipher *parent,
  57                                    const u8 *key, unsigned int keylen)
  58 {
  59         struct cryptd_blkcipher_ctx *ctx = crypto_ablkcipher_ctx(parent);
  60         struct crypto_blkcipher *child = ctx->child;
  61         int err;
  62
  63         crypto_blkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  64         crypto_blkcipher_set_flags(child, crypto_ablkcipher_get_flags(parent) &
  65                                           CRYPTO_TFM_REQ_MASK);
  66         err = crypto_blkcipher_setkey(child, key, keylen);
  67         crypto_ablkcipher_set_flags(parent, crypto_blkcipher_get_flags(child) &
  68                                             CRYPTO_TFM_RES_MASK);
  69         return err;
  70 }
  71
  72 static void cryptd_blkcipher_crypt(struct ablkcipher_request *req,
  73                                    struct crypto_blkcipher *child,
  74                                    int err,
  75                                    int (*crypt)(struct blkcipher_desc *desc,
  76                                                 struct scatterlist *dst,
  77                                                 struct scatterlist *src,
  78                                                 unsigned int len))
  79 {
  80         struct cryptd_blkcipher_request_ctx *rctx;
  81         struct blkcipher_desc desc;
  82
  83         rctx = ablkcipher_request_ctx(req);
  84
  85         if (unlikely(err == -EINPROGRESS)) {
  86                 rctx->complete(&req->base, err);
  87                 return;
  88         }
  89
  90         desc.tfm = child;
  91         desc.info = req->info;
  92         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
  93
  94         err = crypt(&desc, req->dst, req->src, req->nbytes);
  95
  96         req->base.complete = rctx->complete;
  97
  98         local_bh_disable();
  99         req->base.complete(&req->base, err);
 100         local_bh_enable();
 101 }
 102
 103 static void cryptd_blkcipher_encrypt(struct crypto_async_request *req, int err)
 104 {
 105         struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
 106         struct crypto_blkcipher *child = ctx->child;
 107
 108         cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
 109                                crypto_blkcipher_crt(child)->encrypt);
 110 }
 111
 112 static void cryptd_blkcipher_decrypt(struct crypto_async_request *req, int err)
 113 {
 114         struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(req->tfm);
 115         struct crypto_blkcipher *child = ctx->child;
 116
 117         cryptd_blkcipher_crypt(ablkcipher_request_cast(req), child, err,
 118                                crypto_blkcipher_crt(child)->decrypt);
 119 }
 120
 121 static int cryptd_blkcipher_enqueue(struct ablkcipher_request *req,
 122                                     crypto_completion_t complete)
 123 {
 124         struct cryptd_blkcipher_request_ctx *rctx = ablkcipher_request_ctx(req);
 125         struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
 126         struct cryptd_state *state =
 127                 cryptd_get_state(crypto_ablkcipher_tfm(tfm));
 128         int err;
 129
 130         rctx->complete = req->base.complete;
 131         req->base.complete = complete;
 132
 133         spin_lock_bh(&state->lock);
 134         err = ablkcipher_enqueue_request(&state->queue, req);
 135         spin_unlock_bh(&state->lock);
 136
 137         wake_up_process(state->task);
 138         return err;
 139 }
 140
 141 static int cryptd_blkcipher_encrypt_enqueue(struct ablkcipher_request *req)
 142 {
 143         return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_encrypt);
 144 }
 145
 146 static int cryptd_blkcipher_decrypt_enqueue(struct ablkcipher_request *req)
 147 {
 148         return cryptd_blkcipher_enqueue(req, cryptd_blkcipher_decrypt);
 149 }
 150
 151 static int cryptd_blkcipher_init_tfm(struct crypto_tfm *tfm)
 152 {
 153         struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
 154         struct cryptd_instance_ctx *ictx = crypto_instance_ctx(inst);
 155         struct crypto_spawn *spawn = &ictx->spawn;
 156         struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
 157         struct crypto_blkcipher *cipher;
 158
 159         cipher = crypto_spawn_blkcipher(spawn);
 160         if (IS_ERR(cipher))
 161                 return PTR_ERR(cipher);
 162
 163         ctx->child = cipher;
 164         tfm->crt_ablkcipher.reqsize =
 165                 sizeof(struct cryptd_blkcipher_request_ctx);
 166         return 0;
 167 }
 168
 169 static void cryptd_blkcipher_exit_tfm(struct crypto_tfm *tfm)
 170 {
 171         struct cryptd_blkcipher_ctx *ctx = crypto_tfm_ctx(tfm);
 172         struct cryptd_state *state = cryptd_get_state(tfm);
 173         int active;
 174
 175         mutex_lock(&state->mutex);
 176         active = ablkcipher_tfm_in_queue(&state->queue,
 177                                          __crypto_ablkcipher_cast(tfm));
 178         mutex_unlock(&state->mutex);
 179
 180         BUG_ON(active);
 181
 182         crypto_free_blkcipher(ctx->child);
 183 }
 184
 185 static struct crypto_instance *cryptd_alloc_instance(struct crypto_alg *alg,
 186                                                      struct cryptd_state *state)
 187 {
 188         struct crypto_instance *inst;
 189         struct cryptd_instance_ctx *ctx;
 190         int err;
 191
 192         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 193         if (IS_ERR(inst))
 194                 goto out;
 195
 196         err = -ENAMETOOLONG;
 197         if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 198                      "cryptd(%s)", alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 199                 goto out_free_inst;
 200
 201         ctx = crypto_instance_ctx(inst);
 202         err = crypto_init_spawn(&ctx->spawn, alg, inst,
 203                                 CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
 204         if (err)
 205                 goto out_free_inst;
 206
 207         ctx->state = state;
 208
 209         memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
 210
 211         inst->alg.cra_priority = alg->cra_priority + 50;
 212         inst->alg.cra_blocksize = alg->cra_blocksize;
 213         inst->alg.cra_alignmask = alg->cra_alignmask;
 214
 215 out:
 216         return inst;
 217
 218 out_free_inst:
 219         kfree(inst);
 220         inst = ERR_PTR(err);
 221         goto out;
 222 }
 223
 224 static struct crypto_instance *cryptd_alloc_blkcipher(
 225         struct rtattr **tb, struct cryptd_state *state)
 226 {
 227         struct crypto_instance *inst;
 228         struct crypto_alg *alg;
 229
 230         alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_BLKCIPHER,
 231                                   CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
 232         if (IS_ERR(alg))
 233                 return ERR_PTR(PTR_ERR(alg));
 234
 235         inst = cryptd_alloc_instance(alg, state);
 236         if (IS_ERR(inst))
 237                 goto out_put_alg;
 238
 239         inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_ASYNC;
 240         inst->alg.cra_type = &crypto_ablkcipher_type;
 241
 242         inst->alg.cra_ablkcipher.ivsize = alg->cra_blkcipher.ivsize;
 243         inst->alg.cra_ablkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
 244         inst->alg.cra_ablkcipher.max_keysize = alg->cra_blkcipher.max_keysize;
 245
 246         inst->alg.cra_ctxsize = sizeof(struct cryptd_blkcipher_ctx);
 247
 248         inst->alg.cra_init = cryptd_blkcipher_init_tfm;
 249         inst->alg.cra_exit = cryptd_blkcipher_exit_tfm;
 250
 251         inst->alg.cra_ablkcipher.setkey = cryptd_blkcipher_setkey;
 252         inst->alg.cra_ablkcipher.encrypt = cryptd_blkcipher_encrypt_enqueue;
 253         inst->alg.cra_ablkcipher.decrypt = cryptd_blkcipher_decrypt_enqueue;
 254
 255 out_put_alg:
 256         crypto_mod_put(alg);
 257         return inst;
 258 }
 259
 260 static struct cryptd_state state;
 261
 262 static struct crypto_instance *cryptd_alloc(struct rtattr **tb)
 263 {
 264         struct crypto_attr_type *algt;
 265
 266         algt = crypto_get_attr_type(tb);
 267         if (IS_ERR(algt))
 268                 return ERR_PTR(PTR_ERR(algt));
 269
 270         switch (algt->type & algt->mask & CRYPTO_ALG_TYPE_MASK) {
 271         case CRYPTO_ALG_TYPE_BLKCIPHER:
 272                 return cryptd_alloc_blkcipher(tb, &state);
 273         }
 274
 275         return ERR_PTR(-EINVAL);
 276 }
 277
 278 static void cryptd_free(struct crypto_instance *inst)
 279 {
 280         struct cryptd_instance_ctx *ctx = crypto_instance_ctx(inst);
 281
 282         crypto_drop_spawn(&ctx->spawn);
 283         kfree(inst);
 284 }
 285
 286 static struct crypto_template cryptd_tmpl = {
 287         .name = "cryptd",
 288         .alloc = cryptd_alloc,
 289         .free = cryptd_free,
 290         .module = THIS_MODULE,
 291 };
 292
 293 static inline int cryptd_create_thread(struct cryptd_state *state,
 294                                        int (*fn)(void *data), const char *name)
 295 {
 296         spin_lock_init(&state->lock);
 297         mutex_init(&state->mutex);
 298         crypto_init_queue(&state->queue, CRYPTD_MAX_QLEN);
 299
 300         state->task = kthread_run(fn, state, name);
 301         if (IS_ERR(state->task))
 302                 return PTR_ERR(state->task);
 303
 304         return 0;
 305 }
 306
 307 static inline void cryptd_stop_thread(struct cryptd_state *state)
 308 {
 309         BUG_ON(state->queue.qlen);
 310         kthread_stop(state->task);
 311 }
 312
 313 static int cryptd_thread(void *data)
 314 {
 315         struct cryptd_state *state = data;
 316         int stop;
 317
 318         current->flags |= PF_NOFREEZE;
 319
 320         do {
 321                 struct crypto_async_request *req, *backlog;
 322
 323                 mutex_lock(&state->mutex);
 324                 __set_current_state(TASK_INTERRUPTIBLE);
 325
 326                 spin_lock_bh(&state->lock);
 327                 backlog = crypto_get_backlog(&state->queue);
 328                 req = crypto_dequeue_request(&state->queue);
 329                 spin_unlock_bh(&state->lock);
 330
 331                 stop = kthread_should_stop();
 332
 333                 if (stop || req) {
 334                         __set_current_state(TASK_RUNNING);
 335                         if (req) {
 336                                 if (backlog)
 337                                         backlog->complete(backlog,
 338                                                           -EINPROGRESS);
 339                                 req->complete(req, 0);
 340                         }
 341                 }
 342
 343                 mutex_unlock(&state->mutex);
 344
 345                 schedule();
 346         } while (!stop);
 347
 348         return 0;
 349 }
 350
 351 static int __init cryptd_init(void)
 352 {
 353         int err;
 354
 355         err = cryptd_create_thread(&state, cryptd_thread, "cryptd");
 356         if (err)
 357                 return err;
 358
 359         err = crypto_register_template(&cryptd_tmpl);
 360         if (err)
 361                 kthread_stop(state.task);
 362
 363         return err;
 364 }
 365
 366 static void __exit cryptd_exit(void)
 367 {
 368         cryptd_stop_thread(&state);
 369         crypto_unregister_template(&cryptd_tmpl);
 370 }
 371
 372 module_init(cryptd_init);
 373 module_exit(cryptd_exit);
 374
 375 MODULE_LICENSE("GPL");
 376 MODULE_DESCRIPTION("Software async crypto daemon");