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Linux/crypto/algif_hash.c

  1 /*
  2  * algif_hash: User-space interface for hash algorithms
  3  *
  4  * This file provides the user-space API for hash algorithms.
  5  *
  6  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
  7  *
  8  * This program is free software; you can redistribute it and/or modify it
  9  * under the terms of the GNU General Public License as published by the Free
 10  * Software Foundation; either version 2 of the License, or (at your option)
 11  * any later version.
 12  *
 13  */
 14 
 15 #include <crypto/hash.h>
 16 #include <crypto/if_alg.h>
 17 #include <linux/init.h>
 18 #include <linux/kernel.h>
 19 #include <linux/mm.h>
 20 #include <linux/module.h>
 21 #include <linux/net.h>
 22 #include <net/sock.h>
 23 
 24 struct hash_ctx {
 25         struct af_alg_sgl sgl;
 26 
 27         u8 *result;
 28 
 29         struct af_alg_completion completion;
 30 
 31         unsigned int len;
 32         bool more;
 33 
 34         struct ahash_request req;
 35 };
 36 
 37 struct algif_hash_tfm {
 38         struct crypto_ahash *hash;
 39         bool has_key;
 40 };
 41 
 42 static int hash_alloc_result(struct sock *sk, struct hash_ctx *ctx)
 43 {
 44         unsigned ds;
 45 
 46         if (ctx->result)
 47                 return 0;
 48 
 49         ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
 50 
 51         ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
 52         if (!ctx->result)
 53                 return -ENOMEM;
 54 
 55         memset(ctx->result, 0, ds);
 56 
 57         return 0;
 58 }
 59 
 60 static void hash_free_result(struct sock *sk, struct hash_ctx *ctx)
 61 {
 62         unsigned ds;
 63 
 64         if (!ctx->result)
 65                 return;
 66 
 67         ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
 68 
 69         sock_kzfree_s(sk, ctx->result, ds);
 70         ctx->result = NULL;
 71 }
 72 
 73 static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
 74                         size_t ignored)
 75 {
 76         int limit = ALG_MAX_PAGES * PAGE_SIZE;
 77         struct sock *sk = sock->sk;
 78         struct alg_sock *ask = alg_sk(sk);
 79         struct hash_ctx *ctx = ask->private;
 80         long copied = 0;
 81         int err;
 82 
 83         if (limit > sk->sk_sndbuf)
 84                 limit = sk->sk_sndbuf;
 85 
 86         lock_sock(sk);
 87         if (!ctx->more) {
 88                 if ((msg->msg_flags & MSG_MORE))
 89                         hash_free_result(sk, ctx);
 90 
 91                 err = af_alg_wait_for_completion(crypto_ahash_init(&ctx->req),
 92                                                 &ctx->completion);
 93                 if (err)
 94                         goto unlock;
 95         }
 96 
 97         ctx->more = 0;
 98 
 99         while (msg_data_left(msg)) {
100                 int len = msg_data_left(msg);
101 
102                 if (len > limit)
103                         len = limit;
104 
105                 len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len);
106                 if (len < 0) {
107                         err = copied ? 0 : len;
108                         goto unlock;
109                 }
110 
111                 ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len);
112 
113                 err = af_alg_wait_for_completion(crypto_ahash_update(&ctx->req),
114                                                  &ctx->completion);
115                 af_alg_free_sg(&ctx->sgl);
116                 if (err)
117                         goto unlock;
118 
119                 copied += len;
120                 iov_iter_advance(&msg->msg_iter, len);
121         }
122 
123         err = 0;
124 
125         ctx->more = msg->msg_flags & MSG_MORE;
126         if (!ctx->more) {
127                 err = hash_alloc_result(sk, ctx);
128                 if (err)
129                         goto unlock;
130 
131                 ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
132                 err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
133                                                  &ctx->completion);
134         }
135 
136 unlock:
137         release_sock(sk);
138 
139         return err ?: copied;
140 }
141 
142 static ssize_t hash_sendpage(struct socket *sock, struct page *page,
143                              int offset, size_t size, int flags)
144 {
145         struct sock *sk = sock->sk;
146         struct alg_sock *ask = alg_sk(sk);
147         struct hash_ctx *ctx = ask->private;
148         int err;
149 
150         if (flags & MSG_SENDPAGE_NOTLAST)
151                 flags |= MSG_MORE;
152 
153         lock_sock(sk);
154         sg_init_table(ctx->sgl.sg, 1);
155         sg_set_page(ctx->sgl.sg, page, size, offset);
156 
157         if (!(flags & MSG_MORE)) {
158                 err = hash_alloc_result(sk, ctx);
159                 if (err)
160                         goto unlock;
161         } else if (!ctx->more)
162                 hash_free_result(sk, ctx);
163 
164         ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);
165 
166         if (!(flags & MSG_MORE)) {
167                 if (ctx->more)
168                         err = crypto_ahash_finup(&ctx->req);
169                 else
170                         err = crypto_ahash_digest(&ctx->req);
171         } else {
172                 if (!ctx->more) {
173                         err = crypto_ahash_init(&ctx->req);
174                         err = af_alg_wait_for_completion(err, &ctx->completion);
175                         if (err)
176                                 goto unlock;
177                 }
178 
179                 err = crypto_ahash_update(&ctx->req);
180         }
181 
182         err = af_alg_wait_for_completion(err, &ctx->completion);
183         if (err)
184                 goto unlock;
185 
186         ctx->more = flags & MSG_MORE;
187 
188 unlock:
189         release_sock(sk);
190 
191         return err ?: size;
192 }
193 
194 static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
195                         int flags)
196 {
197         struct sock *sk = sock->sk;
198         struct alg_sock *ask = alg_sk(sk);
199         struct hash_ctx *ctx = ask->private;
200         unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
201         bool result;
202         int err;
203 
204         if (len > ds)
205                 len = ds;
206         else if (len < ds)
207                 msg->msg_flags |= MSG_TRUNC;
208 
209         lock_sock(sk);
210         result = ctx->result;
211         err = hash_alloc_result(sk, ctx);
212         if (err)
213                 goto unlock;
214 
215         ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
216 
217         if (!result && !ctx->more) {
218                 err = af_alg_wait_for_completion(
219                                 crypto_ahash_init(&ctx->req),
220                                 &ctx->completion);
221                 if (err)
222                         goto unlock;
223         }
224 
225         if (!result || ctx->more) {
226                 ctx->more = 0;
227                 err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
228                                                  &ctx->completion);
229                 if (err)
230                         goto unlock;
231         }
232 
233         err = memcpy_to_msg(msg, ctx->result, len);
234 
235 unlock:
236         hash_free_result(sk, ctx);
237         release_sock(sk);
238 
239         return err ?: len;
240 }
241 
242 static int hash_accept(struct socket *sock, struct socket *newsock, int flags)
243 {
244         struct sock *sk = sock->sk;
245         struct alg_sock *ask = alg_sk(sk);
246         struct hash_ctx *ctx = ask->private;
247         struct ahash_request *req = &ctx->req;
248         char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req))];
249         struct sock *sk2;
250         struct alg_sock *ask2;
251         struct hash_ctx *ctx2;
252         bool more;
253         int err;
254 
255         lock_sock(sk);
256         more = ctx->more;
257         err = more ? crypto_ahash_export(req, state) : 0;
258         release_sock(sk);
259 
260         if (err)
261                 return err;
262 
263         err = af_alg_accept(ask->parent, newsock);
264         if (err)
265                 return err;
266 
267         sk2 = newsock->sk;
268         ask2 = alg_sk(sk2);
269         ctx2 = ask2->private;
270         ctx2->more = more;
271 
272         if (!more)
273                 return err;
274 
275         err = crypto_ahash_import(&ctx2->req, state);
276         if (err) {
277                 sock_orphan(sk2);
278                 sock_put(sk2);
279         }
280 
281         return err;
282 }
283 
284 static struct proto_ops algif_hash_ops = {
285         .family         =       PF_ALG,
286 
287         .connect        =       sock_no_connect,
288         .socketpair     =       sock_no_socketpair,
289         .getname        =       sock_no_getname,
290         .ioctl          =       sock_no_ioctl,
291         .listen         =       sock_no_listen,
292         .shutdown       =       sock_no_shutdown,
293         .getsockopt     =       sock_no_getsockopt,
294         .mmap           =       sock_no_mmap,
295         .bind           =       sock_no_bind,
296         .setsockopt     =       sock_no_setsockopt,
297         .poll           =       sock_no_poll,
298 
299         .release        =       af_alg_release,
300         .sendmsg        =       hash_sendmsg,
301         .sendpage       =       hash_sendpage,
302         .recvmsg        =       hash_recvmsg,
303         .accept         =       hash_accept,
304 };
305 
306 static int hash_check_key(struct socket *sock)
307 {
308         int err = 0;
309         struct sock *psk;
310         struct alg_sock *pask;
311         struct algif_hash_tfm *tfm;
312         struct sock *sk = sock->sk;
313         struct alg_sock *ask = alg_sk(sk);
314 
315         lock_sock(sk);
316         if (ask->refcnt)
317                 goto unlock_child;
318 
319         psk = ask->parent;
320         pask = alg_sk(ask->parent);
321         tfm = pask->private;
322 
323         err = -ENOKEY;
324         lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
325         if (!tfm->has_key)
326                 goto unlock;
327 
328         if (!pask->refcnt++)
329                 sock_hold(psk);
330 
331         ask->refcnt = 1;
332         sock_put(psk);
333 
334         err = 0;
335 
336 unlock:
337         release_sock(psk);
338 unlock_child:
339         release_sock(sk);
340 
341         return err;
342 }
343 
344 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
345                               size_t size)
346 {
347         int err;
348 
349         err = hash_check_key(sock);
350         if (err)
351                 return err;
352 
353         return hash_sendmsg(sock, msg, size);
354 }
355 
356 static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page,
357                                    int offset, size_t size, int flags)
358 {
359         int err;
360 
361         err = hash_check_key(sock);
362         if (err)
363                 return err;
364 
365         return hash_sendpage(sock, page, offset, size, flags);
366 }
367 
368 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
369                               size_t ignored, int flags)
370 {
371         int err;
372 
373         err = hash_check_key(sock);
374         if (err)
375                 return err;
376 
377         return hash_recvmsg(sock, msg, ignored, flags);
378 }
379 
380 static int hash_accept_nokey(struct socket *sock, struct socket *newsock,
381                              int flags)
382 {
383         int err;
384 
385         err = hash_check_key(sock);
386         if (err)
387                 return err;
388 
389         return hash_accept(sock, newsock, flags);
390 }
391 
392 static struct proto_ops algif_hash_ops_nokey = {
393         .family         =       PF_ALG,
394 
395         .connect        =       sock_no_connect,
396         .socketpair     =       sock_no_socketpair,
397         .getname        =       sock_no_getname,
398         .ioctl          =       sock_no_ioctl,
399         .listen         =       sock_no_listen,
400         .shutdown       =       sock_no_shutdown,
401         .getsockopt     =       sock_no_getsockopt,
402         .mmap           =       sock_no_mmap,
403         .bind           =       sock_no_bind,
404         .setsockopt     =       sock_no_setsockopt,
405         .poll           =       sock_no_poll,
406 
407         .release        =       af_alg_release,
408         .sendmsg        =       hash_sendmsg_nokey,
409         .sendpage       =       hash_sendpage_nokey,
410         .recvmsg        =       hash_recvmsg_nokey,
411         .accept         =       hash_accept_nokey,
412 };
413 
414 static void *hash_bind(const char *name, u32 type, u32 mask)
415 {
416         struct algif_hash_tfm *tfm;
417         struct crypto_ahash *hash;
418 
419         tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
420         if (!tfm)
421                 return ERR_PTR(-ENOMEM);
422 
423         hash = crypto_alloc_ahash(name, type, mask);
424         if (IS_ERR(hash)) {
425                 kfree(tfm);
426                 return ERR_CAST(hash);
427         }
428 
429         tfm->hash = hash;
430 
431         return tfm;
432 }
433 
434 static void hash_release(void *private)
435 {
436         struct algif_hash_tfm *tfm = private;
437 
438         crypto_free_ahash(tfm->hash);
439         kfree(tfm);
440 }
441 
442 static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
443 {
444         struct algif_hash_tfm *tfm = private;
445         int err;
446 
447         err = crypto_ahash_setkey(tfm->hash, key, keylen);
448         tfm->has_key = !err;
449 
450         return err;
451 }
452 
453 static void hash_sock_destruct(struct sock *sk)
454 {
455         struct alg_sock *ask = alg_sk(sk);
456         struct hash_ctx *ctx = ask->private;
457 
458         hash_free_result(sk, ctx);
459         sock_kfree_s(sk, ctx, ctx->len);
460         af_alg_release_parent(sk);
461 }
462 
463 static int hash_accept_parent_nokey(void *private, struct sock *sk)
464 {
465         struct hash_ctx *ctx;
466         struct alg_sock *ask = alg_sk(sk);
467         struct algif_hash_tfm *tfm = private;
468         struct crypto_ahash *hash = tfm->hash;
469         unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash);
470 
471         ctx = sock_kmalloc(sk, len, GFP_KERNEL);
472         if (!ctx)
473                 return -ENOMEM;
474 
475         ctx->result = NULL;
476         ctx->len = len;
477         ctx->more = 0;
478         af_alg_init_completion(&ctx->completion);
479 
480         ask->private = ctx;
481 
482         ahash_request_set_tfm(&ctx->req, hash);
483         ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
484                                    af_alg_complete, &ctx->completion);
485 
486         sk->sk_destruct = hash_sock_destruct;
487 
488         return 0;
489 }
490 
491 static int hash_accept_parent(void *private, struct sock *sk)
492 {
493         struct algif_hash_tfm *tfm = private;
494 
495         if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash))
496                 return -ENOKEY;
497 
498         return hash_accept_parent_nokey(private, sk);
499 }
500 
501 static const struct af_alg_type algif_type_hash = {
502         .bind           =       hash_bind,
503         .release        =       hash_release,
504         .setkey         =       hash_setkey,
505         .accept         =       hash_accept_parent,
506         .accept_nokey   =       hash_accept_parent_nokey,
507         .ops            =       &algif_hash_ops,
508         .ops_nokey      =       &algif_hash_ops_nokey,
509         .name           =       "hash",
510         .owner          =       THIS_MODULE
511 };
512 
513 static int __init algif_hash_init(void)
514 {
515         return af_alg_register_type(&algif_type_hash);
516 }
517 
518 static void __exit algif_hash_exit(void)
519 {
520         int err = af_alg_unregister_type(&algif_type_hash);
521         BUG_ON(err);
522 }
523 
524 module_init(algif_hash_init);
525 module_exit(algif_hash_exit);
526 MODULE_LICENSE("GPL");
527 

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