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8ff59090 HX |
1 | /* |
2 | * algif_skcipher: User-space interface for skcipher algorithms | |
3 | * | |
4 | * This file provides the user-space API for symmetric key ciphers. | |
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 | * | |
e870456d SM |
13 | * The following concept of the memory management is used: |
14 | * | |
15 | * The kernel maintains two SGLs, the TX SGL and the RX SGL. The TX SGL is | |
16 | * filled by user space with the data submitted via sendpage/sendmsg. Filling | |
17 | * up the TX SGL does not cause a crypto operation -- the data will only be | |
18 | * tracked by the kernel. Upon receipt of one recvmsg call, the caller must | |
19 | * provide a buffer which is tracked with the RX SGL. | |
20 | * | |
21 | * During the processing of the recvmsg operation, the cipher request is | |
22 | * allocated and prepared. As part of the recvmsg operation, the processed | |
23 | * TX buffers are extracted from the TX SGL into a separate SGL. | |
24 | * | |
25 | * After the completion of the crypto operation, the RX SGL and the cipher | |
26 | * request is released. The extracted TX SGL parts are released together with | |
27 | * the RX SGL release. | |
8ff59090 HX |
28 | */ |
29 | ||
30 | #include <crypto/scatterwalk.h> | |
31 | #include <crypto/skcipher.h> | |
32 | #include <crypto/if_alg.h> | |
33 | #include <linux/init.h> | |
34 | #include <linux/list.h> | |
35 | #include <linux/kernel.h> | |
36 | #include <linux/mm.h> | |
37 | #include <linux/module.h> | |
38 | #include <linux/net.h> | |
39 | #include <net/sock.h> | |
40 | ||
dd504589 HX |
41 | struct skcipher_tfm { |
42 | struct crypto_skcipher *skcipher; | |
43 | bool has_key; | |
44 | }; | |
45 | ||
1b784140 YX |
46 | static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg, |
47 | size_t size) | |
8ff59090 HX |
48 | { |
49 | struct sock *sk = sock->sk; | |
50 | struct alg_sock *ask = alg_sk(sk); | |
6454c2b8 HX |
51 | struct sock *psk = ask->parent; |
52 | struct alg_sock *pask = alg_sk(psk); | |
6454c2b8 HX |
53 | struct skcipher_tfm *skc = pask->private; |
54 | struct crypto_skcipher *tfm = skc->skcipher; | |
0d96e4ba | 55 | unsigned ivsize = crypto_skcipher_ivsize(tfm); |
8ff59090 | 56 | |
2d97591e | 57 | return af_alg_sendmsg(sock, msg, size, ivsize); |
a596999b TS |
58 | } |
59 | ||
e870456d SM |
60 | static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg, |
61 | size_t ignored, int flags) | |
a596999b TS |
62 | { |
63 | struct sock *sk = sock->sk; | |
64 | struct alg_sock *ask = alg_sk(sk); | |
ec69bbfb HX |
65 | struct sock *psk = ask->parent; |
66 | struct alg_sock *pask = alg_sk(psk); | |
2d97591e | 67 | struct af_alg_ctx *ctx = ask->private; |
ec69bbfb HX |
68 | struct skcipher_tfm *skc = pask->private; |
69 | struct crypto_skcipher *tfm = skc->skcipher; | |
e870456d | 70 | unsigned int bs = crypto_skcipher_blocksize(tfm); |
2d97591e | 71 | struct af_alg_async_req *areq; |
e870456d SM |
72 | int err = 0; |
73 | size_t len = 0; | |
ec69bbfb | 74 | |
11edb555 SM |
75 | if (!ctx->used) { |
76 | err = af_alg_wait_for_data(sk, flags); | |
77 | if (err) | |
78 | return err; | |
79 | } | |
80 | ||
e870456d | 81 | /* Allocate cipher request for current operation. */ |
2d97591e SM |
82 | areq = af_alg_alloc_areq(sk, sizeof(struct af_alg_async_req) + |
83 | crypto_skcipher_reqsize(tfm)); | |
84 | if (IS_ERR(areq)) | |
85 | return PTR_ERR(areq); | |
a596999b | 86 | |
e870456d | 87 | /* convert iovecs of output buffers into RX SGL */ |
2d97591e SM |
88 | err = af_alg_get_rsgl(sk, msg, flags, areq, -1, &len); |
89 | if (err) | |
90 | goto free; | |
a596999b | 91 | |
e870456d SM |
92 | /* Process only as much RX buffers for which we have TX data */ |
93 | if (len > ctx->used) | |
94 | len = ctx->used; | |
95 | ||
96 | /* | |
97 | * If more buffers are to be expected to be processed, process only | |
98 | * full block size buffers. | |
99 | */ | |
100 | if (ctx->more || len < ctx->used) | |
101 | len -= len % bs; | |
102 | ||
103 | /* | |
104 | * Create a per request TX SGL for this request which tracks the | |
105 | * SG entries from the global TX SGL. | |
106 | */ | |
2d97591e | 107 | areq->tsgl_entries = af_alg_count_tsgl(sk, len, 0); |
e870456d SM |
108 | if (!areq->tsgl_entries) |
109 | areq->tsgl_entries = 1; | |
110 | areq->tsgl = sock_kmalloc(sk, sizeof(*areq->tsgl) * areq->tsgl_entries, | |
111 | GFP_KERNEL); | |
112 | if (!areq->tsgl) { | |
113 | err = -ENOMEM; | |
114 | goto free; | |
115 | } | |
116 | sg_init_table(areq->tsgl, areq->tsgl_entries); | |
2d97591e | 117 | af_alg_pull_tsgl(sk, len, areq->tsgl, 0); |
e870456d SM |
118 | |
119 | /* Initialize the crypto operation */ | |
2d97591e SM |
120 | skcipher_request_set_tfm(&areq->cra_u.skcipher_req, tfm); |
121 | skcipher_request_set_crypt(&areq->cra_u.skcipher_req, areq->tsgl, | |
122 | areq->first_rsgl.sgl.sg, len, ctx->iv); | |
e870456d SM |
123 | |
124 | if (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) { | |
125 | /* AIO operation */ | |
7d2c3f54 | 126 | sock_hold(sk); |
e870456d | 127 | areq->iocb = msg->msg_iocb; |
d53c5135 SM |
128 | |
129 | /* Remember output size that will be generated. */ | |
130 | areq->outlen = len; | |
131 | ||
2d97591e | 132 | skcipher_request_set_callback(&areq->cra_u.skcipher_req, |
e870456d | 133 | CRYPTO_TFM_REQ_MAY_SLEEP, |
2d97591e SM |
134 | af_alg_async_cb, areq); |
135 | err = ctx->enc ? | |
136 | crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) : | |
137 | crypto_skcipher_decrypt(&areq->cra_u.skcipher_req); | |
7d2c3f54 SM |
138 | |
139 | /* AIO operation in progress */ | |
d53c5135 | 140 | if (err == -EINPROGRESS || err == -EBUSY) |
7d2c3f54 | 141 | return -EIOCBQUEUED; |
7d2c3f54 SM |
142 | |
143 | sock_put(sk); | |
e870456d SM |
144 | } else { |
145 | /* Synchronous operation */ | |
2d97591e | 146 | skcipher_request_set_callback(&areq->cra_u.skcipher_req, |
e870456d SM |
147 | CRYPTO_TFM_REQ_MAY_SLEEP | |
148 | CRYPTO_TFM_REQ_MAY_BACKLOG, | |
2c3f8b16 GBY |
149 | crypto_req_done, &ctx->wait); |
150 | err = crypto_wait_req(ctx->enc ? | |
2d97591e SM |
151 | crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) : |
152 | crypto_skcipher_decrypt(&areq->cra_u.skcipher_req), | |
2c3f8b16 | 153 | &ctx->wait); |
e870456d | 154 | } |
033f46b3 | 155 | |
e870456d | 156 | |
a596999b | 157 | free: |
7d2c3f54 | 158 | af_alg_free_resources(areq); |
e870456d SM |
159 | |
160 | return err ? err : len; | |
a596999b TS |
161 | } |
162 | ||
e870456d SM |
163 | static int skcipher_recvmsg(struct socket *sock, struct msghdr *msg, |
164 | size_t ignored, int flags) | |
8ff59090 HX |
165 | { |
166 | struct sock *sk = sock->sk; | |
e870456d | 167 | int ret = 0; |
8ff59090 HX |
168 | |
169 | lock_sock(sk); | |
01e97e65 | 170 | while (msg_data_left(msg)) { |
e870456d SM |
171 | int err = _skcipher_recvmsg(sock, msg, ignored, flags); |
172 | ||
173 | /* | |
174 | * This error covers -EIOCBQUEUED which implies that we can | |
175 | * only handle one AIO request. If the caller wants to have | |
176 | * multiple AIO requests in parallel, he must make multiple | |
177 | * separate AIO calls. | |
5703c826 SM |
178 | * |
179 | * Also return the error if no data has been processed so far. | |
e870456d SM |
180 | */ |
181 | if (err <= 0) { | |
5703c826 | 182 | if (err == -EIOCBQUEUED || !ret) |
e870456d SM |
183 | ret = err; |
184 | goto out; | |
1d10eb2f AV |
185 | } |
186 | ||
e870456d | 187 | ret += err; |
8ff59090 HX |
188 | } |
189 | ||
e870456d | 190 | out: |
2d97591e | 191 | af_alg_wmem_wakeup(sk); |
8ff59090 | 192 | release_sock(sk); |
e870456d | 193 | return ret; |
a596999b | 194 | } |
8ff59090 | 195 | |
8ff59090 HX |
196 | |
197 | static struct proto_ops algif_skcipher_ops = { | |
198 | .family = PF_ALG, | |
199 | ||
200 | .connect = sock_no_connect, | |
201 | .socketpair = sock_no_socketpair, | |
202 | .getname = sock_no_getname, | |
203 | .ioctl = sock_no_ioctl, | |
204 | .listen = sock_no_listen, | |
205 | .shutdown = sock_no_shutdown, | |
206 | .getsockopt = sock_no_getsockopt, | |
207 | .mmap = sock_no_mmap, | |
208 | .bind = sock_no_bind, | |
209 | .accept = sock_no_accept, | |
210 | .setsockopt = sock_no_setsockopt, | |
211 | ||
212 | .release = af_alg_release, | |
213 | .sendmsg = skcipher_sendmsg, | |
2d97591e | 214 | .sendpage = af_alg_sendpage, |
8ff59090 | 215 | .recvmsg = skcipher_recvmsg, |
2d97591e | 216 | .poll = af_alg_poll, |
8ff59090 HX |
217 | }; |
218 | ||
a0fa2d03 HX |
219 | static int skcipher_check_key(struct socket *sock) |
220 | { | |
1822793a | 221 | int err = 0; |
a0fa2d03 HX |
222 | struct sock *psk; |
223 | struct alg_sock *pask; | |
224 | struct skcipher_tfm *tfm; | |
225 | struct sock *sk = sock->sk; | |
226 | struct alg_sock *ask = alg_sk(sk); | |
227 | ||
1822793a | 228 | lock_sock(sk); |
a0fa2d03 | 229 | if (ask->refcnt) |
1822793a | 230 | goto unlock_child; |
a0fa2d03 HX |
231 | |
232 | psk = ask->parent; | |
233 | pask = alg_sk(ask->parent); | |
234 | tfm = pask->private; | |
235 | ||
236 | err = -ENOKEY; | |
1822793a | 237 | lock_sock_nested(psk, SINGLE_DEPTH_NESTING); |
a0fa2d03 HX |
238 | if (!tfm->has_key) |
239 | goto unlock; | |
240 | ||
241 | if (!pask->refcnt++) | |
242 | sock_hold(psk); | |
243 | ||
244 | ask->refcnt = 1; | |
245 | sock_put(psk); | |
246 | ||
247 | err = 0; | |
248 | ||
249 | unlock: | |
250 | release_sock(psk); | |
1822793a HX |
251 | unlock_child: |
252 | release_sock(sk); | |
a0fa2d03 HX |
253 | |
254 | return err; | |
255 | } | |
256 | ||
257 | static int skcipher_sendmsg_nokey(struct socket *sock, struct msghdr *msg, | |
258 | size_t size) | |
259 | { | |
260 | int err; | |
261 | ||
262 | err = skcipher_check_key(sock); | |
263 | if (err) | |
264 | return err; | |
265 | ||
266 | return skcipher_sendmsg(sock, msg, size); | |
267 | } | |
268 | ||
269 | static ssize_t skcipher_sendpage_nokey(struct socket *sock, struct page *page, | |
270 | int offset, size_t size, int flags) | |
271 | { | |
272 | int err; | |
273 | ||
274 | err = skcipher_check_key(sock); | |
275 | if (err) | |
276 | return err; | |
277 | ||
2d97591e | 278 | return af_alg_sendpage(sock, page, offset, size, flags); |
a0fa2d03 HX |
279 | } |
280 | ||
281 | static int skcipher_recvmsg_nokey(struct socket *sock, struct msghdr *msg, | |
282 | size_t ignored, int flags) | |
283 | { | |
284 | int err; | |
285 | ||
286 | err = skcipher_check_key(sock); | |
287 | if (err) | |
288 | return err; | |
289 | ||
290 | return skcipher_recvmsg(sock, msg, ignored, flags); | |
291 | } | |
292 | ||
293 | static struct proto_ops algif_skcipher_ops_nokey = { | |
294 | .family = PF_ALG, | |
295 | ||
296 | .connect = sock_no_connect, | |
297 | .socketpair = sock_no_socketpair, | |
298 | .getname = sock_no_getname, | |
299 | .ioctl = sock_no_ioctl, | |
300 | .listen = sock_no_listen, | |
301 | .shutdown = sock_no_shutdown, | |
302 | .getsockopt = sock_no_getsockopt, | |
303 | .mmap = sock_no_mmap, | |
304 | .bind = sock_no_bind, | |
305 | .accept = sock_no_accept, | |
306 | .setsockopt = sock_no_setsockopt, | |
307 | ||
308 | .release = af_alg_release, | |
309 | .sendmsg = skcipher_sendmsg_nokey, | |
310 | .sendpage = skcipher_sendpage_nokey, | |
311 | .recvmsg = skcipher_recvmsg_nokey, | |
2d97591e | 312 | .poll = af_alg_poll, |
a0fa2d03 HX |
313 | }; |
314 | ||
8ff59090 HX |
315 | static void *skcipher_bind(const char *name, u32 type, u32 mask) |
316 | { | |
dd504589 HX |
317 | struct skcipher_tfm *tfm; |
318 | struct crypto_skcipher *skcipher; | |
319 | ||
320 | tfm = kzalloc(sizeof(*tfm), GFP_KERNEL); | |
321 | if (!tfm) | |
322 | return ERR_PTR(-ENOMEM); | |
323 | ||
324 | skcipher = crypto_alloc_skcipher(name, type, mask); | |
325 | if (IS_ERR(skcipher)) { | |
326 | kfree(tfm); | |
327 | return ERR_CAST(skcipher); | |
328 | } | |
329 | ||
330 | tfm->skcipher = skcipher; | |
331 | ||
332 | return tfm; | |
8ff59090 HX |
333 | } |
334 | ||
335 | static void skcipher_release(void *private) | |
336 | { | |
dd504589 HX |
337 | struct skcipher_tfm *tfm = private; |
338 | ||
339 | crypto_free_skcipher(tfm->skcipher); | |
340 | kfree(tfm); | |
8ff59090 HX |
341 | } |
342 | ||
343 | static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen) | |
344 | { | |
dd504589 HX |
345 | struct skcipher_tfm *tfm = private; |
346 | int err; | |
347 | ||
348 | err = crypto_skcipher_setkey(tfm->skcipher, key, keylen); | |
349 | tfm->has_key = !err; | |
350 | ||
351 | return err; | |
8ff59090 HX |
352 | } |
353 | ||
354 | static void skcipher_sock_destruct(struct sock *sk) | |
355 | { | |
356 | struct alg_sock *ask = alg_sk(sk); | |
2d97591e | 357 | struct af_alg_ctx *ctx = ask->private; |
e870456d SM |
358 | struct sock *psk = ask->parent; |
359 | struct alg_sock *pask = alg_sk(psk); | |
360 | struct skcipher_tfm *skc = pask->private; | |
361 | struct crypto_skcipher *tfm = skc->skcipher; | |
a596999b | 362 | |
2d97591e | 363 | af_alg_pull_tsgl(sk, ctx->used, NULL, 0); |
0d96e4ba | 364 | sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm)); |
8ff59090 HX |
365 | sock_kfree_s(sk, ctx, ctx->len); |
366 | af_alg_release_parent(sk); | |
367 | } | |
368 | ||
d7b65aee | 369 | static int skcipher_accept_parent_nokey(void *private, struct sock *sk) |
8ff59090 | 370 | { |
2d97591e | 371 | struct af_alg_ctx *ctx; |
8ff59090 | 372 | struct alg_sock *ask = alg_sk(sk); |
dd504589 HX |
373 | struct skcipher_tfm *tfm = private; |
374 | struct crypto_skcipher *skcipher = tfm->skcipher; | |
e870456d | 375 | unsigned int len = sizeof(*ctx); |
8ff59090 HX |
376 | |
377 | ctx = sock_kmalloc(sk, len, GFP_KERNEL); | |
378 | if (!ctx) | |
379 | return -ENOMEM; | |
380 | ||
dd504589 | 381 | ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(skcipher), |
8ff59090 HX |
382 | GFP_KERNEL); |
383 | if (!ctx->iv) { | |
384 | sock_kfree_s(sk, ctx, len); | |
385 | return -ENOMEM; | |
386 | } | |
387 | ||
dd504589 | 388 | memset(ctx->iv, 0, crypto_skcipher_ivsize(skcipher)); |
8ff59090 | 389 | |
e870456d | 390 | INIT_LIST_HEAD(&ctx->tsgl_list); |
8ff59090 HX |
391 | ctx->len = len; |
392 | ctx->used = 0; | |
e870456d | 393 | ctx->rcvused = 0; |
8ff59090 HX |
394 | ctx->more = 0; |
395 | ctx->merge = 0; | |
396 | ctx->enc = 0; | |
2c3f8b16 | 397 | crypto_init_wait(&ctx->wait); |
8ff59090 HX |
398 | |
399 | ask->private = ctx; | |
400 | ||
8ff59090 HX |
401 | sk->sk_destruct = skcipher_sock_destruct; |
402 | ||
403 | return 0; | |
404 | } | |
405 | ||
a0fa2d03 HX |
406 | static int skcipher_accept_parent(void *private, struct sock *sk) |
407 | { | |
408 | struct skcipher_tfm *tfm = private; | |
409 | ||
6e8d8ecf | 410 | if (!tfm->has_key && crypto_skcipher_has_setkey(tfm->skcipher)) |
a0fa2d03 HX |
411 | return -ENOKEY; |
412 | ||
d7b65aee | 413 | return skcipher_accept_parent_nokey(private, sk); |
a0fa2d03 HX |
414 | } |
415 | ||
8ff59090 HX |
416 | static const struct af_alg_type algif_type_skcipher = { |
417 | .bind = skcipher_bind, | |
418 | .release = skcipher_release, | |
419 | .setkey = skcipher_setkey, | |
420 | .accept = skcipher_accept_parent, | |
a0fa2d03 | 421 | .accept_nokey = skcipher_accept_parent_nokey, |
8ff59090 | 422 | .ops = &algif_skcipher_ops, |
a0fa2d03 | 423 | .ops_nokey = &algif_skcipher_ops_nokey, |
8ff59090 HX |
424 | .name = "skcipher", |
425 | .owner = THIS_MODULE | |
426 | }; | |
427 | ||
428 | static int __init algif_skcipher_init(void) | |
429 | { | |
430 | return af_alg_register_type(&algif_type_skcipher); | |
431 | } | |
432 | ||
433 | static void __exit algif_skcipher_exit(void) | |
434 | { | |
435 | int err = af_alg_unregister_type(&algif_type_skcipher); | |
436 | BUG_ON(err); | |
437 | } | |
438 | ||
439 | module_init(algif_skcipher_init); | |
440 | module_exit(algif_skcipher_exit); | |
441 | MODULE_LICENSE("GPL"); |