2 * algif_skcipher: User-space interface for skcipher algorithms
4 * This file provides the user-space API for symmetric key ciphers.
6 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
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)
13 * The following concept of the memory management is used:
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.
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.
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
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>
37 #include <linux/module.h>
38 #include <linux/net.h>
41 static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg,
44 struct sock *sk = sock->sk;
45 struct alg_sock *ask = alg_sk(sk);
46 struct sock *psk = ask->parent;
47 struct alg_sock *pask = alg_sk(psk);
48 struct crypto_skcipher *tfm = pask->private;
49 unsigned ivsize = crypto_skcipher_ivsize(tfm);
51 return af_alg_sendmsg(sock, msg, size, ivsize);
54 static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
55 size_t ignored, int flags)
57 struct sock *sk = sock->sk;
58 struct alg_sock *ask = alg_sk(sk);
59 struct sock *psk = ask->parent;
60 struct alg_sock *pask = alg_sk(psk);
61 struct af_alg_ctx *ctx = ask->private;
62 struct crypto_skcipher *tfm = pask->private;
63 unsigned int bs = crypto_skcipher_blocksize(tfm);
64 struct af_alg_async_req *areq;
69 err = af_alg_wait_for_data(sk, flags);
74 /* Allocate cipher request for current operation. */
75 areq = af_alg_alloc_areq(sk, sizeof(struct af_alg_async_req) +
76 crypto_skcipher_reqsize(tfm));
80 /* convert iovecs of output buffers into RX SGL */
81 err = af_alg_get_rsgl(sk, msg, flags, areq, ctx->used, &len);
86 * If more buffers are to be expected to be processed, process only
87 * full block size buffers.
89 if (ctx->more || len < ctx->used)
93 * Create a per request TX SGL for this request which tracks the
94 * SG entries from the global TX SGL.
96 areq->tsgl_entries = af_alg_count_tsgl(sk, len, 0);
97 if (!areq->tsgl_entries)
98 areq->tsgl_entries = 1;
99 areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl),
106 sg_init_table(areq->tsgl, areq->tsgl_entries);
107 af_alg_pull_tsgl(sk, len, areq->tsgl, 0);
109 /* Initialize the crypto operation */
110 skcipher_request_set_tfm(&areq->cra_u.skcipher_req, tfm);
111 skcipher_request_set_crypt(&areq->cra_u.skcipher_req, areq->tsgl,
112 areq->first_rsgl.sgl.sg, len, ctx->iv);
114 if (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) {
117 areq->iocb = msg->msg_iocb;
119 /* Remember output size that will be generated. */
122 skcipher_request_set_callback(&areq->cra_u.skcipher_req,
123 CRYPTO_TFM_REQ_MAY_SLEEP,
124 af_alg_async_cb, areq);
126 crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) :
127 crypto_skcipher_decrypt(&areq->cra_u.skcipher_req);
129 /* AIO operation in progress */
130 if (err == -EINPROGRESS)
135 /* Synchronous operation */
136 skcipher_request_set_callback(&areq->cra_u.skcipher_req,
137 CRYPTO_TFM_REQ_MAY_SLEEP |
138 CRYPTO_TFM_REQ_MAY_BACKLOG,
139 crypto_req_done, &ctx->wait);
140 err = crypto_wait_req(ctx->enc ?
141 crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) :
142 crypto_skcipher_decrypt(&areq->cra_u.skcipher_req),
148 af_alg_free_resources(areq);
150 return err ? err : len;
153 static int skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
154 size_t ignored, int flags)
156 struct sock *sk = sock->sk;
160 while (msg_data_left(msg)) {
161 int err = _skcipher_recvmsg(sock, msg, ignored, flags);
164 * This error covers -EIOCBQUEUED which implies that we can
165 * only handle one AIO request. If the caller wants to have
166 * multiple AIO requests in parallel, he must make multiple
167 * separate AIO calls.
169 * Also return the error if no data has been processed so far.
172 if (err == -EIOCBQUEUED || !ret)
181 af_alg_wmem_wakeup(sk);
186 static struct proto_ops algif_skcipher_ops = {
189 .connect = sock_no_connect,
190 .socketpair = sock_no_socketpair,
191 .getname = sock_no_getname,
192 .ioctl = sock_no_ioctl,
193 .listen = sock_no_listen,
194 .shutdown = sock_no_shutdown,
195 .getsockopt = sock_no_getsockopt,
196 .mmap = sock_no_mmap,
197 .bind = sock_no_bind,
198 .accept = sock_no_accept,
199 .setsockopt = sock_no_setsockopt,
201 .release = af_alg_release,
202 .sendmsg = skcipher_sendmsg,
203 .sendpage = af_alg_sendpage,
204 .recvmsg = skcipher_recvmsg,
208 static int skcipher_check_key(struct socket *sock)
212 struct alg_sock *pask;
213 struct crypto_skcipher *tfm;
214 struct sock *sk = sock->sk;
215 struct alg_sock *ask = alg_sk(sk);
218 if (!atomic_read(&ask->nokey_refcnt))
222 pask = alg_sk(ask->parent);
226 lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
227 if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
230 atomic_dec(&pask->nokey_refcnt);
231 atomic_set(&ask->nokey_refcnt, 0);
243 static int skcipher_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
248 err = skcipher_check_key(sock);
252 return skcipher_sendmsg(sock, msg, size);
255 static ssize_t skcipher_sendpage_nokey(struct socket *sock, struct page *page,
256 int offset, size_t size, int flags)
260 err = skcipher_check_key(sock);
264 return af_alg_sendpage(sock, page, offset, size, flags);
267 static int skcipher_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
268 size_t ignored, int flags)
272 err = skcipher_check_key(sock);
276 return skcipher_recvmsg(sock, msg, ignored, flags);
279 static struct proto_ops algif_skcipher_ops_nokey = {
282 .connect = sock_no_connect,
283 .socketpair = sock_no_socketpair,
284 .getname = sock_no_getname,
285 .ioctl = sock_no_ioctl,
286 .listen = sock_no_listen,
287 .shutdown = sock_no_shutdown,
288 .getsockopt = sock_no_getsockopt,
289 .mmap = sock_no_mmap,
290 .bind = sock_no_bind,
291 .accept = sock_no_accept,
292 .setsockopt = sock_no_setsockopt,
294 .release = af_alg_release,
295 .sendmsg = skcipher_sendmsg_nokey,
296 .sendpage = skcipher_sendpage_nokey,
297 .recvmsg = skcipher_recvmsg_nokey,
301 static void *skcipher_bind(const char *name, u32 type, u32 mask)
303 return crypto_alloc_skcipher(name, type, mask);
306 static void skcipher_release(void *private)
308 crypto_free_skcipher(private);
311 static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
313 return crypto_skcipher_setkey(private, key, keylen);
316 static void skcipher_sock_destruct(struct sock *sk)
318 struct alg_sock *ask = alg_sk(sk);
319 struct af_alg_ctx *ctx = ask->private;
320 struct sock *psk = ask->parent;
321 struct alg_sock *pask = alg_sk(psk);
322 struct crypto_skcipher *tfm = pask->private;
324 af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
325 sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm));
326 sock_kfree_s(sk, ctx, ctx->len);
327 af_alg_release_parent(sk);
330 static int skcipher_accept_parent_nokey(void *private, struct sock *sk)
332 struct af_alg_ctx *ctx;
333 struct alg_sock *ask = alg_sk(sk);
334 struct crypto_skcipher *tfm = private;
335 unsigned int len = sizeof(*ctx);
337 ctx = sock_kmalloc(sk, len, GFP_KERNEL);
341 ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(tfm),
344 sock_kfree_s(sk, ctx, len);
348 memset(ctx->iv, 0, crypto_skcipher_ivsize(tfm));
350 INIT_LIST_HEAD(&ctx->tsgl_list);
353 atomic_set(&ctx->rcvused, 0);
357 crypto_init_wait(&ctx->wait);
361 sk->sk_destruct = skcipher_sock_destruct;
366 static int skcipher_accept_parent(void *private, struct sock *sk)
368 struct crypto_skcipher *tfm = private;
370 if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
373 return skcipher_accept_parent_nokey(private, sk);
376 static const struct af_alg_type algif_type_skcipher = {
377 .bind = skcipher_bind,
378 .release = skcipher_release,
379 .setkey = skcipher_setkey,
380 .accept = skcipher_accept_parent,
381 .accept_nokey = skcipher_accept_parent_nokey,
382 .ops = &algif_skcipher_ops,
383 .ops_nokey = &algif_skcipher_ops_nokey,
388 static int __init algif_skcipher_init(void)
390 return af_alg_register_type(&algif_type_skcipher);
393 static void __exit algif_skcipher_exit(void)
395 int err = af_alg_unregister_type(&algif_type_skcipher);
399 module_init(algif_skcipher_init);
400 module_exit(algif_skcipher_exit);
401 MODULE_LICENSE("GPL");