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
 24struct 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
 37static int hash_sendmsg(struct kiocb *unused, struct socket *sock,
 38			struct msghdr *msg, size_t ignored)
 39{
 40	int limit = ALG_MAX_PAGES * PAGE_SIZE;
 41	struct sock *sk = sock->sk;
 42	struct alg_sock *ask = alg_sk(sk);
 43	struct hash_ctx *ctx = ask->private;
 44	unsigned long iovlen;
 45	struct iovec *iov;
 46	long copied = 0;
 47	int err;
 48
 49	if (limit > sk->sk_sndbuf)
 50		limit = sk->sk_sndbuf;
 51
 52	lock_sock(sk);
 53	if (!ctx->more) {
 54		err = crypto_ahash_init(&ctx->req);
 55		if (err)
 56			goto unlock;
 57	}
 58
 59	ctx->more = 0;
 60
 61	for (iov = msg->msg_iov, iovlen = msg->msg_iovlen; iovlen > 0;
 62	     iovlen--, iov++) {
 63		unsigned long seglen = iov->iov_len;
 64		char __user *from = iov->iov_base;
 65
 66		while (seglen) {
 67			int len = min_t(unsigned long, seglen, limit);
 68			int newlen;
 69
 70			newlen = af_alg_make_sg(&ctx->sgl, from, len, 0);
 71			if (newlen < 0) {
 72				err = copied ? 0 : newlen;
 73				goto unlock;
 74			}
 75
 76			ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL,
 77						newlen);
 78
 79			err = af_alg_wait_for_completion(
 80				crypto_ahash_update(&ctx->req),
 81				&ctx->completion);
 82
 83			af_alg_free_sg(&ctx->sgl);
 84
 85			if (err)
 86				goto unlock;
 87
 88			seglen -= newlen;
 89			from += newlen;
 90			copied += newlen;
 91		}
 92	}
 93
 94	err = 0;
 95
 96	ctx->more = msg->msg_flags & MSG_MORE;
 97	if (!ctx->more) {
 98		ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
 99		err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
100						 &ctx->completion);
101	}
102
103unlock:
104	release_sock(sk);
105
106	return err ?: copied;
107}
108
109static ssize_t hash_sendpage(struct socket *sock, struct page *page,
110			     int offset, size_t size, int flags)
111{
112	struct sock *sk = sock->sk;
113	struct alg_sock *ask = alg_sk(sk);
114	struct hash_ctx *ctx = ask->private;
115	int err;
116
117	lock_sock(sk);
118	sg_init_table(ctx->sgl.sg, 1);
119	sg_set_page(ctx->sgl.sg, page, size, offset);
120
121	ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);
122
123	if (!(flags & MSG_MORE)) {
124		if (ctx->more)
125			err = crypto_ahash_finup(&ctx->req);
126		else
127			err = crypto_ahash_digest(&ctx->req);
128	} else {
129		if (!ctx->more) {
130			err = crypto_ahash_init(&ctx->req);
131			if (err)
132				goto unlock;
133		}
134
135		err = crypto_ahash_update(&ctx->req);
136	}
137
138	err = af_alg_wait_for_completion(err, &ctx->completion);
139	if (err)
140		goto unlock;
141
142	ctx->more = flags & MSG_MORE;
143
144unlock:
145	release_sock(sk);
146
147	return err ?: size;
148}
149
150static int hash_recvmsg(struct kiocb *unused, struct socket *sock,
151			struct msghdr *msg, size_t len, int flags)
152{
153	struct sock *sk = sock->sk;
154	struct alg_sock *ask = alg_sk(sk);
155	struct hash_ctx *ctx = ask->private;
156	unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
157	int err;
158
159	if (len > ds)
160		len = ds;
161	else if (len < ds)
162		msg->msg_flags |= MSG_TRUNC;
163
164	lock_sock(sk);
165	if (ctx->more) {
166		ctx->more = 0;
167		ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
168		err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
169						 &ctx->completion);
170		if (err)
171			goto unlock;
172	}
173
174	err = memcpy_toiovec(msg->msg_iov, ctx->result, len);
175
176unlock:
177	release_sock(sk);
178
179	return err ?: len;
180}
181
182static int hash_accept(struct socket *sock, struct socket *newsock, int flags)
183{
184	struct sock *sk = sock->sk;
185	struct alg_sock *ask = alg_sk(sk);
186	struct hash_ctx *ctx = ask->private;
187	struct ahash_request *req = &ctx->req;
188	char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req))];
189	struct sock *sk2;
190	struct alg_sock *ask2;
191	struct hash_ctx *ctx2;
192	int err;
193
194	err = crypto_ahash_export(req, state);
195	if (err)
196		return err;
197
198	err = af_alg_accept(ask->parent, newsock);
199	if (err)
200		return err;
201
202	sk2 = newsock->sk;
203	ask2 = alg_sk(sk2);
204	ctx2 = ask2->private;
205	ctx2->more = 1;
206
207	err = crypto_ahash_import(&ctx2->req, state);
208	if (err) {
209		sock_orphan(sk2);
210		sock_put(sk2);
211	}
212
213	return err;
214}
215
216static struct proto_ops algif_hash_ops = {
217	.family		=	PF_ALG,
218
219	.connect	=	sock_no_connect,
220	.socketpair	=	sock_no_socketpair,
221	.getname	=	sock_no_getname,
222	.ioctl		=	sock_no_ioctl,
223	.listen		=	sock_no_listen,
224	.shutdown	=	sock_no_shutdown,
225	.getsockopt	=	sock_no_getsockopt,
226	.mmap		=	sock_no_mmap,
227	.bind		=	sock_no_bind,
228	.setsockopt	=	sock_no_setsockopt,
229	.poll		=	sock_no_poll,
230
231	.release	=	af_alg_release,
232	.sendmsg	=	hash_sendmsg,
233	.sendpage	=	hash_sendpage,
234	.recvmsg	=	hash_recvmsg,
235	.accept		=	hash_accept,
236};
237
238static void *hash_bind(const char *name, u32 type, u32 mask)
239{
240	return crypto_alloc_ahash(name, type, mask);
241}
242
243static void hash_release(void *private)
244{
245	crypto_free_ahash(private);
246}
247
248static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
249{
250	return crypto_ahash_setkey(private, key, keylen);
251}
252
253static void hash_sock_destruct(struct sock *sk)
254{
255	struct alg_sock *ask = alg_sk(sk);
256	struct hash_ctx *ctx = ask->private;
257
258	sock_kfree_s(sk, ctx->result,
259		     crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)));
260	sock_kfree_s(sk, ctx, ctx->len);
261	af_alg_release_parent(sk);
262}
263
264static int hash_accept_parent(void *private, struct sock *sk)
265{
266	struct hash_ctx *ctx;
267	struct alg_sock *ask = alg_sk(sk);
268	unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(private);
269	unsigned ds = crypto_ahash_digestsize(private);
270
271	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
272	if (!ctx)
273		return -ENOMEM;
274
275	ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
276	if (!ctx->result) {
277		sock_kfree_s(sk, ctx, len);
278		return -ENOMEM;
279	}
280
281	memset(ctx->result, 0, ds);
282
283	ctx->len = len;
284	ctx->more = 0;
285	af_alg_init_completion(&ctx->completion);
286
287	ask->private = ctx;
288
289	ahash_request_set_tfm(&ctx->req, private);
290	ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
291				   af_alg_complete, &ctx->completion);
292
293	sk->sk_destruct = hash_sock_destruct;
294
295	return 0;
296}
297
298static const struct af_alg_type algif_type_hash = {
299	.bind		=	hash_bind,
300	.release	=	hash_release,
301	.setkey		=	hash_setkey,
302	.accept		=	hash_accept_parent,
303	.ops		=	&algif_hash_ops,
304	.name		=	"hash",
305	.owner		=	THIS_MODULE
306};
307
308static int __init algif_hash_init(void)
309{
310	return af_alg_register_type(&algif_type_hash);
311}
312
313static void __exit algif_hash_exit(void)
314{
315	int err = af_alg_unregister_type(&algif_type_hash);
316	BUG_ON(err);
317}
318
319module_init(algif_hash_init);
320module_exit(algif_hash_exit);
321MODULE_LICENSE("GPL");