Root/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
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    if (flags & MSG_SENDPAGE_NOTLAST)
118        flags |= MSG_MORE;
119
120    lock_sock(sk);
121    sg_init_table(ctx->sgl.sg, 1);
122    sg_set_page(ctx->sgl.sg, page, size, offset);
123
124    ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);
125
126    if (!(flags & MSG_MORE)) {
127        if (ctx->more)
128            err = crypto_ahash_finup(&ctx->req);
129        else
130            err = crypto_ahash_digest(&ctx->req);
131    } else {
132        if (!ctx->more) {
133            err = crypto_ahash_init(&ctx->req);
134            if (err)
135                goto unlock;
136        }
137
138        err = crypto_ahash_update(&ctx->req);
139    }
140
141    err = af_alg_wait_for_completion(err, &ctx->completion);
142    if (err)
143        goto unlock;
144
145    ctx->more = flags & MSG_MORE;
146
147unlock:
148    release_sock(sk);
149
150    return err ?: size;
151}
152
153static int hash_recvmsg(struct kiocb *unused, struct socket *sock,
154            struct msghdr *msg, size_t len, int flags)
155{
156    struct sock *sk = sock->sk;
157    struct alg_sock *ask = alg_sk(sk);
158    struct hash_ctx *ctx = ask->private;
159    unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
160    int err;
161
162    if (len > ds)
163        len = ds;
164    else if (len < ds)
165        msg->msg_flags |= MSG_TRUNC;
166
167    lock_sock(sk);
168    if (ctx->more) {
169        ctx->more = 0;
170        ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
171        err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
172                         &ctx->completion);
173        if (err)
174            goto unlock;
175    }
176
177    err = memcpy_toiovec(msg->msg_iov, ctx->result, len);
178
179unlock:
180    release_sock(sk);
181
182    return err ?: len;
183}
184
185static int hash_accept(struct socket *sock, struct socket *newsock, int flags)
186{
187    struct sock *sk = sock->sk;
188    struct alg_sock *ask = alg_sk(sk);
189    struct hash_ctx *ctx = ask->private;
190    struct ahash_request *req = &ctx->req;
191    char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req))];
192    struct sock *sk2;
193    struct alg_sock *ask2;
194    struct hash_ctx *ctx2;
195    int err;
196
197    err = crypto_ahash_export(req, state);
198    if (err)
199        return err;
200
201    err = af_alg_accept(ask->parent, newsock);
202    if (err)
203        return err;
204
205    sk2 = newsock->sk;
206    ask2 = alg_sk(sk2);
207    ctx2 = ask2->private;
208    ctx2->more = 1;
209
210    err = crypto_ahash_import(&ctx2->req, state);
211    if (err) {
212        sock_orphan(sk2);
213        sock_put(sk2);
214    }
215
216    return err;
217}
218
219static struct proto_ops algif_hash_ops = {
220    .family = PF_ALG,
221
222    .connect = sock_no_connect,
223    .socketpair = sock_no_socketpair,
224    .getname = sock_no_getname,
225    .ioctl = sock_no_ioctl,
226    .listen = sock_no_listen,
227    .shutdown = sock_no_shutdown,
228    .getsockopt = sock_no_getsockopt,
229    .mmap = sock_no_mmap,
230    .bind = sock_no_bind,
231    .setsockopt = sock_no_setsockopt,
232    .poll = sock_no_poll,
233
234    .release = af_alg_release,
235    .sendmsg = hash_sendmsg,
236    .sendpage = hash_sendpage,
237    .recvmsg = hash_recvmsg,
238    .accept = hash_accept,
239};
240
241static void *hash_bind(const char *name, u32 type, u32 mask)
242{
243    return crypto_alloc_ahash(name, type, mask);
244}
245
246static void hash_release(void *private)
247{
248    crypto_free_ahash(private);
249}
250
251static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
252{
253    return crypto_ahash_setkey(private, key, keylen);
254}
255
256static void hash_sock_destruct(struct sock *sk)
257{
258    struct alg_sock *ask = alg_sk(sk);
259    struct hash_ctx *ctx = ask->private;
260
261    sock_kfree_s(sk, ctx->result,
262             crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)));
263    sock_kfree_s(sk, ctx, ctx->len);
264    af_alg_release_parent(sk);
265}
266
267static int hash_accept_parent(void *private, struct sock *sk)
268{
269    struct hash_ctx *ctx;
270    struct alg_sock *ask = alg_sk(sk);
271    unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(private);
272    unsigned ds = crypto_ahash_digestsize(private);
273
274    ctx = sock_kmalloc(sk, len, GFP_KERNEL);
275    if (!ctx)
276        return -ENOMEM;
277
278    ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
279    if (!ctx->result) {
280        sock_kfree_s(sk, ctx, len);
281        return -ENOMEM;
282    }
283
284    memset(ctx->result, 0, ds);
285
286    ctx->len = len;
287    ctx->more = 0;
288    af_alg_init_completion(&ctx->completion);
289
290    ask->private = ctx;
291
292    ahash_request_set_tfm(&ctx->req, private);
293    ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
294                   af_alg_complete, &ctx->completion);
295
296    sk->sk_destruct = hash_sock_destruct;
297
298    return 0;
299}
300
301static const struct af_alg_type algif_type_hash = {
302    .bind = hash_bind,
303    .release = hash_release,
304    .setkey = hash_setkey,
305    .accept = hash_accept_parent,
306    .ops = &algif_hash_ops,
307    .name = "hash",
308    .owner = THIS_MODULE
309};
310
311static int __init algif_hash_init(void)
312{
313    return af_alg_register_type(&algif_type_hash);
314}
315
316static void __exit algif_hash_exit(void)
317{
318    int err = af_alg_unregister_type(&algif_type_hash);
319    BUG_ON(err);
320}
321
322module_init(algif_hash_init);
323module_exit(algif_hash_exit);
324MODULE_LICENSE("GPL");
325

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