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

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