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