linux/crypto/algif_hash.c
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   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 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
  92unlock:
  93        release_sock(sk);
  94
  95        return err ?: copied;
  96}
  97
  98static 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
 136unlock:
 137        release_sock(sk);
 138
 139        return err ?: size;
 140}
 141
 142static 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
 168unlock:
 169        release_sock(sk);
 170
 171        return err ?: len;
 172}
 173
 174static 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
 208static 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
 230static void *hash_bind(const char *name, u32 type, u32 mask)
 231{
 232        return crypto_alloc_ahash(name, type, mask);
 233}
 234
 235static void hash_release(void *private)
 236{
 237        crypto_free_ahash(private);
 238}
 239
 240static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
 241{
 242        return crypto_ahash_setkey(private, key, keylen);
 243}
 244
 245static 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
 256static 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
 290static 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
 300static int __init algif_hash_init(void)
 301{
 302        return af_alg_register_type(&algif_type_hash);
 303}
 304
 305static void __exit algif_hash_exit(void)
 306{
 307        int err = af_alg_unregister_type(&algif_type_hash);
 308        BUG_ON(err);
 309}
 310
 311module_init(algif_hash_init);
 312module_exit(algif_hash_exit);
 313MODULE_LICENSE("GPL");
 314