linux/crypto/crypto_user.c
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   1/*
   2 * Crypto user configuration API.
   3 *
   4 * Copyright (C) 2011 secunet Security Networks AG
   5 * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
   6 *
   7 * This program is free software; you can redistribute it and/or modify it
   8 * under the terms and conditions of the GNU General Public License,
   9 * version 2, as published by the Free Software Foundation.
  10 *
  11 * This program is distributed in the hope it will be useful, but WITHOUT
  12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14 * more details.
  15 *
  16 * You should have received a copy of the GNU General Public License along with
  17 * this program; if not, write to the Free Software Foundation, Inc.,
  18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21#include <linux/module.h>
  22#include <linux/crypto.h>
  23#include <linux/cryptouser.h>
  24#include <net/netlink.h>
  25#include <linux/security.h>
  26#include <net/net_namespace.h>
  27#include "internal.h"
  28
  29DEFINE_MUTEX(crypto_cfg_mutex);
  30
  31/* The crypto netlink socket */
  32static struct sock *crypto_nlsk;
  33
  34struct crypto_dump_info {
  35        struct sk_buff *in_skb;
  36        struct sk_buff *out_skb;
  37        u32 nlmsg_seq;
  38        u16 nlmsg_flags;
  39};
  40
  41static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  42{
  43        struct crypto_alg *q, *alg = NULL;
  44
  45        down_read(&crypto_alg_sem);
  46
  47        list_for_each_entry(q, &crypto_alg_list, cra_list) {
  48                int match = 0;
  49
  50                if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  51                        continue;
  52
  53                if (strlen(p->cru_driver_name))
  54                        match = !strcmp(q->cra_driver_name,
  55                                        p->cru_driver_name);
  56                else if (!exact)
  57                        match = !strcmp(q->cra_name, p->cru_name);
  58
  59                if (match) {
  60                        alg = q;
  61                        break;
  62                }
  63        }
  64
  65        up_read(&crypto_alg_sem);
  66
  67        return alg;
  68}
  69
  70static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  71{
  72        struct crypto_report_cipher rcipher;
  73
  74        snprintf(rcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "cipher");
  75
  76        rcipher.blocksize = alg->cra_blocksize;
  77        rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  78        rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  79
  80        NLA_PUT(skb, CRYPTOCFGA_REPORT_CIPHER,
  81                sizeof(struct crypto_report_cipher), &rcipher);
  82
  83        return 0;
  84
  85nla_put_failure:
  86        return -EMSGSIZE;
  87}
  88
  89static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
  90{
  91        struct crypto_report_comp rcomp;
  92
  93        snprintf(rcomp.type, CRYPTO_MAX_ALG_NAME, "%s", "compression");
  94
  95        NLA_PUT(skb, CRYPTOCFGA_REPORT_COMPRESS,
  96                sizeof(struct crypto_report_comp), &rcomp);
  97
  98        return 0;
  99
 100nla_put_failure:
 101        return -EMSGSIZE;
 102}
 103
 104static int crypto_report_one(struct crypto_alg *alg,
 105                             struct crypto_user_alg *ualg, struct sk_buff *skb)
 106{
 107        memcpy(&ualg->cru_name, &alg->cra_name, sizeof(ualg->cru_name));
 108        memcpy(&ualg->cru_driver_name, &alg->cra_driver_name,
 109               sizeof(ualg->cru_driver_name));
 110        memcpy(&ualg->cru_module_name, module_name(alg->cra_module),
 111               CRYPTO_MAX_ALG_NAME);
 112
 113        ualg->cru_flags = alg->cra_flags;
 114        ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
 115
 116        NLA_PUT_U32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority);
 117
 118        if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 119                struct crypto_report_larval rl;
 120
 121                snprintf(rl.type, CRYPTO_MAX_ALG_NAME, "%s", "larval");
 122
 123                NLA_PUT(skb, CRYPTOCFGA_REPORT_LARVAL,
 124                        sizeof(struct crypto_report_larval), &rl);
 125
 126                goto out;
 127        }
 128
 129        if (alg->cra_type && alg->cra_type->report) {
 130                if (alg->cra_type->report(skb, alg))
 131                        goto nla_put_failure;
 132
 133                goto out;
 134        }
 135
 136        switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 137        case CRYPTO_ALG_TYPE_CIPHER:
 138                if (crypto_report_cipher(skb, alg))
 139                        goto nla_put_failure;
 140
 141                break;
 142        case CRYPTO_ALG_TYPE_COMPRESS:
 143                if (crypto_report_comp(skb, alg))
 144                        goto nla_put_failure;
 145
 146                break;
 147        }
 148
 149out:
 150        return 0;
 151
 152nla_put_failure:
 153        return -EMSGSIZE;
 154}
 155
 156static int crypto_report_alg(struct crypto_alg *alg,
 157                             struct crypto_dump_info *info)
 158{
 159        struct sk_buff *in_skb = info->in_skb;
 160        struct sk_buff *skb = info->out_skb;
 161        struct nlmsghdr *nlh;
 162        struct crypto_user_alg *ualg;
 163        int err = 0;
 164
 165        nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, info->nlmsg_seq,
 166                        CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 167        if (!nlh) {
 168                err = -EMSGSIZE;
 169                goto out;
 170        }
 171
 172        ualg = nlmsg_data(nlh);
 173
 174        err = crypto_report_one(alg, ualg, skb);
 175        if (err) {
 176                nlmsg_cancel(skb, nlh);
 177                goto out;
 178        }
 179
 180        nlmsg_end(skb, nlh);
 181
 182out:
 183        return err;
 184}
 185
 186static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 187                         struct nlattr **attrs)
 188{
 189        struct crypto_user_alg *p = nlmsg_data(in_nlh);
 190        struct crypto_alg *alg;
 191        struct sk_buff *skb;
 192        struct crypto_dump_info info;
 193        int err;
 194
 195        if (!p->cru_driver_name)
 196                return -EINVAL;
 197
 198        alg = crypto_alg_match(p, 1);
 199        if (!alg)
 200                return -ENOENT;
 201
 202        skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 203        if (!skb)
 204                return -ENOMEM;
 205
 206        info.in_skb = in_skb;
 207        info.out_skb = skb;
 208        info.nlmsg_seq = in_nlh->nlmsg_seq;
 209        info.nlmsg_flags = 0;
 210
 211        err = crypto_report_alg(alg, &info);
 212        if (err)
 213                return err;
 214
 215        return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).pid);
 216}
 217
 218static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 219{
 220        struct crypto_alg *alg;
 221        struct crypto_dump_info info;
 222        int err;
 223
 224        if (cb->args[0])
 225                goto out;
 226
 227        cb->args[0] = 1;
 228
 229        info.in_skb = cb->skb;
 230        info.out_skb = skb;
 231        info.nlmsg_seq = cb->nlh->nlmsg_seq;
 232        info.nlmsg_flags = NLM_F_MULTI;
 233
 234        list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 235                err = crypto_report_alg(alg, &info);
 236                if (err)
 237                        goto out_err;
 238        }
 239
 240out:
 241        return skb->len;
 242out_err:
 243        return err;
 244}
 245
 246static int crypto_dump_report_done(struct netlink_callback *cb)
 247{
 248        return 0;
 249}
 250
 251static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 252                             struct nlattr **attrs)
 253{
 254        struct crypto_alg *alg;
 255        struct crypto_user_alg *p = nlmsg_data(nlh);
 256        struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 257        LIST_HEAD(list);
 258
 259        if (priority && !strlen(p->cru_driver_name))
 260                return -EINVAL;
 261
 262        alg = crypto_alg_match(p, 1);
 263        if (!alg)
 264                return -ENOENT;
 265
 266        down_write(&crypto_alg_sem);
 267
 268        crypto_remove_spawns(alg, &list, NULL);
 269
 270        if (priority)
 271                alg->cra_priority = nla_get_u32(priority);
 272
 273        up_write(&crypto_alg_sem);
 274
 275        crypto_remove_final(&list);
 276
 277        return 0;
 278}
 279
 280static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 281                          struct nlattr **attrs)
 282{
 283        struct crypto_alg *alg;
 284        struct crypto_user_alg *p = nlmsg_data(nlh);
 285
 286        alg = crypto_alg_match(p, 1);
 287        if (!alg)
 288                return -ENOENT;
 289
 290        /* We can not unregister core algorithms such as aes-generic.
 291         * We would loose the reference in the crypto_alg_list to this algorithm
 292         * if we try to unregister. Unregistering such an algorithm without
 293         * removing the module is not possible, so we restrict to crypto
 294         * instances that are build from templates. */
 295        if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 296                return -EINVAL;
 297
 298        if (atomic_read(&alg->cra_refcnt) != 1)
 299                return -EBUSY;
 300
 301        return crypto_unregister_instance(alg);
 302}
 303
 304static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 305                          struct nlattr **attrs)
 306{
 307        int exact;
 308        const char *name;
 309        struct crypto_alg *alg;
 310        struct crypto_user_alg *p = nlmsg_data(nlh);
 311        struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 312
 313        if (strlen(p->cru_driver_name))
 314                exact = 1;
 315
 316        if (priority && !exact)
 317                return -EINVAL;
 318
 319        alg = crypto_alg_match(p, exact);
 320        if (alg)
 321                return -EEXIST;
 322
 323        if (strlen(p->cru_driver_name))
 324                name = p->cru_driver_name;
 325        else
 326                name = p->cru_name;
 327
 328        alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 329        if (IS_ERR(alg))
 330                return PTR_ERR(alg);
 331
 332        down_write(&crypto_alg_sem);
 333
 334        if (priority)
 335                alg->cra_priority = nla_get_u32(priority);
 336
 337        up_write(&crypto_alg_sem);
 338
 339        crypto_mod_put(alg);
 340
 341        return 0;
 342}
 343
 344#define MSGSIZE(type) sizeof(struct type)
 345
 346static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 347        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 348        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 349        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 350        [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 351};
 352
 353static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 354        [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 355};
 356
 357#undef MSGSIZE
 358
 359static struct crypto_link {
 360        int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 361        int (*dump)(struct sk_buff *, struct netlink_callback *);
 362        int (*done)(struct netlink_callback *);
 363} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 364        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 365        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 366        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 367        [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 368                                                       .dump = crypto_dump_report,
 369                                                       .done = crypto_dump_report_done},
 370};
 371
 372static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 373{
 374        struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 375        struct crypto_link *link;
 376        int type, err;
 377
 378        type = nlh->nlmsg_type;
 379        if (type > CRYPTO_MSG_MAX)
 380                return -EINVAL;
 381
 382        type -= CRYPTO_MSG_BASE;
 383        link = &crypto_dispatch[type];
 384
 385        if (!capable(CAP_NET_ADMIN))
 386                return -EPERM;
 387
 388        if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 389            (nlh->nlmsg_flags & NLM_F_DUMP))) {
 390                if (link->dump == NULL)
 391                        return -EINVAL;
 392
 393                return netlink_dump_start(crypto_nlsk, skb, nlh,
 394                                          link->dump, link->done, 0);
 395        }
 396
 397        err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 398                          crypto_policy);
 399        if (err < 0)
 400                return err;
 401
 402        if (link->doit == NULL)
 403                return -EINVAL;
 404
 405        return link->doit(skb, nlh, attrs);
 406}
 407
 408static void crypto_netlink_rcv(struct sk_buff *skb)
 409{
 410        mutex_lock(&crypto_cfg_mutex);
 411        netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 412        mutex_unlock(&crypto_cfg_mutex);
 413}
 414
 415static int __init crypto_user_init(void)
 416{
 417        crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO,
 418                                            0, crypto_netlink_rcv,
 419                                            NULL, THIS_MODULE);
 420        if (!crypto_nlsk)
 421                return -ENOMEM;
 422
 423        return 0;
 424}
 425
 426static void __exit crypto_user_exit(void)
 427{
 428        netlink_kernel_release(crypto_nlsk);
 429}
 430
 431module_init(crypto_user_init);
 432module_exit(crypto_user_exit);
 433MODULE_LICENSE("GPL");
 434MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 435MODULE_DESCRIPTION("Crypto userspace configuration API");
 436