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 <linux/sched.h>
  25#include <net/netlink.h>
  26#include <linux/security.h>
  27#include <net/net_namespace.h>
  28#include <crypto/internal/aead.h>
  29#include <crypto/internal/skcipher.h>
  30
  31#include "internal.h"
  32
  33#define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  34
  35static DEFINE_MUTEX(crypto_cfg_mutex);
  36
  37/* The crypto netlink socket */
  38static struct sock *crypto_nlsk;
  39
  40struct crypto_dump_info {
  41        struct sk_buff *in_skb;
  42        struct sk_buff *out_skb;
  43        u32 nlmsg_seq;
  44        u16 nlmsg_flags;
  45};
  46
  47static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  48{
  49        struct crypto_alg *q, *alg = NULL;
  50
  51        down_read(&crypto_alg_sem);
  52
  53        list_for_each_entry(q, &crypto_alg_list, cra_list) {
  54                int match = 0;
  55
  56                if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  57                        continue;
  58
  59                if (strlen(p->cru_driver_name))
  60                        match = !strcmp(q->cra_driver_name,
  61                                        p->cru_driver_name);
  62                else if (!exact)
  63                        match = !strcmp(q->cra_name, p->cru_name);
  64
  65                if (match) {
  66                        alg = q;
  67                        break;
  68                }
  69        }
  70
  71        up_read(&crypto_alg_sem);
  72
  73        return alg;
  74}
  75
  76static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  77{
  78        struct crypto_report_cipher rcipher;
  79
  80        strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
  81
  82        rcipher.blocksize = alg->cra_blocksize;
  83        rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  84        rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  85
  86        if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  87                    sizeof(struct crypto_report_cipher), &rcipher))
  88                goto nla_put_failure;
  89        return 0;
  90
  91nla_put_failure:
  92        return -EMSGSIZE;
  93}
  94
  95static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
  96{
  97        struct crypto_report_comp rcomp;
  98
  99        strncpy(rcomp.type, "compression", sizeof(rcomp.type));
 100        if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
 101                    sizeof(struct crypto_report_comp), &rcomp))
 102                goto nla_put_failure;
 103        return 0;
 104
 105nla_put_failure:
 106        return -EMSGSIZE;
 107}
 108
 109static int crypto_report_one(struct crypto_alg *alg,
 110                             struct crypto_user_alg *ualg, struct sk_buff *skb)
 111{
 112        strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 113        strncpy(ualg->cru_driver_name, alg->cra_driver_name,
 114                sizeof(ualg->cru_driver_name));
 115        strncpy(ualg->cru_module_name, module_name(alg->cra_module),
 116                sizeof(ualg->cru_module_name));
 117
 118        ualg->cru_type = 0;
 119        ualg->cru_mask = 0;
 120        ualg->cru_flags = alg->cra_flags;
 121        ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
 122
 123        if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 124                goto nla_put_failure;
 125        if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 126                struct crypto_report_larval rl;
 127
 128                strncpy(rl.type, "larval", sizeof(rl.type));
 129                if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
 130                            sizeof(struct crypto_report_larval), &rl))
 131                        goto nla_put_failure;
 132                goto out;
 133        }
 134
 135        if (alg->cra_type && alg->cra_type->report) {
 136                if (alg->cra_type->report(skb, alg))
 137                        goto nla_put_failure;
 138
 139                goto out;
 140        }
 141
 142        switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 143        case CRYPTO_ALG_TYPE_CIPHER:
 144                if (crypto_report_cipher(skb, alg))
 145                        goto nla_put_failure;
 146
 147                break;
 148        case CRYPTO_ALG_TYPE_COMPRESS:
 149                if (crypto_report_comp(skb, alg))
 150                        goto nla_put_failure;
 151
 152                break;
 153        }
 154
 155out:
 156        return 0;
 157
 158nla_put_failure:
 159        return -EMSGSIZE;
 160}
 161
 162static int crypto_report_alg(struct crypto_alg *alg,
 163                             struct crypto_dump_info *info)
 164{
 165        struct sk_buff *in_skb = info->in_skb;
 166        struct sk_buff *skb = info->out_skb;
 167        struct nlmsghdr *nlh;
 168        struct crypto_user_alg *ualg;
 169        int err = 0;
 170
 171        nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 172                        CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 173        if (!nlh) {
 174                err = -EMSGSIZE;
 175                goto out;
 176        }
 177
 178        ualg = nlmsg_data(nlh);
 179
 180        err = crypto_report_one(alg, ualg, skb);
 181        if (err) {
 182                nlmsg_cancel(skb, nlh);
 183                goto out;
 184        }
 185
 186        nlmsg_end(skb, nlh);
 187
 188out:
 189        return err;
 190}
 191
 192static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 193                         struct nlattr **attrs)
 194{
 195        struct crypto_user_alg *p = nlmsg_data(in_nlh);
 196        struct crypto_alg *alg;
 197        struct sk_buff *skb;
 198        struct crypto_dump_info info;
 199        int err;
 200
 201        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 202                return -EINVAL;
 203
 204        if (!p->cru_driver_name[0])
 205                return -EINVAL;
 206
 207        alg = crypto_alg_match(p, 1);
 208        if (!alg)
 209                return -ENOENT;
 210
 211        skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 212        if (!skb)
 213                return -ENOMEM;
 214
 215        info.in_skb = in_skb;
 216        info.out_skb = skb;
 217        info.nlmsg_seq = in_nlh->nlmsg_seq;
 218        info.nlmsg_flags = 0;
 219
 220        err = crypto_report_alg(alg, &info);
 221        if (err)
 222                return err;
 223
 224        return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 225}
 226
 227static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 228{
 229        struct crypto_alg *alg;
 230        struct crypto_dump_info info;
 231        int err;
 232
 233        if (cb->args[0])
 234                goto out;
 235
 236        cb->args[0] = 1;
 237
 238        info.in_skb = cb->skb;
 239        info.out_skb = skb;
 240        info.nlmsg_seq = cb->nlh->nlmsg_seq;
 241        info.nlmsg_flags = NLM_F_MULTI;
 242
 243        list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 244                err = crypto_report_alg(alg, &info);
 245                if (err)
 246                        goto out_err;
 247        }
 248
 249out:
 250        return skb->len;
 251out_err:
 252        return err;
 253}
 254
 255static int crypto_dump_report_done(struct netlink_callback *cb)
 256{
 257        return 0;
 258}
 259
 260static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 261                             struct nlattr **attrs)
 262{
 263        struct crypto_alg *alg;
 264        struct crypto_user_alg *p = nlmsg_data(nlh);
 265        struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 266        LIST_HEAD(list);
 267
 268        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 269                return -EINVAL;
 270
 271        if (priority && !strlen(p->cru_driver_name))
 272                return -EINVAL;
 273
 274        alg = crypto_alg_match(p, 1);
 275        if (!alg)
 276                return -ENOENT;
 277
 278        down_write(&crypto_alg_sem);
 279
 280        crypto_remove_spawns(alg, &list, NULL);
 281
 282        if (priority)
 283                alg->cra_priority = nla_get_u32(priority);
 284
 285        up_write(&crypto_alg_sem);
 286
 287        crypto_remove_final(&list);
 288
 289        return 0;
 290}
 291
 292static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 293                          struct nlattr **attrs)
 294{
 295        struct crypto_alg *alg;
 296        struct crypto_user_alg *p = nlmsg_data(nlh);
 297
 298        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 299                return -EINVAL;
 300
 301        alg = crypto_alg_match(p, 1);
 302        if (!alg)
 303                return -ENOENT;
 304
 305        /* We can not unregister core algorithms such as aes-generic.
 306         * We would loose the reference in the crypto_alg_list to this algorithm
 307         * if we try to unregister. Unregistering such an algorithm without
 308         * removing the module is not possible, so we restrict to crypto
 309         * instances that are build from templates. */
 310        if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 311                return -EINVAL;
 312
 313        if (atomic_read(&alg->cra_refcnt) != 1)
 314                return -EBUSY;
 315
 316        return crypto_unregister_instance(alg);
 317}
 318
 319static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
 320                                                   u32 mask)
 321{
 322        int err;
 323        struct crypto_alg *alg;
 324
 325        type = crypto_skcipher_type(type);
 326        mask = crypto_skcipher_mask(mask);
 327
 328        for (;;) {
 329                alg = crypto_lookup_skcipher(name,  type, mask);
 330                if (!IS_ERR(alg))
 331                        return alg;
 332
 333                err = PTR_ERR(alg);
 334                if (err != -EAGAIN)
 335                        break;
 336                if (signal_pending(current)) {
 337                        err = -EINTR;
 338                        break;
 339                }
 340        }
 341
 342        return ERR_PTR(err);
 343}
 344
 345static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
 346                                               u32 mask)
 347{
 348        int err;
 349        struct crypto_alg *alg;
 350
 351        type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 352        type |= CRYPTO_ALG_TYPE_AEAD;
 353        mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 354        mask |= CRYPTO_ALG_TYPE_MASK;
 355
 356        for (;;) {
 357                alg = crypto_lookup_aead(name,  type, mask);
 358                if (!IS_ERR(alg))
 359                        return alg;
 360
 361                err = PTR_ERR(alg);
 362                if (err != -EAGAIN)
 363                        break;
 364                if (signal_pending(current)) {
 365                        err = -EINTR;
 366                        break;
 367                }
 368        }
 369
 370        return ERR_PTR(err);
 371}
 372
 373static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 374                          struct nlattr **attrs)
 375{
 376        int exact = 0;
 377        const char *name;
 378        struct crypto_alg *alg;
 379        struct crypto_user_alg *p = nlmsg_data(nlh);
 380        struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 381
 382        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 383                return -EINVAL;
 384
 385        if (strlen(p->cru_driver_name))
 386                exact = 1;
 387
 388        if (priority && !exact)
 389                return -EINVAL;
 390
 391        alg = crypto_alg_match(p, exact);
 392        if (alg)
 393                return -EEXIST;
 394
 395        if (strlen(p->cru_driver_name))
 396                name = p->cru_driver_name;
 397        else
 398                name = p->cru_name;
 399
 400        switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
 401        case CRYPTO_ALG_TYPE_AEAD:
 402                alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
 403                break;
 404        case CRYPTO_ALG_TYPE_GIVCIPHER:
 405        case CRYPTO_ALG_TYPE_BLKCIPHER:
 406        case CRYPTO_ALG_TYPE_ABLKCIPHER:
 407                alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
 408                break;
 409        default:
 410                alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 411        }
 412
 413        if (IS_ERR(alg))
 414                return PTR_ERR(alg);
 415
 416        down_write(&crypto_alg_sem);
 417
 418        if (priority)
 419                alg->cra_priority = nla_get_u32(priority);
 420
 421        up_write(&crypto_alg_sem);
 422
 423        crypto_mod_put(alg);
 424
 425        return 0;
 426}
 427
 428#define MSGSIZE(type) sizeof(struct type)
 429
 430static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 431        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 432        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 433        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 434        [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 435};
 436
 437static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 438        [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 439};
 440
 441#undef MSGSIZE
 442
 443static const struct crypto_link {
 444        int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 445        int (*dump)(struct sk_buff *, struct netlink_callback *);
 446        int (*done)(struct netlink_callback *);
 447} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 448        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 449        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 450        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 451        [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 452                                                       .dump = crypto_dump_report,
 453                                                       .done = crypto_dump_report_done},
 454};
 455
 456static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 457{
 458        struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 459        const struct crypto_link *link;
 460        int type, err;
 461
 462        type = nlh->nlmsg_type;
 463        if (type > CRYPTO_MSG_MAX)
 464                return -EINVAL;
 465
 466        type -= CRYPTO_MSG_BASE;
 467        link = &crypto_dispatch[type];
 468
 469        if (!capable(CAP_NET_ADMIN))
 470                return -EPERM;
 471
 472        if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 473            (nlh->nlmsg_flags & NLM_F_DUMP))) {
 474                struct crypto_alg *alg;
 475                u16 dump_alloc = 0;
 476
 477                if (link->dump == NULL)
 478                        return -EINVAL;
 479
 480                list_for_each_entry(alg, &crypto_alg_list, cra_list)
 481                        dump_alloc += CRYPTO_REPORT_MAXSIZE;
 482
 483                {
 484                        struct netlink_dump_control c = {
 485                                .dump = link->dump,
 486                                .done = link->done,
 487                                .min_dump_alloc = dump_alloc,
 488                        };
 489                        return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 490                }
 491        }
 492
 493        err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 494                          crypto_policy);
 495        if (err < 0)
 496                return err;
 497
 498        if (link->doit == NULL)
 499                return -EINVAL;
 500
 501        return link->doit(skb, nlh, attrs);
 502}
 503
 504static void crypto_netlink_rcv(struct sk_buff *skb)
 505{
 506        mutex_lock(&crypto_cfg_mutex);
 507        netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 508        mutex_unlock(&crypto_cfg_mutex);
 509}
 510
 511static int __init crypto_user_init(void)
 512{
 513        struct netlink_kernel_cfg cfg = {
 514                .input  = crypto_netlink_rcv,
 515        };
 516
 517        crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 518        if (!crypto_nlsk)
 519                return -ENOMEM;
 520
 521        return 0;
 522}
 523
 524static void __exit crypto_user_exit(void)
 525{
 526        netlink_kernel_release(crypto_nlsk);
 527}
 528
 529module_init(crypto_user_init);
 530module_exit(crypto_user_exit);
 531MODULE_LICENSE("GPL");
 532MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 533MODULE_DESCRIPTION("Crypto userspace configuration API");
 534
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