linux/crypto/crypto_user_base.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Crypto user configuration API.
   4 *
   5 * Copyright (C) 2011 secunet Security Networks AG
   6 * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/crypto.h>
  11#include <linux/cryptouser.h>
  12#include <linux/sched.h>
  13#include <linux/security.h>
  14#include <net/netlink.h>
  15#include <net/net_namespace.h>
  16#include <net/sock.h>
  17#include <crypto/internal/skcipher.h>
  18#include <crypto/internal/rng.h>
  19#include <crypto/akcipher.h>
  20#include <crypto/kpp.h>
  21#include <crypto/internal/cryptouser.h>
  22
  23#include "internal.h"
  24
  25#define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  26
  27static DEFINE_MUTEX(crypto_cfg_mutex);
  28
  29struct crypto_dump_info {
  30        struct sk_buff *in_skb;
  31        struct sk_buff *out_skb;
  32        u32 nlmsg_seq;
  33        u16 nlmsg_flags;
  34};
  35
  36struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  37{
  38        struct crypto_alg *q, *alg = NULL;
  39
  40        down_read(&crypto_alg_sem);
  41
  42        list_for_each_entry(q, &crypto_alg_list, cra_list) {
  43                int match = 0;
  44
  45                if (crypto_is_larval(q))
  46                        continue;
  47
  48                if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  49                        continue;
  50
  51                if (strlen(p->cru_driver_name))
  52                        match = !strcmp(q->cra_driver_name,
  53                                        p->cru_driver_name);
  54                else if (!exact)
  55                        match = !strcmp(q->cra_name, p->cru_name);
  56
  57                if (!match)
  58                        continue;
  59
  60                if (unlikely(!crypto_mod_get(q)))
  61                        continue;
  62
  63                alg = q;
  64                break;
  65        }
  66
  67        up_read(&crypto_alg_sem);
  68
  69        return alg;
  70}
  71
  72static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  73{
  74        struct crypto_report_cipher rcipher;
  75
  76        memset(&rcipher, 0, sizeof(rcipher));
  77
  78        strscpy(rcipher.type, "cipher", sizeof(rcipher.type));
  79
  80        rcipher.blocksize = alg->cra_blocksize;
  81        rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  82        rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  83
  84        return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  85                       sizeof(rcipher), &rcipher);
  86}
  87
  88static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
  89{
  90        struct crypto_report_comp rcomp;
  91
  92        memset(&rcomp, 0, sizeof(rcomp));
  93
  94        strscpy(rcomp.type, "compression", sizeof(rcomp.type));
  95
  96        return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
  97}
  98
  99static int crypto_report_one(struct crypto_alg *alg,
 100                             struct crypto_user_alg *ualg, struct sk_buff *skb)
 101{
 102        memset(ualg, 0, sizeof(*ualg));
 103
 104        strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 105        strscpy(ualg->cru_driver_name, alg->cra_driver_name,
 106                sizeof(ualg->cru_driver_name));
 107        strscpy(ualg->cru_module_name, module_name(alg->cra_module),
 108                sizeof(ualg->cru_module_name));
 109
 110        ualg->cru_type = 0;
 111        ualg->cru_mask = 0;
 112        ualg->cru_flags = alg->cra_flags;
 113        ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
 114
 115        if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 116                goto nla_put_failure;
 117        if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 118                struct crypto_report_larval rl;
 119
 120                memset(&rl, 0, sizeof(rl));
 121                strscpy(rl.type, "larval", sizeof(rl.type));
 122                if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
 123                        goto nla_put_failure;
 124                goto out;
 125        }
 126
 127        if (alg->cra_type && alg->cra_type->report) {
 128                if (alg->cra_type->report(skb, alg))
 129                        goto nla_put_failure;
 130
 131                goto out;
 132        }
 133
 134        switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 135        case CRYPTO_ALG_TYPE_CIPHER:
 136                if (crypto_report_cipher(skb, alg))
 137                        goto nla_put_failure;
 138
 139                break;
 140        case CRYPTO_ALG_TYPE_COMPRESS:
 141                if (crypto_report_comp(skb, alg))
 142                        goto nla_put_failure;
 143
 144                break;
 145        }
 146
 147out:
 148        return 0;
 149
 150nla_put_failure:
 151        return -EMSGSIZE;
 152}
 153
 154static int crypto_report_alg(struct crypto_alg *alg,
 155                             struct crypto_dump_info *info)
 156{
 157        struct sk_buff *in_skb = info->in_skb;
 158        struct sk_buff *skb = info->out_skb;
 159        struct nlmsghdr *nlh;
 160        struct crypto_user_alg *ualg;
 161        int err = 0;
 162
 163        nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 164                        CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 165        if (!nlh) {
 166                err = -EMSGSIZE;
 167                goto out;
 168        }
 169
 170        ualg = nlmsg_data(nlh);
 171
 172        err = crypto_report_one(alg, ualg, skb);
 173        if (err) {
 174                nlmsg_cancel(skb, nlh);
 175                goto out;
 176        }
 177
 178        nlmsg_end(skb, nlh);
 179
 180out:
 181        return err;
 182}
 183
 184static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 185                         struct nlattr **attrs)
 186{
 187        struct net *net = sock_net(in_skb->sk);
 188        struct crypto_user_alg *p = nlmsg_data(in_nlh);
 189        struct crypto_alg *alg;
 190        struct sk_buff *skb;
 191        struct crypto_dump_info info;
 192        int err;
 193
 194        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 195                return -EINVAL;
 196
 197        alg = crypto_alg_match(p, 0);
 198        if (!alg)
 199                return -ENOENT;
 200
 201        err = -ENOMEM;
 202        skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 203        if (!skb)
 204                goto drop_alg;
 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
 213drop_alg:
 214        crypto_mod_put(alg);
 215
 216        if (err) {
 217                kfree_skb(skb);
 218                return err;
 219        }
 220
 221        return nlmsg_unicast(net->crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 222}
 223
 224static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 225{
 226        const size_t start_pos = cb->args[0];
 227        size_t pos = 0;
 228        struct crypto_dump_info info;
 229        struct crypto_alg *alg;
 230        int res;
 231
 232        info.in_skb = cb->skb;
 233        info.out_skb = skb;
 234        info.nlmsg_seq = cb->nlh->nlmsg_seq;
 235        info.nlmsg_flags = NLM_F_MULTI;
 236
 237        down_read(&crypto_alg_sem);
 238        list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 239                if (pos >= start_pos) {
 240                        res = crypto_report_alg(alg, &info);
 241                        if (res == -EMSGSIZE)
 242                                break;
 243                        if (res)
 244                                goto out;
 245                }
 246                pos++;
 247        }
 248        cb->args[0] = pos;
 249        res = skb->len;
 250out:
 251        up_read(&crypto_alg_sem);
 252        return res;
 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 (!netlink_capable(skb, CAP_NET_ADMIN))
 269                return -EPERM;
 270
 271        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 272                return -EINVAL;
 273
 274        if (priority && !strlen(p->cru_driver_name))
 275                return -EINVAL;
 276
 277        alg = crypto_alg_match(p, 1);
 278        if (!alg)
 279                return -ENOENT;
 280
 281        down_write(&crypto_alg_sem);
 282
 283        crypto_remove_spawns(alg, &list, NULL);
 284
 285        if (priority)
 286                alg->cra_priority = nla_get_u32(priority);
 287
 288        up_write(&crypto_alg_sem);
 289
 290        crypto_mod_put(alg);
 291        crypto_remove_final(&list);
 292
 293        return 0;
 294}
 295
 296static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 297                          struct nlattr **attrs)
 298{
 299        struct crypto_alg *alg;
 300        struct crypto_user_alg *p = nlmsg_data(nlh);
 301        int err;
 302
 303        if (!netlink_capable(skb, CAP_NET_ADMIN))
 304                return -EPERM;
 305
 306        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 307                return -EINVAL;
 308
 309        alg = crypto_alg_match(p, 1);
 310        if (!alg)
 311                return -ENOENT;
 312
 313        /* We can not unregister core algorithms such as aes-generic.
 314         * We would loose the reference in the crypto_alg_list to this algorithm
 315         * if we try to unregister. Unregistering such an algorithm without
 316         * removing the module is not possible, so we restrict to crypto
 317         * instances that are build from templates. */
 318        err = -EINVAL;
 319        if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 320                goto drop_alg;
 321
 322        err = -EBUSY;
 323        if (refcount_read(&alg->cra_refcnt) > 2)
 324                goto drop_alg;
 325
 326        crypto_unregister_instance((struct crypto_instance *)alg);
 327        err = 0;
 328
 329drop_alg:
 330        crypto_mod_put(alg);
 331        return err;
 332}
 333
 334static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 335                          struct nlattr **attrs)
 336{
 337        int exact = 0;
 338        const char *name;
 339        struct crypto_alg *alg;
 340        struct crypto_user_alg *p = nlmsg_data(nlh);
 341        struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 342
 343        if (!netlink_capable(skb, CAP_NET_ADMIN))
 344                return -EPERM;
 345
 346        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 347                return -EINVAL;
 348
 349        if (strlen(p->cru_driver_name))
 350                exact = 1;
 351
 352        if (priority && !exact)
 353                return -EINVAL;
 354
 355        alg = crypto_alg_match(p, exact);
 356        if (alg) {
 357                crypto_mod_put(alg);
 358                return -EEXIST;
 359        }
 360
 361        if (strlen(p->cru_driver_name))
 362                name = p->cru_driver_name;
 363        else
 364                name = p->cru_name;
 365
 366        alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 367        if (IS_ERR(alg))
 368                return PTR_ERR(alg);
 369
 370        down_write(&crypto_alg_sem);
 371
 372        if (priority)
 373                alg->cra_priority = nla_get_u32(priority);
 374
 375        up_write(&crypto_alg_sem);
 376
 377        crypto_mod_put(alg);
 378
 379        return 0;
 380}
 381
 382static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 383                          struct nlattr **attrs)
 384{
 385        if (!netlink_capable(skb, CAP_NET_ADMIN))
 386                return -EPERM;
 387        return crypto_del_default_rng();
 388}
 389
 390#define MSGSIZE(type) sizeof(struct type)
 391
 392static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 393        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 394        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 395        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 396        [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 397        [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 398        [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 399};
 400
 401static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 402        [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 403};
 404
 405#undef MSGSIZE
 406
 407static const struct crypto_link {
 408        int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 409        int (*dump)(struct sk_buff *, struct netlink_callback *);
 410        int (*done)(struct netlink_callback *);
 411} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 412        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 413        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 414        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 415        [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 416                                                       .dump = crypto_dump_report,
 417                                                       .done = crypto_dump_report_done},
 418        [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 419        [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
 420};
 421
 422static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 423                               struct netlink_ext_ack *extack)
 424{
 425        struct net *net = sock_net(skb->sk);
 426        struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 427        const struct crypto_link *link;
 428        int type, err;
 429
 430        type = nlh->nlmsg_type;
 431        if (type > CRYPTO_MSG_MAX)
 432                return -EINVAL;
 433
 434        type -= CRYPTO_MSG_BASE;
 435        link = &crypto_dispatch[type];
 436
 437        if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 438            (nlh->nlmsg_flags & NLM_F_DUMP))) {
 439                struct crypto_alg *alg;
 440                unsigned long dump_alloc = 0;
 441
 442                if (link->dump == NULL)
 443                        return -EINVAL;
 444
 445                down_read(&crypto_alg_sem);
 446                list_for_each_entry(alg, &crypto_alg_list, cra_list)
 447                        dump_alloc += CRYPTO_REPORT_MAXSIZE;
 448                up_read(&crypto_alg_sem);
 449
 450                {
 451                        struct netlink_dump_control c = {
 452                                .dump = link->dump,
 453                                .done = link->done,
 454                                .min_dump_alloc = min(dump_alloc, 65535UL),
 455                        };
 456                        err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
 457                }
 458
 459                return err;
 460        }
 461
 462        err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
 463                                     CRYPTOCFGA_MAX, crypto_policy, extack);
 464        if (err < 0)
 465                return err;
 466
 467        if (link->doit == NULL)
 468                return -EINVAL;
 469
 470        return link->doit(skb, nlh, attrs);
 471}
 472
 473static void crypto_netlink_rcv(struct sk_buff *skb)
 474{
 475        mutex_lock(&crypto_cfg_mutex);
 476        netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 477        mutex_unlock(&crypto_cfg_mutex);
 478}
 479
 480static int __net_init crypto_netlink_init(struct net *net)
 481{
 482        struct netlink_kernel_cfg cfg = {
 483                .input  = crypto_netlink_rcv,
 484        };
 485
 486        net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
 487        return net->crypto_nlsk == NULL ? -ENOMEM : 0;
 488}
 489
 490static void __net_exit crypto_netlink_exit(struct net *net)
 491{
 492        netlink_kernel_release(net->crypto_nlsk);
 493        net->crypto_nlsk = NULL;
 494}
 495
 496static struct pernet_operations crypto_netlink_net_ops = {
 497        .init = crypto_netlink_init,
 498        .exit = crypto_netlink_exit,
 499};
 500
 501static int __init crypto_user_init(void)
 502{
 503        return register_pernet_subsys(&crypto_netlink_net_ops);
 504}
 505
 506static void __exit crypto_user_exit(void)
 507{
 508        unregister_pernet_subsys(&crypto_netlink_net_ops);
 509}
 510
 511module_init(crypto_user_init);
 512module_exit(crypto_user_exit);
 513MODULE_LICENSE("GPL");
 514MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 515MODULE_DESCRIPTION("Crypto userspace configuration API");
 516MODULE_ALIAS("net-pf-16-proto-21");
 517
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