net/sched/act_pedit.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/act_pedit.c        Generic packet editor
   4  *
   5  * Authors:     Jamal Hadi Salim (2002-4)
   6  */
   7
   8 #include <linux/types.h>
   9 #include <linux/kernel.h>
  10 #include <linux/string.h>
  11 #include <linux/errno.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/rtnetlink.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <net/netlink.h>
  18 #include <net/pkt_sched.h>
  19 #include <linux/tc_act/tc_pedit.h>
  20 #include <net/tc_act/tc_pedit.h>
  21 #include <uapi/linux/tc_act/tc_pedit.h>
  22 #include <net/pkt_cls.h>
  23
  24 static unsigned int pedit_net_id;
  25 static struct tc_action_ops act_pedit_ops;
  26
  27 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  28         [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tc_pedit) },
  29         [TCA_PEDIT_PARMS_EX]    = { .len = sizeof(struct tc_pedit) },
  30         [TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
  31 };
  32
  33 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
  34         [TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
  35         [TCA_PEDIT_KEY_EX_CMD]    = { .type = NLA_U16 },
  36 };
  37
  38 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
  39                                                         u8 n)
  40 {
  41         struct tcf_pedit_key_ex *keys_ex;
  42         struct tcf_pedit_key_ex *k;
  43         const struct nlattr *ka;
  44         int err = -EINVAL;
  45         int rem;
  46
  47         if (!nla)
  48                 return NULL;
  49
  50         keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
  51         if (!keys_ex)
  52                 return ERR_PTR(-ENOMEM);
  53
  54         k = keys_ex;
  55
  56         nla_for_each_nested(ka, nla, rem) {
  57                 struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
  58
  59                 if (!n) {
  60                         err = -EINVAL;
  61                         goto err_out;
  62                 }
  63                 n--;
  64
  65                 if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
  66                         err = -EINVAL;
  67                         goto err_out;
  68                 }
  69
  70                 err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
  71                                                   ka, pedit_key_ex_policy,
  72                                                   NULL);
  73                 if (err)
  74                         goto err_out;
  75
  76                 if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
  77                     !tb[TCA_PEDIT_KEY_EX_CMD]) {
  78                         err = -EINVAL;
  79                         goto err_out;
  80                 }
  81
  82                 k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
  83                 k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
  84
  85                 if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
  86                     k->cmd > TCA_PEDIT_CMD_MAX) {
  87                         err = -EINVAL;
  88                         goto err_out;
  89                 }
  90
  91                 k++;
  92         }
  93
  94         if (n) {
  95                 err = -EINVAL;
  96                 goto err_out;
  97         }
  98
  99         return keys_ex;
 100
 101 err_out:
 102         kfree(keys_ex);
 103         return ERR_PTR(err);
 104 }
 105
 106 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
 107                                  struct tcf_pedit_key_ex *keys_ex, int n)
 108 {
 109         struct nlattr *keys_start = nla_nest_start_noflag(skb,
 110                                                           TCA_PEDIT_KEYS_EX);
 111
 112         if (!keys_start)
 113                 goto nla_failure;
 114         for (; n > 0; n--) {
 115                 struct nlattr *key_start;
 116
 117                 key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
 118                 if (!key_start)
 119                         goto nla_failure;
 120
 121                 if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
 122                     nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
 123                         goto nla_failure;
 124
 125                 nla_nest_end(skb, key_start);
 126
 127                 keys_ex++;
 128         }
 129
 130         nla_nest_end(skb, keys_start);
 131
 132         return 0;
 133 nla_failure:
 134         nla_nest_cancel(skb, keys_start);
 135         return -EINVAL;
 136 }
 137
 138 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 139                           struct nlattr *est, struct tc_action **a,
 140                           int ovr, int bind, bool rtnl_held,
 141                           struct tcf_proto *tp, struct netlink_ext_ack *extack)
 142 {
 143         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 144         struct nlattr *tb[TCA_PEDIT_MAX + 1];
 145         struct tcf_chain *goto_ch = NULL;
 146         struct tc_pedit_key *keys = NULL;
 147         struct tcf_pedit_key_ex *keys_ex;
 148         struct tc_pedit *parm;
 149         struct nlattr *pattr;
 150         struct tcf_pedit *p;
 151         int ret = 0, err;
 152         int i, ksize;
 153         u32 index;
 154
 155         if (!nla) {
 156                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
 157                 return -EINVAL;
 158         }
 159
 160         err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
 161                                           pedit_policy, NULL);
 162         if (err < 0)
 163                 return err;
 164
 165         pattr = tb[TCA_PEDIT_PARMS];
 166         if (!pattr)
 167                 pattr = tb[TCA_PEDIT_PARMS_EX];
 168         if (!pattr) {
 169                 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
 170                 return -EINVAL;
 171         }
 172
 173         parm = nla_data(pattr);
 174         if (!parm->nkeys) {
 175                 NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 176                 return -EINVAL;
 177         }
 178         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 179         if (nla_len(pattr) < sizeof(*parm) + ksize) {
 180                 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
 181                 return -EINVAL;
 182         }
 183
 184         keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 185         if (IS_ERR(keys_ex))
 186                 return PTR_ERR(keys_ex);
 187
 188         index = parm->index;
 189         err = tcf_idr_check_alloc(tn, &index, a, bind);
 190         if (!err) {
 191                 ret = tcf_idr_create(tn, index, est, a,
 192                                      &act_pedit_ops, bind, false);
 193                 if (ret) {
 194                         tcf_idr_cleanup(tn, index);
 195                         goto out_free;
 196                 }
 197                 ret = ACT_P_CREATED;
 198         } else if (err > 0) {
 199                 if (bind)
 200                         goto out_free;
 201                 if (!ovr) {
 202                         ret = -EEXIST;
 203                         goto out_release;
 204                 }
 205         } else {
 206                 ret = err;
 207                 goto out_free;
 208         }
 209
 210         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 211         if (err < 0) {
 212                 ret = err;
 213                 goto out_release;
 214         }
 215         p = to_pedit(*a);
 216         spin_lock_bh(&p->tcf_lock);
 217
 218         if (ret == ACT_P_CREATED ||
 219             (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
 220                 keys = kmalloc(ksize, GFP_ATOMIC);
 221                 if (!keys) {
 222                         spin_unlock_bh(&p->tcf_lock);
 223                         ret = -ENOMEM;
 224                         goto put_chain;
 225                 }
 226                 kfree(p->tcfp_keys);
 227                 p->tcfp_keys = keys;
 228                 p->tcfp_nkeys = parm->nkeys;
 229         }
 230         memcpy(p->tcfp_keys, parm->keys, ksize);
 231         p->tcfp_off_max_hint = 0;
 232         for (i = 0; i < p->tcfp_nkeys; ++i) {
 233                 u32 cur = p->tcfp_keys[i].off;
 234
 235                 /* sanitize the shift value for any later use */
 236                 p->tcfp_keys[i].shift = min_t(size_t, BITS_PER_TYPE(int) - 1,
 237                                               p->tcfp_keys[i].shift);
 238
 239                 /* The AT option can read a single byte, we can bound the actual
 240                  * value with uchar max.
 241                  */
 242                 cur += (0xff & p->tcfp_keys[i].offmask) >> p->tcfp_keys[i].shift;
 243
 244                 /* Each key touches 4 bytes starting from the computed offset */
 245                 p->tcfp_off_max_hint = max(p->tcfp_off_max_hint, cur + 4);
 246         }
 247
 248         p->tcfp_flags = parm->flags;
 249         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 250
 251         kfree(p->tcfp_keys_ex);
 252         p->tcfp_keys_ex = keys_ex;
 253
 254         spin_unlock_bh(&p->tcf_lock);
 255         if (goto_ch)
 256                 tcf_chain_put_by_act(goto_ch);
 257         return ret;
 258
 259 put_chain:
 260         if (goto_ch)
 261                 tcf_chain_put_by_act(goto_ch);
 262 out_release:
 263         tcf_idr_release(*a, bind);
 264 out_free:
 265         kfree(keys_ex);
 266         return ret;
 267
 268 }
 269
 270 static void tcf_pedit_cleanup(struct tc_action *a)
 271 {
 272         struct tcf_pedit *p = to_pedit(a);
 273         struct tc_pedit_key *keys = p->tcfp_keys;
 274
 275         kfree(keys);
 276         kfree(p->tcfp_keys_ex);
 277 }
 278
 279 static bool offset_valid(struct sk_buff *skb, int offset)
 280 {
 281         if (offset > 0 && offset > skb->len)
 282                 return false;
 283
 284         if  (offset < 0 && -offset > skb_headroom(skb))
 285                 return false;
 286
 287         return true;
 288 }
 289
 290 static int pedit_skb_hdr_offset(struct sk_buff *skb,
 291                                 enum pedit_header_type htype, int *hoffset)
 292 {
 293         int ret = -EINVAL;
 294
 295         switch (htype) {
 296         case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 297                 if (skb_mac_header_was_set(skb)) {
 298                         *hoffset = skb_mac_offset(skb);
 299                         ret = 0;
 300                 }
 301                 break;
 302         case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 303         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 304         case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 305                 *hoffset = skb_network_offset(skb);
 306                 ret = 0;
 307                 break;
 308         case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 309         case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 310                 if (skb_transport_header_was_set(skb)) {
 311                         *hoffset = skb_transport_offset(skb);
 312                         ret = 0;
 313                 }
 314                 break;
 315         default:
 316                 ret = -EINVAL;
 317                 break;
 318         }
 319
 320         return ret;
 321 }
 322
 323 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
 324                          struct tcf_result *res)
 325 {
 326         struct tcf_pedit *p = to_pedit(a);
 327         u32 max_offset;
 328         int i;
 329
 330         spin_lock(&p->tcf_lock);
 331
 332         max_offset = (skb_transport_header_was_set(skb) ?
 333                       skb_transport_offset(skb) :
 334                       skb_network_offset(skb)) +
 335                      p->tcfp_off_max_hint;
 336         if (skb_ensure_writable(skb, min(skb->len, max_offset)))
 337                 goto unlock;
 338
 339         tcf_lastuse_update(&p->tcf_tm);
 340
 341         if (p->tcfp_nkeys > 0) {
 342                 struct tc_pedit_key *tkey = p->tcfp_keys;
 343                 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
 344                 enum pedit_header_type htype =
 345                         TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 346                 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 347
 348                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 349                         u32 *ptr, hdata;
 350                         int offset = tkey->off;
 351                         int hoffset;
 352                         u32 val;
 353                         int rc;
 354
 355                         if (tkey_ex) {
 356                                 htype = tkey_ex->htype;
 357                                 cmd = tkey_ex->cmd;
 358
 359                                 tkey_ex++;
 360                         }
 361
 362                         rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 363                         if (rc) {
 364                                 pr_info("tc action pedit bad header type specified (0x%x)\n",
 365                                         htype);
 366                                 goto bad;
 367                         }
 368
 369                         if (tkey->offmask) {
 370                                 u8 *d, _d;
 371
 372                                 if (!offset_valid(skb, hoffset + tkey->at)) {
 373                                         pr_info("tc action pedit 'at' offset %d out of bounds\n",
 374                                                 hoffset + tkey->at);
 375                                         goto bad;
 376                                 }
 377                                 d = skb_header_pointer(skb, hoffset + tkey->at,
 378                                                        sizeof(_d), &_d);
 379                                 if (!d)
 380                                         goto bad;
 381                                 offset += (*d & tkey->offmask) >> tkey->shift;
 382                         }
 383
 384                         if (offset % 4) {
 385                                 pr_info("tc action pedit offset must be on 32 bit boundaries\n");
 386                                 goto bad;
 387                         }
 388
 389                         if (!offset_valid(skb, hoffset + offset)) {
 390                                 pr_info("tc action pedit offset %d out of bounds\n",
 391                                         hoffset + offset);
 392                                 goto bad;
 393                         }
 394
 395                         ptr = skb_header_pointer(skb, hoffset + offset,
 396                                                  sizeof(hdata), &hdata);
 397                         if (!ptr)
 398                                 goto bad;
 399                         /* just do it, baby */
 400                         switch (cmd) {
 401                         case TCA_PEDIT_KEY_EX_CMD_SET:
 402                                 val = tkey->val;
 403                                 break;
 404                         case TCA_PEDIT_KEY_EX_CMD_ADD:
 405                                 val = (*ptr + tkey->val) & ~tkey->mask;
 406                                 break;
 407                         default:
 408                                 pr_info("tc action pedit bad command (%d)\n",
 409                                         cmd);
 410                                 goto bad;
 411                         }
 412
 413                         *ptr = ((*ptr & tkey->mask) ^ val);
 414                         if (ptr == &hdata)
 415                                 skb_store_bits(skb, hoffset + offset, ptr, 4);
 416                 }
 417
 418                 goto done;
 419         } else {
 420                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 421         }
 422
 423 bad:
 424         p->tcf_qstats.overlimits++;
 425 done:
 426         bstats_update(&p->tcf_bstats, skb);
 427 unlock:
 428         spin_unlock(&p->tcf_lock);
 429         return p->tcf_action;
 430 }
 431
 432 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 433                           int bind, int ref)
 434 {
 435         unsigned char *b = skb_tail_pointer(skb);
 436         struct tcf_pedit *p = to_pedit(a);
 437         struct tc_pedit *opt;
 438         struct tcf_t t;
 439         int s;
 440
 441         s = struct_size(opt, keys, p->tcfp_nkeys);
 442
 443         /* netlink spinlocks held above us - must use ATOMIC */
 444         opt = kzalloc(s, GFP_ATOMIC);
 445         if (unlikely(!opt))
 446                 return -ENOBUFS;
 447
 448         spin_lock_bh(&p->tcf_lock);
 449         memcpy(opt->keys, p->tcfp_keys,
 450                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 451         opt->index = p->tcf_index;
 452         opt->nkeys = p->tcfp_nkeys;
 453         opt->flags = p->tcfp_flags;
 454         opt->action = p->tcf_action;
 455         opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 456         opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 457
 458         if (p->tcfp_keys_ex) {
 459                 if (tcf_pedit_key_ex_dump(skb,
 460                                           p->tcfp_keys_ex,
 461                                           p->tcfp_nkeys))
 462                         goto nla_put_failure;
 463
 464                 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 465                         goto nla_put_failure;
 466         } else {
 467                 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 468                         goto nla_put_failure;
 469         }
 470
 471         tcf_tm_dump(&t, &p->tcf_tm);
 472         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 473                 goto nla_put_failure;
 474         spin_unlock_bh(&p->tcf_lock);
 475
 476         kfree(opt);
 477         return skb->len;
 478
 479 nla_put_failure:
 480         spin_unlock_bh(&p->tcf_lock);
 481         nlmsg_trim(skb, b);
 482         kfree(opt);
 483         return -1;
 484 }
 485
 486 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 487                             struct netlink_callback *cb, int type,
 488                             const struct tc_action_ops *ops,
 489                             struct netlink_ext_ack *extack)
 490 {
 491         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 492
 493         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 494 }
 495
 496 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 497 {
 498         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 499
 500         return tcf_idr_search(tn, a, index);
 501 }
 502
 503 static struct tc_action_ops act_pedit_ops = {
 504         .kind           =       "pedit",
 505         .id             =       TCA_ID_PEDIT,
 506         .owner          =       THIS_MODULE,
 507         .act            =       tcf_pedit_act,
 508         .dump           =       tcf_pedit_dump,
 509         .cleanup        =       tcf_pedit_cleanup,
 510         .init           =       tcf_pedit_init,
 511         .walk           =       tcf_pedit_walker,
 512         .lookup         =       tcf_pedit_search,
 513         .size           =       sizeof(struct tcf_pedit),
 514 };
 515
 516 static __net_init int pedit_init_net(struct net *net)
 517 {
 518         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 519
 520         return tc_action_net_init(net, tn, &act_pedit_ops);
 521 }
 522
 523 static void __net_exit pedit_exit_net(struct list_head *net_list)
 524 {
 525         tc_action_net_exit(net_list, pedit_net_id);
 526 }
 527
 528 static struct pernet_operations pedit_net_ops = {
 529         .init = pedit_init_net,
 530         .exit_batch = pedit_exit_net,
 531         .id   = &pedit_net_id,
 532         .size = sizeof(struct tc_action_net),
 533 };
 534
 535 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 536 MODULE_DESCRIPTION("Generic Packet Editor actions");
 537 MODULE_LICENSE("GPL");
 538
 539 static int __init pedit_init_module(void)
 540 {
 541         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 542 }
 543
 544 static void __exit pedit_cleanup_module(void)
 545 {
 546         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 547 }
 548
 549 module_init(pedit_init_module);
 550 module_exit(pedit_cleanup_module);