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