~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/netfilter/nfnetlink_cthelper.c

Version: ~ [ linux-5.8 ] ~ [ linux-5.7.14 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.57 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.138 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.193 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.232 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.232 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  * (C) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
  4  *
  5  * This software has been sponsored by Vyatta Inc. <http://www.vyatta.com>
  6  */
  7 #include <linux/init.h>
  8 #include <linux/module.h>
  9 #include <linux/kernel.h>
 10 #include <linux/skbuff.h>
 11 #include <linux/netlink.h>
 12 #include <linux/rculist.h>
 13 #include <linux/slab.h>
 14 #include <linux/types.h>
 15 #include <linux/list.h>
 16 #include <linux/errno.h>
 17 #include <linux/capability.h>
 18 #include <net/netlink.h>
 19 #include <net/sock.h>
 20 
 21 #include <net/netfilter/nf_conntrack_helper.h>
 22 #include <net/netfilter/nf_conntrack_expect.h>
 23 #include <net/netfilter/nf_conntrack_ecache.h>
 24 
 25 #include <linux/netfilter/nfnetlink.h>
 26 #include <linux/netfilter/nfnetlink_conntrack.h>
 27 #include <linux/netfilter/nfnetlink_cthelper.h>
 28 
 29 MODULE_LICENSE("GPL");
 30 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 31 MODULE_DESCRIPTION("nfnl_cthelper: User-space connection tracking helpers");
 32 
 33 struct nfnl_cthelper {
 34         struct list_head                list;
 35         struct nf_conntrack_helper      helper;
 36 };
 37 
 38 static LIST_HEAD(nfnl_cthelper_list);
 39 
 40 static int
 41 nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
 42                         struct nf_conn *ct, enum ip_conntrack_info ctinfo)
 43 {
 44         const struct nf_conn_help *help;
 45         struct nf_conntrack_helper *helper;
 46 
 47         help = nfct_help(ct);
 48         if (help == NULL)
 49                 return NF_DROP;
 50 
 51         /* rcu_read_lock()ed by nf_hook_thresh */
 52         helper = rcu_dereference(help->helper);
 53         if (helper == NULL)
 54                 return NF_DROP;
 55 
 56         /* This is a user-space helper not yet configured, skip. */
 57         if ((helper->flags &
 58             (NF_CT_HELPER_F_USERSPACE | NF_CT_HELPER_F_CONFIGURED)) ==
 59              NF_CT_HELPER_F_USERSPACE)
 60                 return NF_ACCEPT;
 61 
 62         /* If the user-space helper is not available, don't block traffic. */
 63         return NF_QUEUE_NR(helper->queue_num) | NF_VERDICT_FLAG_QUEUE_BYPASS;
 64 }
 65 
 66 static const struct nla_policy nfnl_cthelper_tuple_pol[NFCTH_TUPLE_MAX+1] = {
 67         [NFCTH_TUPLE_L3PROTONUM] = { .type = NLA_U16, },
 68         [NFCTH_TUPLE_L4PROTONUM] = { .type = NLA_U8, },
 69 };
 70 
 71 static int
 72 nfnl_cthelper_parse_tuple(struct nf_conntrack_tuple *tuple,
 73                           const struct nlattr *attr)
 74 {
 75         int err;
 76         struct nlattr *tb[NFCTH_TUPLE_MAX+1];
 77 
 78         err = nla_parse_nested_deprecated(tb, NFCTH_TUPLE_MAX, attr,
 79                                           nfnl_cthelper_tuple_pol, NULL);
 80         if (err < 0)
 81                 return err;
 82 
 83         if (!tb[NFCTH_TUPLE_L3PROTONUM] || !tb[NFCTH_TUPLE_L4PROTONUM])
 84                 return -EINVAL;
 85 
 86         /* Not all fields are initialized so first zero the tuple */
 87         memset(tuple, 0, sizeof(struct nf_conntrack_tuple));
 88 
 89         tuple->src.l3num = ntohs(nla_get_be16(tb[NFCTH_TUPLE_L3PROTONUM]));
 90         tuple->dst.protonum = nla_get_u8(tb[NFCTH_TUPLE_L4PROTONUM]);
 91 
 92         return 0;
 93 }
 94 
 95 static int
 96 nfnl_cthelper_from_nlattr(struct nlattr *attr, struct nf_conn *ct)
 97 {
 98         struct nf_conn_help *help = nfct_help(ct);
 99 
100         if (attr == NULL)
101                 return -EINVAL;
102 
103         if (help->helper->data_len == 0)
104                 return -EINVAL;
105 
106         nla_memcpy(help->data, nla_data(attr), sizeof(help->data));
107         return 0;
108 }
109 
110 static int
111 nfnl_cthelper_to_nlattr(struct sk_buff *skb, const struct nf_conn *ct)
112 {
113         const struct nf_conn_help *help = nfct_help(ct);
114 
115         if (help->helper->data_len &&
116             nla_put(skb, CTA_HELP_INFO, help->helper->data_len, &help->data))
117                 goto nla_put_failure;
118 
119         return 0;
120 
121 nla_put_failure:
122         return -ENOSPC;
123 }
124 
125 static const struct nla_policy nfnl_cthelper_expect_pol[NFCTH_POLICY_MAX+1] = {
126         [NFCTH_POLICY_NAME] = { .type = NLA_NUL_STRING,
127                                 .len = NF_CT_HELPER_NAME_LEN-1 },
128         [NFCTH_POLICY_EXPECT_MAX] = { .type = NLA_U32, },
129         [NFCTH_POLICY_EXPECT_TIMEOUT] = { .type = NLA_U32, },
130 };
131 
132 static int
133 nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
134                             const struct nlattr *attr)
135 {
136         int err;
137         struct nlattr *tb[NFCTH_POLICY_MAX+1];
138 
139         err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_MAX, attr,
140                                           nfnl_cthelper_expect_pol, NULL);
141         if (err < 0)
142                 return err;
143 
144         if (!tb[NFCTH_POLICY_NAME] ||
145             !tb[NFCTH_POLICY_EXPECT_MAX] ||
146             !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
147                 return -EINVAL;
148 
149         nla_strlcpy(expect_policy->name,
150                     tb[NFCTH_POLICY_NAME], NF_CT_HELPER_NAME_LEN);
151         expect_policy->max_expected =
152                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
153         if (expect_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
154                 return -EINVAL;
155 
156         expect_policy->timeout =
157                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
158 
159         return 0;
160 }
161 
162 static const struct nla_policy
163 nfnl_cthelper_expect_policy_set[NFCTH_POLICY_SET_MAX+1] = {
164         [NFCTH_POLICY_SET_NUM] = { .type = NLA_U32, },
165 };
166 
167 static int
168 nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
169                                   const struct nlattr *attr)
170 {
171         int i, ret;
172         struct nf_conntrack_expect_policy *expect_policy;
173         struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
174         unsigned int class_max;
175 
176         ret = nla_parse_nested_deprecated(tb, NFCTH_POLICY_SET_MAX, attr,
177                                           nfnl_cthelper_expect_policy_set,
178                                           NULL);
179         if (ret < 0)
180                 return ret;
181 
182         if (!tb[NFCTH_POLICY_SET_NUM])
183                 return -EINVAL;
184 
185         class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
186         if (class_max == 0)
187                 return -EINVAL;
188         if (class_max > NF_CT_MAX_EXPECT_CLASSES)
189                 return -EOVERFLOW;
190 
191         expect_policy = kcalloc(class_max,
192                                 sizeof(struct nf_conntrack_expect_policy),
193                                 GFP_KERNEL);
194         if (expect_policy == NULL)
195                 return -ENOMEM;
196 
197         for (i = 0; i < class_max; i++) {
198                 if (!tb[NFCTH_POLICY_SET+i])
199                         goto err;
200 
201                 ret = nfnl_cthelper_expect_policy(&expect_policy[i],
202                                                   tb[NFCTH_POLICY_SET+i]);
203                 if (ret < 0)
204                         goto err;
205         }
206 
207         helper->expect_class_max = class_max - 1;
208         helper->expect_policy = expect_policy;
209         return 0;
210 err:
211         kfree(expect_policy);
212         return -EINVAL;
213 }
214 
215 static int
216 nfnl_cthelper_create(const struct nlattr * const tb[],
217                      struct nf_conntrack_tuple *tuple)
218 {
219         struct nf_conntrack_helper *helper;
220         struct nfnl_cthelper *nfcth;
221         unsigned int size;
222         int ret;
223 
224         if (!tb[NFCTH_TUPLE] || !tb[NFCTH_POLICY] || !tb[NFCTH_PRIV_DATA_LEN])
225                 return -EINVAL;
226 
227         nfcth = kzalloc(sizeof(*nfcth), GFP_KERNEL);
228         if (nfcth == NULL)
229                 return -ENOMEM;
230         helper = &nfcth->helper;
231 
232         ret = nfnl_cthelper_parse_expect_policy(helper, tb[NFCTH_POLICY]);
233         if (ret < 0)
234                 goto err1;
235 
236         nla_strlcpy(helper->name,
237                     tb[NFCTH_NAME], NF_CT_HELPER_NAME_LEN);
238         size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
239         if (size > FIELD_SIZEOF(struct nf_conn_help, data)) {
240                 ret = -ENOMEM;
241                 goto err2;
242         }
243 
244         helper->flags |= NF_CT_HELPER_F_USERSPACE;
245         memcpy(&helper->tuple, tuple, sizeof(struct nf_conntrack_tuple));
246 
247         helper->me = THIS_MODULE;
248         helper->help = nfnl_userspace_cthelper;
249         helper->from_nlattr = nfnl_cthelper_from_nlattr;
250         helper->to_nlattr = nfnl_cthelper_to_nlattr;
251 
252         /* Default to queue number zero, this can be updated at any time. */
253         if (tb[NFCTH_QUEUE_NUM])
254                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
255 
256         if (tb[NFCTH_STATUS]) {
257                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
258 
259                 switch(status) {
260                 case NFCT_HELPER_STATUS_ENABLED:
261                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
262                         break;
263                 case NFCT_HELPER_STATUS_DISABLED:
264                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
265                         break;
266                 }
267         }
268 
269         ret = nf_conntrack_helper_register(helper);
270         if (ret < 0)
271                 goto err2;
272 
273         list_add_tail(&nfcth->list, &nfnl_cthelper_list);
274         return 0;
275 err2:
276         kfree(helper->expect_policy);
277 err1:
278         kfree(nfcth);
279         return ret;
280 }
281 
282 static int
283 nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy,
284                                 struct nf_conntrack_expect_policy *new_policy,
285                                 const struct nlattr *attr)
286 {
287         struct nlattr *tb[NFCTH_POLICY_MAX + 1];
288         int err;
289 
290         err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_MAX, attr,
291                                           nfnl_cthelper_expect_pol, NULL);
292         if (err < 0)
293                 return err;
294 
295         if (!tb[NFCTH_POLICY_NAME] ||
296             !tb[NFCTH_POLICY_EXPECT_MAX] ||
297             !tb[NFCTH_POLICY_EXPECT_TIMEOUT])
298                 return -EINVAL;
299 
300         if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name))
301                 return -EBUSY;
302 
303         new_policy->max_expected =
304                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
305         if (new_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
306                 return -EINVAL;
307 
308         new_policy->timeout =
309                 ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT]));
310 
311         return 0;
312 }
313 
314 static int nfnl_cthelper_update_policy_all(struct nlattr *tb[],
315                                            struct nf_conntrack_helper *helper)
316 {
317         struct nf_conntrack_expect_policy *new_policy;
318         struct nf_conntrack_expect_policy *policy;
319         int i, ret = 0;
320 
321         new_policy = kmalloc_array(helper->expect_class_max + 1,
322                                    sizeof(*new_policy), GFP_KERNEL);
323         if (!new_policy)
324                 return -ENOMEM;
325 
326         /* Check first that all policy attributes are well-formed, so we don't
327          * leave things in inconsistent state on errors.
328          */
329         for (i = 0; i < helper->expect_class_max + 1; i++) {
330 
331                 if (!tb[NFCTH_POLICY_SET + i]) {
332                         ret = -EINVAL;
333                         goto err;
334                 }
335 
336                 ret = nfnl_cthelper_update_policy_one(&helper->expect_policy[i],
337                                                       &new_policy[i],
338                                                       tb[NFCTH_POLICY_SET + i]);
339                 if (ret < 0)
340                         goto err;
341         }
342         /* Now we can safely update them. */
343         for (i = 0; i < helper->expect_class_max + 1; i++) {
344                 policy = (struct nf_conntrack_expect_policy *)
345                                 &helper->expect_policy[i];
346                 policy->max_expected = new_policy->max_expected;
347                 policy->timeout = new_policy->timeout;
348         }
349 
350 err:
351         kfree(new_policy);
352         return ret;
353 }
354 
355 static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper,
356                                        const struct nlattr *attr)
357 {
358         struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1];
359         unsigned int class_max;
360         int err;
361 
362         err = nla_parse_nested_deprecated(tb, NFCTH_POLICY_SET_MAX, attr,
363                                           nfnl_cthelper_expect_policy_set,
364                                           NULL);
365         if (err < 0)
366                 return err;
367 
368         if (!tb[NFCTH_POLICY_SET_NUM])
369                 return -EINVAL;
370 
371         class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
372         if (helper->expect_class_max + 1 != class_max)
373                 return -EBUSY;
374 
375         return nfnl_cthelper_update_policy_all(tb, helper);
376 }
377 
378 static int
379 nfnl_cthelper_update(const struct nlattr * const tb[],
380                      struct nf_conntrack_helper *helper)
381 {
382         int ret;
383 
384         if (tb[NFCTH_PRIV_DATA_LEN])
385                 return -EBUSY;
386 
387         if (tb[NFCTH_POLICY]) {
388                 ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]);
389                 if (ret < 0)
390                         return ret;
391         }
392         if (tb[NFCTH_QUEUE_NUM])
393                 helper->queue_num = ntohl(nla_get_be32(tb[NFCTH_QUEUE_NUM]));
394 
395         if (tb[NFCTH_STATUS]) {
396                 int status = ntohl(nla_get_be32(tb[NFCTH_STATUS]));
397 
398                 switch(status) {
399                 case NFCT_HELPER_STATUS_ENABLED:
400                         helper->flags |= NF_CT_HELPER_F_CONFIGURED;
401                         break;
402                 case NFCT_HELPER_STATUS_DISABLED:
403                         helper->flags &= ~NF_CT_HELPER_F_CONFIGURED;
404                         break;
405                 }
406         }
407         return 0;
408 }
409 
410 static int nfnl_cthelper_new(struct net *net, struct sock *nfnl,
411                              struct sk_buff *skb, const struct nlmsghdr *nlh,
412                              const struct nlattr * const tb[],
413                              struct netlink_ext_ack *extack)
414 {
415         const char *helper_name;
416         struct nf_conntrack_helper *cur, *helper = NULL;
417         struct nf_conntrack_tuple tuple;
418         struct nfnl_cthelper *nlcth;
419         int ret = 0;
420 
421         if (!capable(CAP_NET_ADMIN))
422                 return -EPERM;
423 
424         if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE])
425                 return -EINVAL;
426 
427         helper_name = nla_data(tb[NFCTH_NAME]);
428 
429         ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
430         if (ret < 0)
431                 return ret;
432 
433         list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
434                 cur = &nlcth->helper;
435 
436                 if (strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
437                         continue;
438 
439                 if ((tuple.src.l3num != cur->tuple.src.l3num ||
440                      tuple.dst.protonum != cur->tuple.dst.protonum))
441                         continue;
442 
443                 if (nlh->nlmsg_flags & NLM_F_EXCL)
444                         return -EEXIST;
445 
446                 helper = cur;
447                 break;
448         }
449 
450         if (helper == NULL)
451                 ret = nfnl_cthelper_create(tb, &tuple);
452         else
453                 ret = nfnl_cthelper_update(tb, helper);
454 
455         return ret;
456 }
457 
458 static int
459 nfnl_cthelper_dump_tuple(struct sk_buff *skb,
460                          struct nf_conntrack_helper *helper)
461 {
462         struct nlattr *nest_parms;
463 
464         nest_parms = nla_nest_start(skb, NFCTH_TUPLE);
465         if (nest_parms == NULL)
466                 goto nla_put_failure;
467 
468         if (nla_put_be16(skb, NFCTH_TUPLE_L3PROTONUM,
469                          htons(helper->tuple.src.l3num)))
470                 goto nla_put_failure;
471 
472         if (nla_put_u8(skb, NFCTH_TUPLE_L4PROTONUM, helper->tuple.dst.protonum))
473                 goto nla_put_failure;
474 
475         nla_nest_end(skb, nest_parms);
476         return 0;
477 
478 nla_put_failure:
479         return -1;
480 }
481 
482 static int
483 nfnl_cthelper_dump_policy(struct sk_buff *skb,
484                         struct nf_conntrack_helper *helper)
485 {
486         int i;
487         struct nlattr *nest_parms1, *nest_parms2;
488 
489         nest_parms1 = nla_nest_start(skb, NFCTH_POLICY);
490         if (nest_parms1 == NULL)
491                 goto nla_put_failure;
492 
493         if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
494                          htonl(helper->expect_class_max + 1)))
495                 goto nla_put_failure;
496 
497         for (i = 0; i < helper->expect_class_max + 1; i++) {
498                 nest_parms2 = nla_nest_start(skb, (NFCTH_POLICY_SET + i));
499                 if (nest_parms2 == NULL)
500                         goto nla_put_failure;
501 
502                 if (nla_put_string(skb, NFCTH_POLICY_NAME,
503                                    helper->expect_policy[i].name))
504                         goto nla_put_failure;
505 
506                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_MAX,
507                                  htonl(helper->expect_policy[i].max_expected)))
508                         goto nla_put_failure;
509 
510                 if (nla_put_be32(skb, NFCTH_POLICY_EXPECT_TIMEOUT,
511                                  htonl(helper->expect_policy[i].timeout)))
512                         goto nla_put_failure;
513 
514                 nla_nest_end(skb, nest_parms2);
515         }
516         nla_nest_end(skb, nest_parms1);
517         return 0;
518 
519 nla_put_failure:
520         return -1;
521 }
522 
523 static int
524 nfnl_cthelper_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
525                         int event, struct nf_conntrack_helper *helper)
526 {
527         struct nlmsghdr *nlh;
528         struct nfgenmsg *nfmsg;
529         unsigned int flags = portid ? NLM_F_MULTI : 0;
530         int status;
531 
532         event = nfnl_msg_type(NFNL_SUBSYS_CTHELPER, event);
533         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
534         if (nlh == NULL)
535                 goto nlmsg_failure;
536 
537         nfmsg = nlmsg_data(nlh);
538         nfmsg->nfgen_family = AF_UNSPEC;
539         nfmsg->version = NFNETLINK_V0;
540         nfmsg->res_id = 0;
541 
542         if (nla_put_string(skb, NFCTH_NAME, helper->name))
543                 goto nla_put_failure;
544 
545         if (nla_put_be32(skb, NFCTH_QUEUE_NUM, htonl(helper->queue_num)))
546                 goto nla_put_failure;
547 
548         if (nfnl_cthelper_dump_tuple(skb, helper) < 0)
549                 goto nla_put_failure;
550 
551         if (nfnl_cthelper_dump_policy(skb, helper) < 0)
552                 goto nla_put_failure;
553 
554         if (nla_put_be32(skb, NFCTH_PRIV_DATA_LEN, htonl(helper->data_len)))
555                 goto nla_put_failure;
556 
557         if (helper->flags & NF_CT_HELPER_F_CONFIGURED)
558                 status = NFCT_HELPER_STATUS_ENABLED;
559         else
560                 status = NFCT_HELPER_STATUS_DISABLED;
561 
562         if (nla_put_be32(skb, NFCTH_STATUS, htonl(status)))
563                 goto nla_put_failure;
564 
565         nlmsg_end(skb, nlh);
566         return skb->len;
567 
568 nlmsg_failure:
569 nla_put_failure:
570         nlmsg_cancel(skb, nlh);
571         return -1;
572 }
573 
574 static int
575 nfnl_cthelper_dump_table(struct sk_buff *skb, struct netlink_callback *cb)
576 {
577         struct nf_conntrack_helper *cur, *last;
578 
579         rcu_read_lock();
580         last = (struct nf_conntrack_helper *)cb->args[1];
581         for (; cb->args[0] < nf_ct_helper_hsize; cb->args[0]++) {
582 restart:
583                 hlist_for_each_entry_rcu(cur,
584                                 &nf_ct_helper_hash[cb->args[0]], hnode) {
585 
586                         /* skip non-userspace conntrack helpers. */
587                         if (!(cur->flags & NF_CT_HELPER_F_USERSPACE))
588                                 continue;
589 
590                         if (cb->args[1]) {
591                                 if (cur != last)
592                                         continue;
593                                 cb->args[1] = 0;
594                         }
595                         if (nfnl_cthelper_fill_info(skb,
596                                             NETLINK_CB(cb->skb).portid,
597                                             cb->nlh->nlmsg_seq,
598                                             NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
599                                             NFNL_MSG_CTHELPER_NEW, cur) < 0) {
600                                 cb->args[1] = (unsigned long)cur;
601                                 goto out;
602                         }
603                 }
604         }
605         if (cb->args[1]) {
606                 cb->args[1] = 0;
607                 goto restart;
608         }
609 out:
610         rcu_read_unlock();
611         return skb->len;
612 }
613 
614 static int nfnl_cthelper_get(struct net *net, struct sock *nfnl,
615                              struct sk_buff *skb, const struct nlmsghdr *nlh,
616                              const struct nlattr * const tb[],
617                              struct netlink_ext_ack *extack)
618 {
619         int ret = -ENOENT;
620         struct nf_conntrack_helper *cur;
621         struct sk_buff *skb2;
622         char *helper_name = NULL;
623         struct nf_conntrack_tuple tuple;
624         struct nfnl_cthelper *nlcth;
625         bool tuple_set = false;
626 
627         if (!capable(CAP_NET_ADMIN))
628                 return -EPERM;
629 
630         if (nlh->nlmsg_flags & NLM_F_DUMP) {
631                 struct netlink_dump_control c = {
632                         .dump = nfnl_cthelper_dump_table,
633                 };
634                 return netlink_dump_start(nfnl, skb, nlh, &c);
635         }
636 
637         if (tb[NFCTH_NAME])
638                 helper_name = nla_data(tb[NFCTH_NAME]);
639 
640         if (tb[NFCTH_TUPLE]) {
641                 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
642                 if (ret < 0)
643                         return ret;
644 
645                 tuple_set = true;
646         }
647 
648         list_for_each_entry(nlcth, &nfnl_cthelper_list, list) {
649                 cur = &nlcth->helper;
650                 if (helper_name &&
651                     strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
652                         continue;
653 
654                 if (tuple_set &&
655                     (tuple.src.l3num != cur->tuple.src.l3num ||
656                      tuple.dst.protonum != cur->tuple.dst.protonum))
657                         continue;
658 
659                 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
660                 if (skb2 == NULL) {
661                         ret = -ENOMEM;
662                         break;
663                 }
664 
665                 ret = nfnl_cthelper_fill_info(skb2, NETLINK_CB(skb).portid,
666                                               nlh->nlmsg_seq,
667                                               NFNL_MSG_TYPE(nlh->nlmsg_type),
668                                               NFNL_MSG_CTHELPER_NEW, cur);
669                 if (ret <= 0) {
670                         kfree_skb(skb2);
671                         break;
672                 }
673 
674                 ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
675                                       MSG_DONTWAIT);
676                 if (ret > 0)
677                         ret = 0;
678 
679                 /* this avoids a loop in nfnetlink. */
680                 return ret == -EAGAIN ? -ENOBUFS : ret;
681         }
682         return ret;
683 }
684 
685 static int nfnl_cthelper_del(struct net *net, struct sock *nfnl,
686                              struct sk_buff *skb, const struct nlmsghdr *nlh,
687                              const struct nlattr * const tb[],
688                              struct netlink_ext_ack *extack)
689 {
690         char *helper_name = NULL;
691         struct nf_conntrack_helper *cur;
692         struct nf_conntrack_tuple tuple;
693         bool tuple_set = false, found = false;
694         struct nfnl_cthelper *nlcth, *n;
695         int j = 0, ret;
696 
697         if (!capable(CAP_NET_ADMIN))
698                 return -EPERM;
699 
700         if (tb[NFCTH_NAME])
701                 helper_name = nla_data(tb[NFCTH_NAME]);
702 
703         if (tb[NFCTH_TUPLE]) {
704                 ret = nfnl_cthelper_parse_tuple(&tuple, tb[NFCTH_TUPLE]);
705                 if (ret < 0)
706                         return ret;
707 
708                 tuple_set = true;
709         }
710 
711         ret = -ENOENT;
712         list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
713                 cur = &nlcth->helper;
714                 j++;
715 
716                 if (helper_name &&
717                     strncmp(cur->name, helper_name, NF_CT_HELPER_NAME_LEN))
718                         continue;
719 
720                 if (tuple_set &&
721                     (tuple.src.l3num != cur->tuple.src.l3num ||
722                      tuple.dst.protonum != cur->tuple.dst.protonum))
723                         continue;
724 
725                 if (refcount_dec_if_one(&cur->refcnt)) {
726                         found = true;
727                         nf_conntrack_helper_unregister(cur);
728                         kfree(cur->expect_policy);
729 
730                         list_del(&nlcth->list);
731                         kfree(nlcth);
732                 } else {
733                         ret = -EBUSY;
734                 }
735         }
736 
737         /* Make sure we return success if we flush and there is no helpers */
738         return (found || j == 0) ? 0 : ret;
739 }
740 
741 static const struct nla_policy nfnl_cthelper_policy[NFCTH_MAX+1] = {
742         [NFCTH_NAME] = { .type = NLA_NUL_STRING,
743                          .len = NF_CT_HELPER_NAME_LEN-1 },
744         [NFCTH_QUEUE_NUM] = { .type = NLA_U32, },
745 };
746 
747 static const struct nfnl_callback nfnl_cthelper_cb[NFNL_MSG_CTHELPER_MAX] = {
748         [NFNL_MSG_CTHELPER_NEW]         = { .call = nfnl_cthelper_new,
749                                             .attr_count = NFCTH_MAX,
750                                             .policy = nfnl_cthelper_policy },
751         [NFNL_MSG_CTHELPER_GET]         = { .call = nfnl_cthelper_get,
752                                             .attr_count = NFCTH_MAX,
753                                             .policy = nfnl_cthelper_policy },
754         [NFNL_MSG_CTHELPER_DEL]         = { .call = nfnl_cthelper_del,
755                                             .attr_count = NFCTH_MAX,
756                                             .policy = nfnl_cthelper_policy },
757 };
758 
759 static const struct nfnetlink_subsystem nfnl_cthelper_subsys = {
760         .name                           = "cthelper",
761         .subsys_id                      = NFNL_SUBSYS_CTHELPER,
762         .cb_count                       = NFNL_MSG_CTHELPER_MAX,
763         .cb                             = nfnl_cthelper_cb,
764 };
765 
766 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTHELPER);
767 
768 static int __init nfnl_cthelper_init(void)
769 {
770         int ret;
771 
772         ret = nfnetlink_subsys_register(&nfnl_cthelper_subsys);
773         if (ret < 0) {
774                 pr_err("nfnl_cthelper: cannot register with nfnetlink.\n");
775                 goto err_out;
776         }
777         return 0;
778 err_out:
779         return ret;
780 }
781 
782 static void __exit nfnl_cthelper_exit(void)
783 {
784         struct nf_conntrack_helper *cur;
785         struct nfnl_cthelper *nlcth, *n;
786 
787         nfnetlink_subsys_unregister(&nfnl_cthelper_subsys);
788 
789         list_for_each_entry_safe(nlcth, n, &nfnl_cthelper_list, list) {
790                 cur = &nlcth->helper;
791 
792                 nf_conntrack_helper_unregister(cur);
793                 kfree(cur->expect_policy);
794                 kfree(nlcth);
795         }
796 }
797 
798 module_init(nfnl_cthelper_init);
799 module_exit(nfnl_cthelper_exit);
800 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp