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

TOMOYO Linux Cross Reference
Linux/net/ipv6/seg6_hmac.c

Version: ~ [ linux-5.12-rc6 ] ~ [ linux-5.11.13 ] ~ [ linux-5.10.29 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.111 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.186 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.230 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.266 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.266 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ 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 /*
  2  *  SR-IPv6 implementation -- HMAC functions
  3  *
  4  *  Author:
  5  *  David Lebrun <david.lebrun@uclouvain.be>
  6  *
  7  *
  8  *  This program is free software; you can redistribute it and/or
  9  *      modify it under the terms of the GNU General Public License
 10  *      as published by the Free Software Foundation; either version
 11  *      2 of the License, or (at your option) any later version.
 12  */
 13 
 14 #include <linux/errno.h>
 15 #include <linux/kernel.h>
 16 #include <linux/types.h>
 17 #include <linux/socket.h>
 18 #include <linux/sockios.h>
 19 #include <linux/net.h>
 20 #include <linux/netdevice.h>
 21 #include <linux/in6.h>
 22 #include <linux/icmpv6.h>
 23 #include <linux/mroute6.h>
 24 #include <linux/slab.h>
 25 #include <linux/rhashtable.h>
 26 
 27 #include <linux/netfilter.h>
 28 #include <linux/netfilter_ipv6.h>
 29 
 30 #include <net/sock.h>
 31 #include <net/snmp.h>
 32 
 33 #include <net/ipv6.h>
 34 #include <net/protocol.h>
 35 #include <net/transp_v6.h>
 36 #include <net/rawv6.h>
 37 #include <net/ndisc.h>
 38 #include <net/ip6_route.h>
 39 #include <net/addrconf.h>
 40 #include <net/xfrm.h>
 41 
 42 #include <linux/cryptohash.h>
 43 #include <crypto/hash.h>
 44 #include <crypto/sha.h>
 45 #include <net/seg6.h>
 46 #include <net/genetlink.h>
 47 #include <net/seg6_hmac.h>
 48 #include <linux/random.h>
 49 
 50 static DEFINE_PER_CPU(char [SEG6_HMAC_RING_SIZE], hmac_ring);
 51 
 52 static int seg6_hmac_cmpfn(struct rhashtable_compare_arg *arg, const void *obj)
 53 {
 54         const struct seg6_hmac_info *hinfo = obj;
 55 
 56         return (hinfo->hmackeyid != *(__u32 *)arg->key);
 57 }
 58 
 59 static inline void seg6_hinfo_release(struct seg6_hmac_info *hinfo)
 60 {
 61         kfree_rcu(hinfo, rcu);
 62 }
 63 
 64 static void seg6_free_hi(void *ptr, void *arg)
 65 {
 66         struct seg6_hmac_info *hinfo = (struct seg6_hmac_info *)ptr;
 67 
 68         if (hinfo)
 69                 seg6_hinfo_release(hinfo);
 70 }
 71 
 72 static const struct rhashtable_params rht_params = {
 73         .head_offset            = offsetof(struct seg6_hmac_info, node),
 74         .key_offset             = offsetof(struct seg6_hmac_info, hmackeyid),
 75         .key_len                = sizeof(u32),
 76         .automatic_shrinking    = true,
 77         .obj_cmpfn              = seg6_hmac_cmpfn,
 78 };
 79 
 80 static struct seg6_hmac_algo hmac_algos[] = {
 81         {
 82                 .alg_id = SEG6_HMAC_ALGO_SHA1,
 83                 .name = "hmac(sha1)",
 84         },
 85         {
 86                 .alg_id = SEG6_HMAC_ALGO_SHA256,
 87                 .name = "hmac(sha256)",
 88         },
 89 };
 90 
 91 static struct sr6_tlv_hmac *seg6_get_tlv_hmac(struct ipv6_sr_hdr *srh)
 92 {
 93         struct sr6_tlv_hmac *tlv;
 94 
 95         if (srh->hdrlen < (srh->first_segment + 1) * 2 + 5)
 96                 return NULL;
 97 
 98         if (!sr_has_hmac(srh))
 99                 return NULL;
100 
101         tlv = (struct sr6_tlv_hmac *)
102               ((char *)srh + ((srh->hdrlen + 1) << 3) - 40);
103 
104         if (tlv->tlvhdr.type != SR6_TLV_HMAC || tlv->tlvhdr.len != 38)
105                 return NULL;
106 
107         return tlv;
108 }
109 
110 static struct seg6_hmac_algo *__hmac_get_algo(u8 alg_id)
111 {
112         struct seg6_hmac_algo *algo;
113         int i, alg_count;
114 
115         alg_count = ARRAY_SIZE(hmac_algos);
116         for (i = 0; i < alg_count; i++) {
117                 algo = &hmac_algos[i];
118                 if (algo->alg_id == alg_id)
119                         return algo;
120         }
121 
122         return NULL;
123 }
124 
125 static int __do_hmac(struct seg6_hmac_info *hinfo, const char *text, u8 psize,
126                      u8 *output, int outlen)
127 {
128         struct seg6_hmac_algo *algo;
129         struct crypto_shash *tfm;
130         struct shash_desc *shash;
131         int ret, dgsize;
132 
133         algo = __hmac_get_algo(hinfo->alg_id);
134         if (!algo)
135                 return -ENOENT;
136 
137         tfm = *this_cpu_ptr(algo->tfms);
138 
139         dgsize = crypto_shash_digestsize(tfm);
140         if (dgsize > outlen) {
141                 pr_debug("sr-ipv6: __do_hmac: digest size too big (%d / %d)\n",
142                          dgsize, outlen);
143                 return -ENOMEM;
144         }
145 
146         ret = crypto_shash_setkey(tfm, hinfo->secret, hinfo->slen);
147         if (ret < 0) {
148                 pr_debug("sr-ipv6: crypto_shash_setkey failed: err %d\n", ret);
149                 goto failed;
150         }
151 
152         shash = *this_cpu_ptr(algo->shashs);
153         shash->tfm = tfm;
154 
155         ret = crypto_shash_digest(shash, text, psize, output);
156         if (ret < 0) {
157                 pr_debug("sr-ipv6: crypto_shash_digest failed: err %d\n", ret);
158                 goto failed;
159         }
160 
161         return dgsize;
162 
163 failed:
164         return ret;
165 }
166 
167 int seg6_hmac_compute(struct seg6_hmac_info *hinfo, struct ipv6_sr_hdr *hdr,
168                       struct in6_addr *saddr, u8 *output)
169 {
170         __be32 hmackeyid = cpu_to_be32(hinfo->hmackeyid);
171         u8 tmp_out[SEG6_HMAC_MAX_DIGESTSIZE];
172         int plen, i, dgsize, wrsize;
173         char *ring, *off;
174 
175         /* a 160-byte buffer for digest output allows to store highest known
176          * hash function (RadioGatun) with up to 1216 bits
177          */
178 
179         /* saddr(16) + first_seg(1) + flags(1) + keyid(4) + seglist(16n) */
180         plen = 16 + 1 + 1 + 4 + (hdr->first_segment + 1) * 16;
181 
182         /* this limit allows for 14 segments */
183         if (plen >= SEG6_HMAC_RING_SIZE)
184                 return -EMSGSIZE;
185 
186         /* Let's build the HMAC text on the ring buffer. The text is composed
187          * as follows, in order:
188          *
189          * 1. Source IPv6 address (128 bits)
190          * 2. first_segment value (8 bits)
191          * 3. Flags (8 bits)
192          * 4. HMAC Key ID (32 bits)
193          * 5. All segments in the segments list (n * 128 bits)
194          */
195 
196         local_bh_disable();
197         ring = this_cpu_ptr(hmac_ring);
198         off = ring;
199 
200         /* source address */
201         memcpy(off, saddr, 16);
202         off += 16;
203 
204         /* first_segment value */
205         *off++ = hdr->first_segment;
206 
207         /* flags */
208         *off++ = hdr->flags;
209 
210         /* HMAC Key ID */
211         memcpy(off, &hmackeyid, 4);
212         off += 4;
213 
214         /* all segments in the list */
215         for (i = 0; i < hdr->first_segment + 1; i++) {
216                 memcpy(off, hdr->segments + i, 16);
217                 off += 16;
218         }
219 
220         dgsize = __do_hmac(hinfo, ring, plen, tmp_out,
221                            SEG6_HMAC_MAX_DIGESTSIZE);
222         local_bh_enable();
223 
224         if (dgsize < 0)
225                 return dgsize;
226 
227         wrsize = SEG6_HMAC_FIELD_LEN;
228         if (wrsize > dgsize)
229                 wrsize = dgsize;
230 
231         memset(output, 0, SEG6_HMAC_FIELD_LEN);
232         memcpy(output, tmp_out, wrsize);
233 
234         return 0;
235 }
236 EXPORT_SYMBOL(seg6_hmac_compute);
237 
238 /* checks if an incoming SR-enabled packet's HMAC status matches
239  * the incoming policy.
240  *
241  * called with rcu_read_lock()
242  */
243 bool seg6_hmac_validate_skb(struct sk_buff *skb)
244 {
245         u8 hmac_output[SEG6_HMAC_FIELD_LEN];
246         struct net *net = dev_net(skb->dev);
247         struct seg6_hmac_info *hinfo;
248         struct sr6_tlv_hmac *tlv;
249         struct ipv6_sr_hdr *srh;
250         struct inet6_dev *idev;
251 
252         idev = __in6_dev_get(skb->dev);
253 
254         srh = (struct ipv6_sr_hdr *)skb_transport_header(skb);
255 
256         tlv = seg6_get_tlv_hmac(srh);
257 
258         /* mandatory check but no tlv */
259         if (idev->cnf.seg6_require_hmac > 0 && !tlv)
260                 return false;
261 
262         /* no check */
263         if (idev->cnf.seg6_require_hmac < 0)
264                 return true;
265 
266         /* check only if present */
267         if (idev->cnf.seg6_require_hmac == 0 && !tlv)
268                 return true;
269 
270         /* now, seg6_require_hmac >= 0 && tlv */
271 
272         hinfo = seg6_hmac_info_lookup(net, be32_to_cpu(tlv->hmackeyid));
273         if (!hinfo)
274                 return false;
275 
276         if (seg6_hmac_compute(hinfo, srh, &ipv6_hdr(skb)->saddr, hmac_output))
277                 return false;
278 
279         if (memcmp(hmac_output, tlv->hmac, SEG6_HMAC_FIELD_LEN) != 0)
280                 return false;
281 
282         return true;
283 }
284 EXPORT_SYMBOL(seg6_hmac_validate_skb);
285 
286 /* called with rcu_read_lock() */
287 struct seg6_hmac_info *seg6_hmac_info_lookup(struct net *net, u32 key)
288 {
289         struct seg6_pernet_data *sdata = seg6_pernet(net);
290         struct seg6_hmac_info *hinfo;
291 
292         hinfo = rhashtable_lookup_fast(&sdata->hmac_infos, &key, rht_params);
293 
294         return hinfo;
295 }
296 EXPORT_SYMBOL(seg6_hmac_info_lookup);
297 
298 int seg6_hmac_info_add(struct net *net, u32 key, struct seg6_hmac_info *hinfo)
299 {
300         struct seg6_pernet_data *sdata = seg6_pernet(net);
301         int err;
302 
303         err = rhashtable_lookup_insert_fast(&sdata->hmac_infos, &hinfo->node,
304                                             rht_params);
305 
306         return err;
307 }
308 EXPORT_SYMBOL(seg6_hmac_info_add);
309 
310 int seg6_hmac_info_del(struct net *net, u32 key)
311 {
312         struct seg6_pernet_data *sdata = seg6_pernet(net);
313         struct seg6_hmac_info *hinfo;
314         int err = -ENOENT;
315 
316         hinfo = rhashtable_lookup_fast(&sdata->hmac_infos, &key, rht_params);
317         if (!hinfo)
318                 goto out;
319 
320         err = rhashtable_remove_fast(&sdata->hmac_infos, &hinfo->node,
321                                      rht_params);
322         if (err)
323                 goto out;
324 
325         seg6_hinfo_release(hinfo);
326 
327 out:
328         return err;
329 }
330 EXPORT_SYMBOL(seg6_hmac_info_del);
331 
332 int seg6_push_hmac(struct net *net, struct in6_addr *saddr,
333                    struct ipv6_sr_hdr *srh)
334 {
335         struct seg6_hmac_info *hinfo;
336         struct sr6_tlv_hmac *tlv;
337         int err = -ENOENT;
338 
339         tlv = seg6_get_tlv_hmac(srh);
340         if (!tlv)
341                 return -EINVAL;
342 
343         rcu_read_lock();
344 
345         hinfo = seg6_hmac_info_lookup(net, be32_to_cpu(tlv->hmackeyid));
346         if (!hinfo)
347                 goto out;
348 
349         memset(tlv->hmac, 0, SEG6_HMAC_FIELD_LEN);
350         err = seg6_hmac_compute(hinfo, srh, saddr, tlv->hmac);
351 
352 out:
353         rcu_read_unlock();
354         return err;
355 }
356 EXPORT_SYMBOL(seg6_push_hmac);
357 
358 static int seg6_hmac_init_algo(void)
359 {
360         struct seg6_hmac_algo *algo;
361         struct crypto_shash *tfm;
362         struct shash_desc *shash;
363         int i, alg_count, cpu;
364 
365         alg_count = ARRAY_SIZE(hmac_algos);
366 
367         for (i = 0; i < alg_count; i++) {
368                 struct crypto_shash **p_tfm;
369                 int shsize;
370 
371                 algo = &hmac_algos[i];
372                 algo->tfms = alloc_percpu(struct crypto_shash *);
373                 if (!algo->tfms)
374                         return -ENOMEM;
375 
376                 for_each_possible_cpu(cpu) {
377                         tfm = crypto_alloc_shash(algo->name, 0, 0);
378                         if (IS_ERR(tfm))
379                                 return PTR_ERR(tfm);
380                         p_tfm = per_cpu_ptr(algo->tfms, cpu);
381                         *p_tfm = tfm;
382                 }
383 
384                 p_tfm = raw_cpu_ptr(algo->tfms);
385                 tfm = *p_tfm;
386 
387                 shsize = sizeof(*shash) + crypto_shash_descsize(tfm);
388 
389                 algo->shashs = alloc_percpu(struct shash_desc *);
390                 if (!algo->shashs)
391                         return -ENOMEM;
392 
393                 for_each_possible_cpu(cpu) {
394                         shash = kzalloc_node(shsize, GFP_KERNEL,
395                                              cpu_to_node(cpu));
396                         if (!shash)
397                                 return -ENOMEM;
398                         *per_cpu_ptr(algo->shashs, cpu) = shash;
399                 }
400         }
401 
402         return 0;
403 }
404 
405 int __init seg6_hmac_init(void)
406 {
407         return seg6_hmac_init_algo();
408 }
409 EXPORT_SYMBOL(seg6_hmac_init);
410 
411 int __net_init seg6_hmac_net_init(struct net *net)
412 {
413         struct seg6_pernet_data *sdata = seg6_pernet(net);
414 
415         rhashtable_init(&sdata->hmac_infos, &rht_params);
416 
417         return 0;
418 }
419 EXPORT_SYMBOL(seg6_hmac_net_init);
420 
421 void seg6_hmac_exit(void)
422 {
423         struct seg6_hmac_algo *algo = NULL;
424         int i, alg_count, cpu;
425 
426         alg_count = ARRAY_SIZE(hmac_algos);
427         for (i = 0; i < alg_count; i++) {
428                 algo = &hmac_algos[i];
429                 for_each_possible_cpu(cpu) {
430                         struct crypto_shash *tfm;
431                         struct shash_desc *shash;
432 
433                         shash = *per_cpu_ptr(algo->shashs, cpu);
434                         kfree(shash);
435                         tfm = *per_cpu_ptr(algo->tfms, cpu);
436                         crypto_free_shash(tfm);
437                 }
438                 free_percpu(algo->tfms);
439                 free_percpu(algo->shashs);
440         }
441 }
442 EXPORT_SYMBOL(seg6_hmac_exit);
443 
444 void __net_exit seg6_hmac_net_exit(struct net *net)
445 {
446         struct seg6_pernet_data *sdata = seg6_pernet(net);
447 
448         rhashtable_free_and_destroy(&sdata->hmac_infos, seg6_free_hi, NULL);
449 }
450 EXPORT_SYMBOL(seg6_hmac_net_exit);
451 

~ [ 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