1/*
2 * validator/val_nsec3.h - validator NSEC3 denial of existence functions.
3 *
4 * Copyright (c) 2007, NLnet Labs. All rights reserved.
5 *
6 * This software is open source.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
14 *
15 * Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
17 * and/or other materials provided with the distribution.
18 *
19 * Neither the name of the NLNET LABS nor the names of its contributors may
20 * be used to endorse or promote products derived from this software without
21 * specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36/**
37 * \file
38 *
39 * This file contains helper functions for the validator module.
40 * The functions help with NSEC3 checking, the different NSEC3 proofs
41 * for denial of existence, and proofs for presence of types.
42 *
43 * NSEC3
44 *                      1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
45 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
46 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
47 * |   Hash Alg.   |     Flags     |          Iterations           |
48 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
49 * |  Salt Length  |                     Salt                      /
50 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
51 * |  Hash Length  |             Next Hashed Owner Name            /
52 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
53 * /                         Type Bit Maps                         /
54 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
55 *
56 * NSEC3PARAM
57 *                      1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
58 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
59 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
60 * |   Hash Alg.   |     Flags     |          Iterations           |
61 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
62 * |  Salt Length  |                     Salt                      /
63 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
64 *
65 */
66
67#ifndef VALIDATOR_VAL_NSEC3_H
68#define VALIDATOR_VAL_NSEC3_H
69#include "util/rbtree.h"
70#include "util/data/packed_rrset.h"
71struct val_env;
72struct regional;
73struct module_env;
74struct module_qstate;
75struct ub_packed_rrset_key;
76struct reply_info;
77struct query_info;
78struct key_entry_key;
79struct sldns_buffer;
80
81/**
82 *     0 1 2 3 4 5 6 7
83 *    +-+-+-+-+-+-+-+-+
84 *    |             |O|
85 *    +-+-+-+-+-+-+-+-+
86 * The OPT-OUT bit in the NSEC3 flags field.
87 * If enabled, there can be zero or more unsigned delegations in the span.
88 * If disabled, there are zero unsigned delegations in the span.
89 */
90#define NSEC3_OPTOUT	0x01
91/**
92 * The unknown flags in the NSEC3 flags field.
93 * They must be zero, or the NSEC3 is ignored.
94 */
95#define NSEC3_UNKNOWN_FLAGS 0xFE
96
97/** The SHA1 hash algorithm for NSEC3 */
98#define NSEC3_HASH_SHA1	0x01
99
100/**
101 * Determine if the set of NSEC3 records provided with a response prove NAME
102 * ERROR. This means that the NSEC3s prove a) the closest encloser exists,
103 * b) the direct child of the closest encloser towards qname doesn't exist,
104 * and c) *.closest encloser does not exist.
105 *
106 * @param env: module environment with temporary region and buffer.
107 * @param ve: validator environment, with iteration count settings.
108 * @param list: array of RRsets, some of which are NSEC3s.
109 * @param num: number of RRsets in the array to examine.
110 * @param qinfo: query that is verified for.
111 * @param kkey: key entry that signed the NSEC3s.
112 * @return:
113 * 	sec_status SECURE of the Name Error is proven by the NSEC3 RRs,
114 * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
115 */
116enum sec_status
117nsec3_prove_nameerror(struct module_env* env, struct val_env* ve,
118	struct ub_packed_rrset_key** list, size_t num,
119	struct query_info* qinfo, struct key_entry_key* kkey);
120
121/**
122 * Determine if the NSEC3s provided in a response prove the NOERROR/NODATA
123 * status. There are a number of different variants to this:
124 *
125 * 1) Normal NODATA -- qname is matched to an NSEC3 record, type is not
126 * present.
127 *
128 * 2) ENT NODATA -- because there must be NSEC3 record for
129 * empty-non-terminals, this is the same as #1.
130 *
131 * 3) NSEC3 ownername NODATA -- qname matched an existing, lone NSEC3
132 * ownername, but qtype was not NSEC3. NOTE: as of nsec-05, this case no
133 * longer exists.
134 *
135 * 4) Wildcard NODATA -- A wildcard matched the name, but not the type.
136 *
137 * 5) Opt-In DS NODATA -- the qname is covered by an opt-in span and qtype ==
138 * DS. (or maybe some future record with the same parent-side-only property)
139 *
140 * @param env: module environment with temporary region and buffer.
141 * @param ve: validator environment, with iteration count settings.
142 * @param list: array of RRsets, some of which are NSEC3s.
143 * @param num: number of RRsets in the array to examine.
144 * @param qinfo: query that is verified for.
145 * @param kkey: key entry that signed the NSEC3s.
146 * @return:
147 * 	sec_status SECURE of the proposition is proven by the NSEC3 RRs,
148 * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
149 */
150enum sec_status
151nsec3_prove_nodata(struct module_env* env, struct val_env* ve,
152	struct ub_packed_rrset_key** list, size_t num,
153	struct query_info* qinfo, struct key_entry_key* kkey);
154
155
156/**
157 * Prove that a positive wildcard match was appropriate (no direct match
158 * RRset).
159 *
160 * @param env: module environment with temporary region and buffer.
161 * @param ve: validator environment, with iteration count settings.
162 * @param list: array of RRsets, some of which are NSEC3s.
163 * @param num: number of RRsets in the array to examine.
164 * @param qinfo: query that is verified for.
165 * @param kkey: key entry that signed the NSEC3s.
166 * @param wc: The purported wildcard that matched. This is the wildcard name
167 * 	as *.wildcard.name., with the *. label already removed.
168 * @return:
169 * 	sec_status SECURE of the proposition is proven by the NSEC3 RRs,
170 * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
171 */
172enum sec_status
173nsec3_prove_wildcard(struct module_env* env, struct val_env* ve,
174	struct ub_packed_rrset_key** list, size_t num,
175	struct query_info* qinfo, struct key_entry_key* kkey, uint8_t* wc);
176
177/**
178 * Prove that a DS response either had no DS, or wasn't a delegation point.
179 *
180 * Fundamentally there are two cases here: normal NODATA and Opt-In NODATA.
181 *
182 * @param env: module environment with temporary region and buffer.
183 * @param ve: validator environment, with iteration count settings.
184 * @param list: array of RRsets, some of which are NSEC3s.
185 * @param num: number of RRsets in the array to examine.
186 * @param qinfo: query that is verified for.
187 * @param kkey: key entry that signed the NSEC3s.
188 * @param reason: string for bogus result.
189 * @param qstate: qstate with region.
190 * @return:
191 * 	sec_status SECURE of the proposition is proven by the NSEC3 RRs,
192 * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
193 * 	or if there was no DS in an insecure (i.e., opt-in) way,
194 * 	INDETERMINATE if it was clear that this wasn't a delegation point.
195 */
196enum sec_status
197nsec3_prove_nods(struct module_env* env, struct val_env* ve,
198	struct ub_packed_rrset_key** list, size_t num,
199	struct query_info* qinfo, struct key_entry_key* kkey, char** reason,
200	struct module_qstate* qstate);
201
202/**
203 * Prove NXDOMAIN or NODATA.
204 *
205 * @param env: module environment with temporary region and buffer.
206 * @param ve: validator environment, with iteration count settings.
207 * @param list: array of RRsets, some of which are NSEC3s.
208 * @param num: number of RRsets in the array to examine.
209 * @param qinfo: query that is verified for.
210 * @param kkey: key entry that signed the NSEC3s.
211 * @param nodata: if return value is secure, this indicates if nodata or
212 * 	nxdomain was proven.
213 * @return:
214 * 	sec_status SECURE of the proposition is proven by the NSEC3 RRs,
215 * 	BOGUS if not, INSECURE if all of the NSEC3s could be validly ignored.
216 */
217enum sec_status
218nsec3_prove_nxornodata(struct module_env* env, struct val_env* ve,
219	struct ub_packed_rrset_key** list, size_t num,
220	struct query_info* qinfo, struct key_entry_key* kkey, int* nodata);
221
222/**
223 * The NSEC3 hash result storage.
224 * Consists of an rbtree, with these nodes in it.
225 * The nodes detail how a set of parameters (from nsec3 rr) plus
226 * a dname result in a hash.
227 */
228struct nsec3_cached_hash {
229	/** rbtree node, key is this structure */
230	rbnode_type node;
231	/** where are the parameters for conversion, in this rrset data */
232	struct ub_packed_rrset_key* nsec3;
233	/** where are the parameters for conversion, this RR number in data */
234	int rr;
235	/** the name to convert */
236	uint8_t* dname;
237	/** length of the dname */
238	size_t dname_len;
239	/** the hash result (not base32 encoded) */
240	uint8_t* hash;
241	/** length of hash in bytes */
242	size_t hash_len;
243	/** the hash result in base32 encoding */
244	uint8_t* b32;
245	/** length of base32 encoding (as a label) */
246	size_t b32_len;
247};
248
249/**
250 * Rbtree for hash cache comparison function.
251 * @param c1: key 1.
252 * @param c2: key 2.
253 * @return: comparison code, -1, 0, 1, of the keys.
254 */
255int nsec3_hash_cmp(const void* c1, const void* c2);
256
257/**
258 * Obtain the hash of an owner name.
259 * Used internally by the nsec3 proof functions in this file.
260 * published to enable unit testing of hash algorithms and cache.
261 *
262 * @param table: the cache table. Must be initialised at start.
263 * @param region: scratch region to use for allocation.
264 * 	This region holds the tree, if you wipe the region, reinit the tree.
265 * @param buf: temporary buffer.
266 * @param nsec3: the rrset with parameters
267 * @param rr: rr number from d that has the NSEC3 parameters to hash to.
268 * @param dname: name to hash
269 * 	This pointer is used inside the tree, assumed region-alloced.
270 * @param dname_len: the length of the name.
271 * @param hash: the hash node is returned on success.
272 * @return:
273 * 	1 on success, either from cache or newly hashed hash is returned.
274 * 	0 on a malloc failure.
275 * 	-1 if the NSEC3 rr was badly formatted (i.e. formerr).
276 */
277int nsec3_hash_name(rbtree_type* table, struct regional* region,
278	struct sldns_buffer* buf, struct ub_packed_rrset_key* nsec3, int rr,
279	uint8_t* dname, size_t dname_len, struct nsec3_cached_hash** hash);
280
281/**
282 * Get next owner name, converted to base32 encoding and with the
283 * zone name (taken from the nsec3 owner name) appended.
284 * @param rrset: the NSEC3 rrset.
285 * @param r: the rr num of the nsec3 in the rrset.
286 * @param buf: buffer to store name in
287 * @param max: size of buffer.
288 * @return length of name on success. 0 on failure (buffer too short or
289 *	bad format nsec3 record).
290 */
291size_t nsec3_get_nextowner_b32(struct ub_packed_rrset_key* rrset, int r,
292	uint8_t* buf, size_t max);
293
294/**
295 * Convert hash into base32 encoding and with the
296 * zone name appended.
297 * @param hash: hashed buffer
298 * @param hashlen: length of hash
299 * @param zone: name of zone
300 * @param zonelen: length of zonename.
301 * @param buf: buffer to store name in
302 * @param max: size of buffer.
303 * @return length of name on success. 0 on failure (buffer too short or
304 *	bad format nsec3 record).
305 */
306size_t nsec3_hash_to_b32(uint8_t* hash, size_t hashlen, uint8_t* zone,
307	size_t zonelen, uint8_t* buf, size_t max);
308
309/**
310 * Get NSEC3 parameters out of rr.
311 * @param rrset: the NSEC3 rrset.
312 * @param r: the rr num of the nsec3 in the rrset.
313 * @param algo: nsec3 hash algo.
314 * @param iter: iteration count.
315 * @param salt: ptr to salt inside rdata.
316 * @param saltlen: length of salt.
317 * @return 0 if bad formatted, unknown nsec3 hash algo, or unknown flags set.
318 */
319int nsec3_get_params(struct ub_packed_rrset_key* rrset, int r,
320	int* algo, size_t* iter, uint8_t** salt, size_t* saltlen);
321
322/**
323 * Get NSEC3 hashed in a buffer
324 * @param buf: buffer for temp use.
325 * @param nm: name to hash
326 * @param nmlen: length of nm.
327 * @param algo: algo to use, must be known.
328 * @param iter: iterations
329 * @param salt: salt for nsec3
330 * @param saltlen: length of salt.
331 * @param res: result of hash stored here.
332 * @param max: maximum space for result.
333 * @return 0 on failure, otherwise bytelength stored.
334 */
335size_t nsec3_get_hashed(struct sldns_buffer* buf, uint8_t* nm, size_t nmlen,
336	int algo, size_t iter, uint8_t* salt, size_t saltlen, uint8_t* res,
337	size_t max);
338
339/**
340 * see if NSEC3 RR contains given type
341 * @param rrset: NSEC3 rrset
342 * @param r: RR in rrset
343 * @param type: in host order to check bit for.
344 * @return true if bit set, false if not or error.
345 */
346int nsec3_has_type(struct ub_packed_rrset_key* rrset, int r, uint16_t type);
347
348/**
349 * return if nsec3 RR has the optout flag
350 * @param rrset: NSEC3 rrset
351 * @param r: RR in rrset
352 * @return true if optout, false on error or not optout
353 */
354int nsec3_has_optout(struct ub_packed_rrset_key* rrset, int r);
355
356/**
357 * Return nsec3 RR next hashed owner name
358 * @param rrset: NSEC3 rrset
359 * @param r: RR in rrset
360 * @param next: ptr into rdata to next owner hash
361 * @param nextlen: length of hash.
362 * @return false on malformed
363 */
364int nsec3_get_nextowner(struct ub_packed_rrset_key* rrset, int r,
365	uint8_t** next, size_t* nextlen);
366
367/**
368 * nsec3Covers
369 * Given a hash and a candidate NSEC3Record, determine if that NSEC3Record
370 * covers the hash. Covers specifically means that the hash is in between
371 * the owner and next hashes and does not equal either.
372 *
373 * @param zone: the zone name.
374 * @param hash: the hash of the name
375 * @param rrset: the rrset of the NSEC3.
376 * @param rr: which rr in the rrset.
377 * @param buf: temporary buffer.
378 * @return true if covers, false if not.
379 */
380int nsec3_covers(uint8_t* zone, struct nsec3_cached_hash* hash,
381	struct ub_packed_rrset_key* rrset, int rr, struct sldns_buffer* buf);
382
383#endif /* VALIDATOR_VAL_NSEC3_H */
384