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-rw-r--r--lib/dnssec/nsec3.c734
1 files changed, 734 insertions, 0 deletions
diff --git a/lib/dnssec/nsec3.c b/lib/dnssec/nsec3.c
new file mode 100644
index 0000000..4199f25
--- /dev/null
+++ b/lib/dnssec/nsec3.c
@@ -0,0 +1,734 @@
+/* Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include <string.h>
+
+#include <libdnssec/binary.h>
+#include <libdnssec/error.h>
+#include <libdnssec/nsec.h>
+#include <libknot/descriptor.h>
+#include <contrib/base32hex.h>
+#include <libknot/rrset.h>
+#include <libknot/rrtype/nsec3.h>
+
+#include "lib/defines.h"
+#include "lib/dnssec/nsec.h"
+#include "lib/dnssec/nsec3.h"
+#include "lib/utils.h"
+
+#define OPT_OUT_BIT 0x01
+
+//#define FLG_CLOSEST_ENCLOSER (1 << 0)
+#define FLG_CLOSEST_PROVABLE_ENCLOSER (1 << 1)
+#define FLG_NAME_COVERED (1 << 2)
+#define FLG_NAME_MATCHED (1 << 3)
+#define FLG_TYPE_BIT_MISSING (1 << 4)
+#define FLG_CNAME_BIT_MISSING (1 << 5)
+
+/**
+ * Obtains NSEC3 parameters from RR.
+ * @param params NSEC3 parameters structure to be set.
+ * @param nsec3 NSEC3 RR containing the parameters.
+ * @return 0 or error code.
+ */
+static int nsec3_parameters(dnssec_nsec3_params_t *params, const knot_rrset_t *nsec3)
+{
+ if (kr_fails_assert(params && nsec3))
+ return kr_error(EINVAL);
+
+ const knot_rdata_t *rr = knot_rdataset_at(&nsec3->rrs, 0);
+ if (kr_fails_assert(rr))
+ return kr_error(EINVAL);
+
+ /* Every NSEC3 RR contains data from NSEC3PARAMS. */
+ const size_t SALT_OFFSET = 5; /* First 5 octets contain { Alg, Flags, Iterations, Salt length } */
+ dnssec_binary_t rdata = {
+ .size = SALT_OFFSET + (size_t)knot_nsec3_salt_len(nsec3->rrs.rdata),
+ .data = /*const-cast*/(uint8_t *)rr->data,
+ };
+ if (rdata.size > rr->len)
+ return kr_error(EMSGSIZE);
+
+ int ret = dnssec_nsec3_params_from_rdata(params, &rdata);
+ if (ret != DNSSEC_EOK)
+ return kr_error(EINVAL);
+
+ return kr_ok();
+}
+
+/**
+ * Computes a hash of a given domain name.
+ * @param hash Resulting hash, must be freed.
+ * @param params NSEC3 parameters.
+ * @param name Domain name to be hashed.
+ * @return 0 or error code.
+ */
+static int hash_name(dnssec_binary_t *hash, const dnssec_nsec3_params_t *params,
+ const knot_dname_t *name)
+{
+ if (kr_fails_assert(hash && params))
+ return kr_error(EINVAL);
+ if (!name)
+ return kr_error(EINVAL);
+ if (kr_fails_assert(!kr_nsec3_limited_params(params))) {
+ /* This if is mainly defensive; it shouldn't happen. */
+ return kr_error(EINVAL);
+ }
+
+ dnssec_binary_t dname = {
+ .size = knot_dname_size(name),
+ .data = (uint8_t *) name,
+ };
+
+ int ret = dnssec_nsec3_hash(&dname, params, hash);
+ if (ret != DNSSEC_EOK) {
+ return kr_error(EINVAL);
+ }
+
+ return kr_ok();
+}
+
+/**
+ * Read hash from NSEC3 owner name and store its binary form.
+ * @param hash Buffer to be written.
+ * @param max_hash_size Maximal has size.
+ * @param nsec3 NSEC3 RR.
+ * @return 0 or error code.
+ */
+static int read_owner_hash(dnssec_binary_t *hash, size_t max_hash_size, const knot_rrset_t *nsec3)
+{
+ if (kr_fails_assert(hash && nsec3 && hash->data))
+ return kr_error(EINVAL);
+
+ int32_t ret = base32hex_decode(nsec3->owner + 1, nsec3->owner[0], hash->data, max_hash_size);
+ if (ret < 0)
+ return kr_error(EILSEQ);
+ hash->size = ret;
+
+ return kr_ok();
+}
+
+#define MAX_HASH_BYTES 64
+/**
+ * Closest (provable) encloser match (RFC5155 7.2.1, bullet 1).
+ * @param flags Flags to be set according to check outcome.
+ * @param nsec3 NSEC3 RR.
+ * @param name Name to be checked.
+ * @param skipped Number of skipped labels to find closest (provable) match.
+ * @return 0 or error code.
+ */
+static int closest_encloser_match(int *flags, const knot_rrset_t *nsec3,
+ const knot_dname_t *name, unsigned *skipped)
+{
+ if (kr_fails_assert(flags && nsec3 && name && skipped))
+ return kr_error(EINVAL);
+
+ uint8_t hash_data[MAX_HASH_BYTES] = {0, };
+ dnssec_binary_t owner_hash = { 0, hash_data };
+ dnssec_nsec3_params_t params = { 0, };
+ dnssec_binary_t name_hash = { 0, };
+
+ int ret = read_owner_hash(&owner_hash, MAX_HASH_BYTES, nsec3);
+ if (ret != 0)
+ goto fail;
+
+ ret = nsec3_parameters(&params, nsec3);
+ if (ret != 0)
+ goto fail;
+
+ /* Root label has no encloser */
+ if (!name[0]) {
+ ret = kr_error(ENOENT);
+ goto fail;
+ }
+
+ const knot_dname_t *encloser = knot_wire_next_label(name, NULL);
+ *skipped = 1;
+
+ /* Avoid doing too much work on SHA1, mitigating:
+ * CVE-2023-50868: NSEC3 closest encloser proof can exhaust CPU
+ * We log nothing here; it wouldn't be easy from this place
+ * and huge SNAME should be suspicious on its own.
+ */
+ const int max_labels = knot_dname_labels(nsec3->owner, NULL) - 1
+ + kr_nsec3_max_depth(&params);
+ for (int l = knot_dname_labels(encloser, NULL); l > max_labels; --l) {
+ encloser = knot_wire_next_label(encloser, NULL);
+ ++(*skipped);
+ }
+
+ while(encloser) {
+ ret = hash_name(&name_hash, &params, encloser);
+ if (ret != 0)
+ goto fail;
+
+ if ((owner_hash.size == name_hash.size) &&
+ (memcmp(owner_hash.data, name_hash.data, owner_hash.size) == 0)) {
+ dnssec_binary_free(&name_hash);
+ *flags |= FLG_CLOSEST_PROVABLE_ENCLOSER;
+ break;
+ }
+
+ dnssec_binary_free(&name_hash);
+
+ if (!encloser[0])
+ break;
+ encloser = knot_wire_next_label(encloser, NULL);
+ ++(*skipped);
+ }
+
+ ret = kr_ok();
+
+fail:
+ if (params.salt.data)
+ dnssec_nsec3_params_free(&params);
+ if (name_hash.data)
+ dnssec_binary_free(&name_hash);
+ return ret;
+}
+
+/**
+ * Checks whether NSEC3 RR covers the supplied name (RFC5155 7.2.1, bullet 2).
+ * @param flags Flags to be set according to check outcome.
+ * @param nsec3 NSEC3 RR.
+ * @param name Name to be checked.
+ * @return 0 or error code.
+ */
+static int covers_name(int *flags, const knot_rrset_t *nsec3, const knot_dname_t *name)
+{
+ if (kr_fails_assert(flags && nsec3 && name))
+ return kr_error(EINVAL);
+
+ uint8_t hash_data[MAX_HASH_BYTES] = { 0, };
+ dnssec_binary_t owner_hash = { 0, hash_data };
+ dnssec_nsec3_params_t params = { 0, };
+ dnssec_binary_t name_hash = { 0, };
+
+ int ret = read_owner_hash(&owner_hash, MAX_HASH_BYTES, nsec3);
+ if (ret != 0)
+ goto fail;
+
+ ret = nsec3_parameters(&params, nsec3);
+ if (ret != 0)
+ goto fail;
+
+ ret = hash_name(&name_hash, &params, name);
+ if (ret != 0)
+ goto fail;
+
+ uint8_t next_size = knot_nsec3_next_len(nsec3->rrs.rdata);
+ const uint8_t *next_hash = knot_nsec3_next(nsec3->rrs.rdata);
+
+ if ((next_size > 0) && (owner_hash.size == next_size) && (name_hash.size == next_size)) {
+ /* All hash lengths must be same. */
+ const uint8_t *ownerd = owner_hash.data;
+ const uint8_t *nextd = next_hash;
+ int covered = 0;
+ int greater_then_owner = (memcmp(ownerd, name_hash.data, next_size) < 0);
+ int less_then_next = (memcmp(name_hash.data, nextd, next_size) < 0);
+ if (memcmp(ownerd, nextd, next_size) < 0) {
+ /*
+ * 0 (...) owner ... next (...) MAX
+ * ^
+ * name
+ * ==>
+ * (owner < name) && (name < next)
+ */
+ covered = ((greater_then_owner) && (less_then_next));
+ } else {
+ /*
+ * owner ... MAX, 0 ... next
+ * ^ ^ ^
+ * name name name
+ * =>
+ * (owner < name) || (name < next)
+ */
+ covered = ((greater_then_owner) || (less_then_next));
+ }
+
+ if (covered) {
+ *flags |= FLG_NAME_COVERED;
+
+ uint8_t nsec3_flags = knot_nsec3_flags(nsec3->rrs.rdata);
+ if (nsec3_flags & ~OPT_OUT_BIT) {
+ /* RFC5155 3.1.2 */
+ ret = kr_error(EINVAL);
+ } else {
+ ret = kr_ok();
+ }
+ }
+ }
+
+fail:
+ if (params.salt.data)
+ dnssec_nsec3_params_free(&params);
+ if (name_hash.data)
+ dnssec_binary_free(&name_hash);
+ return ret;
+}
+
+/**
+ * Checks whether NSEC3 RR has the opt-out bit set.
+ * @param flags Flags to be set according to check outcome.
+ * @param nsec3 NSEC3 RR.
+ * @param name Name to be checked.
+ * @return 0 or error code.
+ */
+static bool has_optout(const knot_rrset_t *nsec3)
+{
+ if (!nsec3)
+ return false;
+
+ uint8_t nsec3_flags = knot_nsec3_flags(nsec3->rrs.rdata);
+ if (nsec3_flags & ~OPT_OUT_BIT) {
+ /* RFC5155 3.1.2 */
+ return false;
+ }
+
+ return nsec3_flags & OPT_OUT_BIT;
+}
+
+/**
+ * Checks whether NSEC3 RR matches the supplied name.
+ * @param flags Flags to be set according to check outcome.
+ * @param nsec3 NSEC3 RR.
+ * @param name Name to be checked.
+ * @return 0 if matching, >0 if not (abs(ENOENT)), or error code (<0).
+ */
+static int matches_name(const knot_rrset_t *nsec3, const knot_dname_t *name)
+{
+ if (kr_fails_assert(nsec3 && name))
+ return kr_error(EINVAL);
+
+ uint8_t hash_data[MAX_HASH_BYTES] = { 0, };
+ dnssec_binary_t owner_hash = { 0, hash_data };
+ dnssec_nsec3_params_t params = { 0, };
+ dnssec_binary_t name_hash = { 0, };
+
+ int ret = read_owner_hash(&owner_hash, MAX_HASH_BYTES, nsec3);
+ if (ret != 0)
+ goto fail;
+
+ ret = nsec3_parameters(&params, nsec3);
+ if (ret != 0)
+ goto fail;
+
+ ret = hash_name(&name_hash, &params, name);
+ if (ret != 0)
+ goto fail;
+
+ if ((owner_hash.size == name_hash.size) &&
+ (memcmp(owner_hash.data, name_hash.data, owner_hash.size) == 0)) {
+ ret = kr_ok();
+ } else {
+ ret = abs(ENOENT);
+ }
+
+fail:
+ if (params.salt.data)
+ dnssec_nsec3_params_free(&params);
+ if (name_hash.data)
+ dnssec_binary_free(&name_hash);
+ return ret;
+}
+#undef MAX_HASH_BYTES
+
+/**
+ * Prepends an asterisk label to given name.
+ *
+ * @param tgt Target buffer to write domain name into.
+ * @param name Name to be added to the asterisk.
+ * @return Size of the resulting name or error code.
+ */
+static int prepend_asterisk(uint8_t *tgt, size_t maxlen, const knot_dname_t *name)
+{
+ if (kr_fails_assert(maxlen >= 3))
+ return kr_error(EINVAL);
+ memcpy(tgt, "\1*", 3);
+ return knot_dname_to_wire(tgt + 2, name, maxlen - 2);
+}
+
+/**
+ * Closest encloser proof (RFC5155 7.2.1).
+ * @note No RRSIGs are validated.
+ * @param pkt Packet structure to be processed.
+ * @param section_id Packet section to be processed.
+ * @param sname Name to be checked.
+ * @param encloser_name Returned matching encloser name, if found.
+ * @param matching_encloser_nsec3 Pointer to matching encloser NSEC RRSet.
+ * @param covering_next_nsec3 Pointer to covering next closer NSEC3 RRSet.
+ * @return 0 or error code.
+ */
+static int closest_encloser_proof(const knot_pkt_t *pkt,
+ knot_section_t section_id,
+ const knot_dname_t *sname,
+ const knot_dname_t **encloser_name,
+ const knot_rrset_t **matching_encloser_nsec3,
+ const knot_rrset_t **covering_next_nsec3)
+{
+ const knot_pktsection_t *sec = knot_pkt_section(pkt, section_id);
+ if (!sec || !sname)
+ return kr_error(EINVAL);
+
+ const knot_rrset_t *matching = NULL;
+ const knot_rrset_t *covering = NULL;
+
+ int flags = 0;
+ const knot_dname_t *next_closer = NULL;
+ for (unsigned i = 0; i < sec->count; ++i) {
+ const knot_rrset_t *rrset = knot_pkt_rr(sec, i);
+ if (rrset->type != KNOT_RRTYPE_NSEC3)
+ continue;
+ /* Also skip the NSEC3-to-match an ancestor of sname if it's
+ * a parent-side delegation, as that would mean the owner
+ * does not really exist (authoritatively in this zone,
+ * even in case of opt-out).
+ */
+ const uint8_t *bm = knot_nsec3_bitmap(rrset->rrs.rdata);
+ uint16_t bm_size = knot_nsec3_bitmap_len(rrset->rrs.rdata);
+ if (kr_nsec_children_in_zone_check(bm, bm_size) != 0)
+ continue; /* no fatal errors from bad RRs */
+ /* Match the NSEC3 to sname or one of its ancestors. */
+ unsigned skipped = 0;
+ flags = 0;
+ int ret = closest_encloser_match(&flags, rrset, sname, &skipped);
+ if (ret != 0)
+ return ret;
+ if (!(flags & FLG_CLOSEST_PROVABLE_ENCLOSER))
+ continue;
+ matching = rrset;
+ /* Construct the next closer name and try to cover it. */
+ --skipped;
+ next_closer = sname;
+ for (unsigned j = 0; j < skipped; ++j) {
+ if (kr_fails_assert(next_closer[0]))
+ return kr_error(EINVAL);
+ next_closer = knot_wire_next_label(next_closer, NULL);
+ }
+ for (unsigned j = 0; j < sec->count; ++j) {
+ const knot_rrset_t *rrset_j = knot_pkt_rr(sec, j);
+ if (rrset_j->type != KNOT_RRTYPE_NSEC3)
+ continue;
+ ret = covers_name(&flags, rrset_j, next_closer);
+ if (ret != 0)
+ return ret;
+ if (flags & FLG_NAME_COVERED) {
+ covering = rrset_j;
+ break;
+ }
+ }
+ if (flags & FLG_NAME_COVERED)
+ break;
+ flags = 0; //
+ }
+
+ if ((flags & FLG_CLOSEST_PROVABLE_ENCLOSER) && (flags & FLG_NAME_COVERED) && next_closer) {
+ if (encloser_name && next_closer[0])
+ *encloser_name = knot_wire_next_label(next_closer, NULL);
+ if (matching_encloser_nsec3)
+ *matching_encloser_nsec3 = matching;
+ if (covering_next_nsec3)
+ *covering_next_nsec3 = covering;
+ return kr_ok();
+ }
+
+ return kr_error(ENOENT);
+}
+
+/**
+ * Check whether any NSEC3 RR covers a wildcard RR at the closer encloser.
+ * @param pkt Packet structure to be processed.
+ * @param section_id Packet section to be processed.
+ * @param encloser Closest (provable) encloser domain name.
+ * @return 0 or error code:
+ * KNOT_ERANGE - NSEC3 RR (that covers a wildcard)
+ * has been found, but has opt-out flag set;
+ * otherwise - error.
+ */
+static int covers_closest_encloser_wildcard(const knot_pkt_t *pkt, knot_section_t section_id,
+ const knot_dname_t *encloser)
+{
+ const knot_pktsection_t *sec = knot_pkt_section(pkt, section_id);
+ if (!sec || !encloser)
+ return kr_error(EINVAL);
+
+ uint8_t wildcard[KNOT_DNAME_MAXLEN];
+ wildcard[0] = 1;
+ wildcard[1] = '*';
+ int encloser_len = knot_dname_size(encloser);
+ if (encloser_len < 0)
+ return encloser_len;
+ memcpy(wildcard + 2, encloser, encloser_len);
+
+ int flags = 0;
+ for (unsigned i = 0; i < sec->count; ++i) {
+ const knot_rrset_t *rrset = knot_pkt_rr(sec, i);
+ if (rrset->type != KNOT_RRTYPE_NSEC3)
+ continue;
+ int ret = covers_name(&flags, rrset, wildcard);
+ if (ret != 0)
+ return ret;
+ if (flags & FLG_NAME_COVERED) {
+ return has_optout(rrset) ?
+ kr_error(KNOT_ERANGE) : kr_ok();
+ }
+ }
+
+ return kr_error(ENOENT);
+}
+
+int kr_nsec3_name_error_response_check(const knot_pkt_t *pkt, knot_section_t section_id,
+ const knot_dname_t *sname)
+{
+ const knot_dname_t *encloser = NULL;
+ const knot_rrset_t *covering_next_nsec3 = NULL;
+ int ret = closest_encloser_proof(pkt, section_id, sname,
+ &encloser, NULL, &covering_next_nsec3);
+ if (ret != 0)
+ return ret;
+ ret = covers_closest_encloser_wildcard(pkt, section_id, encloser);
+ if (ret != 0) {
+ /* OK, but NSEC3 for wildcard at encloser has opt-out;
+ * or error */
+ return ret;
+ }
+ /* Closest encloser proof is OK and
+ * NSEC3 for wildcard has been found and optout flag is not set.
+ * Now check if NSEC3 that covers next closer name has opt-out. */
+ return has_optout(covering_next_nsec3) ?
+ kr_error(KNOT_ERANGE) : kr_ok();
+}
+
+/**
+ * Search the packet section for a matching NSEC3 with nodata-proving bitmap.
+ * @param pkt Packet structure to be processed.
+ * @param section_id Packet section to be processed.
+ * @param sname Name to be checked.
+ * @param stype Type to be checked.
+ * @return 0 or error code.
+ * @note This does NOT check the opt-out case if type is DS;
+ * see RFC 5155 8.6.
+ */
+static int nodata_find(const knot_pkt_t *pkt, knot_section_t section_id,
+ const knot_dname_t *name, const uint16_t type)
+{
+ const knot_pktsection_t *sec = knot_pkt_section(pkt, section_id);
+ if (!sec || !name)
+ return kr_error(EINVAL);
+
+ for (unsigned i = 0; i < sec->count; ++i) {
+ const knot_rrset_t *nsec3 = knot_pkt_rr(sec, i);
+ /* Records causing any errors are simply skipped. */
+ if (nsec3->type != KNOT_RRTYPE_NSEC3
+ || matches_name(nsec3, name) != kr_ok()) {
+ continue;
+ /* LATER(optim.): we repeatedly recompute the hash of `name` */
+ }
+
+ const uint8_t *bm = knot_nsec3_bitmap(nsec3->rrs.rdata);
+ uint16_t bm_size = knot_nsec3_bitmap_len(nsec3->rrs.rdata);
+ if (kr_nsec_bitmap_nodata_check(bm, bm_size, type, nsec3->owner) == kr_ok())
+ return kr_ok();
+ }
+
+ return kr_error(ENOENT);
+}
+
+/**
+ * Check whether NSEC3 RR matches a wildcard at the closest encloser and has given type bit missing.
+ * @param pkt Packet structure to be processed.
+ * @param section_id Packet section to be processed.
+ * @param encloser Closest (provable) encloser domain name.
+ * @param stype Type to be checked.
+ * @return 0 or error code.
+ */
+static int matches_closest_encloser_wildcard(const knot_pkt_t *pkt, knot_section_t section_id,
+ const knot_dname_t *encloser, uint16_t stype)
+{
+ const knot_pktsection_t *sec = knot_pkt_section(pkt, section_id);
+ if (!sec || !encloser)
+ return kr_error(EINVAL);
+
+ uint8_t wildcard[KNOT_DNAME_MAXLEN]; /**< the source of synthesis */
+ int ret = prepend_asterisk(wildcard, sizeof(wildcard), encloser);
+ if (ret < 0)
+ return ret;
+ kr_require(ret >= 3);
+ return nodata_find(pkt, section_id, wildcard, stype);
+}
+
+int kr_nsec3_wildcard_answer_response_check(const knot_pkt_t *pkt, knot_section_t section_id,
+ const knot_dname_t *sname, int trim_to_next)
+{
+ const knot_pktsection_t *sec = knot_pkt_section(pkt, section_id);
+ if (!sec || !sname)
+ return kr_error(EINVAL);
+
+ /* Compute the next closer name. */
+ for (int i = 0; i < trim_to_next; ++i) {
+ if (kr_fails_assert(sname[0]))
+ return kr_error(EINVAL);
+ sname = knot_wire_next_label(sname, NULL);
+ }
+
+ int flags = 0;
+ for (unsigned i = 0; i < sec->count; ++i) {
+ const knot_rrset_t *rrset = knot_pkt_rr(sec, i);
+ if (rrset->type != KNOT_RRTYPE_NSEC3)
+ continue;
+ if (kr_nsec3_limited_rdata(rrset->rrs.rdata)) {
+ /* Avoid hashing with too many iterations.
+ * If we get here, the `sname` wildcard probably ends up bogus,
+ * but it gets downgraded to KR_RANK_INSECURE when validator
+ * gets to verifying one of these over-limit NSEC3 RRs. */
+ continue;
+ }
+ int ret = covers_name(&flags, rrset, sname);
+ if (ret != 0)
+ return ret;
+ if (flags & FLG_NAME_COVERED) {
+ return has_optout(rrset) ?
+ kr_error(KNOT_ERANGE) : kr_ok();
+ }
+ }
+
+ return kr_error(ENOENT);
+}
+
+
+int kr_nsec3_no_data(const knot_pkt_t *pkt, knot_section_t section_id,
+ const knot_dname_t *sname, uint16_t stype)
+{
+ /* DS record may be also matched by an existing NSEC3 RR. */
+ int ret = nodata_find(pkt, section_id, sname, stype);
+ if (ret == 0) {
+ /* Satisfies RFC5155 8.5 and 8.6, both first paragraph. */
+ return ret;
+ }
+
+ /* Find closest provable encloser. */
+ const knot_dname_t *encloser_name = NULL;
+ const knot_rrset_t *covering_next_nsec3 = NULL;
+ ret = closest_encloser_proof(pkt, section_id, sname, &encloser_name,
+ NULL, &covering_next_nsec3);
+ if (ret != 0)
+ return ret;
+
+ if (kr_fails_assert(encloser_name && covering_next_nsec3))
+ return kr_error(EFAULT);
+ ret = matches_closest_encloser_wildcard(pkt, section_id,
+ encloser_name, stype);
+ if (ret == 0) {
+ /* Satisfies RFC5155 8.7 */
+ if (has_optout(covering_next_nsec3)) {
+ /* Opt-out is detected.
+ * Despite the fact that all records
+ * in the packet can be properly signed,
+ * AD bit must not be set due to rfc5155 9.2.
+ * Return appropriate code to the caller */
+ ret = kr_error(KNOT_ERANGE);
+ }
+ return ret;
+ }
+
+ if (!has_optout(covering_next_nsec3)) {
+ /* Bogus */
+ ret = kr_error(ENOENT);
+ } else {
+ /*
+ * Satisfies RFC5155 8.6 (QTYPE == DS), 2nd paragraph.
+ * Also satisfies ERRATA 3441 8.5 (QTYPE != DS), 3rd paragraph.
+ * - (wildcard) empty nonterminal
+ * derived from insecure delegation.
+ * Denial of existence can not be proven.
+ * Set error code to proceed insecure.
+ */
+ ret = kr_error(KNOT_ERANGE);
+ }
+
+ return ret;
+}
+
+int kr_nsec3_ref_to_unsigned(const knot_pkt_t *pkt)
+{
+ const knot_pktsection_t *sec = knot_pkt_section(pkt, KNOT_AUTHORITY);
+ if (!sec)
+ return kr_error(EINVAL);
+ for (unsigned i = 0; i < sec->count; ++i) {
+ const knot_rrset_t *ns = knot_pkt_rr(sec, i);
+ if (ns->type == KNOT_RRTYPE_DS)
+ return kr_error(EEXIST);
+ if (ns->type != KNOT_RRTYPE_NS)
+ continue;
+
+ bool nsec3_found = false;
+ for (unsigned j = 0; j < sec->count; ++j) {
+ const knot_rrset_t *nsec3 = knot_pkt_rr(sec, j);
+ if (nsec3->type == KNOT_RRTYPE_DS)
+ return kr_error(EEXIST);
+ if (nsec3->type != KNOT_RRTYPE_NSEC3)
+ continue;
+ nsec3_found = true;
+ /* nsec3 found, check if owner name matches the delegation name.
+ * Just skip in case of *any* errors. */
+ if (matches_name(nsec3, ns->owner) != kr_ok())
+ continue;
+
+ const uint8_t *bm = knot_nsec3_bitmap(nsec3->rrs.rdata);
+ uint16_t bm_size = knot_nsec3_bitmap_len(nsec3->rrs.rdata);
+ if (!bm)
+ return kr_error(EINVAL);
+ if (dnssec_nsec_bitmap_contains(bm, bm_size,
+ KNOT_RRTYPE_NS) &&
+ !dnssec_nsec_bitmap_contains(bm, bm_size,
+ KNOT_RRTYPE_DS) &&
+ !dnssec_nsec_bitmap_contains(bm, bm_size,
+ KNOT_RRTYPE_SOA)) {
+ /* Satisfies rfc5155, 8.9. paragraph 2 */
+ return kr_ok();
+ }
+ }
+ if (!nsec3_found)
+ return kr_error(DNSSEC_NOT_FOUND);
+ /* nsec3 that matches the delegation was not found.
+ * Check rfc5155, 8.9. paragraph 4.
+ * Find closest provable encloser.
+ */
+ const knot_dname_t *encloser_name = NULL;
+ const knot_rrset_t *covering_next_nsec3 = NULL;
+ int ret = closest_encloser_proof(pkt, KNOT_AUTHORITY, ns->owner,
+ &encloser_name, NULL, &covering_next_nsec3);
+ if (ret != 0)
+ return kr_error(EINVAL);
+
+ if (has_optout(covering_next_nsec3)) {
+ return kr_error(KNOT_ERANGE);
+ } else {
+ return kr_error(EINVAL);
+ }
+ }
+ return kr_error(EINVAL);
+}
+
+int kr_nsec3_matches_name_and_type(const knot_rrset_t *nsec3,
+ const knot_dname_t *name, uint16_t type)
+{
+ /* It's not secure enough to just check a single bit for (some) other types,
+ * but we don't (currently) only use this API for NS. See RFC 6840 sec. 4.
+ */
+ if (kr_fails_assert(type == KNOT_RRTYPE_NS))
+ return kr_error(EINVAL);
+ int ret = matches_name(nsec3, name);
+ if (ret)
+ return kr_error(ret);
+ const uint8_t *bm = knot_nsec3_bitmap(nsec3->rrs.rdata);
+ uint16_t bm_size = knot_nsec3_bitmap_len(nsec3->rrs.rdata);
+ if (!bm)
+ return kr_error(EINVAL);
+ if (dnssec_nsec_bitmap_contains(bm, bm_size, type)) {
+ return kr_ok();
+ } else {
+ return kr_error(ENOENT);
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 13:23:47 +0000