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-rw-r--r--src/resolve/resolved-dns-answer.c1
-rw-r--r--src/resolve/resolved-dns-dnssec.c183
-rw-r--r--src/resolve/resolved-dns-dnssec.h15
-rw-r--r--src/resolve/resolved-dns-transaction.c53
-rw-r--r--src/resolve/test-dnssec.c35
5 files changed, 285 insertions, 2 deletions
diff --git a/src/resolve/resolved-dns-answer.c b/src/resolve/resolved-dns-answer.c
index 6a37345e7e..5355303bd3 100644
--- a/src/resolve/resolved-dns-answer.c
+++ b/src/resolve/resolved-dns-answer.c
@@ -22,6 +22,7 @@
#include "alloc-util.h"
#include "dns-domain.h"
#include "resolved-dns-answer.h"
+#include "resolved-dns-dnssec.h"
#include "string-util.h"
DnsAnswer *dns_answer_new(unsigned n) {
diff --git a/src/resolve/resolved-dns-dnssec.c b/src/resolve/resolved-dns-dnssec.c
index 9eb54d44db..d7d50c164c 100644
--- a/src/resolve/resolved-dns-dnssec.c
+++ b/src/resolve/resolved-dns-dnssec.c
@@ -23,6 +23,7 @@
#include "alloc-util.h"
#include "dns-domain.h"
+#include "hexdecoct.h"
#include "resolved-dns-dnssec.h"
#include "resolved-dns-packet.h"
#include "string-table.h"
@@ -795,6 +796,187 @@ int dnssec_verify_dnskey_search(DnsResourceRecord *dnskey, DnsAnswer *validated_
return 0;
}
+int dnssec_nsec3_hash(DnsResourceRecord *nsec3, const char *name, void *ret) {
+ uint8_t wire_format[DNS_WIRE_FOMAT_HOSTNAME_MAX];
+ gcry_md_hd_t md = NULL;
+ size_t hash_size;
+ int algorithm;
+ void *result;
+ unsigned k;
+ int r;
+
+ assert(nsec3);
+ assert(name);
+ assert(ret);
+
+ if (nsec3->key->type != DNS_TYPE_NSEC3)
+ return -EINVAL;
+
+ algorithm = digest_to_gcrypt(nsec3->nsec3.algorithm);
+ if (algorithm < 0)
+ return algorithm;
+
+ initialize_libgcrypt();
+
+ hash_size = gcry_md_get_algo_dlen(algorithm);
+ assert(hash_size > 0);
+
+ if (nsec3->nsec3.next_hashed_name_size != hash_size)
+ return -EINVAL;
+
+ r = dns_name_to_wire_format(name, wire_format, sizeof(wire_format), true);
+ if (r < 0)
+ return r;
+
+ gcry_md_open(&md, algorithm, 0);
+ if (!md)
+ return -EIO;
+
+ gcry_md_write(md, wire_format, r);
+ gcry_md_write(md, nsec3->nsec3.salt, nsec3->nsec3.salt_size);
+
+ result = gcry_md_read(md, 0);
+ if (!result) {
+ r = -EIO;
+ goto finish;
+ }
+
+ for (k = 0; k < nsec3->nsec3.iterations; k++) {
+ uint8_t tmp[hash_size];
+ memcpy(tmp, result, hash_size);
+
+ gcry_md_reset(md);
+ gcry_md_write(md, tmp, hash_size);
+ gcry_md_write(md, nsec3->nsec3.salt, nsec3->nsec3.salt_size);
+
+ result = gcry_md_read(md, 0);
+ if (!result) {
+ r = -EIO;
+ goto finish;
+ }
+ }
+
+ memcpy(ret, result, hash_size);
+ r = (int) hash_size;
+
+finish:
+ gcry_md_close(md);
+ return r;
+}
+
+int dnssec_test_nsec(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result) {
+ DnsResourceRecord *rr;
+ int r;
+
+ assert(key);
+ assert(result);
+
+ /* Look for any NSEC/NSEC3 RRs that say something about the specified key. */
+
+ DNS_ANSWER_FOREACH(rr, answer) {
+
+ if (rr->key->class != key->class)
+ continue;
+
+ switch (rr->key->type) {
+
+ case DNS_TYPE_NSEC:
+
+ r = dns_name_equal(DNS_RESOURCE_KEY_NAME(rr->key), DNS_RESOURCE_KEY_NAME(key));
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ *result = bitmap_isset(rr->nsec.types, key->type) ? DNSSEC_NSEC_FOUND : DNSSEC_NSEC_NODATA;
+ return 0;
+ }
+
+ r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), DNS_RESOURCE_KEY_NAME(key), rr->nsec.next_domain_name);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ *result = DNSSEC_NSEC_NXDOMAIN;
+ return 0;
+ }
+ break;
+
+ case DNS_TYPE_NSEC3: {
+ _cleanup_free_ void *decoded = NULL;
+ size_t decoded_size;
+ char label[DNS_LABEL_MAX];
+ uint8_t hashed[DNSSEC_HASH_SIZE_MAX];
+ int label_length, c, q;
+ const char *p;
+ bool covered;
+
+ /* RFC 5155, Section 8.2 says we MUST ignore NSEC3 RRs with flags != 0 or 1 */
+ if (!IN_SET(rr->nsec3.flags, 0, 1))
+ continue;
+
+ p = DNS_RESOURCE_KEY_NAME(rr->key);
+ label_length = dns_label_unescape(&p, label, sizeof(label));
+ if (label_length < 0)
+ return label_length;
+ if (label_length == 0)
+ continue;
+
+ r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(key), p);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ r = unbase32hexmem(label, label_length, false, &decoded, &decoded_size);
+ if (r == -EINVAL)
+ continue;
+ if (r < 0)
+ return r;
+
+ if (decoded_size != rr->nsec3.next_hashed_name_size)
+ continue;
+
+ c = memcmp(decoded, rr->nsec3.next_hashed_name, decoded_size);
+ if (c == 0)
+ continue;
+
+ r = dnssec_nsec3_hash(rr, DNS_RESOURCE_KEY_NAME(key), hashed);
+ /* RFC 5155, Section 8.1 says we MUST ignore NSEC3 RRs with unknown algorithms */
+ if (r == -EOPNOTSUPP)
+ continue;
+ if (r < 0)
+ return r;
+ if ((size_t) r != decoded_size)
+ continue;
+
+ r = memcmp(decoded, hashed, decoded_size);
+ if (r == 0) {
+ *result = bitmap_isset(rr->nsec3.types, key->type) ? DNSSEC_NSEC_FOUND : DNSSEC_NSEC_NODATA;
+ return 0;
+ }
+
+ q = memcmp(hashed, rr->nsec3.next_hashed_name, decoded_size);
+
+ covered = c < 0 ?
+ r < 0 && q < 0 :
+ q < 0 || r < 0;
+
+ if (covered) {
+ *result = DNSSEC_NSEC_NXDOMAIN;
+ return 0;
+ }
+
+ break;
+ }
+
+ default:
+ break;
+ }
+ }
+
+ /* No approproate NSEC RR found, report this. */
+ *result = DNSSEC_NSEC_NO_RR;
+ return 0;
+}
+
static const char* const dnssec_mode_table[_DNSSEC_MODE_MAX] = {
[DNSSEC_NO] = "no",
[DNSSEC_TRUST] = "trust",
@@ -811,5 +993,6 @@ static const char* const dnssec_result_table[_DNSSEC_RESULT_MAX] = {
[DNSSEC_MISSING_KEY] = "missing-key",
[DNSSEC_UNSIGNED] = "unsigned",
[DNSSEC_FAILED_AUXILIARY] = "failed-auxiliary",
+ [DNSSEC_NSEC_MISMATCH] = "nsec-mismatch",
};
DEFINE_STRING_TABLE_LOOKUP(dnssec_result, DnssecResult);
diff --git a/src/resolve/resolved-dns-dnssec.h b/src/resolve/resolved-dns-dnssec.h
index f33abe3e11..442e301302 100644
--- a/src/resolve/resolved-dns-dnssec.h
+++ b/src/resolve/resolved-dns-dnssec.h
@@ -56,12 +56,16 @@ enum DnssecResult {
/* These two are added by the DnsTransaction logic */
DNSSEC_UNSIGNED,
DNSSEC_FAILED_AUXILIARY,
+ DNSSEC_NSEC_MISMATCH,
_DNSSEC_RESULT_MAX,
_DNSSEC_RESULT_INVALID = -1
};
#define DNSSEC_CANONICAL_HOSTNAME_MAX (DNS_HOSTNAME_MAX + 2)
+/* The longest digest we'll ever generate, of all digest algorithms we support */
+#define DNSSEC_HASH_SIZE_MAX (MAX(20, 32))
+
int dnssec_rrsig_match_dnskey(DnsResourceRecord *rrsig, DnsResourceRecord *dnskey);
int dnssec_key_match_rrsig(DnsResourceKey *key, DnsResourceRecord *rrsig);
@@ -75,6 +79,17 @@ uint16_t dnssec_keytag(DnsResourceRecord *dnskey);
int dnssec_canonicalize(const char *n, char *buffer, size_t buffer_max);
+int dnssec_nsec3_hash(DnsResourceRecord *nsec3, const char *name, void *ret);
+
+typedef enum DnssecNsecResult {
+ DNSSEC_NSEC_NO_RR, /* No suitable NSEC/NSEC3 RR found */
+ DNSSEC_NSEC_NXDOMAIN,
+ DNSSEC_NSEC_NODATA,
+ DNSSEC_NSEC_FOUND,
+} DnssecNsecResult;
+
+int dnssec_test_nsec(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result);
+
const char* dnssec_mode_to_string(DnssecMode m) _const_;
DnssecMode dnssec_mode_from_string(const char *s) _pure_;
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index 045627340b..f09788b0c6 100644
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -1472,8 +1472,57 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) {
/* Everything that's now in t->answer is known to be good, hence cacheable. */
t->n_answer_cacheable = (unsigned) -1; /* everything! */
- t->answer_authenticated = true;
- t->dnssec_result = DNSSEC_VALIDATED;
+ /* At this point the answer only contains validated
+ * RRsets. Now, let's see if it actually answers the question
+ * we asked. If so, great! If it doesn't, then see if
+ * NSEC/NSEC3 can prove this. */
+ r = dns_answer_match_key(t->answer, t->key);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ /* Yes, it answer the question, everything is authenticated. */
+ t->dnssec_result = DNSSEC_VALIDATED;
+ t->answer_rcode = DNS_RCODE_SUCCESS;
+ t->answer_authenticated = true;
+ } else if (r == 0) {
+ DnssecNsecResult nr;
+
+ /* Bummer! Let's check NSEC/NSEC3 */
+ r = dnssec_test_nsec(t->answer, t->key, &nr);
+ if (r < 0)
+ return r;
+
+ switch (nr) {
+
+ case DNSSEC_NSEC_NXDOMAIN:
+ /* NSEC proves the domain doesn't exist. Very good. */
+ t->dnssec_result = DNSSEC_VALIDATED;
+ t->answer_rcode = DNS_RCODE_NXDOMAIN;
+ t->answer_authenticated = true;
+ break;
+
+ case DNSSEC_NSEC_NODATA:
+ /* NSEC proves that there's no data here, very good. */
+ t->dnssec_result = DNSSEC_VALIDATED;
+ t->answer_rcode = DNS_RCODE_SUCCESS;
+ t->answer_authenticated = true;
+ break;
+
+ case DNSSEC_NSEC_NO_RR:
+ /* No NSEC data? Bummer! */
+ t->dnssec_result = DNSSEC_UNSIGNED;
+ break;
+
+ case DNSSEC_NSEC_FOUND:
+ /* NSEC says it needs to be there, but we couldn't find it? Bummer! */
+ t->dnssec_result = DNSSEC_NSEC_MISMATCH;
+ break;
+
+ default:
+ assert_not_reached("Unexpected NSEC result.");
+ }
+ }
+
return 1;
}
diff --git a/src/resolve/test-dnssec.c b/src/resolve/test-dnssec.c
index cbcb0fd94f..807eeb3d9a 100644
--- a/src/resolve/test-dnssec.c
+++ b/src/resolve/test-dnssec.c
@@ -27,6 +27,7 @@
#include "resolved-dns-dnssec.h"
#include "resolved-dns-rr.h"
#include "string-util.h"
+#include "hexdecoct.h"
static void test_dnssec_verify_rrset2(void) {
@@ -305,12 +306,46 @@ static void test_dnssec_canonicalize(void) {
test_dnssec_canonicalize_one("FOO..bar.", NULL, -EINVAL);
}
+static void test_dnssec_nsec3_hash(void) {
+ static const uint8_t salt[] = { 0xB0, 0x1D, 0xFA, 0xCE };
+ static const uint8_t next_hashed_name[] = { 0x84, 0x10, 0x26, 0x53, 0xc9, 0xfa, 0x4d, 0x85, 0x6c, 0x97, 0x82, 0xe2, 0x8f, 0xdf, 0x2d, 0x5e, 0x87, 0x69, 0xc4, 0x52 };
+ _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
+ _cleanup_free_ char *a = NULL, *b = NULL;
+ uint8_t h[DNSSEC_HASH_SIZE_MAX];
+ int k;
+
+ /* The NSEC3 RR for eurid.eu on 2015-12-14. */
+ rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_NSEC3, "PJ8S08RR45VIQDAQGE7EN3VHKNROTBMM.eurid.eu.");
+ assert_se(rr);
+
+ rr->nsec3.algorithm = DNSSEC_DIGEST_SHA1;
+ rr->nsec3.flags = 1;
+ rr->nsec3.iterations = 1;
+ rr->nsec3.salt = memdup(salt, sizeof(salt));
+ assert_se(rr->nsec3.salt);
+ rr->nsec3.salt_size = sizeof(salt);
+ rr->nsec3.next_hashed_name = memdup(next_hashed_name, sizeof(next_hashed_name));
+ assert_se(rr->nsec3.next_hashed_name);
+ rr->nsec3.next_hashed_name_size = sizeof(next_hashed_name);
+
+ assert_se(dns_resource_record_to_string(rr, &a) >= 0);
+ log_info("NSEC3: %s", a);
+
+ k = dnssec_nsec3_hash(rr, "eurid.eu", &h);
+ assert_se(k >= 0);
+
+ b = base32hexmem(h, k, false);
+ assert_se(b);
+ assert_se(strcasecmp(b, "PJ8S08RR45VIQDAQGE7EN3VHKNROTBMM") == 0);
+}
+
int main(int argc, char*argv[]) {
test_dnssec_canonicalize();
test_dnssec_verify_dns_key();
test_dnssec_verify_rrset();
test_dnssec_verify_rrset2();
+ test_dnssec_nsec3_hash();
return 0;
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-03 06:51:21 +0000