*
* TODO:
*
- * - Make trust anchor store read additional DS+DNSKEY data from disk
* - wildcard zones compatibility (NSEC/NSEC3 wildcard check is missing)
* - multi-label zone compatibility
* - cname/dname compatibility
- * - per-interface DNSSEC setting
- * - fix TTL for cache entries to match RRSIG TTL
- * - retry on failed validation?
- * - DSA support
- * - EC support?
+ * - nxdomain on qname
+ * - bus calls to override DNSEC setting per interface
+ * - log all DNSSEC downgrades
+ * - enable by default
*
+ * - RFC 4035, Section 5.3.4 (When receiving a positive wildcard reply, use NSEC to ensure it actually really applies)
+ * - RFC 6840, Section 4.1 (ensure we don't get fed a glue NSEC from the parent zone)
+ * - RFC 6840, Section 4.3 (check for CNAME on NSEC too)
* */
#define VERIFY_RRS_MAX 256
/* Permit a maximum clock skew of 1h 10min. This should be enough to deal with DST confusion */
#define SKEW_MAX (1*USEC_PER_HOUR + 10*USEC_PER_MINUTE)
+/* Maximum number of NSEC3 iterations we'll do. RFC5155 says 2500 shall be the maximum useful value */
+#define NSEC3_ITERATIONS_MAX 2500
+
/*
* The DNSSEC Chain of trust:
*
gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
}
-static bool dnssec_algorithm_supported(int algorithm) {
- return IN_SET(algorithm,
- DNSSEC_ALGORITHM_RSASHA1,
- DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1,
- DNSSEC_ALGORITHM_RSASHA256,
- DNSSEC_ALGORITHM_RSASHA512);
-}
-
-uint16_t dnssec_keytag(DnsResourceRecord *dnskey) {
+uint16_t dnssec_keytag(DnsResourceRecord *dnskey, bool mask_revoke) {
const uint8_t *p;
- uint32_t sum;
+ uint32_t sum, f;
size_t i;
/* The algorithm from RFC 4034, Appendix B. */
assert(dnskey);
assert(dnskey->key->type == DNS_TYPE_DNSKEY);
- sum = (uint32_t) dnskey->dnskey.flags +
- ((((uint32_t) dnskey->dnskey.protocol) << 8) + (uint32_t) dnskey->dnskey.algorithm);
+ f = (uint32_t) dnskey->dnskey.flags;
+
+ if (mask_revoke)
+ f &= ~DNSKEY_FLAG_REVOKE;
+
+ sum = f + ((((uint32_t) dnskey->dnskey.protocol) << 8) + (uint32_t) dnskey->dnskey.algorithm);
p = dnskey->dnskey.key;
assert(*y);
assert((*y)->wire_format);
- m = MIN((*x)->wire_format_size, (*y)->wire_format_size);
+ m = MIN(DNS_RESOURCE_RECORD_RDATA_SIZE(*x), DNS_RESOURCE_RECORD_RDATA_SIZE(*y));
- r = memcmp((*x)->wire_format, (*y)->wire_format, m);
+ r = memcmp(DNS_RESOURCE_RECORD_RDATA(*x), DNS_RESOURCE_RECORD_RDATA(*y), m);
if (r != 0)
return r;
- if ((*x)->wire_format_size < (*y)->wire_format_size)
+ if (DNS_RESOURCE_RECORD_RDATA_SIZE(*x) < DNS_RESOURCE_RECORD_RDATA_SIZE(*y))
return -1;
- else if ((*x)->wire_format_size > (*y)->wire_format_size)
+ else if (DNS_RESOURCE_RECORD_RDATA_SIZE(*x) > DNS_RESOURCE_RECORD_RDATA_SIZE(*y))
return 1;
return 0;
}
-static int dnssec_rsa_verify(
+static int dnssec_rsa_verify_raw(
const char *hash_algorithm,
const void *signature, size_t signature_size,
const void *data, size_t data_size,
return r;
}
+static int dnssec_rsa_verify(
+ const char *hash_algorithm,
+ const void *hash, size_t hash_size,
+ DnsResourceRecord *rrsig,
+ DnsResourceRecord *dnskey) {
+
+ size_t exponent_size, modulus_size;
+ void *exponent, *modulus;
+
+ assert(hash_algorithm);
+ assert(hash);
+ assert(hash_size > 0);
+ assert(rrsig);
+ assert(dnskey);
+
+ if (*(uint8_t*) dnskey->dnskey.key == 0) {
+ /* exponent is > 255 bytes long */
+
+ exponent = (uint8_t*) dnskey->dnskey.key + 3;
+ exponent_size =
+ ((size_t) (((uint8_t*) dnskey->dnskey.key)[1]) << 8) |
+ ((size_t) ((uint8_t*) dnskey->dnskey.key)[2]);
+
+ if (exponent_size < 256)
+ return -EINVAL;
+
+ if (3 + exponent_size >= dnskey->dnskey.key_size)
+ return -EINVAL;
+
+ modulus = (uint8_t*) dnskey->dnskey.key + 3 + exponent_size;
+ modulus_size = dnskey->dnskey.key_size - 3 - exponent_size;
+
+ } else {
+ /* exponent is <= 255 bytes long */
+
+ exponent = (uint8_t*) dnskey->dnskey.key + 1;
+ exponent_size = (size_t) ((uint8_t*) dnskey->dnskey.key)[0];
+
+ if (exponent_size <= 0)
+ return -EINVAL;
+
+ if (1 + exponent_size >= dnskey->dnskey.key_size)
+ return -EINVAL;
+
+ modulus = (uint8_t*) dnskey->dnskey.key + 1 + exponent_size;
+ modulus_size = dnskey->dnskey.key_size - 1 - exponent_size;
+ }
+
+ return dnssec_rsa_verify_raw(
+ hash_algorithm,
+ rrsig->rrsig.signature, rrsig->rrsig.signature_size,
+ hash, hash_size,
+ exponent, exponent_size,
+ modulus, modulus_size);
+}
+
+static int dnssec_ecdsa_verify_raw(
+ const char *hash_algorithm,
+ const char *curve,
+ const void *signature_r, size_t signature_r_size,
+ const void *signature_s, size_t signature_s_size,
+ const void *data, size_t data_size,
+ const void *key, size_t key_size) {
+
+ gcry_sexp_t public_key_sexp = NULL, data_sexp = NULL, signature_sexp = NULL;
+ gcry_mpi_t q = NULL, r = NULL, s = NULL;
+ gcry_error_t ge;
+ int k;
+
+ assert(hash_algorithm);
+
+ ge = gcry_mpi_scan(&r, GCRYMPI_FMT_USG, signature_r, signature_r_size, NULL);
+ if (ge != 0) {
+ k = -EIO;
+ goto finish;
+ }
+
+ ge = gcry_mpi_scan(&s, GCRYMPI_FMT_USG, signature_s, signature_s_size, NULL);
+ if (ge != 0) {
+ k = -EIO;
+ goto finish;
+ }
+
+ ge = gcry_mpi_scan(&q, GCRYMPI_FMT_USG, key, key_size, NULL);
+ if (ge != 0) {
+ k = -EIO;
+ goto finish;
+ }
+
+ ge = gcry_sexp_build(&signature_sexp,
+ NULL,
+ "(sig-val (ecdsa (r %m) (s %m)))",
+ r,
+ s);
+ if (ge != 0) {
+ k = -EIO;
+ goto finish;
+ }
+
+ ge = gcry_sexp_build(&data_sexp,
+ NULL,
+ "(data (flags rfc6979) (hash %s %b))",
+ hash_algorithm,
+ (int) data_size,
+ data);
+ if (ge != 0) {
+ k = -EIO;
+ goto finish;
+ }
+
+ ge = gcry_sexp_build(&public_key_sexp,
+ NULL,
+ "(public-key (ecc (curve %s) (q %m)))",
+ curve,
+ q);
+ if (ge != 0) {
+ k = -EIO;
+ goto finish;
+ }
+
+ ge = gcry_pk_verify(signature_sexp, data_sexp, public_key_sexp);
+ if (gpg_err_code(ge) == GPG_ERR_BAD_SIGNATURE)
+ k = 0;
+ else if (ge != 0) {
+ log_debug("ECDSA signature check failed: %s", gpg_strerror(ge));
+ k = -EIO;
+ } else
+ k = 1;
+finish:
+ if (r)
+ gcry_mpi_release(r);
+ if (s)
+ gcry_mpi_release(s);
+ if (q)
+ gcry_mpi_release(q);
+
+ if (public_key_sexp)
+ gcry_sexp_release(public_key_sexp);
+ if (signature_sexp)
+ gcry_sexp_release(signature_sexp);
+ if (data_sexp)
+ gcry_sexp_release(data_sexp);
+
+ return k;
+}
+
+static int dnssec_ecdsa_verify(
+ const char *hash_algorithm,
+ int algorithm,
+ const void *hash, size_t hash_size,
+ DnsResourceRecord *rrsig,
+ DnsResourceRecord *dnskey) {
+
+ const char *curve;
+ size_t key_size;
+ uint8_t *q;
+
+ assert(hash);
+ assert(hash_size);
+ assert(rrsig);
+ assert(dnskey);
+
+ if (algorithm == DNSSEC_ALGORITHM_ECDSAP256SHA256) {
+ key_size = 32;
+ curve = "NIST P-256";
+ } else if (algorithm == DNSSEC_ALGORITHM_ECDSAP384SHA384) {
+ key_size = 48;
+ curve = "NIST P-384";
+ } else
+ return -EOPNOTSUPP;
+
+ if (dnskey->dnskey.key_size != key_size * 2)
+ return -EINVAL;
+
+ if (rrsig->rrsig.signature_size != key_size * 2)
+ return -EINVAL;
+
+ q = alloca(key_size*2 + 1);
+ q[0] = 0x04; /* Prepend 0x04 to indicate an uncompressed key */
+ memcpy(q+1, dnskey->dnskey.key, key_size*2);
+
+ return dnssec_ecdsa_verify_raw(
+ hash_algorithm,
+ curve,
+ rrsig->rrsig.signature, key_size,
+ (uint8_t*) rrsig->rrsig.signature + key_size, key_size,
+ hash, hash_size,
+ q, key_size*2+1);
+}
+
static void md_add_uint8(gcry_md_hd_t md, uint8_t v) {
gcry_md_write(md, &v, sizeof(v));
}
expiration = rrsig->rrsig.expiration * USEC_PER_SEC;
inception = rrsig->rrsig.inception * USEC_PER_SEC;
+ /* Consider inverted validity intervals as expired */
if (inception > expiration)
- return -EKEYREJECTED;
+ return true;
/* Permit a certain amount of clock skew of 10% of the valid
* time range. This takes inspiration from unbound's
return realtime < inception || realtime > expiration;
}
+static int algorithm_to_gcrypt_md(uint8_t algorithm) {
+
+ /* Translates a DNSSEC signature algorithm into a gcrypt
+ * digest identifier.
+ *
+ * Note that we implement all algorithms listed as "Must
+ * implement" and "Recommended to Implement" in RFC6944. We
+ * don't implement any algorithms that are listed as
+ * "Optional" or "Must Not Implement". Specifically, we do not
+ * implement RSAMD5, DSASHA1, DH, DSA-NSEC3-SHA1, and
+ * GOST-ECC. */
+
+ switch (algorithm) {
+
+ case DNSSEC_ALGORITHM_RSASHA1:
+ case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1:
+ return GCRY_MD_SHA1;
+
+ case DNSSEC_ALGORITHM_RSASHA256:
+ case DNSSEC_ALGORITHM_ECDSAP256SHA256:
+ return GCRY_MD_SHA256;
+
+ case DNSSEC_ALGORITHM_ECDSAP384SHA384:
+ return GCRY_MD_SHA384;
+
+ case DNSSEC_ALGORITHM_RSASHA512:
+ return GCRY_MD_SHA512;
+
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
int dnssec_verify_rrset(
DnsAnswer *a,
- DnsResourceKey *key,
+ const DnsResourceKey *key,
DnsResourceRecord *rrsig,
DnsResourceRecord *dnskey,
usec_t realtime,
DnssecResult *result) {
uint8_t wire_format_name[DNS_WIRE_FOMAT_HOSTNAME_MAX];
- size_t exponent_size, modulus_size, hash_size;
- void *exponent, *modulus, *hash;
+ size_t hash_size;
+ void *hash;
DnsResourceRecord **list, *rr;
gcry_md_hd_t md = NULL;
+ int r, md_algorithm;
size_t k, n = 0;
- int r;
+ bool wildcard;
+ const char *source;
assert(key);
assert(rrsig);
* using the signature "rrsig" and the key "dnskey". It's
* assumed the RRSIG and DNSKEY match. */
- if (!dnssec_algorithm_supported(rrsig->rrsig.algorithm)) {
+ md_algorithm = algorithm_to_gcrypt_md(rrsig->rrsig.algorithm);
+ if (md_algorithm == -EOPNOTSUPP) {
*result = DNSSEC_UNSUPPORTED_ALGORITHM;
return 0;
}
-
- if (a->n_rrs > VERIFY_RRS_MAX)
- return -E2BIG;
+ if (md_algorithm < 0)
+ return md_algorithm;
r = dnssec_rrsig_expired(rrsig, realtime);
if (r < 0)
return 0;
}
+ /* Determine the "Source of Synthesis" and whether this is a wildcard RRSIG */
+ r = dns_name_suffix(DNS_RESOURCE_KEY_NAME(key), rrsig->rrsig.labels, &source);
+ if (r < 0)
+ return r;
+ if (r > 0 && !dns_type_may_wildcard(rrsig->rrsig.type_covered)) {
+ /* We refuse to validate NSEC3 or SOA RRs that are synthesized from wildcards */
+ *result = DNSSEC_INVALID;
+ return 0;
+ }
+ if (r == 1) {
+ /* If we stripped a single label, then let's see if that maybe was "*". If so, we are not really
+ * synthesized from a wildcard, we are the wildcard itself. Treat that like a normal name. */
+ r = dns_name_startswith(DNS_RESOURCE_KEY_NAME(key), "*");
+ if (r < 0)
+ return r;
+ if (r > 0)
+ source = DNS_RESOURCE_KEY_NAME(key);
+
+ wildcard = r == 0;
+ } else
+ wildcard = r > 0;
+
/* Collect all relevant RRs in a single array, so that we can look at the RRset */
- list = newa(DnsResourceRecord *, a->n_rrs);
+ list = newa(DnsResourceRecord *, dns_answer_size(a));
DNS_ANSWER_FOREACH(rr, a) {
r = dns_resource_key_equal(key, rr->key);
return r;
list[n++] = rr;
+
+ if (n > VERIFY_RRS_MAX)
+ return -E2BIG;
}
if (n <= 0)
/* Bring the RRs into canonical order */
qsort_safe(list, n, sizeof(DnsResourceRecord*), rr_compare);
- initialize_libgcrypt();
-
/* OK, the RRs are now in canonical order. Let's calculate the digest */
- switch (rrsig->rrsig.algorithm) {
-
- case DNSSEC_ALGORITHM_RSASHA1:
- case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1:
- gcry_md_open(&md, GCRY_MD_SHA1, 0);
- hash_size = 20;
- break;
-
- case DNSSEC_ALGORITHM_RSASHA256:
- gcry_md_open(&md, GCRY_MD_SHA256, 0);
- hash_size = 32;
- break;
-
- case DNSSEC_ALGORITHM_RSASHA512:
- gcry_md_open(&md, GCRY_MD_SHA512, 0);
- hash_size = 64;
- break;
+ initialize_libgcrypt();
- default:
- assert_not_reached("Unknown digest");
- }
+ hash_size = gcry_md_get_algo_dlen(md_algorithm);
+ assert(hash_size > 0);
+ gcry_md_open(&md, md_algorithm, 0);
if (!md)
return -EIO;
goto finish;
gcry_md_write(md, wire_format_name, r);
+ /* Convert the source of synthesis into wire format */
+ r = dns_name_to_wire_format(source, wire_format_name, sizeof(wire_format_name), true);
+ if (r < 0)
+ goto finish;
+
for (k = 0; k < n; k++) {
- const char *suffix;
size_t l;
+
rr = list[k];
- r = dns_name_suffix(DNS_RESOURCE_KEY_NAME(rr->key), rrsig->rrsig.labels, &suffix);
- if (r < 0)
- goto finish;
- if (r > 0) /* This is a wildcard! */
+ /* Hash the source of synthesis. If this is a wildcard, then prefix it with the *. label */
+ if (wildcard)
gcry_md_write(md, (uint8_t[]) { 1, '*'}, 2);
-
- r = dns_name_to_wire_format(suffix, wire_format_name, sizeof(wire_format_name), true);
- if (r < 0)
- goto finish;
gcry_md_write(md, wire_format_name, r);
md_add_uint16(md, rr->key->type);
md_add_uint16(md, rr->key->class);
md_add_uint32(md, rrsig->rrsig.original_ttl);
- assert(rr->wire_format_rdata_offset <= rr->wire_format_size);
- l = rr->wire_format_size - rr->wire_format_rdata_offset;
+ l = DNS_RESOURCE_RECORD_RDATA_SIZE(rr);
assert(l <= 0xFFFF);
md_add_uint16(md, (uint16_t) l);
- gcry_md_write(md, (uint8_t*) rr->wire_format + rr->wire_format_rdata_offset, l);
+ gcry_md_write(md, DNS_RESOURCE_RECORD_RDATA(rr), l);
}
hash = gcry_md_read(md, 0);
goto finish;
}
- if (*(uint8_t*) dnskey->dnskey.key == 0) {
- /* exponent is > 255 bytes long */
-
- exponent = (uint8_t*) dnskey->dnskey.key + 3;
- exponent_size =
- ((size_t) (((uint8_t*) dnskey->dnskey.key)[0]) << 8) |
- ((size_t) ((uint8_t*) dnskey->dnskey.key)[1]);
-
- if (exponent_size < 256) {
- r = -EINVAL;
- goto finish;
- }
-
- if (3 + exponent_size >= dnskey->dnskey.key_size) {
- r = -EINVAL;
- goto finish;
- }
-
- modulus = (uint8_t*) dnskey->dnskey.key + 3 + exponent_size;
- modulus_size = dnskey->dnskey.key_size - 3 - exponent_size;
-
- } else {
- /* exponent is <= 255 bytes long */
-
- exponent = (uint8_t*) dnskey->dnskey.key + 1;
- exponent_size = (size_t) ((uint8_t*) dnskey->dnskey.key)[0];
-
- if (exponent_size <= 0) {
- r = -EINVAL;
- goto finish;
- }
+ switch (rrsig->rrsig.algorithm) {
- if (1 + exponent_size >= dnskey->dnskey.key_size) {
- r = -EINVAL;
- goto finish;
- }
+ case DNSSEC_ALGORITHM_RSASHA1:
+ case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1:
+ case DNSSEC_ALGORITHM_RSASHA256:
+ case DNSSEC_ALGORITHM_RSASHA512:
+ r = dnssec_rsa_verify(
+ gcry_md_algo_name(md_algorithm),
+ hash, hash_size,
+ rrsig,
+ dnskey);
+ break;
- modulus = (uint8_t*) dnskey->dnskey.key + 1 + exponent_size;
- modulus_size = dnskey->dnskey.key_size - 1 - exponent_size;
+ case DNSSEC_ALGORITHM_ECDSAP256SHA256:
+ case DNSSEC_ALGORITHM_ECDSAP384SHA384:
+ r = dnssec_ecdsa_verify(
+ gcry_md_algo_name(md_algorithm),
+ rrsig->rrsig.algorithm,
+ hash, hash_size,
+ rrsig,
+ dnskey);
+ break;
}
- r = dnssec_rsa_verify(
- gcry_md_algo_name(gcry_md_get_algo(md)),
- rrsig->rrsig.signature, rrsig->rrsig.signature_size,
- hash, hash_size,
- exponent, exponent_size,
- modulus, modulus_size);
if (r < 0)
goto finish;
- *result = r ? DNSSEC_VALIDATED : DNSSEC_INVALID;
+ if (!r)
+ *result = DNSSEC_INVALID;
+ else if (wildcard)
+ *result = DNSSEC_VALIDATED_WILDCARD;
+ else
+ *result = DNSSEC_VALIDATED;
r = 0;
finish:
return r;
}
-int dnssec_rrsig_match_dnskey(DnsResourceRecord *rrsig, DnsResourceRecord *dnskey) {
+int dnssec_rrsig_match_dnskey(DnsResourceRecord *rrsig, DnsResourceRecord *dnskey, bool revoked_ok) {
assert(rrsig);
assert(dnskey);
return 0;
if ((dnskey->dnskey.flags & DNSKEY_FLAG_ZONE_KEY) == 0)
return 0;
+ if (!revoked_ok && (dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE))
+ return 0;
if (dnskey->dnskey.protocol != 3)
return 0;
if (dnskey->dnskey.algorithm != rrsig->rrsig.algorithm)
return 0;
- if (dnssec_keytag(dnskey) != rrsig->rrsig.key_tag)
+ if (dnssec_keytag(dnskey, false) != rrsig->rrsig.key_tag)
return 0;
return dns_name_equal(DNS_RESOURCE_KEY_NAME(dnskey->key), rrsig->rrsig.signer);
return dns_name_equal(DNS_RESOURCE_KEY_NAME(rrsig->key), DNS_RESOURCE_KEY_NAME(key));
}
+static int dnssec_fix_rrset_ttl(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord *rrsig, usec_t realtime) {
+ DnsResourceRecord *rr;
+ int r;
+
+ assert(key);
+ assert(rrsig);
+
+ DNS_ANSWER_FOREACH(rr, a) {
+ r = dns_resource_key_equal(key, rr->key);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ /* Pick the TTL as the minimum of the RR's TTL, the
+ * RR's original TTL according to the RRSIG and the
+ * RRSIG's own TTL, see RFC 4035, Section 5.3.3 */
+ rr->ttl = MIN3(rr->ttl, rrsig->rrsig.original_ttl, rrsig->ttl);
+ rr->expiry = rrsig->rrsig.expiration * USEC_PER_SEC;
+ }
+
+ return 0;
+}
+
int dnssec_verify_rrset_search(
DnsAnswer *a,
- DnsResourceKey *key,
+ const DnsResourceKey *key,
DnsAnswer *validated_dnskeys,
usec_t realtime,
- DnssecResult *result) {
+ DnssecResult *result,
+ DnsResourceRecord **ret_rrsig) {
bool found_rrsig = false, found_invalid = false, found_expired_rrsig = false, found_unsupported_algorithm = false;
DnsResourceRecord *rrsig;
continue;
/* Is this a DNSKEY RR that matches they key of our RRSIG? */
- r = dnssec_rrsig_match_dnskey(rrsig, dnskey);
+ r = dnssec_rrsig_match_dnskey(rrsig, dnskey, false);
if (r < 0)
return r;
if (r == 0)
switch (one_result) {
case DNSSEC_VALIDATED:
+ case DNSSEC_VALIDATED_WILDCARD:
/* Yay, the RR has been validated,
- * return immediately. */
- *result = DNSSEC_VALIDATED;
+ * return immediately, but fix up the expiry */
+ r = dnssec_fix_rrset_ttl(a, key, rrsig, realtime);
+ if (r < 0)
+ return r;
+
+ if (ret_rrsig)
+ *ret_rrsig = rrsig;
+
+ *result = one_result;
return 0;
case DNSSEC_INVALID:
else
*result = DNSSEC_NO_SIGNATURE;
+ if (ret_rrsig)
+ *ret_rrsig = NULL;
+
return 0;
}
return -ENOBUFS;
for (;;) {
- size_t i;
-
r = dns_label_unescape(&n, buffer, buffer_max);
if (r < 0)
return r;
if (memchr(buffer, '.', r))
return -EINVAL;
- for (i = 0; i < (size_t) r; i ++) {
- if (buffer[i] >= 'A' && buffer[i] <= 'Z')
- buffer[i] = buffer[i] - 'A' + 'a';
- }
-
+ ascii_strlower_n(buffer, (size_t) r);
buffer[r] = '.';
buffer += r + 1;
return (int) c;
}
-static int digest_to_gcrypt(uint8_t algorithm) {
+static int digest_to_gcrypt_md(uint8_t algorithm) {
- /* Translates a DNSSEC digest algorithm into a gcrypt digest iedntifier */
+ /* Translates a DNSSEC digest algorithm into a gcrypt digest identifier */
switch (algorithm) {
case DNSSEC_DIGEST_SHA256:
return GCRY_MD_SHA256;
+ case DNSSEC_DIGEST_SHA384:
+ return GCRY_MD_SHA384;
+
default:
return -EOPNOTSUPP;
}
}
-int dnssec_verify_dnskey(DnsResourceRecord *dnskey, DnsResourceRecord *ds) {
+int dnssec_verify_dnskey(DnsResourceRecord *dnskey, DnsResourceRecord *ds, bool mask_revoke) {
char owner_name[DNSSEC_CANONICAL_HOSTNAME_MAX];
gcry_md_hd_t md = NULL;
size_t hash_size;
- int algorithm;
+ int md_algorithm, r;
void *result;
- int r;
assert(dnskey);
assert(ds);
return -EINVAL;
if ((dnskey->dnskey.flags & DNSKEY_FLAG_ZONE_KEY) == 0)
return -EKEYREJECTED;
+ if (!mask_revoke && (dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE))
+ return -EKEYREJECTED;
if (dnskey->dnskey.protocol != 3)
return -EKEYREJECTED;
if (dnskey->dnskey.algorithm != ds->ds.algorithm)
return 0;
- if (dnssec_keytag(dnskey) != ds->ds.key_tag)
+ if (dnssec_keytag(dnskey, mask_revoke) != ds->ds.key_tag)
return 0;
initialize_libgcrypt();
- algorithm = digest_to_gcrypt(ds->ds.digest_type);
- if (algorithm < 0)
- return algorithm;
+ md_algorithm = digest_to_gcrypt_md(ds->ds.digest_type);
+ if (md_algorithm < 0)
+ return md_algorithm;
- hash_size = gcry_md_get_algo_dlen(algorithm);
+ hash_size = gcry_md_get_algo_dlen(md_algorithm);
assert(hash_size > 0);
if (ds->ds.digest_size != hash_size)
if (r < 0)
return r;
- gcry_md_open(&md, algorithm, 0);
+ gcry_md_open(&md, md_algorithm, 0);
if (!md)
return -EIO;
gcry_md_write(md, owner_name, r);
- md_add_uint16(md, dnskey->dnskey.flags);
+ if (mask_revoke)
+ md_add_uint16(md, dnskey->dnskey.flags & ~DNSKEY_FLAG_REVOKE);
+ else
+ md_add_uint16(md, dnskey->dnskey.flags);
md_add_uint8(md, dnskey->dnskey.protocol);
md_add_uint8(md, dnskey->dnskey.algorithm);
gcry_md_write(md, dnskey->dnskey.key, dnskey->dnskey.key_size);
if (r == 0)
continue;
- r = dnssec_verify_dnskey(dnskey, ds);
+ r = dnssec_verify_dnskey(dnskey, ds, false);
+ if (r == -EKEYREJECTED)
+ return 0; /* The DNSKEY is revoked or otherwise invalid, we won't bless it */
if (r < 0)
return r;
if (r > 0)
return 0;
}
+static int nsec3_hash_to_gcrypt_md(uint8_t algorithm) {
+
+ /* Translates a DNSSEC NSEC3 hash algorithm into a gcrypt digest identifier */
+
+ switch (algorithm) {
+
+ case NSEC3_ALGORITHM_SHA1:
+ return GCRY_MD_SHA1;
+
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
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;
if (nsec3->key->type != DNS_TYPE_NSEC3)
return -EINVAL;
- algorithm = digest_to_gcrypt(nsec3->nsec3.algorithm);
+ if (nsec3->nsec3.iterations > NSEC3_ITERATIONS_MAX) {
+ log_debug("Ignoring NSEC3 RR %s with excessive number of iterations.", dns_resource_record_to_string(nsec3));
+ return -EOPNOTSUPP;
+ }
+
+ algorithm = nsec3_hash_to_gcrypt_md(nsec3->nsec3.algorithm);
if (algorithm < 0)
return algorithm;
return r;
}
-static int nsec3_is_good(DnsResourceRecord *rr, DnsAnswerFlags flags, DnsResourceRecord *nsec3) {
+static int nsec3_is_good(DnsResourceRecord *rr, DnsResourceRecord *nsec3) {
const char *a, *b;
int r;
if (!IN_SET(rr->nsec3.flags, 0, 1))
return 0;
+ /* Ignore NSEC3 RRs whose algorithm we don't know */
+ if (nsec3_hash_to_gcrypt_md(rr->nsec3.algorithm) < 0)
+ return 0;
+ /* Ignore NSEC3 RRs with an excessive number of required iterations */
+ if (rr->nsec3.iterations > NSEC3_ITERATIONS_MAX)
+ return 0;
+
if (!nsec3)
return 1;
return dns_name_equal(a, b);
}
-static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated) {
- _cleanup_free_ char *next_closer_domain = NULL, *l = NULL;
+static int nsec3_hashed_domain_format(const uint8_t *hashed, size_t hashed_size, const char *zone, char **ret) {
+ _cleanup_free_ char *l = NULL;
+ char *j;
+
+ assert(hashed);
+ assert(hashed_size > 0);
+ assert(zone);
+ assert(ret);
+
+ l = base32hexmem(hashed, hashed_size, false);
+ if (!l)
+ return -ENOMEM;
+
+ j = strjoin(l, ".", zone, NULL);
+ if (!j)
+ return -ENOMEM;
+
+ *ret = j;
+ return (int) hashed_size;
+}
+
+static int nsec3_hashed_domain_make(DnsResourceRecord *nsec3, const char *domain, const char *zone, char **ret) {
uint8_t hashed[DNSSEC_HASH_SIZE_MAX];
- const char *suffix, *p, *pp = NULL;
- DnsResourceRecord *rr, *suffix_rr;
+ int hashed_size;
+
+ assert(nsec3);
+ assert(domain);
+ assert(zone);
+ assert(ret);
+
+ hashed_size = dnssec_nsec3_hash(nsec3, domain, hashed);
+ if (hashed_size < 0)
+ return hashed_size;
+
+ return nsec3_hashed_domain_format(hashed, (size_t) hashed_size, zone, ret);
+}
+
+/* See RFC 5155, Section 8
+ * First try to find a NSEC3 record that matches our query precisely, if that fails, find the closest
+ * enclosure. Secondly, find a proof that there is no closer enclosure and either a proof that there
+ * is no wildcard domain as a direct descendant of the closest enclosure, or find an NSEC3 record that
+ * matches the wildcard domain.
+ *
+ * Based on this we can prove either the existence of the record in @key, or NXDOMAIN or NODATA, or
+ * that there is no proof either way. The latter is the case if a the proof of non-existence of a given
+ * name uses an NSEC3 record with the opt-out bit set. Lastly, if we are given insufficient NSEC3 records
+ * to conclude anything we indicate this by returning NO_RR. */
+static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl) {
+ _cleanup_free_ char *next_closer_domain = NULL, *wildcard_domain = NULL;
+ const char *zone, *p, *pp = NULL, *wildcard;
+ DnsResourceRecord *rr, *enclosure_rr, *zone_rr, *wildcard_rr = NULL;
DnsAnswerFlags flags;
int hashed_size, r;
- bool a;
+ bool a, no_closer = false, no_wildcard = false, optout = false;
assert(key);
assert(result);
- assert(authenticated);
- /* First step, look for the longest common suffix we find with any NSEC3 RR in the response. */
- suffix = DNS_RESOURCE_KEY_NAME(key);
+ /* First step, find the zone name and the NSEC3 parameters of the zone.
+ * it is sufficient to look for the longest common suffix we find with
+ * any NSEC3 RR in the response. Any NSEC3 record will do as all NSEC3
+ * records from a given zone in a response must use the same
+ * parameters. */
+ zone = DNS_RESOURCE_KEY_NAME(key);
for (;;) {
- DNS_ANSWER_FOREACH_FLAGS(suffix_rr, flags, answer) {
- r = nsec3_is_good(suffix_rr, flags, NULL);
+ DNS_ANSWER_FOREACH_FLAGS(zone_rr, flags, answer) {
+ r = nsec3_is_good(zone_rr, NULL);
if (r < 0)
return r;
if (r == 0)
continue;
- r = dns_name_equal_skip(DNS_RESOURCE_KEY_NAME(suffix_rr->key), 1, suffix);
+ r = dns_name_equal_skip(DNS_RESOURCE_KEY_NAME(zone_rr->key), 1, zone);
if (r < 0)
return r;
if (r > 0)
- goto found_suffix;
+ goto found_zone;
}
/* Strip one label from the front */
- r = dns_name_parent(&suffix);
+ r = dns_name_parent(&zone);
if (r < 0)
return r;
if (r == 0)
*result = DNSSEC_NSEC_NO_RR;
return 0;
-found_suffix:
+found_zone:
/* Second step, find the closest encloser NSEC3 RR in 'answer' that matches 'key' */
p = DNS_RESOURCE_KEY_NAME(key);
for (;;) {
- _cleanup_free_ char *hashed_domain = NULL, *label = NULL;
+ _cleanup_free_ char *hashed_domain = NULL;
- hashed_size = dnssec_nsec3_hash(suffix_rr, p, hashed);
+ hashed_size = nsec3_hashed_domain_make(zone_rr, p, zone, &hashed_domain);
if (hashed_size == -EOPNOTSUPP) {
*result = DNSSEC_NSEC_UNSUPPORTED_ALGORITHM;
return 0;
if (hashed_size < 0)
return hashed_size;
- label = base32hexmem(hashed, hashed_size, false);
- if (!label)
- return -ENOMEM;
-
- hashed_domain = strjoin(label, ".", suffix, NULL);
- if (!hashed_domain)
- return -ENOMEM;
-
- DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) {
+ DNS_ANSWER_FOREACH_FLAGS(enclosure_rr, flags, answer) {
- r = nsec3_is_good(rr, flags, suffix_rr);
+ r = nsec3_is_good(enclosure_rr, zone_rr);
if (r < 0)
return r;
if (r == 0)
continue;
- if (rr->nsec3.next_hashed_name_size != (size_t) hashed_size)
+ if (enclosure_rr->nsec3.next_hashed_name_size != (size_t) hashed_size)
continue;
- r = dns_name_equal(DNS_RESOURCE_KEY_NAME(rr->key), hashed_domain);
+ r = dns_name_equal(DNS_RESOURCE_KEY_NAME(enclosure_rr->key), hashed_domain);
if (r < 0)
return r;
if (r > 0) {
/* We found a closest encloser in 'p'; next closer is 'pp' */
/* Ensure this is not a DNAME domain, see RFC5155, section 8.3. */
- if (bitmap_isset(rr->nsec3.types, DNS_TYPE_DNAME))
+ if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_DNAME))
return -EBADMSG;
/* Ensure that this data is from the delegated domain
* (i.e. originates from the "lower" DNS server), and isn't
* just glue records (i.e. doesn't originate from the "upper"
* DNS server). */
- if (bitmap_isset(rr->nsec3.types, DNS_TYPE_NS) &&
- !bitmap_isset(rr->nsec3.types, DNS_TYPE_SOA))
+ if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_NS) &&
+ !bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_SOA))
return -EBADMSG;
if (!pp) {
/* No next closer NSEC3 RR. That means there's a direct NSEC3 RR for our key. */
- *result = bitmap_isset(rr->nsec3.types, key->type) ? DNSSEC_NSEC_FOUND : DNSSEC_NSEC_NODATA;
- *authenticated = a;
+ if (bitmap_isset(enclosure_rr->nsec3.types, key->type))
+ *result = DNSSEC_NSEC_FOUND;
+ else if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_CNAME))
+ *result = DNSSEC_NSEC_CNAME;
+ else
+ *result = DNSSEC_NSEC_NODATA;
+
+ if (authenticated)
+ *authenticated = a;
+ if (ttl)
+ *ttl = enclosure_rr->ttl;
+
return 0;
}
- r = dnssec_nsec3_hash(rr, pp, hashed);
+ /* Prove that there is no next closer and whether or not there is a wildcard domain. */
+
+ wildcard = strjoina("*.", p);
+ r = nsec3_hashed_domain_make(enclosure_rr, wildcard, zone, &wildcard_domain);
if (r < 0)
return r;
if (r != hashed_size)
return -EBADMSG;
- l = base32hexmem(hashed, hashed_size, false);
- if (!l)
- return -ENOMEM;
-
- next_closer_domain = strjoin(l, ".", p, NULL);
- if (!next_closer_domain)
- return -ENOMEM;
+ r = nsec3_hashed_domain_make(enclosure_rr, pp, zone, &next_closer_domain);
+ if (r < 0)
+ return r;
+ if (r != hashed_size)
+ return -EBADMSG;
DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) {
- _cleanup_free_ char *label = NULL, *next_hashed_domain = NULL;
+ _cleanup_free_ char *next_hashed_domain = NULL;
- r = nsec3_is_good(rr, flags, suffix_rr);
+ r = nsec3_is_good(rr, zone_rr);
if (r < 0)
return r;
if (r == 0)
continue;
- label = base32hexmem(rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size, false);
- if (!label)
- return -ENOMEM;
-
- next_hashed_domain = strjoin(label, ".", p, NULL);
- if (!next_hashed_domain)
- return -ENOMEM;
+ r = nsec3_hashed_domain_format(rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size, zone, &next_hashed_domain);
+ if (r < 0)
+ return r;
r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), next_closer_domain, next_hashed_domain);
if (r < 0)
return r;
if (r > 0) {
if (rr->nsec3.flags & 1)
- *result = DNSSEC_NSEC_OPTOUT;
- else
- *result = DNSSEC_NSEC_NXDOMAIN;
+ optout = true;
- *authenticated = a && (flags & DNS_ANSWER_AUTHENTICATED);
- return 1;
+ a = a && (flags & DNS_ANSWER_AUTHENTICATED);
+
+ no_closer = true;
+ }
+
+ r = dns_name_equal(DNS_RESOURCE_KEY_NAME(rr->key), wildcard_domain);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ a = a && (flags & DNS_ANSWER_AUTHENTICATED);
+
+ wildcard_rr = rr;
+ }
+
+ r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), wildcard_domain, next_hashed_domain);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ if (rr->nsec3.flags & 1)
+ /* This only makes sense if we have a wildcard delegation, which is
+ * very unlikely, see RFC 4592, Section 4.2, but we cannot rely on
+ * this not happening, so hence cannot simply conclude NXDOMAIN as
+ * we would wish */
+ optout = true;
+
+ a = a && (flags & DNS_ANSWER_AUTHENTICATED);
+
+ no_wildcard = true;
}
}
- *result = DNSSEC_NSEC_NO_RR;
+ if (wildcard_rr && no_wildcard)
+ return -EBADMSG;
+
+ if (!no_closer) {
+ *result = DNSSEC_NSEC_NO_RR;
+ return 0;
+ }
+
+ if (wildcard_rr) {
+ /* A wildcard exists that matches our query. */
+ if (optout)
+ /* This is not specified in any RFC to the best of my knowledge, but
+ * if the next closer enclosure is covered by an opt-out NSEC3 RR
+ * it means that we cannot prove that the source of synthesis is
+ * correct, as there may be a closer match. */
+ *result = DNSSEC_NSEC_OPTOUT;
+ else if (bitmap_isset(wildcard_rr->nsec3.types, key->type))
+ *result = DNSSEC_NSEC_FOUND;
+ else if (bitmap_isset(wildcard_rr->nsec3.types, DNS_TYPE_CNAME))
+ *result = DNSSEC_NSEC_CNAME;
+ else
+ *result = DNSSEC_NSEC_NODATA;
+ } else {
+ if (optout)
+ /* The RFC only specifies that we have to care for optout for NODATA for
+ * DS records. However, children of an insecure opt-out delegation should
+ * also be considered opt-out, rather than verified NXDOMAIN.
+ * Note that we do not require a proof of wildcard non-existence if the
+ * next closer domain is covered by an opt-out, as that would not provide
+ * any additional information. */
+ *result = DNSSEC_NSEC_OPTOUT;
+ else if (no_wildcard)
+ *result = DNSSEC_NSEC_NXDOMAIN;
+ else {
+ *result = DNSSEC_NSEC_NO_RR;
+
+ return 0;
+ }
+ }
+
+ if (authenticated)
+ *authenticated = a;
+
+ if (ttl)
+ *ttl = enclosure_rr->ttl;
+
return 0;
}
-int dnssec_test_nsec(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated) {
+int dnssec_nsec_test(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl) {
DnsResourceRecord *rr;
bool have_nsec3 = false;
DnsAnswerFlags flags;
assert(key);
assert(result);
- assert(authenticated);
/* Look for any NSEC/NSEC3 RRs that say something about the specified key. */
if (r < 0)
return r;
if (r > 0) {
- *result = bitmap_isset(rr->nsec.types, key->type) ? DNSSEC_NSEC_FOUND : DNSSEC_NSEC_NODATA;
- *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+ if (bitmap_isset(rr->nsec.types, key->type))
+ *result = DNSSEC_NSEC_FOUND;
+ else if (bitmap_isset(rr->nsec.types, DNS_TYPE_CNAME))
+ *result = DNSSEC_NSEC_CNAME;
+ else
+ *result = DNSSEC_NSEC_NODATA;
+
+ if (authenticated)
+ *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+ if (ttl)
+ *ttl = rr->ttl;
+
return 0;
}
return r;
if (r > 0) {
*result = DNSSEC_NSEC_NXDOMAIN;
- *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+
+ if (authenticated)
+ *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+ if (ttl)
+ *ttl = rr->ttl;
+
return 0;
}
break;
/* OK, this was not sufficient. Let's see if NSEC3 can help. */
if (have_nsec3)
- return dnssec_test_nsec3(answer, key, result, authenticated);
+ return dnssec_test_nsec3(answer, key, result, authenticated, ttl);
/* 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_DOWNGRADE_OK] = "downgrade-ok",
- [DNSSEC_YES] = "yes",
-};
-DEFINE_STRING_TABLE_LOOKUP(dnssec_mode, DnssecMode);
+int dnssec_nsec_test_between(DnsAnswer *answer, const char *name, const char *zone, bool *authenticated) {
+ DnsResourceRecord *rr;
+ DnsAnswerFlags flags;
+ int r;
+
+ assert(name);
+ assert(zone);
+
+ /* Checks whether there's an NSEC/NSEC3 that proves that the specified 'name' is non-existing in the specified
+ * 'zone'. The 'zone' must be a suffix of the 'name'. */
+
+ DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) {
+ bool found = false;
+
+ r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rr->key), zone);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ switch (rr->key->type) {
+
+ case DNS_TYPE_NSEC:
+ r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), name, rr->nsec.next_domain_name);
+ if (r < 0)
+ return r;
+
+ found = r > 0;
+ break;
+
+ case DNS_TYPE_NSEC3: {
+ _cleanup_free_ char *hashed_domain = NULL, *next_hashed_domain = NULL;
+
+ r = nsec3_is_good(rr, NULL);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+
+ /* Format the domain we are testing with the NSEC3 RR's hash function */
+ r = nsec3_hashed_domain_make(
+ rr,
+ name,
+ zone,
+ &hashed_domain);
+ if (r < 0)
+ return r;
+ if ((size_t) r != rr->nsec3.next_hashed_name_size)
+ break;
+
+ /* Format the NSEC3's next hashed name as proper domain name */
+ r = nsec3_hashed_domain_format(
+ rr->nsec3.next_hashed_name,
+ rr->nsec3.next_hashed_name_size,
+ zone,
+ &next_hashed_domain);
+ if (r < 0)
+ return r;
+
+ r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), hashed_domain, next_hashed_domain);
+ if (r < 0)
+ return r;
+
+ found = r > 0;
+ break;
+ }
+
+ default:
+ continue;
+ }
+
+ if (found) {
+ if (authenticated)
+ *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+ return 1;
+ }
+ }
+
+ return 0;
+}
static const char* const dnssec_result_table[_DNSSEC_RESULT_MAX] = {
[DNSSEC_VALIDATED] = "validated",
+ [DNSSEC_VALIDATED_WILDCARD] = "validated-wildcard",
[DNSSEC_INVALID] = "invalid",
[DNSSEC_SIGNATURE_EXPIRED] = "signature-expired",
[DNSSEC_UNSUPPORTED_ALGORITHM] = "unsupported-algorithm",
projects / thirdparty / systemd.git / blobdiff