#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"
*
* TODO:
*
- * - Iterative validation
- * - NSEC proof of non-existance
- * - NSEC3 proof of non-existance
- * - Make trust anchor store read additional DS+DNSKEY data from disk
- * - wildcard zones compatibility
+ * - wildcard zones compatibility (NSEC/NSEC3 wildcard check is missing)
* - multi-label zone compatibility
- * - DNSSEC cname/dname compatibility
+ * - cname/dname compatibility
* - per-interface DNSSEC setting
- * - DSA support
- * - EC support?
+ * - nxdomain on qname
+ * - retry on failed validation?
+ * - DNSSEC key revocation support? https://tools.ietf.org/html/rfc5011
+ * - when doing negative caching, use NSEC/NSEC3 RR instead of SOA for TTL
*
* */
/* 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. */
+#define NSEC3_ITERATIONS_MAX 2048
+
/*
* The DNSSEC Chain of trust:
*
* Normal RR → RRSIG/DNSKEY+ → DS → RRSIG/DNSKEY+ → DS → ... → DS → RRSIG/DNSKEY+ → DS
*/
-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);
-}
+static void initialize_libgcrypt(void) {
+ const char *p;
+
+ if (gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P))
+ return;
+
+ p = gcry_check_version("1.4.5");
+ assert(p);
-static bool dnssec_digest_supported(int digest) {
- return IN_SET(digest,
- DNSSEC_DIGEST_SHA1,
- DNSSEC_DIGEST_SHA256);
+ gcry_control(GCRYCTL_DISABLE_SECMEM);
+ gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
}
uint16_t dnssec_keytag(DnsResourceRecord *dnskey) {
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));
}
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,
DnsResourceRecord *rrsig,
DnsResourceRecord *dnskey,
- usec_t realtime) {
+ 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;
assert(key);
assert(rrsig);
assert(dnskey);
+ assert(result);
assert(rrsig->key->type == DNS_TYPE_RRSIG);
assert(dnskey->key->type == DNS_TYPE_DNSKEY);
* using the signature "rrsig" and the key "dnskey". It's
* assumed the RRSIG and DNSKEY match. */
- if (!dnssec_algorithm_supported(rrsig->rrsig.algorithm))
- return -EOPNOTSUPP;
-
- if (a->n_rrs > VERIFY_RRS_MAX)
- return -E2BIG;
+ md_algorithm = algorithm_to_gcrypt_md(rrsig->rrsig.algorithm);
+ if (md_algorithm == -EOPNOTSUPP) {
+ *result = DNSSEC_UNSUPPORTED_ALGORITHM;
+ return 0;
+ }
+ if (md_algorithm < 0)
+ return md_algorithm;
r = dnssec_rrsig_expired(rrsig, realtime);
if (r < 0)
return r;
- if (r > 0)
- return DNSSEC_SIGNATURE_EXPIRED;
+ if (r > 0) {
+ *result = DNSSEC_SIGNATURE_EXPIRED;
+ return 0;
+ }
/* Collect all relevant RRs in a single array, so that we can look at the RRset */
list = newa(DnsResourceRecord *, a->n_rrs);
return r;
list[n++] = rr;
+
+ if (n > VERIFY_RRS_MAX)
+ return -E2BIG;
}
if (n <= 0)
qsort_safe(list, n, sizeof(DnsResourceRecord*), rr_compare);
/* 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;
+ initialize_libgcrypt();
- case DNSSEC_ALGORITHM_RSASHA512:
- gcry_md_open(&md, GCRY_MD_SHA512, 0);
- hash_size = 64;
- break;
-
- 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;
gcry_md_write(md, wire_format_name, r);
for (k = 0; k < n; k++) {
+ const char *suffix;
size_t l;
rr = list[k];
- r = dns_name_to_wire_format(DNS_RESOURCE_KEY_NAME(rr->key), wire_format_name, sizeof(wire_format_name), true);
+ 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! */
+ 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->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;
- r = r ? DNSSEC_VERIFIED : DNSSEC_INVALID;
+ *result = r ? DNSSEC_VALIDATED : DNSSEC_INVALID;
+ r = 0;
finish:
gcry_md_close(md);
return 0;
if ((dnskey->dnskey.flags & DNSKEY_FLAG_ZONE_KEY) == 0)
return 0;
+ if ((dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE))
+ return 0;
if (dnskey->dnskey.protocol != 3)
return 0;
if (dnskey->dnskey.algorithm != rrsig->rrsig.algorithm)
return dns_name_equal(DNS_RESOURCE_KEY_NAME(dnskey->key), rrsig->rrsig.signer);
}
-int dnssec_key_match_rrsig(DnsResourceKey *key, DnsResourceRecord *rrsig) {
+int dnssec_key_match_rrsig(const DnsResourceKey *key, DnsResourceRecord *rrsig) {
+ int r;
+
assert(key);
assert(rrsig);
if (rrsig->rrsig.type_covered != key->type)
return 0;
+ /* Make sure signer is a parent of the RRset */
+ r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rrsig->key), rrsig->rrsig.signer);
+ if (r <= 0)
+ return r;
+
+ /* Make sure the owner name has at least as many labels as the "label" fields indicates. */
+ r = dns_name_count_labels(DNS_RESOURCE_KEY_NAME(rrsig->key));
+ if (r < 0)
+ return r;
+ if (r < rrsig->rrsig.labels)
+ return 0;
+
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,
DnsAnswer *validated_dnskeys,
- usec_t realtime) {
+ usec_t realtime,
+ DnssecResult *result) {
- bool found_rrsig = false, found_dnskey = false;
+ bool found_rrsig = false, found_invalid = false, found_expired_rrsig = false, found_unsupported_algorithm = false;
DnsResourceRecord *rrsig;
int r;
assert(key);
+ assert(result);
- /* Verifies all RRs from "a" that match the key "key", against DNSKEY and DS RRs in "validated_dnskeys" */
+ /* Verifies all RRs from "a" that match the key "key" against DNSKEYs in "validated_dnskeys" */
if (!a || a->n_rrs <= 0)
return -ENODATA;
/* Iterate through each RRSIG RR. */
DNS_ANSWER_FOREACH(rrsig, a) {
DnsResourceRecord *dnskey;
+ DnsAnswerFlags flags;
+ /* Is this an RRSIG RR that applies to RRs matching our key? */
r = dnssec_key_match_rrsig(key, rrsig);
if (r < 0)
return r;
found_rrsig = true;
- DNS_ANSWER_FOREACH(dnskey, validated_dnskeys) {
+ /* Look for a matching key */
+ DNS_ANSWER_FOREACH_FLAGS(dnskey, flags, validated_dnskeys) {
+ DnssecResult one_result;
+ if ((flags & DNS_ANSWER_AUTHENTICATED) == 0)
+ continue;
+
+ /* Is this a DNSKEY RR that matches they key of our RRSIG? */
r = dnssec_rrsig_match_dnskey(rrsig, dnskey);
if (r < 0)
return r;
if (r == 0)
continue;
- found_dnskey = true;
-
/* Take the time here, if it isn't set yet, so
* that we do all validations with the same
* time. */
* the RRSet against the RRSIG and DNSKEY
* combination. */
- r = dnssec_verify_rrset(a, key, rrsig, dnskey, realtime);
- if (r < 0 && r != EOPNOTSUPP)
+ r = dnssec_verify_rrset(a, key, rrsig, dnskey, realtime, &one_result);
+ if (r < 0)
return r;
- if (r == DNSSEC_VERIFIED)
- return DNSSEC_VERIFIED;
-
- /* If the signature is invalid, or done using
- an unsupported algorithm, let's try another
- key and/or signature. After all they
- key_tags and stuff are not unique, and
- might be shared by multiple keys. */
+
+ switch (one_result) {
+
+ case DNSSEC_VALIDATED:
+ /* Yay, the RR has been validated,
+ * return immediately, but fix up the expiry */
+ r = dnssec_fix_rrset_ttl(a, key, rrsig, realtime);
+ if (r < 0)
+ return r;
+
+ *result = DNSSEC_VALIDATED;
+ return 0;
+
+ case DNSSEC_INVALID:
+ /* If the signature is invalid, let's try another
+ key and/or signature. After all they
+ key_tags and stuff are not unique, and
+ might be shared by multiple keys. */
+ found_invalid = true;
+ continue;
+
+ case DNSSEC_UNSUPPORTED_ALGORITHM:
+ /* If the key algorithm is
+ unsupported, try another
+ RRSIG/DNSKEY pair, but remember we
+ encountered this, so that we can
+ return a proper error when we
+ encounter nothing better. */
+ found_unsupported_algorithm = true;
+ continue;
+
+ case DNSSEC_SIGNATURE_EXPIRED:
+ /* If the signature is expired, try
+ another one, but remember it, so
+ that we can return this */
+ found_expired_rrsig = true;
+ continue;
+
+ default:
+ assert_not_reached("Unexpected DNSSEC validation result");
+ }
}
}
- if (found_dnskey)
- return DNSSEC_INVALID;
+ if (found_expired_rrsig)
+ *result = DNSSEC_SIGNATURE_EXPIRED;
+ else if (found_unsupported_algorithm)
+ *result = DNSSEC_UNSUPPORTED_ALGORITHM;
+ else if (found_invalid)
+ *result = DNSSEC_INVALID;
+ else if (found_rrsig)
+ *result = DNSSEC_MISSING_KEY;
+ else
+ *result = DNSSEC_NO_SIGNATURE;
+
+ return 0;
+}
+
+int dnssec_has_rrsig(DnsAnswer *a, const DnsResourceKey *key) {
+ DnsResourceRecord *rr;
+ int r;
+
+ /* Checks whether there's at least one RRSIG in 'a' that proctects RRs of the specified key */
- if (found_rrsig)
- return DNSSEC_MISSING_KEY;
+ DNS_ANSWER_FOREACH(rr, a) {
+ r = dnssec_key_match_rrsig(key, rr);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return 1;
+ }
- return DNSSEC_NO_SIGNATURE;
+ return 0;
}
int dnssec_canonicalize(const char *n, char *buffer, size_t buffer_max) {
return (int) c;
}
-int dnssec_verify_dnskey(DnsResourceRecord *dnskey, DnsResourceRecord *ds) {
- gcry_md_hd_t md = NULL;
+static int digest_to_gcrypt_md(uint8_t algorithm) {
+
+ /* Translates a DNSSEC digest algorithm into a gcrypt digest identifier */
+
+ switch (algorithm) {
+
+ case DNSSEC_DIGEST_SHA1:
+ return GCRY_MD_SHA1;
+
+ 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) {
char owner_name[DNSSEC_CANONICAL_HOSTNAME_MAX];
+ gcry_md_hd_t md = NULL;
+ size_t hash_size;
+ int md_algorithm, r;
void *result;
- int r;
assert(dnskey);
assert(ds);
if (dnskey->dnskey.protocol != 3)
return -EKEYREJECTED;
- if (!dnssec_algorithm_supported(dnskey->dnskey.algorithm))
- return -EOPNOTSUPP;
- if (!dnssec_digest_supported(ds->ds.digest_type))
- return -EOPNOTSUPP;
-
if (dnskey->dnskey.algorithm != ds->ds.algorithm)
return 0;
if (dnssec_keytag(dnskey) != ds->ds.key_tag)
return 0;
- switch (ds->ds.digest_type) {
+ initialize_libgcrypt();
- case DNSSEC_DIGEST_SHA1:
+ md_algorithm = digest_to_gcrypt_md(ds->ds.digest_type);
+ if (md_algorithm < 0)
+ return md_algorithm;
- if (ds->ds.digest_size != 20)
- return 0;
-
- gcry_md_open(&md, GCRY_MD_SHA1, 0);
- break;
-
- case DNSSEC_DIGEST_SHA256:
-
- if (ds->ds.digest_size != 32)
- return 0;
+ hash_size = gcry_md_get_algo_dlen(md_algorithm);
+ assert(hash_size > 0);
- gcry_md_open(&md, GCRY_MD_SHA256, 0);
- break;
+ if (ds->ds.digest_size != hash_size)
+ return 0;
- default:
- assert_not_reached("Unknown digest");
- }
+ r = dnssec_canonicalize(DNS_RESOURCE_KEY_NAME(dnskey->key), owner_name, sizeof(owner_name));
+ if (r < 0)
+ return r;
+ gcry_md_open(&md, md_algorithm, 0);
if (!md)
return -EIO;
- r = dnssec_canonicalize(DNS_RESOURCE_KEY_NAME(dnskey->key), owner_name, sizeof(owner_name));
- if (r < 0)
- goto finish;
-
gcry_md_write(md, owner_name, r);
md_add_uint16(md, dnskey->dnskey.flags);
md_add_uint8(md, dnskey->dnskey.protocol);
return r;
}
+int dnssec_verify_dnskey_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ds) {
+ DnsResourceRecord *ds;
+ DnsAnswerFlags flags;
+ int r;
+
+ assert(dnskey);
+
+ if (dnskey->key->type != DNS_TYPE_DNSKEY)
+ return 0;
+
+ DNS_ANSWER_FOREACH_FLAGS(ds, flags, validated_ds) {
+
+ if ((flags & DNS_ANSWER_AUTHENTICATED) == 0)
+ continue;
+
+ if (ds->key->type != DNS_TYPE_DS)
+ continue;
+
+ if (ds->key->class != dnskey->key->class)
+ continue;
+
+ r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dnskey->key), DNS_RESOURCE_KEY_NAME(ds->key));
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ r = dnssec_verify_dnskey(dnskey, ds);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ return 1;
+ }
+
+ 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;
+ 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;
+
+ 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;
+
+ 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;
+}
+
+static int nsec3_is_good(DnsResourceRecord *rr, DnsAnswerFlags flags, DnsResourceRecord *nsec3) {
+ const char *a, *b;
+ int r;
+
+ assert(rr);
+
+ if (rr->key->type != DNS_TYPE_NSEC3)
+ return 0;
+
+ /* RFC 5155, Section 8.2 says we MUST ignore NSEC3 RRs with flags != 0 or 1 */
+ 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;
+
+ /* If a second NSEC3 RR is specified, also check if they are from the same zone. */
+
+ if (nsec3 == rr) /* Shortcut */
+ return 1;
+
+ if (rr->key->class != nsec3->key->class)
+ return 0;
+ if (rr->nsec3.algorithm != nsec3->nsec3.algorithm)
+ return 0;
+ if (rr->nsec3.iterations != nsec3->nsec3.iterations)
+ return 0;
+ if (rr->nsec3.salt_size != nsec3->nsec3.salt_size)
+ return 0;
+ if (memcmp(rr->nsec3.salt, nsec3->nsec3.salt, rr->nsec3.salt_size) != 0)
+ return 0;
+
+ a = DNS_RESOURCE_KEY_NAME(rr->key);
+ r = dns_name_parent(&a); /* strip off hash */
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return 0;
+
+ b = DNS_RESOURCE_KEY_NAME(nsec3->key);
+ r = dns_name_parent(&b); /* strip off hash */
+ if (r < 0)
+ return r;
+ if (r == 0)
+ return 0;
+
+ return dns_name_equal(a, b);
+}
+
+static int nsec3_hashed_domain(DnsResourceRecord *nsec3, const char *domain, const char *zone, char **ret) {
+ _cleanup_free_ char *l = NULL, *hashed_domain = NULL;
+ uint8_t hashed[DNSSEC_HASH_SIZE_MAX];
+ 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;
+
+ l = base32hexmem(hashed, hashed_size, false);
+ if (!l)
+ return -ENOMEM;
+
+ hashed_domain = strjoin(l, ".", zone, NULL);
+ if (!hashed_domain)
+ return -ENOMEM;
+
+ *ret = hashed_domain;
+ hashed_domain = NULL;
+
+ return hashed_size;
+}
+
+/* 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) {
+ _cleanup_free_ char *next_closer_domain = NULL, *wildcard = NULL, *wildcard_domain = NULL;
+ const char *zone, *p, *pp = NULL;
+ DnsResourceRecord *rr, *enclosure_rr, *suffix_rr, *wildcard_rr = NULL;
+ DnsAnswerFlags flags;
+ int hashed_size, r;
+ bool a, no_closer = false, no_wildcard = false, optout = false;
+
+ assert(key);
+ assert(result);
+ assert(authenticated);
+
+ /* 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);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ r = dns_name_equal_skip(DNS_RESOURCE_KEY_NAME(suffix_rr->key), 1, zone);
+ if (r < 0)
+ return r;
+ if (r > 0)
+ goto found_zone;
+ }
+
+ /* Strip one label from the front */
+ r = dns_name_parent(&zone);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+ }
+
+ *result = DNSSEC_NSEC_NO_RR;
+ return 0;
+
+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;
+
+ hashed_size = nsec3_hashed_domain(suffix_rr, p, zone, &hashed_domain);
+ if (hashed_size == -EOPNOTSUPP) {
+ *result = DNSSEC_NSEC_UNSUPPORTED_ALGORITHM;
+ return 0;
+ }
+ if (hashed_size < 0)
+ return hashed_size;
+
+ DNS_ANSWER_FOREACH_FLAGS(enclosure_rr, flags, answer) {
+
+ r = nsec3_is_good(enclosure_rr, flags, suffix_rr);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ continue;
+
+ if (enclosure_rr->nsec3.next_hashed_name_size != (size_t) hashed_size)
+ continue;
+
+ r = dns_name_equal(DNS_RESOURCE_KEY_NAME(enclosure_rr->key), hashed_domain);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ a = flags & DNS_ANSWER_AUTHENTICATED;
+ goto found_closest_encloser;
+ }
+ }
+
+ /* We didn't find the closest encloser with this name,
+ * but let's remember this domain name, it might be
+ * the next closer name */
+
+ pp = p;
+
+ /* Strip one label from the front */
+ r = dns_name_parent(&p);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ break;
+ }
+
+ *result = DNSSEC_NSEC_NO_RR;
+ return 0;
+
+found_closest_encloser:
+ /* 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(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(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. */
+ 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;
+
+ *authenticated = a;
+
+ return 0;
+ }
+
+ /* Prove that there is no next closer and whether or not there is a wildcard domain. */
+
+ wildcard = strappend("*.", p);
+ if (!wildcard)
+ return -ENOMEM;
+
+ r = nsec3_hashed_domain(enclosure_rr, wildcard, zone, &wildcard_domain);
+ if (r < 0)
+ return r;
+ if (r != hashed_size)
+ return -EBADMSG;
+
+ r = nsec3_hashed_domain(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;
+
+ r = nsec3_is_good(rr, flags, suffix_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, ".", zone, NULL);
+ if (!next_hashed_domain)
+ return -ENOMEM;
+
+ 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)
+ optout = true;
+
+ 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;
+ }
+ }
+
+ 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;
+ }
+ }
+
+ *authenticated = a;
+
+ return 0;
+}
+
+int dnssec_test_nsec(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated) {
+ DnsResourceRecord *rr;
+ bool have_nsec3 = false;
+ DnsAnswerFlags flags;
+ int r;
+
+ assert(key);
+ assert(result);
+ assert(authenticated);
+
+ /* Look for any NSEC/NSEC3 RRs that say something about the specified key. */
+
+ DNS_ANSWER_FOREACH_FLAGS(rr, flags, 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) {
+ 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;
+ *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+ 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;
+ *authenticated = flags & DNS_ANSWER_AUTHENTICATED;
+ return 0;
+ }
+ break;
+
+ case DNS_TYPE_NSEC3:
+ have_nsec3 = true;
+ break;
+ }
+ }
+
+ /* OK, this was not sufficient. Let's see if NSEC3 can help. */
+ if (have_nsec3)
+ return dnssec_test_nsec3(answer, key, result, authenticated);
+
+ /* 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",
+ [DNSSEC_DOWNGRADE_OK] = "downgrade-ok",
[DNSSEC_YES] = "yes",
};
DEFINE_STRING_TABLE_LOOKUP(dnssec_mode, DnssecMode);
+
+static const char* const dnssec_result_table[_DNSSEC_RESULT_MAX] = {
+ [DNSSEC_VALIDATED] = "validated",
+ [DNSSEC_INVALID] = "invalid",
+ [DNSSEC_SIGNATURE_EXPIRED] = "signature-expired",
+ [DNSSEC_UNSUPPORTED_ALGORITHM] = "unsupported-algorithm",
+ [DNSSEC_NO_SIGNATURE] = "no-signature",
+ [DNSSEC_MISSING_KEY] = "missing-key",
+ [DNSSEC_UNSIGNED] = "unsigned",
+ [DNSSEC_FAILED_AUXILIARY] = "failed-auxiliary",
+ [DNSSEC_NSEC_MISMATCH] = "nsec-mismatch",
+ [DNSSEC_INCOMPATIBLE_SERVER] = "incompatible-server",
+};
+DEFINE_STRING_TABLE_LOOKUP(dnssec_result, DnssecResult);
projects / thirdparty / systemd.git / blobdiff