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Merge pull request #14930 from tomhughes/dnssec-canonicalise 

Canonicalise names in DNS responses per RFC4034 requirements
This commit is contained in:
Lennart Poettering 2020-04-07 17:07:04 +02:00 committed by GitHub
parent cabc1c6d7a 4e58741d55
commit 9afe05c149
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 136 additions and 78 deletions
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49
src/resolve/resolved-dns-dnssec.c
View File

@ -59,55 +59,6 @@ uint16_t dnssec_keytag(DnsResourceRecord *dnskey, bool mask_revoke) {
return sum & UINT32_C(0xFFFF);
}
int dnssec_canonicalize(const char *n, char *buffer, size_t buffer_max) {
size_t c = 0;
int r;
/* Converts the specified hostname into DNSSEC canonicalized
* form. */
if (buffer_max < 2)
return -ENOBUFS;
for (;;) {
r = dns_label_unescape(&n, buffer, buffer_max, 0);
if (r < 0)
return r;
if (r == 0)
break;
if (buffer_max < (size_t) r + 2)
return -ENOBUFS;
/* The DNSSEC canonical form is not clear on what to
* do with dots appearing in labels, the way DNS-SD
* does it. Refuse it for now. */
if (memchr(buffer, '.', r))
return -EINVAL;
ascii_strlower_n(buffer, (size_t) r);
buffer[r] = '.';
buffer += r + 1;
c += r + 1;
buffer_max -= r + 1;
}
if (c <= 0) {
/* Not even a single label: this is the root domain name */
assert(buffer_max > 2);
buffer[0] = '.';
buffer[1] = 0;
return 1;
}
return (int) c;
}
#if HAVE_GCRYPT
static int rr_compare(DnsResourceRecord * const *a, DnsResourceRecord * const *b) {

2
src/resolve/resolved-dns-dnssec.h
View File

@ -58,8 +58,6 @@ int dnssec_has_rrsig(DnsAnswer *a, const DnsResourceKey *key);
uint16_t dnssec_keytag(DnsResourceRecord *dnskey, bool mask_revoke);
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 {

10
src/resolve/resolved-dns-packet.c
View File

@ -856,14 +856,14 @@ int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, const DnsAns
/* RFC 2782 states "Unless and until permitted by future standards
* action, name compression is not to be used for this field." */
r = dns_packet_append_name(p, rr->srv.name, false, false, NULL);
r = dns_packet_append_name(p, rr->srv.name, false, true, NULL);
break;
case DNS_TYPE_PTR:
case DNS_TYPE_NS:
case DNS_TYPE_CNAME:
case DNS_TYPE_DNAME:
r = dns_packet_append_name(p, rr->ptr.name, true, false, NULL);
r = dns_packet_append_name(p, rr->ptr.name, true, true, NULL);
break;
case DNS_TYPE_HINFO:
@ -906,11 +906,11 @@ int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, const DnsAns
break;
case DNS_TYPE_SOA:
r = dns_packet_append_name(p, rr->soa.mname, true, false, NULL);
r = dns_packet_append_name(p, rr->soa.mname, true, true, NULL);
if (r < 0)
goto fail;
r = dns_packet_append_name(p, rr->soa.rname, true, false, NULL);
r = dns_packet_append_name(p, rr->soa.rname, true, true, NULL);
if (r < 0)
goto fail;
@ -938,7 +938,7 @@ int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, const DnsAns
if (r < 0)
goto fail;
r = dns_packet_append_name(p, rr->mx.exchange, true, false, NULL);
r = dns_packet_append_name(p, rr->mx.exchange, true, true, NULL);
break;
case DNS_TYPE_LOC:

153
src/resolve/test-dnssec.c
View File

@ -13,26 +13,6 @@
#include "string-util.h"
#include "hexdecoct.h"
static void test_dnssec_canonicalize_one(const char *original, const char *canonical, int r) {
char canonicalized[DNSSEC_CANONICAL_HOSTNAME_MAX];
assert_se(dnssec_canonicalize(original, canonicalized, sizeof(canonicalized)) == r);
if (r < 0)
return;
assert_se(streq(canonicalized, canonical));
}
static void test_dnssec_canonicalize(void) {
test_dnssec_canonicalize_one("", ".", 1);
test_dnssec_canonicalize_one(".", ".", 1);
test_dnssec_canonicalize_one("foo", "foo.", 4);
test_dnssec_canonicalize_one("foo.", "foo.", 4);
test_dnssec_canonicalize_one("FOO.", "foo.", 4);
test_dnssec_canonicalize_one("FOO.bar.", "foo.bar.", 8);
test_dnssec_canonicalize_one("FOO..bar.", NULL, -EINVAL);
}
#if HAVE_GCRYPT
static void test_dnssec_verify_dns_key(void) {
@ -463,6 +443,136 @@ static void test_dnssec_verify_rrset2(void) {
assert_se(result == DNSSEC_VALIDATED);
}
static void test_dnssec_verify_rrset3(void) {
static const uint8_t signature_blob[] = {
0x41, 0x09, 0x08, 0x67, 0x51, 0x6d, 0x02, 0xf2, 0x17, 0x1e, 0x61, 0x03, 0xc6, 0x80, 0x7a, 0x82,
0x8f, 0x6c, 0x8c, 0x4c, 0x68, 0x6f, 0x1c, 0xaa, 0x4a, 0xe0, 0x9b, 0x72, 0xdf, 0x7f, 0x15, 0xfa,
0x2b, 0xc5, 0x63, 0x6f, 0x52, 0xa2, 0x60, 0x59, 0x24, 0xb6, 0xc3, 0x43, 0x3d, 0x47, 0x38, 0xd8,
0x0c, 0xcc, 0x6c, 0x10, 0x49, 0x92, 0x97, 0x6c, 0x7d, 0x32, 0xc2, 0x62, 0x83, 0x34, 0x96, 0xdf,
0xbd, 0xf9, 0xcc, 0xcf, 0xd9, 0x4d, 0x8b, 0x8a, 0xa9, 0x3c, 0x1f, 0x89, 0xc4, 0xad, 0xd5, 0xbb,
0x74, 0xf8, 0xee, 0x60, 0x54, 0x7a, 0xec, 0x36, 0x45, 0xf2, 0xec, 0xb9, 0x73, 0x66, 0xae, 0x57,
0x2d, 0xd4, 0x91, 0x02, 0x99, 0xcd, 0xba, 0xbd, 0x6e, 0xfb, 0xa6, 0xf6, 0x34, 0xce, 0x4c, 0x44,
0x0b, 0xd2, 0x66, 0xdb, 0x4e, 0x5e, 0x00, 0x72, 0x1b, 0xe5, 0x2f, 0x24, 0xd2, 0xc8, 0x72, 0x37,
0x97, 0x2b, 0xd0, 0xcd, 0xa9, 0x6b, 0x84, 0x32, 0x56, 0x7a, 0x89, 0x6e, 0x3d, 0x8f, 0x03, 0x9a,
0x9d, 0x6d, 0xf7, 0xe5, 0x13, 0xd7, 0x4b, 0xbc, 0xe2, 0x6c, 0xd1, 0x18, 0x60, 0x0e, 0x1a, 0xe3,
0xf9, 0xc0, 0x34, 0x4b, 0x1c, 0x82, 0x17, 0x5e, 0xdf, 0x81, 0x32, 0xd7, 0x5b, 0x30, 0x1d, 0xe0,
0x29, 0x80, 0x6b, 0xb1, 0x69, 0xbf, 0x3f, 0x12, 0x56, 0xb0, 0x80, 0x91, 0x22, 0x1a, 0x31, 0xd5,
0x5d, 0x3d, 0xdd, 0x70, 0x5e, 0xcb, 0xc7, 0x2d, 0xb8, 0x3e, 0x54, 0x34, 0xd3, 0x50, 0x89, 0x77,
0x08, 0xc1, 0xf7, 0x11, 0x6e, 0x57, 0xd7, 0x09, 0x94, 0x20, 0x03, 0x38, 0xc3, 0x3a, 0xd3, 0x93,
0x8f, 0xd0, 0x65, 0xc5, 0xa1, 0xe0, 0x69, 0x2c, 0xf6, 0x0a, 0xce, 0x01, 0xb6, 0x0d, 0x95, 0xa0,
0x5d, 0x97, 0x94, 0xc3, 0xf1, 0xcd, 0x49, 0xea, 0x20, 0xd3, 0xa9, 0xa6, 0x67, 0x94, 0x64, 0x17
};
static const uint8_t dnskey_blob[] = {
0x03, 0x01, 0x00, 0x01, 0xbf, 0xdd, 0x24, 0x95, 0x21, 0x70, 0xa8, 0x5b, 0x19, 0xa6, 0x76, 0xd3,
0x5b, 0x37, 0xcf, 0x59, 0x0d, 0x3c, 0xdb, 0x0c, 0xcf, 0xd6, 0x19, 0x02, 0xc7, 0x8e, 0x56, 0x4d,
0x14, 0xb7, 0x9d, 0x71, 0xf4, 0xdd, 0x24, 0x36, 0xc8, 0x32, 0x1c, 0x63, 0xf7, 0xc0, 0xfc, 0xe3,
0x83, 0xa6, 0x22, 0x8b, 0x6a, 0x34, 0x41, 0x72, 0xaa, 0x95, 0x98, 0x06, 0xac, 0x03, 0xec, 0xc3,
0xa1, 0x6d, 0x8b, 0x1b, 0xfd, 0xa4, 0x05, 0x72, 0xe6, 0xe0, 0xb9, 0x98, 0x07, 0x54, 0x7a, 0xb2,
0x55, 0x30, 0x96, 0xa3, 0x22, 0x3b, 0xe0, 0x9d, 0x61, 0xf6, 0xdc, 0x31, 0x2b, 0xc9, 0x2c, 0x12,
0x06, 0x7f, 0x3c, 0x5d, 0x29, 0x76, 0x01, 0x62, 0xe3, 0x41, 0x41, 0x4f, 0xa6, 0x07, 0xfa, 0x2d,
0x0c, 0x64, 0x88, 0xd1, 0x56, 0x18, 0x4b, 0x2b, 0xc2, 0x19, 0x7e, 0xd0, 0x1a, 0x8c, 0x2d, 0x8d,
0x06, 0xdf, 0x4d, 0xaf, 0xd9, 0xe3, 0x31, 0x59, 0xbc, 0xc3, 0x36, 0x22, 0xe7, 0x15, 0xf9, 0xb2,
0x44, 0x8a, 0x33, 0xd7, 0x6c, 0xf1, 0xcc, 0x37, 0x05, 0x69, 0x32, 0x71, 0x76, 0xd8, 0x50, 0x06,
0xae, 0x27, 0xed, 0x3b, 0xdb, 0x1a, 0x97, 0x9b, 0xa3, 0x3e, 0x40, 0x42, 0x29, 0xaf, 0x75, 0x1c,
0xff, 0x1d, 0xaf, 0x85, 0x02, 0xb3, 0x2e, 0x99, 0x67, 0x08, 0x13, 0xd5, 0xda, 0x6d, 0x65, 0xb2,
0x36, 0x6f, 0x2f, 0x64, 0xe0, 0xfa, 0xd3, 0x81, 0x86, 0x6b, 0x41, 0x3e, 0x91, 0xaa, 0x0a, 0xd3,
0xb2, 0x92, 0xd9, 0x42, 0x36, 0x8a, 0x11, 0x0b, 0x5b, 0xb0, 0xea, 0xad, 0x76, 0xd5, 0xb4, 0x81,
0x30, 0xca, 0x5c, 0x4f, 0xd9, 0xea, 0xe7, 0x4b, 0x10, 0x0a, 0x09, 0x4b, 0x73, 0x66, 0xed, 0x8e,
0x84, 0xa2, 0x4f, 0x93, 0x7e, 0x29, 0xdc, 0x6a, 0xbd, 0x12, 0xa1, 0x3d, 0xd2, 0xd6, 0x2a, 0x67,
0x99, 0x4d, 0xf3, 0x43
};
_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *mx1 = NULL, *mx2 = NULL, *mx3 = NULL, *mx4 = NULL, *rrsig = NULL, *dnskey = NULL;
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
DnssecResult result;
mx1 = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_MX, "kodapan.se");
assert_se(mx1);
mx1->mx.priority = 1;
mx1->mx.exchange = strdup("ASPMX.L.GOOGLE.COM");
assert_se(mx1->mx.exchange);
log_info("MX: %s", strna(dns_resource_record_to_string(mx1)));
mx2 = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_MX, "kodapan.se");
assert_se(mx2);
mx2->mx.priority = 5;
mx2->mx.exchange = strdup("ALT2.ASPMX.L.GOOGLE.COM");
assert_se(mx2->mx.exchange);
log_info("MX: %s", strna(dns_resource_record_to_string(mx2)));
mx3 = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_MX, "kodapan.se");
assert_se(mx3);
mx3->mx.priority = 10;
mx3->mx.exchange = strdup("ASPMX2.GOOGLEMAIL.COM");
assert_se(mx3->mx.exchange);
log_info("MX: %s", strna(dns_resource_record_to_string(mx3)));
mx4 = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_MX, "kodapan.se");
assert_se(mx4);
mx4->mx.priority = 10;
mx4->mx.exchange = strdup("ASPMX3.GOOGLEMAIL.COM");
assert_se(mx4->mx.exchange);
log_info("MX: %s", strna(dns_resource_record_to_string(mx4)));
rrsig = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_RRSIG, "kodapan.se");
assert_se(rrsig);
rrsig->rrsig.type_covered = DNS_TYPE_MX;
rrsig->rrsig.algorithm = DNSSEC_ALGORITHM_RSASHA256;
rrsig->rrsig.labels = 2;
rrsig->rrsig.original_ttl = 900;
rrsig->rrsig.expiration = 0x5e608a84;
rrsig->rrsig.inception = 0x5e4e1584;
rrsig->rrsig.key_tag = 44028;
rrsig->rrsig.signer = strdup("kodapan.se.");
assert_se(rrsig->rrsig.signer);
rrsig->rrsig.signature_size = sizeof(signature_blob);
rrsig->rrsig.signature = memdup(signature_blob, rrsig->rrsig.signature_size);
assert_se(rrsig->rrsig.signature);
log_info("RRSIG: %s", strna(dns_resource_record_to_string(rrsig)));
dnskey = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, "kodapan.se");
assert_se(dnskey);
dnskey->dnskey.flags = 256;
dnskey->dnskey.protocol = 3;
dnskey->dnskey.algorithm = DNSSEC_ALGORITHM_RSASHA256;
dnskey->dnskey.key_size = sizeof(dnskey_blob);
dnskey->dnskey.key = memdup(dnskey_blob, sizeof(dnskey_blob));
assert_se(dnskey->dnskey.key);
log_info("DNSKEY: %s", strna(dns_resource_record_to_string(dnskey)));
log_info("DNSKEY keytag: %u", dnssec_keytag(dnskey, false));
assert_se(dnssec_key_match_rrsig(mx1->key, rrsig) > 0);
assert_se(dnssec_key_match_rrsig(mx2->key, rrsig) > 0);
assert_se(dnssec_key_match_rrsig(mx3->key, rrsig) > 0);
assert_se(dnssec_key_match_rrsig(mx4->key, rrsig) > 0);
assert_se(dnssec_rrsig_match_dnskey(rrsig, dnskey, false) > 0);
answer = dns_answer_new(4);
assert_se(answer);
assert_se(dns_answer_add(answer, mx1, 0, DNS_ANSWER_AUTHENTICATED) >= 0);
assert_se(dns_answer_add(answer, mx2, 0, DNS_ANSWER_AUTHENTICATED) >= 0);
assert_se(dns_answer_add(answer, mx3, 0, DNS_ANSWER_AUTHENTICATED) >= 0);
assert_se(dns_answer_add(answer, mx4, 0, DNS_ANSWER_AUTHENTICATED) >= 0);
/* Validate the RR as it if was 2020-02-24 today */
assert_se(dnssec_verify_rrset(answer, mx1->key, rrsig, dnskey, 1582534685*USEC_PER_SEC, &result) >= 0);
assert_se(result == DNSSEC_VALIDATED);
}
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 };
@ -499,14 +609,13 @@ static void test_dnssec_nsec3_hash(void) {
int main(int argc, char *argv[]) {
test_dnssec_canonicalize();
#if HAVE_GCRYPT
test_dnssec_verify_dns_key();
test_dnssec_verify_rfc8080_ed25519_example1();
test_dnssec_verify_rfc8080_ed25519_example2();
test_dnssec_verify_rrset();
test_dnssec_verify_rrset2();
test_dnssec_verify_rrset3();
test_dnssec_nsec3_hash();
#endif