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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:59:48 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:59:48 +0000 |
commit | 3b9b6d0b8e7f798023c9d109c490449d528fde80 (patch) | |
tree | 2e1c188dd7b8d7475cd163de9ae02c428343669b /lib/dns/dns64.c | |
parent | Initial commit. (diff) | |
download | bind9-3b9b6d0b8e7f798023c9d109c490449d528fde80.tar.xz bind9-3b9b6d0b8e7f798023c9d109c490449d528fde80.zip |
Adding upstream version 1:9.18.19.upstream/1%9.18.19upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'lib/dns/dns64.c')
-rw-r--r-- | lib/dns/dns64.c | 484 |
1 files changed, 484 insertions, 0 deletions
diff --git a/lib/dns/dns64.c b/lib/dns/dns64.c new file mode 100644 index 0000000..b575726 --- /dev/null +++ b/lib/dns/dns64.c @@ -0,0 +1,484 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * SPDX-License-Identifier: MPL-2.0 + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, you can obtain one at https://mozilla.org/MPL/2.0/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +#include <stdbool.h> +#include <string.h> + +#include <isc/list.h> +#include <isc/mem.h> +#include <isc/netaddr.h> +#include <isc/result.h> +#include <isc/string.h> +#include <isc/util.h> + +#include <dns/acl.h> +#include <dns/dns64.h> +#include <dns/rdata.h> +#include <dns/rdataset.h> + +struct dns_dns64 { + unsigned char bits[16]; /* + * Prefix + suffix bits. + */ + dns_acl_t *clients; /* + * Which clients get mapped + * addresses. + */ + dns_acl_t *mapped; /* + * IPv4 addresses to be mapped. + */ + dns_acl_t *excluded; /* + * IPv6 addresses that are + * treated as not existing. + */ + unsigned int prefixlen; /* + * Start of mapped address. + */ + unsigned int flags; + isc_mem_t *mctx; + ISC_LINK(dns_dns64_t) link; +}; + +isc_result_t +dns_dns64_create(isc_mem_t *mctx, const isc_netaddr_t *prefix, + unsigned int prefixlen, const isc_netaddr_t *suffix, + dns_acl_t *clients, dns_acl_t *mapped, dns_acl_t *excluded, + unsigned int flags, dns_dns64_t **dns64p) { + dns_dns64_t *dns64; + unsigned int nbytes = 16; + + REQUIRE(prefix != NULL && prefix->family == AF_INET6); + /* Legal prefix lengths from rfc6052.txt. */ + REQUIRE(prefixlen == 32 || prefixlen == 40 || prefixlen == 48 || + prefixlen == 56 || prefixlen == 64 || prefixlen == 96); + REQUIRE(isc_netaddr_prefixok(prefix, prefixlen) == ISC_R_SUCCESS); + REQUIRE(dns64p != NULL && *dns64p == NULL); + + if (suffix != NULL) { + static const unsigned char zeros[16]; + REQUIRE(prefix->family == AF_INET6); + nbytes = prefixlen / 8 + 4; + /* Bits 64-71 are zeros. rfc6052.txt */ + if (prefixlen >= 32 && prefixlen <= 64) { + nbytes++; + } + REQUIRE(memcmp(suffix->type.in6.s6_addr, zeros, nbytes) == 0); + } + + dns64 = isc_mem_get(mctx, sizeof(dns_dns64_t)); + memset(dns64->bits, 0, sizeof(dns64->bits)); + memmove(dns64->bits, prefix->type.in6.s6_addr, prefixlen / 8); + if (suffix != NULL) { + memmove(dns64->bits + nbytes, suffix->type.in6.s6_addr + nbytes, + 16 - nbytes); + } + dns64->clients = NULL; + if (clients != NULL) { + dns_acl_attach(clients, &dns64->clients); + } + dns64->mapped = NULL; + if (mapped != NULL) { + dns_acl_attach(mapped, &dns64->mapped); + } + dns64->excluded = NULL; + if (excluded != NULL) { + dns_acl_attach(excluded, &dns64->excluded); + } + dns64->prefixlen = prefixlen; + dns64->flags = flags; + ISC_LINK_INIT(dns64, link); + dns64->mctx = NULL; + isc_mem_attach(mctx, &dns64->mctx); + *dns64p = dns64; + return (ISC_R_SUCCESS); +} + +void +dns_dns64_destroy(dns_dns64_t **dns64p) { + dns_dns64_t *dns64; + + REQUIRE(dns64p != NULL && *dns64p != NULL); + + dns64 = *dns64p; + *dns64p = NULL; + + REQUIRE(!ISC_LINK_LINKED(dns64, link)); + + if (dns64->clients != NULL) { + dns_acl_detach(&dns64->clients); + } + if (dns64->mapped != NULL) { + dns_acl_detach(&dns64->mapped); + } + if (dns64->excluded != NULL) { + dns_acl_detach(&dns64->excluded); + } + isc_mem_putanddetach(&dns64->mctx, dns64, sizeof(*dns64)); +} + +isc_result_t +dns_dns64_aaaafroma(const dns_dns64_t *dns64, const isc_netaddr_t *reqaddr, + const dns_name_t *reqsigner, dns_aclenv_t *env, + unsigned int flags, unsigned char *a, unsigned char *aaaa) { + unsigned int nbytes, i; + isc_result_t result; + int match; + + if ((dns64->flags & DNS_DNS64_RECURSIVE_ONLY) != 0 && + (flags & DNS_DNS64_RECURSIVE) == 0) + { + return (DNS_R_DISALLOWED); + } + + if ((dns64->flags & DNS_DNS64_BREAK_DNSSEC) == 0 && + (flags & DNS_DNS64_DNSSEC) != 0) + { + return (DNS_R_DISALLOWED); + } + + if (dns64->clients != NULL) { + result = dns_acl_match(reqaddr, reqsigner, dns64->clients, env, + &match, NULL); + if (result != ISC_R_SUCCESS) { + return (result); + } + if (match <= 0) { + return (DNS_R_DISALLOWED); + } + } + + if (dns64->mapped != NULL) { + struct in_addr ina; + isc_netaddr_t netaddr; + + memmove(&ina.s_addr, a, 4); + isc_netaddr_fromin(&netaddr, &ina); + result = dns_acl_match(&netaddr, NULL, dns64->mapped, env, + &match, NULL); + if (result != ISC_R_SUCCESS) { + return (result); + } + if (match <= 0) { + return (DNS_R_DISALLOWED); + } + } + + nbytes = dns64->prefixlen / 8; + INSIST(nbytes <= 12); + /* Copy prefix. */ + memmove(aaaa, dns64->bits, nbytes); + /* Bits 64-71 are zeros. rfc6052.txt */ + if (nbytes == 8) { + aaaa[nbytes++] = 0; + } + /* Copy mapped address. */ + for (i = 0; i < 4U; i++) { + aaaa[nbytes++] = a[i]; + /* Bits 64-71 are zeros. rfc6052.txt */ + if (nbytes == 8) { + aaaa[nbytes++] = 0; + } + } + /* Copy suffix. */ + memmove(aaaa + nbytes, dns64->bits + nbytes, 16 - nbytes); + return (ISC_R_SUCCESS); +} + +dns_dns64_t * +dns_dns64_next(dns_dns64_t *dns64) { + dns64 = ISC_LIST_NEXT(dns64, link); + return (dns64); +} + +void +dns_dns64_append(dns_dns64list_t *list, dns_dns64_t *dns64) { + ISC_LIST_APPEND(*list, dns64, link); +} + +void +dns_dns64_unlink(dns_dns64list_t *list, dns_dns64_t *dns64) { + ISC_LIST_UNLINK(*list, dns64, link); +} + +bool +dns_dns64_aaaaok(const dns_dns64_t *dns64, const isc_netaddr_t *reqaddr, + const dns_name_t *reqsigner, dns_aclenv_t *env, + unsigned int flags, dns_rdataset_t *rdataset, bool *aaaaok, + size_t aaaaoklen) { + struct in6_addr in6; + isc_netaddr_t netaddr; + isc_result_t result; + int match; + bool answer = false; + bool found = false; + unsigned int i, ok; + + REQUIRE(rdataset != NULL); + REQUIRE(rdataset->type == dns_rdatatype_aaaa); + REQUIRE(rdataset->rdclass == dns_rdataclass_in); + if (aaaaok != NULL) { + REQUIRE(aaaaoklen == dns_rdataset_count(rdataset)); + } + + for (; dns64 != NULL; dns64 = ISC_LIST_NEXT(dns64, link)) { + if ((dns64->flags & DNS_DNS64_RECURSIVE_ONLY) != 0 && + (flags & DNS_DNS64_RECURSIVE) == 0) + { + continue; + } + + if ((dns64->flags & DNS_DNS64_BREAK_DNSSEC) == 0 && + (flags & DNS_DNS64_DNSSEC) != 0) + { + continue; + } + /* + * Work out if this dns64 structure applies to this client. + */ + if (dns64->clients != NULL) { + result = dns_acl_match(reqaddr, reqsigner, + dns64->clients, env, &match, + NULL); + if (result != ISC_R_SUCCESS) { + continue; + } + if (match <= 0) { + continue; + } + } + + if (!found && aaaaok != NULL) { + for (i = 0; i < aaaaoklen; i++) { + aaaaok[i] = false; + } + } + found = true; + + /* + * If we are not excluding any addresses then any AAAA + * will do. + */ + if (dns64->excluded == NULL) { + answer = true; + if (aaaaok == NULL) { + goto done; + } + for (i = 0; i < aaaaoklen; i++) { + aaaaok[i] = true; + } + goto done; + } + + i = 0; + ok = 0; + for (result = dns_rdataset_first(rdataset); + result == ISC_R_SUCCESS; + result = dns_rdataset_next(rdataset)) + { + dns_rdata_t rdata = DNS_RDATA_INIT; + if (aaaaok == NULL || !aaaaok[i]) { + dns_rdataset_current(rdataset, &rdata); + memmove(&in6.s6_addr, rdata.data, 16); + isc_netaddr_fromin6(&netaddr, &in6); + + result = dns_acl_match(&netaddr, NULL, + dns64->excluded, env, + &match, NULL); + if (result == ISC_R_SUCCESS && match <= 0) { + answer = true; + if (aaaaok == NULL) { + goto done; + } + aaaaok[i] = true; + ok++; + } + } else { + ok++; + } + i++; + } + /* + * Are all addresses ok? + */ + if (aaaaok != NULL && ok == aaaaoklen) { + goto done; + } + } + +done: + if (!found && aaaaok != NULL) { + for (i = 0; i < aaaaoklen; i++) { + aaaaok[i] = true; + } + } + return (found ? answer : true); +} + +/* + * Posible mapping of IPV4ONLY.ARPA A records into AAAA records + * for valid RFC6052 prefixes. + */ +static struct { + const unsigned char aa[16]; /* mapped version of 192.0.0.170 */ + const unsigned char ab[16]; /* mapped version of 192.0.0.171 */ + const unsigned char mask[16]; + const unsigned int plen; +} const prefixes[6] = { + { { 0, 0, 0, 0, 192, 0, 0, 170, 0, 0, 0, 0, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 192, 0, 0, 171, 0, 0, 0, 0, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0, 0 }, + 32 }, + { { 0, 0, 0, 0, 0, 192, 0, 0, 0, 170, 0, 0, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 192, 0, 0, 0, 171, 0, 0, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0 }, + 40 }, + { { 0, 0, 0, 0, 0, 0, 192, 0, 0, 0, 170, 0, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 0, 192, 0, 0, 0, 171, 0, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 0, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0 }, + 48 }, + { { 0, 0, 0, 0, 0, 0, 0, 192, 0, 0, 0, 170, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 0, 0, 192, 0, 0, 0, 171, 0, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 0, 0, 255, 255, 255, 255, 255, 0, 0, 0, 0 }, + 56 }, + { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 192, 0, 0, 170, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 0, 192, 0, 0, 171, 0, 0, 0 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, 255, 255, 255, 0, 0, 0 }, + 64 }, + { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 192, 0, 0, 170 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 192, 0, 0, 171 }, + { 0, 0, 0, 0, 0, 0, 0, 0, 255, 0, 0, 0, 255, 255, 255, 255 }, + 96 } +}; + +static unsigned int +search(const dns_rdata_t *rd1, const dns_rdata_t *rd2, unsigned int plen) { + unsigned int i = 0, j; + const unsigned char *c, *m; + + /* + * Resume looking for another aa match? + */ + if (plen != 0U && rd2 == NULL) { + while (i < 6U) { + /* Post increment as we resume on next entry. */ + if (prefixes[i++].plen == plen) { + break; + } + } + } + + for (; i < 6U; i++) { + j = 0; + if (rd2 != NULL) { + /* Find the right entry. */ + if (prefixes[i].plen != plen) { + continue; + } + /* Does the prefix match? */ + while ((j * 8U) < plen) { + if (rd1->data[j] != rd2->data[j]) { + return (0); + } + j++; + } + } + + /* Match well known mapped addresses. */ + c = (rd2 == NULL) ? prefixes[i].aa : prefixes[i].ab; + m = prefixes[i].mask; + for (; j < 16U; j++) { + if ((rd1->data[j] & m[j]) != (c[j] & m[j])) { + break; + } + } + if (j == 16U) { + return (prefixes[i].plen); + } + if (rd2 != NULL) { + return (0); + } + } + return (0); +} + +isc_result_t +dns_dns64_findprefix(dns_rdataset_t *rdataset, isc_netprefix_t *prefix, + size_t *len) { + dns_rdataset_t outer, inner; + unsigned int oplen, iplen; + size_t count = 0; + struct in6_addr ina6; + isc_result_t result; + + REQUIRE(prefix != NULL && len != NULL && *len != 0U); + REQUIRE(rdataset != NULL && rdataset->type == dns_rdatatype_aaaa); + + dns_rdataset_init(&outer); + dns_rdataset_init(&inner); + dns_rdataset_clone(rdataset, &outer); + dns_rdataset_clone(rdataset, &inner); + + for (result = dns_rdataset_first(&outer); result == ISC_R_SUCCESS; + result = dns_rdataset_next(&outer)) + { + dns_rdata_t rd1 = DNS_RDATA_INIT; + dns_rdataset_current(&outer, &rd1); + oplen = 0; + resume: + /* Look for a 192.0.0.170 match. */ + oplen = search(&rd1, NULL, oplen); + if (oplen == 0) { + continue; + } + + /* Look for the 192.0.0.171 match. */ + for (result = dns_rdataset_first(&inner); + result == ISC_R_SUCCESS; + result = dns_rdataset_next(&inner)) + { + dns_rdata_t rd2 = DNS_RDATA_INIT; + + dns_rdataset_current(&inner, &rd2); + iplen = search(&rd2, &rd1, oplen); + if (iplen == 0) { + continue; + } + INSIST(iplen == oplen); + if (count >= *len) { + count++; + break; + } + + /* We have a prefix. */ + memset(ina6.s6_addr, 0, sizeof(ina6.s6_addr)); + memmove(ina6.s6_addr, rd1.data, oplen / 8); + isc_netaddr_fromin6(&prefix[count].addr, &ina6); + prefix[count].prefixlen = oplen; + count++; + break; + } + /* Didn't find a match look for a different prefix length. */ + if (result == ISC_R_NOMORE) { + goto resume; + } + } + if (count == 0U) { + return (ISC_R_NOTFOUND); + } + if (count > *len) { + *len = count; + return (ISC_R_NOSPACE); + } + *len = count; + return (ISC_R_SUCCESS); +} |