| /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
| |
| /*** |
| This file is part of systemd. |
| |
| Copyright 2014 Lennart Poettering |
| |
| systemd is free software; you can redistribute it and/or modify it |
| under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or |
| (at your option) any later version. |
| |
| systemd is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include "utf8.h" |
| #include "util.h" |
| #include "strv.h" |
| #include "resolved-dns-domain.h" |
| #include "resolved-dns-packet.h" |
| |
| int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) { |
| DnsPacket *p; |
| size_t a; |
| |
| assert(ret); |
| |
| if (mtu <= 0) |
| a = DNS_PACKET_SIZE_START; |
| else |
| a = mtu; |
| |
| if (a < DNS_PACKET_HEADER_SIZE) |
| a = DNS_PACKET_HEADER_SIZE; |
| |
| /* round up to next page size */ |
| a = PAGE_ALIGN(ALIGN(sizeof(DnsPacket)) + a) - ALIGN(sizeof(DnsPacket)); |
| |
| /* make sure we never allocate more than useful */ |
| if (a > DNS_PACKET_SIZE_MAX) |
| a = DNS_PACKET_SIZE_MAX; |
| |
| p = malloc0(ALIGN(sizeof(DnsPacket)) + a); |
| if (!p) |
| return -ENOMEM; |
| |
| p->size = p->rindex = DNS_PACKET_HEADER_SIZE; |
| p->allocated = a; |
| p->protocol = protocol; |
| p->n_ref = 1; |
| |
| *ret = p; |
| |
| return 0; |
| } |
| |
| int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu) { |
| DnsPacket *p; |
| DnsPacketHeader *h; |
| int r; |
| |
| assert(ret); |
| |
| r = dns_packet_new(&p, protocol, mtu); |
| if (r < 0) |
| return r; |
| |
| h = DNS_PACKET_HEADER(p); |
| |
| if (protocol == DNS_PROTOCOL_LLMNR) |
| h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */, |
| 0 /* opcode */, |
| 0 /* c */, |
| 0 /* tc */, |
| 0 /* t */, |
| 0 /* ra */, |
| 0 /* ad */, |
| 0 /* cd */, |
| 0 /* rcode */)); |
| else |
| h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */, |
| 0 /* opcode */, |
| 0 /* aa */, |
| 0 /* tc */, |
| 1 /* rd (ask for recursion) */, |
| 0 /* ra */, |
| 0 /* ad */, |
| 0 /* cd */, |
| 0 /* rcode */)); |
| |
| *ret = p; |
| return 0; |
| } |
| |
| DnsPacket *dns_packet_ref(DnsPacket *p) { |
| |
| if (!p) |
| return NULL; |
| |
| assert(p->n_ref > 0); |
| p->n_ref++; |
| return p; |
| } |
| |
| static void dns_packet_free(DnsPacket *p) { |
| char *s; |
| |
| assert(p); |
| |
| dns_question_unref(p->question); |
| dns_answer_unref(p->answer); |
| |
| while ((s = hashmap_steal_first_key(p->names))) |
| free(s); |
| hashmap_free(p->names); |
| |
| free(p->_data); |
| free(p); |
| } |
| |
| DnsPacket *dns_packet_unref(DnsPacket *p) { |
| if (!p) |
| return NULL; |
| |
| assert(p->n_ref > 0); |
| |
| if (p->n_ref == 1) |
| dns_packet_free(p); |
| else |
| p->n_ref--; |
| |
| return NULL; |
| } |
| |
| int dns_packet_validate(DnsPacket *p) { |
| assert(p); |
| |
| if (p->size < DNS_PACKET_HEADER_SIZE) |
| return -EBADMSG; |
| |
| if (p->size > DNS_PACKET_SIZE_MAX) |
| return -EBADMSG; |
| |
| return 1; |
| } |
| |
| int dns_packet_validate_reply(DnsPacket *p) { |
| int r; |
| |
| assert(p); |
| |
| r = dns_packet_validate(p); |
| if (r < 0) |
| return r; |
| |
| if (DNS_PACKET_QR(p) != 1) |
| return 0; |
| |
| if (DNS_PACKET_OPCODE(p) != 0) |
| return -EBADMSG; |
| |
| /* RFC 4795, Section 2.1.1. says to discard all replies with QDCOUNT != 1 */ |
| if (p->protocol == DNS_PROTOCOL_LLMNR && |
| DNS_PACKET_QDCOUNT(p) != 1) |
| return -EBADMSG; |
| |
| return 1; |
| } |
| |
| int dns_packet_validate_query(DnsPacket *p) { |
| int r; |
| |
| assert(p); |
| |
| r = dns_packet_validate(p); |
| if (r < 0) |
| return r; |
| |
| if (DNS_PACKET_QR(p) != 0) |
| return 0; |
| |
| if (DNS_PACKET_OPCODE(p) != 0) |
| return -EBADMSG; |
| |
| if (DNS_PACKET_TC(p)) |
| return -EBADMSG; |
| |
| /* RFC 4795, Section 2.1.1. says to discard all queries with QDCOUNT != 1 */ |
| if (p->protocol == DNS_PROTOCOL_LLMNR && |
| DNS_PACKET_QDCOUNT(p) != 1) |
| return -EBADMSG; |
| |
| /* RFC 4795, Section 2.1.1. says to discard all queries with ANCOUNT != 0 */ |
| if (DNS_PACKET_ANCOUNT(p) > 0) |
| return -EBADMSG; |
| |
| /* RFC 4795, Section 2.1.1. says to discard all queries with NSCOUNT != 0 */ |
| if (DNS_PACKET_NSCOUNT(p) > 0) |
| return -EBADMSG; |
| |
| return 1; |
| } |
| |
| static int dns_packet_extend(DnsPacket *p, size_t add, void **ret, size_t *start) { |
| assert(p); |
| |
| if (p->size + add > p->allocated) { |
| size_t a; |
| |
| a = PAGE_ALIGN((p->size + add) * 2); |
| if (a > DNS_PACKET_SIZE_MAX) |
| a = DNS_PACKET_SIZE_MAX; |
| |
| if (p->size + add > a) |
| return -EMSGSIZE; |
| |
| if (p->_data) { |
| void *d; |
| |
| d = realloc(p->_data, a); |
| if (!d) |
| return -ENOMEM; |
| |
| p->_data = d; |
| } else { |
| p->_data = malloc(a); |
| if (!p->_data) |
| return -ENOMEM; |
| |
| memcpy(p->_data, (uint8_t*) p + ALIGN(sizeof(DnsPacket)), p->size); |
| memzero((uint8_t*) p->_data + p->size, a - p->size); |
| } |
| |
| p->allocated = a; |
| } |
| |
| if (start) |
| *start = p->size; |
| |
| if (ret) |
| *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->size; |
| |
| p->size += add; |
| return 0; |
| } |
| |
| static void dns_packet_truncate(DnsPacket *p, size_t sz) { |
| Iterator i; |
| char *s; |
| void *n; |
| |
| assert(p); |
| |
| if (p->size <= sz) |
| return; |
| |
| HASHMAP_FOREACH_KEY(s, n, p->names, i) { |
| |
| if (PTR_TO_SIZE(n) < sz) |
| continue; |
| |
| hashmap_remove(p->names, s); |
| free(s); |
| } |
| |
| p->size = sz; |
| } |
| |
| int dns_packet_append_blob(DnsPacket *p, const void *d, size_t l, size_t *start) { |
| void *q; |
| int r; |
| |
| assert(p); |
| |
| r = dns_packet_extend(p, l, &q, start); |
| if (r < 0) |
| return r; |
| |
| memcpy(q, d, l); |
| return 0; |
| } |
| |
| int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start) { |
| void *d; |
| int r; |
| |
| assert(p); |
| |
| r = dns_packet_extend(p, sizeof(uint8_t), &d, start); |
| if (r < 0) |
| return r; |
| |
| ((uint8_t*) d)[0] = v; |
| |
| return 0; |
| } |
| |
| int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start) { |
| void *d; |
| int r; |
| |
| assert(p); |
| |
| r = dns_packet_extend(p, sizeof(uint16_t), &d, start); |
| if (r < 0) |
| return r; |
| |
| ((uint8_t*) d)[0] = (uint8_t) (v >> 8); |
| ((uint8_t*) d)[1] = (uint8_t) v; |
| |
| return 0; |
| } |
| |
| int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start) { |
| void *d; |
| int r; |
| |
| assert(p); |
| |
| r = dns_packet_extend(p, sizeof(uint32_t), &d, start); |
| if (r < 0) |
| return r; |
| |
| ((uint8_t*) d)[0] = (uint8_t) (v >> 24); |
| ((uint8_t*) d)[1] = (uint8_t) (v >> 16); |
| ((uint8_t*) d)[2] = (uint8_t) (v >> 8); |
| ((uint8_t*) d)[3] = (uint8_t) v; |
| |
| return 0; |
| } |
| |
| int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start) { |
| void *d; |
| size_t l; |
| int r; |
| |
| assert(p); |
| assert(s); |
| |
| l = strlen(s); |
| if (l > 255) |
| return -E2BIG; |
| |
| r = dns_packet_extend(p, 1 + l, &d, start); |
| if (r < 0) |
| return r; |
| |
| ((uint8_t*) d)[0] = (uint8_t) l; |
| memcpy(((uint8_t*) d) + 1, s, l); |
| |
| return 0; |
| } |
| |
| int dns_packet_append_label(DnsPacket *p, const char *d, size_t l, size_t *start) { |
| void *w; |
| int r; |
| |
| assert(p); |
| assert(d); |
| |
| if (l > DNS_LABEL_MAX) |
| return -E2BIG; |
| |
| r = dns_packet_extend(p, 1 + l, &w, start); |
| if (r < 0) |
| return r; |
| |
| ((uint8_t*) w)[0] = (uint8_t) l; |
| memcpy(((uint8_t*) w) + 1, d, l); |
| |
| return 0; |
| } |
| |
| int dns_packet_append_name(DnsPacket *p, const char *name, |
| bool allow_compression, size_t *start) { |
| size_t saved_size; |
| int r; |
| |
| assert(p); |
| assert(name); |
| |
| saved_size = p->size; |
| |
| while (*name) { |
| _cleanup_free_ char *s = NULL; |
| char label[DNS_LABEL_MAX]; |
| size_t n = 0; |
| int k; |
| |
| if (allow_compression) |
| n = PTR_TO_SIZE(hashmap_get(p->names, name)); |
| if (n > 0) { |
| assert(n < p->size); |
| |
| if (n < 0x4000) { |
| r = dns_packet_append_uint16(p, 0xC000 | n, NULL); |
| if (r < 0) |
| goto fail; |
| |
| goto done; |
| } |
| } |
| |
| s = strdup(name); |
| if (!s) { |
| r = -ENOMEM; |
| goto fail; |
| } |
| |
| r = dns_label_unescape(&name, label, sizeof(label)); |
| if (r < 0) |
| goto fail; |
| |
| if (p->protocol == DNS_PROTOCOL_DNS) |
| k = dns_label_apply_idna(label, r, label, sizeof(label)); |
| else |
| k = dns_label_undo_idna(label, r, label, sizeof(label)); |
| if (k < 0) { |
| r = k; |
| goto fail; |
| } |
| if (k > 0) |
| r = k; |
| |
| r = dns_packet_append_label(p, label, r, &n); |
| if (r < 0) |
| goto fail; |
| |
| if (allow_compression) { |
| r = hashmap_ensure_allocated(&p->names, &dns_name_hash_ops); |
| if (r < 0) |
| goto fail; |
| |
| r = hashmap_put(p->names, s, SIZE_TO_PTR(n)); |
| if (r < 0) |
| goto fail; |
| |
| s = NULL; |
| } |
| } |
| |
| r = dns_packet_append_uint8(p, 0, NULL); |
| if (r < 0) |
| return r; |
| |
| done: |
| if (start) |
| *start = saved_size; |
| |
| return 0; |
| |
| fail: |
| dns_packet_truncate(p, saved_size); |
| return r; |
| } |
| |
| int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start) { |
| size_t saved_size; |
| int r; |
| |
| assert(p); |
| assert(k); |
| |
| saved_size = p->size; |
| |
| r = dns_packet_append_name(p, DNS_RESOURCE_KEY_NAME(k), true, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint16(p, k->type, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint16(p, k->class, NULL); |
| if (r < 0) |
| goto fail; |
| |
| if (start) |
| *start = saved_size; |
| |
| return 0; |
| |
| fail: |
| dns_packet_truncate(p, saved_size); |
| return r; |
| } |
| |
| int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start) { |
| size_t saved_size, rdlength_offset, end, rdlength; |
| int r; |
| |
| assert(p); |
| assert(rr); |
| |
| saved_size = p->size; |
| |
| r = dns_packet_append_key(p, rr->key, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->ttl, NULL); |
| if (r < 0) |
| goto fail; |
| |
| /* Initially we write 0 here */ |
| r = dns_packet_append_uint16(p, 0, &rdlength_offset); |
| if (r < 0) |
| goto fail; |
| |
| switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) { |
| |
| case DNS_TYPE_SRV: |
| r = dns_packet_append_uint16(p, rr->srv.priority, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint16(p, rr->srv.weight, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint16(p, rr->srv.port, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_name(p, rr->srv.name, 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, NULL); |
| break; |
| |
| case DNS_TYPE_HINFO: |
| r = dns_packet_append_string(p, rr->hinfo.cpu, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_string(p, rr->hinfo.os, NULL); |
| break; |
| |
| case DNS_TYPE_SPF: /* exactly the same as TXT */ |
| case DNS_TYPE_TXT: { |
| char **s; |
| |
| STRV_FOREACH(s, rr->txt.strings) { |
| r = dns_packet_append_string(p, *s, NULL); |
| if (r < 0) |
| goto fail; |
| } |
| |
| r = 0; |
| break; |
| } |
| |
| case DNS_TYPE_A: |
| r = dns_packet_append_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL); |
| break; |
| |
| case DNS_TYPE_AAAA: |
| r = dns_packet_append_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL); |
| break; |
| |
| case DNS_TYPE_SOA: |
| r = dns_packet_append_name(p, rr->soa.mname, true, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_name(p, rr->soa.rname, true, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->soa.serial, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->soa.refresh, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->soa.retry, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->soa.expire, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->soa.minimum, NULL); |
| break; |
| |
| case DNS_TYPE_MX: |
| r = dns_packet_append_uint16(p, rr->mx.priority, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_name(p, rr->mx.exchange, true, NULL); |
| break; |
| |
| case DNS_TYPE_LOC: |
| r = dns_packet_append_uint8(p, rr->loc.version, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint8(p, rr->loc.size, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint8(p, rr->loc.horiz_pre, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint8(p, rr->loc.vert_pre, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->loc.latitude, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->loc.longitude, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->loc.altitude, NULL); |
| break; |
| |
| case DNS_TYPE_SSHFP: |
| r = dns_packet_append_uint8(p, rr->sshfp.algorithm, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint8(p, rr->sshfp.fptype, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_blob(p, rr->sshfp.key, rr->sshfp.key_size, NULL); |
| break; |
| |
| case DNS_TYPE_DNSKEY: |
| r = dns_packet_append_uint16(p, dnskey_to_flags(rr), NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint8(p, 3u, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint8(p, rr->dnskey.algorithm, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_blob(p, rr->dnskey.key, rr->dnskey.key_size, NULL); |
| break; |
| |
| case DNS_TYPE_RRSIG: |
| r = dns_packet_append_uint16(p, rr->rrsig.type_covered, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint8(p, rr->rrsig.algorithm, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint8(p, rr->rrsig.labels, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->rrsig.original_ttl, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->rrsig.expiration, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint32(p, rr->rrsig.inception, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_uint8(p, rr->rrsig.key_tag, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_name(p, rr->rrsig.signer, false, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_append_blob(p, rr->rrsig.signature, rr->rrsig.signature_size, NULL); |
| break; |
| |
| case _DNS_TYPE_INVALID: /* unparseable */ |
| default: |
| |
| r = dns_packet_append_blob(p, rr->generic.data, rr->generic.size, NULL); |
| break; |
| } |
| if (r < 0) |
| goto fail; |
| |
| /* Let's calculate the actual data size and update the field */ |
| rdlength = p->size - rdlength_offset - sizeof(uint16_t); |
| if (rdlength > 0xFFFF) { |
| r = ENOSPC; |
| goto fail; |
| } |
| |
| end = p->size; |
| p->size = rdlength_offset; |
| r = dns_packet_append_uint16(p, rdlength, NULL); |
| if (r < 0) |
| goto fail; |
| p->size = end; |
| |
| if (start) |
| *start = saved_size; |
| |
| return 0; |
| |
| fail: |
| dns_packet_truncate(p, saved_size); |
| return r; |
| } |
| |
| |
| int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) { |
| assert(p); |
| |
| if (p->rindex + sz > p->size) |
| return -EMSGSIZE; |
| |
| if (ret) |
| *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->rindex; |
| |
| if (start) |
| *start = p->rindex; |
| |
| p->rindex += sz; |
| return 0; |
| } |
| |
| void dns_packet_rewind(DnsPacket *p, size_t idx) { |
| assert(p); |
| assert(idx <= p->size); |
| assert(idx >= DNS_PACKET_HEADER_SIZE); |
| |
| p->rindex = idx; |
| } |
| |
| int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start) { |
| const void *q; |
| int r; |
| |
| assert(p); |
| assert(d); |
| |
| r = dns_packet_read(p, sz, &q, start); |
| if (r < 0) |
| return r; |
| |
| memcpy(d, q, sz); |
| return 0; |
| } |
| |
| int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start) { |
| const void *d; |
| int r; |
| |
| assert(p); |
| |
| r = dns_packet_read(p, sizeof(uint8_t), &d, start); |
| if (r < 0) |
| return r; |
| |
| *ret = ((uint8_t*) d)[0]; |
| return 0; |
| } |
| |
| int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start) { |
| const void *d; |
| int r; |
| |
| assert(p); |
| |
| r = dns_packet_read(p, sizeof(uint16_t), &d, start); |
| if (r < 0) |
| return r; |
| |
| *ret = (((uint16_t) ((uint8_t*) d)[0]) << 8) | |
| ((uint16_t) ((uint8_t*) d)[1]); |
| return 0; |
| } |
| |
| int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start) { |
| const void *d; |
| int r; |
| |
| assert(p); |
| |
| r = dns_packet_read(p, sizeof(uint32_t), &d, start); |
| if (r < 0) |
| return r; |
| |
| *ret = (((uint32_t) ((uint8_t*) d)[0]) << 24) | |
| (((uint32_t) ((uint8_t*) d)[1]) << 16) | |
| (((uint32_t) ((uint8_t*) d)[2]) << 8) | |
| ((uint32_t) ((uint8_t*) d)[3]); |
| |
| return 0; |
| } |
| |
| int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) { |
| size_t saved_rindex; |
| const void *d; |
| char *t; |
| uint8_t c; |
| int r; |
| |
| assert(p); |
| |
| saved_rindex = p->rindex; |
| |
| r = dns_packet_read_uint8(p, &c, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read(p, c, &d, NULL); |
| if (r < 0) |
| goto fail; |
| |
| if (memchr(d, 0, c)) { |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| t = strndup(d, c); |
| if (!t) { |
| r = -ENOMEM; |
| goto fail; |
| } |
| |
| if (!utf8_is_valid(t)) { |
| free(t); |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| *ret = t; |
| |
| if (start) |
| *start = saved_rindex; |
| |
| return 0; |
| |
| fail: |
| dns_packet_rewind(p, saved_rindex); |
| return r; |
| } |
| |
| int dns_packet_read_name(DnsPacket *p, char **_ret, |
| bool allow_compression, size_t *start) { |
| size_t saved_rindex, after_rindex = 0; |
| _cleanup_free_ char *ret = NULL; |
| size_t n = 0, allocated = 0; |
| bool first = true; |
| int r; |
| |
| assert(p); |
| assert(_ret); |
| |
| saved_rindex = p->rindex; |
| |
| for (;;) { |
| uint8_t c, d; |
| |
| r = dns_packet_read_uint8(p, &c, NULL); |
| if (r < 0) |
| goto fail; |
| |
| if (c == 0) |
| /* End of name */ |
| break; |
| else if (c <= 63) { |
| _cleanup_free_ char *t = NULL; |
| const char *label; |
| |
| /* Literal label */ |
| r = dns_packet_read(p, c, (const void**) &label, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_label_escape(label, c, &t); |
| if (r < 0) |
| goto fail; |
| |
| if (!GREEDY_REALLOC(ret, allocated, n + !first + strlen(t) + 1)) { |
| r = -ENOMEM; |
| goto fail; |
| } |
| |
| if (!first) |
| ret[n++] = '.'; |
| else |
| first = false; |
| |
| memcpy(ret + n, t, r); |
| n += r; |
| continue; |
| } else if (allow_compression && (c & 0xc0) == 0xc0) { |
| uint16_t ptr; |
| |
| /* Pointer */ |
| r = dns_packet_read_uint8(p, &d, NULL); |
| if (r < 0) |
| goto fail; |
| |
| ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d; |
| if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= saved_rindex) { |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| if (after_rindex == 0) |
| after_rindex = p->rindex; |
| |
| p->rindex = ptr; |
| } else |
| goto fail; |
| } |
| |
| if (!GREEDY_REALLOC(ret, allocated, n + 1)) { |
| r = -ENOMEM; |
| goto fail; |
| } |
| |
| ret[n] = 0; |
| |
| if (after_rindex != 0) |
| p->rindex= after_rindex; |
| |
| *_ret = ret; |
| ret = NULL; |
| |
| if (start) |
| *start = saved_rindex; |
| |
| return 0; |
| |
| fail: |
| dns_packet_rewind(p, saved_rindex); |
| return r; |
| } |
| |
| int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, size_t *start) { |
| _cleanup_free_ char *name = NULL; |
| uint16_t class, type; |
| DnsResourceKey *key; |
| size_t saved_rindex; |
| int r; |
| |
| assert(p); |
| assert(ret); |
| |
| saved_rindex = p->rindex; |
| |
| r = dns_packet_read_name(p, &name, true, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint16(p, &type, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint16(p, &class, NULL); |
| if (r < 0) |
| goto fail; |
| |
| key = dns_resource_key_new_consume(class, type, name); |
| if (!key) { |
| r = -ENOMEM; |
| goto fail; |
| } |
| |
| name = NULL; |
| *ret = key; |
| |
| if (start) |
| *start = saved_rindex; |
| |
| return 0; |
| fail: |
| dns_packet_rewind(p, saved_rindex); |
| return r; |
| } |
| |
| static int dns_packet_read_public_key(DnsPacket *p, size_t length, |
| void **dp, size_t *lengthp, |
| size_t *start) { |
| int r; |
| const void *d; |
| void *d2; |
| |
| r = dns_packet_read(p, length, &d, NULL); |
| if (r < 0) |
| return r; |
| |
| d2 = memdup(d, length); |
| if (!d2) |
| return -ENOMEM; |
| |
| *dp = d2; |
| *lengthp = length; |
| return 0; |
| } |
| |
| static bool loc_size_ok(uint8_t size) { |
| uint8_t m = size >> 4, e = size & 0xF; |
| |
| return m <= 9 && e <= 9 && (m > 0 || e == 0); |
| } |
| |
| static int dnskey_parse_flags(DnsResourceRecord *rr, uint16_t flags) { |
| assert(rr); |
| |
| if (flags & ~(DNSKEY_FLAG_SEP | DNSKEY_FLAG_ZONE_KEY)) |
| return -EBADMSG; |
| |
| rr->dnskey.zone_key_flag = flags & DNSKEY_FLAG_ZONE_KEY; |
| rr->dnskey.sep_flag = flags & DNSKEY_FLAG_SEP; |
| return 0; |
| } |
| |
| int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) { |
| _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; |
| _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; |
| size_t saved_rindex, offset; |
| uint16_t rdlength; |
| const void *d; |
| int r; |
| |
| assert(p); |
| assert(ret); |
| |
| saved_rindex = p->rindex; |
| |
| r = dns_packet_read_key(p, &key, NULL); |
| if (r < 0) |
| goto fail; |
| |
| if (key->class == DNS_CLASS_ANY || |
| key->type == DNS_TYPE_ANY) { |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| rr = dns_resource_record_new(key); |
| if (!rr) { |
| r = -ENOMEM; |
| goto fail; |
| } |
| |
| r = dns_packet_read_uint32(p, &rr->ttl, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint16(p, &rdlength, NULL); |
| if (r < 0) |
| goto fail; |
| |
| if (p->rindex + rdlength > p->size) { |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| offset = p->rindex; |
| |
| switch (rr->key->type) { |
| |
| case DNS_TYPE_SRV: |
| r = dns_packet_read_uint16(p, &rr->srv.priority, NULL); |
| if (r < 0) |
| goto fail; |
| r = dns_packet_read_uint16(p, &rr->srv.weight, NULL); |
| if (r < 0) |
| goto fail; |
| r = dns_packet_read_uint16(p, &rr->srv.port, NULL); |
| if (r < 0) |
| goto fail; |
| r = dns_packet_read_name(p, &rr->srv.name, true, NULL); |
| break; |
| |
| case DNS_TYPE_PTR: |
| case DNS_TYPE_NS: |
| case DNS_TYPE_CNAME: |
| case DNS_TYPE_DNAME: |
| r = dns_packet_read_name(p, &rr->ptr.name, true, NULL); |
| break; |
| |
| case DNS_TYPE_HINFO: |
| r = dns_packet_read_string(p, &rr->hinfo.cpu, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_string(p, &rr->hinfo.os, NULL); |
| break; |
| |
| case DNS_TYPE_SPF: /* exactly the same as TXT */ |
| case DNS_TYPE_TXT: { |
| char *s; |
| |
| while (p->rindex < offset + rdlength) { |
| r = dns_packet_read_string(p, &s, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = strv_consume(&rr->txt.strings, s); |
| if (r < 0) |
| goto fail; |
| } |
| |
| r = 0; |
| break; |
| } |
| |
| case DNS_TYPE_A: |
| r = dns_packet_read_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL); |
| break; |
| |
| case DNS_TYPE_AAAA: |
| r = dns_packet_read_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL); |
| break; |
| |
| case DNS_TYPE_SOA: |
| r = dns_packet_read_name(p, &rr->soa.mname, true, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_name(p, &rr->soa.rname, true, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->soa.serial, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->soa.refresh, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->soa.retry, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->soa.expire, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->soa.minimum, NULL); |
| break; |
| |
| case DNS_TYPE_MX: |
| r = dns_packet_read_uint16(p, &rr->mx.priority, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_name(p, &rr->mx.exchange, true, NULL); |
| break; |
| |
| case DNS_TYPE_LOC: { |
| uint8_t t; |
| size_t pos; |
| |
| r = dns_packet_read_uint8(p, &t, &pos); |
| if (r < 0) |
| goto fail; |
| |
| if (t == 0) { |
| rr->loc.version = t; |
| |
| r = dns_packet_read_uint8(p, &rr->loc.size, NULL); |
| if (r < 0) |
| goto fail; |
| |
| if (!loc_size_ok(rr->loc.size)) { |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| r = dns_packet_read_uint8(p, &rr->loc.horiz_pre, NULL); |
| if (r < 0) |
| goto fail; |
| |
| if (!loc_size_ok(rr->loc.horiz_pre)) { |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| r = dns_packet_read_uint8(p, &rr->loc.vert_pre, NULL); |
| if (r < 0) |
| goto fail; |
| |
| if (!loc_size_ok(rr->loc.vert_pre)) { |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| r = dns_packet_read_uint32(p, &rr->loc.latitude, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->loc.longitude, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->loc.altitude, NULL); |
| if (r < 0) |
| goto fail; |
| |
| break; |
| } else { |
| dns_packet_rewind(p, pos); |
| rr->unparseable = true; |
| goto unparseable; |
| } |
| } |
| |
| case DNS_TYPE_SSHFP: |
| r = dns_packet_read_uint8(p, &rr->sshfp.algorithm, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint8(p, &rr->sshfp.fptype, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_public_key(p, rdlength - 2, |
| &rr->sshfp.key, &rr->sshfp.key_size, |
| NULL); |
| break; |
| |
| case DNS_TYPE_DNSKEY: { |
| uint16_t flags; |
| uint8_t proto; |
| |
| r = dns_packet_read_uint16(p, &flags, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dnskey_parse_flags(rr, flags); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint8(p, &proto, NULL); |
| if (r < 0) |
| goto fail; |
| |
| /* protocol is required to be always 3 */ |
| if (proto != 3) { |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| r = dns_packet_read_uint8(p, &rr->dnskey.algorithm, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_public_key(p, rdlength - 4, |
| &rr->dnskey.key, &rr->dnskey.key_size, |
| NULL); |
| break; |
| } |
| |
| case DNS_TYPE_RRSIG: |
| r = dns_packet_read_uint16(p, &rr->rrsig.type_covered, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint8(p, &rr->rrsig.algorithm, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint8(p, &rr->rrsig.labels, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->rrsig.original_ttl, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->rrsig.expiration, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint32(p, &rr->rrsig.inception, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_uint16(p, &rr->rrsig.key_tag, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_name(p, &rr->rrsig.signer, false, NULL); |
| if (r < 0) |
| goto fail; |
| |
| r = dns_packet_read_public_key(p, offset + rdlength - p->rindex, |
| &rr->rrsig.signature, &rr->rrsig.signature_size, |
| NULL); |
| break; |
| |
| default: |
| unparseable: |
| r = dns_packet_read(p, rdlength, &d, NULL); |
| if (r < 0) |
| goto fail; |
| |
| rr->generic.data = memdup(d, rdlength); |
| if (!rr->generic.data) { |
| r = -ENOMEM; |
| goto fail; |
| } |
| |
| rr->generic.size = rdlength; |
| break; |
| } |
| if (r < 0) |
| goto fail; |
| if (p->rindex != offset + rdlength) { |
| r = -EBADMSG; |
| goto fail; |
| } |
| |
| *ret = rr; |
| rr = NULL; |
| |
| if (start) |
| *start = saved_rindex; |
| |
| return 0; |
| fail: |
| dns_packet_rewind(p, saved_rindex); |
| return r; |
| } |
| |
| int dns_packet_extract(DnsPacket *p) { |
| _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL; |
| _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; |
| size_t saved_rindex; |
| unsigned n, i; |
| int r; |
| |
| if (p->extracted) |
| return 0; |
| |
| saved_rindex = p->rindex; |
| dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE); |
| |
| n = DNS_PACKET_QDCOUNT(p); |
| if (n > 0) { |
| question = dns_question_new(n); |
| if (!question) { |
| r = -ENOMEM; |
| goto finish; |
| } |
| |
| for (i = 0; i < n; i++) { |
| _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; |
| |
| r = dns_packet_read_key(p, &key, NULL); |
| if (r < 0) |
| goto finish; |
| |
| r = dns_question_add(question, key); |
| if (r < 0) |
| goto finish; |
| } |
| } |
| |
| n = DNS_PACKET_RRCOUNT(p); |
| if (n > 0) { |
| answer = dns_answer_new(n); |
| if (!answer) { |
| r = -ENOMEM; |
| goto finish; |
| } |
| |
| for (i = 0; i < n; i++) { |
| _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; |
| |
| r = dns_packet_read_rr(p, &rr, NULL); |
| if (r < 0) |
| goto finish; |
| |
| r = dns_answer_add(answer, rr); |
| if (r < 0) |
| goto finish; |
| } |
| } |
| |
| p->question = question; |
| question = NULL; |
| |
| p->answer = answer; |
| answer = NULL; |
| |
| p->extracted = true; |
| |
| r = 0; |
| |
| finish: |
| p->rindex = saved_rindex; |
| return r; |
| } |
| |
| static const char* const dns_rcode_table[_DNS_RCODE_MAX_DEFINED] = { |
| [DNS_RCODE_SUCCESS] = "SUCCESS", |
| [DNS_RCODE_FORMERR] = "FORMERR", |
| [DNS_RCODE_SERVFAIL] = "SERVFAIL", |
| [DNS_RCODE_NXDOMAIN] = "NXDOMAIN", |
| [DNS_RCODE_NOTIMP] = "NOTIMP", |
| [DNS_RCODE_REFUSED] = "REFUSED", |
| [DNS_RCODE_YXDOMAIN] = "YXDOMAIN", |
| [DNS_RCODE_YXRRSET] = "YRRSET", |
| [DNS_RCODE_NXRRSET] = "NXRRSET", |
| [DNS_RCODE_NOTAUTH] = "NOTAUTH", |
| [DNS_RCODE_NOTZONE] = "NOTZONE", |
| [DNS_RCODE_BADVERS] = "BADVERS", |
| [DNS_RCODE_BADKEY] = "BADKEY", |
| [DNS_RCODE_BADTIME] = "BADTIME", |
| [DNS_RCODE_BADMODE] = "BADMODE", |
| [DNS_RCODE_BADNAME] = "BADNAME", |
| [DNS_RCODE_BADALG] = "BADALG", |
| [DNS_RCODE_BADTRUNC] = "BADTRUNC", |
| }; |
| DEFINE_STRING_TABLE_LOOKUP(dns_rcode, int); |
| |
| static const char* const dns_protocol_table[_DNS_PROTOCOL_MAX] = { |
| [DNS_PROTOCOL_DNS] = "dns", |
| [DNS_PROTOCOL_MDNS] = "mdns", |
| [DNS_PROTOCOL_LLMNR] = "llmnr", |
| }; |
| DEFINE_STRING_TABLE_LOOKUP(dns_protocol, DnsProtocol); |
| |
| static const char* const dnssec_algorithm_table[_DNSSEC_ALGORITHM_MAX_DEFINED] = { |
| [DNSSEC_ALGORITHM_RSAMD5] = "RSAMD5", |
| [DNSSEC_ALGORITHM_DH] = "DH", |
| [DNSSEC_ALGORITHM_DSA] = "DSA", |
| [DNSSEC_ALGORITHM_ECC] = "ECC", |
| [DNSSEC_ALGORITHM_RSASHA1] = "RSASHA1", |
| [DNSSEC_ALGORITHM_INDIRECT] = "INDIRECT", |
| [DNSSEC_ALGORITHM_PRIVATEDNS] = "PRIVATEDNS", |
| [DNSSEC_ALGORITHM_PRIVATEOID] = "PRIVATEOID", |
| }; |
| DEFINE_STRING_TABLE_LOOKUP(dnssec_algorithm, int); |