summaryrefslogtreecommitdiff
path: root/src/resolve/resolved-dns-packet.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/resolve/resolved-dns-packet.c')
-rw-r--r--src/resolve/resolved-dns-packet.c2301
1 files changed, 0 insertions, 2301 deletions
diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
deleted file mode 100644
index 337a8c473f..0000000000
--- a/src/resolve/resolved-dns-packet.c
+++ /dev/null
@@ -1,2301 +0,0 @@
-/***
- 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 "alloc-util.h"
-#include "dns-domain.h"
-#include "resolved-dns-packet.h"
-#include "string-table.h"
-#include "strv.h"
-#include "unaligned.h"
-#include "utf8.h"
-#include "util.h"
-
-#define EDNS0_OPT_DO (1<<15)
-
-typedef struct DnsPacketRewinder {
- DnsPacket *packet;
- size_t saved_rindex;
-} DnsPacketRewinder;
-
-static void rewind_dns_packet(DnsPacketRewinder *rewinder) {
- if (rewinder->packet)
- dns_packet_rewind(rewinder->packet, rewinder->saved_rindex);
-}
-
-#define INIT_REWINDER(rewinder, p) do { rewinder.packet = p; rewinder.saved_rindex = p->rindex; } while (0)
-#define CANCEL_REWINDER(rewinder) do { rewinder.packet = NULL; } while (0)
-
-int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) {
- DnsPacket *p;
- size_t a;
-
- assert(ret);
-
- if (mtu <= UDP_PACKET_HEADER_SIZE)
- a = DNS_PACKET_SIZE_START;
- else
- a = mtu - UDP_PACKET_HEADER_SIZE;
-
- 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->opt_start = p->opt_size = (size_t) -1;
- p->n_ref = 1;
-
- *ret = p;
-
- return 0;
-}
-
-void dns_packet_set_flags(DnsPacket *p, bool dnssec_checking_disabled, bool truncated) {
-
- DnsPacketHeader *h;
-
- assert(p);
-
- h = DNS_PACKET_HEADER(p);
-
- switch(p->protocol) {
- case DNS_PROTOCOL_LLMNR:
- assert(!truncated);
-
- 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 */));
- break;
-
- case DNS_PROTOCOL_MDNS:
- h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
- 0 /* opcode */,
- 0 /* aa */,
- truncated /* tc */,
- 0 /* rd (ask for recursion) */,
- 0 /* ra */,
- 0 /* ad */,
- 0 /* cd */,
- 0 /* rcode */));
- break;
-
- default:
- assert(!truncated);
-
- h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
- 0 /* opcode */,
- 0 /* aa */,
- 0 /* tc */,
- 1 /* rd (ask for recursion) */,
- 0 /* ra */,
- 0 /* ad */,
- dnssec_checking_disabled /* cd */,
- 0 /* rcode */));
- }
-}
-
-int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu, bool dnssec_checking_disabled) {
- DnsPacket *p;
- int r;
-
- assert(ret);
-
- r = dns_packet_new(&p, protocol, mtu);
- if (r < 0)
- return r;
-
- /* Always set the TC bit to 0 initially.
- * If there are multiple packets later, we'll update the bit shortly before sending.
- */
- dns_packet_set_flags(p, dnssec_checking_disabled, false);
-
- *ret = p;
- return 0;
-}
-
-DnsPacket *dns_packet_ref(DnsPacket *p) {
-
- if (!p)
- return NULL;
-
- assert(!p->on_stack);
-
- 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);
- dns_resource_record_unref(p->opt);
-
- while ((s = hashmap_steal_first_key(p->names)))
- free(s);
- hashmap_free(p->names);
-
- free(p->_data);
-
- if (!p->on_stack)
- free(p);
-}
-
-DnsPacket *dns_packet_unref(DnsPacket *p) {
- if (!p)
- return NULL;
-
- assert(p->n_ref > 0);
-
- dns_packet_unref(p->more);
-
- 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;
-
- switch (p->protocol) {
-
- case DNS_PROTOCOL_LLMNR:
- /* RFC 4795, Section 2.1.1. says to discard all replies with QDCOUNT != 1 */
- if (DNS_PACKET_QDCOUNT(p) != 1)
- return -EBADMSG;
-
- break;
-
- case DNS_PROTOCOL_MDNS:
- /* RFC 6762, Section 18 */
- if (DNS_PACKET_RCODE(p) != 0)
- return -EBADMSG;
-
- break;
-
- default:
- break;
- }
-
- 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;
-
- switch (p->protocol) {
-
- case DNS_PROTOCOL_LLMNR:
- case DNS_PROTOCOL_DNS:
- /* RFC 4795, Section 2.1.1. says to discard all queries with QDCOUNT != 1 */
- if (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;
-
- break;
-
- case DNS_PROTOCOL_MDNS:
- /* RFC 6762, Section 18 */
- if (DNS_PACKET_AA(p) != 0 ||
- DNS_PACKET_RD(p) != 0 ||
- DNS_PACKET_RA(p) != 0 ||
- DNS_PACKET_AD(p) != 0 ||
- DNS_PACKET_CD(p) != 0 ||
- DNS_PACKET_RCODE(p) != 0)
- return -EBADMSG;
-
- break;
-
- default:
- break;
- }
-
- 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;
-}
-
-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(n, s, 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;
-
- unaligned_write_be16(d, 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;
-
- unaligned_write_be32(d, v);
-
- return 0;
-}
-
-int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start) {
- assert(p);
- assert(s);
-
- return dns_packet_append_raw_string(p, s, strlen(s), start);
-}
-
-int dns_packet_append_raw_string(DnsPacket *p, const void *s, size_t size, size_t *start) {
- void *d;
- int r;
-
- assert(p);
- assert(s || size == 0);
-
- if (size > 255)
- return -E2BIG;
-
- r = dns_packet_extend(p, 1 + size, &d, start);
- if (r < 0)
- return r;
-
- ((uint8_t*) d)[0] = (uint8_t) size;
-
- memcpy_safe(((uint8_t*) d) + 1, s, size);
-
- return 0;
-}
-
-int dns_packet_append_label(DnsPacket *p, const char *d, size_t l, bool canonical_candidate, size_t *start) {
- uint8_t *w;
- int r;
-
- /* Append a label to a packet. Optionally, does this in DNSSEC
- * canonical form, if this label is marked as a candidate for
- * it, and the canonical form logic is enabled for the
- * packet */
-
- assert(p);
- assert(d);
-
- if (l > DNS_LABEL_MAX)
- return -E2BIG;
-
- r = dns_packet_extend(p, 1 + l, (void**) &w, start);
- if (r < 0)
- return r;
-
- *(w++) = (uint8_t) l;
-
- if (p->canonical_form && canonical_candidate) {
- size_t i;
-
- /* Generate in canonical form, as defined by DNSSEC
- * RFC 4034, Section 6.2, i.e. all lower-case. */
-
- for (i = 0; i < l; i++)
- w[i] = (uint8_t) ascii_tolower(d[i]);
- } else
- /* Otherwise, just copy the string unaltered. This is
- * essential for DNS-SD, where the casing of labels
- * matters and needs to be retained. */
- memcpy(w, d, l);
-
- return 0;
-}
-
-int dns_packet_append_name(
- DnsPacket *p,
- const char *name,
- bool allow_compression,
- bool canonical_candidate,
- size_t *start) {
-
- size_t saved_size;
- int r;
-
- assert(p);
- assert(name);
-
- if (p->refuse_compression)
- allow_compression = false;
-
- saved_size = p->size;
-
- while (!dns_name_is_root(name)) {
- const char *z = name;
- char label[DNS_LABEL_MAX];
- size_t n = 0;
-
- 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;
- }
- }
-
- r = dns_label_unescape(&name, label, sizeof(label));
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_label(p, label, r, canonical_candidate, &n);
- if (r < 0)
- goto fail;
-
- if (allow_compression) {
- _cleanup_free_ char *s = NULL;
-
- s = strdup(z);
- if (!s) {
- r = -ENOMEM;
- goto fail;
- }
-
- 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, 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;
-}
-
-static int dns_packet_append_type_window(DnsPacket *p, uint8_t window, uint8_t length, const uint8_t *types, size_t *start) {
- size_t saved_size;
- int r;
-
- assert(p);
- assert(types);
- assert(length > 0);
-
- saved_size = p->size;
-
- r = dns_packet_append_uint8(p, window, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint8(p, length, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_blob(p, types, length, NULL);
- if (r < 0)
- goto fail;
-
- if (start)
- *start = saved_size;
-
- return 0;
-fail:
- dns_packet_truncate(p, saved_size);
- return r;
-}
-
-static int dns_packet_append_types(DnsPacket *p, Bitmap *types, size_t *start) {
- Iterator i;
- uint8_t window = 0;
- uint8_t entry = 0;
- uint8_t bitmaps[32] = {};
- unsigned n;
- size_t saved_size;
- int r;
-
- assert(p);
-
- saved_size = p->size;
-
- BITMAP_FOREACH(n, types, i) {
- assert(n <= 0xffff);
-
- if ((n >> 8) != window && bitmaps[entry / 8] != 0) {
- r = dns_packet_append_type_window(p, window, entry / 8 + 1, bitmaps, NULL);
- if (r < 0)
- goto fail;
-
- zero(bitmaps);
- }
-
- window = n >> 8;
- entry = n & 255;
-
- bitmaps[entry / 8] |= 1 << (7 - (entry % 8));
- }
-
- if (bitmaps[entry / 8] != 0) {
- r = dns_packet_append_type_window(p, window, entry / 8 + 1, bitmaps, NULL);
- if (r < 0)
- goto fail;
- }
-
- if (start)
- *start = saved_size;
-
- return 0;
-fail:
- dns_packet_truncate(p, saved_size);
- return r;
-}
-
-/* Append the OPT pseudo-RR described in RFC6891 */
-int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, int rcode, size_t *start) {
- size_t saved_size;
- int r;
-
- assert(p);
- /* we must never advertise supported packet size smaller than the legacy max */
- assert(max_udp_size >= DNS_PACKET_UNICAST_SIZE_MAX);
- assert(rcode >= 0);
- assert(rcode <= _DNS_RCODE_MAX);
-
- if (p->opt_start != (size_t) -1)
- return -EBUSY;
-
- assert(p->opt_size == (size_t) -1);
-
- saved_size = p->size;
-
- /* empty name */
- r = dns_packet_append_uint8(p, 0, NULL);
- if (r < 0)
- return r;
-
- /* type */
- r = dns_packet_append_uint16(p, DNS_TYPE_OPT, NULL);
- if (r < 0)
- goto fail;
-
- /* class: maximum udp packet that can be received */
- r = dns_packet_append_uint16(p, max_udp_size, NULL);
- if (r < 0)
- goto fail;
-
- /* extended RCODE and VERSION */
- r = dns_packet_append_uint16(p, ((uint16_t) rcode & 0x0FF0) << 4, NULL);
- if (r < 0)
- goto fail;
-
- /* flags: DNSSEC OK (DO), see RFC3225 */
- r = dns_packet_append_uint16(p, edns0_do ? EDNS0_OPT_DO : 0, NULL);
- if (r < 0)
- goto fail;
-
- /* RDLENGTH */
- if (edns0_do && !DNS_PACKET_QR(p)) {
- /* If DO is on and this is not a reply, also append RFC6975 Algorithm data */
-
- static const uint8_t rfc6975[] = {
-
- 0, 5, /* OPTION_CODE: DAU */
- 0, 6, /* LIST_LENGTH */
- DNSSEC_ALGORITHM_RSASHA1,
- DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1,
- DNSSEC_ALGORITHM_RSASHA256,
- DNSSEC_ALGORITHM_RSASHA512,
- DNSSEC_ALGORITHM_ECDSAP256SHA256,
- DNSSEC_ALGORITHM_ECDSAP384SHA384,
-
- 0, 6, /* OPTION_CODE: DHU */
- 0, 3, /* LIST_LENGTH */
- DNSSEC_DIGEST_SHA1,
- DNSSEC_DIGEST_SHA256,
- DNSSEC_DIGEST_SHA384,
-
- 0, 7, /* OPTION_CODE: N3U */
- 0, 1, /* LIST_LENGTH */
- NSEC3_ALGORITHM_SHA1,
- };
-
- r = dns_packet_append_uint16(p, sizeof(rfc6975), NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_blob(p, rfc6975, sizeof(rfc6975), NULL);
- } else
- r = dns_packet_append_uint16(p, 0, NULL);
- if (r < 0)
- goto fail;
-
- DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) + 1);
-
- p->opt_start = saved_size;
- p->opt_size = p->size - saved_size;
-
- if (start)
- *start = saved_size;
-
- return 0;
-
-fail:
- dns_packet_truncate(p, saved_size);
- return r;
-}
-
-int dns_packet_truncate_opt(DnsPacket *p) {
- assert(p);
-
- if (p->opt_start == (size_t) -1) {
- assert(p->opt_size == (size_t) -1);
- return 0;
- }
-
- assert(p->opt_size != (size_t) -1);
- assert(DNS_PACKET_ARCOUNT(p) > 0);
-
- if (p->opt_start + p->opt_size != p->size)
- return -EBUSY;
-
- dns_packet_truncate(p, p->opt_start);
- DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) - 1);
- p->opt_start = p->opt_size = (size_t) -1;
-
- return 1;
-}
-
-int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start) {
-
- size_t saved_size, rdlength_offset, end, rdlength, rds;
- 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;
-
- rds = p->size - saved_size;
-
- 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, false, 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);
- 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:
-
- if (!rr->txt.items) {
- /* RFC 6763, section 6.1 suggests to generate
- * single empty string for an empty array. */
-
- r = dns_packet_append_raw_string(p, NULL, 0, NULL);
- if (r < 0)
- goto fail;
- } else {
- DnsTxtItem *i;
-
- LIST_FOREACH(items, i, rr->txt.items) {
- r = dns_packet_append_raw_string(p, i->data, i->length, 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, false, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_name(p, rr->soa.rname, true, false, 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, false, 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_DS:
- r = dns_packet_append_uint16(p, rr->ds.key_tag, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint8(p, rr->ds.algorithm, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint8(p, rr->ds.digest_type, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_blob(p, rr->ds.digest, rr->ds.digest_size, 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.fingerprint, rr->sshfp.fingerprint_size, NULL);
- break;
-
- case DNS_TYPE_DNSKEY:
- r = dns_packet_append_uint16(p, rr->dnskey.flags, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint8(p, rr->dnskey.protocol, 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_uint16(p, rr->rrsig.key_tag, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_name(p, rr->rrsig.signer, false, true, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_blob(p, rr->rrsig.signature, rr->rrsig.signature_size, NULL);
- break;
-
- case DNS_TYPE_NSEC:
- r = dns_packet_append_name(p, rr->nsec.next_domain_name, false, false, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_types(p, rr->nsec.types, NULL);
- if (r < 0)
- goto fail;
-
- break;
-
- case DNS_TYPE_NSEC3:
- r = dns_packet_append_uint8(p, rr->nsec3.algorithm, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint8(p, rr->nsec3.flags, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint16(p, rr->nsec3.iterations, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint8(p, rr->nsec3.salt_size, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_blob(p, rr->nsec3.salt, rr->nsec3.salt_size, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint8(p, rr->nsec3.next_hashed_name_size, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_blob(p, rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_types(p, rr->nsec3.types, NULL);
- if (r < 0)
- goto fail;
-
- break;
-
- case DNS_TYPE_TLSA:
- r = dns_packet_append_uint8(p, rr->tlsa.cert_usage, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint8(p, rr->tlsa.selector, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_uint8(p, rr->tlsa.matching_type, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_blob(p, rr->tlsa.data, rr->tlsa.data_size, NULL);
- break;
-
- case DNS_TYPE_CAA:
- r = dns_packet_append_uint8(p, rr->caa.flags, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_string(p, rr->caa.tag, NULL);
- if (r < 0)
- goto fail;
-
- r = dns_packet_append_blob(p, rr->caa.value, rr->caa.value_size, NULL);
- break;
-
- case DNS_TYPE_OPT:
- case DNS_TYPE_OPENPGPKEY:
- case _DNS_TYPE_INVALID: /* unparseable */
- default:
-
- r = dns_packet_append_blob(p, rr->generic.data, rr->generic.data_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;
-
- if (rdata_start)
- *rdata_start = rds;
-
- return 0;
-
-fail:
- dns_packet_truncate(p, saved_size);
- return r;
-}
-
-int dns_packet_append_question(DnsPacket *p, DnsQuestion *q) {
- DnsResourceKey *key;
- int r;
-
- assert(p);
-
- DNS_QUESTION_FOREACH(key, q) {
- r = dns_packet_append_key(p, key, NULL);
- if (r < 0)
- return r;
- }
-
- return 0;
-}
-
-int dns_packet_append_answer(DnsPacket *p, DnsAnswer *a) {
- DnsResourceRecord *rr;
- int r;
-
- assert(p);
-
- DNS_ANSWER_FOREACH(rr, a) {
- r = dns_packet_append_rr(p, rr, NULL, NULL);
- if (r < 0)
- return r;
- }
-
- return 0;
-}
-
-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;
-}
-
-static int dns_packet_read_memdup(
- DnsPacket *p, size_t size,
- void **ret, size_t *ret_size,
- size_t *ret_start) {
-
- const void *src;
- size_t start;
- int r;
-
- assert(p);
- assert(ret);
-
- r = dns_packet_read(p, size, &src, &start);
- if (r < 0)
- return r;
-
- if (size <= 0)
- *ret = NULL;
- else {
- void *copy;
-
- copy = memdup(src, size);
- if (!copy)
- return -ENOMEM;
-
- *ret = copy;
- }
-
- if (ret_size)
- *ret_size = size;
- if (ret_start)
- *ret_start = start;
-
- 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 = unaligned_read_be16(d);
-
- 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 = unaligned_read_be32(d);
-
- return 0;
-}
-
-int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) {
- _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
- const void *d;
- char *t;
- uint8_t c;
- int r;
-
- assert(p);
- INIT_REWINDER(rewinder, p);
-
- r = dns_packet_read_uint8(p, &c, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read(p, c, &d, NULL);
- if (r < 0)
- return r;
-
- if (memchr(d, 0, c))
- return -EBADMSG;
-
- t = strndup(d, c);
- if (!t)
- return -ENOMEM;
-
- if (!utf8_is_valid(t)) {
- free(t);
- return -EBADMSG;
- }
-
- *ret = t;
-
- if (start)
- *start = rewinder.saved_rindex;
- CANCEL_REWINDER(rewinder);
-
- return 0;
-}
-
-int dns_packet_read_raw_string(DnsPacket *p, const void **ret, size_t *size, size_t *start) {
- _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
- uint8_t c;
- int r;
-
- assert(p);
- INIT_REWINDER(rewinder, p);
-
- r = dns_packet_read_uint8(p, &c, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read(p, c, ret, NULL);
- if (r < 0)
- return r;
-
- if (size)
- *size = c;
- if (start)
- *start = rewinder.saved_rindex;
- CANCEL_REWINDER(rewinder);
-
- return 0;
-}
-
-int dns_packet_read_name(
- DnsPacket *p,
- char **_ret,
- bool allow_compression,
- size_t *start) {
-
- _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
- size_t after_rindex = 0, jump_barrier;
- _cleanup_free_ char *ret = NULL;
- size_t n = 0, allocated = 0;
- bool first = true;
- int r;
-
- assert(p);
- assert(_ret);
- INIT_REWINDER(rewinder, p);
- jump_barrier = p->rindex;
-
- if (p->refuse_compression)
- allow_compression = false;
-
- for (;;) {
- uint8_t c, d;
-
- r = dns_packet_read_uint8(p, &c, NULL);
- if (r < 0)
- return r;
-
- if (c == 0)
- /* End of name */
- break;
- else if (c <= 63) {
- const char *label;
-
- /* Literal label */
- r = dns_packet_read(p, c, (const void**) &label, NULL);
- if (r < 0)
- return r;
-
- if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX))
- return -ENOMEM;
-
- if (first)
- first = false;
- else
- ret[n++] = '.';
-
- r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX);
- if (r < 0)
- return 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)
- return r;
-
- ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d;
- if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= jump_barrier)
- return -EBADMSG;
-
- if (after_rindex == 0)
- after_rindex = p->rindex;
-
- /* Jumps are limited to a "prior occurrence" (RFC-1035 4.1.4) */
- jump_barrier = ptr;
- p->rindex = ptr;
- } else
- return -EBADMSG;
- }
-
- if (!GREEDY_REALLOC(ret, allocated, n + 1))
- return -ENOMEM;
-
- ret[n] = 0;
-
- if (after_rindex != 0)
- p->rindex= after_rindex;
-
- *_ret = ret;
- ret = NULL;
-
- if (start)
- *start = rewinder.saved_rindex;
- CANCEL_REWINDER(rewinder);
-
- return 0;
-}
-
-static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *start) {
- uint8_t window;
- uint8_t length;
- const uint8_t *bitmap;
- uint8_t bit = 0;
- unsigned i;
- bool found = false;
- _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
- int r;
-
- assert(p);
- assert(types);
- INIT_REWINDER(rewinder, p);
-
- r = bitmap_ensure_allocated(types);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &window, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &length, NULL);
- if (r < 0)
- return r;
-
- if (length == 0 || length > 32)
- return -EBADMSG;
-
- r = dns_packet_read(p, length, (const void **)&bitmap, NULL);
- if (r < 0)
- return r;
-
- for (i = 0; i < length; i++) {
- uint8_t bitmask = 1 << 7;
-
- if (!bitmap[i]) {
- found = false;
- bit += 8;
- continue;
- }
-
- found = true;
-
- while (bitmask) {
- if (bitmap[i] & bitmask) {
- uint16_t n;
-
- n = (uint16_t) window << 8 | (uint16_t) bit;
-
- /* Ignore pseudo-types. see RFC4034 section 4.1.2 */
- if (dns_type_is_pseudo(n))
- continue;
-
- r = bitmap_set(*types, n);
- if (r < 0)
- return r;
- }
-
- bit++;
- bitmask >>= 1;
- }
- }
-
- if (!found)
- return -EBADMSG;
-
- if (start)
- *start = rewinder.saved_rindex;
- CANCEL_REWINDER(rewinder);
-
- return 0;
-}
-
-static int dns_packet_read_type_windows(DnsPacket *p, Bitmap **types, size_t size, size_t *start) {
- _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
- int r;
-
- INIT_REWINDER(rewinder, p);
-
- while (p->rindex < rewinder.saved_rindex + size) {
- r = dns_packet_read_type_window(p, types, NULL);
- if (r < 0)
- return r;
-
- /* don't read past end of current RR */
- if (p->rindex > rewinder.saved_rindex + size)
- return -EBADMSG;
- }
-
- if (p->rindex != rewinder.saved_rindex + size)
- return -EBADMSG;
-
- if (start)
- *start = rewinder.saved_rindex;
- CANCEL_REWINDER(rewinder);
-
- return 0;
-}
-
-int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flush, size_t *start) {
- _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
- _cleanup_free_ char *name = NULL;
- bool cache_flush = false;
- uint16_t class, type;
- DnsResourceKey *key;
- int r;
-
- assert(p);
- assert(ret);
- INIT_REWINDER(rewinder, p);
-
- r = dns_packet_read_name(p, &name, true, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint16(p, &type, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint16(p, &class, NULL);
- if (r < 0)
- return r;
-
- if (p->protocol == DNS_PROTOCOL_MDNS) {
- /* See RFC6762, Section 10.2 */
-
- if (type != DNS_TYPE_OPT && (class & MDNS_RR_CACHE_FLUSH)) {
- class &= ~MDNS_RR_CACHE_FLUSH;
- cache_flush = true;
- }
- }
-
- key = dns_resource_key_new_consume(class, type, name);
- if (!key)
- return -ENOMEM;
-
- name = NULL;
- *ret = key;
-
- if (ret_cache_flush)
- *ret_cache_flush = cache_flush;
- if (start)
- *start = rewinder.saved_rindex;
- CANCEL_REWINDER(rewinder);
-
- 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);
-}
-
-int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_flush, size_t *start) {
- _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
- _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
- _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
- size_t offset;
- uint16_t rdlength;
- bool cache_flush;
- int r;
-
- assert(p);
- assert(ret);
-
- INIT_REWINDER(rewinder, p);
-
- r = dns_packet_read_key(p, &key, &cache_flush, NULL);
- if (r < 0)
- return r;
-
- if (!dns_class_is_valid_rr(key->class) || !dns_type_is_valid_rr(key->type))
- return -EBADMSG;
-
- rr = dns_resource_record_new(key);
- if (!rr)
- return -ENOMEM;
-
- r = dns_packet_read_uint32(p, &rr->ttl, NULL);
- if (r < 0)
- return r;
-
- /* RFC 2181, Section 8, suggests to
- * treat a TTL with the MSB set as a zero TTL. */
- if (rr->ttl & UINT32_C(0x80000000))
- rr->ttl = 0;
-
- r = dns_packet_read_uint16(p, &rdlength, NULL);
- if (r < 0)
- return r;
-
- if (p->rindex + rdlength > p->size)
- return -EBADMSG;
-
- offset = p->rindex;
-
- switch (rr->key->type) {
-
- case DNS_TYPE_SRV:
- r = dns_packet_read_uint16(p, &rr->srv.priority, NULL);
- if (r < 0)
- return r;
- r = dns_packet_read_uint16(p, &rr->srv.weight, NULL);
- if (r < 0)
- return r;
- r = dns_packet_read_uint16(p, &rr->srv.port, NULL);
- if (r < 0)
- return r;
- 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)
- return r;
-
- r = dns_packet_read_string(p, &rr->hinfo.os, NULL);
- break;
-
- case DNS_TYPE_SPF: /* exactly the same as TXT */
- case DNS_TYPE_TXT:
- if (rdlength <= 0) {
- DnsTxtItem *i;
- /* RFC 6763, section 6.1 suggests to treat
- * empty TXT RRs as equivalent to a TXT record
- * with a single empty string. */
-
- i = malloc0(offsetof(DnsTxtItem, data) + 1); /* for safety reasons we add an extra NUL byte */
- if (!i)
- return -ENOMEM;
-
- rr->txt.items = i;
- } else {
- DnsTxtItem *last = NULL;
-
- while (p->rindex < offset + rdlength) {
- DnsTxtItem *i;
- const void *data;
- size_t sz;
-
- r = dns_packet_read_raw_string(p, &data, &sz, NULL);
- if (r < 0)
- return r;
-
- i = malloc0(offsetof(DnsTxtItem, data) + sz + 1); /* extra NUL byte at the end */
- if (!i)
- return -ENOMEM;
-
- memcpy(i->data, data, sz);
- i->length = sz;
-
- LIST_INSERT_AFTER(items, rr->txt.items, last, i);
- last = i;
- }
- }
-
- 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)
- return r;
-
- r = dns_packet_read_name(p, &rr->soa.rname, true, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint32(p, &rr->soa.serial, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint32(p, &rr->soa.refresh, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint32(p, &rr->soa.retry, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint32(p, &rr->soa.expire, NULL);
- if (r < 0)
- return r;
-
- 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)
- return r;
-
- 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)
- return r;
-
- if (t == 0) {
- rr->loc.version = t;
-
- r = dns_packet_read_uint8(p, &rr->loc.size, NULL);
- if (r < 0)
- return r;
-
- if (!loc_size_ok(rr->loc.size))
- return -EBADMSG;
-
- r = dns_packet_read_uint8(p, &rr->loc.horiz_pre, NULL);
- if (r < 0)
- return r;
-
- if (!loc_size_ok(rr->loc.horiz_pre))
- return -EBADMSG;
-
- r = dns_packet_read_uint8(p, &rr->loc.vert_pre, NULL);
- if (r < 0)
- return r;
-
- if (!loc_size_ok(rr->loc.vert_pre))
- return -EBADMSG;
-
- r = dns_packet_read_uint32(p, &rr->loc.latitude, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint32(p, &rr->loc.longitude, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint32(p, &rr->loc.altitude, NULL);
- if (r < 0)
- return r;
-
- break;
- } else {
- dns_packet_rewind(p, pos);
- rr->unparseable = true;
- goto unparseable;
- }
- }
-
- case DNS_TYPE_DS:
- r = dns_packet_read_uint16(p, &rr->ds.key_tag, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->ds.algorithm, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->ds.digest_type, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_memdup(p, rdlength - 4,
- &rr->ds.digest, &rr->ds.digest_size,
- NULL);
- if (r < 0)
- return r;
-
- if (rr->ds.digest_size <= 0)
- /* the accepted size depends on the algorithm, but for now
- just ensure that the value is greater than zero */
- return -EBADMSG;
-
- break;
-
- case DNS_TYPE_SSHFP:
- r = dns_packet_read_uint8(p, &rr->sshfp.algorithm, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->sshfp.fptype, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_memdup(p, rdlength - 2,
- &rr->sshfp.fingerprint, &rr->sshfp.fingerprint_size,
- NULL);
-
- if (rr->sshfp.fingerprint_size <= 0)
- /* the accepted size depends on the algorithm, but for now
- just ensure that the value is greater than zero */
- return -EBADMSG;
-
- break;
-
- case DNS_TYPE_DNSKEY:
- r = dns_packet_read_uint16(p, &rr->dnskey.flags, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->dnskey.protocol, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->dnskey.algorithm, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_memdup(p, rdlength - 4,
- &rr->dnskey.key, &rr->dnskey.key_size,
- NULL);
-
- if (rr->dnskey.key_size <= 0)
- /* the accepted size depends on the algorithm, but for now
- just ensure that the value is greater than zero */
- return -EBADMSG;
-
- break;
-
- case DNS_TYPE_RRSIG:
- r = dns_packet_read_uint16(p, &rr->rrsig.type_covered, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->rrsig.algorithm, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->rrsig.labels, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint32(p, &rr->rrsig.original_ttl, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint32(p, &rr->rrsig.expiration, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint32(p, &rr->rrsig.inception, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint16(p, &rr->rrsig.key_tag, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_name(p, &rr->rrsig.signer, false, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_memdup(p, offset + rdlength - p->rindex,
- &rr->rrsig.signature, &rr->rrsig.signature_size,
- NULL);
-
- if (rr->rrsig.signature_size <= 0)
- /* the accepted size depends on the algorithm, but for now
- just ensure that the value is greater than zero */
- return -EBADMSG;
-
- break;
-
- case DNS_TYPE_NSEC: {
-
- /*
- * RFC6762, section 18.14 explictly states mDNS should use name compression.
- * This contradicts RFC3845, section 2.1.1
- */
-
- bool allow_compressed = p->protocol == DNS_PROTOCOL_MDNS;
-
- r = dns_packet_read_name(p, &rr->nsec.next_domain_name, allow_compressed, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_type_windows(p, &rr->nsec.types, offset + rdlength - p->rindex, NULL);
-
- /* We accept empty NSEC bitmaps. The bit indicating the presence of the NSEC record itself
- * is redundant and in e.g., RFC4956 this fact is used to define a use for NSEC records
- * without the NSEC bit set. */
-
- break;
- }
- case DNS_TYPE_NSEC3: {
- uint8_t size;
-
- r = dns_packet_read_uint8(p, &rr->nsec3.algorithm, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->nsec3.flags, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint16(p, &rr->nsec3.iterations, NULL);
- if (r < 0)
- return r;
-
- /* this may be zero */
- r = dns_packet_read_uint8(p, &size, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_memdup(p, size, &rr->nsec3.salt, &rr->nsec3.salt_size, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &size, NULL);
- if (r < 0)
- return r;
-
- if (size <= 0)
- return -EBADMSG;
-
- r = dns_packet_read_memdup(p, size,
- &rr->nsec3.next_hashed_name, &rr->nsec3.next_hashed_name_size,
- NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_type_windows(p, &rr->nsec3.types, offset + rdlength - p->rindex, NULL);
-
- /* empty non-terminals can have NSEC3 records, so empty bitmaps are allowed */
-
- break;
- }
-
- case DNS_TYPE_TLSA:
- r = dns_packet_read_uint8(p, &rr->tlsa.cert_usage, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->tlsa.selector, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_uint8(p, &rr->tlsa.matching_type, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_memdup(p, rdlength - 3,
- &rr->tlsa.data, &rr->tlsa.data_size,
- NULL);
-
- if (rr->tlsa.data_size <= 0)
- /* the accepted size depends on the algorithm, but for now
- just ensure that the value is greater than zero */
- return -EBADMSG;
-
- break;
-
- case DNS_TYPE_CAA:
- r = dns_packet_read_uint8(p, &rr->caa.flags, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_string(p, &rr->caa.tag, NULL);
- if (r < 0)
- return r;
-
- r = dns_packet_read_memdup(p,
- rdlength + offset - p->rindex,
- &rr->caa.value, &rr->caa.value_size, NULL);
-
- break;
-
- case DNS_TYPE_OPT: /* we only care about the header of OPT for now. */
- case DNS_TYPE_OPENPGPKEY:
- default:
- unparseable:
- r = dns_packet_read_memdup(p, rdlength, &rr->generic.data, &rr->generic.data_size, NULL);
-
- break;
- }
- if (r < 0)
- return r;
- if (p->rindex != offset + rdlength)
- return -EBADMSG;
-
- *ret = rr;
- rr = NULL;
-
- if (ret_cache_flush)
- *ret_cache_flush = cache_flush;
- if (start)
- *start = rewinder.saved_rindex;
- CANCEL_REWINDER(rewinder);
-
- return 0;
-}
-
-static bool opt_is_good(DnsResourceRecord *rr, bool *rfc6975) {
- const uint8_t* p;
- bool found_dau_dhu_n3u = false;
- size_t l;
-
- /* Checks whether the specified OPT RR is well-formed and whether it contains RFC6975 data (which is not OK in
- * a reply). */
-
- assert(rr);
- assert(rr->key->type == DNS_TYPE_OPT);
-
- /* Check that the version is 0 */
- if (((rr->ttl >> 16) & UINT32_C(0xFF)) != 0) {
- *rfc6975 = false;
- return true; /* if it's not version 0, it's OK, but we will ignore the OPT field contents */
- }
-
- p = rr->opt.data;
- l = rr->opt.data_size;
- while (l > 0) {
- uint16_t option_code, option_length;
-
- /* At least four bytes for OPTION-CODE and OPTION-LENGTH are required */
- if (l < 4U)
- return false;
-
- option_code = unaligned_read_be16(p);
- option_length = unaligned_read_be16(p + 2);
-
- if (l < option_length + 4U)
- return false;
-
- /* RFC 6975 DAU, DHU or N3U fields found. */
- if (IN_SET(option_code, 5, 6, 7))
- found_dau_dhu_n3u = true;
-
- p += option_length + 4U;
- l -= option_length + 4U;
- }
-
- *rfc6975 = found_dau_dhu_n3u;
- return true;
-}
-
-int dns_packet_extract(DnsPacket *p) {
- _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
- _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
- _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = {};
- unsigned n, i;
- int r;
-
- if (p->extracted)
- return 0;
-
- INIT_REWINDER(rewinder, p);
- dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE);
-
- n = DNS_PACKET_QDCOUNT(p);
- if (n > 0) {
- question = dns_question_new(n);
- if (!question)
- return -ENOMEM;
-
- for (i = 0; i < n; i++) {
- _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
- bool cache_flush;
-
- r = dns_packet_read_key(p, &key, &cache_flush, NULL);
- if (r < 0)
- return r;
-
- if (cache_flush)
- return -EBADMSG;
-
- if (!dns_type_is_valid_query(key->type))
- return -EBADMSG;
-
- r = dns_question_add(question, key);
- if (r < 0)
- return r;
- }
- }
-
- n = DNS_PACKET_RRCOUNT(p);
- if (n > 0) {
- _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *previous = NULL;
- bool bad_opt = false;
-
- answer = dns_answer_new(n);
- if (!answer)
- return -ENOMEM;
-
- for (i = 0; i < n; i++) {
- _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
- bool cache_flush = false;
-
- r = dns_packet_read_rr(p, &rr, &cache_flush, NULL);
- if (r < 0)
- return r;
-
- /* Try to reduce memory usage a bit */
- if (previous)
- dns_resource_key_reduce(&rr->key, &previous->key);
-
- if (rr->key->type == DNS_TYPE_OPT) {
- bool has_rfc6975;
-
- if (p->opt || bad_opt) {
- /* Multiple OPT RRs? if so, let's ignore all, because there's something wrong
- * with the server, and if one is valid we wouldn't know which one. */
- log_debug("Multiple OPT RRs detected, ignoring all.");
- bad_opt = true;
- continue;
- }
-
- if (!dns_name_is_root(dns_resource_key_name(rr->key))) {
- /* If the OPT RR is not owned by the root domain, then it is bad, let's ignore
- * it. */
- log_debug("OPT RR is not owned by root domain, ignoring.");
- bad_opt = true;
- continue;
- }
-
- if (i < DNS_PACKET_ANCOUNT(p) + DNS_PACKET_NSCOUNT(p)) {
- /* OPT RR is in the wrong section? Some Belkin routers do this. This is a hint
- * the EDNS implementation is borked, like the Belkin one is, hence ignore
- * it. */
- log_debug("OPT RR in wrong section, ignoring.");
- bad_opt = true;
- continue;
- }
-
- if (!opt_is_good(rr, &has_rfc6975)) {
- log_debug("Malformed OPT RR, ignoring.");
- bad_opt = true;
- continue;
- }
-
- if (DNS_PACKET_QR(p)) {
- /* Additional checks for responses */
-
- if (!DNS_RESOURCE_RECORD_OPT_VERSION_SUPPORTED(rr)) {
- /* If this is a reply and we don't know the EDNS version then something
- * is weird... */
- log_debug("EDNS version newer that our request, bad server.");
- return -EBADMSG;
- }
-
- if (has_rfc6975) {
- /* If the OPT RR contains RFC6975 algorithm data, then this is indication that
- * the server just copied the OPT it got from us (which contained that data)
- * back into the reply. If so, then it doesn't properly support EDNS, as
- * RFC6975 makes it very clear that the algorithm data should only be contained
- * in questions, never in replies. Crappy Belkin routers copy the OPT data for
- * example, hence let's detect this so that we downgrade early. */
- log_debug("OPT RR contained RFC6975 data, ignoring.");
- bad_opt = true;
- continue;
- }
- }
-
- p->opt = dns_resource_record_ref(rr);
- } else {
-
- /* According to RFC 4795, section 2.9. only the RRs from the Answer section shall be
- * cached. Hence mark only those RRs as cacheable by default, but not the ones from the
- * Additional or Authority sections. */
-
- r = dns_answer_add(answer, rr, p->ifindex,
- (i < DNS_PACKET_ANCOUNT(p) ? DNS_ANSWER_CACHEABLE : 0) |
- (p->protocol == DNS_PROTOCOL_MDNS && !cache_flush ? DNS_ANSWER_SHARED_OWNER : 0));
- if (r < 0)
- return r;
- }
-
- /* Remember this RR, so that we potentically can merge it's ->key object with the next RR. Note
- * that we only do this if we actually decided to keep the RR around. */
- dns_resource_record_unref(previous);
- previous = dns_resource_record_ref(rr);
- }
-
- if (bad_opt)
- p->opt = dns_resource_record_unref(p->opt);
- }
-
- p->question = question;
- question = NULL;
-
- p->answer = answer;
- answer = NULL;
-
- p->extracted = true;
-
- /* no CANCEL, always rewind */
- return 0;
-}
-
-int dns_packet_is_reply_for(DnsPacket *p, const DnsResourceKey *key) {
- int r;
-
- assert(p);
- assert(key);
-
- /* Checks if the specified packet is a reply for the specified
- * key and the specified key is the only one in the question
- * section. */
-
- if (DNS_PACKET_QR(p) != 1)
- return 0;
-
- /* Let's unpack the packet, if that hasn't happened yet. */
- r = dns_packet_extract(p);
- if (r < 0)
- return r;
-
- if (p->question->n_keys != 1)
- return 0;
-
- return dns_resource_key_equal(p->question->keys[0], key);
-}
-
-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",
- [DNS_RCODE_BADCOOKIE] = "BADCOOKIE",
-};
-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);
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-01 10:38:10 +0000