#include "utf8.h"
#include "util.h"
#include "strv.h"
+#include "unaligned.h"
#include "resolved-dns-domain.h"
#include "resolved-dns-packet.h"
if (r < 0)
return r;
- ((uint8_t*) d)[0] = (uint8_t) (v >> 8);
- ((uint8_t*) d)[1] = (uint8_t) v;
+ unaligned_write_be16(d, v);
return 0;
}
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;
+ unaligned_write_be32(d, v);
return 0;
}
return 0;
}
-int dns_packet_append_name(DnsPacket *p, const char *name, size_t *start) {
+int dns_packet_append_name(DnsPacket *p, const char *name,
+ bool allow_compression, size_t *start) {
size_t saved_size;
int r;
while (*name) {
_cleanup_free_ char *s = NULL;
char label[DNS_LABEL_MAX];
- size_t n;
+ size_t n = 0;
int k;
- n = PTR_TO_SIZE(hashmap_get(p->names, name));
+ if (allow_compression)
+ n = PTR_TO_SIZE(hashmap_get(p->names, name));
if (n > 0) {
assert(n < p->size);
if (r < 0)
goto fail;
- r = hashmap_ensure_allocated(&p->names, dns_name_hash_func, dns_name_compare_func);
- 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;
+ r = hashmap_put(p->names, s, SIZE_TO_PTR(n));
+ if (r < 0)
+ goto fail;
- s = NULL;
+ s = NULL;
+ }
}
r = dns_packet_append_uint8(p, 0, NULL);
saved_size = p->size;
- r = dns_packet_append_name(p, DNS_RESOURCE_KEY_NAME(k), NULL);
+ r = dns_packet_append_name(p, DNS_RESOURCE_KEY_NAME(k), true, NULL);
if (r < 0)
goto fail;
if (r < 0)
goto fail;
- r = dns_packet_append_name(p, rr->srv.name, NULL);
+ 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, NULL);
+ r = dns_packet_append_name(p, rr->ptr.name, true, NULL);
break;
case DNS_TYPE_HINFO:
case DNS_TYPE_TXT: {
char **s;
- STRV_FOREACH(s, rr->txt.strings) {
- r = dns_packet_append_string(p, *s, NULL);
+ if (strv_isempty(rr->txt.strings)) {
+ /* RFC 6763, section 6.1 suggests to generate
+ * single empty string for an empty array. */
+
+ r = dns_packet_append_string(p, "", NULL);
if (r < 0)
goto fail;
+ } else {
+ 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_SOA:
- r = dns_packet_append_name(p, rr->soa.mname, NULL);
+ 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, NULL);
+ r = dns_packet_append_name(p, rr->soa.rname, true, NULL);
if (r < 0)
goto fail;
if (r < 0)
goto fail;
- r = dns_packet_append_name(p, rr->mx.exchange, NULL);
+ r = dns_packet_append_name(p, rr->mx.exchange, true, NULL);
break;
case DNS_TYPE_LOC:
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:
if (r < 0)
return r;
- *ret = (((uint16_t) ((uint8_t*) d)[0]) << 8) |
- ((uint16_t) ((uint8_t*) d)[1]);
+ *ret = unaligned_read_be16(d);
+
return 0;
}
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]);
+ *ret = unaligned_read_be32(d);
return 0;
}
return r;
}
-int dns_packet_read_name(DnsPacket *p, char **_ret, size_t *start) {
- size_t saved_rindex, after_rindex = 0;
+int dns_packet_read_name(DnsPacket *p, char **_ret,
+ bool allow_compression, size_t *start) {
+ size_t saved_rindex, after_rindex = 0, jump_barrier;
_cleanup_free_ char *ret = NULL;
size_t n = 0, allocated = 0;
bool first = true;
assert(_ret);
saved_rindex = p->rindex;
+ jump_barrier = p->rindex;
for (;;) {
uint8_t c, d;
memcpy(ret + n, t, r);
n += r;
continue;
- } else if ((c & 0xc0) == 0xc0) {
+ } else if (allow_compression && (c & 0xc0) == 0xc0) {
uint16_t ptr;
/* Pointer */
goto fail;
ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d;
- if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= saved_rindex) {
+ if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= jump_barrier) {
r = -EBADMSG;
goto fail;
}
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
+ } else {
+ r = -EBADMSG;
goto fail;
+ }
}
if (!GREEDY_REALLOC(ret, allocated, n + 1)) {
saved_rindex = p->rindex;
- r = dns_packet_read_name(p, &name, NULL);
+ r = dns_packet_read_name(p, &name, true, NULL);
if (r < 0)
goto fail;
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;
r = dns_packet_read_uint16(p, &rr->srv.port, NULL);
if (r < 0)
goto fail;
- r = dns_packet_read_name(p, &rr->srv.name, NULL);
+ 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, NULL);
+ r = dns_packet_read_name(p, &rr->ptr.name, true, NULL);
break;
case DNS_TYPE_HINFO:
break;
case DNS_TYPE_SPF: /* exactly the same as TXT */
- case DNS_TYPE_TXT: {
- char *s;
+ case DNS_TYPE_TXT:
+ if (rdlength <= 0) {
+ /* RFC 6763, section 6.1 suggests to treat
+ * empty TXT RRs as equivalent to a TXT record
+ * with a single empty string. */
- while (p->rindex < offset + rdlength) {
- r = dns_packet_read_string(p, &s, NULL);
+ r = strv_extend(&rr->txt.strings, "");
if (r < 0)
goto fail;
+ } else {
+ while (p->rindex < offset + rdlength) {
+ char *s;
- r = strv_consume(&rr->txt.strings, s);
- if (r < 0)
- goto fail;
+ 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_SOA:
- r = dns_packet_read_name(p, &rr->soa.mname, NULL);
+ 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, NULL);
+ r = dns_packet_read_name(p, &rr->soa.rname, true, NULL);
if (r < 0)
goto fail;
if (r < 0)
goto fail;
- r = dns_packet_read_name(p, &rr->mx.exchange, NULL);
+ r = dns_packet_read_name(p, &rr->mx.exchange, true, NULL);
break;
case DNS_TYPE_LOC: {
}
case DNS_TYPE_SSHFP:
-
r = dns_packet_read_uint8(p, &rr->sshfp.algorithm, NULL);
if (r < 0)
goto fail;
if (r < 0)
goto fail;
- r = dns_packet_read(p, rdlength - 2, &d, NULL);
+ 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;
- rr->sshfp.key = memdup(d, rdlength - 2);
- if (!rr->sshfp.key) {
- r = -ENOMEM;
+ 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;
}
- rr->sshfp.key_size = rdlength - 2;
+ 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:
unsigned n, i;
int r;
+ if (p->extracted)
+ return 0;
+
saved_rindex = p->rindex;
dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE);
p->answer = answer;
answer = NULL;
+ p->extracted = true;
+
r = 0;
finish:
[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);