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Diffstat (limited to 'src/resolve/resolved-dns-packet.c')
-rw-r--r--src/resolve/resolved-dns-packet.c209
1 files changed, 127 insertions, 82 deletions
diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index 75ca23fd08..f753b3522f 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -65,30 +65,44 @@ int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) {
return 0;
}
-int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu) {
- DnsPacket *p;
- DnsPacketHeader *h;
- int r;
+void dns_packet_set_flags(DnsPacket *p, bool dnssec_checking_disabled, bool truncated) {
- assert(ret);
+ DnsPacketHeader *h;
- r = dns_packet_new(&p, protocol, mtu);
- if (r < 0)
- return r;
+ assert(p);
h = DNS_PACKET_HEADER(p);
- if (protocol == DNS_PROTOCOL_LLMNR)
+ 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/* tc */,
0 /* t */,
0 /* ra */,
0 /* ad */,
0 /* cd */,
0 /* rcode */));
- else
+ 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 */,
@@ -96,8 +110,25 @@ int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu) {
1 /* rd (ask for recursion) */,
0 /* ra */,
0 /* ad */,
- 0 /* cd */,
+ 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;
@@ -108,6 +139,8 @@ DnsPacket *dns_packet_ref(DnsPacket *p) {
if (!p)
return NULL;
+ assert(!p->on_stack);
+
assert(p->n_ref > 0);
p->n_ref++;
return p;
@@ -126,7 +159,9 @@ static void dns_packet_free(DnsPacket *p) {
hashmap_free(p->names);
free(p->_data);
- free(p);
+
+ if (!p->on_stack)
+ free(p);
}
DnsPacket *dns_packet_unref(DnsPacket *p) {
@@ -135,6 +170,9 @@ DnsPacket *dns_packet_unref(DnsPacket *p) {
assert(p->n_ref > 0);
+ if (p->more)
+ dns_packet_unref(p->more);
+
if (p->n_ref == 1)
dns_packet_free(p);
else
@@ -178,6 +216,13 @@ int dns_packet_validate_reply(DnsPacket *p) {
break;
+ case DNS_PROTOCOL_MDNS:
+ /* RFC 6762, Section 18 */
+ if (DNS_PACKET_RCODE(p) != 0)
+ return -EBADMSG;
+
+ break;
+
default:
break;
}
@@ -219,6 +264,18 @@ int dns_packet_validate_query(DnsPacket *p) {
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;
}
@@ -351,25 +408,10 @@ int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start) {
}
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;
+ 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) {
@@ -395,7 +437,7 @@ int dns_packet_append_raw_string(DnsPacket *p, const void *s, size_t size, size_
}
int dns_packet_append_label(DnsPacket *p, const char *d, size_t l, size_t *start) {
- void *w;
+ uint8_t *w;
int r;
assert(p);
@@ -404,12 +446,29 @@ int dns_packet_append_label(DnsPacket *p, const char *d, size_t l, size_t *start
if (l > DNS_LABEL_MAX)
return -E2BIG;
- r = dns_packet_extend(p, 1 + l, &w, start);
+ r = dns_packet_extend(p, 1 + l, (void**) &w, start);
if (r < 0)
return r;
- ((uint8_t*) w)[0] = (uint8_t) l;
- memcpy(((uint8_t*) w) + 1, d, l);
+ *(w++) = (uint8_t) l;
+
+ if (p->canonical_form) {
+ 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++) {
+ if (d[i] >= 'A' && d[i] <= 'Z')
+ w[i] = (uint8_t) (d[i] - 'A' + 'a');
+ else
+ w[i] = (uint8_t) 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;
}
@@ -662,8 +721,8 @@ fail:
return r;
}
-int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start) {
- size_t saved_size, rdlength_offset, end, rdlength;
+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);
@@ -684,6 +743,8 @@ int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *star
if (r < 0)
goto fail;
+ rds = p->size - saved_size;
+
switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) {
case DNS_TYPE_SRV:
@@ -841,11 +902,11 @@ int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *star
break;
case DNS_TYPE_DNSKEY:
- r = dns_packet_append_uint16(p, dnskey_to_flags(rr), NULL);
+ r = dns_packet_append_uint16(p, rr->dnskey.flags, NULL);
if (r < 0)
goto fail;
- r = dns_packet_append_uint8(p, 3u, NULL);
+ r = dns_packet_append_uint8(p, rr->dnskey.protocol, NULL);
if (r < 0)
goto fail;
@@ -962,6 +1023,9 @@ int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *star
if (start)
*start = saved_size;
+ if (rdata_start)
+ *rdata_start = rds;
+
return 0;
fail:
@@ -1381,6 +1445,7 @@ fail:
int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, size_t *start) {
_cleanup_free_ char *name = NULL;
+ bool cache_flush = false;
uint16_t class, type;
DnsResourceKey *key;
size_t saved_rindex;
@@ -1403,12 +1468,23 @@ int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, size_t *start) {
if (r < 0)
goto fail;
+ if (p->protocol == DNS_PROTOCOL_MDNS) {
+ /* See RFC6762, Section 10.2 */
+
+ if (class & MDNS_RR_CACHE_FLUSH) {
+ class &= ~MDNS_RR_CACHE_FLUSH;
+ cache_flush = true;
+ }
+ }
+
key = dns_resource_key_new_consume(class, type, name);
if (!key) {
r = -ENOMEM;
goto fail;
}
+ key->cache_flush = cache_flush;
+
name = NULL;
*ret = key;
@@ -1427,17 +1503,6 @@ static bool loc_size_ok(uint8_t size) {
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;
@@ -1706,28 +1771,15 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
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);
+ case DNS_TYPE_DNSKEY:
+ r = dns_packet_read_uint16(p, &rr->dnskey.flags, NULL);
if (r < 0)
goto fail;
- r = dns_packet_read_uint8(p, &proto, NULL);
+ r = dns_packet_read_uint8(p, &rr->dnskey.protocol, 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;
@@ -1744,7 +1796,6 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
}
break;
- }
case DNS_TYPE_RRSIG:
r = dns_packet_read_uint16(p, &rr->rrsig.type_covered, NULL);
@@ -1792,8 +1843,16 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
break;
- case DNS_TYPE_NSEC:
- r = dns_packet_read_name(p, &rr->nsec.next_domain_name, false, NULL);
+ case DNS_TYPE_NSEC: {
+
+ /*
+ * RFC6762, section 18.14 explicly 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)
goto fail;
@@ -1806,7 +1865,7 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
* without the NSEC bit set. */
break;
-
+ }
case DNS_TYPE_NSEC3: {
uint8_t size;
@@ -1976,17 +2035,3 @@ static const char* const dns_protocol_table[_DNS_PROTOCOL_MAX] = {
[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_DSA_NSEC3_SHA1] = "DSA-NSEC3-SHA1",
- [DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1] = "RSASHA1-NSEC3-SHA1",
- [DNSSEC_ALGORITHM_INDIRECT] = "INDIRECT",
- [DNSSEC_ALGORITHM_PRIVATEDNS] = "PRIVATEDNS",
- [DNSSEC_ALGORITHM_PRIVATEOID] = "PRIVATEOID",
-};
-DEFINE_STRING_TABLE_LOOKUP(dnssec_algorithm, int);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-13 07:48:02 +0000