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path: root/src/lib/krb5/os/locate_kdc.c
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Diffstat (limited to 'src/lib/krb5/os/locate_kdc.c')
-rw-r--r--src/lib/krb5/os/locate_kdc.c242
1 files changed, 23 insertions, 219 deletions
diff --git a/src/lib/krb5/os/locate_kdc.c b/src/lib/krb5/os/locate_kdc.c
index 9c9fed4..ce90127 100644
--- a/src/lib/krb5/os/locate_kdc.c
+++ b/src/lib/krb5/os/locate_kdc.c
@@ -502,12 +502,6 @@ krb5_locate_srv_conf(krb5_context context, const krb5_data *realm,
}
#endif
-#ifdef KRB5_DNS_LOOKUP
-
-/*
- * Lookup a KDC via DNS SRV records
- */
-
static krb5_error_code
krb5_locate_srv_dns_1 (const krb5_data *realm,
const char *service,
@@ -515,196 +509,14 @@ krb5_locate_srv_dns_1 (const krb5_data *realm,
struct addrlist *addrlist,
int family)
{
- union {
- unsigned char bytes[2048];
- HEADER hdr;
- } answer;
- unsigned char *p=NULL;
- char host[MAX_DNS_NAMELEN], *h;
- int type, rrclass;
- int priority, weight, size, len, numanswers, numqueries, rdlen;
- unsigned short port;
- const int hdrsize = sizeof(HEADER);
- struct srv_dns_entry {
- struct srv_dns_entry *next;
- int priority;
- int weight;
- unsigned short port;
- char *host;
- };
-
struct srv_dns_entry *head = NULL;
- struct srv_dns_entry *srv = NULL, *entry = NULL;
+ struct srv_dns_entry *entry = NULL, *next;
krb5_error_code code = 0;
- /*
- * First off, build a query of the form:
- *
- * service.protocol.realm
- *
- * which will most likely be something like:
- *
- * _kerberos._udp.REALM
- *
- */
-
- if ( strlen(service) + strlen(protocol) + realm->length + 6
- > MAX_DNS_NAMELEN )
- goto out;
- sprintf(host, "%s.%s.%.*s", service, protocol, (int) realm->length,
- realm->data);
-
- /* Realm names don't (normally) end with ".", but if the query
- doesn't end with "." and doesn't get an answer as is, the
- resolv code will try appending the local domain. Since the
- realm names are absolutes, let's stop that.
-
- But only if a name has been specified. If we are performing
- a search on the prefix alone then the intention is to allow
- the local domain or domain search lists to be expanded. */
-
- h = host + strlen (host);
- if ((h > host) && (h[-1] != '.') && ((h - host + 1) < sizeof(host)))
- strcpy (h, ".");
-
-#ifdef TEST
- fprintf (stderr, "sending DNS SRV query for %s\n", host);
-#endif
-
- size = res_search(host, C_IN, T_SRV, answer.bytes, sizeof(answer.bytes));
-
- if ((size < hdrsize) || (size > sizeof(answer.bytes)))
- goto out;
-
- /*
- * We got an answer! First off, parse the header and figure out how
- * many answers we got back.
- */
-
- p = answer.bytes;
-
- numqueries = ntohs(answer.hdr.qdcount);
- numanswers = ntohs(answer.hdr.ancount);
-
- p += sizeof(HEADER);
-
- /*
- * We need to skip over all of the questions, so we have to iterate
- * over every query record. dn_expand() is able to tell us the size
- * of compress DNS names, so we use it.
- */
-
-#define INCR_CHECK(x,y) x += y; if (x > size + answer.bytes) goto out
-#define CHECK(x,y) if (x + y > size + answer.bytes) goto out
-#define NTOHSP(x,y) x[0] << 8 | x[1]; x += y
-
- while (numqueries--) {
- len = dn_expand(answer.bytes, answer.bytes + size, p, host, sizeof(host));
- if (len < 0)
- goto out;
- INCR_CHECK(p, len + 4);
- }
-
- /*
- * We're now pointing at the answer records. Only process them if
- * they're actually T_SRV records (they might be CNAME records,
- * for instance).
- *
- * But in a DNS reply, if you get a CNAME you always get the associated
- * "real" RR for that CNAME. RFC 1034, 3.6.2:
- *
- * CNAME RRs cause special action in DNS software. When a name server
- * fails to find a desired RR in the resource set associated with the
- * domain name, it checks to see if the resource set consists of a CNAME
- * record with a matching class. If so, the name server includes the CNAME
- * record in the response and restarts the query at the domain name
- * specified in the data field of the CNAME record. The one exception to
- * this rule is that queries which match the CNAME type are not restarted.
- *
- * In other words, CNAMEs do not need to be expanded by the client.
- */
-
- while (numanswers--) {
-
- /* First is the name; use dn_expand to get the compressed size */
- len = dn_expand(answer.bytes, answer.bytes + size, p, host, sizeof(host));
- if (len < 0)
- goto out;
- INCR_CHECK(p, len);
-
- /* Next is the query type */
- CHECK(p, 2);
- type = NTOHSP(p,2);
-
- /* Next is the query class; also skip over 4 byte TTL */
- CHECK(p, 6);
- rrclass = NTOHSP(p,6);
-
- /* Record data length */
-
- CHECK(p,2);
- rdlen = NTOHSP(p,2);
-
- /*
- * If this is an SRV record, process it. Record format is:
- *
- * Priority
- * Weight
- * Port
- * Server name
- */
+ code = krb5int_make_srv_query_realm(realm, service, protocol, &head);
+ if (code)
+ return 0;
- if (rrclass == C_IN && type == T_SRV) {
- CHECK(p,2);
- priority = NTOHSP(p,2);
- CHECK(p, 2);
- weight = NTOHSP(p,2);
- CHECK(p, 2);
- port = NTOHSP(p,2);
- len = dn_expand(answer.bytes, answer.bytes + size, p, host, sizeof(host));
- if (len < 0)
- goto out;
- INCR_CHECK(p, len);
-
- /*
- * We got everything! Insert it into our list, but make sure
- * it's in the right order. Right now we don't do anything
- * with the weight field
- */
-
- srv = (struct srv_dns_entry *) malloc(sizeof(struct srv_dns_entry));
- if (srv == NULL)
- goto out;
-
- srv->priority = priority;
- srv->weight = weight;
- srv->port = port;
- srv->host = strdup(host);
-
- if (head == NULL || head->priority > srv->priority) {
- srv->next = head;
- head = srv;
- } else
- /*
- * This is confusing. Only insert an entry into this
- * spot if:
- * The next person has a higher priority (lower priorities
- * are preferred).
- * Or
- * There is no next entry (we're at the end)
- */
- for (entry = head; entry != NULL; entry = entry->next)
- if ((entry->next &&
- entry->next->priority > srv->priority) ||
- entry->next == NULL) {
- srv->next = entry->next;
- entry->next = srv;
- break;
- }
- } else
- INCR_CHECK(p, rdlen);
- }
-
/*
* Okay! Now we've got a linked list of entries sorted by
* priority. Start looking up A records and returning
@@ -712,53 +524,44 @@ krb5_locate_srv_dns_1 (const krb5_data *realm,
*/
if (head == NULL)
- goto out;
+ return 0;
+
+ /* Check for the "." case indicating no support. */
+ if (head->next == 0 && head->host[0] == 0) {
+ free(head->host);
+ free(head);
+ return KRB5_ERR_NO_SERVICE;
+ }
#ifdef TEST
fprintf (stderr, "walking answer list:\n");
#endif
- for (entry = head; entry != NULL; entry = entry->next) {
+ for (entry = head; entry != NULL; entry = next) {
#ifdef TEST
fprintf (stderr, "\tport=%d host=%s\n", entry->port, entry->host);
#endif
+ next = entry->next;
code = add_host_to_list (addrlist, entry->host, htons (entry->port), 0,
(strcmp("_tcp", protocol)
? SOCK_DGRAM
: SOCK_STREAM), family);
if (code)
break;
+ if (entry == head) {
+ free(entry->host);
+ free(entry);
+ head = next;
+ entry = 0;
+ }
}
#ifdef TEST
fprintf (stderr, "[end]\n");
#endif
- for (entry = head; entry != NULL; ) {
- free(entry->host);
- entry->host = NULL;
- srv = entry;
- entry = entry->next;
- free(srv);
- srv = NULL;
- }
-
- out:
- if (srv)
- free(srv);
-
+ krb5int_free_srv_dns_data(head);
return code;
}
-#ifdef TEST
-static krb5_error_code
-krb5_locate_srv_dns(const krb5_data *realm,
- const char *service, const char *protocol,
- struct addrlist *al)
-{
- return krb5_locate_srv_dns_1 (realm, service, protocol, al, 0);
-}
-#endif
-#endif /* KRB5_DNS_LOOKUP */
-
/*
* Wrapper function for the two backends
*/
@@ -852,7 +655,8 @@ krb5_locate_kdc(krb5_context context, const krb5_data *realm,
sec_udpport = 0;
}
- return krb5int_locate_server(context, realm, addrlist, get_masters, "kdc",
+ return krb5int_locate_server(context, realm, addrlist, 0,
+ get_masters ? "master_kdc" : "kdc",
(get_masters
? "_kerberos-master"
: "_kerberos"),
generated by cgit v1.1 at 2024-08-01 10:08:47 +0000