Resolve the unqualified hostname and set AI_CANONNAME to make sure that
field is populated. Scan forward to the first '.' in ai_canonname, and
append that value onto the unqualified hostname to get a FQDN. Then
prepend that value with "cifs/" and try to get a service ticket for
that principal. If that fails prepend with "host/" and try again.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxx>
---
cifs.upcall.c | 50 ++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 44 insertions(+), 6 deletions(-)
diff --git a/cifs.upcall.c b/cifs.upcall.c
index 57ed0ba..ab3f87f 100644
--- a/cifs.upcall.c
+++ b/cifs.upcall.c
@@ -945,20 +945,58 @@ retry_new_hostname:
if (!rc)
break;
} else {
+ struct addrinfo hints;
+ struct addrinfo *ai;
+ char *domainname;
+
/* shortname: try AD-style first */
set_ad_principal(princ, host);
rc = handle_krb5_mech(oid, princ, &secblob, &sess_key, ccname);
if (!rc)
break;
+ /* Try to guess the DNS domain name for the host. We must */
+
/*
- * FIXME: try to guess the DNS domain name for the host. We
- * must require that the kernel sends the IP addr in the upcall.
- *
- * Use getaddrinfo() to resolve the hostname of the server and
- * set ai_canonname. Then use the domainname in ai canonname
- * to turn the unqualified hostname into a FQDN.
+ * use getaddrinfo() to resolve the hostname of the server
+ * and set ai_canonname.
*/
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = AF_UNSPEC;
+ hints.ai_flags = AI_CANONNAME;
+ rc = getaddrinfo(host, NULL, &hints, &ai);
+ if (rc) {
+ syslog(LOG_ERR, "Unable to resolve host address: %s [%s]",
+ host, gai_strerror(rc));
+ break;
+ }
+
+ /* scan forward to first '.' in ai_canonnname */
+ domainname = strchr(ai->ai_canonname, '.');
+ if (!domainname) {
+ rc = -EINVAL;
+ freeaddrinfo(ai);
+ break;
+ }
+
+ rc = snprintf(princ, sizeof(princ), "cifs/%s%s",
+ host, domainname);
+ freeaddrinfo(ai);
+ if (rc < 0 || (size_t)rc >= sizeof(princ)) {
+ syslog(LOG_ERR, "Problem setting hostname in string: %ld", rc);
+ rc = -EINVAL;
+ break;
+ }
+
+ rc = handle_krb5_mech(oid, princ, &secblob, &sess_key, ccname);
+ if (!rc)
+ break;
+
+ /* now try "host/" */
+ memcpy(princ, "host", 4);
+ rc = handle_krb5_mech(oid, princ, &secblob, &sess_key, ccname);
+ if (!rc)
+ break;
}
if (!try_dns || !(have & DKD_HAVE_IP))
--
1.7.6.4
--
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