A NFS client should be able to work properly even if the DNS Reverse record
for the server is not set. There is no excuse to forcefully prevent that
from working when it can.
This patch adds a new pair of options (-z/-Z) that allow to turn on/off
DNS reverse resolution for determining the server name to use with GSSAPI.
To avoid breaking current behavior the option defaults to off by default,
ideally we will turn this on by default after a transition period.
Signed-off-by: Simo Sorce <simo@xxxxxxxxxx>
---
utils/gssd/gss_util.h | 2 ++
utils/gssd/gssd.c | 10 ++++++++--
utils/gssd/gssd_proc.c | 25 +++++++++++++++++++++----
3 files changed, 31 insertions(+), 6 deletions(-)
diff --git a/utils/gssd/gss_util.h b/utils/gssd/gss_util.h
index aa9f77806075f9ab67a7763a75a010369ba2d1b9..663fb0998bede6144118f890b9311ee8687176e3 100644
--- a/utils/gssd/gss_util.h
+++ b/utils/gssd/gss_util.h
@@ -52,4 +52,6 @@ int gssd_check_mechs(void);
gss_krb5_set_allowable_enctypes(min, cred, num, types)
#endif
+extern int avoid_ptr;
+
#endif /* _GSS_UTIL_H_ */
diff --git a/utils/gssd/gssd.c b/utils/gssd/gssd.c
index 07b1e52e6b84e9bcba96e7a63b0505ca7823482a..1f0ac0c47667c42ed03e271cb18b6124165e5d5f 100644
--- a/utils/gssd/gssd.c
+++ b/utils/gssd/gssd.c
@@ -85,7 +85,7 @@ sig_hup(int signal)
static void
usage(char *progname)
{
- fprintf(stderr, "usage: %s [-f] [-l] [-M] [-n] [-v] [-r] [-p pipefsdir] [-k keytab] [-d ccachedir] [-t timeout] [-R preferred realm]\n",
+ fprintf(stderr, "usage: %s [-f] [-l] [-M] [-n] [-v] [-r] [-p pipefsdir] [-k keytab] [-d ccachedir] [-t timeout] [-R preferred realm] [-z] [-Z]\n",
progname);
exit(1);
}
@@ -102,7 +102,7 @@ main(int argc, char *argv[])
char *progname;
memset(ccachesearch, 0, sizeof(ccachesearch));
- while ((opt = getopt(argc, argv, "fvrlmnMp:k:d:t:R:")) != -1) {
+ while ((opt = getopt(argc, argv, "fvrlmnMp:k:d:t:R:zZ")) != -1) {
switch (opt) {
case 'f':
fg = 1;
@@ -150,6 +150,12 @@ main(int argc, char *argv[])
errx(1, "Encryption type limits not supported by Kerberos libraries.");
#endif
break;
+ case 'z':
+ avoid_ptr = 1;
+ break;
+ case 'Z':
+ avoid_ptr = 0;
+ break;
default:
usage(argv[0]);
break;
diff --git a/utils/gssd/gssd_proc.c b/utils/gssd/gssd_proc.c
index ea01e92e4565670b97dea1a936d2f0dbdc7c4610..21d4e1d78eb54d177626cb0a19b9de4e93e0a20d 100644
--- a/utils/gssd/gssd_proc.c
+++ b/utils/gssd/gssd_proc.c
@@ -67,6 +67,7 @@
#include <errno.h>
#include <gssapi/gssapi.h>
#include <netdb.h>
+#include <ctype.h>
#include "gssd.h"
#include "err_util.h"
@@ -107,6 +108,8 @@ struct pollfd * pollarray;
unsigned long pollsize; /* the size of pollaray (in pollfd's) */
+int avoid_ptr = 0;
+
/*
* convert a presentation address string to a sockaddr_storage struct. Returns
* true on success or false on failure.
@@ -165,12 +168,26 @@ addrstr_to_sockaddr(struct sockaddr *sa, const char *node, const char *port)
* convert a sockaddr to a hostname
*/
static char *
-sockaddr_to_hostname(const struct sockaddr *sa, const char *addr)
+get_servername(const char *name, const struct sockaddr *sa, const char *addr)
{
socklen_t addrlen;
int err;
char *hostname;
char hbuf[NI_MAXHOST];
+ unsigned char buf[sizeof(struct in6_addr)];
+ int do_ptr_lookup = 0;
+
+ if (avoid_ptr) {
+ /* try to determine if this is a name, or an IP address.
+ * If it is an IP fallback to a PTR lookup */
+ if (strchr(name, '.') && inet_pton(AF_INET, name, buf) == 1)
+ do_ptr_lookup = 1; /* IPv4 */
+ else if (strchr(name, ':') && inet_pton(AF_INET6, name, buf) == 1)
+ do_ptr_lookup = 1; /* or IPv6 */
+ if (!do_ptr_lookup) {
+ return strdup(name);
+ }
+ }
switch (sa->sa_family) {
case AF_INET:
@@ -208,7 +225,7 @@ read_service_info(char *info_file_name, char **servicename, char **servername,
struct sockaddr *addr) {
#define INFOBUFLEN 256
char buf[INFOBUFLEN + 1];
- static char dummy[128];
+ static char server[128];
int nbytes;
static char service[128];
static char address[128];
@@ -236,7 +253,7 @@ read_service_info(char *info_file_name, char **servicename, char **servername,
"service: %127s %15s version %15s\n"
"address: %127s\n"
"protocol: %15s\n",
- dummy,
+ server,
service, program, version,
address,
protoname);
@@ -258,7 +275,7 @@ read_service_info(char *info_file_name, char **servicename, char **servername,
if (!addrstr_to_sockaddr(addr, address, port))
goto fail;
- *servername = sockaddr_to_hostname(addr, address);
+ *servername = get_servername(server, addr, address);
if (*servername == NULL)
goto fail;
--
1.7.1
--
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