2008-04-07 21:42:26

by Vince Busam

[permalink] [raw]
Subject: [PATCH] gssd: search multiple directories for credentials

We store kerberos credentials in multiple places, and it would be nice to
search them for a valid credential when making NFS requests. This patch
allows that.

diff -up --recursive nfs-utils-1.1.1.orig/utils/gssd/gssd.c nfs-utils-1.1.1/utils/gssd/gssd.c
--- nfs-utils-1.1.1.orig/utils/gssd/gssd.c 2007-10-18 20:07:28.000000000 -0700
+++ nfs-utils-1.1.1/utils/gssd/gssd.c 2008-03-17 13:35:39.000000000 -0700
@@ -57,6 +57,7 @@ char pipefs_dir[PATH_MAX] = GSSD_PIPEFS_
char pipefs_nfsdir[PATH_MAX] = GSSD_PIPEFS_DIR;
char keytabfile[PATH_MAX] = GSSD_DEFAULT_KEYTAB_FILE;
char ccachedir[PATH_MAX] = GSSD_DEFAULT_CRED_DIR;
+char *ccachesearch[GSSD_MAX_CCACHE_SEARCH];
int use_memcache = 0;
int root_uses_machine_creds = 1;

@@ -93,9 +94,11 @@ main(int argc, char *argv[])
int verbosity = 0;
int rpc_verbosity = 0;
int opt;
+ int i;
extern char *optarg;
char *progname;

+ memset(ccachesearch, 0, sizeof(ccachesearch));
while ((opt = getopt(argc, argv, "fvrmnMp:k:d:")) != -1) {
switch (opt) {
case 'f':
@@ -130,6 +133,12 @@ main(int argc, char *argv[])
strncpy(ccachedir, optarg, sizeof(ccachedir));
if (ccachedir[sizeof(ccachedir)-1] != '\0')
errx(1, "ccachedir path name too long");
+ i = 0;
+ strtok(ccachedir,":");
+ do {
+ ccachesearch[i] = strtok(NULL,":");
+ i++;
+ } while (ccachesearch[i-1] && (i<(GSSD_MAX_CCACHE_SEARCH-1)));
break;
default:
usage(argv[0]);
diff -up --recursive nfs-utils-1.1.1.orig/utils/gssd/gssd.h nfs-utils-1.1.1/utils/gssd/gssd.h
--- nfs-utils-1.1.1.orig/utils/gssd/gssd.h 2007-10-18 20:07:28.000000000 -0700
+++ nfs-utils-1.1.1/utils/gssd/gssd.h 2008-03-12 13:10:19.000000000 -0700
@@ -50,6 +50,7 @@
#define GSSD_DEFAULT_KEYTAB_FILE "/etc/krb5.keytab"
#define GSSD_SERVICE_NAME "nfs"
#define GSSD_SERVICE_NAME_LEN 3
+#define GSSD_MAX_CCACHE_SEARCH 16

/*
* The gss mechanisms that we can handle
@@ -62,6 +63,7 @@ extern char pipefs_dir[PATH_MAX];
extern char pipefs_nfsdir[PATH_MAX];
extern char keytabfile[PATH_MAX];
extern char ccachedir[PATH_MAX];
+extern char *ccachesearch[GSSD_MAX_CCACHE_SEARCH];
extern int use_memcache;
extern int root_uses_machine_creds;

diff -up --recursive nfs-utils-1.1.1.orig/utils/gssd/gssd.man nfs-utils-1.1.1/utils/gssd/gssd.man
--- nfs-utils-1.1.1.orig/utils/gssd/gssd.man 2007-10-18 20:07:28.000000000 -0700
+++ nfs-utils-1.1.1/utils/gssd/gssd.man 2008-03-12 13:10:19.000000000 -0700
@@ -75,6 +75,8 @@ where to look for the rpc_pipefs filesys
Tells
.B rpc.gssd
where to look for kerberos credential files. The default value is "/tmp".
+This can also be a colon separated list of directories to search through
+for a kerberos credential file.
.TP
.B -v
Increases the verbosity of the output (can be specified multiple times).
diff -up --recursive nfs-utils-1.1.1.orig/utils/gssd/gssd_proc.c nfs-utils-1.1.1/utils/gssd/gssd_proc.c
--- nfs-utils-1.1.1.orig/utils/gssd/gssd_proc.c 2007-10-18 20:07:28.000000000 -0700
+++ nfs-utils-1.1.1/utils/gssd/gssd_proc.c 2008-03-12 14:44:26.000000000 -0700
@@ -691,10 +691,18 @@ handle_krb5_upcall(struct clnt_info *clp

if (uid != 0 || (uid == 0 && root_uses_machine_creds == 0)) {
/* Tell krb5 gss which credentials cache to use */
- gssd_setup_krb5_user_gss_ccache(uid, clp->servername);
+ gssd_setup_krb5_user_gss_ccache(uid, clp->servername, ccachedir);

create_resp = create_auth_rpc_client(clp, &rpc_clnt, &auth, uid,
AUTHTYPE_KRB5);
+ for (ccname = ccachesearch; *ccname; ccname++) {
+ gssd_setup_krb5_user_gss_ccache(uid, clp->servername, *ccname);
+
+ create_resp = create_auth_rpc_client(clp, &rpc_clnt, &auth, uid,
+ AUTHTYPE_KRB5);
+ if (create_resp == 0)
+ break;
+ }
}
if (create_resp != 0) {
if (uid == 0 && root_uses_machine_creds == 1) {
diff -up --recursive nfs-utils-1.1.1.orig/utils/gssd/krb5_util.c nfs-utils-1.1.1/utils/gssd/krb5_util.c
--- nfs-utils-1.1.1.orig/utils/gssd/krb5_util.c 2007-10-18 20:07:28.000000000 -0700
+++ nfs-utils-1.1.1/utils/gssd/krb5_util.c 2008-03-12 13:10:19.000000000 -0700
@@ -131,7 +131,8 @@ struct gssd_k5_kt_princ *gssd_k5_kt_prin
/*==========================*/

static int select_krb5_ccache(const struct dirent *d);
-static int gssd_find_existing_krb5_ccache(uid_t uid, struct dirent **d);
+static int gssd_find_existing_krb5_ccache(uid_t uid, struct dirent **d,
+ char *directory);
static int gssd_get_single_krb5_cred(krb5_context context,
krb5_keytab kt, struct gssd_k5_kt_princ *ple);

@@ -170,7 +171,7 @@ select_krb5_ccache(const struct dirent *
* 1 => found an existing entry
*/
static int
-gssd_find_existing_krb5_ccache(uid_t uid, struct dirent **d)
+gssd_find_existing_krb5_ccache(uid_t uid, struct dirent **d, char *directory)
{
struct dirent **namelist;
int n;
@@ -181,7 +182,7 @@ gssd_find_existing_krb5_ccache(uid_t uid

memset(&best_match_stat, 0, sizeof(best_match_stat));
*d = NULL;
- n = scandir(ccachedir, &namelist, select_krb5_ccache, 0);
+ n = scandir(directory, &namelist, select_krb5_ccache, 0);
if (n < 0) {
perror("scandir looking for krb5 credentials caches");
}
@@ -191,7 +192,7 @@ gssd_find_existing_krb5_ccache(uid_t uid
printerr(3, "CC file '%s' being considered\n",
namelist[i]->d_name);
snprintf(statname, sizeof(statname),
- "%s/%s", ccachedir, namelist[i]->d_name);
+ "%s/%s", directory, namelist[i]->d_name);
if (lstat(statname, &tmp_stat)) {
printerr(0, "Error doing stat on file '%s'\n",
statname);
@@ -892,7 +893,7 @@ out:
* void
*/
void
-gssd_setup_krb5_user_gss_ccache(uid_t uid, char *servername)
+gssd_setup_krb5_user_gss_ccache(uid_t uid, char *servername, char *directory)
{
char buf[MAX_NETOBJ_SZ];
struct dirent *d;
@@ -900,14 +901,14 @@ gssd_setup_krb5_user_gss_ccache(uid_t ui
printerr(2, "getting credentials for client with uid %u for "
"server %s\n", uid, servername);
memset(buf, 0, sizeof(buf));
- if (gssd_find_existing_krb5_ccache(uid, &d)) {
+ if (gssd_find_existing_krb5_ccache(uid, &d, directory)) {
snprintf(buf, sizeof(buf), "FILE:%s/%s",
- ccachedir, d->d_name);
+ directory, d->d_name);
free(d);
}
else
snprintf(buf, sizeof(buf), "FILE:%s/%s%u",
- ccachedir, GSSD_DEFAULT_CRED_PREFIX, uid);
+ directory, GSSD_DEFAULT_CRED_PREFIX, uid);
printerr(2, "using %s as credentials cache for client with "
"uid %u for server %s\n", buf, uid, servername);
gssd_set_krb5_ccache_name(buf);
diff -up --recursive nfs-utils-1.1.1.orig/utils/gssd/krb5_util.h nfs-utils-1.1.1/utils/gssd/krb5_util.h
--- nfs-utils-1.1.1.orig/utils/gssd/krb5_util.h 2007-10-18 20:07:28.000000000 -0700
+++ nfs-utils-1.1.1/utils/gssd/krb5_util.h 2008-03-12 13:10:19.000000000 -0700
@@ -17,7 +17,8 @@ struct gssd_k5_kt_princ {
};


-void gssd_setup_krb5_user_gss_ccache(uid_t uid, char *servername);
+void gssd_setup_krb5_user_gss_ccache(uid_t uid, char *servername,
+ char *directory);
int gssd_get_krb5_machine_cred_list(char ***list);
void gssd_free_krb5_machine_cred_list(char **list);
void gssd_setup_krb5_machine_gss_ccache(char *servername);


2008-04-08 17:15:09

by Kevin Coffman

[permalink] [raw]
Subject: Re: [PATCH] gssd: search multiple directories for credentials

On Mon, Apr 7, 2008 at 5:42 PM, Vince Busam <[email protected]> wrote:
> We store kerberos credentials in multiple places, and it would be nice to
> search them for a valid credential when making NFS requests. This patch
> allows that.
>
> diff -up --recursive nfs-utils-1.1.1.orig/utils/gssd/gssd.c nfs-utils-1.1.1/utils/gssd/gssd.c
> --- nfs-utils-1.1.1.orig/utils/gssd/gssd.c 2007-10-18 20:07:28.000000000 -0700
> +++ nfs-utils-1.1.1/utils/gssd/gssd.c 2008-03-17 13:35:39.000000000 -0700
> @@ -57,6 +57,7 @@ char pipefs_dir[PATH_MAX] = GSSD_PIPEFS_
> char pipefs_nfsdir[PATH_MAX] = GSSD_PIPEFS_DIR;
> char keytabfile[PATH_MAX] = GSSD_DEFAULT_KEYTAB_FILE;
> char ccachedir[PATH_MAX] = GSSD_DEFAULT_CRED_DIR;
> +char *ccachesearch[GSSD_MAX_CCACHE_SEARCH];
> int use_memcache = 0;
> int root_uses_machine_creds = 1;
>
> @@ -93,9 +94,11 @@ main(int argc, char *argv[])
> int verbosity = 0;
> int rpc_verbosity = 0;
> int opt;
> + int i;
> extern char *optarg;
> char *progname;
>
> + memset(ccachesearch, 0, sizeof(ccachesearch));
> while ((opt = getopt(argc, argv, "fvrmnMp:k:d:")) != -1) {
> switch (opt) {
> case 'f':
> @@ -130,6 +133,12 @@ main(int argc, char *argv[])
> strncpy(ccachedir, optarg, sizeof(ccachedir));
> if (ccachedir[sizeof(ccachedir)-1] != '\0')
> errx(1, "ccachedir path name too long");
> + i = 0;
> + strtok(ccachedir,":");
> + do {
> + ccachesearch[i] = strtok(NULL,":");
> + i++;
> + } while (ccachesearch[i-1] && (i<(GSSD_MAX_CCACHE_SEARCH-1)));
> break;
> default:
> usage(argv[0]);
> diff -up --recursive nfs-utils-1.1.1.orig/utils/gssd/gssd.h nfs-utils-1.1.1/utils/gssd/gssd.h
> --- nfs-utils-1.1.1.orig/utils/gssd/gssd.h 2007-10-18 20:07:28.000000000 -0700
> +++ nfs-utils-1.1.1/utils/gssd/gssd.h 2008-03-12 13:10:19.000000000 -0700
> @@ -50,6 +50,7 @@
> #define GSSD_DEFAULT_KEYTAB_FILE "/etc/krb5.keytab"
> #define GSSD_SERVICE_NAME "nfs"
> #define GSSD_SERVICE_NAME_LEN 3
> +#define GSSD_MAX_CCACHE_SEARCH 16
>
> /*
> * The gss mechanisms that we can handle
> @@ -62,6 +63,7 @@ extern char pipefs_dir[PATH_MAX];
> extern char pipefs_nfsdir[PATH_MAX];
> extern char keytabfile[PATH_MAX];
> extern char ccachedir[PATH_MAX];
> +extern char *ccachesearch[GSSD_MAX_CCACHE_SEARCH];
> extern int use_memcache;
> extern int root_uses_machine_creds;
>
> diff -up --recursive nfs-utils-1.1.1.orig/utils/gssd/gssd_proc.c nfs-utils-1.1.1/utils/gssd/gssd_proc.c
> --- nfs-utils-1.1.1.orig/utils/gssd/gssd_proc.c 2007-10-18 20:07:28.000000000 -0700
> +++ nfs-utils-1.1.1/utils/gssd/gssd_proc.c 2008-03-12 14:44:26.000000000 -0700
> @@ -691,10 +691,18 @@ handle_krb5_upcall(struct clnt_info *clp
>
> if (uid != 0 || (uid == 0 && root_uses_machine_creds == 0)) {
> /* Tell krb5 gss which credentials cache to use */
> - gssd_setup_krb5_user_gss_ccache(uid, clp->servername);
> + gssd_setup_krb5_user_gss_ccache(uid, clp->servername, ccachedir);
>
> create_resp = create_auth_rpc_client(clp, &rpc_clnt, &auth, uid,
> AUTHTYPE_KRB5);
> + for (ccname = ccachesearch; *ccname; ccname++) {
> + gssd_setup_krb5_user_gss_ccache(uid, clp->servername, *ccname);
> +
> + create_resp = create_auth_rpc_client(clp, &rpc_clnt, &auth, uid,
> + AUTHTYPE_KRB5);
> + if (create_resp == 0)
> + break;
> + }
> }

Thanks for the patch, and sorry for taking so long to get to it.

If I use "-d /tmp:/tmp/ticket:/tmp/tickets", this part ignores the
fact that I've successfully created the context with credentials in
/tmp and continues to try /tmp/ticket and /tmp/tickets and eventually
fails.

I think I see why you continued to use ccachedir as well as
ccachesearch, but I'm not happy with it. I'm reworking this and will
submit upstream.

K.C.