Kerberos credentials may be stored in multiple places. Make it

possible to search several directories for valid credentials when
making NFS requests.

Original patch from Vince Busam <vbusam@google.com>

Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>.
Signed-off-by: Steve Dickson <steved@redhat.com>

6 files changed, 43 insertions, 20 deletions

diff --git a/utils/gssd/gssd.c b/utils/gssd/gssd.c
index bbcad20..e8612a5 100644
--- a/utils/gssd/gssd.c
+++ b/utils/gssd/gssd.c
@@ -57,6 +57,7 @@ char pipefs_dir[PATH_MAX] = GSSD_PIPEFS_DIR;
 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 + 1];
 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':
@@ -136,6 +139,13 @@ main(int argc, char *argv[])
 				break;
 		}
 	}
+
+	i = 0;
+	ccachesearch[i++] = strtok(ccachedir, ":");
+	do {
+		ccachesearch[i++] = strtok(NULL, ":");
+	} while (ccachesearch[i-1] != NULL && i < GSSD_MAX_CCACHE_SEARCH);
+
 	snprintf(pipefs_nfsdir, sizeof(pipefs_nfsdir), "%s/%s",
 		 pipefs_dir, GSSD_SERVICE_NAME);
 	if (pipefs_nfsdir[sizeof(pipefs_nfsdir)-1] != '\0')
diff --git a/utils/gssd/gssd.h b/utils/gssd/gssd.h
index 6f14c34..0f9f428 100644
--- a/utils/gssd/gssd.h
+++ b/utils/gssd/gssd.h
@@ -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
@@ -61,7 +62,7 @@ enum {AUTHTYPE_KRB5, AUTHTYPE_SPKM3, AUTHTYPE_LIPKEY};
 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[];
 extern int			use_memcache;
 extern int			root_uses_machine_creds;
 
diff --git a/utils/gssd/gssd.man b/utils/gssd/gssd.man
index 2fa749e..8fa4f4a 100644
--- a/utils/gssd/gssd.man
+++ b/utils/gssd/gssd.man
@@ -74,7 +74,11 @@ where to look for the rpc_pipefs filesystem.  The default value is
 .B -d directory
 Tells
 .B rpc.gssd
-where to look for kerberos credential files.  The default value is "/tmp".
+where to look for Kerberos credential files.  The default value is "/tmp".
+This can also be a colon separated list of directories to be searched
+for Kerberos credential files.  Note that if machine credentials are being
+stored in files, then the first directory on this list is where the
+machine credentials are stored.
 .TP
 .B -v
 Increases the verbosity of the output (can be specified multiple times).
diff --git a/utils/gssd/gssd_proc.c b/utils/gssd/gssd_proc.c
index bac7295..be6f440 100644
--- a/utils/gssd/gssd_proc.c
+++ b/utils/gssd/gssd_proc.c
@@ -685,6 +685,7 @@ handle_krb5_upcall(struct clnt_info *clp)
 	gss_buffer_desc		token;
 	char			**credlist = NULL;
 	char			**ccname;
+	char			**dirname;
 	int			create_resp = -1;
 
 	printerr(1, "handling krb5 upcall\n");
@@ -701,10 +702,14 @@ 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);
+		for (dirname = ccachesearch; *dirname != NULL; dirname++) {
+			gssd_setup_krb5_user_gss_ccache(uid, clp->servername, *dirname);
 
-		create_resp = create_auth_rpc_client(clp, &rpc_clnt, &auth, uid,
-						     AUTHTYPE_KRB5);
+			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 --git a/utils/gssd/krb5_util.c b/utils/gssd/krb5_util.c
index 0589cd8..512c1cf 100644
--- a/utils/gssd/krb5_util.c
+++ b/utils/gssd/krb5_util.c
@@ -131,7 +131,8 @@ struct gssd_k5_kt_princ *gssd_k5_kt_princ_list = NULL;
 /*==========================*/
 
 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, char *dirname,
+		struct dirent **d);
 static int gssd_get_single_krb5_cred(krb5_context context,
 		krb5_keytab kt, struct gssd_k5_kt_princ *ple);
 
@@ -159,7 +160,7 @@ select_krb5_ccache(const struct dirent *d)
 }
 
 /*
- * Look in the ccachedir for files that look like they
+ * Look in directory "dirname" for files that look like they
  * are Kerberos Credential Cache files for a given UID.  Return
  * non-zero and the dirent pointer for the entry most likely to be
  * what we want. Otherwise, return zero and no dirent pointer.
@@ -170,7 +171,7 @@ select_krb5_ccache(const struct dirent *d)
  *	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, char *dirname, struct dirent **d)
 {
 	struct dirent **namelist;
 	int n;
@@ -181,9 +182,10 @@ gssd_find_existing_krb5_ccache(uid_t uid, struct dirent **d)
 
 	memset(&best_match_stat, 0, sizeof(best_match_stat));
 	*d = NULL;
-	n = scandir(ccachedir, &namelist, select_krb5_ccache, 0);
+	n = scandir(dirname, &namelist, select_krb5_ccache, 0);
 	if (n < 0) {
-		perror("scandir looking for krb5 credentials caches");
+		printerr(1, "Error doing scandir on directory '%s': %s\n",
+			dirname, strerror(errno));
 	}
 	else if (n > 0) {
 		char statname[1024];
@@ -191,7 +193,7 @@ gssd_find_existing_krb5_ccache(uid_t uid, struct dirent **d)
 			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", dirname, namelist[i]->d_name);
 			if (lstat(statname, &tmp_stat)) {
 				printerr(0, "Error doing stat on file '%s'\n",
 					 statname);
@@ -291,8 +293,9 @@ limit_krb5_enctypes(struct rpc_gss_sec *sec, uid_t uid)
 				    &credh, NULL, NULL);
 
 	if (maj_stat != GSS_S_COMPLETE) {
-		pgsserr("gss_acquire_cred",
-			maj_stat, min_stat, &krb5oid);
+		if (get_verbosity() > 0)
+			pgsserr("gss_acquire_cred",
+				maj_stat, min_stat, &krb5oid);
 		return -1;
 	}
 
@@ -406,7 +409,7 @@ gssd_get_single_krb5_cred(krb5_context context,
 	    cache_type = "FILE";
 	snprintf(cc_name, sizeof(cc_name), "%s:%s/%s%s_%s",
 		cache_type,
-		ccachedir, GSSD_DEFAULT_CRED_PREFIX,
+		ccachesearch[0], GSSD_DEFAULT_CRED_PREFIX,
 		GSSD_DEFAULT_MACHINE_CRED_SUFFIX, ple->realm);
 	ple->endtime = my_creds.times.endtime;
 	if (ple->ccname != NULL)
@@ -894,7 +897,7 @@ 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 *dirname)
 {
 	char			buf[MAX_NETOBJ_SZ];
 	struct dirent		*d;
@@ -902,14 +905,13 @@ gssd_setup_krb5_user_gss_ccache(uid_t uid, char *servername)
 	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)) {
-		snprintf(buf, sizeof(buf), "FILE:%s/%s",
-			ccachedir, d->d_name);
+	if (gssd_find_existing_krb5_ccache(uid, dirname, &d)) {
+		snprintf(buf, sizeof(buf), "FILE:%s/%s", dirname, d->d_name);
 		free(d);
 	}
 	else
 		snprintf(buf, sizeof(buf), "FILE:%s/%s%u",
-			ccachedir, GSSD_DEFAULT_CRED_PREFIX, uid);
+			dirname, 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 --git a/utils/gssd/krb5_util.h b/utils/gssd/krb5_util.h
index 78ad45c..431fdaf 100644
--- a/utils/gssd/krb5_util.h
+++ b/utils/gssd/krb5_util.h
@@ -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 *dirname);
 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);