Fix a crash bug when s4u2proxy is configured

If no cred store options are present at all the code now crashes trying
to access the structure that should hold the options as it is NULL.

Also add ifdefs that were missed in the original patch.

Signed-off-by: Simo Sorce <[email protected]>

Author: simo5

src/mod_auth_gssapi.c

@@ -714,8 +714,9 @@ void mag_verify_config(request_rec *req, struct mag_config *cfg)
     /* we check only once */
     if (cfg->verified) return;
 
+#ifdef HAVE_CRED_STORE
     /* Check if cred store config is consistent with use_s4u2proxy.
-     * Although not strictly required it is generally adivsable to
+     * Although not strictly required it is generally advisable to
      * set keytab, client_keytab, and ccache in the cred_store when
      * use_s4u2proxy is set, this is to avoid easy mistakes that are
      * very difficult to diagnose */
@@ -724,14 +725,16 @@ void mag_verify_config(request_rec *req, struct mag_config *cfg)
         bool has_client_keytab = false;
         bool has_ccache = false;
 
-        for (int i = 0; i < cfg->cred_store->count; i++) {
-            const char *key = cfg->cred_store->elements[i].key;
-            if (strcmp(key, "keytab") == 0) {
-                has_keytab = true;
-            } else if (strcmp(key, "client_keytab") == 0) {
-                has_client_keytab = true;
-            } else if (strcmp(key, "ccache") == 0) {
-                has_ccache = true;
+        if (cfg->cred_store) {
+            for (int i = 0; i < cfg->cred_store->count; i++) {
+                const char *key = cfg->cred_store->elements[i].key;
+                if (strcmp(key, "keytab") == 0) {
+                    has_keytab = true;
+                } else if (strcmp(key, "client_keytab") == 0) {
+                    has_client_keytab = true;
+                } else if (strcmp(key, "ccache") == 0) {
+                    has_ccache = true;
+                }
             }
         }
 
@@ -751,6 +754,7 @@ void mag_verify_config(request_rec *req, struct mag_config *cfg)
                           "GssapiCredStore", "ccache");
         }
     }
+#endif
 
     cfg->verified = true;
 }