Acquire creds only once for basic_auth

Instead of acquiring creds by looping at each round, use
gss_inquire_cred_by_mech() to work around the union_name issue and
get the correct per-mechanism server name.

Closes #45

Signed-off-by: Simo Sorce <simo@redhat.com>

Author: simo5

src/mod_auth_gssapi.c

@@ -402,12 +402,12 @@ static bool mag_auth_basic(request_rec *req,
     gss_name_t server = GSS_C_NO_NAME;
     gss_cred_id_t server_cred = GSS_C_NO_CREDENTIAL;
     gss_ctx_id_t server_ctx = GSS_C_NO_CONTEXT;
+    gss_cred_id_t acquired_cred = GSS_C_NO_CREDENTIAL;
     gss_buffer_desc input = GSS_C_EMPTY_BUFFER;
     gss_buffer_desc output = GSS_C_EMPTY_BUFFER;
     gss_OID_set indicated_mechs = GSS_C_NO_OID_SET;
     gss_OID_set allowed_mechs;
     gss_OID_set filtered_mechs;
-    gss_OID_set_desc all_mechs_desc;
     gss_OID_set actual_mechs = GSS_C_NO_OID_SET;
     uint32_t init_flags = 0;
     uint32_t maj, min;
@@ -524,6 +524,22 @@ static bool mag_auth_basic(request_rec *req,
         goto done;
     }
 
+    /* must acquire creds based on the actual mechs we want to try */
+    if (!mag_acquire_creds(req, cfg, actual_mechs,
+                           GSS_C_BOTH, &acquired_cred, NULL)) {
+        goto done;
+    }
+
+    if (cred_usage == GSS_C_BOTH) {
+        /* must acquire with GSS_C_ACCEPT to get the server name */
+        if (!mag_acquire_creds(req, cfg, actual_mechs,
+                               GSS_C_ACCEPT, &server_cred, NULL)) {
+            goto done;
+        }
+    } else {
+        server_cred = acquired_cred;
+    }
+
 #ifdef HAVE_CRED_STORE
     if (cfg->deleg_ccache_dir) {
         /* delegate ourselves credentials so we store them as requested */
@@ -543,35 +559,17 @@ static bool mag_auth_basic(request_rec *req,
         gss_release_buffer(&min, &output);
         gss_release_buffer(&min, &input);
         gss_release_name(&min, &server);
-        gss_release_cred(&min, &server_cred);
 
-        all_mechs_desc.count = 1;
-        all_mechs_desc.elements = &actual_mechs->elements[i];
-        allowed_mechs = &all_mechs_desc;
-
-        /* must acquire with GSS_C_ACCEPT to get the server name */
-        if (!mag_acquire_creds(req, cfg, allowed_mechs,
-                               GSS_C_ACCEPT, &server_cred, NULL)) {
-            continue;
-        }
-        maj = gss_inquire_cred(&min, server_cred, &server,
-                               NULL, NULL, NULL);
+        maj = gss_inquire_cred_by_mech(&min, server_cred,
+                                       &actual_mechs->elements[i],
+                                       &server, NULL, NULL, NULL);
         if (GSS_ERROR(maj)) {
             ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, req,
-                          "%s", mag_error(req, "gss_inquired_cred_() "
+                          "%s", mag_error(req, "gss_inquired_cred_by_mech() "
                                           "failed", maj, min));
             continue;
         }
 
-        if (cred_usage == GSS_C_BOTH) {
-            /* reacquire server creds in order to allow delegation */
-            gss_release_cred(&min, &server_cred);
-            if (!mag_acquire_creds(req, cfg, allowed_mechs,
-                                   GSS_C_BOTH, &server_cred, NULL)) {
-                continue;
-            }
-        }
-
         do {
             /* output and input are inverted here, this is intentional */
             maj = gss_init_sec_context(&min, user_cred, &user_ctx, server,
@@ -585,7 +583,7 @@ static bool mag_auth_basic(request_rec *req,
                 break;
             }
             gss_release_buffer(&min, &output);
-            maj = gss_accept_sec_context(&min, &server_ctx, server_cred,
+            maj = gss_accept_sec_context(&min, &server_ctx, acquired_cred,
                                          &input, GSS_C_NO_CHANNEL_BINDINGS,
                                          client, mech_type, &output, NULL,
                                          vtime, delegated_cred);
@@ -608,8 +606,10 @@ static bool mag_auth_basic(request_rec *req,
     gss_release_buffer(&min, &output);
     gss_release_buffer(&min, &input);
     gss_release_name(&min, &server);
-    gss_release_cred(&min, &server_cred);
+    if (server_cred != acquired_cred)
+        gss_release_cred(&min, &server_cred);
     gss_delete_sec_context(&min, &server_ctx, GSS_C_NO_BUFFER);
+    gss_release_cred(&min, &acquired_cred);
     gss_release_name(&min, &user);
     gss_release_cred(&min, &user_cred);
     gss_delete_sec_context(&min, &user_ctx, GSS_C_NO_BUFFER);
@@ -834,6 +834,7 @@ static int mag_auth(request_rec *req)
         cred_usage = GSS_C_BOTH;
     }
 #endif
+
     if (auth_type == AUTH_TYPE_BASIC) {
         if (mag_auth_basic(req, cfg, ba_user, ba_pwd,
                            cred_usage, &client, &mech_type,