From 06a53c87bf2870967ced8af0b32927dfbd7363ca Mon Sep 17 00:00:00 2001
From: Nirbheek Chauhan <nirbheek@centricular.com>
Date: Mon, 28 Jul 2014 12:38:56 +0530
Subject: server: Verify the UDP client list during token validation

---
 src/lib.c  | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.h  |  2 ++
 src/main.c | 10 ++++++++--
 3 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/src/lib.c b/src/lib.c
index cc36292..ec32660 100644
--- a/src/lib.c
+++ b/src/lib.c
@@ -88,6 +88,55 @@ stp_validate_token_server (GInetAddressMask  *mask,
   return ret;
 }
 
+gboolean stp_clients_is_subset (char *superset,
+                                char *subset)
+{
+  gsize i, n;
+  gboolean ret;
+  char **supersetv, **subsetv;
+  GHashTable *superset_table = NULL;
+
+  if (!subset)
+    return TRUE;
+
+  if (!superset)
+    return FALSE;
+
+  /* Simplest case */
+  if (g_strcmp0 (superset, subset) == 0)
+    return TRUE;
+
+  subsetv = g_strsplit (subset, ",", 0);
+  supersetv = g_strsplit (superset, ",", 0);
+
+  if (sizeof(supersetv)/sizeof(supersetv[0]) <= 1 ||
+      sizeof(subsetv)/sizeof(subsetv[0]) < 1)
+    /* If there's one client in the superset, and the subset didn't match,
+     * it won't match. Same if there's less than one client in either list. */
+    goto fail;
+
+  /* Easiest way to check. Add superset clients to a table, and then check
+   * whether every subset client is in that table. */
+  superset_table = g_hash_table_new (g_str_hash, g_str_equal);
+  for (i = 0, n = sizeof(supersetv)/sizeof(supersetv[0]); i < n; i++)
+    g_hash_table_add (superset_table, supersetv[i]);
+
+  for (i = 0, n = sizeof(subsetv)/sizeof(subsetv[0]); i < n; i++)
+    if (!g_hash_table_contains (superset_table, subsetv[i]))
+      goto fail;
+
+  ret = TRUE;
+out:
+  if (superset_table)
+    g_hash_table_destroy (superset_table);
+  g_strfreev (supersetv);
+  g_strfreev (subsetv);
+  return ret;
+fail:
+  ret = FALSE;
+  goto out;
+}
+
 gboolean
 stp_on_gst_bus_message (GstBus       *bus,
                         GstMessage   *msg,
diff --git a/src/lib.h b/src/lib.h
index f97b0de..6c0f771 100644
--- a/src/lib.h
+++ b/src/lib.h
@@ -104,6 +104,8 @@ guint stp_get_stream_type_from_string (const char *type);
 
 gboolean stp_validate_token_server (GInetAddressMask  *mask,
                                     SoupClientContext *client);
+gboolean stp_clients_is_subset (char *superset,
+                                char *subset);
 
 void stp_server_ctx_cleanup (STPServerCtx *ctx);
 void stp_client_ctx_cleanup (STPClientCtx *ctx);
diff --git a/src/main.c b/src/main.c
index 8d13d7c..e88ccae 100644
--- a/src/main.c
+++ b/src/main.c
@@ -123,12 +123,18 @@ stp_validate_fetch_token_from_query (GHashTable  *tokens,
 
   /* Only needed for RTP streaming */
   udp_clients = g_hash_table_lookup (query, "udp-clients");
-  if (!udp_clients) {
+  token->udp_clients = g_strdup (udp_clients);
+
+  if (!token->udp_clients) {
     *http_status_code = SOUP_STATUS_BAD_REQUEST;
     goto err;
   }
 
-  token->udp_clients = g_strdup (udp_clients);
+  if (!stp_clients_is_subset (perms_token->udp_clients,
+                              token->udp_clients)) {
+    *http_status_code = SOUP_STATUS_FORBIDDEN;
+    goto err;
+  }
 
 out:
   g_hash_table_destroy (query);
-- 
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