rtsp-media: Don't crash on encrypted RTX SDP

In parse_keymgmt(), don't mutate the input string that's been passed
as const, especially since we might need the original value again if
the same key info applies to multiple streams (RTX, for example).

https://bugzilla.gnome.org/show_bug.cgi?id=754753

1 files changed, 19 insertions, 9 deletions

diff --git a/gst/rtsp-server/rtsp-media.c b/gst/rtsp-server/rtsp-media.c
index 2483504a4d..adccff920a 100644
--- a/gst/rtsp-server/rtsp-media.c
+++ b/gst/rtsp-server/rtsp-media.c
@@ -3356,7 +3356,6 @@ static gboolean
 parse_keymgmt (const gchar * keymgmt, GstCaps * caps)
 {
   gboolean res = FALSE;
-  gchar *p, *kmpid;
   gsize size;
   guchar *data;
   GstMIKEYMessage *msg;
@@ -3364,17 +3363,28 @@ parse_keymgmt (const gchar * keymgmt, GstCaps * caps)
   const gchar *srtp_cipher;
   const gchar *srtp_auth;
 
-  p = (gchar *) keymgmt;
+  {
+    gchar *orig_value;
+    gchar *p, *kmpid;
 
-  SKIP_SPACES (p);
-  if (*p == '\0')
-    return FALSE;
+    p = orig_value = g_strdup (keymgmt);
 
-  PARSE_STRING (p, " ", kmpid);
-  if (!g_str_equal (kmpid, "mikey"))
-    return FALSE;
+    SKIP_SPACES (p);
+    if (*p == '\0') {
+      g_free (orig_value);
+      return FALSE;
+    }
+
+    PARSE_STRING (p, " ", kmpid);
+    if (kmpid == NULL || !g_str_equal (kmpid, "mikey")) {
+      g_free (orig_value);
+      return FALSE;
+    }
+    data = g_base64_decode (p, &size);
+
+    g_free (orig_value);        /* Don't need this any more */
+  }
 
-  data = g_base64_decode (p, &size);
   if (data == NULL)
     return FALSE;