[gtk-vnc] src: fix mem leaks in SASL, rich cursor and xcursor code

[Daniel P. Berrange <dberrange src gnome org>]

commit 603b5cf4dbe13947df44b2c65ade8130e85edf94
Author: Daniel P. Berrangé <dan berrange com>
Date:   Tue Mar 23 10:54:26 2021 +0000

    src: fix mem leaks in SASL, rich cursor and xcursor code
    
    Signed-off-by: Daniel P. Berrangé <berrange redhat com>

 src/vncconnection.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)
---
diff --git a/src/vncconnection.c b/src/vncconnection.c
index 2426afd..2d79a92 100644
--- a/src/vncconnection.c
+++ b/src/vncconnection.c
@@ -3060,8 +3060,12 @@ static void vnc_connection_rich_cursor(VncConnection *conn, guint16 x, guint16 y
 
         vnc_connection_read(conn, image, imagelen);
         vnc_connection_read(conn, mask, masklen);
-        if (vnc_connection_has_error(conn))
+        if (vnc_connection_has_error(conn)) {
+            g_free(image);
+            g_free(mask);
+            g_free(pixbuf);
             return;
+        }
 
         vnc_connection_rich_cursor_blt(conn, pixbuf, image, mask,
                                        width * (priv->fmt.bits_per_pixel/8),
@@ -3120,8 +3124,13 @@ static void vnc_connection_xcursor(VncConnection *conn, guint16 x, guint16 y, gu
 
         vnc_connection_read(conn, data, rowlen*height);
         vnc_connection_read(conn, mask, rowlen*height);
-        if (vnc_connection_has_error(conn))
+        if (vnc_connection_has_error(conn)) {
+            g_free(data);
+            g_free(mask);
+            g_free(pixbuf);
             return;
+        }
+
         datap = data;
         maskp = mask;
         pixp = (guint32*)pixbuf;
@@ -4377,7 +4386,7 @@ static gboolean vnc_connection_perform_auth_sasl(VncConnection *conn)
     };
     sasl_interact_t *interact = NULL;
     guint32 mechlistlen;
-    char *mechlist;
+    char *mechlist = NULL;
     const char *mechname;
     gboolean ret;
     GSocketAddress *addr;
@@ -4491,11 +4500,8 @@ static gboolean vnc_connection_perform_auth_sasl(VncConnection *conn)
     mechlist = g_malloc(mechlistlen+1);
     vnc_connection_read(conn, mechlist, mechlistlen);
     mechlist[mechlistlen] = '\0';
-    if (vnc_connection_has_error(conn)) {
-        g_free(mechlist);
-        mechlist = NULL;
+    if (vnc_connection_has_error(conn))
         goto error;
-    }
 
  restart:
     /* Start the auth negotiation on the client end first */
@@ -4510,8 +4516,6 @@ static gboolean vnc_connection_perform_auth_sasl(VncConnection *conn)
         vnc_connection_set_error(conn,
                                  "Failed to start SASL negotiation: %d (%s)",
                                  err, sasl_errdetail(saslconn));
-        g_free(mechlist);
-        mechlist = NULL;
         goto error;
     }
 
@@ -4701,12 +4705,14 @@ static gboolean vnc_connection_perform_auth_sasl(VncConnection *conn)
      * is defined to be sent unencrypted, and setting saslconn turns
      * on the SSF layer encryption processing */
     priv->saslconn = saslconn;
+    g_free(mechlist);
     return ret;
 
  error:
     if (saslconn)
         sasl_dispose(&saslconn);
     vnc_connection_auth_failure(conn, "Unknown authentication failure");
+    g_free(mechlist);
     return FALSE;
 }
 #endif /* HAVE_SASL */