GPL License added

exam1/execve-stack.nasm

@@ -1,3 +1,16 @@
+;    This program is free software: you can redistribute it and/or modify
+;    it under the terms of the GNU General Public License as published by
+;    the Free Software Foundation, either version 3 of the License, or
+;    (at your option) any later version.
+
+;    This program is distributed in the hope that it will be useful,
+;    but WITHOUT ANY WARRANTY; without even the implied warranty of
+;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;    GNU General Public License for more details.
+
+;    You should have received a copy of the GNU General Public License
+;    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 ; Filename: execve-stack.nasm
 ; Author: Andrey Arapov <andrey.arapov@gmail.com>
 ; 2013 March

exam1/shell_bind_tcp.nasm

@@ -1,3 +1,16 @@
+;    This program is free software: you can redistribute it and/or modify
+;    it under the terms of the GNU General Public License as published by
+;    the Free Software Foundation, either version 3 of the License, or
+;    (at your option) any later version.
+
+;    This program is distributed in the hope that it will be useful,
+;    but WITHOUT ANY WARRANTY; without even the implied warranty of
+;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;    GNU General Public License for more details.
+
+;    You should have received a copy of the GNU General Public License
+;    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 ; Filename: shell_bind_tcp.nasm
 ; Author: Andrey Arapov <andrey.arapov@gmail.com>
 ; 2013 March

exam1/shell_bind_tcp_smaller.nasm

@@ -1,3 +1,16 @@
+;    This program is free software: you can redistribute it and/or modify
+;    it under the terms of the GNU General Public License as published by
+;    the Free Software Foundation, either version 3 of the License, or
+;    (at your option) any later version.
+
+;    This program is distributed in the hope that it will be useful,
+;    but WITHOUT ANY WARRANTY; without even the implied warranty of
+;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;    GNU General Public License for more details.
+
+;    You should have received a copy of the GNU General Public License
+;    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 ; Filename: shell_bind_tcp_smaller.nasm
 ; Author: Andrey Arapov <andrey.arapov@gmail.com>
 ; 2013 March