devtools: Add security-check.py

Perform the following ELF security checks:

- PIE: Check for position independent executable (PIE), allowing for address space randomization
- NX: Check that no sections are writable and executable (including the stack)
- RELRO: Check for read-only relocations, binding at startup
- Canary: Check for use of stack canary

Also add a check to symbol-check.py that checks that only the subset of
allowed libraries is imported (to avoid incompatibilities).

contrib/devtools/test-security-check.py

@@ -0,0 +1,60 @@
+#!/usr/bin/python2
+'''
+Test script for security-check.py
+'''
+from __future__ import division,print_function
+import subprocess
+import sys
+import unittest
+
+def write_testcode(filename):
+    with open(filename, 'w') as f:
+        f.write('''
+    #include <stdio.h>
+    int main()
+    {
+        printf("the quick brown fox jumps over the lazy god\\n");
+        return 0;
+    }
+    ''')
+
+def call_security_check(cc, source, executable, options):
+    subprocess.check_call([cc,source,'-o',executable] + options)
+    p = subprocess.Popen(['./security-check.py',executable], stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
+    (stdout, stderr) = p.communicate()
+    return (p.returncode, stdout.rstrip())
+
+class TestSecurityChecks(unittest.TestCase):
+    def test_ELF(self):
+        source = 'test1.c'
+        executable = 'test1'
+        cc = 'gcc'
+        write_testcode(source)
+
+        self.assertEqual(call_security_check(cc, source, executable, ['-Wl,-zexecstack','-fno-stack-protector','-Wl,-znorelro']), 
+                (1, executable+': failed PIE NX RELRO Canary'))
+        self.assertEqual(call_security_check(cc, source, executable, ['-Wl,-znoexecstack','-fno-stack-protector','-Wl,-znorelro']), 
+                (1, executable+': failed PIE RELRO Canary'))
+        self.assertEqual(call_security_check(cc, source, executable, ['-Wl,-znoexecstack','-fstack-protector-all','-Wl,-znorelro']), 
+                (1, executable+': failed PIE RELRO'))
+        self.assertEqual(call_security_check(cc, source, executable, ['-Wl,-znoexecstack','-fstack-protector-all','-Wl,-znorelro','-pie','-fPIE']), 
+                (1, executable+': failed RELRO'))
+        self.assertEqual(call_security_check(cc, source, executable, ['-Wl,-znoexecstack','-fstack-protector-all','-Wl,-zrelro','-Wl,-z,now','-pie','-fPIE']), 
+                (0, ''))
+
+    def test_PE(self):
+        source = 'test1.c'
+        executable = 'test1.exe'
+        cc = 'i686-w64-mingw32-gcc'
+        write_testcode(source)
+
+        self.assertEqual(call_security_check(cc, source, executable, []), 
+                (1, executable+': failed PIE NX'))
+        self.assertEqual(call_security_check(cc, source, executable, ['-Wl,--nxcompat']), 
+                (1, executable+': failed PIE'))
+        self.assertEqual(call_security_check(cc, source, executable, ['-Wl,--nxcompat','-Wl,--dynamicbase']), 
+                (0, ''))
+
+if __name__ == '__main__':
+    unittest.main()
+