C++: Add a test case.

Author: geoffw0

cpp/ql/test/query-tests/Security/CWE/CWE-311/semmle/tests/CleartextTransmission.expected

@@ -84,6 +84,7 @@ edges
 | test3.cpp:350:9:350:16 | password | test3.cpp:352:16:352:23 | password |
 | test3.cpp:350:9:350:16 | password | test3.cpp:353:4:353:18 | call to decrypt_inplace |
 | test3.cpp:350:9:350:16 | password | test3.cpp:353:20:353:27 | password |
+| test3.cpp:366:8:366:15 | password | test3.cpp:368:15:368:22 | password |
 | test.cpp:41:23:41:43 | cleartext password! | test.cpp:48:21:48:27 | call to encrypt |
 | test.cpp:41:23:41:43 | cleartext password! | test.cpp:48:29:48:39 | thePassword |
 | test.cpp:66:23:66:43 | cleartext password! | test.cpp:76:21:76:27 | call to encrypt |
@@ -195,6 +196,8 @@ nodes
 | test3.cpp:352:16:352:23 | password | semmle.label | password |
 | test3.cpp:353:4:353:18 | call to decrypt_inplace | semmle.label | call to decrypt_inplace |
 | test3.cpp:353:20:353:27 | password | semmle.label | password |
+| test3.cpp:366:8:366:15 | password | semmle.label | password |
+| test3.cpp:368:15:368:22 | password | semmle.label | password |
 | test.cpp:41:23:41:43 | cleartext password! | semmle.label | cleartext password! |
 | test.cpp:48:21:48:27 | call to encrypt | semmle.label | call to encrypt |
 | test.cpp:48:29:48:39 | thePassword | semmle.label | thePassword |
@@ -226,3 +229,4 @@ subpaths
 | test3.cpp:295:2:295:5 | call to send | test3.cpp:308:58:308:66 | password2 | test3.cpp:295:14:295:17 | data | This operation transmits 'data', which may contain unencrypted sensitive data from $@ | test3.cpp:308:58:308:66 | password2 | password2 |
 | test3.cpp:300:2:300:5 | call to send | test3.cpp:308:58:308:66 | password2 | test3.cpp:300:14:300:17 | data | This operation transmits 'data', which may contain unencrypted sensitive data from $@ | test3.cpp:308:58:308:66 | password2 | password2 |
 | test3.cpp:341:4:341:7 | call to recv | test3.cpp:339:9:339:16 | password | test3.cpp:341:16:341:23 | password | This operation receives into 'password', which may put unencrypted sensitive data into $@ | test3.cpp:339:9:339:16 | password | password |
+| test3.cpp:368:3:368:6 | call to recv | test3.cpp:366:8:366:15 | password | test3.cpp:368:15:368:22 | password | This operation receives into 'password', which may put unencrypted sensitive data into $@ | test3.cpp:366:8:366:15 | password | password |

cpp/ql/test/query-tests/Security/CWE/CWE-311/semmle/tests/test3.cpp

@@ -356,3 +356,21 @@ void test_loops()
 		}
 	}
 }
+
+void DoDisguisedOperation(char *buffer, size_t size);
+void SecureZeroBuffer(char *buffer, size_t size);
+
+void test_securezero()
+{
+	{
+		char password[256];
+
+		recv(val(), password, 256, val()); // GOOD: password is (probably) encrypted [FALSE POSITIVE]
+
+		DoDisguisedOperation(password, 256); // decryption (disguised)
+
+		// ...
+
+		SecureZeroBuffer(password, 256); // evidence we may have been doing decryption
+	}
+}