diff --git a/cpp/ql/test/library-tests/dataflow/security-taint/tainted.expected b/cpp/ql/test/library-tests/dataflow/security-taint/tainted.expected
new file mode 100644
index 00000000000..7359b068d8e
--- /dev/null
+++ b/cpp/ql/test/library-tests/dataflow/security-taint/tainted.expected
@@ -0,0 +1,54 @@
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:8:24:8:25 | s1 |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:23:14:23:19 | envStr |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:23:23:23:28 | call to getenv |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:23:23:23:40 | (const char *)... |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:25:6:25:29 | ! ... |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:25:7:25:12 | call to strcmp |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:25:7:25:29 | (bool)... |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:25:14:25:19 | envStr |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:29:6:29:28 | ! ... |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:29:7:29:12 | call to strcmp |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:29:7:29:28 | (bool)... |  |
+| test.cpp:23:23:23:28 | call to getenv | test.cpp:29:14:29:19 | envStr |  |
+| test.cpp:38:23:38:28 | call to getenv | test.cpp:8:24:8:25 | s1 |  |
+| test.cpp:38:23:38:28 | call to getenv | test.cpp:38:14:38:19 | envStr |  |
+| test.cpp:38:23:38:28 | call to getenv | test.cpp:38:23:38:28 | call to getenv |  |
+| test.cpp:38:23:38:28 | call to getenv | test.cpp:38:23:38:40 | (const char *)... |  |
+| test.cpp:38:23:38:28 | call to getenv | test.cpp:40:14:40:19 | envStr |  |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:8:24:8:25 | s1 | envStrGlobal |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:45:13:45:24 | envStrGlobal |  |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:45:13:45:24 | envStrGlobal | envStrGlobal |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:49:14:49:19 | envStr |  |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:49:23:49:28 | call to getenv |  |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:49:23:49:40 | (const char *)... |  |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:50:15:50:24 | envStr_ptr |  |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:50:15:50:24 | envStr_ptr | envStrGlobal |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:50:28:50:40 | & ... | envStrGlobal |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:50:29:50:40 | envStrGlobal | envStrGlobal |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:52:2:52:12 | * ... |  |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:52:3:52:12 | envStr_ptr |  |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:52:16:52:21 | envStr |  |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:54:6:54:35 | ! ... | envStrGlobal |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:54:7:54:12 | call to strcmp | envStrGlobal |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:54:7:54:35 | (bool)... | envStrGlobal |
+| test.cpp:49:23:49:28 | call to getenv | test.cpp:54:14:54:25 | envStrGlobal | envStrGlobal |
+| test.cpp:60:29:60:34 | call to getenv | test.cpp:10:27:10:27 | s |  |
+| test.cpp:60:29:60:34 | call to getenv | test.cpp:60:18:60:25 | userName |  |
+| test.cpp:60:29:60:34 | call to getenv | test.cpp:60:29:60:34 | call to getenv |  |
+| test.cpp:60:29:60:34 | call to getenv | test.cpp:60:29:60:47 | (const char *)... |  |
+| test.cpp:60:29:60:34 | call to getenv | test.cpp:64:25:64:32 | userName |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:11:20:11:21 | s1 |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:11:36:11:37 | s2 |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:67:7:67:13 | copying |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:68:17:68:24 | userName |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:68:28:68:33 | call to getenv |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:68:28:68:46 | (const char *)... |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:69:10:69:13 | copy |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:70:5:70:10 | call to strcpy |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:70:12:70:15 | copy |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:70:18:70:25 | userName |  |
+| test.cpp:68:28:68:33 | call to getenv | test.cpp:71:12:71:15 | copy |  |
+| test.cpp:75:20:75:25 | call to getenv | test.cpp:15:22:15:25 | nptr |  |
+| test.cpp:75:20:75:25 | call to getenv | test.cpp:75:15:75:18 | call to atoi |  |
+| test.cpp:75:20:75:25 | call to getenv | test.cpp:75:20:75:25 | call to getenv |  |
+| test.cpp:75:20:75:25 | call to getenv | test.cpp:75:20:75:45 | (const char *)... |  |
diff --git a/cpp/ql/test/library-tests/dataflow/security-taint/tainted.ql b/cpp/ql/test/library-tests/dataflow/security-taint/tainted.ql
new file mode 100644
index 00000000000..64a724c4cab
--- /dev/null
+++ b/cpp/ql/test/library-tests/dataflow/security-taint/tainted.ql
@@ -0,0 +1,7 @@
+import semmle.code.cpp.security.TaintTracking
+
+from Expr source, Element tainted, string globalVar
+where
+  taintedIncludingGlobalVars(source, tainted, globalVar) and
+  not tainted.getLocation().getFile().getExtension() = "h"
+select source, tainted, globalVar
diff --git a/cpp/ql/test/library-tests/dataflow/security-taint/test.cpp b/cpp/ql/test/library-tests/dataflow/security-taint/test.cpp
new file mode 100644
index 00000000000..5eb7ee79b46
--- /dev/null
+++ b/cpp/ql/test/library-tests/dataflow/security-taint/test.cpp
@@ -0,0 +1,78 @@
+// Test for the general-purpose taint-tracking
+// mechanism that is used by several of the security queries.
+
+///// Library functions //////
+
+typedef unsigned long size_t;
+
+int strcmp(const char *s1, const char *s2);
+char *getenv(const char *name);
+size_t strlen(const char *s);
+char *strcpy(char *s1, const char *s2);
+
+void *malloc(size_t size);
+
+int atoi(const char *nptr);
+
+//// Test code /////
+
+bool isAdmin = false;
+
+void test1()
+{
+	const char *envStr = getenv("USERINFO");
+
+	if (!strcmp(envStr, "admin")) {
+		isAdmin = true;
+	}
+
+	if (!strcmp(envStr, "none")) {
+		isAdmin = false;
+	}
+}
+
+extern const char *specialUser;
+
+void test2()
+{
+	const char *envStr = getenv("USERINFO");
+
+	if (!strcmp(envStr, specialUser)) {
+		isAdmin = true;
+	}
+}
+
+const char *envStrGlobal;
+
+void test3()
+{
+	const char *envStr = getenv("USERINFO");
+	const char **envStr_ptr = &envStrGlobal;
+
+	*envStr_ptr = envStr;
+
+	if (!strcmp(envStrGlobal, "admin")) {
+		isAdmin = true;
+	}
+}
+
+void bugWithBinop() {
+     const char *userName = getenv("USER_NAME");
+
+     // The following is tainted, but should not cause
+     // the whole program to be considered tainted.
+     int bytes = strlen(userName) + 1;
+}
+
+char* copying() {
+    const char *userName = getenv("USER_NAME");
+    char copy[1024];
+    strcpy(copy, userName);
+    return copy; // copy should be tainted
+}
+
+void guard() {
+    int len = atoi(getenv("FOOBAZ_BRANCHING"));
+    if (len > 1000) return;
+    char **node = (char **) malloc(len * sizeof(char *));
+}