From c4a34b71d4f51f071f7a722059e36388b41d30e4 Mon Sep 17 00:00:00 2001
From: Evgeny Vereshchagin <[email protected]>
Date: Mon, 11 Mar 2019 21:05:13 +0100
Subject: [PATCH] lgtm: replace the query used for looking for fgets with a
 more general query

to make it easier to comlain about `strtok` :-)

Inspired by https://github.com/systemd/systemd/pull/11963, which, in turn,
was prompted by https://github.com/systemd/systemd/pull/11555.

(cherry picked from commit 7ba5ded9dbd7737bc368521f5ea7c90e5b06ab3e)

Related: #2017033
---
 .../PotentiallyDangerousFunction.ql           | 30 +++++++++++++++++++
 .lgtm/cpp-queries/fgets.ql                    | 21 -------------
 2 files changed, 30 insertions(+), 21 deletions(-)
 create mode 100644 .lgtm/cpp-queries/PotentiallyDangerousFunction.ql
 delete mode 100644 .lgtm/cpp-queries/fgets.ql

diff --git a/.lgtm/cpp-queries/PotentiallyDangerousFunction.ql b/.lgtm/cpp-queries/PotentiallyDangerousFunction.ql
new file mode 100644
index 0000000000..ba80f4ad8c
--- /dev/null
+++ b/.lgtm/cpp-queries/PotentiallyDangerousFunction.ql
@@ -0,0 +1,30 @@
+/**
+ * @name Use of potentially dangerous function
+ * @description Certain standard library functions are dangerous to call.
+ * @kind problem
+ * @problem.severity error
+ * @precision high
+ * @id cpp/potentially-dangerous-function
+ * @tags reliability
+ *       security
+ *
+ * Borrowed from
+ * https://github.com/Semmle/ql/blob/master/cpp/ql/src/Security/CWE/CWE-676/PotentiallyDangerousFunction.ql
+ */
+import cpp
+
+predicate potentiallyDangerousFunction(Function f, string message) {
+  (
+    f.getQualifiedName() = "fgets" and
+    message = "Call to fgets is potentially dangerous. Use read_line() instead."
+  ) or (
+    f.getQualifiedName() = "strtok" and
+    message = "Call to strtok is potentially dangerous. Use extract_first_word() instead."
+  )
+}
+
+from FunctionCall call, Function target, string message
+where
+  call.getTarget() = target and
+  potentiallyDangerousFunction(target, message)
+select call, message
diff --git a/.lgtm/cpp-queries/fgets.ql b/.lgtm/cpp-queries/fgets.ql
deleted file mode 100644
index a4181e4f3d..0000000000
--- a/.lgtm/cpp-queries/fgets.ql
+++ /dev/null
@@ -1,21 +0,0 @@
-/**
- * @name Use of fgets()
- * @description fgets() is dangerous to call. Use read_line() instead.
- * @kind problem
- * @problem.severity error
- * @precision high
- * @id cpp/fgets
- * @tags reliability
- *       security
- */
-import cpp
-
-predicate dangerousFunction(Function function) {
-  exists (string name | name = function.getQualifiedName() |
-    name = "fgets")
-}
-
-from FunctionCall call, Function target
-where call.getTarget() = target
-  and dangerousFunction(target)
-select call, target.getQualifiedName() + " is potentially dangerous"