Merge pull request #4898 from JLLeitschuh/feat/JLL/system_get_property

Add MethodAccessSystemGetProperty predicate

java/ql/src/semmle/code/java/JDK.qll

@@ -211,6 +211,21 @@ class MethodSystemGetProperty extends Method {
   }
 }
 
+/**
+ * An access to a method named `getProperty` on class `java.lang.System`.
+ */
+class MethodAccessSystemGetProperty extends MethodAccess {
+  MethodAccessSystemGetProperty() { getMethod() instanceof MethodSystemGetProperty }
+
+  /**
+   * Holds if this call has a compile-time constant first argument with the value `propertyName`.
+   * For example: `System.getProperty("user.dir")`.
+   */
+  predicate hasCompileTimeConstantGetPropertyName(string propertyName) {
+    this.getArgument(0).(CompileTimeConstantExpr).getStringValue() = propertyName
+  }
+}
+
 /**
  * Any method named `exit` on class `java.lang.Runtime` or `java.lang.System`.
  */

java/ql/test/library-tests/JDK/PrintAst.expected

@@ -60,3 +60,38 @@ jdk/A.java:
 #   28|             0: [ArrayTypeAccess] ...[]
 #   28|               0: [TypeAccess] String
 #   28|       5: [BlockStmt] stmt
+jdk/SystemGetPropertyCall.java:
+#    0| [CompilationUnit] SystemGetPropertyCall
+#    3|   1: [Class] SystemGetPropertyCall
+#    4|     3: [FieldDeclaration] String USER_DIR_PROPERTY, ...;
+#    4|       -1: [TypeAccess] String
+#    4|       0: [StringLiteral] "user.dir"
+#    6|     4: [Method] a
+#    6|       3: [TypeAccess] void
+#    6|       5: [BlockStmt] stmt
+#    7|         0: [ExprStmt] stmt
+#    7|           0: [MethodAccess] getProperty(...)
+#    7|             -1: [TypeAccess] System
+#    7|             0: [StringLiteral] "user.dir"
+#   10|     5: [Method] b
+#   10|       3: [TypeAccess] void
+#   10|       5: [BlockStmt] stmt
+#   11|         0: [ExprStmt] stmt
+#   11|           0: [MethodAccess] getProperty(...)
+#   11|             -1: [TypeAccess] System
+#   11|             0: [StringLiteral] "user.dir"
+#   11|             1: [StringLiteral] "HOME"
+#   14|     6: [Method] c
+#   14|       3: [TypeAccess] void
+#   14|       5: [BlockStmt] stmt
+#   15|         0: [ExprStmt] stmt
+#   15|           0: [MethodAccess] getProperty(...)
+#   15|             -1: [TypeAccess] System
+#   15|             0: [VarAccess] USER_DIR_PROPERTY
+#   18|     7: [Method] d
+#   18|       3: [TypeAccess] void
+#   18|       5: [BlockStmt] stmt
+#   19|         0: [ExprStmt] stmt
+#   19|           0: [MethodAccess] getProperty(...)
+#   19|             -1: [TypeAccess] System
+#   19|             0: [StringLiteral] "random.property"

java/ql/test/library-tests/JDK/SystemGetPropertyCall.expected

@@ -0,0 +1,3 @@
+| jdk/SystemGetPropertyCall.java:7:9:7:38 | getProperty(...) |
+| jdk/SystemGetPropertyCall.java:11:9:11:46 | getProperty(...) |
+| jdk/SystemGetPropertyCall.java:15:9:15:45 | getProperty(...) |

java/ql/test/library-tests/JDK/SystemGetPropertyCall.ql

@@ -0,0 +1,5 @@
+import java
+
+from MethodAccessSystemGetProperty ma
+where ma.hasCompileTimeConstantGetPropertyName("user.dir")
+select ma

java/ql/test/library-tests/JDK/jdk/SystemGetPropertyCall.java

@@ -0,0 +1,21 @@
+package jdk;
+
+public class SystemGetPropertyCall {
+    private static final String USER_DIR_PROPERTY = "user.dir";
+
+    void a() {
+        System.getProperty("user.dir");
+    }
+
+    void b() {
+        System.getProperty("user.dir", "HOME");
+    }
+
+    void c() {
+        System.getProperty(USER_DIR_PROPERTY);
+    }
+
+    void d() {
+        System.getProperty("random.property");
+    }
+}