alpha.security.MallocOverflow (C)
"""""""""""""""""""""""""""""""""
-Check for overflows in the arguments to ``malloc()``.
-It tries to catch ``malloc(n * c)`` patterns, where:
- - ``n``: a variable or member access of an object
- - ``c``: a constant foldable integral
-
-This checker was designed for code audits, so expect false-positive reports.
-One is supposed to silence this checker by ensuring proper bounds checking on
-the variable in question using e.g. an ``assert()`` or a branch.
+Check for overflows in the arguments to malloc().
.. code-block:: c
void *p = malloc(n * sizeof(int)); // no warning
}
- void test3(int n) {
- assert(n <= 100 && "Contract violated.");
- void *p = malloc(n * sizeof(int)); // no warning
- }
-
-Limitations:
- - The checker won't warn for variables involved in explicit casts,
- since that might limit the variable's domain.
- E.g.: ``(unsigned char)int x`` would limit the domain to ``[0,255]``.
- The checker will miss the true-positive cases when the explicit cast would
- not tighten the domain to prevent the overflow in the subsequent
- multiplication operation.
-
- - If the variable ``n`` participates in a comparison anywhere in the enclosing
- function's scope, even after the ``malloc()``, the report will be still
- suppressed.
-
- - It is an AST-based checker, thus it does not make use of the
- path-sensitive taint-analysis.
-
.. _alpha-security-MmapWriteExec:
alpha.security.MmapWriteExec (C)