[analyzer] Delete alpha.security.MallocOverflow

clang/docs/ReleaseNotes.rst

@@ -347,6 +347,11 @@ Improvements
 Moved checkers
 ^^^^^^^^^^^^^^
 
+- The checker ``alpha.security.MallocOverflow`` was deleted because it was
+  badly implemented and its agressive logic produced too many false positives.
+  To detect too large arguments passed to malloc, consider using the checker
+  ``alpha.taint.TaintedAlloc``.
+
 .. _release-notes-sanitizers:
 
 Sanitizers

clang/docs/analyzer/checkers.rst

@@ -2951,49 +2951,6 @@ Warn about buffer overflows (newer checker).
    char c = s[x]; // warn: index is tainted
  }
 
-.. _alpha-security-MallocOverflow:
-
-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.
-
-.. code-block:: c
-
- void test(int n) {
-   void *p = malloc(n * sizeof(int)); // warn
- }
-
- void test2(int n) {
-   if (n > 100) // gives an upper-bound
-     return;
-   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.
-
- - 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)

clang/include/clang/StaticAnalyzer/Checkers/Checkers.td

@@ -1039,10 +1039,6 @@ def ArrayBoundCheckerV2 : Checker<"ArrayBoundV2">,
   HelpText<"Warn about buffer overflows (newer checker)">,
   Documentation<HasDocumentation>;
 
-def MallocOverflowSecurityChecker : Checker<"MallocOverflow">,
-  HelpText<"Check for overflows in the arguments to malloc()">,
-  Documentation<HasDocumentation>;
-
 def MmapWriteExecChecker : Checker<"MmapWriteExec">,
   HelpText<"Warn on mmap() calls that are both writable and executable">,
   Documentation<HasDocumentation>;

clang/lib/StaticAnalyzer/Checkers/CMakeLists.txt

@@ -63,7 +63,6 @@ add_clang_library(clangStaticAnalyzerCheckers
   MacOSKeychainAPIChecker.cpp
   MacOSXAPIChecker.cpp
   MallocChecker.cpp
-  MallocOverflowSecurityChecker.cpp
   MallocSizeofChecker.cpp
   MismatchedIteratorChecker.cpp
   MmapWriteExecChecker.cpp