[clang][analyzer] Move PutenvStackArrayChecker out of alpha package

[balazske]

Checker alpha.security.PutenvStackArray is moved to security.PutenvStackArray.

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-static-analyzer-1

Author: Balázs Kéri (balazske)

Changes

Checker alpha.security.PutenvStackArray is moved to security.PutenvStackArray.

---

Full diff: https://github.com/llvm/llvm-project/pull/93980.diff

3 Files Affected:

• (modified) clang/docs/analyzer/checkers.rst (+35-35)
• (modified) clang/include/clang/StaticAnalyzer/Checkers/Checkers.td (+5-5)
• (modified) clang/test/Analysis/putenv-stack-array.c (+1-1)

diff --git a/clang/docs/analyzer/checkers.rst b/clang/docs/analyzer/checkers.rst
index 3a31708a1e9de..ac13f731e508e 100644
--- a/clang/docs/analyzer/checkers.rst
+++ b/clang/docs/analyzer/checkers.rst
@@ -1179,6 +1179,41 @@ security.insecureAPI.DeprecatedOrUnsafeBufferHandling (C)
    strncpy(buf, "a", 1); // warn
  }
 
+.. _security-putenv-stack-array:
+
+security.PutenvStackArray (C)
+"""""""""""""""""""""""""""""
+Finds calls to the ``putenv`` function which pass a pointer to a stack-allocated
+(automatic) array as the argument. Function ``putenv`` does not copy the passed
+string, only a pointer to the data is stored and this data can be read even by
+other threads. Content of a stack-allocated array is likely to be overwritten
+after returning from the parent function.
+
+The problem can be solved by using a static array variable or dynamically
+allocated memory. Even better is to avoid using ``putenv`` (it has other
+problems related to memory leaks) and use ``setenv`` instead.
+
+The check corresponds to CERT rule
+`POS34-C. Do not call putenv() with a pointer to an automatic variable as the argument
+<https://wiki.sei.cmu.edu/confluence/display/c/POS34-C.+Do+not+call+putenv%28%29+with+a+pointer+to+an+automatic+variable+as+the+argument>`_.
+
+.. code-block:: c
+
+  int f() {
+    char env[] = "NAME=value";
+    return putenv(env); // putenv function should not be called with stack-allocated string
+  }
+
+There is one case where the checker can report a false positive. This is when
+the stack-allocated array is used at `putenv` in a function or code branch that
+does not return (calls `fork` or `exec` like function).
+
+Another special case is if the `putenv` is called from function `main`. Here
+the stack is deallocated at the end of the program and it should be no problem
+to use the stack-allocated string (a multi-threaded program may require more
+attention). The checker does not warn for cases when stack space of `main` is
+used at the `putenv` call.
+
 security.SetgidSetuidOrder (C)
 """"""""""""""""""""""""""""""
 When dropping user-level and group-level privileges in a program by using
@@ -2833,41 +2868,6 @@ Warn on mmap() calls that are both writable and executable.
    //       code
  }
 
-.. _alpha-security-putenv-stack-array:
-
-alpha.security.PutenvStackArray (C)
-"""""""""""""""""""""""""""""""""""
-Finds calls to the ``putenv`` function which pass a pointer to a stack-allocated
-(automatic) array as the argument. Function ``putenv`` does not copy the passed
-string, only a pointer to the data is stored and this data can be read even by
-other threads. Content of a stack-allocated array is likely to be overwritten
-after returning from the parent function.
-
-The problem can be solved by using a static array variable or dynamically
-allocated memory. Even better is to avoid using ``putenv`` (it has other
-problems related to memory leaks) and use ``setenv`` instead.
-
-The check corresponds to CERT rule
-`POS34-C. Do not call putenv() with a pointer to an automatic variable as the argument
-<https://wiki.sei.cmu.edu/confluence/display/c/POS34-C.+Do+not+call+putenv%28%29+with+a+pointer+to+an+automatic+variable+as+the+argument>`_.
-
-.. code-block:: c
-
-  int f() {
-    char env[] = "NAME=value";
-    return putenv(env); // putenv function should not be called with stack-allocated string
-  }
-
-There is one case where the checker can report a false positive. This is when
-the stack-allocated array is used at `putenv` in a function or code branch that
-does not return (calls `fork` or `exec` like function).
-
-Another special case is if the `putenv` is called from function `main`. Here
-the stack is deallocated at the end of the program and it should be no problem
-to use the stack-allocated string (a multi-threaded program may require more
-attention). The checker does not warn for cases when stack space of `main` is
-used at the `putenv` call.
-
 .. _alpha-security-ReturnPtrRange:
 
 alpha.security.ReturnPtrRange (C)
diff --git a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
index 40f443047bd4b..9ab8e42f7cdcd 100644
--- a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
+++ b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
@@ -1011,6 +1011,11 @@ def FloatLoopCounter : Checker<"FloatLoopCounter">,
   Dependencies<[SecuritySyntaxChecker]>,
   Documentation<HasDocumentation>;
 
+def PutenvStackArray : Checker<"PutenvStackArray">,
+  HelpText<"Finds calls to the function 'putenv' which pass a pointer to "
+           "an automatic (stack-allocated) array as the argument.">,
+  Documentation<HasDocumentation>;
+
 def SetgidSetuidOrderChecker : Checker<"SetgidSetuidOrder">,
   HelpText<"Warn on possible reversed order of 'setgid(getgid()))' and "
            "'setuid(getuid())' (CERT: POS36-C)">,
@@ -1065,11 +1070,6 @@ def MmapWriteExecChecker : Checker<"MmapWriteExec">,
   ]>,
   Documentation<HasDocumentation>;
 
-def PutenvStackArray : Checker<"PutenvStackArray">,
-  HelpText<"Finds calls to the function 'putenv' which pass a pointer to "
-           "an automatic (stack-allocated) array as the argument.">,
-  Documentation<HasDocumentation>;
-
 def ReturnPointerRangeChecker : Checker<"ReturnPtrRange">,
   HelpText<"Check for an out-of-bound pointer being returned to callers">,
   Documentation<HasDocumentation>;
diff --git a/clang/test/Analysis/putenv-stack-array.c b/clang/test/Analysis/putenv-stack-array.c
index f28aed73031d3..2099ef4160f85 100644
--- a/clang/test/Analysis/putenv-stack-array.c
+++ b/clang/test/Analysis/putenv-stack-array.c
@@ -1,5 +1,5 @@
 // RUN: %clang_analyze_cc1 \
-// RUN:  -analyzer-checker=alpha.security.PutenvStackArray \
+// RUN:  -analyzer-checker=security.PutenvStackArray \
 // RUN:  -verify %s
 
 #include "Inputs/system-header-simulator.h"

[balazske]

I found this one report that is a false positive. This looks not easy to fix and it is the case that is described in the documentation.

[steakhal]

I have only a handful of remarks. LGTM otherwise.