Add a new check, cert-env33-c, that diagnoses uses of system(), popen(), and _popen() to execute a command processor. This check corresponds to the CERT secure coding rule: https://www.securecoding.cert.org/confluence/pages/viewpage.action?pageId=2130132

llvm-svn: 261530

1 files changed, 45 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/cert/CommandProcessorCheck.cpp b/clang-tools-extra/clang-tidy/cert/CommandProcessorCheck.cpp
new file mode 100644
index 00000000000..e2dbeca20c1
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/cert/CommandProcessorCheck.cpp
@@ -0,0 +1,45 @@
+//===--- Env33CCheck.cpp - clang-tidy--------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CommandProcessorCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace cert {
+
+void CommandProcessorCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      callExpr(
+          callee(functionDecl(anyOf(hasName("::system"), hasName("::popen"),
+                                    hasName("::_popen")))
+                     .bind("func")),
+          // Do not diagnose when the call expression passes a null pointer
+          // constant to system(); that only checks for the presence of a
+          // command processor, which is not a security risk by itself.
+          unless(callExpr(callee(functionDecl(hasName("::system"))),
+                          argumentCountIs(1),
+                          hasArgument(0, nullPointerConstant()))))
+          .bind("expr"),
+      this);
+}
+
+void CommandProcessorCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *Fn = Result.Nodes.getNodeAs<FunctionDecl>("func");
+  const auto *E = Result.Nodes.getNodeAs<CallExpr>("expr");
+
+  diag(E->getExprLoc(), "calling %0 uses a command processor") << Fn;
+}
+
+} // namespace cert
+} // namespace tidy
+} // namespace clang