From 7bfa6856113854ecf579f2e2ff191df74a2a02dd Mon Sep 17 00:00:00 2001 From: Aaron Ballman Date: Wed, 2 Nov 2016 14:16:36 +0000 Subject: [PATCH] Add a new clang-tidy check for cert-msc50-cpp (and cert-msc30-c) that corresponds to the CERT C++ secure coding rule: https://www.securecoding.cert.org/confluence/display/cplusplus/MSC50-CPP.+Do+not+use+std%3A%3Arand%28%29+for+generating+pseudorandom+numbers Patch by Benedek Kiss llvm-svn: 285809 --- .../clang-tidy/cert/CERTTidyModule.cpp | 7 ++++ .../clang-tidy/cert/CMakeLists.txt | 1 + .../cert/LimitedRandomnessCheck.cpp | 40 +++++++++++++++++++ .../clang-tidy/cert/LimitedRandomnessCheck.h | 38 ++++++++++++++++++ .../docs/clang-tidy/checks/cert-msc30-c.rst | 7 ++++ .../docs/clang-tidy/checks/cert-msc50-cpp.rst | 6 +++ .../docs/clang-tidy/checks/list.rst | 2 + .../test/clang-tidy/cert-limited-randomness.c | 13 ++++++ .../clang-tidy/cert-limited-randomness.cpp | 28 +++++++++++++ 9 files changed, 142 insertions(+) create mode 100644 clang-tools-extra/clang-tidy/cert/LimitedRandomnessCheck.cpp create mode 100644 clang-tools-extra/clang-tidy/cert/LimitedRandomnessCheck.h create mode 100644 clang-tools-extra/docs/clang-tidy/checks/cert-msc30-c.rst create mode 100644 clang-tools-extra/docs/clang-tidy/checks/cert-msc50-cpp.rst create mode 100644 clang-tools-extra/test/clang-tidy/cert-limited-randomness.c create mode 100644 clang-tools-extra/test/clang-tidy/cert-limited-randomness.cpp diff --git a/clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp b/clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp index c44d6eeb3914..71135378a29c 100644 --- a/clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp +++ b/clang-tools-extra/clang-tidy/cert/CERTTidyModule.cpp @@ -18,6 +18,7 @@ #include "../misc/ThrowByValueCatchByReferenceCheck.h" #include "CommandProcessorCheck.h" #include "FloatLoopCounter.h" +#include "LimitedRandomnessCheck.h" #include "SetLongJmpCheck.h" #include "StaticObjectExceptionCheck.h" #include "StrToNumCheck.h" @@ -53,6 +54,9 @@ public: "cert-err60-cpp"); CheckFactories.registerCheck( "cert-err61-cpp"); + // MSC + CheckFactories.registerCheck( + "cert-msc50-cpp"); // C checkers // DCL @@ -70,6 +74,9 @@ public: // ERR CheckFactories.registerCheck( "cert-err34-c"); + // MSC + CheckFactories.registerCheck( + "cert-msc30-c"); } ClangTidyOptions getModuleOptions() override { ClangTidyOptions Options; diff --git a/clang-tools-extra/clang-tidy/cert/CMakeLists.txt b/clang-tools-extra/clang-tidy/cert/CMakeLists.txt index a53ec2f65cf6..7a6b44a0272e 100644 --- a/clang-tools-extra/clang-tidy/cert/CMakeLists.txt +++ b/clang-tools-extra/clang-tidy/cert/CMakeLists.txt @@ -4,6 +4,7 @@ add_clang_library(clangTidyCERTModule CERTTidyModule.cpp CommandProcessorCheck.cpp FloatLoopCounter.cpp + LimitedRandomnessCheck.cpp SetLongJmpCheck.cpp StaticObjectExceptionCheck.cpp StrToNumCheck.cpp diff --git a/clang-tools-extra/clang-tidy/cert/LimitedRandomnessCheck.cpp b/clang-tools-extra/clang-tidy/cert/LimitedRandomnessCheck.cpp new file mode 100644 index 000000000000..807f1835fa61 --- /dev/null +++ b/clang-tools-extra/clang-tidy/cert/LimitedRandomnessCheck.cpp @@ -0,0 +1,40 @@ +//===--- LimitedRandomnessCheck.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 "LimitedRandomnessCheck.h" +#include "clang/AST/ASTContext.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" + +using namespace clang::ast_matchers; + +namespace clang { +namespace tidy { +namespace cert { + +void LimitedRandomnessCheck::registerMatchers(MatchFinder *Finder) { + Finder->addMatcher(callExpr(callee(functionDecl(namedDecl(hasName("::rand")), + parameterCountIs(0)))) + .bind("randomGenerator"), + this); +} + +void LimitedRandomnessCheck::check(const MatchFinder::MatchResult &Result) { + std::string msg = ""; + if (getLangOpts().CPlusPlus) + msg = "; use C++11 random library instead"; + + const auto *MatchedDecl = Result.Nodes.getNodeAs("randomGenerator"); + diag(MatchedDecl->getLocStart(), + "rand() has limited randomness" + msg); +} + +} // namespace cert +} // namespace tidy +} // namespace clang + diff --git a/clang-tools-extra/clang-tidy/cert/LimitedRandomnessCheck.h b/clang-tools-extra/clang-tidy/cert/LimitedRandomnessCheck.h new file mode 100644 index 000000000000..59d511cbab8f --- /dev/null +++ b/clang-tools-extra/clang-tidy/cert/LimitedRandomnessCheck.h @@ -0,0 +1,38 @@ +//===--- LimitedRandomnessCheck.h - clang-tidy-------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_LIMITED_RANDOMNESS_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_LIMITED_RANDOMNESS_H + +#include "../ClangTidy.h" + +namespace clang { +namespace tidy { +namespace cert { + +/// Pseudorandom number generators are not genuinely random. The result of the +/// std::rand() function makes no guarantees as to the quality of the random +/// sequence produced. +/// This check warns for the usage of std::rand() function. +/// +/// For the user-facing documentation see: +/// http://clang.llvm.org/extra/clang-tidy/checks/cert-msc50-cpp.html +class LimitedRandomnessCheck : public ClangTidyCheck { +public: + LimitedRandomnessCheck(StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context) {} + void registerMatchers(ast_matchers::MatchFinder *Finder) override; + void check(const ast_matchers::MatchFinder::MatchResult &Result) override; +}; + +} // namespace cert +} // namespace tidy +} // namespace clang + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_LIMITED_RANDOMNESS_H diff --git a/clang-tools-extra/docs/clang-tidy/checks/cert-msc30-c.rst b/clang-tools-extra/docs/clang-tidy/checks/cert-msc30-c.rst new file mode 100644 index 000000000000..97114188a476 --- /dev/null +++ b/clang-tools-extra/docs/clang-tidy/checks/cert-msc30-c.rst @@ -0,0 +1,7 @@ +.. title:: clang-tidy - cert-msc30-c + +cert-msc30-c +============ + +The cert-msc30-c check is an alias, please see +`cert-msc50-cpp `_ for more information. diff --git a/clang-tools-extra/docs/clang-tidy/checks/cert-msc50-cpp.rst b/clang-tools-extra/docs/clang-tidy/checks/cert-msc50-cpp.rst new file mode 100644 index 000000000000..c823e323f9f9 --- /dev/null +++ b/clang-tools-extra/docs/clang-tidy/checks/cert-msc50-cpp.rst @@ -0,0 +1,6 @@ +.. title:: clang-tidy - cert-msc50-cpp + +cert-msc50-cpp +============== + +Pseudorandom number generators use mathematical algorithms to produce a sequence of numbers with good statistical properties, but the numbers produced are not genuinely random. The ``std::rand()`` function takes a seed (number), runs a mathematical operation on it and returns the result. By manipulating the seed the result can be predictible. This check warns for the usage of ``std::rand()``. diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst index f9732352a339..c9069a7f1027 100644 --- a/clang-tools-extra/docs/clang-tidy/checks/list.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst @@ -18,6 +18,8 @@ Clang-Tidy Checks cert-err61-cpp (redirects to misc-throw-by-value-catch-by-reference) cert-fio38-c (redirects to misc-non-copyable-objects) cert-flp30-c + cert-msc30-c (redirects to cert-limited-randomness) + cert-msc50-cpp cert-oop11-cpp (redirects to misc-move-constructor-init) cppcoreguidelines-interfaces-global-init cppcoreguidelines-pro-bounds-array-to-pointer-decay diff --git a/clang-tools-extra/test/clang-tidy/cert-limited-randomness.c b/clang-tools-extra/test/clang-tidy/cert-limited-randomness.c new file mode 100644 index 000000000000..c8009b55ba82 --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/cert-limited-randomness.c @@ -0,0 +1,13 @@ +// RUN: %check_clang_tidy %s cert-msc30-c %t + +extern int rand(void); +int nonrand(); + +int cTest() { + int i = rand(); + // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: rand() has limited randomness [cert-msc30-c] + + int k = nonrand(); + + return 0; +} diff --git a/clang-tools-extra/test/clang-tidy/cert-limited-randomness.cpp b/clang-tools-extra/test/clang-tidy/cert-limited-randomness.cpp new file mode 100644 index 000000000000..845b7350de9f --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/cert-limited-randomness.cpp @@ -0,0 +1,28 @@ +// RUN: %check_clang_tidy %s cert-msc50-cpp %t + +int rand(); +int rand(int); + +namespace std { +using ::rand; +} + +namespace nonstd { + int rand(); +} + +void testFunction1() { + int i = std::rand(); + // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: rand() has limited randomness; use C++11 random library instead [cert-msc50-cpp] + + int j = ::rand(); + // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: rand() has limited randomness; use C++11 random library instead [cert-msc50-cpp] + + int k = rand(i); + + int l = nonstd::rand(); + + int m = rand(); + // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: rand() has limited randomness; use C++11 random library instead [cert-msc50-cpp] +} +