[PATCH] D44143: Create properly seeded random generator check

[Borsik Gábor via Phabricator via cfe-commits]

boga95 created this revision.
boga95 added a reviewer: clang-tools-extra.
boga95 added a project: clang-tools-extra.
Herald added subscribers: cfe-commits, mgorny.

This check flags all pseudo-random number engines and engine adaptors instantiations when it initialized or seeded with default argument or a constant expression. Pseudo-random number engines seeded with a predictable value may cause vulnerabilities e.g. in security protocols.
This is a CERT security rule, see MSC51-CPP <https://wiki.sei.cmu.edu/confluence/display/cplusplus/MSC51-CPP.+Ensure+your+random+number+generator+is+properly+seeded>.

Example:

  void foo() {
      std::mt19937 engine1; // Bad, always generate the same sequence
      std::mt19937 engine2(1); // Bad
      engine1.seed(); // Bad
      engine2.seed(1); // Bad
      
      std::time_t t;
      engine1.seed(std::time(&t)); // Bad, system time might be controlled by user
  
      std::random_device dev;
      std::mt19937 engine3(dev()); // Good
  }


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D44143

Files:
  clang-tidy/cert/CERTTidyModule.cpp
  clang-tidy/cert/CMakeLists.txt
  clang-tidy/cert/ProperlySeededRandomGeneratorCheck.cpp
  clang-tidy/cert/ProperlySeededRandomGeneratorCheck.h
  docs/ReleaseNotes.rst
  docs/clang-tidy/checks/cert-properly-seeded-random-generator.rst
  test/clang-tidy/cert-properly-seeded-random-generator.cpp

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