forked from OSchip/llvm-project
41 lines
1.3 KiB
ReStructuredText
41 lines
1.3 KiB
ReStructuredText
.. title:: clang-tidy - cert-msc51-cpp
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cert-msc51-cpp
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==============
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This check flags all pseudo-random number engines, engine adaptor
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instantiations and ``srand()`` when initialized or seeded with default argument,
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constant expression or any user-configurable type. Pseudo-random number
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engines seeded with a predictable value may cause vulnerabilities e.g. in
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security protocols.
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This is a CERT security rule, see
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`MSC51-CPP. Ensure your random number generator is properly seeded
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<https://wiki.sei.cmu.edu/confluence/display/cplusplus/MSC51-CPP.+Ensure+your+random+number+generator+is+properly+seeded>`_ and
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`MSC32-C. Properly seed pseudorandom number generators
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<https://wiki.sei.cmu.edu/confluence/display/c/MSC32-C.+Properly+seed+pseudorandom+number+generators>`_.
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Examples:
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.. code-block:: c++
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void foo() {
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std::mt19937 engine1; // Diagnose, always generate the same sequence
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std::mt19937 engine2(1); // Diagnose
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engine1.seed(); // Diagnose
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engine2.seed(1); // Diagnose
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std::time_t t;
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engine1.seed(std::time(&t)); // Diagnose, system time might be controlled by user
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int x = atoi(argv[1]);
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std::mt19937 engine3(x); // Will not warn
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}
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Options
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-------
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.. option:: DisallowedSeedTypes
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A comma-separated list of the type names which are disallowed.
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Default values are ``time_t``, ``std::time_t``.
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