cert-msc51-cpp¶
This check flags all pseudo-random number engines, engine adaptor
instantiations and srand() when initialized or seeded with default argument,
constant expression or any user-configurable type. 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. Ensure your random number generator is properly seeded and
MSC32-C. Properly seed pseudorandom number generators.
Examples:
void foo() {
std::mt19937 engine1; // Diagnose, always generate the same sequence
std::mt19937 engine2(1); // Diagnose
engine1.seed(); // Diagnose
engine2.seed(1); // Diagnose
std::time_t t;
engine1.seed(std::time(&t)); // Diagnose, system time might be controlled by user
int x = atoi(argv[1]);
std::mt19937 engine3(x); // Will not warn
}