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C

C static code analysis

Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C code

  • All rules 315
  • Vulnerability13
  • Bug76
  • Security Hotspot19
  • Code Smell207

  • Quick Fix 19
Filtered: 35 rules found
symbolic-execution
    Impact
      Clean code attribute
        1. The address of an automatic object should not be assigned to another object that may persist after the first object has ceased to exist

           Bug
        2. Variables should be initialized before use

           Bug
        3. Variables should not be accessed outside of their scope

           Bug
        4. Account validity should be verified when authenticating users with PAM

           Vulnerability
        5. Changing directories improperly when using "chroot" is security-sensitive

           Security Hotspot
        6. POSIX functions should not be called with arguments that trigger buffer overflows

           Vulnerability
        7. Server hostnames should be verified during SSL/TLS connections

           Vulnerability
        8. "pthread_mutex_t" should be unlocked in the reverse order they were locked

           Bug
        9. Only valid arguments should be passed to UNIX/POSIX functions

           Code Smell
        10. "pthread_mutex_t" should be properly initialized and destroyed

           Bug
        11. "pthread_mutex_t" should not be locked when already locked, or unlocked when already unlocked

           Bug
        12. Only valid arguments should be passed to stream functions

           Code Smell
        13. Using publicly writable directories is security-sensitive

           Security Hotspot
        14. Using clear-text protocols is security-sensitive

           Security Hotspot
        15. Blocking functions should not be called inside critical sections

           Code Smell
        16. Return value of "setuid" family of functions should always be checked

           Code Smell
        17. Size of variable length arrays should be greater than zero

           Code Smell
        18. "mktemp" family of functions templates should have at least six trailing "X"s

           Code Smell
        19. Appropriate size arguments should be passed to "strncat" and "strlcpy"

           Code Smell
        20. Server certificates should be verified during SSL/TLS connections

           Vulnerability
        21. Weak SSL/TLS protocols should not be used

           Vulnerability
        22. Integral operations should not overflow

           Bug
        23. Parameter values should be appropriate

           Bug
        24. Stack allocated memory and non-owned memory should not be freed

           Bug
        25. Closed resources should not be accessed

           Bug
        26. Dynamically allocated memory should be released

           Bug
        27. Freed memory should not be used

           Bug
        28. Memory locations should not be released more than once

           Bug
        29. Memory access should be explicitly bounded to prevent buffer overflows

           Bug
        30. Zero should not be a possible denominator

           Bug
        31. XML parsers should not be vulnerable to XXE attacks

           Vulnerability
        32. "nonnull" parameters and return values of "returns_nonnull" functions should not be null

           Bug
        33. Null pointers should not be dereferenced

           Bug
        34. Resources should be closed

           Bug
        35. Unused assignments should be removed

           Code Smell

        Only valid arguments should be passed to UNIX/POSIX functions

        intentionality - logical
        maintainability
        Code Smell
        • symbolic-execution
        • suspicious

        Passing invalid arguments to UNIX/POSIX functions may result in undefined behavior.

        Why is this an issue?

        What is the potential impact?

        How can I fix it?

        More Info

        Many UNIX/POSIX functions put certain constraints on the values of their parameters. The behavior for some of those UNIX/POSIX functions is not defined but instead, their behavior is implementation-defined, if one passes incorrectly constrained parameters. This may lead to undefined behavior depending on a function’s concrete implementation. The constraints include the following:

        • Allocation sizes of calloc, malloc, realloc, reallocf, alloca and valloc must be strictly positive
        • open and openat should be called with a flag that contains one of the access modes: O_RDONLY, O_WRONLY, or O_RDWR
        • open and openat with flag O_CREAT should be called with a third argument
        • The O_EXCL flag should be used with O_CREAT
        • The first argument of pthread_once should not have automatic storage duration and should be initialized by the constant PTHREAD_ONCE_INIT

        Failing to pass correctly constrained parameters can result in undefined behavior.

        // Depending on the implementation, either NULL is returned, or the behavior is
        // as if the passed size parameter were a non-zero value, except that accesses
        // of the returned pointer result in undefined behavior.
        void *mem = alloca(0); // May result in undefined behavior.
        
        int fd = open("example.txt", O_ APPEND); // Access mode is missing, may result in undefined behavior.
        
        // Third argument should be used to specify the file's access permissions.
        int fd_1 = open("another_example.txt", O_CREAT); // May result in undefined behavior.
        
        // Since `O_EXCL` prevents file creation if it already exists, the flag for
        // file creation `O_CREAT` should be used in combination with `O_EXCL`.
        int fd_3 = open("further_example.txt", O_EXCL); // `O_CREAT` flag is missing, may result in undefined behavior.
        
        int counter = 0;
        
        void inc_counter() { ++counter; }
        
        void bar() {
          // May trigger undefined behavior, because `once_control`'s storage duration
          // is automatic. `counter` might be incremented with each call to `bar`.
          pthread_once_t once_control = PTHREAD_ONCE_INIT;
          pthread_once(&once_control, &inc_counter); // May result in undefined behavior.
        }
        
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