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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: 93 rules found
cert
    Impact
      Clean code attribute
        1. "abort", "exit", "getenv" and "system" from <stdlib.h> should not be used

           Bug
        2. "atof", "atoi" and "atol" from <stdlib.h> should not be used

           Bug
        3. "setjmp" and "longjmp" should not be used

           Code Smell
        4. Reserved identifiers should not be defined or declared

           Code Smell
        5. In the definition of a function-like macro, each instance of a parameter shall be enclosed in parentheses, unless it is used as the operand of # or ##

           Code Smell
        6. Function-like macros should not be used

           Code Smell
        7. 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
        8. Function exit paths should have appropriate return values

           Bug
        9. The number of arguments passed to a function should match the number of parameters

           Bug
        10. Functions without parameters should be declared with parameter type "void"

           Code Smell
        11. Functions should not be defined with a variable number of arguments

           Code Smell
        12. The right-hand operands of && and || should not contain side effects

           Code Smell
        13. Increment (++) and decrement (--) operators should not be used in a method call or mixed with other operators in an expression

           Code Smell
        14. Bitwise operators should not be applied to signed operands

           Bug
        15. Boolean operations should not have numeric operands, and vice versa

           Bug
        16. Limited dependence should be placed on operator precedence

           Code Smell
        17. Objects with integer type should not be converted to objects with pointer type

           Bug
        18. A cast shall not remove any const or volatile qualification from the type of a pointer or reference

           Code Smell
        19. Signed and unsigned types should not be mixed in expressions

           Code Smell
        20. Array declarations should include an explicit size specification

           Code Smell
        21. Object and function types should be explicitly stated in their declarations and definitions

           Code Smell
        22. Functions should be declared explicitly

           Code Smell
        23. Literal suffix "L" for long integers shall be upper case

           Code Smell
        24. String literals with different prefixes should not be concatenated

           Bug
        25. Bit fields should be declared with appropriate types

           Code Smell
        26. Appropriate char types should be used for character and integer values

           Code Smell
        27. Identifiers should not be longer than 31 characters

           Code Smell
        28. Trigraphs should not be used

           Code Smell
        29. All uses of the #pragma directive should be documented

           Code Smell
        30. Names of well-known C standard library macros and functions should not be used as identifiers

           Code Smell
        31. Hard-coded secrets are security-sensitive

           Security Hotspot
        32. "sprintf" should not be used

           Security Hotspot
        33. Accessing files should not introduce TOCTOU vulnerabilities

           Vulnerability
        34. Macros should not be used as replacements for "typedef" and "using"

           Code Smell
        35. Using "tmpnam", "tmpnam_s" or "tmpnam_r" is security-sensitive

           Security Hotspot
        36. Using "strncpy" or "wcsncpy" is security-sensitive

           Security Hotspot
        37. Using "strncat" or "wcsncat" is security-sensitive

           Security Hotspot
        38. Using "strcat" or "wcscat" is security-sensitive

           Security Hotspot
        39. Using "strlen" or "wcslen" is security-sensitive

           Security Hotspot
        40. Using "strcpy" or "wcscpy" is security-sensitive

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

           Vulnerability
        42. Cipher algorithms should be robust

           Vulnerability
        43. Encryption algorithms should be used with secure mode and padding scheme

           Vulnerability
        44. User-defined types should not be passed as variadic arguments

           Bug
        45. Expanding archive files without controlling resource consumption is security-sensitive

           Security Hotspot
        46. Server certificates should be verified during SSL/TLS connections

           Vulnerability
        47. Integral operations should not overflow

           Bug
        48. Local variables and member data should not be volatile

           Code Smell
        49. Closed resources should not be accessed

           Bug
        50. Dynamically allocated memory should be released

           Bug
        51. Freed memory should not be used

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

           Bug
        53. Zero should not be a possible denominator

           Bug
        54. Format strings should be used correctly

           Code Smell
        55. "sizeof" should not be called on pointers

           Bug
        56. Declarations should not be empty

           Code Smell
        57. Multiline blocks should be enclosed in curly braces

           Code Smell
        58. "nonnull" parameters and return values of "returns_nonnull" functions should not be null

           Bug
        59. Setting loose POSIX file permissions is security-sensitive

           Security Hotspot
        60. Conditionally executed code should be reachable

           Bug
        61. Printf-style format strings should not lead to unexpected behavior at runtime

           Bug
        62. Null pointers should not be dereferenced

           Bug
        63. Using pseudorandom number generators (PRNGs) is security-sensitive

           Security Hotspot
        64. "for" loop counters should not have essentially floating type

           Bug
        65. Resources should be closed

           Bug
        66. Hard-coded passwords are security-sensitive

           Security Hotspot
        67. Comment styles "//" and "/* ... */" should not be mixed within a file

           Code Smell
        68. Obsolete POSIX functions should not be used

           Code Smell
        69. Code annotated as deprecated should not be used

           Code Smell
        70. Related "if/else if" statements should not have the same condition

           Bug
        71. Unused assignments should be removed

           Code Smell
        72. "restrict" should not be used

           Code Smell
        73. Pointers should not be cast to integral types

           Bug
        74. Identical expressions should not be used on both sides of a binary operator

           Bug
        75. All code should be reachable

           Bug
        76. "#pragma warning (default: ...)" should not be used

           Code Smell
        77. Multiple variables should not be declared on the same line

           Code Smell
        78. Variables should not be self-assigned

           Bug
        79. File names should comply with a naming convention

           Code Smell
        80. Octal values should not be used

           Code Smell
        81. Using hardcoded IP addresses is security-sensitive

           Security Hotspot
        82. "switch" statements should have "default" clauses

           Code Smell
        83. Switch cases should end with an unconditional "break" statement

           Code Smell
        84. "if ... else if" constructs should end with "else" clauses

           Code Smell
        85. Control structures should use curly braces

           Code Smell
        86. Unused function parameters should be removed

           Code Smell
        87. Assignments should not be made from within conditions

           Code Smell
        88. Variables should not be shadowed

           Code Smell
        89. Empty statements should be removed

           Code Smell
        90. "/*" and "//" should not be used within comments

           Code Smell
        91. Insecure functions should not be used

           Vulnerability
        92. Unused labels should be removed

           Code Smell
        93. Control should not be transferred into a complex logic block using a "goto" or a "switch" statement

           Code Smell

        Dynamically allocated memory should be released

        intentionality - complete
        reliability
        Bug
        • cwe
        • symbolic-execution
        • leak
        • denial-of-service
        • cert

        Memory allocated dynamically with calloc, malloc, realloc, or new should be released when it is not needed anymore. Failure to do so will result in a memory leak that could severely hinder application performance or abort it or the entire host machine.

        Why is this an issue?

        How can I fix it?

        More Info

        Memory is a limited resource shared between all the applications running on the same host machine.

        C and C++ do not automatically reclaim unused memory. The developer has to release the memory claimed for their application that is no longer needed. Unlike the stack that automatically allocates local variables on a function call and deallocates them on a function return, the heap offers no automatic memory management. The developer has to make sure to deallocate the memory they allocate dynamically on the heap.

        This rule raises an issue when memory is allocated dynamically and not freed within the same function.

        What is the potential impact?

        Neglecting to free the memory leads to a memory leak.

        The application that leaks memory will consume more and more of it over time, eventually claiming all the memory available on the host machine. When this happens and the system runs out of memory, it typically does one of the following:

        • The operating system (if any) terminates the application.
        • The operating system (if any) terminates some other application, and the problem reoccurs when the reclaimed memory gets used up by the leaking application.
        • The operating system (if any) starts offloading some of the memory pages to disk and slows down some memory accesses by orders of magnitude.
        • The entire system crashes as a whole and reboots automatically or hangs waiting for a manual reboot.

        Moreover, memory leaks can help an attacker to take over the system. An attacker could use a memory leak to fill the memory with malicious code. This facilitates remote code execution through another chained vulnerability.

        Even if the attacker cannot take over the system she can intentionally trigger the condition leading to a memory leak to make use of the issue above and cause denial-of-service (DoS) of the system.

        A memory leak can have a significant impact on the energy footprint of an application.

        • If an application demands more memory than necessary, the user will have to install more memory banks than necessary. Each memory bank consumes additional power.
        • As the application continues to reserve more and more memory, it places an increased load on the memory management subsystem. This increased load can lead to a larger computation demand, which in turn translates to higher power consumption by the CPU.

        Finally, memory leaks degrade the user experience. The user often experiences a system slowdown caused by the uncontrolled memory use of an application. Delayed response time, system freezes, and crashes degrade the user experience and discourage the further use of the application.

        Exceptions

        If a function returns a pointer to the caller or stores it in an external structure, this pointer is said to escape (it is now accessible outside of function, and no longer local to it). This includes storing the pointer in a static or global variable, passing it to a function that can potentially do that, or returning the pointer directly or as part of an aggregate object.

        The memory pointed to by an escaping pointer might be used somewhere else in the program. For that reason, the analyzer cannot proclaim a leak for an escaping pointer by only looking at a function scope.

        While in some cases the leak might be detectable in the scope of a caller, in others, the analyzer would need to simulate the entire program to verify that the memory is not used anywhere, which is not feasible.

        For this technical reason, this rule often ignores escaping pointers.

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          Available Since
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