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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

        Using hardcoded IP addresses is security-sensitive

        responsibility - trustworthy
        security
        Security Hotspot
        • cert

        Hardcoding IP addresses is security-sensitive. It has led in the past to the following vulnerabilities:

        • CVE-2006-5901
        • CVE-2005-3725

        Today’s services have an ever-changing architecture due to their scaling and redundancy needs. It is a mistake to think that a service will always have the same IP address. When it does change, the hardcoded IP will have to be modified too. This will have an impact on the product development, delivery, and deployment:

        • The developers will have to do a rapid fix every time this happens, instead of having an operation team change a configuration file.
        • It misleads to use the same address in every environment (dev, sys, qa, prod).

        Last but not least it has an effect on application security. Attackers might be able to decompile the code and thereby discover a potentially sensitive address. They can perform a Denial of Service attack on the service, try to get access to the system, or try to spoof the IP address to bypass security checks. Such attacks can always be possible, but in the case of a hardcoded IP address solving the issue will take more time, which will increase an attack’s impact.

        Ask Yourself Whether

        The disclosed IP address is sensitive, e.g.:

        • Can give information to an attacker about the network topology.
        • It’s a personal (assigned to an identifiable person) IP address.

        There is a risk if you answered yes to any of these questions.

        Recommended Secure Coding Practices

        Don’t hard-code the IP address in the source code, instead make it configurable with environment variables, configuration files, or a similar approach. Alternatively, if confidentially is not required a domain name can be used since it allows to change the destination quickly without having to rebuild the software.

        Sensitive Code Example

        dbi_conn conn = dbi_conn_new("mysql");
        string host = "10.10.0.1"; // Sensitive
        dbi_conn_set_option(conn, "host", host.c_str());
        dbi_conn_set_option(conn, "host", "10.10.0.1"); // Sensitive
        

        Compliant Solution

        dbi_conn conn = dbi_conn_new("mysql");
        string host = getDatabaseHost(); // Compliant
        dbi_conn_set_option(conn, "host", host.c_str()); // Compliant
        

        Exceptions

        No issue is reported for the following cases because they are not considered sensitive:

        • Loopback addresses 127.0.0.0/8 in CIDR notation (from 127.0.0.0 to 127.255.255.255)
        • Broadcast address 255.255.255.255
        • Non-routable address 0.0.0.0
        • Strings of the form 2.5.<number>.<number> as they often match Object Identifiers (OID)
        • Addresses in the ranges 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24, reserved for documentation purposes by RFC 5737
        • Addresses in the range 2001:db8::/32, reserved for documentation purposes by RFC 3849

        See

        • OWASP - Top 10 2021 Category A1 - Broken Access Control
        • OWASP - Top 10 2017 Category A3 - Sensitive Data Exposure
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