SonarSource Rules
  • Products

    In-IDE

    Code Quality and Security in your IDE with SonarQube Ide

    IDE extension that lets you fix coding issues before they exist!

    Discover SonarQube for IDE

    SaaS

    Code Quality and Security in the cloud with SonarQube Cloud

    Setup is effortless and analysis is automatic for most languages

    Discover SonarQube Cloud

    Self-Hosted

    Code Quality and Security Self-Hosted with SonarQube Server

    Fast, accurate analysis; enterprise scalability

    Discover SonarQube Server
  • SecretsSecrets
  • ABAPABAP
  • AnsibleAnsible
  • ApexApex
  • AzureResourceManagerAzureResourceManager
  • CC
  • C#C#
  • C++C++
  • CloudFormationCloudFormation
  • COBOLCOBOL
  • CSSCSS
  • DartDart
  • DockerDocker
  • FlexFlex
  • GitHub ActionsGitHub Actions
  • GoGo
  • HTMLHTML
  • JavaJava
  • JavaScriptJavaScript
  • JSONJSON
  • JCLJCL
  • KotlinKotlin
  • KubernetesKubernetes
  • Objective CObjective C
  • PHPPHP
  • PL/IPL/I
  • PL/SQLPL/SQL
  • PythonPython
  • RPGRPG
  • RubyRuby
  • RustRust
  • ScalaScala
  • SwiftSwift
  • TerraformTerraform
  • TextText
  • TypeScriptTypeScript
  • T-SQLT-SQL
  • VB.NETVB.NET
  • VB6VB6
  • XMLXML
  • YAMLYAML
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
 
Tags
    Impact
      Clean code attribute
        1. Hard-coded secrets are security-sensitive

           Security Hotspot
        2. "sprintf" should not be used

           Security Hotspot
        3. Changing working directories without verifying the success is security-sensitive

           Security Hotspot
        4. Setting capabilities is security-sensitive

           Security Hotspot
        5. Using "tmpnam", "tmpnam_s" or "tmpnam_r" is security-sensitive

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

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

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

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

           Security Hotspot
        10. Changing directories improperly when using "chroot" is security-sensitive

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

           Security Hotspot
        12. Using publicly writable directories is security-sensitive

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

           Security Hotspot
        14. Expanding archive files without controlling resource consumption is security-sensitive

           Security Hotspot
        15. Using weak hashing algorithms is security-sensitive

           Security Hotspot
        16. Setting loose POSIX file permissions is security-sensitive

           Security Hotspot
        17. Using pseudorandom number generators (PRNGs) is security-sensitive

           Security Hotspot
        18. Hard-coded passwords are security-sensitive

           Security Hotspot
        19. Using hardcoded IP addresses is security-sensitive

           Security Hotspot

        "sprintf" should not be used

        intentionality - complete
        security
        Security Hotspot
        • cwe
        • cert

        When using sprintf , it’s up to the developer to make sure the size of the buffer to be written to is large enough to avoid buffer overflows. Buffer overflows can cause the program to crash at a minimum. At worst, a carefully crafted overflow can cause malicious code to be executed.

        Ask Yourself Whether

        • if the provided buffer is large enough for the result of any possible call to the sprintf function (including all possible format strings and all possible additional arguments).

        There is a risk if you answered no to the above question.

        Recommended Secure Coding Practices

        There are fundamentally safer alternatives. snprintf is one of them. It takes the size of the buffer as an additional argument, preventing the function from overflowing the buffer.

        • Use snprintf instead of sprintf. The slight performance overhead can be afforded in a vast majority of projects.
        • Check the buffer size passed to snprintf.

        If you are working in C++, other safe alternative exist:

        • std::string should be the prefered type to store strings
        • You can format to a string using std::ostringstream
        • Since C++20, std::format is also available to format strings

        Sensitive Code Example

        sprintf(str, "%s", message);   // Sensitive: `str` buffer size is not checked and it is vulnerable to overflows
        

        Compliant Solution

        snprintf(str, sizeof(str), "%s", message); // Prevent overflows by enforcing a maximum size for `str` buffer
        

        Exceptions

        It is a very common and acceptable pattern to compute the required size of the buffer with a call to snprintf with the same arguments into an empty buffer (this will fail, but return the necessary size), then to call sprintf as the bound check is not needed anymore. Note that 1 needs to be added by the size reported by snprintf to account for the terminal null character.

        size_t buflen = snprintf(0, 0, "%s", message);
        char* buf = malloc(buflen + 1); // For the final 0
        sprintf(buf, "%s", message);{code}
        

        See

        • OWASP - Top 10 2021 Category A6 - Vulnerable and Outdated Components
        • OWASP - Top 10 2017 Category A9 - Using Components with Known Vulnerabilities
        • CWE - CWE-676 - Use of Potentially Dangerous Function
        • CWE - CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer
        • STIG Viewer - Application Security and Development: V-222612 - The application must not be vulnerable to overflow attacks.
          Available In:
        • SonarQube IdeCatch issues on the fly,
          in your IDE
        • SonarQube CloudDetect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories
        • SonarQube ServerAnalyze code in your
          on-premise CI
          Developer Edition
          Available Since
          9.1

        © 2008-2025 SonarSource SA. All rights reserved.

        Privacy Policy | Cookie Policy | Terms of Use