9ee16daa47
* Update JSON schema to include STIG ASD 2023-06-08 mapping * Update rules to add STIG metadata mappings --------- Co-authored-by: Loris Sierra <loris.sierra@sonarsource.com>
86 lines
2.2 KiB
Plaintext
86 lines
2.2 KiB
Plaintext
include::../common/description.adoc[]
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== Why is this an issue?
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include::../common/rationale.adoc[]
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=== What is the potential impact?
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include::../common/impact/rationale.adoc[]
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include::../common/impact/code_execution.adoc[]
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include::../common/impact/privilege_escalation.adoc[]
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include::../common/impact/dos.adoc[]
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== How to fix it
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include::../common/how-to-fix/rationale.adoc[]
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=== Code examples
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==== Noncompliant code example
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The following code sample is susceptible to a race condition attack because it
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checks a file exists strictly before it opens it for writing.
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[source,cpp,diff-id=1,diff-type=noncompliant]
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----
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FILE *fopen_if_not_exists(const char *file) {
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if (access(file, F_OK) == -1 && errno == ENOENT) {
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FILE *f = fopen(file, "w"); // Noncompliant
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return f;
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}
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return nullptr;
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}
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----
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==== Compliant solution
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[source,cpp,diff-id=1,diff-type=compliant]
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----
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FILE *fopen_if_not_exists(const char *file) {
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FILE *f = fopen(file, "wx");
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return f;
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}
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----
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=== How does this work?
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Here, the compliant code example uses an atomic operation to open the file and
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check for its existence beforehand.
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== Resources
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=== Documentation
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* Carnegie Mellon University Software Engineering Institure - https://wiki.sei.cmu.edu/confluence/display/c/FIO45-C.+Avoid+TOCTOU+race+conditions+while+accessing+files[FIO45-C. - Avoid TOCTOU race conditions while accessing files]
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=== Standards
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* OWASP - https://owasp.org/Top10/A01_2021-Broken_Access_Control/[Top 10 2021 Category A1 - Broken Access Control]
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* OWASP - https://owasp.org/www-project-top-ten/2017/A5_2017-Broken_Access_Control[Top 10 2017 Category A5 - Broken Access Control]
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* CWE - https://cwe.mitre.org/data/definitions/367[CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition]
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* STIG Viewer - https://stigviewer.com/stig/application_security_and_development/2023-06-08/finding/V-222567[Application Security and Development: V-222567] - The application must not be vulnerable to race conditions.
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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include::../message.adoc[]
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'''
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== Comments And Links
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(visible only on this page)
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include::../comments-and-links.adoc[]
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endif::env-github,rspecator-view[]
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