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Resolve vulnerability: Potential time of check time of use vulnerability (chmod)

Michael Friedrich requested to merge remediate/potential-time-of-check-time-of-use-vulnerability--chmod-D20240308T013419 into main

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Description:

Usage of the chmod function call hints at a potential Time Of Check Time Of Use (TOCTOU) vulnerability. An attacker may be able to modify the file being specified by the chmod function prior to the chmod function being called. Since chmod will resolve symbolic links, an attacker may be able to exploit this fact to have files outside of their control modified.

It is recommended that the fchmod function be used instead since this function takes a file descriptor instead of a file. Ensure the opened file descriptor is pointing to the correct file or directory prior to executing fchmod or any other file based operations.

For more information please see: https://wiki.sei.cmu.edu/confluence/display/c/FIO01-C.+Be+careful+using+functions+that+use+file+names+for+identification

  • Severity: critical
  • Confidence: unknown
  • Location: src/mem.c:38

Identifiers:

  • A5:2017 - Broken Access Control
  • A01:2021 - Broken Access Control
  • Flawfinder - chmod
  • flawfinder.chmod-1
  • CWE-362

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