Rule S2612: Setting loose POSIX file permissions is security-sensitive

General

• if a mode can not be resolved no issue should be raised

chmod, lchmod, fchmod

If constants are used, should raise when one of the following is present:

• stat.S_IRWXO
• stat.S_IROTH
• stat.S_IWOTH
• stat.S_IXOTH

If numerical, should raise when the mode as decimal value modulo 8 does not equal zero (mode%8 != 0). Normally people use octal to specify the mode but this is not necessary.

Noncompliant Code Example

os.chmod("foo", 0o777)  # Sensitive
os.chmod("foo", 0o007)  # Sensitive
os.chmod("foo", 511)  # Sensitive
os.chmod("foo", 750)  # Sensitive
os.lchmod("foo", 0o777)  # Sensitive
os.fchmod(fd, 0o777)  # Sensitive

Compliant Code Example

os.chmod("foo", 0)  # Compliant
os.chmod("foo", 0o750)  # Compliant
os.lchmod("foo", 0o770)  # Compliant
os.fchmod(fd, 0o770)  # Compliant
os.chmod("foo", mode)  # Compliant (unknown)

umask

Should raise when the mask as decimal value modulo 8 does not equal seven (mode%8 != 7). Normally people use octal to specify the mask but this is not necessary.

Noncompliant Code Example

os.umask(0)  # Sensitive
os.umask(0o750)  # Sensitive

Compliant Code Example

os.umask(0o777)  # Compliant
os.umask(0o007)  # Compliant
os.umask(mask)  # Compliant (unknown)

Code samples: https://github.com/SonarSource/security-expected-issues/tree/master/python/rules/hotspots/RSPEC-2612