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chmod-calc Documentation RAM Adjusted Desktop Starter Previous page: chmod-calc Index page: Documentation Next page: RAM Adjusted Desktop Starter umask

Due to the umask hardening security feature, a usability issue may arise where file permissions are more restrictive than expected.

This guide demonstrates how to reproduce the issue and provides solutions to mitigate it.

Steps to reproduce

1. Create the file testfile.

touch -- testfile

2. Copy the file using cp.

sudo -- cp -- testfile /etc/testfile

3. View file permissions.

• A) ls
  • ls -la -- /etc/testfile
• B) chmod-calc:
  • chmod-calc /etc/testfile

Expected ls result

Readable by "others" ("public")

-rw-r--r-- 1 root root 0 May 11 10:54 /etc/testfile

Actual ls result

Unreadable by "others"

-rw-r----- 1 root root 0 May 11 10:54 /etc/testfile

Explanation

This behavior occurs because the file testfile was initially created with restrictive permissions, making it unreadable by "others". When the file is copied, those permissions are preserved by default.

The cp command retains the original file's mode (permissions) unless otherwise instructed. To prevent this, use the --no-preserve=mode option.

Solutions

Use cp with the --no-preserve=mode option to avoid inheriting the original permissions.

sudo -- cp --no-preserve=mode -- testfile /etc/testfile

Or, if the file has already been copied, adjust its permissions manually using chmod:

sudo -- chmod o+r -- /etc/testfile

chmod-calc Documentation RAM Adjusted Desktop Starter Previous page: chmod-calc Index page: Documentation Next page: RAM Adjusted Desktop Starter

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