Information
RHEL 10 must enable kernel parameters to enforce discretionary access control (DAC) on hardlinks.
GROUP ID: V-281309RULE ID: SV-281309r1184631
By enabling the "fs.protected_hardlinks" kernel parameter, users can no longer create soft or hard links to files they do not own. Disallowing such hardlinks mitigates vulnerabilities based on insecure file systems accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of open() or creat().
Satisfies: SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000324-GPOS-00125
Solution
Configure RHEL 10 to enable DAC on hardlinks.
Create a drop-in if it does not already exist:
$ sudo vi /etc/sysctl.d/99-fs_protected_hardlinks.conf
Add the following to the file:
fs.protected_hardlinks = 1
Reload settings from all system configuration files with the following command:
$ sudo sysctl --system