Linux Kernel Landlock ID Range Handling Vulnerability

A vulnerability in the Linux kernel's Landlock security module has been addressed. The issue arose because the function 'get_id_range()' required a positive value as its first argument, while 'get_random_u8()' could return zero. This discrepancy led to a warning during KUnit testing. The vulnerability was resolved by modifying 'get_id_range()' to ensure it receives a valid positive value. The fix was validated by running the test 1000 times in a loop, successfully passing all iterations without errors.

Impact

The vulnerability could have led to improper handling of ID generation, potentially causing issues in scenarios where unique IDs are critical.

Reproduction

The vulnerability can be reproduced by running the Landlock KUnit tests. The test 'test_range2_rand16' will trigger the warning by passing a zero value, which is not accepted by the 'get_id_range()' function. This can be automated by looping the test execution 1000 times.

Remediation

Users can apply the latest patch available in the Linux kernel stable tree to address this vulnerability.