Linux Kernel Landlock LSM Null Dereference Vulnerability

A vulnerability in the Linux kernel's fscrypt implementation has been addressed. The issue arose because fscrypt_destroy_keyring() was called before all potentially encrypted inodes were evicted. Inodes used by the Landlock LSM remain in use until security_sb_delete() is called, creating a timing issue. This vulnerability could lead to a NULL dereference, but only when Landlock was applied to encrypted files.

Impact

Exploitation of this vulnerability could cause a NULL pointer dereference, leading to a crash of the kernel or the affected process.