Informationdevice-mapper-verity (dm-verity) kernel feature feature provides transparent integrity checking of block devices using a cryptographic digest provided by the kernel crypto API. When a dm-verity device is configured, it is expected that the caller has been authenticated in some way (cryptographic signatures, etc). After instantiation, all hashes will be verified on-demand during disk access. If they cannot be verified up to the root node of the tree, the root hash, then the I/O will fail. This should detect tampering with any data on the device and the hash data.
The Container-Optimized OS root filesystem is always mounted as read-only. Additionally, its checksum is computed at build time and verified by the kernel on each boot. This mechanism prevents against attackers from 'owning' the machine through permanent local changes.
SolutionAn OS image update that has the dm-verity enabled kernel is required.