| Kees Cook | 9b09155 | 2016-04-20 15:46:28 -0700 | [diff] [blame] | 1 | LoadPin is a Linux Security Module that ensures all kernel-loaded files |
| 2 | (modules, firmware, etc) all originate from the same filesystem, with |
| 3 | the expectation that such a filesystem is backed by a read-only device |
| 4 | such as dm-verity or CDROM. This allows systems that have a verified |
| 5 | and/or unchangeable filesystem to enforce module and firmware loading |
| 6 | restrictions without needing to sign the files individually. |
| 7 | |
| 8 | The LSM is selectable at build-time with CONFIG_SECURITY_LOADPIN, and |
| 9 | can be controlled at boot-time with the kernel command line option |
| 10 | "loadpin.enabled". By default, it is enabled, but can be disabled at |
| 11 | boot ("loadpin.enabled=0"). |
| 12 | |
| 13 | LoadPin starts pinning when it sees the first file loaded. If the |
| 14 | block device backing the filesystem is not read-only, a sysctl is |
| 15 | created to toggle pinning: /proc/sys/kernel/loadpin/enabled. (Having |
| 16 | a mutable filesystem means pinning is mutable too, but having the |
| 17 | sysctl allows for easy testing on systems with a mutable filesystem.) |