mirror of
https://github.com/torvalds/linux
synced 2024-07-23 11:39:11 +00:00
0860b72d53
Loadpin cmdline interface "enabled" has been renamed to "enforce" for a long time, but the User Description Document was not updated. (Meaning unchanged) And kernel_read_file* were moved from linux/fs.h to its own linux/kernel_read_file.h include file. So update that change here. Signed-off-by: Jiele zhao <unclexiaole@gmail.com> Link: https://lore.kernel.org/r/20210308020358.102836-1-unclexiaole@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
32 lines
1.6 KiB
ReStructuredText
32 lines
1.6 KiB
ReStructuredText
=======
|
|
LoadPin
|
|
=======
|
|
|
|
LoadPin is a Linux Security Module that ensures all kernel-loaded files
|
|
(modules, firmware, etc) all originate from the same filesystem, with
|
|
the expectation that such a filesystem is backed by a read-only device
|
|
such as dm-verity or CDROM. This allows systems that have a verified
|
|
and/or unchangeable filesystem to enforce module and firmware loading
|
|
restrictions without needing to sign the files individually.
|
|
|
|
The LSM is selectable at build-time with ``CONFIG_SECURITY_LOADPIN``, and
|
|
can be controlled at boot-time with the kernel command line option
|
|
"``loadpin.enforce``". By default, it is enabled, but can be disabled at
|
|
boot ("``loadpin.enforce=0``").
|
|
|
|
LoadPin starts pinning when it sees the first file loaded. If the
|
|
block device backing the filesystem is not read-only, a sysctl is
|
|
created to toggle pinning: ``/proc/sys/kernel/loadpin/enabled``. (Having
|
|
a mutable filesystem means pinning is mutable too, but having the
|
|
sysctl allows for easy testing on systems with a mutable filesystem.)
|
|
|
|
It's also possible to exclude specific file types from LoadPin using kernel
|
|
command line option "``loadpin.exclude``". By default, all files are
|
|
included, but they can be excluded using kernel command line option such
|
|
as "``loadpin.exclude=kernel-module,kexec-image``". This allows to use
|
|
different mechanisms such as ``CONFIG_MODULE_SIG`` and
|
|
``CONFIG_KEXEC_VERIFY_SIG`` to verify kernel module and kernel image while
|
|
still use LoadPin to protect the integrity of other files kernel loads. The
|
|
full list of valid file types can be found in ``kernel_read_file_str``
|
|
defined in ``include/linux/kernel_read_file.h``.
|