summaryrefslogtreecommitdiffstats
path: root/Documentation/admin-guide/LSM/LoadPin.rst
diff options
context:
space:
mode:
authorKees Cook <kees+treewide@kernel.org>2026-09-02 15:31:14 -0700
committerKees Cook <kees@kernel.org>2026-09-04 21:37:00 -0700
commit3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch)
treec65086f9bdcd48c6360fb7cb4598bca084da1f32 /Documentation/admin-guide/LSM/LoadPin.rst
downloadlinux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.tar.gz
linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.zip
treewide: refresh kmalloc_obj() conversionsgrafted
This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook <kees+treewide@kernel.org>
Diffstat (limited to 'Documentation/admin-guide/LSM/LoadPin.rst')
-rw-r--r--Documentation/admin-guide/LSM/LoadPin.rst31
1 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/admin-guide/LSM/LoadPin.rst b/Documentation/admin-guide/LSM/LoadPin.rst
new file mode 100644
index 000000000..dd3ca68b5
--- /dev/null
+++ b/Documentation/admin-guide/LSM/LoadPin.rst
@@ -0,0 +1,31 @@
+=======
+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``.