The patch titled
Subject: docs: admin-guide: document the kernel.modprobe sysctl
has been added to the -mm tree. Its filename is
docs-admin-guide-document-the-kernelmodprobe-sysctl.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/docs-admin-guide-document-the-kernelmodprobe-sysctl.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/docs-admin-guide-document-the-kernelmodprobe-sysctl.patch
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------------------------------------------------------
From: Eric Biggers <ebiggers@xxxxxxxxxx>
Subject: docs: admin-guide: document the kernel.modprobe sysctl
Document the kernel.modprobe sysctl in the same place that all the other
kernel.* sysctls are documented. Make sure to mention how to use this
sysctl to completely disable module autoloading, and how this sysctl
relates to CONFIG_STATIC_USERMODEHELPER.
Link: http://lkml.kernel.org/r/20200312202552.241885-4-ebiggers@xxxxxxxxxx
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jeff Vander Stoep <jeffv@xxxxxxxxxx>
Cc: Jessica Yu <jeyu@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: NeilBrown <neilb@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/sysctl/kernel.rst | 25 +++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
--- a/Documentation/admin-guide/sysctl/kernel.rst~docs-admin-guide-document-the-kernelmodprobe-sysctl
+++ a/Documentation/admin-guide/sysctl/kernel.rst
@@ -49,7 +49,7 @@ show up in /proc/sys/kernel:
- kexec_load_disabled
- kptr_restrict
- l2cr [ PPC only ]
-- modprobe ==> Documentation/debugging-modules.txt
+- modprobe
- modules_disabled
- msg_next_id [ sysv ipc ]
- msgmax
@@ -444,6 +444,29 @@ l2cr: (PPC only)
This flag controls the L2 cache of G3 processor boards. If
0, the cache is disabled. Enabled if nonzero.
+modprobe:
+=========
+
+The path to the usermode helper for autoloading kernel modules, by
+default "/sbin/modprobe". This binary is executed when the kernel
+requests a module. For example, if userspace passes an unknown
+filesystem type "foo" to mount(), then the kernel will automatically
+request the module "fs-foo.ko" by executing this usermode helper.
+This usermode helper should insert the needed module into the kernel.
+
+This sysctl only affects module autoloading. It has no effect on the
+ability to explicitly insert modules.
+
+If this sysctl is set to the empty string, then module autoloading is
+completely disabled. The kernel will not try to execute a usermode
+helper at all, nor will it call the kernel_module_request LSM hook.
+
+If CONFIG_STATIC_USERMODEHELPER=y is set in the kernel configuration,
+then the configured static usermode helper overrides this sysctl,
+except that the empty string is still accepted to completely disable
+module autoloading as described above.
+
+Also see Documentation/debugging-modules.txt.
modules_disabled:
=================
_
Patches currently in -mm which might be from ebiggers@xxxxxxxxxx are
kmod-make-request_module-return-an-error-when-autoloading-is-disabled.patch
fs-filesystemsc-downgrade-user-reachable-warn_once-to-pr_warn_once.patch
docs-admin-guide-document-the-kernelmodprobe-sysctl.patch
selftests-kmod-test-disabling-module-autoloading.patch
