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- # SPDX-License-Identifier: GPL-2.0-only
- menuconfig MODULES
- bool "Enable loadable module support"
- modules
- help
- Kernel modules are small pieces of compiled code which can
- be inserted in the running kernel, rather than being
- permanently built into the kernel. You use the "modprobe"
- tool to add (and sometimes remove) them. If you say Y here,
- many parts of the kernel can be built as modules (by
- answering M instead of Y where indicated): this is most
- useful for infrequently used options which are not required
- for booting. For more information, see the man pages for
- modprobe, lsmod, modinfo, insmod and rmmod.
- If you say Y here, you will need to run "make
- modules_install" to put the modules under /lib/modules/
- where modprobe can find them (you may need to be root to do
- this).
- If unsure, say Y.
- if MODULES
- config MODULE_FORCE_LOAD
- bool "Forced module loading"
- default n
- help
- Allow loading of modules without version information (ie. modprobe
- --force). Forced module loading sets the 'F' (forced) taint flag and
- is usually a really bad idea.
- config MODULE_UNLOAD
- bool "Module unloading"
- help
- Without this option you will not be able to unload any
- modules (note that some modules may not be unloadable
- anyway), which makes your kernel smaller, faster
- and simpler. If unsure, say Y.
- config MODULE_FORCE_UNLOAD
- bool "Forced module unloading"
- depends on MODULE_UNLOAD
- help
- This option allows you to force a module to unload, even if the
- kernel believes it is unsafe: the kernel will remove the module
- without waiting for anyone to stop using it (using the -f option to
- rmmod). This is mainly for kernel developers and desperate users.
- If unsure, say N.
- config MODULE_UNLOAD_TAINT_TRACKING
- bool "Tainted module unload tracking"
- depends on MODULE_UNLOAD
- default n
- help
- This option allows you to maintain a record of each unloaded
- module that tainted the kernel. In addition to displaying a
- list of linked (or loaded) modules e.g. on detection of a bad
- page (see bad_page()), the aforementioned details are also
- shown. If unsure, say N.
- config MODVERSIONS
- bool "Module versioning support"
- help
- Usually, you have to use modules compiled with your kernel.
- Saying Y here makes it sometimes possible to use modules
- compiled for different kernels, by adding enough information
- to the modules to (hopefully) spot any changes which would
- make them incompatible with the kernel you are running. If
- unsure, say N.
- config ASM_MODVERSIONS
- bool
- default HAVE_ASM_MODVERSIONS && MODVERSIONS
- help
- This enables module versioning for exported symbols also from
- assembly. This can be enabled only when the target architecture
- supports it.
- config MODULE_SRCVERSION_ALL
- bool "Source checksum for all modules"
- help
- Modules which contain a MODULE_VERSION get an extra "srcversion"
- field inserted into their modinfo section, which contains a
- sum of the source files which made it. This helps maintainers
- see exactly which source was used to build a module (since
- others sometimes change the module source without updating
- the version). With this option, such a "srcversion" field
- will be created for all modules. If unsure, say N.
- config MODULE_SCMVERSION
- bool "SCM version for modules"
- depends on LOCALVERSION_AUTO
- help
- This enables the module attribute "scmversion" which can be used
- by developers to identify the SCM version of a given module, e.g.
- git sha1 or hg sha1. The SCM version can be queried by modinfo or
- via the sysfs node: /sys/modules/MODULENAME/scmversion. This is
- useful when the kernel or kernel modules are updated separately
- since that causes the vermagic of the kernel and the module to
- differ.
- If unsure, say N.
- config MODULE_SIG
- bool "Module signature verification"
- select MODULE_SIG_FORMAT
- help
- Check modules for valid signatures upon load: the signature
- is simply appended to the module. For more information see
- <file:Documentation/admin-guide/module-signing.rst>.
- Note that this option adds the OpenSSL development packages as a
- kernel build dependency so that the signing tool can use its crypto
- library.
- You should enable this option if you wish to use either
- CONFIG_SECURITY_LOCKDOWN_LSM or lockdown functionality imposed via
- another LSM - otherwise unsigned modules will be loadable regardless
- of the lockdown policy.
- !!!WARNING!!! If you enable this option, you MUST make sure that the
- module DOES NOT get stripped after being signed. This includes the
- debuginfo strip done by some packagers (such as rpmbuild) and
- inclusion into an initramfs that wants the module size reduced.
- config MODULE_SIG_FORCE
- bool "Require modules to be validly signed"
- depends on MODULE_SIG
- help
- Reject unsigned modules or signed modules for which we don't have a
- key. Without this, such modules will simply taint the kernel.
- config MODULE_SIG_PROTECT
- bool "Android GKI module protection"
- depends on MODULE_SIG && !MODULE_SIG_FORCE
- help
- Enables Android GKI symbol and export protection support.
- This modifies the behavior of the MODULE_SIG_FORCE as follows:
- - Allows Android GKI Modules signed using MODULE_SIG_ALL during build.
- - Allows other modules to load if they don't violate the access to
- Android GKI protected symbols and do not export the symbols already
- exported by the Android GKI modules. Loading will fail and return
- -EACCES (Permission denied) if symbol access conditions are not met.
- config MODULE_SIG_ALL
- bool "Automatically sign all modules"
- default y
- depends on MODULE_SIG || IMA_APPRAISE_MODSIG
- help
- Sign all modules during make modules_install. Without this option,
- modules must be signed manually, using the scripts/sign-file tool.
- comment "Do not forget to sign required modules with scripts/sign-file"
- depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
- choice
- prompt "Which hash algorithm should modules be signed with?"
- depends on MODULE_SIG || IMA_APPRAISE_MODSIG
- help
- This determines which sort of hashing algorithm will be used during
- signature generation. This algorithm _must_ be built into the kernel
- directly so that signature verification can take place. It is not
- possible to load a signed module containing the algorithm to check
- the signature on that module.
- config MODULE_SIG_SHA1
- bool "Sign modules with SHA-1"
- select CRYPTO_SHA1
- config MODULE_SIG_SHA224
- bool "Sign modules with SHA-224"
- select CRYPTO_SHA256
- config MODULE_SIG_SHA256
- bool "Sign modules with SHA-256"
- select CRYPTO_SHA256
- config MODULE_SIG_SHA384
- bool "Sign modules with SHA-384"
- select CRYPTO_SHA512
- config MODULE_SIG_SHA512
- bool "Sign modules with SHA-512"
- select CRYPTO_SHA512
- endchoice
- config MODULE_SIG_HASH
- string
- depends on MODULE_SIG || IMA_APPRAISE_MODSIG
- default "sha1" if MODULE_SIG_SHA1
- default "sha224" if MODULE_SIG_SHA224
- default "sha256" if MODULE_SIG_SHA256
- default "sha384" if MODULE_SIG_SHA384
- default "sha512" if MODULE_SIG_SHA512
- choice
- prompt "Module compression mode"
- help
- This option allows you to choose the algorithm which will be used to
- compress modules when 'make modules_install' is run. (or, you can
- choose to not compress modules at all.)
- External modules will also be compressed in the same way during the
- installation.
- For modules inside an initrd or initramfs, it's more efficient to
- compress the whole initrd or initramfs instead.
- This is fully compatible with signed modules.
- Please note that the tool used to load modules needs to support the
- corresponding algorithm. module-init-tools MAY support gzip, and kmod
- MAY support gzip, xz and zstd.
- Your build system needs to provide the appropriate compression tool
- to compress the modules.
- If in doubt, select 'None'.
- config MODULE_COMPRESS_NONE
- bool "None"
- help
- Do not compress modules. The installed modules are suffixed
- with .ko.
- config MODULE_COMPRESS_GZIP
- bool "GZIP"
- help
- Compress modules with GZIP. The installed modules are suffixed
- with .ko.gz.
- config MODULE_COMPRESS_XZ
- bool "XZ"
- help
- Compress modules with XZ. The installed modules are suffixed
- with .ko.xz.
- config MODULE_COMPRESS_ZSTD
- bool "ZSTD"
- help
- Compress modules with ZSTD. The installed modules are suffixed
- with .ko.zst.
- endchoice
- config MODULE_DECOMPRESS
- bool "Support in-kernel module decompression"
- depends on MODULE_COMPRESS_GZIP || MODULE_COMPRESS_XZ
- select ZLIB_INFLATE if MODULE_COMPRESS_GZIP
- select XZ_DEC if MODULE_COMPRESS_XZ
- help
- Support for decompressing kernel modules by the kernel itself
- instead of relying on userspace to perform this task. Useful when
- load pinning security policy is enabled.
- If unsure, say N.
- config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
- bool "Allow loading of modules with missing namespace imports"
- help
- Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in
- a namespace. A module that makes use of a symbol exported with such a
- namespace is required to import the namespace via MODULE_IMPORT_NS().
- There is no technical reason to enforce correct namespace imports,
- but it creates consistency between symbols defining namespaces and
- users importing namespaces they make use of. This option relaxes this
- requirement and lifts the enforcement when loading a module.
- If unsure, say N.
- config MODPROBE_PATH
- string "Path to modprobe binary"
- default "/sbin/modprobe"
- help
- When kernel code requests a module, it does so by calling
- the "modprobe" userspace utility. This option allows you to
- set the path where that binary is found. This can be changed
- at runtime via the sysctl file
- /proc/sys/kernel/modprobe. Setting this to the empty string
- removes the kernel's ability to request modules (but
- userspace can still load modules explicitly).
- config TRIM_UNUSED_KSYMS
- bool "Trim unused exported kernel symbols" if EXPERT
- depends on !COMPILE_TEST
- help
- The kernel and some modules make many symbols available for
- other modules to use via EXPORT_SYMBOL() and variants. Depending
- on the set of modules being selected in your kernel configuration,
- many of those exported symbols might never be used.
- This option allows for unused exported symbols to be dropped from
- the build. In turn, this provides the compiler more opportunities
- (especially when using LTO) for optimizing the code and reducing
- binary size. This might have some security advantages as well.
- If unsure, or if you need to build out-of-tree modules, say N.
- config UNUSED_KSYMS_WHITELIST
- string "Whitelist of symbols to keep in ksymtab"
- depends on TRIM_UNUSED_KSYMS
- help
- By default, all unused exported symbols will be un-exported from the
- build when TRIM_UNUSED_KSYMS is selected.
- UNUSED_KSYMS_WHITELIST allows to whitelist symbols that must be kept
- exported at all times, even in absence of in-tree users. The value to
- set here is the path to a text file containing the list of symbols,
- one per line. The path can be absolute, or relative to the kernel
- source tree.
- config MODULES_TREE_LOOKUP
- def_bool y
- depends on PERF_EVENTS || TRACING || CFI_CLANG
- endif # MODULES
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