In init/Kconfig, the part dedicated to modules is quite large. Move it into a dedicated Kconfig in kernel/module/ MODULES_TREE_LOOKUP was outside of the 'if MODULES', but as it is only used when MODULES are set, move it in with everything else to avoid confusion. MODULE_SIG_FORMAT is left in init/Kconfig because this configuration item is not used in kernel/modules/ but in kernel/ and can be selected independently from CONFIG_MODULES. It is for instance selected from security/integrity/ima/Kconfig. Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> --- init/Kconfig | 293 +----------------------------------------- kernel/module/Kconfig | 293 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 294 insertions(+), 292 deletions(-) create mode 100644 kernel/module/Kconfig diff --git a/init/Kconfig b/init/Kconfig index c7900e8975f1..f6109052d8d0 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1922,298 +1922,7 @@ config MODULE_SIG_FORMAT def_bool n select SYSTEM_DATA_VERIFICATION -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_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_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. - -endif # MODULES - -config MODULES_TREE_LOOKUP - def_bool y - depends on PERF_EVENTS || TRACING || CFI_CLANG +source "kernel/module/Kconfig" config INIT_ALL_POSSIBLE bool diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig new file mode 100644 index 000000000000..26ea5d04f56c --- /dev/null +++ b/kernel/module/Kconfig @@ -0,0 +1,293 @@ +# 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_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_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 -- 2.36.1
