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![Kees Cook](/assets/img/avatar_default.png)
Commit70b62c2566
("LoadPin: Initialize as ordered LSM") removed CONFIG_DEFAULT_SECURITY_{SELINUX,SMACK,TOMOYO,APPARMOR,DAC} from security/Kconfig and changed CONFIG_LSM to provide a fixed ordering as a default value. That commit expected that existing users (upgrading from Linux 5.0 and earlier) will edit CONFIG_LSM value in accordance with their CONFIG_DEFAULT_SECURITY_* choice in their old kernel configs. But since users might forget to edit CONFIG_LSM value, this patch revives the choice (only for providing the default value for CONFIG_LSM) in order to make sure that CONFIG_LSM reflects CONFIG_DEFAULT_SECURITY_* from their old kernel configs. Note that since TOMOYO can be fully stacked against the other legacy major LSMs, when it is selected, it explicitly disables the other LSMs to avoid them also initializing since TOMOYO does not expect this currently. Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reported-by: Randy Dunlap <rdunlap@infradead.org> Fixes:70b62c2566
("LoadPin: Initialize as ordered LSM") Co-developed-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <james.morris@microsoft.com>
291 lines
10 KiB
Text
291 lines
10 KiB
Text
#
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# Security configuration
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#
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menu "Security options"
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source "security/keys/Kconfig"
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config SECURITY_DMESG_RESTRICT
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bool "Restrict unprivileged access to the kernel syslog"
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default n
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help
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This enforces restrictions on unprivileged users reading the kernel
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syslog via dmesg(8).
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If this option is not selected, no restrictions will be enforced
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unless the dmesg_restrict sysctl is explicitly set to (1).
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If you are unsure how to answer this question, answer N.
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config SECURITY
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bool "Enable different security models"
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depends on SYSFS
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depends on MULTIUSER
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help
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This allows you to choose different security modules to be
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configured into your kernel.
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If this option is not selected, the default Linux security
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model will be used.
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If you are unsure how to answer this question, answer N.
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config SECURITY_WRITABLE_HOOKS
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depends on SECURITY
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bool
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default n
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config SECURITYFS
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bool "Enable the securityfs filesystem"
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help
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This will build the securityfs filesystem. It is currently used by
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various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
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If you are unsure how to answer this question, answer N.
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config SECURITY_NETWORK
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bool "Socket and Networking Security Hooks"
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depends on SECURITY
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help
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This enables the socket and networking security hooks.
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If enabled, a security module can use these hooks to
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implement socket and networking access controls.
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If you are unsure how to answer this question, answer N.
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config PAGE_TABLE_ISOLATION
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bool "Remove the kernel mapping in user mode"
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default y
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depends on (X86_64 || X86_PAE) && !UML
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help
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This feature reduces the number of hardware side channels by
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ensuring that the majority of kernel addresses are not mapped
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into userspace.
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See Documentation/x86/pti.txt for more details.
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config SECURITY_INFINIBAND
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bool "Infiniband Security Hooks"
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depends on SECURITY && INFINIBAND
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help
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This enables the Infiniband security hooks.
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If enabled, a security module can use these hooks to
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implement Infiniband access controls.
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If you are unsure how to answer this question, answer N.
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config SECURITY_NETWORK_XFRM
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bool "XFRM (IPSec) Networking Security Hooks"
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depends on XFRM && SECURITY_NETWORK
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help
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This enables the XFRM (IPSec) networking security hooks.
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If enabled, a security module can use these hooks to
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implement per-packet access controls based on labels
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derived from IPSec policy. Non-IPSec communications are
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designated as unlabelled, and only sockets authorized
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to communicate unlabelled data can send without using
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IPSec.
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If you are unsure how to answer this question, answer N.
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config SECURITY_PATH
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bool "Security hooks for pathname based access control"
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depends on SECURITY
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help
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This enables the security hooks for pathname based access control.
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If enabled, a security module can use these hooks to
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implement pathname based access controls.
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If you are unsure how to answer this question, answer N.
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config INTEL_TXT
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bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
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depends on HAVE_INTEL_TXT
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help
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This option enables support for booting the kernel with the
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Trusted Boot (tboot) module. This will utilize
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Intel(R) Trusted Execution Technology to perform a measured launch
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of the kernel. If the system does not support Intel(R) TXT, this
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will have no effect.
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Intel TXT will provide higher assurance of system configuration and
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initial state as well as data reset protection. This is used to
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create a robust initial kernel measurement and verification, which
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helps to ensure that kernel security mechanisms are functioning
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correctly. This level of protection requires a root of trust outside
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of the kernel itself.
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Intel TXT also helps solve real end user concerns about having
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confidence that their hardware is running the VMM or kernel that
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it was configured with, especially since they may be responsible for
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providing such assurances to VMs and services running on it.
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See <http://www.intel.com/technology/security/> for more information
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about Intel(R) TXT.
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See <http://tboot.sourceforge.net> for more information about tboot.
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See Documentation/intel_txt.txt for a description of how to enable
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Intel TXT support in a kernel boot.
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If you are unsure as to whether this is required, answer N.
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config LSM_MMAP_MIN_ADDR
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int "Low address space for LSM to protect from user allocation"
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depends on SECURITY && SECURITY_SELINUX
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default 32768 if ARM || (ARM64 && COMPAT)
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default 65536
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help
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This is the portion of low virtual memory which should be protected
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from userspace allocation. Keeping a user from writing to low pages
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can help reduce the impact of kernel NULL pointer bugs.
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For most ia64, ppc64 and x86 users with lots of address space
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a value of 65536 is reasonable and should cause no problems.
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On arm and other archs it should not be higher than 32768.
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Programs which use vm86 functionality or have some need to map
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this low address space will need the permission specific to the
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systems running LSM.
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config HAVE_HARDENED_USERCOPY_ALLOCATOR
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bool
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help
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The heap allocator implements __check_heap_object() for
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validating memory ranges against heap object sizes in
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support of CONFIG_HARDENED_USERCOPY.
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config HARDENED_USERCOPY
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bool "Harden memory copies between kernel and userspace"
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depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
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imply STRICT_DEVMEM
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help
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This option checks for obviously wrong memory regions when
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copying memory to/from the kernel (via copy_to_user() and
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copy_from_user() functions) by rejecting memory ranges that
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are larger than the specified heap object, span multiple
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separately allocated pages, are not on the process stack,
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or are part of the kernel text. This kills entire classes
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of heap overflow exploits and similar kernel memory exposures.
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config HARDENED_USERCOPY_FALLBACK
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bool "Allow usercopy whitelist violations to fallback to object size"
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depends on HARDENED_USERCOPY
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default y
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help
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This is a temporary option that allows missing usercopy whitelists
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to be discovered via a WARN() to the kernel log, instead of
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rejecting the copy, falling back to non-whitelisted hardened
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usercopy that checks the slab allocation size instead of the
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whitelist size. This option will be removed once it seems like
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all missing usercopy whitelists have been identified and fixed.
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Booting with "slab_common.usercopy_fallback=Y/N" can change
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this setting.
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config HARDENED_USERCOPY_PAGESPAN
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bool "Refuse to copy allocations that span multiple pages"
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depends on HARDENED_USERCOPY
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depends on EXPERT
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help
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When a multi-page allocation is done without __GFP_COMP,
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hardened usercopy will reject attempts to copy it. There are,
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however, several cases of this in the kernel that have not all
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been removed. This config is intended to be used only while
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trying to find such users.
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config FORTIFY_SOURCE
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bool "Harden common str/mem functions against buffer overflows"
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depends on ARCH_HAS_FORTIFY_SOURCE
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help
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Detect overflows of buffers in common string and memory functions
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where the compiler can determine and validate the buffer sizes.
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config STATIC_USERMODEHELPER
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bool "Force all usermode helper calls through a single binary"
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help
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By default, the kernel can call many different userspace
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binary programs through the "usermode helper" kernel
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interface. Some of these binaries are statically defined
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either in the kernel code itself, or as a kernel configuration
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option. However, some of these are dynamically created at
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runtime, or can be modified after the kernel has started up.
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To provide an additional layer of security, route all of these
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calls through a single executable that can not have its name
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changed.
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Note, it is up to this single binary to then call the relevant
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"real" usermode helper binary, based on the first argument
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passed to it. If desired, this program can filter and pick
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and choose what real programs are called.
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If you wish for all usermode helper programs are to be
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disabled, choose this option and then set
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STATIC_USERMODEHELPER_PATH to an empty string.
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config STATIC_USERMODEHELPER_PATH
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string "Path to the static usermode helper binary"
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depends on STATIC_USERMODEHELPER
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default "/sbin/usermode-helper"
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help
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The binary called by the kernel when any usermode helper
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program is wish to be run. The "real" application's name will
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be in the first argument passed to this program on the command
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line.
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If you wish for all usermode helper programs to be disabled,
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specify an empty string here (i.e. "").
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source "security/selinux/Kconfig"
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source "security/smack/Kconfig"
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source "security/tomoyo/Kconfig"
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source "security/apparmor/Kconfig"
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source "security/loadpin/Kconfig"
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source "security/yama/Kconfig"
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source "security/safesetid/Kconfig"
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source "security/integrity/Kconfig"
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choice
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prompt "First legacy 'major LSM' to be initialized"
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default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
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default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
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default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
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default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
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default DEFAULT_SECURITY_DAC
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help
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This choice is there only for converting CONFIG_DEFAULT_SECURITY
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in old kernel configs to CONFIG_LSM in new kernel configs. Don't
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change this choice unless you are creating a fresh kernel config,
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for this choice will be ignored after CONFIG_LSM has been set.
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Selects the legacy "major security module" that will be
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initialized first. Overridden by non-default CONFIG_LSM.
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config DEFAULT_SECURITY_SELINUX
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bool "SELinux" if SECURITY_SELINUX=y
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config DEFAULT_SECURITY_SMACK
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bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
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config DEFAULT_SECURITY_TOMOYO
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bool "TOMOYO" if SECURITY_TOMOYO=y
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config DEFAULT_SECURITY_APPARMOR
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bool "AppArmor" if SECURITY_APPARMOR=y
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config DEFAULT_SECURITY_DAC
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bool "Unix Discretionary Access Controls"
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endchoice
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config LSM
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string "Ordered list of enabled LSMs"
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default "yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor" if DEFAULT_SECURITY_SMACK
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default "yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo" if DEFAULT_SECURITY_APPARMOR
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default "yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO
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default "yama,loadpin,safesetid,integrity" if DEFAULT_SECURITY_DAC
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default "yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"
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help
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A comma-separated list of LSMs, in initialization order.
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Any LSMs left off this list will be ignored. This can be
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controlled at boot with the "lsm=" parameter.
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If unsure, leave this as the default.
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endmenu
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