[thirdparty/kernel/stable.git] / security / Kconfig

# SPDX-License-Identifier: GPL-2.0-only
#
# Security configuration
#

menu "Security options"

source "security/keys/Kconfig"

config SECURITY_DMESG_RESTRICT
	bool "Restrict unprivileged access to the kernel syslog"
	default n
	help
	  This enforces restrictions on unprivileged users reading the kernel
	  syslog via dmesg(8).

	  If this option is not selected, no restrictions will be enforced
	  unless the dmesg_restrict sysctl is explicitly set to (1).

	  If you are unsure how to answer this question, answer N.

config SECURITY
	bool "Enable different security models"
	depends on SYSFS
	depends on MULTIUSER
	help
	  This allows you to choose different security modules to be
	  configured into your kernel.

	  If this option is not selected, the default Linux security
	  model will be used.

	  If you are unsure how to answer this question, answer N.

config SECURITY_WRITABLE_HOOKS
	depends on SECURITY
	bool
	default n

config SECURITYFS
	bool "Enable the securityfs filesystem"
	help
	  This will build the securityfs filesystem.  It is currently used by
	  various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).

	  If you are unsure how to answer this question, answer N.

config SECURITY_NETWORK
	bool "Socket and Networking Security Hooks"
	depends on SECURITY
	help
	  This enables the socket and networking security hooks.
	  If enabled, a security module can use these hooks to
	  implement socket and networking access controls.
	  If you are unsure how to answer this question, answer N.

config PAGE_TABLE_ISOLATION
	bool "Remove the kernel mapping in user mode"
	default y
	depends on (X86_64 || X86_PAE) && !UML
	help
	  This feature reduces the number of hardware side channels by
	  ensuring that the majority of kernel addresses are not mapped
	  into userspace.

	  See Documentation/x86/pti.txt for more details.

config SECURITY_INFINIBAND
	bool "Infiniband Security Hooks"
	depends on SECURITY && INFINIBAND
	help
	  This enables the Infiniband security hooks.
	  If enabled, a security module can use these hooks to
	  implement Infiniband access controls.
	  If you are unsure how to answer this question, answer N.

config SECURITY_NETWORK_XFRM
	bool "XFRM (IPSec) Networking Security Hooks"
	depends on XFRM && SECURITY_NETWORK
	help
	  This enables the XFRM (IPSec) networking security hooks.
	  If enabled, a security module can use these hooks to
	  implement per-packet access controls based on labels
	  derived from IPSec policy.  Non-IPSec communications are
	  designated as unlabelled, and only sockets authorized
	  to communicate unlabelled data can send without using
	  IPSec.
	  If you are unsure how to answer this question, answer N.

config SECURITY_PATH
	bool "Security hooks for pathname based access control"
	depends on SECURITY
	help
	  This enables the security hooks for pathname based access control.
	  If enabled, a security module can use these hooks to
	  implement pathname based access controls.
	  If you are unsure how to answer this question, answer N.

config INTEL_TXT
	bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
	depends on HAVE_INTEL_TXT
	help
	  This option enables support for booting the kernel with the
	  Trusted Boot (tboot) module. This will utilize
	  Intel(R) Trusted Execution Technology to perform a measured launch
	  of the kernel. If the system does not support Intel(R) TXT, this
	  will have no effect.

	  Intel TXT will provide higher assurance of system configuration and
	  initial state as well as data reset protection.  This is used to
	  create a robust initial kernel measurement and verification, which
	  helps to ensure that kernel security mechanisms are functioning
	  correctly. This level of protection requires a root of trust outside
	  of the kernel itself.

	  Intel TXT also helps solve real end user concerns about having
	  confidence that their hardware is running the VMM or kernel that
	  it was configured with, especially since they may be responsible for
	  providing such assurances to VMs and services running on it.

	  See <http://www.intel.com/technology/security/> for more information
	  about Intel(R) TXT.
	  See <http://tboot.sourceforge.net> for more information about tboot.
	  See Documentation/intel_txt.txt for a description of how to enable
	  Intel TXT support in a kernel boot.

	  If you are unsure as to whether this is required, answer N.

config LSM_MMAP_MIN_ADDR
	int "Low address space for LSM to protect from user allocation"
	depends on SECURITY && SECURITY_SELINUX
	default 32768 if ARM || (ARM64 && COMPAT)
	default 65536
	help
	  This is the portion of low virtual memory which should be protected
	  from userspace allocation.  Keeping a user from writing to low pages
	  can help reduce the impact of kernel NULL pointer bugs.

	  For most ia64, ppc64 and x86 users with lots of address space
	  a value of 65536 is reasonable and should cause no problems.
	  On arm and other archs it should not be higher than 32768.
	  Programs which use vm86 functionality or have some need to map
	  this low address space will need the permission specific to the
	  systems running LSM.

config HAVE_HARDENED_USERCOPY_ALLOCATOR
	bool
	help
	  The heap allocator implements __check_heap_object() for
	  validating memory ranges against heap object sizes in
	  support of CONFIG_HARDENED_USERCOPY.

config HARDENED_USERCOPY
	bool "Harden memory copies between kernel and userspace"
	depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
	imply STRICT_DEVMEM
	help
	  This option checks for obviously wrong memory regions when
	  copying memory to/from the kernel (via copy_to_user() and
	  copy_from_user() functions) by rejecting memory ranges that
	  are larger than the specified heap object, span multiple
	  separately allocated pages, are not on the process stack,
	  or are part of the kernel text. This kills entire classes
	  of heap overflow exploits and similar kernel memory exposures.

config HARDENED_USERCOPY_FALLBACK
	bool "Allow usercopy whitelist violations to fallback to object size"
	depends on HARDENED_USERCOPY
	default y
	help
	  This is a temporary option that allows missing usercopy whitelists
	  to be discovered via a WARN() to the kernel log, instead of
	  rejecting the copy, falling back to non-whitelisted hardened
	  usercopy that checks the slab allocation size instead of the
	  whitelist size. This option will be removed once it seems like
	  all missing usercopy whitelists have been identified and fixed.
	  Booting with "slab_common.usercopy_fallback=Y/N" can change
	  this setting.

config HARDENED_USERCOPY_PAGESPAN
	bool "Refuse to copy allocations that span multiple pages"
	depends on HARDENED_USERCOPY
	depends on EXPERT
	help
	  When a multi-page allocation is done without __GFP_COMP,
	  hardened usercopy will reject attempts to copy it. There are,
	  however, several cases of this in the kernel that have not all
	  been removed. This config is intended to be used only while
	  trying to find such users.

config FORTIFY_SOURCE
	bool "Harden common str/mem functions against buffer overflows"
	depends on ARCH_HAS_FORTIFY_SOURCE
	help
	  Detect overflows of buffers in common string and memory functions
	  where the compiler can determine and validate the buffer sizes.

config STATIC_USERMODEHELPER
	bool "Force all usermode helper calls through a single binary"
	help
	  By default, the kernel can call many different userspace
	  binary programs through the "usermode helper" kernel
	  interface.  Some of these binaries are statically defined
	  either in the kernel code itself, or as a kernel configuration
	  option.  However, some of these are dynamically created at
	  runtime, or can be modified after the kernel has started up.
	  To provide an additional layer of security, route all of these
	  calls through a single executable that can not have its name
	  changed.

	  Note, it is up to this single binary to then call the relevant
	  "real" usermode helper binary, based on the first argument
	  passed to it.  If desired, this program can filter and pick
	  and choose what real programs are called.

	  If you wish for all usermode helper programs are to be
	  disabled, choose this option and then set
	  STATIC_USERMODEHELPER_PATH to an empty string.

config STATIC_USERMODEHELPER_PATH
	string "Path to the static usermode helper binary"
	depends on STATIC_USERMODEHELPER
	default "/sbin/usermode-helper"
	help
	  The binary called by the kernel when any usermode helper
	  program is wish to be run.  The "real" application's name will
	  be in the first argument passed to this program on the command
	  line.

	  If you wish for all usermode helper programs to be disabled,
	  specify an empty string here (i.e. "").

source "security/selinux/Kconfig"
source "security/smack/Kconfig"
source "security/tomoyo/Kconfig"
source "security/apparmor/Kconfig"
source "security/loadpin/Kconfig"
source "security/yama/Kconfig"
source "security/safesetid/Kconfig"

source "security/integrity/Kconfig"

choice
	prompt "First legacy 'major LSM' to be initialized"
	default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
	default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
	default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
	default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
	default DEFAULT_SECURITY_DAC

	help
	  This choice is there only for converting CONFIG_DEFAULT_SECURITY
	  in old kernel configs to CONFIG_LSM in new kernel configs. Don't
	  change this choice unless you are creating a fresh kernel config,
	  for this choice will be ignored after CONFIG_LSM has been set.

	  Selects the legacy "major security module" that will be
	  initialized first. Overridden by non-default CONFIG_LSM.

	config DEFAULT_SECURITY_SELINUX
		bool "SELinux" if SECURITY_SELINUX=y

	config DEFAULT_SECURITY_SMACK
		bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y

	config DEFAULT_SECURITY_TOMOYO
		bool "TOMOYO" if SECURITY_TOMOYO=y

	config DEFAULT_SECURITY_APPARMOR
		bool "AppArmor" if SECURITY_APPARMOR=y

	config DEFAULT_SECURITY_DAC
		bool "Unix Discretionary Access Controls"

endchoice

config LSM
	string "Ordered list of enabled LSMs"
	default "yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor" if DEFAULT_SECURITY_SMACK
	default "yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo" if DEFAULT_SECURITY_APPARMOR
	default "yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO
	default "yama,loadpin,safesetid,integrity" if DEFAULT_SECURITY_DAC
	default "yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"
	help
	  A comma-separated list of LSMs, in initialization order.
	  Any LSMs left off this list will be ignored. This can be
	  controlled at boot with the "lsm=" parameter.

	  If unsure, leave this as the default.

source "security/Kconfig.hardening"

endmenu
Commit	Line	Data
ec8f24b7	1	# SPDX-License-Identifier: GPL-2.0-only
1da177e4 LT	2	#
	3	# Security configuration
	4	#
	5
	6	menu "Security options"
	7
8636a1f9	8	source "security/keys/Kconfig"
1da177e4	9
eaf06b24 DR	10	config SECURITY_DMESG_RESTRICT
	11	bool "Restrict unprivileged access to the kernel syslog"
	12	default n
	13	help
	14	This enforces restrictions on unprivileged users reading the kernel
	15	syslog via dmesg(8).
	16
	17	If this option is not selected, no restrictions will be enforced
	18	unless the dmesg_restrict sysctl is explicitly set to (1).
	19
	20	If you are unsure how to answer this question, answer N.
	21
1da177e4 LT	22	config SECURITY
1da177e4 LT	23	bool "Enable different security models"
2c40579b	24	depends on SYSFS
2813893f	25	depends on MULTIUSER
1da177e4 LT	26	help
	27	This allows you to choose different security modules to be
	28	configured into your kernel.
	29
	30	If this option is not selected, the default Linux security
	31	model will be used.
	32
	33	If you are unsure how to answer this question, answer N.
	34
dd0859dc JM	35	config SECURITY_WRITABLE_HOOKS
	36	depends on SECURITY
	37	bool
	38	default n
	39
da31894e EP	40	config SECURITYFS
	41	bool "Enable the securityfs filesystem"
	42	help
	43	This will build the securityfs filesystem. It is currently used by
b102c11e	44	various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
da31894e EP	45
	46	If you are unsure how to answer this question, answer N.
	47
1da177e4 LT	48	config SECURITY_NETWORK
	49	bool "Socket and Networking Security Hooks"
	50	depends on SECURITY
	51	help
	52	This enables the socket and networking security hooks.
	53	If enabled, a security module can use these hooks to
	54	implement socket and networking access controls.
	55	If you are unsure how to answer this question, answer N.
df71837d	56
385ce0ea DH	57	config PAGE_TABLE_ISOLATION
385ce0ea DH	58	bool "Remove the kernel mapping in user mode"
87faa0d9	59	default y
61a6bd83	60	depends on (X86_64 \|\| X86_PAE) && !UML
385ce0ea DH	61	help
	62	This feature reduces the number of hardware side channels by
	63	ensuring that the majority of kernel addresses are not mapped
	64	into userspace.
	65
a237f762	66	See Documentation/x86/pti.txt for more details.
385ce0ea	67
d291f1a6 DJ	68	config SECURITY_INFINIBAND
	69	bool "Infiniband Security Hooks"
	70	depends on SECURITY && INFINIBAND
	71	help
	72	This enables the Infiniband security hooks.
	73	If enabled, a security module can use these hooks to
	74	implement Infiniband access controls.
	75	If you are unsure how to answer this question, answer N.
	76
df71837d TJ	77	config SECURITY_NETWORK_XFRM
	78	bool "XFRM (IPSec) Networking Security Hooks"
	79	depends on XFRM && SECURITY_NETWORK
	80	help
	81	This enables the XFRM (IPSec) networking security hooks.
	82	If enabled, a security module can use these hooks to
	83	implement per-packet access controls based on labels
	84	derived from IPSec policy. Non-IPSec communications are
	85	designated as unlabelled, and only sockets authorized
	86	to communicate unlabelled data can send without using
	87	IPSec.
	88	If you are unsure how to answer this question, answer N.
1da177e4	89
be6d3e56 KT	90	config SECURITY_PATH
	91	bool "Security hooks for pathname based access control"
	92	depends on SECURITY
	93	help
	94	This enables the security hooks for pathname based access control.
	95	If enabled, a security module can use these hooks to
	96	implement pathname based access controls.
	97	If you are unsure how to answer this question, answer N.
	98
31625340 JC	99	config INTEL_TXT
31625340 JC	100	bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
69575d38	101	depends on HAVE_INTEL_TXT
31625340 JC	102	help
	103	This option enables support for booting the kernel with the
	104	Trusted Boot (tboot) module. This will utilize
	105	Intel(R) Trusted Execution Technology to perform a measured launch
	106	of the kernel. If the system does not support Intel(R) TXT, this
	107	will have no effect.
	108
3c556e41	109	Intel TXT will provide higher assurance of system configuration and
31625340 JC	110	initial state as well as data reset protection. This is used to
	111	create a robust initial kernel measurement and verification, which
	112	helps to ensure that kernel security mechanisms are functioning
	113	correctly. This level of protection requires a root of trust outside
	114	of the kernel itself.
	115
	116	Intel TXT also helps solve real end user concerns about having
	117	confidence that their hardware is running the VMM or kernel that
3c556e41	118	it was configured with, especially since they may be responsible for
31625340 JC	119	providing such assurances to VMs and services running on it.
	120
	121	See <http://www.intel.com/technology/security/> for more information
	122	about Intel(R) TXT.
	123	See <http://tboot.sourceforge.net> for more information about tboot.
	124	See Documentation/intel_txt.txt for a description of how to enable
	125	Intel TXT support in a kernel boot.
	126
	127	If you are unsure as to whether this is required, answer N.
	128
788084ab	129	config LSM_MMAP_MIN_ADDR
024e6cb4	130	int "Low address space for LSM to protect from user allocation"
788084ab	131	depends on SECURITY && SECURITY_SELINUX
530b099d	132	default 32768 if ARM \|\| (ARM64 && COMPAT)
a58578e4	133	default 65536
788084ab EP	134	help
	135	This is the portion of low virtual memory which should be protected
	136	from userspace allocation. Keeping a user from writing to low pages
	137	can help reduce the impact of kernel NULL pointer bugs.
	138
	139	For most ia64, ppc64 and x86 users with lots of address space
	140	a value of 65536 is reasonable and should cause no problems.
	141	On arm and other archs it should not be higher than 32768.
	142	Programs which use vm86 functionality or have some need to map
	143	this low address space will need the permission specific to the
	144	systems running LSM.
	145
f5509cc1 KC	146	config HAVE_HARDENED_USERCOPY_ALLOCATOR
	147	bool
	148	help
	149	The heap allocator implements __check_heap_object() for
	150	validating memory ranges against heap object sizes in
	151	support of CONFIG_HARDENED_USERCOPY.
	152
f5509cc1 KC	153	config HARDENED_USERCOPY
f5509cc1 KC	154	bool "Harden memory copies between kernel and userspace"
6040e576	155	depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
22ec1a2a	156	imply STRICT_DEVMEM
f5509cc1 KC	157	help
	158	This option checks for obviously wrong memory regions when
	159	copying memory to/from the kernel (via copy_to_user() and
	160	copy_from_user() functions) by rejecting memory ranges that
	161	are larger than the specified heap object, span multiple
99c55fb1	162	separately allocated pages, are not on the process stack,
f5509cc1 KC	163	or are part of the kernel text. This kills entire classes
	164	of heap overflow exploits and similar kernel memory exposures.
	165
2d891fbc KC	166	config HARDENED_USERCOPY_FALLBACK
	167	bool "Allow usercopy whitelist violations to fallback to object size"
	168	depends on HARDENED_USERCOPY
	169	default y
	170	help
	171	This is a temporary option that allows missing usercopy whitelists
	172	to be discovered via a WARN() to the kernel log, instead of
	173	rejecting the copy, falling back to non-whitelisted hardened
	174	usercopy that checks the slab allocation size instead of the
	175	whitelist size. This option will be removed once it seems like
	176	all missing usercopy whitelists have been identified and fixed.
	177	Booting with "slab_common.usercopy_fallback=Y/N" can change
	178	this setting.
	179
8e1f74ea KC	180	config HARDENED_USERCOPY_PAGESPAN
	181	bool "Refuse to copy allocations that span multiple pages"
	182	depends on HARDENED_USERCOPY
80a77045	183	depends on EXPERT
8e1f74ea KC	184	help
	185	When a multi-page allocation is done without __GFP_COMP,
	186	hardened usercopy will reject attempts to copy it. There are,
	187	however, several cases of this in the kernel that have not all
	188	been removed. This config is intended to be used only while
	189	trying to find such users.
	190
6974f0c4 DM	191	config FORTIFY_SOURCE
	192	bool "Harden common str/mem functions against buffer overflows"
	193	depends on ARCH_HAS_FORTIFY_SOURCE
	194	help
	195	Detect overflows of buffers in common string and memory functions
	196	where the compiler can determine and validate the buffer sizes.
	197
64e90a8a GKH	198	config STATIC_USERMODEHELPER
	199	bool "Force all usermode helper calls through a single binary"
	200	help
	201	By default, the kernel can call many different userspace
	202	binary programs through the "usermode helper" kernel
	203	interface. Some of these binaries are statically defined
	204	either in the kernel code itself, or as a kernel configuration
	205	option. However, some of these are dynamically created at
	206	runtime, or can be modified after the kernel has started up.
	207	To provide an additional layer of security, route all of these
	208	calls through a single executable that can not have its name
	209	changed.
	210
	211	Note, it is up to this single binary to then call the relevant
	212	"real" usermode helper binary, based on the first argument
	213	passed to it. If desired, this program can filter and pick
	214	and choose what real programs are called.
	215
	216	If you wish for all usermode helper programs are to be
	217	disabled, choose this option and then set
	218	STATIC_USERMODEHELPER_PATH to an empty string.
	219
	220	config STATIC_USERMODEHELPER_PATH
	221	string "Path to the static usermode helper binary"
	222	depends on STATIC_USERMODEHELPER
	223	default "/sbin/usermode-helper"
	224	help
	225	The binary called by the kernel when any usermode helper
	226	program is wish to be run. The "real" application's name will
	227	be in the first argument passed to this program on the command
	228	line.
	229
	230	If you wish for all usermode helper programs to be disabled,
	231	specify an empty string here (i.e. "").
	232
8636a1f9 MY	233	source "security/selinux/Kconfig"
	234	source "security/smack/Kconfig"
	235	source "security/tomoyo/Kconfig"
	236	source "security/apparmor/Kconfig"
	237	source "security/loadpin/Kconfig"
	238	source "security/yama/Kconfig"
aeca4e2c	239	source "security/safesetid/Kconfig"
1da177e4	240
8636a1f9	241	source "security/integrity/Kconfig"
3323eec9	242
2623c4fb KC	243	choice
	244	prompt "First legacy 'major LSM' to be initialized"
	245	default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
	246	default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
	247	default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
	248	default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
	249	default DEFAULT_SECURITY_DAC
	250
	251	help
	252	This choice is there only for converting CONFIG_DEFAULT_SECURITY
	253	in old kernel configs to CONFIG_LSM in new kernel configs. Don't
	254	change this choice unless you are creating a fresh kernel config,
	255	for this choice will be ignored after CONFIG_LSM has been set.
	256
	257	Selects the legacy "major security module" that will be
	258	initialized first. Overridden by non-default CONFIG_LSM.
	259
	260	config DEFAULT_SECURITY_SELINUX
	261	bool "SELinux" if SECURITY_SELINUX=y
	262
	263	config DEFAULT_SECURITY_SMACK
	264	bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
	265
	266	config DEFAULT_SECURITY_TOMOYO
	267	bool "TOMOYO" if SECURITY_TOMOYO=y
	268
	269	config DEFAULT_SECURITY_APPARMOR
	270	bool "AppArmor" if SECURITY_APPARMOR=y
	271
	272	config DEFAULT_SECURITY_DAC
	273	bool "Unix Discretionary Access Controls"
	274
	275	endchoice
	276
13e735c0 KC	277	config LSM
13e735c0 KC	278	string "Ordered list of enabled LSMs"
2623c4fb KC	279	default "yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor" if DEFAULT_SECURITY_SMACK
	280	default "yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo" if DEFAULT_SECURITY_APPARMOR
	281	default "yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO
	282	default "yama,loadpin,safesetid,integrity" if DEFAULT_SECURITY_DAC
aeca4e2c	283	default "yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"
13e735c0 KC	284	help
13e735c0 KC	285	A comma-separated list of LSMs, in initialization order.
79f7865d KC	286	Any LSMs left off this list will be ignored. This can be
79f7865d KC	287	controlled at boot with the "lsm=" parameter.
13e735c0 KC	288
	289	If unsure, leave this as the default.
	290
9f671e58 KC	291	source "security/Kconfig.hardening"
9f671e58 KC	292
1da177e4 LT	293	endmenu
1da177e4 LT	294