[mirror_ubuntu-jammy-kernel.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_PERF_EVENTS_RESTRICT
	bool "Restrict unprivileged use of performance events"
	depends on PERF_EVENTS
	help
	  If you say Y here, the kernel.perf_event_paranoid sysctl
	  will be set to 3 by default, and no unprivileged use of the
	  perf_event_open syscall will be permitted unless it is
	  changed.

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 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 <https://www.intel.com/technology/security/> for more information
	  about Intel(R) TXT.
	  See <http://tboot.sourceforge.net> for more information about tboot.
	  See Documentation/x86/intel_txt.rst 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
	# https://bugs.llvm.org/show_bug.cgi?id=50322
	# https://bugs.llvm.org/show_bug.cgi?id=41459
	depends on !CC_IS_CLANG
	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/lockdown/Kconfig"
source "security/landlock/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 "landlock,lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
	default "landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
	default "landlock,lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
	default "landlock,lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC
	default "landlock,lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf"
	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
ba01d1d2 BH	22	config SECURITY_PERF_EVENTS_RESTRICT
	23	bool "Restrict unprivileged use of performance events"
	24	depends on PERF_EVENTS
	25	help
	26	If you say Y here, the kernel.perf_event_paranoid sysctl
	27	will be set to 3 by default, and no unprivileged use of the
	28	perf_event_open syscall will be permitted unless it is
	29	changed.
	30
1da177e4 LT	31	config SECURITY
1da177e4 LT	32	bool "Enable different security models"
2c40579b	33	depends on SYSFS
2813893f	34	depends on MULTIUSER
1da177e4 LT	35	help
	36	This allows you to choose different security modules to be
	37	configured into your kernel.
	38
	39	If this option is not selected, the default Linux security
	40	model will be used.
	41
	42	If you are unsure how to answer this question, answer N.
	43
dd0859dc JM	44	config SECURITY_WRITABLE_HOOKS
	45	depends on SECURITY
	46	bool
	47	default n
	48
da31894e EP	49	config SECURITYFS
	50	bool "Enable the securityfs filesystem"
	51	help
	52	This will build the securityfs filesystem. It is currently used by
b102c11e	53	various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
da31894e EP	54
	55	If you are unsure how to answer this question, answer N.
	56
1da177e4 LT	57	config SECURITY_NETWORK
	58	bool "Socket and Networking Security Hooks"
	59	depends on SECURITY
	60	help
	61	This enables the socket and networking security hooks.
	62	If enabled, a security module can use these hooks to
	63	implement socket and networking access controls.
	64	If you are unsure how to answer this question, answer N.
df71837d	65
d291f1a6 DJ	66	config SECURITY_INFINIBAND
	67	bool "Infiniband Security Hooks"
	68	depends on SECURITY && INFINIBAND
	69	help
	70	This enables the Infiniband security hooks.
	71	If enabled, a security module can use these hooks to
	72	implement Infiniband access controls.
	73	If you are unsure how to answer this question, answer N.
	74
df71837d TJ	75	config SECURITY_NETWORK_XFRM
	76	bool "XFRM (IPSec) Networking Security Hooks"
	77	depends on XFRM && SECURITY_NETWORK
	78	help
	79	This enables the XFRM (IPSec) networking security hooks.
	80	If enabled, a security module can use these hooks to
	81	implement per-packet access controls based on labels
	82	derived from IPSec policy. Non-IPSec communications are
	83	designated as unlabelled, and only sockets authorized
	84	to communicate unlabelled data can send without using
	85	IPSec.
	86	If you are unsure how to answer this question, answer N.
1da177e4	87
be6d3e56 KT	88	config SECURITY_PATH
	89	bool "Security hooks for pathname based access control"
	90	depends on SECURITY
	91	help
	92	This enables the security hooks for pathname based access control.
	93	If enabled, a security module can use these hooks to
	94	implement pathname based access controls.
	95	If you are unsure how to answer this question, answer N.
	96
31625340 JC	97	config INTEL_TXT
31625340 JC	98	bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
69575d38	99	depends on HAVE_INTEL_TXT
31625340 JC	100	help
	101	This option enables support for booting the kernel with the
	102	Trusted Boot (tboot) module. This will utilize
	103	Intel(R) Trusted Execution Technology to perform a measured launch
	104	of the kernel. If the system does not support Intel(R) TXT, this
	105	will have no effect.
	106
3c556e41	107	Intel TXT will provide higher assurance of system configuration and
31625340 JC	108	initial state as well as data reset protection. This is used to
	109	create a robust initial kernel measurement and verification, which
	110	helps to ensure that kernel security mechanisms are functioning
	111	correctly. This level of protection requires a root of trust outside
	112	of the kernel itself.
	113
	114	Intel TXT also helps solve real end user concerns about having
	115	confidence that their hardware is running the VMM or kernel that
3c556e41	116	it was configured with, especially since they may be responsible for
31625340 JC	117	providing such assurances to VMs and services running on it.
31625340 JC	118
c9fecf50	119	See <https://www.intel.com/technology/security/> for more information
31625340 JC	120	about Intel(R) TXT.
31625340 JC	121	See <http://tboot.sourceforge.net> for more information about tboot.
e8d776f2	122	See Documentation/x86/intel_txt.rst for a description of how to enable
31625340 JC	123	Intel TXT support in a kernel boot.
	124
	125	If you are unsure as to whether this is required, answer N.
	126
788084ab	127	config LSM_MMAP_MIN_ADDR
024e6cb4	128	int "Low address space for LSM to protect from user allocation"
788084ab	129	depends on SECURITY && SECURITY_SELINUX
530b099d	130	default 32768 if ARM \|\| (ARM64 && COMPAT)
a58578e4	131	default 65536
788084ab EP	132	help
	133	This is the portion of low virtual memory which should be protected
	134	from userspace allocation. Keeping a user from writing to low pages
	135	can help reduce the impact of kernel NULL pointer bugs.
	136
	137	For most ia64, ppc64 and x86 users with lots of address space
	138	a value of 65536 is reasonable and should cause no problems.
	139	On arm and other archs it should not be higher than 32768.
	140	Programs which use vm86 functionality or have some need to map
	141	this low address space will need the permission specific to the
	142	systems running LSM.
	143
f5509cc1 KC	144	config HAVE_HARDENED_USERCOPY_ALLOCATOR
	145	bool
	146	help
	147	The heap allocator implements __check_heap_object() for
	148	validating memory ranges against heap object sizes in
	149	support of CONFIG_HARDENED_USERCOPY.
	150
f5509cc1 KC	151	config HARDENED_USERCOPY
f5509cc1 KC	152	bool "Harden memory copies between kernel and userspace"
6040e576	153	depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
22ec1a2a	154	imply STRICT_DEVMEM
f5509cc1 KC	155	help
	156	This option checks for obviously wrong memory regions when
	157	copying memory to/from the kernel (via copy_to_user() and
	158	copy_from_user() functions) by rejecting memory ranges that
	159	are larger than the specified heap object, span multiple
99c55fb1	160	separately allocated pages, are not on the process stack,
f5509cc1 KC	161	or are part of the kernel text. This kills entire classes
	162	of heap overflow exploits and similar kernel memory exposures.
	163
2d891fbc KC	164	config HARDENED_USERCOPY_FALLBACK
	165	bool "Allow usercopy whitelist violations to fallback to object size"
	166	depends on HARDENED_USERCOPY
	167	default y
	168	help
	169	This is a temporary option that allows missing usercopy whitelists
	170	to be discovered via a WARN() to the kernel log, instead of
	171	rejecting the copy, falling back to non-whitelisted hardened
	172	usercopy that checks the slab allocation size instead of the
	173	whitelist size. This option will be removed once it seems like
	174	all missing usercopy whitelists have been identified and fixed.
	175	Booting with "slab_common.usercopy_fallback=Y/N" can change
	176	this setting.
	177
8e1f74ea KC	178	config HARDENED_USERCOPY_PAGESPAN
	179	bool "Refuse to copy allocations that span multiple pages"
	180	depends on HARDENED_USERCOPY
80a77045	181	depends on EXPERT
8e1f74ea KC	182	help
	183	When a multi-page allocation is done without __GFP_COMP,
	184	hardened usercopy will reject attempts to copy it. There are,
	185	however, several cases of this in the kernel that have not all
	186	been removed. This config is intended to be used only while
	187	trying to find such users.
	188
6974f0c4 DM	189	config FORTIFY_SOURCE
	190	bool "Harden common str/mem functions against buffer overflows"
	191	depends on ARCH_HAS_FORTIFY_SOURCE
379d24f0 KC	192	# https://bugs.llvm.org/show_bug.cgi?id=50322
	193	# https://bugs.llvm.org/show_bug.cgi?id=41459
	194	depends on !CC_IS_CLANG
6974f0c4 DM	195	help
	196	Detect overflows of buffers in common string and memory functions
	197	where the compiler can determine and validate the buffer sizes.
	198
64e90a8a GKH	199	config STATIC_USERMODEHELPER
	200	bool "Force all usermode helper calls through a single binary"
	201	help
	202	By default, the kernel can call many different userspace
	203	binary programs through the "usermode helper" kernel
	204	interface. Some of these binaries are statically defined
	205	either in the kernel code itself, or as a kernel configuration
	206	option. However, some of these are dynamically created at
	207	runtime, or can be modified after the kernel has started up.
	208	To provide an additional layer of security, route all of these
	209	calls through a single executable that can not have its name
	210	changed.
	211
	212	Note, it is up to this single binary to then call the relevant
	213	"real" usermode helper binary, based on the first argument
	214	passed to it. If desired, this program can filter and pick
	215	and choose what real programs are called.
	216
	217	If you wish for all usermode helper programs are to be
	218	disabled, choose this option and then set
	219	STATIC_USERMODEHELPER_PATH to an empty string.
	220
	221	config STATIC_USERMODEHELPER_PATH
	222	string "Path to the static usermode helper binary"
	223	depends on STATIC_USERMODEHELPER
	224	default "/sbin/usermode-helper"
	225	help
	226	The binary called by the kernel when any usermode helper
	227	program is wish to be run. The "real" application's name will
	228	be in the first argument passed to this program on the command
	229	line.
	230
	231	If you wish for all usermode helper programs to be disabled,
	232	specify an empty string here (i.e. "").
	233
8636a1f9 MY	234	source "security/selinux/Kconfig"
	235	source "security/smack/Kconfig"
	236	source "security/tomoyo/Kconfig"
	237	source "security/apparmor/Kconfig"
	238	source "security/loadpin/Kconfig"
	239	source "security/yama/Kconfig"
aeca4e2c	240	source "security/safesetid/Kconfig"
000d388e	241	source "security/lockdown/Kconfig"
90945448	242	source "security/landlock/Kconfig"
1da177e4	243
8636a1f9	244	source "security/integrity/Kconfig"
3323eec9	245
2623c4fb KC	246	choice
	247	prompt "First legacy 'major LSM' to be initialized"
	248	default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
	249	default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
	250	default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
	251	default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
	252	default DEFAULT_SECURITY_DAC
	253
	254	help
	255	This choice is there only for converting CONFIG_DEFAULT_SECURITY
	256	in old kernel configs to CONFIG_LSM in new kernel configs. Don't
	257	change this choice unless you are creating a fresh kernel config,
	258	for this choice will be ignored after CONFIG_LSM has been set.
	259
	260	Selects the legacy "major security module" that will be
	261	initialized first. Overridden by non-default CONFIG_LSM.
	262
	263	config DEFAULT_SECURITY_SELINUX
	264	bool "SELinux" if SECURITY_SELINUX=y
	265
	266	config DEFAULT_SECURITY_SMACK
	267	bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
	268
	269	config DEFAULT_SECURITY_TOMOYO
	270	bool "TOMOYO" if SECURITY_TOMOYO=y
	271
	272	config DEFAULT_SECURITY_APPARMOR
	273	bool "AppArmor" if SECURITY_APPARMOR=y
	274
	275	config DEFAULT_SECURITY_DAC
	276	bool "Unix Discretionary Access Controls"
	277
	278	endchoice
	279
13e735c0 KC	280	config LSM
13e735c0 KC	281	string "Ordered list of enabled LSMs"
385975dc MS	282	default "landlock,lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
	283	default "landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
	284	default "landlock,lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
	285	default "landlock,lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC
	286	default "landlock,lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf"
13e735c0 KC	287	help
13e735c0 KC	288	A comma-separated list of LSMs, in initialization order.
79f7865d KC	289	Any LSMs left off this list will be ignored. This can be
79f7865d KC	290	controlled at boot with the "lsm=" parameter.
13e735c0 KC	291
	292	If unsure, leave this as the default.
	293
9f671e58 KC	294	source "security/Kconfig.hardening"
9f671e58 KC	295
1da177e4 LT	296	endmenu
1da177e4 LT	297