[linux-2.6-block.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.

choice
	prompt "Allow /proc/pid/mem access override"
	default PROC_MEM_ALWAYS_FORCE
	help
	  Traditionally /proc/pid/mem allows users to override memory
	  permissions for users like ptrace, assuming they have ptrace
	  capability.

	  This allows people to limit that - either never override, or
	  require actual active ptrace attachment.

	  Defaults to the traditional behavior (for now)

config PROC_MEM_ALWAYS_FORCE
	bool "Traditional /proc/pid/mem behavior"
	help
	  This allows /proc/pid/mem accesses to override memory mapping
	  permissions if you have ptrace access rights.

config PROC_MEM_FORCE_PTRACE
	bool "Require active ptrace() use for access override"
	help
	  This allows /proc/pid/mem accesses to override memory mapping
	  permissions for active ptracers like gdb.

config PROC_MEM_NO_FORCE
	bool "Never"
	help
	  Never override memory mapping permissions

endchoice

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 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/arch/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 HARDENED_USERCOPY
	bool "Harden memory copies between kernel and userspace"
	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 prevents entire classes
	  of heap overflow exploits and similar kernel memory exposures.

config FORTIFY_SOURCE
	bool "Harden common str/mem functions against buffer overflows"
	depends on ARCH_HAS_FORTIFY_SOURCE
	# https://github.com/llvm/llvm-project/issues/53645
	depends on !CC_IS_CLANG || !X86_32
	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/ipe/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,smack,selinux,tomoyo,apparmor,ipe,bpf" if DEFAULT_SECURITY_SMACK
	default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,ipe,bpf" if DEFAULT_SECURITY_APPARMOR
	default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,ipe,bpf" if DEFAULT_SECURITY_TOMOYO
	default "landlock,lockdown,yama,loadpin,safesetid,ipe,bpf" if DEFAULT_SECURITY_DAC
	default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,ipe,bpf"
	help
	  A comma-separated list of LSMs, in initialization order.
	  Any LSMs left off this list, except for those with order
	  LSM_ORDER_FIRST and LSM_ORDER_LAST, which are always enabled
	  if selected in the kernel configuration, 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
41e8149c AR	22	choice
	23	prompt "Allow /proc/pid/mem access override"
	24	default PROC_MEM_ALWAYS_FORCE
	25	help
	26	Traditionally /proc/pid/mem allows users to override memory
	27	permissions for users like ptrace, assuming they have ptrace
	28	capability.
	29
	30	This allows people to limit that - either never override, or
	31	require actual active ptrace attachment.
	32
	33	Defaults to the traditional behavior (for now)
	34
	35	config PROC_MEM_ALWAYS_FORCE
	36	bool "Traditional /proc/pid/mem behavior"
	37	help
	38	This allows /proc/pid/mem accesses to override memory mapping
	39	permissions if you have ptrace access rights.
	40
	41	config PROC_MEM_FORCE_PTRACE
	42	bool "Require active ptrace() use for access override"
	43	help
	44	This allows /proc/pid/mem accesses to override memory mapping
	45	permissions for active ptracers like gdb.
	46
	47	config PROC_MEM_NO_FORCE
	48	bool "Never"
	49	help
	50	Never override memory mapping permissions
	51
	52	endchoice
	53
1da177e4 LT	54	config SECURITY
1da177e4 LT	55	bool "Enable different security models"
2c40579b	56	depends on SYSFS
2813893f	57	depends on MULTIUSER
1da177e4 LT	58	help
	59	This allows you to choose different security modules to be
	60	configured into your kernel.
	61
	62	If this option is not selected, the default Linux security
	63	model will be used.
	64
	65	If you are unsure how to answer this question, answer N.
	66
da31894e EP	67	config SECURITYFS
	68	bool "Enable the securityfs filesystem"
	69	help
	70	This will build the securityfs filesystem. It is currently used by
b102c11e	71	various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
da31894e EP	72
	73	If you are unsure how to answer this question, answer N.
	74
1da177e4 LT	75	config SECURITY_NETWORK
	76	bool "Socket and Networking Security Hooks"
	77	depends on SECURITY
	78	help
	79	This enables the socket and networking security hooks.
	80	If enabled, a security module can use these hooks to
	81	implement socket and networking access controls.
	82	If you are unsure how to answer this question, answer N.
df71837d	83
d291f1a6 DJ	84	config SECURITY_INFINIBAND
	85	bool "Infiniband Security Hooks"
	86	depends on SECURITY && INFINIBAND
	87	help
	88	This enables the Infiniband security hooks.
	89	If enabled, a security module can use these hooks to
	90	implement Infiniband access controls.
	91	If you are unsure how to answer this question, answer N.
	92
df71837d TJ	93	config SECURITY_NETWORK_XFRM
	94	bool "XFRM (IPSec) Networking Security Hooks"
	95	depends on XFRM && SECURITY_NETWORK
	96	help
	97	This enables the XFRM (IPSec) networking security hooks.
	98	If enabled, a security module can use these hooks to
	99	implement per-packet access controls based on labels
	100	derived from IPSec policy. Non-IPSec communications are
	101	designated as unlabelled, and only sockets authorized
	102	to communicate unlabelled data can send without using
	103	IPSec.
	104	If you are unsure how to answer this question, answer N.
1da177e4	105
be6d3e56 KT	106	config SECURITY_PATH
	107	bool "Security hooks for pathname based access control"
	108	depends on SECURITY
	109	help
	110	This enables the security hooks for pathname based access control.
	111	If enabled, a security module can use these hooks to
	112	implement pathname based access controls.
	113	If you are unsure how to answer this question, answer N.
	114
31625340 JC	115	config INTEL_TXT
31625340 JC	116	bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
69575d38	117	depends on HAVE_INTEL_TXT
31625340 JC	118	help
	119	This option enables support for booting the kernel with the
	120	Trusted Boot (tboot) module. This will utilize
	121	Intel(R) Trusted Execution Technology to perform a measured launch
	122	of the kernel. If the system does not support Intel(R) TXT, this
	123	will have no effect.
	124
3c556e41	125	Intel TXT will provide higher assurance of system configuration and
31625340 JC	126	initial state as well as data reset protection. This is used to
	127	create a robust initial kernel measurement and verification, which
	128	helps to ensure that kernel security mechanisms are functioning
	129	correctly. This level of protection requires a root of trust outside
	130	of the kernel itself.
	131
	132	Intel TXT also helps solve real end user concerns about having
	133	confidence that their hardware is running the VMM or kernel that
3c556e41	134	it was configured with, especially since they may be responsible for
31625340 JC	135	providing such assurances to VMs and services running on it.
31625340 JC	136
c9fecf50	137	See <https://www.intel.com/technology/security/> for more information
31625340 JC	138	about Intel(R) TXT.
31625340 JC	139	See <http://tboot.sourceforge.net> for more information about tboot.
ff61f079	140	See Documentation/arch/x86/intel_txt.rst for a description of how to enable
31625340 JC	141	Intel TXT support in a kernel boot.
	142
	143	If you are unsure as to whether this is required, answer N.
	144
788084ab	145	config LSM_MMAP_MIN_ADDR
024e6cb4	146	int "Low address space for LSM to protect from user allocation"
788084ab	147	depends on SECURITY && SECURITY_SELINUX
530b099d	148	default 32768 if ARM \|\| (ARM64 && COMPAT)
a58578e4	149	default 65536
788084ab EP	150	help
	151	This is the portion of low virtual memory which should be protected
	152	from userspace allocation. Keeping a user from writing to low pages
	153	can help reduce the impact of kernel NULL pointer bugs.
	154
	155	For most ia64, ppc64 and x86 users with lots of address space
	156	a value of 65536 is reasonable and should cause no problems.
	157	On arm and other archs it should not be higher than 32768.
	158	Programs which use vm86 functionality or have some need to map
	159	this low address space will need the permission specific to the
	160	systems running LSM.
	161
f5509cc1 KC	162	config HARDENED_USERCOPY
f5509cc1 KC	163	bool "Harden memory copies between kernel and userspace"
22ec1a2a	164	imply STRICT_DEVMEM
f5509cc1 KC	165	help
	166	This option checks for obviously wrong memory regions when
	167	copying memory to/from the kernel (via copy_to_user() and
	168	copy_from_user() functions) by rejecting memory ranges that
	169	are larger than the specified heap object, span multiple
99c55fb1	170	separately allocated pages, are not on the process stack,
1109a5d9	171	or are part of the kernel text. This prevents entire classes
f5509cc1 KC	172	of heap overflow exploits and similar kernel memory exposures.
f5509cc1 KC	173
6974f0c4 DM	174	config FORTIFY_SOURCE
	175	bool "Harden common str/mem functions against buffer overflows"
	176	depends on ARCH_HAS_FORTIFY_SOURCE
281d0c96 KC	177	# https://github.com/llvm/llvm-project/issues/53645
281d0c96 KC	178	depends on !CC_IS_CLANG \|\| !X86_32
6974f0c4 DM	179	help
	180	Detect overflows of buffers in common string and memory functions
	181	where the compiler can determine and validate the buffer sizes.
	182
64e90a8a GKH	183	config STATIC_USERMODEHELPER
	184	bool "Force all usermode helper calls through a single binary"
	185	help
	186	By default, the kernel can call many different userspace
	187	binary programs through the "usermode helper" kernel
	188	interface. Some of these binaries are statically defined
	189	either in the kernel code itself, or as a kernel configuration
	190	option. However, some of these are dynamically created at
	191	runtime, or can be modified after the kernel has started up.
	192	To provide an additional layer of security, route all of these
	193	calls through a single executable that can not have its name
	194	changed.
	195
	196	Note, it is up to this single binary to then call the relevant
	197	"real" usermode helper binary, based on the first argument
	198	passed to it. If desired, this program can filter and pick
	199	and choose what real programs are called.
	200
	201	If you wish for all usermode helper programs are to be
	202	disabled, choose this option and then set
	203	STATIC_USERMODEHELPER_PATH to an empty string.
	204
	205	config STATIC_USERMODEHELPER_PATH
	206	string "Path to the static usermode helper binary"
	207	depends on STATIC_USERMODEHELPER
	208	default "/sbin/usermode-helper"
	209	help
	210	The binary called by the kernel when any usermode helper
	211	program is wish to be run. The "real" application's name will
	212	be in the first argument passed to this program on the command
	213	line.
	214
	215	If you wish for all usermode helper programs to be disabled,
	216	specify an empty string here (i.e. "").
	217
8636a1f9 MY	218	source "security/selinux/Kconfig"
	219	source "security/smack/Kconfig"
	220	source "security/tomoyo/Kconfig"
	221	source "security/apparmor/Kconfig"
	222	source "security/loadpin/Kconfig"
	223	source "security/yama/Kconfig"
aeca4e2c	224	source "security/safesetid/Kconfig"
000d388e	225	source "security/lockdown/Kconfig"
90945448	226	source "security/landlock/Kconfig"
03115077	227	source "security/ipe/Kconfig"
1da177e4	228
8636a1f9	229	source "security/integrity/Kconfig"
3323eec9	230
2623c4fb KC	231	choice
	232	prompt "First legacy 'major LSM' to be initialized"
	233	default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
	234	default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
	235	default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
	236	default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
	237	default DEFAULT_SECURITY_DAC
	238
	239	help
	240	This choice is there only for converting CONFIG_DEFAULT_SECURITY
	241	in old kernel configs to CONFIG_LSM in new kernel configs. Don't
	242	change this choice unless you are creating a fresh kernel config,
	243	for this choice will be ignored after CONFIG_LSM has been set.
	244
	245	Selects the legacy "major security module" that will be
	246	initialized first. Overridden by non-default CONFIG_LSM.
	247
	248	config DEFAULT_SECURITY_SELINUX
	249	bool "SELinux" if SECURITY_SELINUX=y
	250
	251	config DEFAULT_SECURITY_SMACK
	252	bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
	253
	254	config DEFAULT_SECURITY_TOMOYO
	255	bool "TOMOYO" if SECURITY_TOMOYO=y
	256
	257	config DEFAULT_SECURITY_APPARMOR
	258	bool "AppArmor" if SECURITY_APPARMOR=y
	259
	260	config DEFAULT_SECURITY_DAC
	261	bool "Unix Discretionary Access Controls"
	262
	263	endchoice
	264
13e735c0 KC	265	config LSM
13e735c0 KC	266	string "Ordered list of enabled LSMs"
03115077 DB	267	default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,ipe,bpf" if DEFAULT_SECURITY_SMACK
	268	default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,ipe,bpf" if DEFAULT_SECURITY_APPARMOR
	269	default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,ipe,bpf" if DEFAULT_SECURITY_TOMOYO
	270	default "landlock,lockdown,yama,loadpin,safesetid,ipe,bpf" if DEFAULT_SECURITY_DAC
	271	default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,ipe,bpf"
13e735c0 KC	272	help
13e735c0 KC	273	A comma-separated list of LSMs, in initialization order.
b9b8701b RS	274	Any LSMs left off this list, except for those with order
	275	LSM_ORDER_FIRST and LSM_ORDER_LAST, which are always enabled
	276	if selected in the kernel configuration, will be ignored.
	277	This can be controlled at boot with the "lsm=" parameter.
13e735c0 KC	278
	279	If unsure, leave this as the default.
	280
9f671e58 KC	281	source "security/Kconfig.hardening"
9f671e58 KC	282
1da177e4 LT	283	endmenu
1da177e4 LT	284