1# SPDX-License-Identifier: GPL-2.0-only
2#
3# Security configuration
4#
5
6menu "Security options"
7
8source "security/keys/Kconfig"
9
10config 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
22choice
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
35config 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
41config 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
47config PROC_MEM_NO_FORCE
48	bool "Never"
49	help
50	  Never override memory mapping permissions
51
52endchoice
53
54config MSEAL_SYSTEM_MAPPINGS
55	bool "mseal system mappings"
56	depends on 64BIT
57	depends on ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS
58	depends on !CHECKPOINT_RESTORE
59	help
60	  Apply mseal on system mappings.
61	  The system mappings includes vdso, vvar, vvar_vclock,
62	  vectors (arm compat-mode), sigpage (arm compat-mode), uprobes.
63
64	  A 64-bit kernel is required for the memory sealing feature.
65	  No specific hardware features from the CPU are needed.
66
67	  WARNING: This feature breaks programs which rely on relocating
68	  or unmapping system mappings. Known broken software at the time
69	  of writing includes CHECKPOINT_RESTORE, UML, gVisor, rr. Therefore
70	  this config can't be enabled universally.
71
72	  For complete descriptions of memory sealing, please see
73	  Documentation/userspace-api/mseal.rst
74
75config SECURITY
76	bool "Enable different security models"
77	depends on SYSFS
78	depends on MULTIUSER
79	help
80	  This allows you to choose different security modules to be
81	  configured into your kernel.
82
83	  If this option is not selected, the default Linux security
84	  model will be used.
85
86	  If you are unsure how to answer this question, answer N.
87
88config HAS_SECURITY_AUDIT
89	def_bool y
90	depends on AUDIT
91	depends on SECURITY
92
93config SECURITYFS
94	bool "Enable the securityfs filesystem"
95	help
96	  This will build the securityfs filesystem.  It is currently used by
97	  various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
98
99	  If you are unsure how to answer this question, answer N.
100
101config SECURITY_NETWORK
102	bool "Socket and Networking Security Hooks"
103	depends on SECURITY
104	help
105	  This enables the socket and networking security hooks.
106	  If enabled, a security module can use these hooks to
107	  implement socket and networking access controls.
108	  If you are unsure how to answer this question, answer N.
109
110config SECURITY_INFINIBAND
111	bool "Infiniband Security Hooks"
112	depends on SECURITY && INFINIBAND
113	help
114	  This enables the Infiniband security hooks.
115	  If enabled, a security module can use these hooks to
116	  implement Infiniband access controls.
117	  If you are unsure how to answer this question, answer N.
118
119config SECURITY_NETWORK_XFRM
120	bool "XFRM (IPSec) Networking Security Hooks"
121	depends on XFRM && SECURITY_NETWORK
122	help
123	  This enables the XFRM (IPSec) networking security hooks.
124	  If enabled, a security module can use these hooks to
125	  implement per-packet access controls based on labels
126	  derived from IPSec policy.  Non-IPSec communications are
127	  designated as unlabelled, and only sockets authorized
128	  to communicate unlabelled data can send without using
129	  IPSec.
130	  If you are unsure how to answer this question, answer N.
131
132config SECURITY_PATH
133	bool "Security hooks for pathname based access control"
134	depends on SECURITY
135	help
136	  This enables the security hooks for pathname based access control.
137	  If enabled, a security module can use these hooks to
138	  implement pathname based access controls.
139	  If you are unsure how to answer this question, answer N.
140
141config INTEL_TXT
142	bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
143	depends on HAVE_INTEL_TXT
144	help
145	  This option enables support for booting the kernel with the
146	  Trusted Boot (tboot) module. This will utilize
147	  Intel(R) Trusted Execution Technology to perform a measured launch
148	  of the kernel. If the system does not support Intel(R) TXT, this
149	  will have no effect.
150
151	  Intel TXT will provide higher assurance of system configuration and
152	  initial state as well as data reset protection.  This is used to
153	  create a robust initial kernel measurement and verification, which
154	  helps to ensure that kernel security mechanisms are functioning
155	  correctly. This level of protection requires a root of trust outside
156	  of the kernel itself.
157
158	  Intel TXT also helps solve real end user concerns about having
159	  confidence that their hardware is running the VMM or kernel that
160	  it was configured with, especially since they may be responsible for
161	  providing such assurances to VMs and services running on it.
162
163	  See <https://www.intel.com/technology/security/> for more information
164	  about Intel(R) TXT.
165	  See <http://tboot.sourceforge.net> for more information about tboot.
166	  See Documentation/arch/x86/intel_txt.rst for a description of how to enable
167	  Intel TXT support in a kernel boot.
168
169	  If you are unsure as to whether this is required, answer N.
170
171config LSM_MMAP_MIN_ADDR
172	int "Low address space for LSM to protect from user allocation"
173	depends on SECURITY && SECURITY_SELINUX
174	default 32768 if ARM || (ARM64 && COMPAT)
175	default 65536
176	help
177	  This is the portion of low virtual memory which should be protected
178	  from userspace allocation.  Keeping a user from writing to low pages
179	  can help reduce the impact of kernel NULL pointer bugs.
180
181	  For most ia64, ppc64 and x86 users with lots of address space
182	  a value of 65536 is reasonable and should cause no problems.
183	  On arm and other archs it should not be higher than 32768.
184	  Programs which use vm86 functionality or have some need to map
185	  this low address space will need the permission specific to the
186	  systems running LSM.
187
188config STATIC_USERMODEHELPER
189	bool "Force all usermode helper calls through a single binary"
190	help
191	  By default, the kernel can call many different userspace
192	  binary programs through the "usermode helper" kernel
193	  interface.  Some of these binaries are statically defined
194	  either in the kernel code itself, or as a kernel configuration
195	  option.  However, some of these are dynamically created at
196	  runtime, or can be modified after the kernel has started up.
197	  To provide an additional layer of security, route all of these
198	  calls through a single executable that can not have its name
199	  changed.
200
201	  Note, it is up to this single binary to then call the relevant
202	  "real" usermode helper binary, based on the first argument
203	  passed to it.  If desired, this program can filter and pick
204	  and choose what real programs are called.
205
206	  If you wish for all usermode helper programs are to be
207	  disabled, choose this option and then set
208	  STATIC_USERMODEHELPER_PATH to an empty string.
209
210config STATIC_USERMODEHELPER_PATH
211	string "Path to the static usermode helper binary"
212	depends on STATIC_USERMODEHELPER
213	default "/sbin/usermode-helper"
214	help
215	  The binary called by the kernel when any usermode helper
216	  program is wish to be run.  The "real" application's name will
217	  be in the first argument passed to this program on the command
218	  line.
219
220	  If you wish for all usermode helper programs to be disabled,
221	  specify an empty string here (i.e. "").
222
223source "security/selinux/Kconfig"
224source "security/smack/Kconfig"
225source "security/tomoyo/Kconfig"
226source "security/apparmor/Kconfig"
227source "security/loadpin/Kconfig"
228source "security/yama/Kconfig"
229source "security/safesetid/Kconfig"
230source "security/lockdown/Kconfig"
231source "security/landlock/Kconfig"
232source "security/ipe/Kconfig"
233
234source "security/integrity/Kconfig"
235
236choice
237	prompt "First legacy 'major LSM' to be initialized"
238	default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
239	default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
240	default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
241	default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
242	default DEFAULT_SECURITY_DAC
243
244	help
245	  This choice is there only for converting CONFIG_DEFAULT_SECURITY
246	  in old kernel configs to CONFIG_LSM in new kernel configs. Don't
247	  change this choice unless you are creating a fresh kernel config,
248	  for this choice will be ignored after CONFIG_LSM has been set.
249
250	  Selects the legacy "major security module" that will be
251	  initialized first. Overridden by non-default CONFIG_LSM.
252
253	config DEFAULT_SECURITY_SELINUX
254		bool "SELinux" if SECURITY_SELINUX=y
255
256	config DEFAULT_SECURITY_SMACK
257		bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
258
259	config DEFAULT_SECURITY_TOMOYO
260		bool "TOMOYO" if SECURITY_TOMOYO=y
261
262	config DEFAULT_SECURITY_APPARMOR
263		bool "AppArmor" if SECURITY_APPARMOR=y
264
265	config DEFAULT_SECURITY_DAC
266		bool "Unix Discretionary Access Controls"
267
268endchoice
269
270config LSM
271	string "Ordered list of enabled LSMs"
272	default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,ipe,bpf" if DEFAULT_SECURITY_SMACK
273	default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,ipe,bpf" if DEFAULT_SECURITY_APPARMOR
274	default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,ipe,bpf" if DEFAULT_SECURITY_TOMOYO
275	default "landlock,lockdown,yama,loadpin,safesetid,ipe,bpf" if DEFAULT_SECURITY_DAC
276	default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,ipe,bpf"
277	help
278	  A comma-separated list of LSMs, in initialization order.
279	  Any LSMs left off this list, except for those with order
280	  LSM_ORDER_FIRST and LSM_ORDER_LAST, which are always enabled
281	  if selected in the kernel configuration, will be ignored.
282	  This can be controlled at boot with the "lsm=" parameter.
283
284	  If unsure, leave this as the default.
285
286source "security/Kconfig.hardening"
287
288endmenu
289
290