Linux kernel mirror (for testing)
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linux
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 depends on SECURITY
273 default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,ipe,bpf" if DEFAULT_SECURITY_SMACK
274 default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,ipe,bpf" if DEFAULT_SECURITY_APPARMOR
275 default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,ipe,bpf" if DEFAULT_SECURITY_TOMOYO
276 default "landlock,lockdown,yama,loadpin,safesetid,ipe,bpf" if DEFAULT_SECURITY_DAC
277 default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,ipe,bpf"
278 help
279 A comma-separated list of LSMs, in initialization order.
280 Any LSMs left off this list, except for those with order
281 LSM_ORDER_FIRST and LSM_ORDER_LAST, which are always enabled
282 if selected in the kernel configuration, will be ignored.
283 This can be controlled at boot with the "lsm=" parameter.
284
285 If unsure, leave this as the default.
286
287source "security/Kconfig.hardening"
288
289endmenu
290