1 # SPDX-License-Identifier: GPL-2.0-only
3 # Security configuration
6 menu "Security options"
8 source "security/keys/Kconfig"
10 config SECURITY_DMESG_RESTRICT
11 bool "Restrict unprivileged access to the kernel syslog"
14 This enforces restrictions on unprivileged users reading the kernel
17 If this option is not selected, no restrictions will be enforced
18 unless the dmesg_restrict sysctl is explicitly set to (1).
20 If you are unsure how to answer this question, answer N.
23 bool "Enable different security models"
27 This allows you to choose different security modules to be
28 configured into your kernel.
30 If this option is not selected, the default Linux security
33 If you are unsure how to answer this question, answer N.
35 config SECURITY_WRITABLE_HOOKS
41 bool "Enable the securityfs filesystem"
43 This will build the securityfs filesystem. It is currently used by
44 various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
46 If you are unsure how to answer this question, answer N.
48 config SECURITY_NETWORK
49 bool "Socket and Networking Security Hooks"
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.
57 config PAGE_TABLE_ISOLATION
58 bool "Remove the kernel mapping in user mode"
60 depends on (X86_64 || X86_PAE) && !UML
62 This feature reduces the number of hardware side channels by
63 ensuring that the majority of kernel addresses are not mapped
66 See Documentation/x86/pti.rst for more details.
68 config SECURITY_INFINIBAND
69 bool "Infiniband Security Hooks"
70 depends on SECURITY && INFINIBAND
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.
77 config SECURITY_NETWORK_XFRM
78 bool "XFRM (IPSec) Networking Security Hooks"
79 depends on XFRM && SECURITY_NETWORK
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
88 If you are unsure how to answer this question, answer N.
91 bool "Security hooks for pathname based access control"
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.
100 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
101 depends on HAVE_INTEL_TXT
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
109 Intel TXT will provide higher assurance of system configuration and
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.
116 Intel TXT also helps solve real end user concerns about having
117 confidence that their hardware is running the VMM or kernel that
118 it was configured with, especially since they may be responsible for
119 providing such assurances to VMs and services running on it.
121 See <http://www.intel.com/technology/security/> for more information
123 See <http://tboot.sourceforge.net> for more information about tboot.
124 See Documentation/x86/intel_txt.rst for a description of how to enable
125 Intel TXT support in a kernel boot.
127 If you are unsure as to whether this is required, answer N.
129 config LSM_MMAP_MIN_ADDR
130 int "Low address space for LSM to protect from user allocation"
131 depends on SECURITY && SECURITY_SELINUX
132 default 32768 if ARM || (ARM64 && COMPAT)
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.
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
146 config HAVE_HARDENED_USERCOPY_ALLOCATOR
149 The heap allocator implements __check_heap_object() for
150 validating memory ranges against heap object sizes in
151 support of CONFIG_HARDENED_USERCOPY.
153 config HARDENED_USERCOPY
154 bool "Harden memory copies between kernel and userspace"
155 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
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
162 separately allocated pages, are not on the process stack,
163 or are part of the kernel text. This kills entire classes
164 of heap overflow exploits and similar kernel memory exposures.
166 config HARDENED_USERCOPY_FALLBACK
167 bool "Allow usercopy whitelist violations to fallback to object size"
168 depends on HARDENED_USERCOPY
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
180 config HARDENED_USERCOPY_PAGESPAN
181 bool "Refuse to copy allocations that span multiple pages"
182 depends on HARDENED_USERCOPY
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.
191 config FORTIFY_SOURCE
192 bool "Harden common str/mem functions against buffer overflows"
193 depends on ARCH_HAS_FORTIFY_SOURCE
194 # https://bugs.llvm.org/show_bug.cgi?id=50322
195 # https://bugs.llvm.org/show_bug.cgi?id=41459
196 depends on !CC_IS_CLANG
198 Detect overflows of buffers in common string and memory functions
199 where the compiler can determine and validate the buffer sizes.
201 config STATIC_USERMODEHELPER
202 bool "Force all usermode helper calls through a single binary"
204 By default, the kernel can call many different userspace
205 binary programs through the "usermode helper" kernel
206 interface. Some of these binaries are statically defined
207 either in the kernel code itself, or as a kernel configuration
208 option. However, some of these are dynamically created at
209 runtime, or can be modified after the kernel has started up.
210 To provide an additional layer of security, route all of these
211 calls through a single executable that can not have its name
214 Note, it is up to this single binary to then call the relevant
215 "real" usermode helper binary, based on the first argument
216 passed to it. If desired, this program can filter and pick
217 and choose what real programs are called.
219 If you wish for all usermode helper programs are to be
220 disabled, choose this option and then set
221 STATIC_USERMODEHELPER_PATH to an empty string.
223 config STATIC_USERMODEHELPER_PATH
224 string "Path to the static usermode helper binary"
225 depends on STATIC_USERMODEHELPER
226 default "/sbin/usermode-helper"
228 The binary called by the kernel when any usermode helper
229 program is wish to be run. The "real" application's name will
230 be in the first argument passed to this program on the command
233 If you wish for all usermode helper programs to be disabled,
234 specify an empty string here (i.e. "").
236 source "security/selinux/Kconfig"
237 source "security/smack/Kconfig"
238 source "security/tomoyo/Kconfig"
239 source "security/apparmor/Kconfig"
240 source "security/loadpin/Kconfig"
241 source "security/yama/Kconfig"
242 source "security/safesetid/Kconfig"
243 source "security/lockdown/Kconfig"
245 source "security/integrity/Kconfig"
248 prompt "First legacy 'major LSM' to be initialized"
249 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
250 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
251 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
252 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
253 default DEFAULT_SECURITY_DAC
256 This choice is there only for converting CONFIG_DEFAULT_SECURITY
257 in old kernel configs to CONFIG_LSM in new kernel configs. Don't
258 change this choice unless you are creating a fresh kernel config,
259 for this choice will be ignored after CONFIG_LSM has been set.
261 Selects the legacy "major security module" that will be
262 initialized first. Overridden by non-default CONFIG_LSM.
264 config DEFAULT_SECURITY_SELINUX
265 bool "SELinux" if SECURITY_SELINUX=y
267 config DEFAULT_SECURITY_SMACK
268 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
270 config DEFAULT_SECURITY_TOMOYO
271 bool "TOMOYO" if SECURITY_TOMOYO=y
273 config DEFAULT_SECURITY_APPARMOR
274 bool "AppArmor" if SECURITY_APPARMOR=y
276 config DEFAULT_SECURITY_DAC
277 bool "Unix Discretionary Access Controls"
282 string "Ordered list of enabled LSMs"
283 default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor" if DEFAULT_SECURITY_SMACK
284 default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo" if DEFAULT_SECURITY_APPARMOR
285 default "lockdown,yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO
286 default "lockdown,yama,loadpin,safesetid,integrity" if DEFAULT_SECURITY_DAC
287 default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"
289 A comma-separated list of LSMs, in initialization order.
290 Any LSMs left off this list will be ignored. This can be
291 controlled at boot with the "lsm=" parameter.
293 If unsure, leave this as the default.
295 source "security/Kconfig.hardening"