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 SECURITY_INFINIBAND
58 bool "Infiniband Security Hooks"
59 depends on SECURITY && INFINIBAND
61 This enables the Infiniband security hooks.
62 If enabled, a security module can use these hooks to
63 implement Infiniband access controls.
64 If you are unsure how to answer this question, answer N.
66 config SECURITY_NETWORK_XFRM
67 bool "XFRM (IPSec) Networking Security Hooks"
68 depends on XFRM && SECURITY_NETWORK
70 This enables the XFRM (IPSec) networking security hooks.
71 If enabled, a security module can use these hooks to
72 implement per-packet access controls based on labels
73 derived from IPSec policy. Non-IPSec communications are
74 designated as unlabelled, and only sockets authorized
75 to communicate unlabelled data can send without using
77 If you are unsure how to answer this question, answer N.
80 bool "Security hooks for pathname based access control"
83 This enables the security hooks for pathname based access control.
84 If enabled, a security module can use these hooks to
85 implement pathname based access controls.
86 If you are unsure how to answer this question, answer N.
89 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
90 depends on HAVE_INTEL_TXT
92 This option enables support for booting the kernel with the
93 Trusted Boot (tboot) module. This will utilize
94 Intel(R) Trusted Execution Technology to perform a measured launch
95 of the kernel. If the system does not support Intel(R) TXT, this
98 Intel TXT will provide higher assurance of system configuration and
99 initial state as well as data reset protection. This is used to
100 create a robust initial kernel measurement and verification, which
101 helps to ensure that kernel security mechanisms are functioning
102 correctly. This level of protection requires a root of trust outside
103 of the kernel itself.
105 Intel TXT also helps solve real end user concerns about having
106 confidence that their hardware is running the VMM or kernel that
107 it was configured with, especially since they may be responsible for
108 providing such assurances to VMs and services running on it.
110 See <https://www.intel.com/technology/security/> for more information
112 See <http://tboot.sourceforge.net> for more information about tboot.
113 See Documentation/x86/intel_txt.rst for a description of how to enable
114 Intel TXT support in a kernel boot.
116 If you are unsure as to whether this is required, answer N.
118 config LSM_MMAP_MIN_ADDR
119 int "Low address space for LSM to protect from user allocation"
120 depends on SECURITY && SECURITY_SELINUX
121 default 32768 if ARM || (ARM64 && COMPAT)
124 This is the portion of low virtual memory which should be protected
125 from userspace allocation. Keeping a user from writing to low pages
126 can help reduce the impact of kernel NULL pointer bugs.
128 For most ia64, ppc64 and x86 users with lots of address space
129 a value of 65536 is reasonable and should cause no problems.
130 On arm and other archs it should not be higher than 32768.
131 Programs which use vm86 functionality or have some need to map
132 this low address space will need the permission specific to the
135 config HAVE_HARDENED_USERCOPY_ALLOCATOR
138 The heap allocator implements __check_heap_object() for
139 validating memory ranges against heap object sizes in
140 support of CONFIG_HARDENED_USERCOPY.
142 config HARDENED_USERCOPY
143 bool "Harden memory copies between kernel and userspace"
144 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
147 This option checks for obviously wrong memory regions when
148 copying memory to/from the kernel (via copy_to_user() and
149 copy_from_user() functions) by rejecting memory ranges that
150 are larger than the specified heap object, span multiple
151 separately allocated pages, are not on the process stack,
152 or are part of the kernel text. This kills entire classes
153 of heap overflow exploits and similar kernel memory exposures.
155 config HARDENED_USERCOPY_FALLBACK
156 bool "Allow usercopy whitelist violations to fallback to object size"
157 depends on HARDENED_USERCOPY
160 This is a temporary option that allows missing usercopy whitelists
161 to be discovered via a WARN() to the kernel log, instead of
162 rejecting the copy, falling back to non-whitelisted hardened
163 usercopy that checks the slab allocation size instead of the
164 whitelist size. This option will be removed once it seems like
165 all missing usercopy whitelists have been identified and fixed.
166 Booting with "slab_common.usercopy_fallback=Y/N" can change
169 config HARDENED_USERCOPY_PAGESPAN
170 bool "Refuse to copy allocations that span multiple pages"
171 depends on HARDENED_USERCOPY
174 When a multi-page allocation is done without __GFP_COMP,
175 hardened usercopy will reject attempts to copy it. There are,
176 however, several cases of this in the kernel that have not all
177 been removed. This config is intended to be used only while
178 trying to find such users.
180 config FORTIFY_SOURCE
181 bool "Harden common str/mem functions against buffer overflows"
182 depends on ARCH_HAS_FORTIFY_SOURCE
183 # https://bugs.llvm.org/show_bug.cgi?id=50322
184 # https://bugs.llvm.org/show_bug.cgi?id=41459
185 depends on !CC_IS_CLANG
187 Detect overflows of buffers in common string and memory functions
188 where the compiler can determine and validate the buffer sizes.
190 config STATIC_USERMODEHELPER
191 bool "Force all usermode helper calls through a single binary"
193 By default, the kernel can call many different userspace
194 binary programs through the "usermode helper" kernel
195 interface. Some of these binaries are statically defined
196 either in the kernel code itself, or as a kernel configuration
197 option. However, some of these are dynamically created at
198 runtime, or can be modified after the kernel has started up.
199 To provide an additional layer of security, route all of these
200 calls through a single executable that can not have its name
203 Note, it is up to this single binary to then call the relevant
204 "real" usermode helper binary, based on the first argument
205 passed to it. If desired, this program can filter and pick
206 and choose what real programs are called.
208 If you wish for all usermode helper programs are to be
209 disabled, choose this option and then set
210 STATIC_USERMODEHELPER_PATH to an empty string.
212 config STATIC_USERMODEHELPER_PATH
213 string "Path to the static usermode helper binary"
214 depends on STATIC_USERMODEHELPER
215 default "/sbin/usermode-helper"
217 The binary called by the kernel when any usermode helper
218 program is wish to be run. The "real" application's name will
219 be in the first argument passed to this program on the command
222 If you wish for all usermode helper programs to be disabled,
223 specify an empty string here (i.e. "").
225 source "security/selinux/Kconfig"
226 source "security/smack/Kconfig"
227 source "security/tomoyo/Kconfig"
228 source "security/apparmor/Kconfig"
229 source "security/loadpin/Kconfig"
230 source "security/yama/Kconfig"
231 source "security/safesetid/Kconfig"
232 source "security/lockdown/Kconfig"
233 source "security/landlock/Kconfig"
235 source "security/integrity/Kconfig"
238 prompt "First legacy 'major LSM' to be initialized"
239 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
240 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
241 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
242 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
243 default DEFAULT_SECURITY_DAC
246 This choice is there only for converting CONFIG_DEFAULT_SECURITY
247 in old kernel configs to CONFIG_LSM in new kernel configs. Don't
248 change this choice unless you are creating a fresh kernel config,
249 for this choice will be ignored after CONFIG_LSM has been set.
251 Selects the legacy "major security module" that will be
252 initialized first. Overridden by non-default CONFIG_LSM.
254 config DEFAULT_SECURITY_SELINUX
255 bool "SELinux" if SECURITY_SELINUX=y
257 config DEFAULT_SECURITY_SMACK
258 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
260 config DEFAULT_SECURITY_TOMOYO
261 bool "TOMOYO" if SECURITY_TOMOYO=y
263 config DEFAULT_SECURITY_APPARMOR
264 bool "AppArmor" if SECURITY_APPARMOR=y
266 config DEFAULT_SECURITY_DAC
267 bool "Unix Discretionary Access Controls"
272 string "Ordered list of enabled LSMs"
273 default "landlock,lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
274 default "landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
275 default "landlock,lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
276 default "landlock,lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC
277 default "landlock,lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf"
279 A comma-separated list of LSMs, in initialization order.
280 Any LSMs left off this list will be ignored. This can be
281 controlled at boot with the "lsm=" parameter.
283 If unsure, leave this as the default.
285 source "security/Kconfig.hardening"