2 # Security configuration
5 menu "Security options"
7 source security/keys/Kconfig
9 config SECURITY_DMESG_RESTRICT
10 bool "Restrict unprivileged access to the kernel syslog"
13 This enforces restrictions on unprivileged users reading the kernel
16 If this option is not selected, no restrictions will be enforced
17 unless the dmesg_restrict sysctl is explicitly set to (1).
19 If you are unsure how to answer this question, answer N.
21 config SECURITY_PERF_EVENTS_RESTRICT
22 bool "Restrict unprivileged use of performance events"
23 depends on PERF_EVENTS
25 If you say Y here, the kernel.perf_event_paranoid sysctl
26 will be set to 3 by default, and no unprivileged use of the
27 perf_event_open syscall will be permitted unless it is
31 bool "Enable different security models"
35 This allows you to choose different security modules to be
36 configured into your kernel.
38 If this option is not selected, the default Linux security
41 If you are unsure how to answer this question, answer N.
43 config SECURITY_WRITABLE_HOOKS
48 config SECURITY_STACKING
49 bool "Security module stacking"
52 Allows multiple major security modules to be stacked.
53 Modules are invoked in the order registered with a
54 "bail on fail" policy, in which the infrastructure
55 will stop processing once a denial is detected. Not
56 all modules can be stacked. SELinux and Smack are
57 known to be incompatible. User space components may
58 have trouble identifying the security module providing
61 If you select this option you will have to select which
62 of the stackable modules you wish to be active. The
63 "Default security module" will be ignored. The boot line
64 "security=" option can be used to specify that one of
65 the modules identifed for stacking should be used instead
68 If you are unsure how to answer this question, answer N.
70 config SECURITY_LSM_DEBUG
71 bool "Enable debugging of the LSM infrastructure"
74 This allows you to choose debug messages related to
75 security modules configured into your kernel. These
76 messages may be helpful in determining how a security
77 module is using security blobs.
79 If you are unsure how to answer this question, answer N.
82 bool "Enable the securityfs filesystem"
84 This will build the securityfs filesystem. It is currently used by
85 the TPM bios character driver and IMA, an integrity provider. It is
86 not used by SELinux or SMACK.
88 If you are unsure how to answer this question, answer N.
90 config SECURITY_NETWORK
91 bool "Socket and Networking Security Hooks"
94 This enables the socket and networking security hooks.
95 If enabled, a security module can use these hooks to
96 implement socket and networking access controls.
97 If you are unsure how to answer this question, answer N.
99 config SECURITY_INFINIBAND
100 bool "Infiniband Security Hooks"
101 depends on SECURITY && INFINIBAND
103 This enables the Infiniband security hooks.
104 If enabled, a security module can use these hooks to
105 implement Infiniband access controls.
106 If you are unsure how to answer this question, answer N.
108 config SECURITY_NETWORK_XFRM
109 bool "XFRM (IPSec) Networking Security Hooks"
110 depends on XFRM && SECURITY_NETWORK
112 This enables the XFRM (IPSec) networking security hooks.
113 If enabled, a security module can use these hooks to
114 implement per-packet access controls based on labels
115 derived from IPSec policy. Non-IPSec communications are
116 designated as unlabelled, and only sockets authorized
117 to communicate unlabelled data can send without using
119 If you are unsure how to answer this question, answer N.
122 bool "Security hooks for pathname based access control"
125 This enables the security hooks for pathname based access control.
126 If enabled, a security module can use these hooks to
127 implement pathname based access controls.
128 If you are unsure how to answer this question, answer N.
131 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
132 depends on HAVE_INTEL_TXT
134 This option enables support for booting the kernel with the
135 Trusted Boot (tboot) module. This will utilize
136 Intel(R) Trusted Execution Technology to perform a measured launch
137 of the kernel. If the system does not support Intel(R) TXT, this
140 Intel TXT will provide higher assurance of system configuration and
141 initial state as well as data reset protection. This is used to
142 create a robust initial kernel measurement and verification, which
143 helps to ensure that kernel security mechanisms are functioning
144 correctly. This level of protection requires a root of trust outside
145 of the kernel itself.
147 Intel TXT also helps solve real end user concerns about having
148 confidence that their hardware is running the VMM or kernel that
149 it was configured with, especially since they may be responsible for
150 providing such assurances to VMs and services running on it.
152 See <http://www.intel.com/technology/security/> for more information
154 See <http://tboot.sourceforge.net> for more information about tboot.
155 See Documentation/intel_txt.txt for a description of how to enable
156 Intel TXT support in a kernel boot.
158 If you are unsure as to whether this is required, answer N.
160 config LSM_MMAP_MIN_ADDR
161 int "Low address space for LSM to protect from user allocation"
162 depends on SECURITY && SECURITY_SELINUX
163 default 32768 if ARM || (ARM64 && COMPAT)
166 This is the portion of low virtual memory which should be protected
167 from userspace allocation. Keeping a user from writing to low pages
168 can help reduce the impact of kernel NULL pointer bugs.
170 For most ia64, ppc64 and x86 users with lots of address space
171 a value of 65536 is reasonable and should cause no problems.
172 On arm and other archs it should not be higher than 32768.
173 Programs which use vm86 functionality or have some need to map
174 this low address space will need the permission specific to the
177 config HAVE_HARDENED_USERCOPY_ALLOCATOR
180 The heap allocator implements __check_heap_object() for
181 validating memory ranges against heap object sizes in
182 support of CONFIG_HARDENED_USERCOPY.
184 config HARDENED_USERCOPY
185 bool "Harden memory copies between kernel and userspace"
186 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
189 This option checks for obviously wrong memory regions when
190 copying memory to/from the kernel (via copy_to_user() and
191 copy_from_user() functions) by rejecting memory ranges that
192 are larger than the specified heap object, span multiple
193 separately allocated pages, are not on the process stack,
194 or are part of the kernel text. This kills entire classes
195 of heap overflow exploits and similar kernel memory exposures.
197 config HARDENED_USERCOPY_PAGESPAN
198 bool "Refuse to copy allocations that span multiple pages"
199 depends on HARDENED_USERCOPY
202 When a multi-page allocation is done without __GFP_COMP,
203 hardened usercopy will reject attempts to copy it. There are,
204 however, several cases of this in the kernel that have not all
205 been removed. This config is intended to be used only while
206 trying to find such users.
208 config FORTIFY_SOURCE
209 bool "Harden common str/mem functions against buffer overflows"
210 depends on ARCH_HAS_FORTIFY_SOURCE
212 Detect overflows of buffers in common string and memory functions
213 where the compiler can determine and validate the buffer sizes.
215 config STATIC_USERMODEHELPER
216 bool "Force all usermode helper calls through a single binary"
218 By default, the kernel can call many different userspace
219 binary programs through the "usermode helper" kernel
220 interface. Some of these binaries are statically defined
221 either in the kernel code itself, or as a kernel configuration
222 option. However, some of these are dynamically created at
223 runtime, or can be modified after the kernel has started up.
224 To provide an additional layer of security, route all of these
225 calls through a single executable that can not have its name
228 Note, it is up to this single binary to then call the relevant
229 "real" usermode helper binary, based on the first argument
230 passed to it. If desired, this program can filter and pick
231 and choose what real programs are called.
233 If you wish for all usermode helper programs are to be
234 disabled, choose this option and then set
235 STATIC_USERMODEHELPER_PATH to an empty string.
237 config STATIC_USERMODEHELPER_PATH
238 string "Path to the static usermode helper binary"
239 depends on STATIC_USERMODEHELPER
240 default "/sbin/usermode-helper"
242 The binary called by the kernel when any usermode helper
243 program is wish to be run. The "real" application's name will
244 be in the first argument passed to this program on the command
247 If you wish for all usermode helper programs to be disabled,
248 specify an empty string here (i.e. "").
250 config LOCK_DOWN_KERNEL
251 bool "Allow the kernel to be 'locked down'"
253 Allow the kernel to be locked down under certain circumstances, for
254 instance if UEFI secure boot is enabled. Locking down the kernel
255 turns off various features that might otherwise allow access to the
256 kernel image (eg. setting MSR registers).
258 config ALLOW_LOCKDOWN_LIFT
261 Allow the lockdown on a kernel to be lifted, thereby restoring the
262 ability of userspace to access the kernel image (eg. by SysRq+x under
265 source security/selinux/Kconfig
266 source security/smack/Kconfig
267 source security/tomoyo/Kconfig
268 source security/apparmor/Kconfig
269 source security/loadpin/Kconfig
270 source security/yama/Kconfig
272 source security/integrity/Kconfig
274 menu "Security Module Selection"
275 visible if !SECURITY_STACKING
278 prompt "Default security module"
279 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
280 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
281 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
282 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
283 default DEFAULT_SECURITY_DAC
286 Select the security module that will be used by default if the
287 kernel parameter security= is not specified.
289 config DEFAULT_SECURITY_SELINUX
290 bool "SELinux" if SECURITY_SELINUX=y
292 config DEFAULT_SECURITY_SMACK
293 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
295 config DEFAULT_SECURITY_TOMOYO
296 bool "TOMOYO" if SECURITY_TOMOYO=y
298 config DEFAULT_SECURITY_APPARMOR
299 bool "AppArmor" if SECURITY_APPARMOR=y
301 config DEFAULT_SECURITY_DAC
302 bool "Unix Discretionary Access Controls"
306 config DEFAULT_SECURITY
308 default "selinux" if DEFAULT_SECURITY_SELINUX
309 default "smack" if DEFAULT_SECURITY_SMACK
310 default "tomoyo" if DEFAULT_SECURITY_TOMOYO
311 default "apparmor" if DEFAULT_SECURITY_APPARMOR
312 default "" if DEFAULT_SECURITY_DAC
316 menu "Security Module Stack"
317 visible if SECURITY_STACKING
320 prompt "mutually exclusive LSMs"
321 default SECURITY_NO_EXCLUSIVE_LSM
323 config SECURITY_NO_EXCLUSIVE_LSM
326 Do no add an LSM to is mutually exclusive to the stack."
327 config SECURITY_SELINUX_STACKED
328 bool "SELinux" if SECURITY_SELINUX=y
330 Add the SELinux security module to the stack.
331 Please be sure your user space code is accomodating of
332 this security module.
333 Ensure that your network configuration is compatible
334 with your combination of security modules.
336 Incompatible with Smack being stacked.
338 If you are unsure how to answer this question, answer N.
340 config SECURITY_SMACK_STACKED
341 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
343 Add the Smack security module to the stack.
344 Please be sure your user space code is accomodating of
345 this security module.
346 Ensure that your network configuration is compatible
347 with your combination of security modules.
349 Incompatible with SeLinux being stacked.
351 If you are unsure how to answer this question, answer N.
354 config SECURITY_TOMOYO_STACKED
355 bool "TOMOYO support is enabled by default"
356 depends on SECURITY_TOMOYO && SECURITY_STACKING
359 This option instructs the system to use the TOMOYO checks.
360 If not selected the module will not be invoked.
361 Stacked security modules may interact in unexpected ways.
362 Please be sure your user space code is accomodating of
363 multiple security modules.
365 If you are unsure how to answer this question, answer N.
367 config SECURITY_APPARMOR_STACKED
368 bool "AppArmor support is enabled by default"
369 depends on SECURITY_APPARMOR && SECURITY_STACKING
372 This option instructs the system to use the AppArmor checks.
373 If not selected the module will not be invoked.
374 Stacked security modules may interact in unexpected ways.
375 Please be sure your user space code is accomodating of
376 multiple security modules.
378 If you are unsure how to answer this question, answer N.