6menu "Security options"
11 bool "Restrict unprivileged access to the kernel syslog"
12 default n
14 This enforces restrictions on unprivileged users reading the kernel
15 syslog via dmesg(8).
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"
24 depends on SYSFS
25 depends on MULTIUSER
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
31 model will be used.
33 If you are unsure how to answer this question, answer N.
36 depends on SECURITY
38 default n
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.
49 bool "Socket and Networking Security Hooks"
50 depends on SECURITY
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.
58 bool "Remove the kernel mapping in user mode"
59 default y
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
64 into userspace.
66 See Documentation/x86/pti.rst for more details.
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.
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"
92 depends on SECURITY
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
107 will have no effect.
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
122 about Intel(R) TXT.
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.
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)
133 default 65536
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
144 systems running LSM.
149 The heap allocator implements __check_heap_object() for
150 validating memory ranges against heap object sizes in
151 support of CONFIG_HARDENED_USERCOPY.
154 bool "Harden memory copies between kernel and userspace"
155 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
156 imply STRICT_DEVMEM
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.
167 bool "Allow usercopy whitelist violations to fallback to object size"
168 depends on HARDENED_USERCOPY
169 default y
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
178 this setting.
181 bool "Refuse to copy allocations that span multiple pages"
182 depends on HARDENED_USERCOPY
183 depends on EXPERT
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.
192 bool "Harden common str/mem functions against buffer overflows"
193 depends on ARCH_HAS_FORTIFY_SOURCE
195 Detect overflows of buffers in common string and memory functions
196 where the compiler can determine and validate the buffer sizes.
199 bool "Force all usermode helper calls through a single binary"
201 By default, the kernel can call many different userspace
202 binary programs through the "usermode helper" kernel
203 interface. Some of these binaries are statically defined
204 either in the kernel code itself, or as a kernel configuration
205 option. However, some of these are dynamically created at
206 runtime, or can be modified after the kernel has started up.
207 To provide an additional layer of security, route all of these
208 calls through a single executable that can not have its name
211 Note, it is up to this single binary to then call the relevant
212 "real" usermode helper binary, based on the first argument
213 passed to it. If desired, this program can filter and pick
214 and choose what real programs are called.
216 If you wish for all usermode helper programs are to be
217 disabled, choose this option and then set
218 STATIC_USERMODEHELPER_PATH to an empty string.
221 string "Path to the static usermode helper binary"
222 depends on STATIC_USERMODEHELPER
223 default "/sbin/usermode-helper"
225 The binary called by the kernel when any usermode helper
226 program is wish to be run. The "real" application's name will
227 be in the first argument passed to this program on the command
230 If you wish for all usermode helper programs to be disabled,
231 specify an empty string here (i.e. "").
245 prompt "First legacy 'major LSM' to be initialized"
246 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
247 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
248 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
249 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
250 default DEFAULT_SECURITY_DAC
253 This choice is there only for converting CONFIG_DEFAULT_SECURITY
254 in old kernel configs to CONFIG_LSM in new kernel configs. Don't
255 change this choice unless you are creating a fresh kernel config,
256 for this choice will be ignored after CONFIG_LSM has been set.
258 Selects the legacy "major security module" that will be
259 initialized first. Overridden by non-default CONFIG_LSM.
261 config DEFAULT_SECURITY_SELINUX
262 bool "SELinux" if SECURITY_SELINUX=y
264 config DEFAULT_SECURITY_SMACK
265 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
267 config DEFAULT_SECURITY_TOMOYO
268 bool "TOMOYO" if SECURITY_TOMOYO=y
270 config DEFAULT_SECURITY_APPARMOR
271 bool "AppArmor" if SECURITY_APPARMOR=y
273 config DEFAULT_SECURITY_DAC
274 bool "Unix Discretionary Access Controls"
279 string "Ordered list of enabled LSMs"
280 default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor" if DEFAULT_SECURITY_SMACK
281 default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo" if DEFAULT_SECURITY_APPARMOR
282 default "lockdown,yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO
283 default "lockdown,yama,loadpin,safesetid,integrity" if DEFAULT_SECURITY_DAC
284 default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"
286 A comma-separated list of LSMs, in initialization order.
287 Any LSMs left off this list will be ignored. This can be
288 controlled at boot with the "lsm=" parameter.
290 If unsure, leave this as the default.