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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
22config SECURITY
23 bool "Enable different security models"
24 depends on SYSFS
25 depends on MULTIUSER
26 help
27 This allows you to choose different security modules to be
28 configured into your kernel.
29
30 If this option is not selected, the default Linux security
31 model will be used.
32
33 If you are unsure how to answer this question, answer N.
34
35config SECURITY_WRITABLE_HOOKS
36 depends on SECURITY
37 bool
38 default n
39
40config SECURITYFS
41 bool "Enable the securityfs filesystem"
42 help
43 This will build the securityfs filesystem. It is currently used by
44 various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
45
46 If you are unsure how to answer this question, answer N.
47
48config SECURITY_NETWORK
49 bool "Socket and Networking Security Hooks"
50 depends on SECURITY
51 help
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.
56
57config SECURITY_INFINIBAND
58 bool "Infiniband Security Hooks"
59 depends on SECURITY && INFINIBAND
60 help
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.
65
66config SECURITY_NETWORK_XFRM
67 bool "XFRM (IPSec) Networking Security Hooks"
68 depends on XFRM && SECURITY_NETWORK
69 help
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
76 IPSec.
77 If you are unsure how to answer this question, answer N.
78
79config SECURITY_PATH
80 bool "Security hooks for pathname based access control"
81 depends on SECURITY
82 help
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.
87
88config INTEL_TXT
89 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
90 depends on HAVE_INTEL_TXT
91 help
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
96 will have no effect.
97
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.
104
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.
109
110 See <https://www.intel.com/technology/security/> for more information
111 about Intel(R) TXT.
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.
115
116 If you are unsure as to whether this is required, answer N.
117
118config 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)
122 default 65536
123 help
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.
127
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
133 systems running LSM.
134
135config HAVE_HARDENED_USERCOPY_ALLOCATOR
136 bool
137 help
138 The heap allocator implements __check_heap_object() for
139 validating memory ranges against heap object sizes in
140 support of CONFIG_HARDENED_USERCOPY.
141
142config HARDENED_USERCOPY
143 bool "Harden memory copies between kernel and userspace"
144 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
145 imply STRICT_DEVMEM
146 help
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 prevents entire classes
153 of heap overflow exploits and similar kernel memory exposures.
154
155config FORTIFY_SOURCE
156 bool "Harden common str/mem functions against buffer overflows"
157 depends on ARCH_HAS_FORTIFY_SOURCE
158 # https://bugs.llvm.org/show_bug.cgi?id=41459
159 depends on !CC_IS_CLANG || CLANG_VERSION >= 120001
160 # https://github.com/llvm/llvm-project/issues/53645
161 depends on !CC_IS_CLANG || !X86_32
162 help
163 Detect overflows of buffers in common string and memory functions
164 where the compiler can determine and validate the buffer sizes.
165
166config STATIC_USERMODEHELPER
167 bool "Force all usermode helper calls through a single binary"
168 help
169 By default, the kernel can call many different userspace
170 binary programs through the "usermode helper" kernel
171 interface. Some of these binaries are statically defined
172 either in the kernel code itself, or as a kernel configuration
173 option. However, some of these are dynamically created at
174 runtime, or can be modified after the kernel has started up.
175 To provide an additional layer of security, route all of these
176 calls through a single executable that can not have its name
177 changed.
178
179 Note, it is up to this single binary to then call the relevant
180 "real" usermode helper binary, based on the first argument
181 passed to it. If desired, this program can filter and pick
182 and choose what real programs are called.
183
184 If you wish for all usermode helper programs are to be
185 disabled, choose this option and then set
186 STATIC_USERMODEHELPER_PATH to an empty string.
187
188config STATIC_USERMODEHELPER_PATH
189 string "Path to the static usermode helper binary"
190 depends on STATIC_USERMODEHELPER
191 default "/sbin/usermode-helper"
192 help
193 The binary called by the kernel when any usermode helper
194 program is wish to be run. The "real" application's name will
195 be in the first argument passed to this program on the command
196 line.
197
198 If you wish for all usermode helper programs to be disabled,
199 specify an empty string here (i.e. "").
200
201source "security/selinux/Kconfig"
202source "security/smack/Kconfig"
203source "security/tomoyo/Kconfig"
204source "security/apparmor/Kconfig"
205source "security/loadpin/Kconfig"
206source "security/yama/Kconfig"
207source "security/safesetid/Kconfig"
208source "security/lockdown/Kconfig"
209source "security/landlock/Kconfig"
210
211source "security/integrity/Kconfig"
212
213choice
214 prompt "First legacy 'major LSM' to be initialized"
215 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
216 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
217 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
218 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
219 default DEFAULT_SECURITY_DAC
220
221 help
222 This choice is there only for converting CONFIG_DEFAULT_SECURITY
223 in old kernel configs to CONFIG_LSM in new kernel configs. Don't
224 change this choice unless you are creating a fresh kernel config,
225 for this choice will be ignored after CONFIG_LSM has been set.
226
227 Selects the legacy "major security module" that will be
228 initialized first. Overridden by non-default CONFIG_LSM.
229
230 config DEFAULT_SECURITY_SELINUX
231 bool "SELinux" if SECURITY_SELINUX=y
232
233 config DEFAULT_SECURITY_SMACK
234 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
235
236 config DEFAULT_SECURITY_TOMOYO
237 bool "TOMOYO" if SECURITY_TOMOYO=y
238
239 config DEFAULT_SECURITY_APPARMOR
240 bool "AppArmor" if SECURITY_APPARMOR=y
241
242 config DEFAULT_SECURITY_DAC
243 bool "Unix Discretionary Access Controls"
244
245endchoice
246
247config LSM
248 string "Ordered list of enabled LSMs"
249 default "landlock,lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
250 default "landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
251 default "landlock,lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
252 default "landlock,lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC
253 default "landlock,lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf"
254 help
255 A comma-separated list of LSMs, in initialization order.
256 Any LSMs left off this list will be ignored. This can be
257 controlled at boot with the "lsm=" parameter.
258
259 If unsure, leave this as the default.
260
261source "security/Kconfig.hardening"
262
263endmenu
264
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
22config SECURITY
23 bool "Enable different security models"
24 depends on SYSFS
25 depends on MULTIUSER
26 help
27 This allows you to choose different security modules to be
28 configured into your kernel.
29
30 If this option is not selected, the default Linux security
31 model will be used.
32
33 If you are unsure how to answer this question, answer N.
34
35config SECURITYFS
36 bool "Enable the securityfs filesystem"
37 help
38 This will build the securityfs filesystem. It is currently used by
39 various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
40
41 If you are unsure how to answer this question, answer N.
42
43config SECURITY_NETWORK
44 bool "Socket and Networking Security Hooks"
45 depends on SECURITY
46 help
47 This enables the socket and networking security hooks.
48 If enabled, a security module can use these hooks to
49 implement socket and networking access controls.
50 If you are unsure how to answer this question, answer N.
51
52config SECURITY_INFINIBAND
53 bool "Infiniband Security Hooks"
54 depends on SECURITY && INFINIBAND
55 help
56 This enables the Infiniband security hooks.
57 If enabled, a security module can use these hooks to
58 implement Infiniband access controls.
59 If you are unsure how to answer this question, answer N.
60
61config SECURITY_NETWORK_XFRM
62 bool "XFRM (IPSec) Networking Security Hooks"
63 depends on XFRM && SECURITY_NETWORK
64 help
65 This enables the XFRM (IPSec) networking security hooks.
66 If enabled, a security module can use these hooks to
67 implement per-packet access controls based on labels
68 derived from IPSec policy. Non-IPSec communications are
69 designated as unlabelled, and only sockets authorized
70 to communicate unlabelled data can send without using
71 IPSec.
72 If you are unsure how to answer this question, answer N.
73
74config SECURITY_PATH
75 bool "Security hooks for pathname based access control"
76 depends on SECURITY
77 help
78 This enables the security hooks for pathname based access control.
79 If enabled, a security module can use these hooks to
80 implement pathname based access controls.
81 If you are unsure how to answer this question, answer N.
82
83config INTEL_TXT
84 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
85 depends on HAVE_INTEL_TXT
86 help
87 This option enables support for booting the kernel with the
88 Trusted Boot (tboot) module. This will utilize
89 Intel(R) Trusted Execution Technology to perform a measured launch
90 of the kernel. If the system does not support Intel(R) TXT, this
91 will have no effect.
92
93 Intel TXT will provide higher assurance of system configuration and
94 initial state as well as data reset protection. This is used to
95 create a robust initial kernel measurement and verification, which
96 helps to ensure that kernel security mechanisms are functioning
97 correctly. This level of protection requires a root of trust outside
98 of the kernel itself.
99
100 Intel TXT also helps solve real end user concerns about having
101 confidence that their hardware is running the VMM or kernel that
102 it was configured with, especially since they may be responsible for
103 providing such assurances to VMs and services running on it.
104
105 See <https://www.intel.com/technology/security/> for more information
106 about Intel(R) TXT.
107 See <http://tboot.sourceforge.net> for more information about tboot.
108 See Documentation/arch/x86/intel_txt.rst for a description of how to enable
109 Intel TXT support in a kernel boot.
110
111 If you are unsure as to whether this is required, answer N.
112
113config LSM_MMAP_MIN_ADDR
114 int "Low address space for LSM to protect from user allocation"
115 depends on SECURITY && SECURITY_SELINUX
116 default 32768 if ARM || (ARM64 && COMPAT)
117 default 65536
118 help
119 This is the portion of low virtual memory which should be protected
120 from userspace allocation. Keeping a user from writing to low pages
121 can help reduce the impact of kernel NULL pointer bugs.
122
123 For most ia64, ppc64 and x86 users with lots of address space
124 a value of 65536 is reasonable and should cause no problems.
125 On arm and other archs it should not be higher than 32768.
126 Programs which use vm86 functionality or have some need to map
127 this low address space will need the permission specific to the
128 systems running LSM.
129
130config HARDENED_USERCOPY
131 bool "Harden memory copies between kernel and userspace"
132 imply STRICT_DEVMEM
133 help
134 This option checks for obviously wrong memory regions when
135 copying memory to/from the kernel (via copy_to_user() and
136 copy_from_user() functions) by rejecting memory ranges that
137 are larger than the specified heap object, span multiple
138 separately allocated pages, are not on the process stack,
139 or are part of the kernel text. This prevents entire classes
140 of heap overflow exploits and similar kernel memory exposures.
141
142config FORTIFY_SOURCE
143 bool "Harden common str/mem functions against buffer overflows"
144 depends on ARCH_HAS_FORTIFY_SOURCE
145 # https://bugs.llvm.org/show_bug.cgi?id=41459
146 depends on !CC_IS_CLANG || CLANG_VERSION >= 120001
147 # https://github.com/llvm/llvm-project/issues/53645
148 depends on !CC_IS_CLANG || !X86_32
149 help
150 Detect overflows of buffers in common string and memory functions
151 where the compiler can determine and validate the buffer sizes.
152
153config STATIC_USERMODEHELPER
154 bool "Force all usermode helper calls through a single binary"
155 help
156 By default, the kernel can call many different userspace
157 binary programs through the "usermode helper" kernel
158 interface. Some of these binaries are statically defined
159 either in the kernel code itself, or as a kernel configuration
160 option. However, some of these are dynamically created at
161 runtime, or can be modified after the kernel has started up.
162 To provide an additional layer of security, route all of these
163 calls through a single executable that can not have its name
164 changed.
165
166 Note, it is up to this single binary to then call the relevant
167 "real" usermode helper binary, based on the first argument
168 passed to it. If desired, this program can filter and pick
169 and choose what real programs are called.
170
171 If you wish for all usermode helper programs are to be
172 disabled, choose this option and then set
173 STATIC_USERMODEHELPER_PATH to an empty string.
174
175config STATIC_USERMODEHELPER_PATH
176 string "Path to the static usermode helper binary"
177 depends on STATIC_USERMODEHELPER
178 default "/sbin/usermode-helper"
179 help
180 The binary called by the kernel when any usermode helper
181 program is wish to be run. The "real" application's name will
182 be in the first argument passed to this program on the command
183 line.
184
185 If you wish for all usermode helper programs to be disabled,
186 specify an empty string here (i.e. "").
187
188source "security/selinux/Kconfig"
189source "security/smack/Kconfig"
190source "security/tomoyo/Kconfig"
191source "security/apparmor/Kconfig"
192source "security/loadpin/Kconfig"
193source "security/yama/Kconfig"
194source "security/safesetid/Kconfig"
195source "security/lockdown/Kconfig"
196source "security/landlock/Kconfig"
197
198source "security/integrity/Kconfig"
199
200choice
201 prompt "First legacy 'major LSM' to be initialized"
202 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
203 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
204 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
205 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
206 default DEFAULT_SECURITY_DAC
207
208 help
209 This choice is there only for converting CONFIG_DEFAULT_SECURITY
210 in old kernel configs to CONFIG_LSM in new kernel configs. Don't
211 change this choice unless you are creating a fresh kernel config,
212 for this choice will be ignored after CONFIG_LSM has been set.
213
214 Selects the legacy "major security module" that will be
215 initialized first. Overridden by non-default CONFIG_LSM.
216
217 config DEFAULT_SECURITY_SELINUX
218 bool "SELinux" if SECURITY_SELINUX=y
219
220 config DEFAULT_SECURITY_SMACK
221 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
222
223 config DEFAULT_SECURITY_TOMOYO
224 bool "TOMOYO" if SECURITY_TOMOYO=y
225
226 config DEFAULT_SECURITY_APPARMOR
227 bool "AppArmor" if SECURITY_APPARMOR=y
228
229 config DEFAULT_SECURITY_DAC
230 bool "Unix Discretionary Access Controls"
231
232endchoice
233
234config LSM
235 string "Ordered list of enabled LSMs"
236 default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
237 default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
238 default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
239 default "landlock,lockdown,yama,loadpin,safesetid,bpf" if DEFAULT_SECURITY_DAC
240 default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,bpf"
241 help
242 A comma-separated list of LSMs, in initialization order.
243 Any LSMs left off this list, except for those with order
244 LSM_ORDER_FIRST and LSM_ORDER_LAST, which are always enabled
245 if selected in the kernel configuration, will be ignored.
246 This can be controlled at boot with the "lsm=" parameter.
247
248 If unsure, leave this as the default.
249
250source "security/Kconfig.hardening"
251
252endmenu
253