1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 # 2 #
3 # Security configuration 3 # Security configuration
4 # 4 #
5 5
6 menu "Security options" 6 menu "Security options"
7 7
8 source "security/keys/Kconfig" 8 source "security/keys/Kconfig"
9 9
10 config SECURITY_DMESG_RESTRICT 10 config SECURITY_DMESG_RESTRICT
11 bool "Restrict unprivileged access to 11 bool "Restrict unprivileged access to the kernel syslog"
12 default n 12 default n
13 help 13 help
14 This enforces restrictions on unpriv 14 This enforces restrictions on unprivileged users reading the kernel
15 syslog via dmesg(8). 15 syslog via dmesg(8).
16 16
17 If this option is not selected, no r 17 If this option is not selected, no restrictions will be enforced
18 unless the dmesg_restrict sysctl is 18 unless the dmesg_restrict sysctl is explicitly set to (1).
19 19
20 If you are unsure how to answer this 20 If you are unsure how to answer this question, answer N.
21 21
22 choice <<
23 prompt "Allow /proc/pid/mem access ove <<
24 default PROC_MEM_ALWAYS_FORCE <<
25 help <<
26 Traditionally /proc/pid/mem allows u <<
27 permissions for users like ptrace, a <<
28 capability. <<
29 <<
30 This allows people to limit that - e <<
31 require actual active ptrace attachm <<
32 <<
33 Defaults to the traditional behavior <<
34 <<
35 config PROC_MEM_ALWAYS_FORCE <<
36 bool "Traditional /proc/pid/mem behavi <<
37 help <<
38 This allows /proc/pid/mem accesses t <<
39 permissions if you have ptrace acces <<
40 <<
41 config PROC_MEM_FORCE_PTRACE <<
42 bool "Require active ptrace() use for <<
43 help <<
44 This allows /proc/pid/mem accesses t <<
45 permissions for active ptracers like <<
46 <<
47 config PROC_MEM_NO_FORCE <<
48 bool "Never" <<
49 help <<
50 Never override memory mapping permis <<
51 <<
52 endchoice <<
53 <<
54 config SECURITY 22 config SECURITY
55 bool "Enable different security models 23 bool "Enable different security models"
56 depends on SYSFS 24 depends on SYSFS
57 depends on MULTIUSER 25 depends on MULTIUSER
58 help 26 help
59 This allows you to choose different 27 This allows you to choose different security modules to be
60 configured into your kernel. 28 configured into your kernel.
61 29
62 If this option is not selected, the 30 If this option is not selected, the default Linux security
63 model will be used. 31 model will be used.
64 32
65 If you are unsure how to answer this 33 If you are unsure how to answer this question, answer N.
66 34
67 config SECURITYFS 35 config SECURITYFS
68 bool "Enable the securityfs filesystem 36 bool "Enable the securityfs filesystem"
69 help 37 help
70 This will build the securityfs files 38 This will build the securityfs filesystem. It is currently used by
71 various security modules (AppArmor, 39 various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
72 40
73 If you are unsure how to answer this 41 If you are unsure how to answer this question, answer N.
74 42
75 config SECURITY_NETWORK 43 config SECURITY_NETWORK
76 bool "Socket and Networking Security H 44 bool "Socket and Networking Security Hooks"
77 depends on SECURITY 45 depends on SECURITY
78 help 46 help
79 This enables the socket and networki 47 This enables the socket and networking security hooks.
80 If enabled, a security module can us 48 If enabled, a security module can use these hooks to
81 implement socket and networking acce 49 implement socket and networking access controls.
82 If you are unsure how to answer this 50 If you are unsure how to answer this question, answer N.
83 51
84 config SECURITY_INFINIBAND 52 config SECURITY_INFINIBAND
85 bool "Infiniband Security Hooks" 53 bool "Infiniband Security Hooks"
86 depends on SECURITY && INFINIBAND 54 depends on SECURITY && INFINIBAND
87 help 55 help
88 This enables the Infiniband security 56 This enables the Infiniband security hooks.
89 If enabled, a security module can us 57 If enabled, a security module can use these hooks to
90 implement Infiniband access controls 58 implement Infiniband access controls.
91 If you are unsure how to answer this 59 If you are unsure how to answer this question, answer N.
92 60
93 config SECURITY_NETWORK_XFRM 61 config SECURITY_NETWORK_XFRM
94 bool "XFRM (IPSec) Networking Security 62 bool "XFRM (IPSec) Networking Security Hooks"
95 depends on XFRM && SECURITY_NETWORK 63 depends on XFRM && SECURITY_NETWORK
96 help 64 help
97 This enables the XFRM (IPSec) networ 65 This enables the XFRM (IPSec) networking security hooks.
98 If enabled, a security module can us 66 If enabled, a security module can use these hooks to
99 implement per-packet access controls 67 implement per-packet access controls based on labels
100 derived from IPSec policy. Non-IPSe 68 derived from IPSec policy. Non-IPSec communications are
101 designated as unlabelled, and only s 69 designated as unlabelled, and only sockets authorized
102 to communicate unlabelled data can s 70 to communicate unlabelled data can send without using
103 IPSec. 71 IPSec.
104 If you are unsure how to answer this 72 If you are unsure how to answer this question, answer N.
105 73
106 config SECURITY_PATH 74 config SECURITY_PATH
107 bool "Security hooks for pathname base 75 bool "Security hooks for pathname based access control"
108 depends on SECURITY 76 depends on SECURITY
109 help 77 help
110 This enables the security hooks for 78 This enables the security hooks for pathname based access control.
111 If enabled, a security module can us 79 If enabled, a security module can use these hooks to
112 implement pathname based access cont 80 implement pathname based access controls.
113 If you are unsure how to answer this 81 If you are unsure how to answer this question, answer N.
114 82
115 config INTEL_TXT 83 config INTEL_TXT
116 bool "Enable Intel(R) Trusted Executio 84 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
117 depends on HAVE_INTEL_TXT 85 depends on HAVE_INTEL_TXT
118 help 86 help
119 This option enables support for boot 87 This option enables support for booting the kernel with the
120 Trusted Boot (tboot) module. This wi 88 Trusted Boot (tboot) module. This will utilize
121 Intel(R) Trusted Execution Technolog 89 Intel(R) Trusted Execution Technology to perform a measured launch
122 of the kernel. If the system does no 90 of the kernel. If the system does not support Intel(R) TXT, this
123 will have no effect. 91 will have no effect.
124 92
125 Intel TXT will provide higher assura 93 Intel TXT will provide higher assurance of system configuration and
126 initial state as well as data reset 94 initial state as well as data reset protection. This is used to
127 create a robust initial kernel measu 95 create a robust initial kernel measurement and verification, which
128 helps to ensure that kernel security 96 helps to ensure that kernel security mechanisms are functioning
129 correctly. This level of protection 97 correctly. This level of protection requires a root of trust outside
130 of the kernel itself. 98 of the kernel itself.
131 99
132 Intel TXT also helps solve real end 100 Intel TXT also helps solve real end user concerns about having
133 confidence that their hardware is ru 101 confidence that their hardware is running the VMM or kernel that
134 it was configured with, especially s 102 it was configured with, especially since they may be responsible for
135 providing such assurances to VMs and 103 providing such assurances to VMs and services running on it.
136 104
137 See <https://www.intel.com/technolog 105 See <https://www.intel.com/technology/security/> for more information
138 about Intel(R) TXT. 106 about Intel(R) TXT.
139 See <http://tboot.sourceforge.net> f 107 See <http://tboot.sourceforge.net> for more information about tboot.
140 See Documentation/arch/x86/intel_txt 108 See Documentation/arch/x86/intel_txt.rst for a description of how to enable
141 Intel TXT support in a kernel boot. 109 Intel TXT support in a kernel boot.
142 110
143 If you are unsure as to whether this 111 If you are unsure as to whether this is required, answer N.
144 112
145 config LSM_MMAP_MIN_ADDR 113 config LSM_MMAP_MIN_ADDR
146 int "Low address space for LSM to prot 114 int "Low address space for LSM to protect from user allocation"
147 depends on SECURITY && SECURITY_SELINU 115 depends on SECURITY && SECURITY_SELINUX
148 default 32768 if ARM || (ARM64 && COMP 116 default 32768 if ARM || (ARM64 && COMPAT)
149 default 65536 117 default 65536
150 help 118 help
151 This is the portion of low virtual m 119 This is the portion of low virtual memory which should be protected
152 from userspace allocation. Keeping 120 from userspace allocation. Keeping a user from writing to low pages
153 can help reduce the impact of kernel 121 can help reduce the impact of kernel NULL pointer bugs.
154 122
155 For most ia64, ppc64 and x86 users w 123 For most ia64, ppc64 and x86 users with lots of address space
156 a value of 65536 is reasonable and s 124 a value of 65536 is reasonable and should cause no problems.
157 On arm and other archs it should not 125 On arm and other archs it should not be higher than 32768.
158 Programs which use vm86 functionalit 126 Programs which use vm86 functionality or have some need to map
159 this low address space will need the 127 this low address space will need the permission specific to the
160 systems running LSM. 128 systems running LSM.
161 129
162 config HARDENED_USERCOPY 130 config HARDENED_USERCOPY
163 bool "Harden memory copies between ker 131 bool "Harden memory copies between kernel and userspace"
164 imply STRICT_DEVMEM 132 imply STRICT_DEVMEM
165 help 133 help
166 This option checks for obviously wro 134 This option checks for obviously wrong memory regions when
167 copying memory to/from the kernel (v 135 copying memory to/from the kernel (via copy_to_user() and
168 copy_from_user() functions) by rejec 136 copy_from_user() functions) by rejecting memory ranges that
169 are larger than the specified heap o 137 are larger than the specified heap object, span multiple
170 separately allocated pages, are not 138 separately allocated pages, are not on the process stack,
171 or are part of the kernel text. This 139 or are part of the kernel text. This prevents entire classes
172 of heap overflow exploits and simila 140 of heap overflow exploits and similar kernel memory exposures.
173 141
174 config FORTIFY_SOURCE 142 config FORTIFY_SOURCE
175 bool "Harden common str/mem functions 143 bool "Harden common str/mem functions against buffer overflows"
176 depends on ARCH_HAS_FORTIFY_SOURCE 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
177 # https://github.com/llvm/llvm-project 147 # https://github.com/llvm/llvm-project/issues/53645
178 depends on !CC_IS_CLANG || !X86_32 148 depends on !CC_IS_CLANG || !X86_32
179 help 149 help
180 Detect overflows of buffers in commo 150 Detect overflows of buffers in common string and memory functions
181 where the compiler can determine and 151 where the compiler can determine and validate the buffer sizes.
182 152
183 config STATIC_USERMODEHELPER 153 config STATIC_USERMODEHELPER
184 bool "Force all usermode helper calls 154 bool "Force all usermode helper calls through a single binary"
185 help 155 help
186 By default, the kernel can call many 156 By default, the kernel can call many different userspace
187 binary programs through the "usermod 157 binary programs through the "usermode helper" kernel
188 interface. Some of these binaries a 158 interface. Some of these binaries are statically defined
189 either in the kernel code itself, or 159 either in the kernel code itself, or as a kernel configuration
190 option. However, some of these are 160 option. However, some of these are dynamically created at
191 runtime, or can be modified after th 161 runtime, or can be modified after the kernel has started up.
192 To provide an additional layer of se 162 To provide an additional layer of security, route all of these
193 calls through a single executable th 163 calls through a single executable that can not have its name
194 changed. 164 changed.
195 165
196 Note, it is up to this single binary 166 Note, it is up to this single binary to then call the relevant
197 "real" usermode helper binary, based 167 "real" usermode helper binary, based on the first argument
198 passed to it. If desired, this prog 168 passed to it. If desired, this program can filter and pick
199 and choose what real programs are ca 169 and choose what real programs are called.
200 170
201 If you wish for all usermode helper 171 If you wish for all usermode helper programs are to be
202 disabled, choose this option and the 172 disabled, choose this option and then set
203 STATIC_USERMODEHELPER_PATH to an emp 173 STATIC_USERMODEHELPER_PATH to an empty string.
204 174
205 config STATIC_USERMODEHELPER_PATH 175 config STATIC_USERMODEHELPER_PATH
206 string "Path to the static usermode he 176 string "Path to the static usermode helper binary"
207 depends on STATIC_USERMODEHELPER 177 depends on STATIC_USERMODEHELPER
208 default "/sbin/usermode-helper" 178 default "/sbin/usermode-helper"
209 help 179 help
210 The binary called by the kernel when 180 The binary called by the kernel when any usermode helper
211 program is wish to be run. The "rea 181 program is wish to be run. The "real" application's name will
212 be in the first argument passed to t 182 be in the first argument passed to this program on the command
213 line. 183 line.
214 184
215 If you wish for all usermode helper 185 If you wish for all usermode helper programs to be disabled,
216 specify an empty string here (i.e. " 186 specify an empty string here (i.e. "").
217 187
218 source "security/selinux/Kconfig" 188 source "security/selinux/Kconfig"
219 source "security/smack/Kconfig" 189 source "security/smack/Kconfig"
220 source "security/tomoyo/Kconfig" 190 source "security/tomoyo/Kconfig"
221 source "security/apparmor/Kconfig" 191 source "security/apparmor/Kconfig"
222 source "security/loadpin/Kconfig" 192 source "security/loadpin/Kconfig"
223 source "security/yama/Kconfig" 193 source "security/yama/Kconfig"
224 source "security/safesetid/Kconfig" 194 source "security/safesetid/Kconfig"
225 source "security/lockdown/Kconfig" 195 source "security/lockdown/Kconfig"
226 source "security/landlock/Kconfig" 196 source "security/landlock/Kconfig"
227 197
228 source "security/integrity/Kconfig" 198 source "security/integrity/Kconfig"
229 199
230 choice 200 choice
231 prompt "First legacy 'major LSM' to be 201 prompt "First legacy 'major LSM' to be initialized"
232 default DEFAULT_SECURITY_SELINUX if SE 202 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
233 default DEFAULT_SECURITY_SMACK if SECU 203 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
234 default DEFAULT_SECURITY_TOMOYO if SEC 204 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
235 default DEFAULT_SECURITY_APPARMOR if S 205 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
236 default DEFAULT_SECURITY_DAC 206 default DEFAULT_SECURITY_DAC
237 207
238 help 208 help
239 This choice is there only for conver 209 This choice is there only for converting CONFIG_DEFAULT_SECURITY
240 in old kernel configs to CONFIG_LSM 210 in old kernel configs to CONFIG_LSM in new kernel configs. Don't
241 change this choice unless you are cr 211 change this choice unless you are creating a fresh kernel config,
242 for this choice will be ignored afte 212 for this choice will be ignored after CONFIG_LSM has been set.
243 213
244 Selects the legacy "major security m 214 Selects the legacy "major security module" that will be
245 initialized first. Overridden by non 215 initialized first. Overridden by non-default CONFIG_LSM.
246 216
247 config DEFAULT_SECURITY_SELINUX 217 config DEFAULT_SECURITY_SELINUX
248 bool "SELinux" if SECURITY_SEL 218 bool "SELinux" if SECURITY_SELINUX=y
249 219
250 config DEFAULT_SECURITY_SMACK 220 config DEFAULT_SECURITY_SMACK
251 bool "Simplified Mandatory Acc 221 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
252 222
253 config DEFAULT_SECURITY_TOMOYO 223 config DEFAULT_SECURITY_TOMOYO
254 bool "TOMOYO" if SECURITY_TOMO 224 bool "TOMOYO" if SECURITY_TOMOYO=y
255 225
256 config DEFAULT_SECURITY_APPARMOR 226 config DEFAULT_SECURITY_APPARMOR
257 bool "AppArmor" if SECURITY_AP 227 bool "AppArmor" if SECURITY_APPARMOR=y
258 228
259 config DEFAULT_SECURITY_DAC 229 config DEFAULT_SECURITY_DAC
260 bool "Unix Discretionary Acces 230 bool "Unix Discretionary Access Controls"
261 231
262 endchoice 232 endchoice
263 233
264 config LSM 234 config LSM
265 string "Ordered list of enabled LSMs" 235 string "Ordered list of enabled LSMs"
266 default "landlock,lockdown,yama,loadpi 236 default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
267 default "landlock,lockdown,yama,loadpi 237 default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
268 default "landlock,lockdown,yama,loadpi 238 default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
269 default "landlock,lockdown,yama,loadpi 239 default "landlock,lockdown,yama,loadpin,safesetid,bpf" if DEFAULT_SECURITY_DAC
270 default "landlock,lockdown,yama,loadpi 240 default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,bpf"
271 help 241 help
272 A comma-separated list of LSMs, in i 242 A comma-separated list of LSMs, in initialization order.
273 Any LSMs left off this list, except 243 Any LSMs left off this list, except for those with order
274 LSM_ORDER_FIRST and LSM_ORDER_LAST, 244 LSM_ORDER_FIRST and LSM_ORDER_LAST, which are always enabled
275 if selected in the kernel configurat 245 if selected in the kernel configuration, will be ignored.
276 This can be controlled at boot with 246 This can be controlled at boot with the "lsm=" parameter.
277 247
278 If unsure, leave this as the default 248 If unsure, leave this as the default.
279 249
280 source "security/Kconfig.hardening" 250 source "security/Kconfig.hardening"
281 251
282 source "security/ccsecurity/Kconfig" 252 source "security/ccsecurity/Kconfig"
283 253
284 endmenu 254 endmenu
285 255
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.