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
>> 35 config SECURITY_WRITABLE_HOOKS
>> 36 depends on SECURITY
>> 37 bool
>> 38 default n
>> 39
67 config SECURITYFS 40 config SECURITYFS
68 bool "Enable the securityfs filesystem 41 bool "Enable the securityfs filesystem"
69 help 42 help
70 This will build the securityfs files 43 This will build the securityfs filesystem. It is currently used by
71 various security modules (AppArmor, 44 various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
72 45
73 If you are unsure how to answer this 46 If you are unsure how to answer this question, answer N.
74 47
75 config SECURITY_NETWORK 48 config SECURITY_NETWORK
76 bool "Socket and Networking Security H 49 bool "Socket and Networking Security Hooks"
77 depends on SECURITY 50 depends on SECURITY
78 help 51 help
79 This enables the socket and networki 52 This enables the socket and networking security hooks.
80 If enabled, a security module can us 53 If enabled, a security module can use these hooks to
81 implement socket and networking acce 54 implement socket and networking access controls.
82 If you are unsure how to answer this 55 If you are unsure how to answer this question, answer N.
83 56
>> 57 config PAGE_TABLE_ISOLATION
>> 58 bool "Remove the kernel mapping in user mode"
>> 59 default y
>> 60 depends on (X86_64 || X86_PAE) && !UML
>> 61 help
>> 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.
>> 65
>> 66 See Documentation/x86/pti.rst for more details.
>> 67
84 config SECURITY_INFINIBAND 68 config SECURITY_INFINIBAND
85 bool "Infiniband Security Hooks" 69 bool "Infiniband Security Hooks"
86 depends on SECURITY && INFINIBAND 70 depends on SECURITY && INFINIBAND
87 help 71 help
88 This enables the Infiniband security 72 This enables the Infiniband security hooks.
89 If enabled, a security module can us 73 If enabled, a security module can use these hooks to
90 implement Infiniband access controls 74 implement Infiniband access controls.
91 If you are unsure how to answer this 75 If you are unsure how to answer this question, answer N.
92 76
93 config SECURITY_NETWORK_XFRM 77 config SECURITY_NETWORK_XFRM
94 bool "XFRM (IPSec) Networking Security 78 bool "XFRM (IPSec) Networking Security Hooks"
95 depends on XFRM && SECURITY_NETWORK 79 depends on XFRM && SECURITY_NETWORK
96 help 80 help
97 This enables the XFRM (IPSec) networ 81 This enables the XFRM (IPSec) networking security hooks.
98 If enabled, a security module can us 82 If enabled, a security module can use these hooks to
99 implement per-packet access controls 83 implement per-packet access controls based on labels
100 derived from IPSec policy. Non-IPSe 84 derived from IPSec policy. Non-IPSec communications are
101 designated as unlabelled, and only s 85 designated as unlabelled, and only sockets authorized
102 to communicate unlabelled data can s 86 to communicate unlabelled data can send without using
103 IPSec. 87 IPSec.
104 If you are unsure how to answer this 88 If you are unsure how to answer this question, answer N.
105 89
106 config SECURITY_PATH 90 config SECURITY_PATH
107 bool "Security hooks for pathname base 91 bool "Security hooks for pathname based access control"
108 depends on SECURITY 92 depends on SECURITY
109 help 93 help
110 This enables the security hooks for 94 This enables the security hooks for pathname based access control.
111 If enabled, a security module can us 95 If enabled, a security module can use these hooks to
112 implement pathname based access cont 96 implement pathname based access controls.
113 If you are unsure how to answer this 97 If you are unsure how to answer this question, answer N.
114 98
115 config INTEL_TXT 99 config INTEL_TXT
116 bool "Enable Intel(R) Trusted Executio 100 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
117 depends on HAVE_INTEL_TXT 101 depends on HAVE_INTEL_TXT
118 help 102 help
119 This option enables support for boot 103 This option enables support for booting the kernel with the
120 Trusted Boot (tboot) module. This wi 104 Trusted Boot (tboot) module. This will utilize
121 Intel(R) Trusted Execution Technolog 105 Intel(R) Trusted Execution Technology to perform a measured launch
122 of the kernel. If the system does no 106 of the kernel. If the system does not support Intel(R) TXT, this
123 will have no effect. 107 will have no effect.
124 108
125 Intel TXT will provide higher assura 109 Intel TXT will provide higher assurance of system configuration and
126 initial state as well as data reset 110 initial state as well as data reset protection. This is used to
127 create a robust initial kernel measu 111 create a robust initial kernel measurement and verification, which
128 helps to ensure that kernel security 112 helps to ensure that kernel security mechanisms are functioning
129 correctly. This level of protection 113 correctly. This level of protection requires a root of trust outside
130 of the kernel itself. 114 of the kernel itself.
131 115
132 Intel TXT also helps solve real end 116 Intel TXT also helps solve real end user concerns about having
133 confidence that their hardware is ru 117 confidence that their hardware is running the VMM or kernel that
134 it was configured with, especially s 118 it was configured with, especially since they may be responsible for
135 providing such assurances to VMs and 119 providing such assurances to VMs and services running on it.
136 120
137 See <https://www.intel.com/technolog 121 See <https://www.intel.com/technology/security/> for more information
138 about Intel(R) TXT. 122 about Intel(R) TXT.
139 See <http://tboot.sourceforge.net> f 123 See <http://tboot.sourceforge.net> for more information about tboot.
140 See Documentation/arch/x86/intel_txt !! 124 See Documentation/x86/intel_txt.rst for a description of how to enable
141 Intel TXT support in a kernel boot. 125 Intel TXT support in a kernel boot.
142 126
143 If you are unsure as to whether this 127 If you are unsure as to whether this is required, answer N.
144 128
145 config LSM_MMAP_MIN_ADDR 129 config LSM_MMAP_MIN_ADDR
146 int "Low address space for LSM to prot 130 int "Low address space for LSM to protect from user allocation"
147 depends on SECURITY && SECURITY_SELINU 131 depends on SECURITY && SECURITY_SELINUX
148 default 32768 if ARM || (ARM64 && COMP 132 default 32768 if ARM || (ARM64 && COMPAT)
149 default 65536 133 default 65536
150 help 134 help
151 This is the portion of low virtual m 135 This is the portion of low virtual memory which should be protected
152 from userspace allocation. Keeping 136 from userspace allocation. Keeping a user from writing to low pages
153 can help reduce the impact of kernel 137 can help reduce the impact of kernel NULL pointer bugs.
154 138
155 For most ia64, ppc64 and x86 users w 139 For most ia64, ppc64 and x86 users with lots of address space
156 a value of 65536 is reasonable and s 140 a value of 65536 is reasonable and should cause no problems.
157 On arm and other archs it should not 141 On arm and other archs it should not be higher than 32768.
158 Programs which use vm86 functionalit 142 Programs which use vm86 functionality or have some need to map
159 this low address space will need the 143 this low address space will need the permission specific to the
160 systems running LSM. 144 systems running LSM.
161 145
>> 146 config HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 147 bool
>> 148 help
>> 149 The heap allocator implements __check_heap_object() for
>> 150 validating memory ranges against heap object sizes in
>> 151 support of CONFIG_HARDENED_USERCOPY.
>> 152
162 config HARDENED_USERCOPY 153 config HARDENED_USERCOPY
163 bool "Harden memory copies between ker 154 bool "Harden memory copies between kernel and userspace"
>> 155 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
164 imply STRICT_DEVMEM 156 imply STRICT_DEVMEM
165 help 157 help
166 This option checks for obviously wro 158 This option checks for obviously wrong memory regions when
167 copying memory to/from the kernel (v 159 copying memory to/from the kernel (via copy_to_user() and
168 copy_from_user() functions) by rejec 160 copy_from_user() functions) by rejecting memory ranges that
169 are larger than the specified heap o 161 are larger than the specified heap object, span multiple
170 separately allocated pages, are not 162 separately allocated pages, are not on the process stack,
171 or are part of the kernel text. This !! 163 or are part of the kernel text. This kills entire classes
172 of heap overflow exploits and simila 164 of heap overflow exploits and similar kernel memory exposures.
173 165
>> 166 config HARDENED_USERCOPY_FALLBACK
>> 167 bool "Allow usercopy whitelist violations to fallback to object size"
>> 168 depends on HARDENED_USERCOPY
>> 169 default y
>> 170 help
>> 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.
>> 179
>> 180 config HARDENED_USERCOPY_PAGESPAN
>> 181 bool "Refuse to copy allocations that span multiple pages"
>> 182 depends on HARDENED_USERCOPY
>> 183 depends on EXPERT
>> 184 help
>> 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.
>> 190
174 config FORTIFY_SOURCE 191 config FORTIFY_SOURCE
175 bool "Harden common str/mem functions 192 bool "Harden common str/mem functions against buffer overflows"
176 depends on ARCH_HAS_FORTIFY_SOURCE 193 depends on ARCH_HAS_FORTIFY_SOURCE
177 # https://github.com/llvm/llvm-project <<
178 depends on !CC_IS_CLANG || !X86_32 <<
179 help 194 help
180 Detect overflows of buffers in commo 195 Detect overflows of buffers in common string and memory functions
181 where the compiler can determine and 196 where the compiler can determine and validate the buffer sizes.
182 197
183 config STATIC_USERMODEHELPER 198 config STATIC_USERMODEHELPER
184 bool "Force all usermode helper calls 199 bool "Force all usermode helper calls through a single binary"
185 help 200 help
186 By default, the kernel can call many 201 By default, the kernel can call many different userspace
187 binary programs through the "usermod 202 binary programs through the "usermode helper" kernel
188 interface. Some of these binaries a 203 interface. Some of these binaries are statically defined
189 either in the kernel code itself, or 204 either in the kernel code itself, or as a kernel configuration
190 option. However, some of these are 205 option. However, some of these are dynamically created at
191 runtime, or can be modified after th 206 runtime, or can be modified after the kernel has started up.
192 To provide an additional layer of se 207 To provide an additional layer of security, route all of these
193 calls through a single executable th 208 calls through a single executable that can not have its name
194 changed. 209 changed.
195 210
196 Note, it is up to this single binary 211 Note, it is up to this single binary to then call the relevant
197 "real" usermode helper binary, based 212 "real" usermode helper binary, based on the first argument
198 passed to it. If desired, this prog 213 passed to it. If desired, this program can filter and pick
199 and choose what real programs are ca 214 and choose what real programs are called.
200 215
201 If you wish for all usermode helper 216 If you wish for all usermode helper programs are to be
202 disabled, choose this option and the 217 disabled, choose this option and then set
203 STATIC_USERMODEHELPER_PATH to an emp 218 STATIC_USERMODEHELPER_PATH to an empty string.
204 219
205 config STATIC_USERMODEHELPER_PATH 220 config STATIC_USERMODEHELPER_PATH
206 string "Path to the static usermode he 221 string "Path to the static usermode helper binary"
207 depends on STATIC_USERMODEHELPER 222 depends on STATIC_USERMODEHELPER
208 default "/sbin/usermode-helper" 223 default "/sbin/usermode-helper"
209 help 224 help
210 The binary called by the kernel when 225 The binary called by the kernel when any usermode helper
211 program is wish to be run. The "rea 226 program is wish to be run. The "real" application's name will
212 be in the first argument passed to t 227 be in the first argument passed to this program on the command
213 line. 228 line.
214 229
215 If you wish for all usermode helper 230 If you wish for all usermode helper programs to be disabled,
216 specify an empty string here (i.e. " 231 specify an empty string here (i.e. "").
217 232
218 source "security/selinux/Kconfig" 233 source "security/selinux/Kconfig"
219 source "security/smack/Kconfig" 234 source "security/smack/Kconfig"
220 source "security/tomoyo/Kconfig" 235 source "security/tomoyo/Kconfig"
221 source "security/apparmor/Kconfig" 236 source "security/apparmor/Kconfig"
222 source "security/loadpin/Kconfig" 237 source "security/loadpin/Kconfig"
223 source "security/yama/Kconfig" 238 source "security/yama/Kconfig"
224 source "security/safesetid/Kconfig" 239 source "security/safesetid/Kconfig"
225 source "security/lockdown/Kconfig" 240 source "security/lockdown/Kconfig"
226 source "security/landlock/Kconfig" <<
227 241
228 source "security/integrity/Kconfig" 242 source "security/integrity/Kconfig"
229 243
230 choice 244 choice
231 prompt "First legacy 'major LSM' to be 245 prompt "First legacy 'major LSM' to be initialized"
232 default DEFAULT_SECURITY_SELINUX if SE 246 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
233 default DEFAULT_SECURITY_SMACK if SECU 247 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
234 default DEFAULT_SECURITY_TOMOYO if SEC 248 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
235 default DEFAULT_SECURITY_APPARMOR if S 249 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
236 default DEFAULT_SECURITY_DAC 250 default DEFAULT_SECURITY_DAC
237 251
238 help 252 help
239 This choice is there only for conver 253 This choice is there only for converting CONFIG_DEFAULT_SECURITY
240 in old kernel configs to CONFIG_LSM 254 in old kernel configs to CONFIG_LSM in new kernel configs. Don't
241 change this choice unless you are cr 255 change this choice unless you are creating a fresh kernel config,
242 for this choice will be ignored afte 256 for this choice will be ignored after CONFIG_LSM has been set.
243 257
244 Selects the legacy "major security m 258 Selects the legacy "major security module" that will be
245 initialized first. Overridden by non 259 initialized first. Overridden by non-default CONFIG_LSM.
246 260
247 config DEFAULT_SECURITY_SELINUX 261 config DEFAULT_SECURITY_SELINUX
248 bool "SELinux" if SECURITY_SEL 262 bool "SELinux" if SECURITY_SELINUX=y
249 263
250 config DEFAULT_SECURITY_SMACK 264 config DEFAULT_SECURITY_SMACK
251 bool "Simplified Mandatory Acc 265 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
252 266
253 config DEFAULT_SECURITY_TOMOYO 267 config DEFAULT_SECURITY_TOMOYO
254 bool "TOMOYO" if SECURITY_TOMO 268 bool "TOMOYO" if SECURITY_TOMOYO=y
255 269
256 config DEFAULT_SECURITY_APPARMOR 270 config DEFAULT_SECURITY_APPARMOR
257 bool "AppArmor" if SECURITY_AP 271 bool "AppArmor" if SECURITY_APPARMOR=y
258 272
259 config DEFAULT_SECURITY_DAC 273 config DEFAULT_SECURITY_DAC
260 bool "Unix Discretionary Acces 274 bool "Unix Discretionary Access Controls"
261 275
262 endchoice 276 endchoice
263 277
264 config LSM 278 config LSM
265 string "Ordered list of enabled LSMs" 279 string "Ordered list of enabled LSMs"
266 default "landlock,lockdown,yama,loadpi !! 280 default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK
267 default "landlock,lockdown,yama,loadpi !! 281 default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR
268 default "landlock,lockdown,yama,loadpi !! 282 default "lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO
269 default "landlock,lockdown,yama,loadpi !! 283 default "lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC
270 default "landlock,lockdown,yama,loadpi !! 284 default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf"
271 help 285 help
272 A comma-separated list of LSMs, in i 286 A comma-separated list of LSMs, in initialization order.
273 Any LSMs left off this list, except !! 287 Any LSMs left off this list will be ignored. This can be
274 LSM_ORDER_FIRST and LSM_ORDER_LAST, !! 288 controlled at boot with the "lsm=" parameter.
275 if selected in the kernel configurat <<
276 This can be controlled at boot with <<
277 289
278 If unsure, leave this as the default 290 If unsure, leave this as the default.
279 291
280 source "security/Kconfig.hardening" 292 source "security/Kconfig.hardening"
281 293
282 source "security/ccsecurity/Kconfig" 294 source "security/ccsecurity/Kconfig"
283 295
284 endmenu 296 endmenu
285 297
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.