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 22 choice
23 prompt "Allow /proc/pid/mem access ove 23 prompt "Allow /proc/pid/mem access override"
24 default PROC_MEM_ALWAYS_FORCE 24 default PROC_MEM_ALWAYS_FORCE
25 help 25 help
26 Traditionally /proc/pid/mem allows u 26 Traditionally /proc/pid/mem allows users to override memory
27 permissions for users like ptrace, a 27 permissions for users like ptrace, assuming they have ptrace
28 capability. 28 capability.
29 29
30 This allows people to limit that - e 30 This allows people to limit that - either never override, or
31 require actual active ptrace attachm 31 require actual active ptrace attachment.
32 32
33 Defaults to the traditional behavior 33 Defaults to the traditional behavior (for now)
34 34
35 config PROC_MEM_ALWAYS_FORCE 35 config PROC_MEM_ALWAYS_FORCE
36 bool "Traditional /proc/pid/mem behavi 36 bool "Traditional /proc/pid/mem behavior"
37 help 37 help
38 This allows /proc/pid/mem accesses t 38 This allows /proc/pid/mem accesses to override memory mapping
39 permissions if you have ptrace acces 39 permissions if you have ptrace access rights.
40 40
41 config PROC_MEM_FORCE_PTRACE 41 config PROC_MEM_FORCE_PTRACE
42 bool "Require active ptrace() use for 42 bool "Require active ptrace() use for access override"
43 help 43 help
44 This allows /proc/pid/mem accesses t 44 This allows /proc/pid/mem accesses to override memory mapping
45 permissions for active ptracers like 45 permissions for active ptracers like gdb.
46 46
47 config PROC_MEM_NO_FORCE 47 config PROC_MEM_NO_FORCE
48 bool "Never" 48 bool "Never"
49 help 49 help
50 Never override memory mapping permis 50 Never override memory mapping permissions
51 51
52 endchoice 52 endchoice
53 53
54 config SECURITY 54 config SECURITY
55 bool "Enable different security models 55 bool "Enable different security models"
56 depends on SYSFS 56 depends on SYSFS
57 depends on MULTIUSER 57 depends on MULTIUSER
58 help 58 help
59 This allows you to choose different 59 This allows you to choose different security modules to be
60 configured into your kernel. 60 configured into your kernel.
61 61
62 If this option is not selected, the 62 If this option is not selected, the default Linux security
63 model will be used. 63 model will be used.
64 64
65 If you are unsure how to answer this 65 If you are unsure how to answer this question, answer N.
66 66
>> 67 config SECURITY_WRITABLE_HOOKS
>> 68 depends on SECURITY
>> 69 bool
>> 70 default n
>> 71
67 config SECURITYFS 72 config SECURITYFS
68 bool "Enable the securityfs filesystem 73 bool "Enable the securityfs filesystem"
69 help 74 help
70 This will build the securityfs files 75 This will build the securityfs filesystem. It is currently used by
71 various security modules (AppArmor, 76 various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM).
72 77
73 If you are unsure how to answer this 78 If you are unsure how to answer this question, answer N.
74 79
75 config SECURITY_NETWORK 80 config SECURITY_NETWORK
76 bool "Socket and Networking Security H 81 bool "Socket and Networking Security Hooks"
77 depends on SECURITY 82 depends on SECURITY
78 help 83 help
79 This enables the socket and networki 84 This enables the socket and networking security hooks.
80 If enabled, a security module can us 85 If enabled, a security module can use these hooks to
81 implement socket and networking acce 86 implement socket and networking access controls.
82 If you are unsure how to answer this 87 If you are unsure how to answer this question, answer N.
83 88
>> 89 config PAGE_TABLE_ISOLATION
>> 90 bool "Remove the kernel mapping in user mode"
>> 91 default y
>> 92 depends on (X86_64 || X86_PAE) && !UML
>> 93 help
>> 94 This feature reduces the number of hardware side channels by
>> 95 ensuring that the majority of kernel addresses are not mapped
>> 96 into userspace.
>> 97
>> 98 See Documentation/x86/pti.rst for more details.
>> 99
84 config SECURITY_INFINIBAND 100 config SECURITY_INFINIBAND
85 bool "Infiniband Security Hooks" 101 bool "Infiniband Security Hooks"
86 depends on SECURITY && INFINIBAND 102 depends on SECURITY && INFINIBAND
87 help 103 help
88 This enables the Infiniband security 104 This enables the Infiniband security hooks.
89 If enabled, a security module can us 105 If enabled, a security module can use these hooks to
90 implement Infiniband access controls 106 implement Infiniband access controls.
91 If you are unsure how to answer this 107 If you are unsure how to answer this question, answer N.
92 108
93 config SECURITY_NETWORK_XFRM 109 config SECURITY_NETWORK_XFRM
94 bool "XFRM (IPSec) Networking Security 110 bool "XFRM (IPSec) Networking Security Hooks"
95 depends on XFRM && SECURITY_NETWORK 111 depends on XFRM && SECURITY_NETWORK
96 help 112 help
97 This enables the XFRM (IPSec) networ 113 This enables the XFRM (IPSec) networking security hooks.
98 If enabled, a security module can us 114 If enabled, a security module can use these hooks to
99 implement per-packet access controls 115 implement per-packet access controls based on labels
100 derived from IPSec policy. Non-IPSe 116 derived from IPSec policy. Non-IPSec communications are
101 designated as unlabelled, and only s 117 designated as unlabelled, and only sockets authorized
102 to communicate unlabelled data can s 118 to communicate unlabelled data can send without using
103 IPSec. 119 IPSec.
104 If you are unsure how to answer this 120 If you are unsure how to answer this question, answer N.
105 121
106 config SECURITY_PATH 122 config SECURITY_PATH
107 bool "Security hooks for pathname base 123 bool "Security hooks for pathname based access control"
108 depends on SECURITY 124 depends on SECURITY
109 help 125 help
110 This enables the security hooks for 126 This enables the security hooks for pathname based access control.
111 If enabled, a security module can us 127 If enabled, a security module can use these hooks to
112 implement pathname based access cont 128 implement pathname based access controls.
113 If you are unsure how to answer this 129 If you are unsure how to answer this question, answer N.
114 130
115 config INTEL_TXT 131 config INTEL_TXT
116 bool "Enable Intel(R) Trusted Executio 132 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
117 depends on HAVE_INTEL_TXT 133 depends on HAVE_INTEL_TXT
118 help 134 help
119 This option enables support for boot 135 This option enables support for booting the kernel with the
120 Trusted Boot (tboot) module. This wi 136 Trusted Boot (tboot) module. This will utilize
121 Intel(R) Trusted Execution Technolog 137 Intel(R) Trusted Execution Technology to perform a measured launch
122 of the kernel. If the system does no 138 of the kernel. If the system does not support Intel(R) TXT, this
123 will have no effect. 139 will have no effect.
124 140
125 Intel TXT will provide higher assura 141 Intel TXT will provide higher assurance of system configuration and
126 initial state as well as data reset 142 initial state as well as data reset protection. This is used to
127 create a robust initial kernel measu 143 create a robust initial kernel measurement and verification, which
128 helps to ensure that kernel security 144 helps to ensure that kernel security mechanisms are functioning
129 correctly. This level of protection 145 correctly. This level of protection requires a root of trust outside
130 of the kernel itself. 146 of the kernel itself.
131 147
132 Intel TXT also helps solve real end 148 Intel TXT also helps solve real end user concerns about having
133 confidence that their hardware is ru 149 confidence that their hardware is running the VMM or kernel that
134 it was configured with, especially s 150 it was configured with, especially since they may be responsible for
135 providing such assurances to VMs and 151 providing such assurances to VMs and services running on it.
136 152
137 See <https://www.intel.com/technolog !! 153 See <http://www.intel.com/technology/security/> for more information
138 about Intel(R) TXT. 154 about Intel(R) TXT.
139 See <http://tboot.sourceforge.net> f 155 See <http://tboot.sourceforge.net> for more information about tboot.
140 See Documentation/arch/x86/intel_txt !! 156 See Documentation/x86/intel_txt.rst for a description of how to enable
141 Intel TXT support in a kernel boot. 157 Intel TXT support in a kernel boot.
142 158
143 If you are unsure as to whether this 159 If you are unsure as to whether this is required, answer N.
144 160
145 config LSM_MMAP_MIN_ADDR 161 config LSM_MMAP_MIN_ADDR
146 int "Low address space for LSM to prot 162 int "Low address space for LSM to protect from user allocation"
147 depends on SECURITY && SECURITY_SELINU 163 depends on SECURITY && SECURITY_SELINUX
148 default 32768 if ARM || (ARM64 && COMP 164 default 32768 if ARM || (ARM64 && COMPAT)
149 default 65536 165 default 65536
150 help 166 help
151 This is the portion of low virtual m 167 This is the portion of low virtual memory which should be protected
152 from userspace allocation. Keeping 168 from userspace allocation. Keeping a user from writing to low pages
153 can help reduce the impact of kernel 169 can help reduce the impact of kernel NULL pointer bugs.
154 170
155 For most ia64, ppc64 and x86 users w 171 For most ia64, ppc64 and x86 users with lots of address space
156 a value of 65536 is reasonable and s 172 a value of 65536 is reasonable and should cause no problems.
157 On arm and other archs it should not 173 On arm and other archs it should not be higher than 32768.
158 Programs which use vm86 functionalit 174 Programs which use vm86 functionality or have some need to map
159 this low address space will need the 175 this low address space will need the permission specific to the
160 systems running LSM. 176 systems running LSM.
161 177
>> 178 config HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 179 bool
>> 180 help
>> 181 The heap allocator implements __check_heap_object() for
>> 182 validating memory ranges against heap object sizes in
>> 183 support of CONFIG_HARDENED_USERCOPY.
>> 184
162 config HARDENED_USERCOPY 185 config HARDENED_USERCOPY
163 bool "Harden memory copies between ker 186 bool "Harden memory copies between kernel and userspace"
>> 187 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
164 imply STRICT_DEVMEM 188 imply STRICT_DEVMEM
165 help 189 help
166 This option checks for obviously wro 190 This option checks for obviously wrong memory regions when
167 copying memory to/from the kernel (v 191 copying memory to/from the kernel (via copy_to_user() and
168 copy_from_user() functions) by rejec 192 copy_from_user() functions) by rejecting memory ranges that
169 are larger than the specified heap o 193 are larger than the specified heap object, span multiple
170 separately allocated pages, are not 194 separately allocated pages, are not on the process stack,
171 or are part of the kernel text. This !! 195 or are part of the kernel text. This kills entire classes
172 of heap overflow exploits and simila 196 of heap overflow exploits and similar kernel memory exposures.
173 197
>> 198 config HARDENED_USERCOPY_FALLBACK
>> 199 bool "Allow usercopy whitelist violations to fallback to object size"
>> 200 depends on HARDENED_USERCOPY
>> 201 default y
>> 202 help
>> 203 This is a temporary option that allows missing usercopy whitelists
>> 204 to be discovered via a WARN() to the kernel log, instead of
>> 205 rejecting the copy, falling back to non-whitelisted hardened
>> 206 usercopy that checks the slab allocation size instead of the
>> 207 whitelist size. This option will be removed once it seems like
>> 208 all missing usercopy whitelists have been identified and fixed.
>> 209 Booting with "slab_common.usercopy_fallback=Y/N" can change
>> 210 this setting.
>> 211
>> 212 config HARDENED_USERCOPY_PAGESPAN
>> 213 bool "Refuse to copy allocations that span multiple pages"
>> 214 depends on HARDENED_USERCOPY
>> 215 depends on EXPERT
>> 216 help
>> 217 When a multi-page allocation is done without __GFP_COMP,
>> 218 hardened usercopy will reject attempts to copy it. There are,
>> 219 however, several cases of this in the kernel that have not all
>> 220 been removed. This config is intended to be used only while
>> 221 trying to find such users.
>> 222
174 config FORTIFY_SOURCE 223 config FORTIFY_SOURCE
175 bool "Harden common str/mem functions 224 bool "Harden common str/mem functions against buffer overflows"
176 depends on ARCH_HAS_FORTIFY_SOURCE 225 depends on ARCH_HAS_FORTIFY_SOURCE
177 # https://github.com/llvm/llvm-project !! 226 # https://bugs.llvm.org/show_bug.cgi?id=50322
178 depends on !CC_IS_CLANG || !X86_32 !! 227 # https://bugs.llvm.org/show_bug.cgi?id=41459
>> 228 depends on !CC_IS_CLANG
179 help 229 help
180 Detect overflows of buffers in commo 230 Detect overflows of buffers in common string and memory functions
181 where the compiler can determine and 231 where the compiler can determine and validate the buffer sizes.
182 232
183 config STATIC_USERMODEHELPER 233 config STATIC_USERMODEHELPER
184 bool "Force all usermode helper calls 234 bool "Force all usermode helper calls through a single binary"
185 help 235 help
186 By default, the kernel can call many 236 By default, the kernel can call many different userspace
187 binary programs through the "usermod 237 binary programs through the "usermode helper" kernel
188 interface. Some of these binaries a 238 interface. Some of these binaries are statically defined
189 either in the kernel code itself, or 239 either in the kernel code itself, or as a kernel configuration
190 option. However, some of these are 240 option. However, some of these are dynamically created at
191 runtime, or can be modified after th 241 runtime, or can be modified after the kernel has started up.
192 To provide an additional layer of se 242 To provide an additional layer of security, route all of these
193 calls through a single executable th 243 calls through a single executable that can not have its name
194 changed. 244 changed.
195 245
196 Note, it is up to this single binary 246 Note, it is up to this single binary to then call the relevant
197 "real" usermode helper binary, based 247 "real" usermode helper binary, based on the first argument
198 passed to it. If desired, this prog 248 passed to it. If desired, this program can filter and pick
199 and choose what real programs are ca 249 and choose what real programs are called.
200 250
201 If you wish for all usermode helper 251 If you wish for all usermode helper programs are to be
202 disabled, choose this option and the 252 disabled, choose this option and then set
203 STATIC_USERMODEHELPER_PATH to an emp 253 STATIC_USERMODEHELPER_PATH to an empty string.
204 254
205 config STATIC_USERMODEHELPER_PATH 255 config STATIC_USERMODEHELPER_PATH
206 string "Path to the static usermode he 256 string "Path to the static usermode helper binary"
207 depends on STATIC_USERMODEHELPER 257 depends on STATIC_USERMODEHELPER
208 default "/sbin/usermode-helper" 258 default "/sbin/usermode-helper"
209 help 259 help
210 The binary called by the kernel when 260 The binary called by the kernel when any usermode helper
211 program is wish to be run. The "rea 261 program is wish to be run. The "real" application's name will
212 be in the first argument passed to t 262 be in the first argument passed to this program on the command
213 line. 263 line.
214 264
215 If you wish for all usermode helper 265 If you wish for all usermode helper programs to be disabled,
216 specify an empty string here (i.e. " 266 specify an empty string here (i.e. "").
217 267
218 source "security/selinux/Kconfig" 268 source "security/selinux/Kconfig"
219 source "security/smack/Kconfig" 269 source "security/smack/Kconfig"
220 source "security/tomoyo/Kconfig" 270 source "security/tomoyo/Kconfig"
221 source "security/apparmor/Kconfig" 271 source "security/apparmor/Kconfig"
222 source "security/loadpin/Kconfig" 272 source "security/loadpin/Kconfig"
223 source "security/yama/Kconfig" 273 source "security/yama/Kconfig"
224 source "security/safesetid/Kconfig" 274 source "security/safesetid/Kconfig"
225 source "security/lockdown/Kconfig" 275 source "security/lockdown/Kconfig"
226 source "security/landlock/Kconfig" <<
227 source "security/ipe/Kconfig" <<
228 276
229 source "security/integrity/Kconfig" 277 source "security/integrity/Kconfig"
230 278
231 choice 279 choice
232 prompt "First legacy 'major LSM' to be 280 prompt "First legacy 'major LSM' to be initialized"
233 default DEFAULT_SECURITY_SELINUX if SE 281 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
234 default DEFAULT_SECURITY_SMACK if SECU 282 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
235 default DEFAULT_SECURITY_TOMOYO if SEC 283 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
236 default DEFAULT_SECURITY_APPARMOR if S 284 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
237 default DEFAULT_SECURITY_DAC 285 default DEFAULT_SECURITY_DAC
238 286
239 help 287 help
240 This choice is there only for conver 288 This choice is there only for converting CONFIG_DEFAULT_SECURITY
241 in old kernel configs to CONFIG_LSM 289 in old kernel configs to CONFIG_LSM in new kernel configs. Don't
242 change this choice unless you are cr 290 change this choice unless you are creating a fresh kernel config,
243 for this choice will be ignored afte 291 for this choice will be ignored after CONFIG_LSM has been set.
244 292
245 Selects the legacy "major security m 293 Selects the legacy "major security module" that will be
246 initialized first. Overridden by non 294 initialized first. Overridden by non-default CONFIG_LSM.
247 295
248 config DEFAULT_SECURITY_SELINUX 296 config DEFAULT_SECURITY_SELINUX
249 bool "SELinux" if SECURITY_SEL 297 bool "SELinux" if SECURITY_SELINUX=y
250 298
251 config DEFAULT_SECURITY_SMACK 299 config DEFAULT_SECURITY_SMACK
252 bool "Simplified Mandatory Acc 300 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
253 301
254 config DEFAULT_SECURITY_TOMOYO 302 config DEFAULT_SECURITY_TOMOYO
255 bool "TOMOYO" if SECURITY_TOMO 303 bool "TOMOYO" if SECURITY_TOMOYO=y
256 304
257 config DEFAULT_SECURITY_APPARMOR 305 config DEFAULT_SECURITY_APPARMOR
258 bool "AppArmor" if SECURITY_AP 306 bool "AppArmor" if SECURITY_APPARMOR=y
259 307
260 config DEFAULT_SECURITY_DAC 308 config DEFAULT_SECURITY_DAC
261 bool "Unix Discretionary Acces 309 bool "Unix Discretionary Access Controls"
262 310
263 endchoice 311 endchoice
264 312
265 config LSM 313 config LSM
266 string "Ordered list of enabled LSMs" 314 string "Ordered list of enabled LSMs"
267 default "landlock,lockdown,yama,loadpi !! 315 default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor" if DEFAULT_SECURITY_SMACK
268 default "landlock,lockdown,yama,loadpi !! 316 default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo" if DEFAULT_SECURITY_APPARMOR
269 default "landlock,lockdown,yama,loadpi !! 317 default "lockdown,yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO
270 default "landlock,lockdown,yama,loadpi !! 318 default "lockdown,yama,loadpin,safesetid,integrity" if DEFAULT_SECURITY_DAC
271 default "landlock,lockdown,yama,loadpi !! 319 default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"
272 help 320 help
273 A comma-separated list of LSMs, in i 321 A comma-separated list of LSMs, in initialization order.
274 Any LSMs left off this list, except !! 322 Any LSMs left off this list will be ignored. This can be
275 LSM_ORDER_FIRST and LSM_ORDER_LAST, !! 323 controlled at boot with the "lsm=" parameter.
276 if selected in the kernel configurat <<
277 This can be controlled at boot with <<
278 324
279 If unsure, leave this as the default 325 If unsure, leave this as the default.
280 326
281 source "security/Kconfig.hardening" 327 source "security/Kconfig.hardening"
282 328
283 source "security/ccsecurity/Kconfig" 329 source "security/ccsecurity/Kconfig"
284 330
285 endmenu 331 endmenu
286 332
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