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