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 22choice 23 prompt "Allow /proc/pid/mem access override" 24 default PROC_MEM_FORCE_PTRACE 25 help 26 Traditionally /proc/pid/mem allows users to override memory 27 permissions for users like ptrace, assuming they have ptrace 28 capability. 29 30 This allows people to limit that - either never override, or 31 require actual active ptrace attachment (default). 32 33config PROC_MEM_ALWAYS_FORCE 34 bool "Traditional /proc/pid/mem behavior" 35 help 36 This allows /proc/pid/mem accesses to override memory mapping 37 permissions if you have ptrace access rights. 38 39config PROC_MEM_FORCE_PTRACE 40 bool "Require active ptrace() use for access override" 41 help 42 This allows /proc/pid/mem accesses to override memory mapping 43 permissions for active ptracers like gdb. 44 45config PROC_MEM_NO_FORCE 46 bool "Never" 47 help 48 Never override memory mapping permissions 49 50endchoice 51 52config MSEAL_SYSTEM_MAPPINGS 53 bool "mseal system mappings" 54 depends on 64BIT 55 depends on ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 56 depends on !CHECKPOINT_RESTORE 57 help 58 Apply mseal on system mappings. 59 The system mappings includes vdso, vvar, vvar_vclock, 60 vectors (arm compat-mode), sigpage (arm compat-mode), uprobes. 61 62 A 64-bit kernel is required for the memory sealing feature. 63 No specific hardware features from the CPU are needed. 64 65 WARNING: This feature breaks programs which rely on relocating 66 or unmapping system mappings. Known broken software at the time 67 of writing includes CHECKPOINT_RESTORE, UML, gVisor, rr. Therefore 68 this config can't be enabled universally. 69 70 For complete descriptions of memory sealing, please see 71 Documentation/userspace-api/mseal.rst 72 73config SECURITY 74 bool "Enable different security models" 75 depends on SYSFS 76 depends on MULTIUSER 77 help 78 This allows you to choose different security modules to be 79 configured into your kernel. 80 81 If this option is not selected, the default Linux security 82 model will be used. 83 84 If you are unsure how to answer this question, answer N. 85 86config HAS_SECURITY_AUDIT 87 def_bool y 88 depends on AUDIT 89 depends on SECURITY 90 91config SECURITYFS 92 bool "Enable the securityfs filesystem" 93 help 94 This will build the securityfs filesystem. It is currently used by 95 various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM). 96 97 If you are unsure how to answer this question, answer N. 98 99config SECURITY_NETWORK 100 bool "Socket and Networking Security Hooks" 101 depends on SECURITY 102 help 103 This enables the socket and networking security hooks. 104 If enabled, a security module can use these hooks to 105 implement socket and networking access controls. 106 If you are unsure how to answer this question, answer N. 107 108config SECURITY_INFINIBAND 109 bool "Infiniband Security Hooks" 110 depends on SECURITY && INFINIBAND 111 help 112 This enables the Infiniband security hooks. 113 If enabled, a security module can use these hooks to 114 implement Infiniband access controls. 115 If you are unsure how to answer this question, answer N. 116 117config SECURITY_NETWORK_XFRM 118 bool "XFRM (IPSec) Networking Security Hooks" 119 depends on XFRM && SECURITY_NETWORK 120 help 121 This enables the XFRM (IPSec) networking security hooks. 122 If enabled, a security module can use these hooks to 123 implement per-packet access controls based on labels 124 derived from IPSec policy. Non-IPSec communications are 125 designated as unlabelled, and only sockets authorized 126 to communicate unlabelled data can send without using 127 IPSec. 128 If you are unsure how to answer this question, answer N. 129 130config SECURITY_PATH 131 bool "Security hooks for pathname based access control" 132 depends on SECURITY 133 help 134 This enables the security hooks for pathname based access control. 135 If enabled, a security module can use these hooks to 136 implement pathname based access controls. 137 If you are unsure how to answer this question, answer N. 138 139config INTEL_TXT 140 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)" 141 depends on HAVE_INTEL_TXT 142 help 143 This option enables support for booting the kernel with the 144 Trusted Boot (tboot) module. This will utilize 145 Intel(R) Trusted Execution Technology to perform a measured launch 146 of the kernel. If the system does not support Intel(R) TXT, this 147 will have no effect. 148 149 Intel TXT will provide higher assurance of system configuration and 150 initial state as well as data reset protection. This is used to 151 create a robust initial kernel measurement and verification, which 152 helps to ensure that kernel security mechanisms are functioning 153 correctly. This level of protection requires a root of trust outside 154 of the kernel itself. 155 156 Intel TXT also helps solve real end user concerns about having 157 confidence that their hardware is running the VMM or kernel that 158 it was configured with, especially since they may be responsible for 159 providing such assurances to VMs and services running on it. 160 161 See <https://www.intel.com/technology/security/> for more information 162 about Intel(R) TXT. 163 See <http://tboot.sourceforge.net> for more information about tboot. 164 See Documentation/arch/x86/intel_txt.rst for a description of how to enable 165 Intel TXT support in a kernel boot. 166 167 If you are unsure as to whether this is required, answer N. 168 169config LSM_MMAP_MIN_ADDR 170 int "Low address space for LSM to protect from user allocation" 171 depends on SECURITY && SECURITY_SELINUX 172 default 32768 if ARM || (ARM64 && COMPAT) 173 default 65536 174 help 175 This is the portion of low virtual memory which should be protected 176 from userspace allocation. Keeping a user from writing to low pages 177 can help reduce the impact of kernel NULL pointer bugs. 178 179 For most ia64, ppc64 and x86 users with lots of address space 180 a value of 65536 is reasonable and should cause no problems. 181 On arm and other archs it should not be higher than 32768. 182 Programs which use vm86 functionality or have some need to map 183 this low address space will need the permission specific to the 184 systems running LSM. 185 186config STATIC_USERMODEHELPER 187 bool "Force all usermode helper calls through a single binary" 188 help 189 By default, the kernel can call many different userspace 190 binary programs through the "usermode helper" kernel 191 interface. Some of these binaries are statically defined 192 either in the kernel code itself, or as a kernel configuration 193 option. However, some of these are dynamically created at 194 runtime, or can be modified after the kernel has started up. 195 To provide an additional layer of security, route all of these 196 calls through a single executable that can not have its name 197 changed. 198 199 Note, it is up to this single binary to then call the relevant 200 "real" usermode helper binary, based on the first argument 201 passed to it. If desired, this program can filter and pick 202 and choose what real programs are called. 203 204 If you wish for all usermode helper programs are to be 205 disabled, choose this option and then set 206 STATIC_USERMODEHELPER_PATH to an empty string. 207 208config STATIC_USERMODEHELPER_PATH 209 string "Path to the static usermode helper binary" 210 depends on STATIC_USERMODEHELPER 211 default "/sbin/usermode-helper" 212 help 213 The binary called by the kernel when any usermode helper 214 program is wish to be run. The "real" application's name will 215 be in the first argument passed to this program on the command 216 line. 217 218 If you wish for all usermode helper programs to be disabled, 219 specify an empty string here (i.e. ""). 220 221source "security/selinux/Kconfig" 222source "security/smack/Kconfig" 223source "security/tomoyo/Kconfig" 224source "security/apparmor/Kconfig" 225source "security/loadpin/Kconfig" 226source "security/yama/Kconfig" 227source "security/safesetid/Kconfig" 228source "security/lockdown/Kconfig" 229source "security/landlock/Kconfig" 230source "security/ipe/Kconfig" 231 232source "security/integrity/Kconfig" 233 234choice 235 prompt "First legacy 'major LSM' to be initialized" 236 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX 237 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK 238 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO 239 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR 240 default DEFAULT_SECURITY_DAC 241 242 help 243 This choice is there only for converting CONFIG_DEFAULT_SECURITY 244 in old kernel configs to CONFIG_LSM in new kernel configs. Don't 245 change this choice unless you are creating a fresh kernel config, 246 for this choice will be ignored after CONFIG_LSM has been set. 247 248 Selects the legacy "major security module" that will be 249 initialized first. Overridden by non-default CONFIG_LSM. 250 251 config DEFAULT_SECURITY_SELINUX 252 bool "SELinux" if SECURITY_SELINUX=y 253 254 config DEFAULT_SECURITY_SMACK 255 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y 256 257 config DEFAULT_SECURITY_TOMOYO 258 bool "TOMOYO" if SECURITY_TOMOYO=y 259 260 config DEFAULT_SECURITY_APPARMOR 261 bool "AppArmor" if SECURITY_APPARMOR=y 262 263 config DEFAULT_SECURITY_DAC 264 bool "Unix Discretionary Access Controls" 265 266endchoice 267 268config LSM 269 string "Ordered list of enabled LSMs" 270 depends on SECURITY 271 default "landlock,lockdown,yama,loadpin,safesetid,smack,selinux,tomoyo,apparmor,ipe,bpf" if DEFAULT_SECURITY_SMACK 272 default "landlock,lockdown,yama,loadpin,safesetid,apparmor,selinux,smack,tomoyo,ipe,bpf" if DEFAULT_SECURITY_APPARMOR 273 default "landlock,lockdown,yama,loadpin,safesetid,tomoyo,ipe,bpf" if DEFAULT_SECURITY_TOMOYO 274 default "landlock,lockdown,yama,loadpin,safesetid,ipe,bpf" if DEFAULT_SECURITY_DAC 275 default "landlock,lockdown,yama,loadpin,safesetid,selinux,smack,tomoyo,apparmor,ipe,bpf" 276 help 277 A comma-separated list of LSMs, in initialization order. 278 Any LSMs left off this list, except for those with order 279 LSM_ORDER_FIRST and LSM_ORDER_LAST, which are always enabled 280 if selected in the kernel configuration, will be ignored. 281 This can be controlled at boot with the "lsm=" parameter. 282 283 If unsure, leave this as the default. 284 285config SECURITY_COMMONCAP_KUNIT_TEST 286 bool "Build KUnit tests for commoncap" if !KUNIT_ALL_TESTS 287 depends on KUNIT=y && USER_NS 288 default KUNIT_ALL_TESTS 289 help 290 This builds the commoncap KUnit tests. 291 292 KUnit tests run during boot and output the results to the debug log 293 in TAP format (https://testanything.org/). Only useful for kernel devs 294 running KUnit test harness and are not for inclusion into a 295 production build. 296 297 For more information on KUnit and unit tests in general please refer 298 to the KUnit documentation in Documentation/dev-tools/kunit/. 299 300 If unsure, say N. 301 302source "security/Kconfig.hardening" 303 304endmenu 305 306