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