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 22config SECURITY 23 bool "Enable different security models" 24 depends on SYSFS 25 depends on MULTIUSER 26 help 27 This allows you to choose different security modules to be 28 configured into your kernel. 29 30 If this option is not selected, the default Linux security 31 model will be used. 32 33 If you are unsure how to answer this question, answer N. 34 35config SECURITY_WRITABLE_HOOKS 36 depends on SECURITY 37 bool 38 default n 39 40config SECURITYFS 41 bool "Enable the securityfs filesystem" 42 help 43 This will build the securityfs filesystem. It is currently used by 44 various security modules (AppArmor, IMA, SafeSetID, TOMOYO, TPM). 45 46 If you are unsure how to answer this question, answer N. 47 48config SECURITY_NETWORK 49 bool "Socket and Networking Security Hooks" 50 depends on SECURITY 51 help 52 This enables the socket and networking security hooks. 53 If enabled, a security module can use these hooks to 54 implement socket and networking access controls. 55 If you are unsure how to answer this question, answer N. 56 57config SECURITY_INFINIBAND 58 bool "Infiniband Security Hooks" 59 depends on SECURITY && INFINIBAND 60 help 61 This enables the Infiniband security hooks. 62 If enabled, a security module can use these hooks to 63 implement Infiniband access controls. 64 If you are unsure how to answer this question, answer N. 65 66config SECURITY_NETWORK_XFRM 67 bool "XFRM (IPSec) Networking Security Hooks" 68 depends on XFRM && SECURITY_NETWORK 69 help 70 This enables the XFRM (IPSec) networking security hooks. 71 If enabled, a security module can use these hooks to 72 implement per-packet access controls based on labels 73 derived from IPSec policy. Non-IPSec communications are 74 designated as unlabelled, and only sockets authorized 75 to communicate unlabelled data can send without using 76 IPSec. 77 If you are unsure how to answer this question, answer N. 78 79config SECURITY_PATH 80 bool "Security hooks for pathname based access control" 81 depends on SECURITY 82 help 83 This enables the security hooks for pathname based access control. 84 If enabled, a security module can use these hooks to 85 implement pathname based access controls. 86 If you are unsure how to answer this question, answer N. 87 88config INTEL_TXT 89 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)" 90 depends on HAVE_INTEL_TXT 91 help 92 This option enables support for booting the kernel with the 93 Trusted Boot (tboot) module. This will utilize 94 Intel(R) Trusted Execution Technology to perform a measured launch 95 of the kernel. If the system does not support Intel(R) TXT, this 96 will have no effect. 97 98 Intel TXT will provide higher assurance of system configuration and 99 initial state as well as data reset protection. This is used to 100 create a robust initial kernel measurement and verification, which 101 helps to ensure that kernel security mechanisms are functioning 102 correctly. This level of protection requires a root of trust outside 103 of the kernel itself. 104 105 Intel TXT also helps solve real end user concerns about having 106 confidence that their hardware is running the VMM or kernel that 107 it was configured with, especially since they may be responsible for 108 providing such assurances to VMs and services running on it. 109 110 See <https://www.intel.com/technology/security/> for more information 111 about Intel(R) TXT. 112 See <http://tboot.sourceforge.net> for more information about tboot. 113 See Documentation/x86/intel_txt.rst for a description of how to enable 114 Intel TXT support in a kernel boot. 115 116 If you are unsure as to whether this is required, answer N. 117 118config LSM_MMAP_MIN_ADDR 119 int "Low address space for LSM to protect from user allocation" 120 depends on SECURITY && SECURITY_SELINUX 121 default 32768 if ARM || (ARM64 && COMPAT) 122 default 65536 123 help 124 This is the portion of low virtual memory which should be protected 125 from userspace allocation. Keeping a user from writing to low pages 126 can help reduce the impact of kernel NULL pointer bugs. 127 128 For most ia64, ppc64 and x86 users with lots of address space 129 a value of 65536 is reasonable and should cause no problems. 130 On arm and other archs it should not be higher than 32768. 131 Programs which use vm86 functionality or have some need to map 132 this low address space will need the permission specific to the 133 systems running LSM. 134 135config HAVE_HARDENED_USERCOPY_ALLOCATOR 136 bool 137 help 138 The heap allocator implements __check_heap_object() for 139 validating memory ranges against heap object sizes in 140 support of CONFIG_HARDENED_USERCOPY. 141 142config HARDENED_USERCOPY 143 bool "Harden memory copies between kernel and userspace" 144 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR 145 imply STRICT_DEVMEM 146 help 147 This option checks for obviously wrong memory regions when 148 copying memory to/from the kernel (via copy_to_user() and 149 copy_from_user() functions) by rejecting memory ranges that 150 are larger than the specified heap object, span multiple 151 separately allocated pages, are not on the process stack, 152 or are part of the kernel text. This prevents entire classes 153 of heap overflow exploits and similar kernel memory exposures. 154 155config FORTIFY_SOURCE 156 bool "Harden common str/mem functions against buffer overflows" 157 depends on ARCH_HAS_FORTIFY_SOURCE 158 # https://bugs.llvm.org/show_bug.cgi?id=41459 159 depends on !CC_IS_CLANG || CLANG_VERSION >= 120001 160 # https://github.com/llvm/llvm-project/issues/53645 161 depends on !CC_IS_CLANG || !X86_32 162 help 163 Detect overflows of buffers in common string and memory functions 164 where the compiler can determine and validate the buffer sizes. 165 166config STATIC_USERMODEHELPER 167 bool "Force all usermode helper calls through a single binary" 168 help 169 By default, the kernel can call many different userspace 170 binary programs through the "usermode helper" kernel 171 interface. Some of these binaries are statically defined 172 either in the kernel code itself, or as a kernel configuration 173 option. However, some of these are dynamically created at 174 runtime, or can be modified after the kernel has started up. 175 To provide an additional layer of security, route all of these 176 calls through a single executable that can not have its name 177 changed. 178 179 Note, it is up to this single binary to then call the relevant 180 "real" usermode helper binary, based on the first argument 181 passed to it. If desired, this program can filter and pick 182 and choose what real programs are called. 183 184 If you wish for all usermode helper programs are to be 185 disabled, choose this option and then set 186 STATIC_USERMODEHELPER_PATH to an empty string. 187 188config STATIC_USERMODEHELPER_PATH 189 string "Path to the static usermode helper binary" 190 depends on STATIC_USERMODEHELPER 191 default "/sbin/usermode-helper" 192 help 193 The binary called by the kernel when any usermode helper 194 program is wish to be run. The "real" application's name will 195 be in the first argument passed to this program on the command 196 line. 197 198 If you wish for all usermode helper programs to be disabled, 199 specify an empty string here (i.e. ""). 200 201source "security/selinux/Kconfig" 202source "security/smack/Kconfig" 203source "security/tomoyo/Kconfig" 204source "security/apparmor/Kconfig" 205source "security/loadpin/Kconfig" 206source "security/yama/Kconfig" 207source "security/safesetid/Kconfig" 208source "security/lockdown/Kconfig" 209source "security/landlock/Kconfig" 210 211source "security/integrity/Kconfig" 212 213choice 214 prompt "First legacy 'major LSM' to be initialized" 215 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX 216 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK 217 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO 218 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR 219 default DEFAULT_SECURITY_DAC 220 221 help 222 This choice is there only for converting CONFIG_DEFAULT_SECURITY 223 in old kernel configs to CONFIG_LSM in new kernel configs. Don't 224 change this choice unless you are creating a fresh kernel config, 225 for this choice will be ignored after CONFIG_LSM has been set. 226 227 Selects the legacy "major security module" that will be 228 initialized first. Overridden by non-default CONFIG_LSM. 229 230 config DEFAULT_SECURITY_SELINUX 231 bool "SELinux" if SECURITY_SELINUX=y 232 233 config DEFAULT_SECURITY_SMACK 234 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y 235 236 config DEFAULT_SECURITY_TOMOYO 237 bool "TOMOYO" if SECURITY_TOMOYO=y 238 239 config DEFAULT_SECURITY_APPARMOR 240 bool "AppArmor" if SECURITY_APPARMOR=y 241 242 config DEFAULT_SECURITY_DAC 243 bool "Unix Discretionary Access Controls" 244 245endchoice 246 247config LSM 248 string "Ordered list of enabled LSMs" 249 default "landlock,lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor,bpf" if DEFAULT_SECURITY_SMACK 250 default "landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo,bpf" if DEFAULT_SECURITY_APPARMOR 251 default "landlock,lockdown,yama,loadpin,safesetid,integrity,tomoyo,bpf" if DEFAULT_SECURITY_TOMOYO 252 default "landlock,lockdown,yama,loadpin,safesetid,integrity,bpf" if DEFAULT_SECURITY_DAC 253 default "landlock,lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor,bpf" 254 help 255 A comma-separated list of LSMs, in initialization order. 256 Any LSMs left off this list will be ignored. This can be 257 controlled at boot with the "lsm=" parameter. 258 259 If unsure, leave this as the default. 260 261source "security/Kconfig.hardening" 262 263endmenu 264 265