1# 2# Security configuration 3# 4 5menu "Security options" 6 7source security/keys/Kconfig 8 9config SECURITY_DMESG_RESTRICT 10 bool "Restrict unprivileged access to the kernel syslog" 11 default n 12 help 13 This enforces restrictions on unprivileged users reading the kernel 14 syslog via dmesg(8). 15 16 If this option is not selected, no restrictions will be enforced 17 unless the dmesg_restrict sysctl is explicitly set to (1). 18 19 If you are unsure how to answer this question, answer N. 20 21config SECURITY 22 bool "Enable different security models" 23 depends on SYSFS 24 depends on MULTIUSER 25 help 26 This allows you to choose different security modules to be 27 configured into your kernel. 28 29 If this option is not selected, the default Linux security 30 model will be used. 31 32 If you are unsure how to answer this question, answer N. 33 34config SECURITY_WRITABLE_HOOKS 35 depends on SECURITY 36 bool 37 default n 38 39config SECURITYFS 40 bool "Enable the securityfs filesystem" 41 help 42 This will build the securityfs filesystem. It is currently used by 43 the TPM bios character driver and IMA, an integrity provider. It is 44 not used by SELinux or SMACK. 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 PAGE_TABLE_ISOLATION 58 bool "Remove the kernel mapping in user mode" 59 depends on X86_64 && !UML 60 help 61 This feature reduces the number of hardware side channels by 62 ensuring that the majority of kernel addresses are not mapped 63 into userspace. 64 65 See Documentation/x86/pagetable-isolation.txt for more details. 66 67config SECURITY_INFINIBAND 68 bool "Infiniband Security Hooks" 69 depends on SECURITY && INFINIBAND 70 help 71 This enables the Infiniband security hooks. 72 If enabled, a security module can use these hooks to 73 implement Infiniband access controls. 74 If you are unsure how to answer this question, answer N. 75 76config SECURITY_NETWORK_XFRM 77 bool "XFRM (IPSec) Networking Security Hooks" 78 depends on XFRM && SECURITY_NETWORK 79 help 80 This enables the XFRM (IPSec) networking security hooks. 81 If enabled, a security module can use these hooks to 82 implement per-packet access controls based on labels 83 derived from IPSec policy. Non-IPSec communications are 84 designated as unlabelled, and only sockets authorized 85 to communicate unlabelled data can send without using 86 IPSec. 87 If you are unsure how to answer this question, answer N. 88 89config SECURITY_PATH 90 bool "Security hooks for pathname based access control" 91 depends on SECURITY 92 help 93 This enables the security hooks for pathname based access control. 94 If enabled, a security module can use these hooks to 95 implement pathname based access controls. 96 If you are unsure how to answer this question, answer N. 97 98config INTEL_TXT 99 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)" 100 depends on HAVE_INTEL_TXT 101 help 102 This option enables support for booting the kernel with the 103 Trusted Boot (tboot) module. This will utilize 104 Intel(R) Trusted Execution Technology to perform a measured launch 105 of the kernel. If the system does not support Intel(R) TXT, this 106 will have no effect. 107 108 Intel TXT will provide higher assurance of system configuration and 109 initial state as well as data reset protection. This is used to 110 create a robust initial kernel measurement and verification, which 111 helps to ensure that kernel security mechanisms are functioning 112 correctly. This level of protection requires a root of trust outside 113 of the kernel itself. 114 115 Intel TXT also helps solve real end user concerns about having 116 confidence that their hardware is running the VMM or kernel that 117 it was configured with, especially since they may be responsible for 118 providing such assurances to VMs and services running on it. 119 120 See <http://www.intel.com/technology/security/> for more information 121 about Intel(R) TXT. 122 See <http://tboot.sourceforge.net> for more information about tboot. 123 See Documentation/intel_txt.txt for a description of how to enable 124 Intel TXT support in a kernel boot. 125 126 If you are unsure as to whether this is required, answer N. 127 128config LSM_MMAP_MIN_ADDR 129 int "Low address space for LSM to protect from user allocation" 130 depends on SECURITY && SECURITY_SELINUX 131 default 32768 if ARM || (ARM64 && COMPAT) 132 default 65536 133 help 134 This is the portion of low virtual memory which should be protected 135 from userspace allocation. Keeping a user from writing to low pages 136 can help reduce the impact of kernel NULL pointer bugs. 137 138 For most ia64, ppc64 and x86 users with lots of address space 139 a value of 65536 is reasonable and should cause no problems. 140 On arm and other archs it should not be higher than 32768. 141 Programs which use vm86 functionality or have some need to map 142 this low address space will need the permission specific to the 143 systems running LSM. 144 145config HAVE_HARDENED_USERCOPY_ALLOCATOR 146 bool 147 help 148 The heap allocator implements __check_heap_object() for 149 validating memory ranges against heap object sizes in 150 support of CONFIG_HARDENED_USERCOPY. 151 152config HARDENED_USERCOPY 153 bool "Harden memory copies between kernel and userspace" 154 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR 155 select BUG 156 help 157 This option checks for obviously wrong memory regions when 158 copying memory to/from the kernel (via copy_to_user() and 159 copy_from_user() functions) by rejecting memory ranges that 160 are larger than the specified heap object, span multiple 161 separately allocated pages, are not on the process stack, 162 or are part of the kernel text. This kills entire classes 163 of heap overflow exploits and similar kernel memory exposures. 164 165config HARDENED_USERCOPY_PAGESPAN 166 bool "Refuse to copy allocations that span multiple pages" 167 depends on HARDENED_USERCOPY 168 depends on EXPERT 169 help 170 When a multi-page allocation is done without __GFP_COMP, 171 hardened usercopy will reject attempts to copy it. There are, 172 however, several cases of this in the kernel that have not all 173 been removed. This config is intended to be used only while 174 trying to find such users. 175 176config FORTIFY_SOURCE 177 bool "Harden common str/mem functions against buffer overflows" 178 depends on ARCH_HAS_FORTIFY_SOURCE 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 183config 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 205config 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 218source security/selinux/Kconfig 219source security/smack/Kconfig 220source security/tomoyo/Kconfig 221source security/apparmor/Kconfig 222source security/loadpin/Kconfig 223source security/yama/Kconfig 224 225source security/integrity/Kconfig 226 227choice 228 prompt "Default security module" 229 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX 230 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK 231 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO 232 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR 233 default DEFAULT_SECURITY_DAC 234 235 help 236 Select the security module that will be used by default if the 237 kernel parameter security= is not specified. 238 239 config DEFAULT_SECURITY_SELINUX 240 bool "SELinux" if SECURITY_SELINUX=y 241 242 config DEFAULT_SECURITY_SMACK 243 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y 244 245 config DEFAULT_SECURITY_TOMOYO 246 bool "TOMOYO" if SECURITY_TOMOYO=y 247 248 config DEFAULT_SECURITY_APPARMOR 249 bool "AppArmor" if SECURITY_APPARMOR=y 250 251 config DEFAULT_SECURITY_DAC 252 bool "Unix Discretionary Access Controls" 253 254endchoice 255 256config DEFAULT_SECURITY 257 string 258 default "selinux" if DEFAULT_SECURITY_SELINUX 259 default "smack" if DEFAULT_SECURITY_SMACK 260 default "tomoyo" if DEFAULT_SECURITY_TOMOYO 261 default "apparmor" if DEFAULT_SECURITY_APPARMOR 262 default "" if DEFAULT_SECURITY_DAC 263 264endmenu 265 266