| 1 | # |
| 2 | # Security configuration |
| 3 | # |
| 4 | |
| 5 | menu "Security options" |
| 6 | |
| 7 | source security/keys/Kconfig |
| 8 | |
| 9 | config 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 | |
| 21 | config 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 | |
| 34 | config SECURITY_WRITABLE_HOOKS |
| 35 | depends on SECURITY |
| 36 | bool |
| 37 | default n |
| 38 | |
| 39 | config 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 | |
| 48 | config 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 | |
| 57 | config PAGE_TABLE_ISOLATION |
| 58 | bool "Remove the kernel mapping in user mode" |
| 59 | default y |
| 60 | depends on X86_64 && !UML |
| 61 | help |
| 62 | This feature reduces the number of hardware side channels by |
| 63 | ensuring that the majority of kernel addresses are not mapped |
| 64 | into userspace. |
| 65 | |
| 66 | See Documentation/x86/pti.txt for more details. |
| 67 | |
| 68 | config SECURITY_INFINIBAND |
| 69 | bool "Infiniband Security Hooks" |
| 70 | depends on SECURITY && INFINIBAND |
| 71 | help |
| 72 | This enables the Infiniband security hooks. |
| 73 | If enabled, a security module can use these hooks to |
| 74 | implement Infiniband access controls. |
| 75 | If you are unsure how to answer this question, answer N. |
| 76 | |
| 77 | config SECURITY_NETWORK_XFRM |
| 78 | bool "XFRM (IPSec) Networking Security Hooks" |
| 79 | depends on XFRM && SECURITY_NETWORK |
| 80 | help |
| 81 | This enables the XFRM (IPSec) networking security hooks. |
| 82 | If enabled, a security module can use these hooks to |
| 83 | implement per-packet access controls based on labels |
| 84 | derived from IPSec policy. Non-IPSec communications are |
| 85 | designated as unlabelled, and only sockets authorized |
| 86 | to communicate unlabelled data can send without using |
| 87 | IPSec. |
| 88 | If you are unsure how to answer this question, answer N. |
| 89 | |
| 90 | config SECURITY_PATH |
| 91 | bool "Security hooks for pathname based access control" |
| 92 | depends on SECURITY |
| 93 | help |
| 94 | This enables the security hooks for pathname based access control. |
| 95 | If enabled, a security module can use these hooks to |
| 96 | implement pathname based access controls. |
| 97 | If you are unsure how to answer this question, answer N. |
| 98 | |
| 99 | config INTEL_TXT |
| 100 | bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)" |
| 101 | depends on HAVE_INTEL_TXT |
| 102 | help |
| 103 | This option enables support for booting the kernel with the |
| 104 | Trusted Boot (tboot) module. This will utilize |
| 105 | Intel(R) Trusted Execution Technology to perform a measured launch |
| 106 | of the kernel. If the system does not support Intel(R) TXT, this |
| 107 | will have no effect. |
| 108 | |
| 109 | Intel TXT will provide higher assurance of system configuration and |
| 110 | initial state as well as data reset protection. This is used to |
| 111 | create a robust initial kernel measurement and verification, which |
| 112 | helps to ensure that kernel security mechanisms are functioning |
| 113 | correctly. This level of protection requires a root of trust outside |
| 114 | of the kernel itself. |
| 115 | |
| 116 | Intel TXT also helps solve real end user concerns about having |
| 117 | confidence that their hardware is running the VMM or kernel that |
| 118 | it was configured with, especially since they may be responsible for |
| 119 | providing such assurances to VMs and services running on it. |
| 120 | |
| 121 | See <http://www.intel.com/technology/security/> for more information |
| 122 | about Intel(R) TXT. |
| 123 | See <http://tboot.sourceforge.net> for more information about tboot. |
| 124 | See Documentation/intel_txt.txt for a description of how to enable |
| 125 | Intel TXT support in a kernel boot. |
| 126 | |
| 127 | If you are unsure as to whether this is required, answer N. |
| 128 | |
| 129 | config LSM_MMAP_MIN_ADDR |
| 130 | int "Low address space for LSM to protect from user allocation" |
| 131 | depends on SECURITY && SECURITY_SELINUX |
| 132 | default 32768 if ARM || (ARM64 && COMPAT) |
| 133 | default 65536 |
| 134 | help |
| 135 | This is the portion of low virtual memory which should be protected |
| 136 | from userspace allocation. Keeping a user from writing to low pages |
| 137 | can help reduce the impact of kernel NULL pointer bugs. |
| 138 | |
| 139 | For most ia64, ppc64 and x86 users with lots of address space |
| 140 | a value of 65536 is reasonable and should cause no problems. |
| 141 | On arm and other archs it should not be higher than 32768. |
| 142 | Programs which use vm86 functionality or have some need to map |
| 143 | this low address space will need the permission specific to the |
| 144 | systems running LSM. |
| 145 | |
| 146 | config HAVE_HARDENED_USERCOPY_ALLOCATOR |
| 147 | bool |
| 148 | help |
| 149 | The heap allocator implements __check_heap_object() for |
| 150 | validating memory ranges against heap object sizes in |
| 151 | support of CONFIG_HARDENED_USERCOPY. |
| 152 | |
| 153 | config HARDENED_USERCOPY |
| 154 | bool "Harden memory copies between kernel and userspace" |
| 155 | depends on HAVE_HARDENED_USERCOPY_ALLOCATOR |
| 156 | select BUG |
| 157 | imply STRICT_DEVMEM |
| 158 | help |
| 159 | This option checks for obviously wrong memory regions when |
| 160 | copying memory to/from the kernel (via copy_to_user() and |
| 161 | copy_from_user() functions) by rejecting memory ranges that |
| 162 | are larger than the specified heap object, span multiple |
| 163 | separately allocated pages, are not on the process stack, |
| 164 | or are part of the kernel text. This kills entire classes |
| 165 | of heap overflow exploits and similar kernel memory exposures. |
| 166 | |
| 167 | config HARDENED_USERCOPY_FALLBACK |
| 168 | bool "Allow usercopy whitelist violations to fallback to object size" |
| 169 | depends on HARDENED_USERCOPY |
| 170 | default y |
| 171 | help |
| 172 | This is a temporary option that allows missing usercopy whitelists |
| 173 | to be discovered via a WARN() to the kernel log, instead of |
| 174 | rejecting the copy, falling back to non-whitelisted hardened |
| 175 | usercopy that checks the slab allocation size instead of the |
| 176 | whitelist size. This option will be removed once it seems like |
| 177 | all missing usercopy whitelists have been identified and fixed. |
| 178 | Booting with "slab_common.usercopy_fallback=Y/N" can change |
| 179 | this setting. |
| 180 | |
| 181 | config HARDENED_USERCOPY_PAGESPAN |
| 182 | bool "Refuse to copy allocations that span multiple pages" |
| 183 | depends on HARDENED_USERCOPY |
| 184 | depends on EXPERT |
| 185 | help |
| 186 | When a multi-page allocation is done without __GFP_COMP, |
| 187 | hardened usercopy will reject attempts to copy it. There are, |
| 188 | however, several cases of this in the kernel that have not all |
| 189 | been removed. This config is intended to be used only while |
| 190 | trying to find such users. |
| 191 | |
| 192 | config FORTIFY_SOURCE |
| 193 | bool "Harden common str/mem functions against buffer overflows" |
| 194 | depends on ARCH_HAS_FORTIFY_SOURCE |
| 195 | help |
| 196 | Detect overflows of buffers in common string and memory functions |
| 197 | where the compiler can determine and validate the buffer sizes. |
| 198 | |
| 199 | config STATIC_USERMODEHELPER |
| 200 | bool "Force all usermode helper calls through a single binary" |
| 201 | help |
| 202 | By default, the kernel can call many different userspace |
| 203 | binary programs through the "usermode helper" kernel |
| 204 | interface. Some of these binaries are statically defined |
| 205 | either in the kernel code itself, or as a kernel configuration |
| 206 | option. However, some of these are dynamically created at |
| 207 | runtime, or can be modified after the kernel has started up. |
| 208 | To provide an additional layer of security, route all of these |
| 209 | calls through a single executable that can not have its name |
| 210 | changed. |
| 211 | |
| 212 | Note, it is up to this single binary to then call the relevant |
| 213 | "real" usermode helper binary, based on the first argument |
| 214 | passed to it. If desired, this program can filter and pick |
| 215 | and choose what real programs are called. |
| 216 | |
| 217 | If you wish for all usermode helper programs are to be |
| 218 | disabled, choose this option and then set |
| 219 | STATIC_USERMODEHELPER_PATH to an empty string. |
| 220 | |
| 221 | config STATIC_USERMODEHELPER_PATH |
| 222 | string "Path to the static usermode helper binary" |
| 223 | depends on STATIC_USERMODEHELPER |
| 224 | default "/sbin/usermode-helper" |
| 225 | help |
| 226 | The binary called by the kernel when any usermode helper |
| 227 | program is wish to be run. The "real" application's name will |
| 228 | be in the first argument passed to this program on the command |
| 229 | line. |
| 230 | |
| 231 | If you wish for all usermode helper programs to be disabled, |
| 232 | specify an empty string here (i.e. ""). |
| 233 | |
| 234 | source security/selinux/Kconfig |
| 235 | source security/smack/Kconfig |
| 236 | source security/tomoyo/Kconfig |
| 237 | source security/apparmor/Kconfig |
| 238 | source security/loadpin/Kconfig |
| 239 | source security/yama/Kconfig |
| 240 | |
| 241 | source security/integrity/Kconfig |
| 242 | |
| 243 | choice |
| 244 | prompt "Default security module" |
| 245 | default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX |
| 246 | default DEFAULT_SECURITY_SMACK if SECURITY_SMACK |
| 247 | default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO |
| 248 | default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR |
| 249 | default DEFAULT_SECURITY_DAC |
| 250 | |
| 251 | help |
| 252 | Select the security module that will be used by default if the |
| 253 | kernel parameter security= is not specified. |
| 254 | |
| 255 | config DEFAULT_SECURITY_SELINUX |
| 256 | bool "SELinux" if SECURITY_SELINUX=y |
| 257 | |
| 258 | config DEFAULT_SECURITY_SMACK |
| 259 | bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y |
| 260 | |
| 261 | config DEFAULT_SECURITY_TOMOYO |
| 262 | bool "TOMOYO" if SECURITY_TOMOYO=y |
| 263 | |
| 264 | config DEFAULT_SECURITY_APPARMOR |
| 265 | bool "AppArmor" if SECURITY_APPARMOR=y |
| 266 | |
| 267 | config DEFAULT_SECURITY_DAC |
| 268 | bool "Unix Discretionary Access Controls" |
| 269 | |
| 270 | endchoice |
| 271 | |
| 272 | config DEFAULT_SECURITY |
| 273 | string |
| 274 | default "selinux" if DEFAULT_SECURITY_SELINUX |
| 275 | default "smack" if DEFAULT_SECURITY_SMACK |
| 276 | default "tomoyo" if DEFAULT_SECURITY_TOMOYO |
| 277 | default "apparmor" if DEFAULT_SECURITY_APPARMOR |
| 278 | default "" if DEFAULT_SECURITY_DAC |
| 279 | |
| 280 | endmenu |
| 281 | |