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 SECURITY_NETWORK_XFRM 58 bool "XFRM (IPSec) Networking Security Hooks" 59 depends on XFRM && SECURITY_NETWORK 60 help 61 This enables the XFRM (IPSec) networking security hooks. 62 If enabled, a security module can use these hooks to 63 implement per-packet access controls based on labels 64 derived from IPSec policy. Non-IPSec communications are 65 designated as unlabelled, and only sockets authorized 66 to communicate unlabelled data can send without using 67 IPSec. 68 If you are unsure how to answer this question, answer N. 69 70config SECURITY_PATH 71 bool "Security hooks for pathname based access control" 72 depends on SECURITY 73 help 74 This enables the security hooks for pathname based access control. 75 If enabled, a security module can use these hooks to 76 implement pathname based access controls. 77 If you are unsure how to answer this question, answer N. 78 79config INTEL_TXT 80 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)" 81 depends on HAVE_INTEL_TXT 82 help 83 This option enables support for booting the kernel with the 84 Trusted Boot (tboot) module. This will utilize 85 Intel(R) Trusted Execution Technology to perform a measured launch 86 of the kernel. If the system does not support Intel(R) TXT, this 87 will have no effect. 88 89 Intel TXT will provide higher assurance of system configuration and 90 initial state as well as data reset protection. This is used to 91 create a robust initial kernel measurement and verification, which 92 helps to ensure that kernel security mechanisms are functioning 93 correctly. This level of protection requires a root of trust outside 94 of the kernel itself. 95 96 Intel TXT also helps solve real end user concerns about having 97 confidence that their hardware is running the VMM or kernel that 98 it was configured with, especially since they may be responsible for 99 providing such assurances to VMs and services running on it. 100 101 See <http://www.intel.com/technology/security/> for more information 102 about Intel(R) TXT. 103 See <http://tboot.sourceforge.net> for more information about tboot. 104 See Documentation/intel_txt.txt for a description of how to enable 105 Intel TXT support in a kernel boot. 106 107 If you are unsure as to whether this is required, answer N. 108 109config LSM_MMAP_MIN_ADDR 110 int "Low address space for LSM to protect from user allocation" 111 depends on SECURITY && SECURITY_SELINUX 112 default 32768 if ARM || (ARM64 && COMPAT) 113 default 65536 114 help 115 This is the portion of low virtual memory which should be protected 116 from userspace allocation. Keeping a user from writing to low pages 117 can help reduce the impact of kernel NULL pointer bugs. 118 119 For most ia64, ppc64 and x86 users with lots of address space 120 a value of 65536 is reasonable and should cause no problems. 121 On arm and other archs it should not be higher than 32768. 122 Programs which use vm86 functionality or have some need to map 123 this low address space will need the permission specific to the 124 systems running LSM. 125 126config HAVE_HARDENED_USERCOPY_ALLOCATOR 127 bool 128 help 129 The heap allocator implements __check_heap_object() for 130 validating memory ranges against heap object sizes in 131 support of CONFIG_HARDENED_USERCOPY. 132 133config HAVE_ARCH_HARDENED_USERCOPY 134 bool 135 help 136 The architecture supports CONFIG_HARDENED_USERCOPY by 137 calling check_object_size() just before performing the 138 userspace copies in the low level implementation of 139 copy_to_user() and copy_from_user(). 140 141config HARDENED_USERCOPY 142 bool "Harden memory copies between kernel and userspace" 143 depends on HAVE_ARCH_HARDENED_USERCOPY 144 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR 145 select BUG 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 allocates pages, are not on the process stack, 152 or are part of the kernel text. This kills entire classes 153 of heap overflow exploits and similar kernel memory exposures. 154 155config HARDENED_USERCOPY_PAGESPAN 156 bool "Refuse to copy allocations that span multiple pages" 157 depends on HARDENED_USERCOPY 158 depends on EXPERT 159 help 160 When a multi-page allocation is done without __GFP_COMP, 161 hardened usercopy will reject attempts to copy it. There are, 162 however, several cases of this in the kernel that have not all 163 been removed. This config is intended to be used only while 164 trying to find such users. 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 207 208source security/integrity/Kconfig 209 210choice 211 prompt "Default security module" 212 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX 213 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK 214 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO 215 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR 216 default DEFAULT_SECURITY_DAC 217 218 help 219 Select the security module that will be used by default if the 220 kernel parameter security= is not specified. 221 222 config DEFAULT_SECURITY_SELINUX 223 bool "SELinux" if SECURITY_SELINUX=y 224 225 config DEFAULT_SECURITY_SMACK 226 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y 227 228 config DEFAULT_SECURITY_TOMOYO 229 bool "TOMOYO" if SECURITY_TOMOYO=y 230 231 config DEFAULT_SECURITY_APPARMOR 232 bool "AppArmor" if SECURITY_APPARMOR=y 233 234 config DEFAULT_SECURITY_DAC 235 bool "Unix Discretionary Access Controls" 236 237endchoice 238 239config DEFAULT_SECURITY 240 string 241 default "selinux" if DEFAULT_SECURITY_SELINUX 242 default "smack" if DEFAULT_SECURITY_SMACK 243 default "tomoyo" if DEFAULT_SECURITY_TOMOYO 244 default "apparmor" if DEFAULT_SECURITY_APPARMOR 245 default "" if DEFAULT_SECURITY_DAC 246 247endmenu 248 249