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 HARDENED_USERCOPY 134 bool "Harden memory copies between kernel and userspace" 135 depends on HAVE_HARDENED_USERCOPY_ALLOCATOR 136 select BUG 137 help 138 This option checks for obviously wrong memory regions when 139 copying memory to/from the kernel (via copy_to_user() and 140 copy_from_user() functions) by rejecting memory ranges that 141 are larger than the specified heap object, span multiple 142 separately allocates pages, are not on the process stack, 143 or are part of the kernel text. This kills entire classes 144 of heap overflow exploits and similar kernel memory exposures. 145 146config HARDENED_USERCOPY_PAGESPAN 147 bool "Refuse to copy allocations that span multiple pages" 148 depends on HARDENED_USERCOPY 149 depends on EXPERT 150 help 151 When a multi-page allocation is done without __GFP_COMP, 152 hardened usercopy will reject attempts to copy it. There are, 153 however, several cases of this in the kernel that have not all 154 been removed. This config is intended to be used only while 155 trying to find such users. 156 157config STATIC_USERMODEHELPER 158 bool "Force all usermode helper calls through a single binary" 159 help 160 By default, the kernel can call many different userspace 161 binary programs through the "usermode helper" kernel 162 interface. Some of these binaries are statically defined 163 either in the kernel code itself, or as a kernel configuration 164 option. However, some of these are dynamically created at 165 runtime, or can be modified after the kernel has started up. 166 To provide an additional layer of security, route all of these 167 calls through a single executable that can not have its name 168 changed. 169 170 Note, it is up to this single binary to then call the relevant 171 "real" usermode helper binary, based on the first argument 172 passed to it. If desired, this program can filter and pick 173 and choose what real programs are called. 174 175 If you wish for all usermode helper programs are to be 176 disabled, choose this option and then set 177 STATIC_USERMODEHELPER_PATH to an empty string. 178 179config STATIC_USERMODEHELPER_PATH 180 string "Path to the static usermode helper binary" 181 depends on STATIC_USERMODEHELPER 182 default "/sbin/usermode-helper" 183 help 184 The binary called by the kernel when any usermode helper 185 program is wish to be run. The "real" application's name will 186 be in the first argument passed to this program on the command 187 line. 188 189 If you wish for all usermode helper programs to be disabled, 190 specify an empty string here (i.e. ""). 191 192source security/selinux/Kconfig 193source security/smack/Kconfig 194source security/tomoyo/Kconfig 195source security/apparmor/Kconfig 196source security/loadpin/Kconfig 197source security/yama/Kconfig 198 199source security/integrity/Kconfig 200 201choice 202 prompt "Default security module" 203 default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX 204 default DEFAULT_SECURITY_SMACK if SECURITY_SMACK 205 default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO 206 default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR 207 default DEFAULT_SECURITY_DAC 208 209 help 210 Select the security module that will be used by default if the 211 kernel parameter security= is not specified. 212 213 config DEFAULT_SECURITY_SELINUX 214 bool "SELinux" if SECURITY_SELINUX=y 215 216 config DEFAULT_SECURITY_SMACK 217 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y 218 219 config DEFAULT_SECURITY_TOMOYO 220 bool "TOMOYO" if SECURITY_TOMOYO=y 221 222 config DEFAULT_SECURITY_APPARMOR 223 bool "AppArmor" if SECURITY_APPARMOR=y 224 225 config DEFAULT_SECURITY_DAC 226 bool "Unix Discretionary Access Controls" 227 228endchoice 229 230config DEFAULT_SECURITY 231 string 232 default "selinux" if DEFAULT_SECURITY_SELINUX 233 default "smack" if DEFAULT_SECURITY_SMACK 234 default "tomoyo" if DEFAULT_SECURITY_TOMOYO 235 default "apparmor" if DEFAULT_SECURITY_APPARMOR 236 default "" if DEFAULT_SECURITY_DAC 237 238endmenu 239 240