security/Kconfig

   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         depends on X86_64 && !UML
  60         default y
  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_PAGESPAN
 168         bool "Refuse to copy allocations that span multiple pages"
 169         depends on HARDENED_USERCOPY
 170         depends on EXPERT
 171         help
 172           When a multi-page allocation is done without __GFP_COMP,
 173           hardened usercopy will reject attempts to copy it. There are,
 174           however, several cases of this in the kernel that have not all
 175           been removed. This config is intended to be used only while
 176           trying to find such users.
 177
 178 config FORTIFY_SOURCE
 179         bool "Harden common str/mem functions against buffer overflows"
 180         depends on ARCH_HAS_FORTIFY_SOURCE
 181         help
 182           Detect overflows of buffers in common string and memory functions
 183           where the compiler can determine and validate the buffer sizes.
 184
 185 config STATIC_USERMODEHELPER
 186         bool "Force all usermode helper calls through a single binary"
 187         help
 188           By default, the kernel can call many different userspace
 189           binary programs through the "usermode helper" kernel
 190           interface.  Some of these binaries are statically defined
 191           either in the kernel code itself, or as a kernel configuration
 192           option.  However, some of these are dynamically created at
 193           runtime, or can be modified after the kernel has started up.
 194           To provide an additional layer of security, route all of these
 195           calls through a single executable that can not have its name
 196           changed.
 197
 198           Note, it is up to this single binary to then call the relevant
 199           "real" usermode helper binary, based on the first argument
 200           passed to it.  If desired, this program can filter and pick
 201           and choose what real programs are called.
 202
 203           If you wish for all usermode helper programs are to be
 204           disabled, choose this option and then set
 205           STATIC_USERMODEHELPER_PATH to an empty string.
 206
 207 config STATIC_USERMODEHELPER_PATH
 208         string "Path to the static usermode helper binary"
 209         depends on STATIC_USERMODEHELPER
 210         default "/sbin/usermode-helper"
 211         help
 212           The binary called by the kernel when any usermode helper
 213           program is wish to be run.  The "real" application's name will
 214           be in the first argument passed to this program on the command
 215           line.
 216
 217           If you wish for all usermode helper programs to be disabled,
 218           specify an empty string here (i.e. "").
 219
 220 source security/selinux/Kconfig
 221 source security/smack/Kconfig
 222 source security/tomoyo/Kconfig
 223 source security/apparmor/Kconfig
 224 source security/loadpin/Kconfig
 225 source security/yama/Kconfig
 226
 227 source security/integrity/Kconfig
 228
 229 choice
 230         prompt "Default security module"
 231         default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
 232         default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
 233         default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
 234         default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
 235         default DEFAULT_SECURITY_DAC
 236
 237         help
 238           Select the security module that will be used by default if the
 239           kernel parameter security= is not specified.
 240
 241         config DEFAULT_SECURITY_SELINUX
 242                 bool "SELinux" if SECURITY_SELINUX=y
 243
 244         config DEFAULT_SECURITY_SMACK
 245                 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
 246
 247         config DEFAULT_SECURITY_TOMOYO
 248                 bool "TOMOYO" if SECURITY_TOMOYO=y
 249
 250         config DEFAULT_SECURITY_APPARMOR
 251                 bool "AppArmor" if SECURITY_APPARMOR=y
 252
 253         config DEFAULT_SECURITY_DAC
 254                 bool "Unix Discretionary Access Controls"
 255
 256 endchoice
 257
 258 config DEFAULT_SECURITY
 259         string
 260         default "selinux" if DEFAULT_SECURITY_SELINUX
 261         default "smack" if DEFAULT_SECURITY_SMACK
 262         default "tomoyo" if DEFAULT_SECURITY_TOMOYO
 263         default "apparmor" if DEFAULT_SECURITY_APPARMOR
 264         default "" if DEFAULT_SECURITY_DAC
 265
 266 endmenu
 267