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 SECURITYFS
  35         bool "Enable the securityfs filesystem"
  36         help
  37           This will build the securityfs filesystem.  It is currently used by
  38           the TPM bios character driver and IMA, an integrity provider.  It is
  39           not used by SELinux or SMACK.
  40
  41           If you are unsure how to answer this question, answer N.
  42
  43 config SECURITY_NETWORK
  44         bool "Socket and Networking Security Hooks"
  45         depends on SECURITY
  46         help
  47           This enables the socket and networking security hooks.
  48           If enabled, a security module can use these hooks to
  49           implement socket and networking access controls.
  50           If you are unsure how to answer this question, answer N.
  51
  52 config SECURITY_NETWORK_XFRM
  53         bool "XFRM (IPSec) Networking Security Hooks"
  54         depends on XFRM && SECURITY_NETWORK
  55         help
  56           This enables the XFRM (IPSec) networking security hooks.
  57           If enabled, a security module can use these hooks to
  58           implement per-packet access controls based on labels
  59           derived from IPSec policy.  Non-IPSec communications are
  60           designated as unlabelled, and only sockets authorized
  61           to communicate unlabelled data can send without using
  62           IPSec.
  63           If you are unsure how to answer this question, answer N.
  64
  65 config SECURITY_PATH
  66         bool "Security hooks for pathname based access control"
  67         depends on SECURITY
  68         help
  69           This enables the security hooks for pathname based access control.
  70           If enabled, a security module can use these hooks to
  71           implement pathname based access controls.
  72           If you are unsure how to answer this question, answer N.
  73
  74 config INTEL_TXT
  75         bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
  76         depends on HAVE_INTEL_TXT
  77         help
  78           This option enables support for booting the kernel with the
  79           Trusted Boot (tboot) module. This will utilize
  80           Intel(R) Trusted Execution Technology to perform a measured launch
  81           of the kernel. If the system does not support Intel(R) TXT, this
  82           will have no effect.
  83
  84           Intel TXT will provide higher assurance of system configuration and
  85           initial state as well as data reset protection.  This is used to
  86           create a robust initial kernel measurement and verification, which
  87           helps to ensure that kernel security mechanisms are functioning
  88           correctly. This level of protection requires a root of trust outside
  89           of the kernel itself.
  90
  91           Intel TXT also helps solve real end user concerns about having
  92           confidence that their hardware is running the VMM or kernel that
  93           it was configured with, especially since they may be responsible for
  94           providing such assurances to VMs and services running on it.
  95
  96           See <http://www.intel.com/technology/security/> for more information
  97           about Intel(R) TXT.
  98           See <http://tboot.sourceforge.net> for more information about tboot.
  99           See Documentation/intel_txt.txt for a description of how to enable
 100           Intel TXT support in a kernel boot.
 101
 102           If you are unsure as to whether this is required, answer N.
 103
 104 config LSM_MMAP_MIN_ADDR
 105         int "Low address space for LSM to protect from user allocation"
 106         depends on SECURITY && SECURITY_SELINUX
 107         default 32768 if ARM || (ARM64 && COMPAT)
 108         default 65536
 109         help
 110           This is the portion of low virtual memory which should be protected
 111           from userspace allocation.  Keeping a user from writing to low pages
 112           can help reduce the impact of kernel NULL pointer bugs.
 113
 114           For most ia64, ppc64 and x86 users with lots of address space
 115           a value of 65536 is reasonable and should cause no problems.
 116           On arm and other archs it should not be higher than 32768.
 117           Programs which use vm86 functionality or have some need to map
 118           this low address space will need the permission specific to the
 119           systems running LSM.
 120
 121 config HAVE_HARDENED_USERCOPY_ALLOCATOR
 122         bool
 123         help
 124           The heap allocator implements __check_heap_object() for
 125           validating memory ranges against heap object sizes in
 126           support of CONFIG_HARDENED_USERCOPY.
 127
 128 config HAVE_ARCH_HARDENED_USERCOPY
 129         bool
 130         help
 131           The architecture supports CONFIG_HARDENED_USERCOPY by
 132           calling check_object_size() just before performing the
 133           userspace copies in the low level implementation of
 134           copy_to_user() and copy_from_user().
 135
 136 config HARDENED_USERCOPY
 137         bool "Harden memory copies between kernel and userspace"
 138         depends on HAVE_ARCH_HARDENED_USERCOPY
 139         depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
 140         select BUG
 141         help
 142           This option checks for obviously wrong memory regions when
 143           copying memory to/from the kernel (via copy_to_user() and
 144           copy_from_user() functions) by rejecting memory ranges that
 145           are larger than the specified heap object, span multiple
 146           separately allocates pages, are not on the process stack,
 147           or are part of the kernel text. This kills entire classes
 148           of heap overflow exploits and similar kernel memory exposures.
 149
 150 config HARDENED_USERCOPY_PAGESPAN
 151         bool "Refuse to copy allocations that span multiple pages"
 152         depends on HARDENED_USERCOPY
 153         depends on EXPERT
 154         help
 155           When a multi-page allocation is done without __GFP_COMP,
 156           hardened usercopy will reject attempts to copy it. There are,
 157           however, several cases of this in the kernel that have not all
 158           been removed. This config is intended to be used only while
 159           trying to find such users.
 160
 161 config STATIC_USERMODEHELPER
 162         bool "Force all usermode helper calls through a single binary"
 163         help
 164           By default, the kernel can call many different userspace
 165           binary programs through the "usermode helper" kernel
 166           interface.  Some of these binaries are statically defined
 167           either in the kernel code itself, or as a kernel configuration
 168           option.  However, some of these are dynamically created at
 169           runtime, or can be modified after the kernel has started up.
 170           To provide an additional layer of security, route all of these
 171           calls through a single executable that can not have its name
 172           changed.
 173
 174           Note, it is up to this single binary to then call the relevant
 175           "real" usermode helper binary, based on the first argument
 176           passed to it.  If desired, this program can filter and pick
 177           and choose what real programs are called.
 178
 179           If you wish for all usermode helper programs are to be
 180           disabled, choose this option and then set
 181           STATIC_USERMODEHELPER_PATH to an empty string.
 182
 183 config STATIC_USERMODEHELPER_PATH
 184         string "Path to the static usermode helper binary"
 185         depends on STATIC_USERMODEHELPER
 186         default "/sbin/usermode-helper"
 187         help
 188           The binary called by the kernel when any usermode helper
 189           program is wish to be run.  The "real" application's name will
 190           be in the first argument passed to this program on the command
 191           line.
 192
 193           If you wish for all usermode helper programs to be disabled,
 194           specify an empty string here (i.e. "").
 195
 196 source security/selinux/Kconfig
 197 source security/smack/Kconfig
 198 source security/tomoyo/Kconfig
 199 source security/apparmor/Kconfig
 200 source security/loadpin/Kconfig
 201 source security/yama/Kconfig
 202
 203 source security/integrity/Kconfig
 204
 205 choice
 206         prompt "Default security module"
 207         default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
 208         default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
 209         default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
 210         default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
 211         default DEFAULT_SECURITY_DAC
 212
 213         help
 214           Select the security module that will be used by default if the
 215           kernel parameter security= is not specified.
 216
 217         config DEFAULT_SECURITY_SELINUX
 218                 bool "SELinux" if SECURITY_SELINUX=y
 219
 220         config DEFAULT_SECURITY_SMACK
 221                 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
 222
 223         config DEFAULT_SECURITY_TOMOYO
 224                 bool "TOMOYO" if SECURITY_TOMOYO=y
 225
 226         config DEFAULT_SECURITY_APPARMOR
 227                 bool "AppArmor" if SECURITY_APPARMOR=y
 228
 229         config DEFAULT_SECURITY_DAC
 230                 bool "Unix Discretionary Access Controls"
 231
 232 endchoice
 233
 234 config DEFAULT_SECURITY
 235         string
 236         default "selinux" if DEFAULT_SECURITY_SELINUX
 237         default "smack" if DEFAULT_SECURITY_SMACK
 238         default "tomoyo" if DEFAULT_SECURITY_TOMOYO
 239         default "apparmor" if DEFAULT_SECURITY_APPARMOR
 240         default "" if DEFAULT_SECURITY_DAC
 241
 242 endmenu
 243