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 SECURITY_INFINIBAND
  58         bool "Infiniband Security Hooks"
  59         depends on SECURITY && INFINIBAND
  60         help
  61           This enables the Infiniband security hooks.
  62           If enabled, a security module can use these hooks to
  63           implement Infiniband access controls.
  64           If you are unsure how to answer this question, answer N.
  65
  66 config SECURITY_NETWORK_XFRM
  67         bool "XFRM (IPSec) Networking Security Hooks"
  68         depends on XFRM && SECURITY_NETWORK
  69         help
  70           This enables the XFRM (IPSec) networking security hooks.
  71           If enabled, a security module can use these hooks to
  72           implement per-packet access controls based on labels
  73           derived from IPSec policy.  Non-IPSec communications are
  74           designated as unlabelled, and only sockets authorized
  75           to communicate unlabelled data can send without using
  76           IPSec.
  77           If you are unsure how to answer this question, answer N.
  78
  79 config SECURITY_PATH
  80         bool "Security hooks for pathname based access control"
  81         depends on SECURITY
  82         help
  83           This enables the security hooks for pathname based access control.
  84           If enabled, a security module can use these hooks to
  85           implement pathname based access controls.
  86           If you are unsure how to answer this question, answer N.
  87
  88 config INTEL_TXT
  89         bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
  90         depends on HAVE_INTEL_TXT
  91         help
  92           This option enables support for booting the kernel with the
  93           Trusted Boot (tboot) module. This will utilize
  94           Intel(R) Trusted Execution Technology to perform a measured launch
  95           of the kernel. If the system does not support Intel(R) TXT, this
  96           will have no effect.
  97
  98           Intel TXT will provide higher assurance of system configuration and
  99           initial state as well as data reset protection.  This is used to
 100           create a robust initial kernel measurement and verification, which
 101           helps to ensure that kernel security mechanisms are functioning
 102           correctly. This level of protection requires a root of trust outside
 103           of the kernel itself.
 104
 105           Intel TXT also helps solve real end user concerns about having
 106           confidence that their hardware is running the VMM or kernel that
 107           it was configured with, especially since they may be responsible for
 108           providing such assurances to VMs and services running on it.
 109
 110           See <http://www.intel.com/technology/security/> for more information
 111           about Intel(R) TXT.
 112           See <http://tboot.sourceforge.net> for more information about tboot.
 113           See Documentation/intel_txt.txt for a description of how to enable
 114           Intel TXT support in a kernel boot.
 115
 116           If you are unsure as to whether this is required, answer N.
 117
 118 config LSM_MMAP_MIN_ADDR
 119         int "Low address space for LSM to protect from user allocation"
 120         depends on SECURITY && SECURITY_SELINUX
 121         default 32768 if ARM || (ARM64 && COMPAT)
 122         default 65536
 123         help
 124           This is the portion of low virtual memory which should be protected
 125           from userspace allocation.  Keeping a user from writing to low pages
 126           can help reduce the impact of kernel NULL pointer bugs.
 127
 128           For most ia64, ppc64 and x86 users with lots of address space
 129           a value of 65536 is reasonable and should cause no problems.
 130           On arm and other archs it should not be higher than 32768.
 131           Programs which use vm86 functionality or have some need to map
 132           this low address space will need the permission specific to the
 133           systems running LSM.
 134
 135 config HAVE_HARDENED_USERCOPY_ALLOCATOR
 136         bool
 137         help
 138           The heap allocator implements __check_heap_object() for
 139           validating memory ranges against heap object sizes in
 140           support of CONFIG_HARDENED_USERCOPY.
 141
 142 config HARDENED_USERCOPY
 143         bool "Harden memory copies between kernel and userspace"
 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 allocated 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
 155 config 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
 166 config FORTIFY_SOURCE
 167         bool "Harden common str/mem functions against buffer overflows"
 168         depends on ARCH_HAS_FORTIFY_SOURCE
 169         help
 170           Detect overflows of buffers in common string and memory functions
 171           where the compiler can determine and validate the buffer sizes.
 172
 173 config STATIC_USERMODEHELPER
 174         bool "Force all usermode helper calls through a single binary"
 175         help
 176           By default, the kernel can call many different userspace
 177           binary programs through the "usermode helper" kernel
 178           interface.  Some of these binaries are statically defined
 179           either in the kernel code itself, or as a kernel configuration
 180           option.  However, some of these are dynamically created at
 181           runtime, or can be modified after the kernel has started up.
 182           To provide an additional layer of security, route all of these
 183           calls through a single executable that can not have its name
 184           changed.
 185
 186           Note, it is up to this single binary to then call the relevant
 187           "real" usermode helper binary, based on the first argument
 188           passed to it.  If desired, this program can filter and pick
 189           and choose what real programs are called.
 190
 191           If you wish for all usermode helper programs are to be
 192           disabled, choose this option and then set
 193           STATIC_USERMODEHELPER_PATH to an empty string.
 194
 195 config STATIC_USERMODEHELPER_PATH
 196         string "Path to the static usermode helper binary"
 197         depends on STATIC_USERMODEHELPER
 198         default "/sbin/usermode-helper"
 199         help
 200           The binary called by the kernel when any usermode helper
 201           program is wish to be run.  The "real" application's name will
 202           be in the first argument passed to this program on the command
 203           line.
 204
 205           If you wish for all usermode helper programs to be disabled,
 206           specify an empty string here (i.e. "").
 207
 208 source security/selinux/Kconfig
 209 source security/smack/Kconfig
 210 source security/tomoyo/Kconfig
 211 source security/apparmor/Kconfig
 212 source security/loadpin/Kconfig
 213 source security/yama/Kconfig
 214
 215 source security/integrity/Kconfig
 216
 217 choice
 218         prompt "Default security module"
 219         default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
 220         default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
 221         default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
 222         default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
 223         default DEFAULT_SECURITY_DAC
 224
 225         help
 226           Select the security module that will be used by default if the
 227           kernel parameter security= is not specified.
 228
 229         config DEFAULT_SECURITY_SELINUX
 230                 bool "SELinux" if SECURITY_SELINUX=y
 231
 232         config DEFAULT_SECURITY_SMACK
 233                 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
 234
 235         config DEFAULT_SECURITY_TOMOYO
 236                 bool "TOMOYO" if SECURITY_TOMOYO=y
 237
 238         config DEFAULT_SECURITY_APPARMOR
 239                 bool "AppArmor" if SECURITY_APPARMOR=y
 240
 241         config DEFAULT_SECURITY_DAC
 242                 bool "Unix Discretionary Access Controls"
 243
 244 endchoice
 245
 246 config DEFAULT_SECURITY
 247         string
 248         default "selinux" if DEFAULT_SECURITY_SELINUX
 249         default "smack" if DEFAULT_SECURITY_SMACK
 250         default "tomoyo" if DEFAULT_SECURITY_TOMOYO
 251         default "apparmor" if DEFAULT_SECURITY_APPARMOR
 252         default "" if DEFAULT_SECURITY_DAC
 253
 254 endmenu
 255