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_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
  70 config 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
  79 config 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
 109 config 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
 126 config 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
 133 config 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
 141 config 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 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 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
 188 config 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
 201 source security/selinux/Kconfig
 202 source security/smack/Kconfig
 203 source security/tomoyo/Kconfig
 204 source security/apparmor/Kconfig
 205 source security/loadpin/Kconfig
 206 source security/yama/Kconfig
 207
 208 source security/integrity/Kconfig
 209
 210 choice
 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
 237 endchoice
 238
 239 config 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
 247 endmenu
 248