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_PERF_EVENTS_RESTRICT
  22         bool "Restrict unprivileged use of performance events"
  23         depends on PERF_EVENTS
  24         help
  25           If you say Y here, the kernel.perf_event_paranoid sysctl
  26           will be set to 3 by default, and no unprivileged use of the
  27           perf_event_open syscall will be permitted unless it is
  28           changed.
  29
  30 config SECURITY
  31         bool "Enable different security models"
  32         depends on SYSFS
  33         depends on MULTIUSER
  34         help
  35           This allows you to choose different security modules to be
  36           configured into your kernel.
  37
  38           If this option is not selected, the default Linux security
  39           model will be used.
  40
  41           If you are unsure how to answer this question, answer N.
  42
  43 config SECURITY_WRITABLE_HOOKS
  44         depends on SECURITY
  45         bool
  46         default n
  47
  48 config SECURITYFS
  49         bool "Enable the securityfs filesystem"
  50         help
  51           This will build the securityfs filesystem.  It is currently used by
  52           the TPM bios character driver and IMA, an integrity provider.  It is
  53           not used by SELinux or SMACK.
  54
  55           If you are unsure how to answer this question, answer N.
  56
  57 config SECURITY_NETWORK
  58         bool "Socket and Networking Security Hooks"
  59         depends on SECURITY
  60         help
  61           This enables the socket and networking security hooks.
  62           If enabled, a security module can use these hooks to
  63           implement socket and networking access controls.
  64           If you are unsure how to answer this question, answer N.
  65
  66 config SECURITY_INFINIBAND
  67         bool "Infiniband Security Hooks"
  68         depends on SECURITY && INFINIBAND
  69         help
  70           This enables the Infiniband security hooks.
  71           If enabled, a security module can use these hooks to
  72           implement Infiniband access controls.
  73           If you are unsure how to answer this question, answer N.
  74
  75 config SECURITY_NETWORK_XFRM
  76         bool "XFRM (IPSec) Networking Security Hooks"
  77         depends on XFRM && SECURITY_NETWORK
  78         help
  79           This enables the XFRM (IPSec) networking security hooks.
  80           If enabled, a security module can use these hooks to
  81           implement per-packet access controls based on labels
  82           derived from IPSec policy.  Non-IPSec communications are
  83           designated as unlabelled, and only sockets authorized
  84           to communicate unlabelled data can send without using
  85           IPSec.
  86           If you are unsure how to answer this question, answer N.
  87
  88 config SECURITY_PATH
  89         bool "Security hooks for pathname based access control"
  90         depends on SECURITY
  91         help
  92           This enables the security hooks for pathname based access control.
  93           If enabled, a security module can use these hooks to
  94           implement pathname based access controls.
  95           If you are unsure how to answer this question, answer N.
  96
  97 config INTEL_TXT
  98         bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
  99         depends on HAVE_INTEL_TXT
 100         help
 101           This option enables support for booting the kernel with the
 102           Trusted Boot (tboot) module. This will utilize
 103           Intel(R) Trusted Execution Technology to perform a measured launch
 104           of the kernel. If the system does not support Intel(R) TXT, this
 105           will have no effect.
 106
 107           Intel TXT will provide higher assurance of system configuration and
 108           initial state as well as data reset protection.  This is used to
 109           create a robust initial kernel measurement and verification, which
 110           helps to ensure that kernel security mechanisms are functioning
 111           correctly. This level of protection requires a root of trust outside
 112           of the kernel itself.
 113
 114           Intel TXT also helps solve real end user concerns about having
 115           confidence that their hardware is running the VMM or kernel that
 116           it was configured with, especially since they may be responsible for
 117           providing such assurances to VMs and services running on it.
 118
 119           See <http://www.intel.com/technology/security/> for more information
 120           about Intel(R) TXT.
 121           See <http://tboot.sourceforge.net> for more information about tboot.
 122           See Documentation/intel_txt.txt for a description of how to enable
 123           Intel TXT support in a kernel boot.
 124
 125           If you are unsure as to whether this is required, answer N.
 126
 127 config LSM_MMAP_MIN_ADDR
 128         int "Low address space for LSM to protect from user allocation"
 129         depends on SECURITY && SECURITY_SELINUX
 130         default 32768 if ARM || (ARM64 && COMPAT)
 131         default 65536
 132         help
 133           This is the portion of low virtual memory which should be protected
 134           from userspace allocation.  Keeping a user from writing to low pages
 135           can help reduce the impact of kernel NULL pointer bugs.
 136
 137           For most ia64, ppc64 and x86 users with lots of address space
 138           a value of 65536 is reasonable and should cause no problems.
 139           On arm and other archs it should not be higher than 32768.
 140           Programs which use vm86 functionality or have some need to map
 141           this low address space will need the permission specific to the
 142           systems running LSM.
 143
 144 config HAVE_HARDENED_USERCOPY_ALLOCATOR
 145         bool
 146         help
 147           The heap allocator implements __check_heap_object() for
 148           validating memory ranges against heap object sizes in
 149           support of CONFIG_HARDENED_USERCOPY.
 150
 151 config HARDENED_USERCOPY
 152         bool "Harden memory copies between kernel and userspace"
 153         depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
 154         select BUG
 155         help
 156           This option checks for obviously wrong memory regions when
 157           copying memory to/from the kernel (via copy_to_user() and
 158           copy_from_user() functions) by rejecting memory ranges that
 159           are larger than the specified heap object, span multiple
 160           separately allocated pages, are not on the process stack,
 161           or are part of the kernel text. This kills entire classes
 162           of heap overflow exploits and similar kernel memory exposures.
 163
 164 config HARDENED_USERCOPY_PAGESPAN
 165         bool "Refuse to copy allocations that span multiple pages"
 166         depends on HARDENED_USERCOPY
 167         depends on EXPERT
 168         help
 169           When a multi-page allocation is done without __GFP_COMP,
 170           hardened usercopy will reject attempts to copy it. There are,
 171           however, several cases of this in the kernel that have not all
 172           been removed. This config is intended to be used only while
 173           trying to find such users.
 174
 175 config FORTIFY_SOURCE
 176         bool "Harden common str/mem functions against buffer overflows"
 177         depends on ARCH_HAS_FORTIFY_SOURCE
 178         help
 179           Detect overflows of buffers in common string and memory functions
 180           where the compiler can determine and validate the buffer sizes.
 181
 182 config STATIC_USERMODEHELPER
 183         bool "Force all usermode helper calls through a single binary"
 184         help
 185           By default, the kernel can call many different userspace
 186           binary programs through the "usermode helper" kernel
 187           interface.  Some of these binaries are statically defined
 188           either in the kernel code itself, or as a kernel configuration
 189           option.  However, some of these are dynamically created at
 190           runtime, or can be modified after the kernel has started up.
 191           To provide an additional layer of security, route all of these
 192           calls through a single executable that can not have its name
 193           changed.
 194
 195           Note, it is up to this single binary to then call the relevant
 196           "real" usermode helper binary, based on the first argument
 197           passed to it.  If desired, this program can filter and pick
 198           and choose what real programs are called.
 199
 200           If you wish for all usermode helper programs are to be
 201           disabled, choose this option and then set
 202           STATIC_USERMODEHELPER_PATH to an empty string.
 203
 204 config STATIC_USERMODEHELPER_PATH
 205         string "Path to the static usermode helper binary"
 206         depends on STATIC_USERMODEHELPER
 207         default "/sbin/usermode-helper"
 208         help
 209           The binary called by the kernel when any usermode helper
 210           program is wish to be run.  The "real" application's name will
 211           be in the first argument passed to this program on the command
 212           line.
 213
 214           If you wish for all usermode helper programs to be disabled,
 215           specify an empty string here (i.e. "").
 216
 217 source security/selinux/Kconfig
 218 source security/smack/Kconfig
 219 source security/tomoyo/Kconfig
 220 source security/apparmor/Kconfig
 221 source security/loadpin/Kconfig
 222 source security/yama/Kconfig
 223
 224 source security/integrity/Kconfig
 225
 226 choice
 227         prompt "Default security module"
 228         default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
 229         default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
 230         default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
 231         default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
 232         default DEFAULT_SECURITY_DAC
 233
 234         help
 235           Select the security module that will be used by default if the
 236           kernel parameter security= is not specified.
 237
 238         config DEFAULT_SECURITY_SELINUX
 239                 bool "SELinux" if SECURITY_SELINUX=y
 240
 241         config DEFAULT_SECURITY_SMACK
 242                 bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y
 243
 244         config DEFAULT_SECURITY_TOMOYO
 245                 bool "TOMOYO" if SECURITY_TOMOYO=y
 246
 247         config DEFAULT_SECURITY_APPARMOR
 248                 bool "AppArmor" if SECURITY_APPARMOR=y
 249
 250         config DEFAULT_SECURITY_DAC
 251                 bool "Unix Discretionary Access Controls"
 252
 253 endchoice
 254
 255 config DEFAULT_SECURITY
 256         string
 257         default "selinux" if DEFAULT_SECURITY_SELINUX
 258         default "smack" if DEFAULT_SECURITY_SMACK
 259         default "tomoyo" if DEFAULT_SECURITY_TOMOYO
 260         default "apparmor" if DEFAULT_SECURITY_APPARMOR
 261         default "" if DEFAULT_SECURITY_DAC
 262
 263 endmenu
 264