security/Kconfig

#
# Security configuration
#

menu "Security options"

config KEYS
    bool "Enable access key retention support"
    help
      This option provides support for retaining authentication tokens and
      access keys in the kernel.

      It also includes provision of methods by which such keys might be
      associated with a process so that network filesystems, encryption
      support and the like can find them.

      Furthermore, a special type of key is available that acts as keyring:
      a searchable sequence of keys. Each process is equipped with access
      to five standard keyrings: UID-specific, GID-specific, session,
      process and thread.

      If you are unsure as to whether this is required, answer N.

config TRUSTED_KEYS
    tristate "TRUSTED KEYS"
    depends on KEYS && TCG_TPM
    select CRYPTO
    select CRYPTO_HMAC
    select CRYPTO_SHA1
    help
      This option provides support for creating, sealing, and unsealing
      keys in the kernel. Trusted keys are random number symmetric keys,
      generated and RSA-sealed by the TPM. The TPM only unseals the keys,
      if the boot PCRs and other criteria match.  Userspace will only ever
      see encrypted blobs.

      If you are unsure as to whether this is required, answer N.

config ENCRYPTED_KEYS
    tristate "ENCRYPTED KEYS"
    depends on KEYS && TRUSTED_KEYS
    select CRYPTO_AES
    select CRYPTO_CBC
    select CRYPTO_SHA256
    select CRYPTO_RNG
    help
      This option provides support for create/encrypting/decrypting keys
      in the kernel.  Encrypted keys are kernel generated random numbers,
      which are encrypted/decrypted with a 'master' symmetric key. The
      'master' key can be either a trusted-key or user-key type.
      Userspace only ever sees/stores encrypted blobs.

      If you are unsure as to whether this is required, answer N.

config KEYS_DEBUG_PROC_KEYS
    bool "Enable the /proc/keys file by which keys may be viewed"
    depends on KEYS
    help
      This option turns on support for the /proc/keys file - through which
      can be listed all the keys on the system that are viewable by the
      reading process.

      The only keys included in the list are those that grant View
      permission to the reading process whether or not it possesses them.
      Note that LSM security checks are still performed, and may further
      filter out keys that the current process is not authorised to view.

      Only key attributes are listed here; key payloads are not included in
      the resulting table.

      If you are unsure as to whether this is required, answer N.

config SECURITY_DMESG_RESTRICT
    bool "Restrict unprivileged access to the kernel syslog"
    default n
    help
      This enforces restrictions on unprivileged users reading the kernel
      syslog via dmesg(8).

      If this option is not selected, no restrictions will be enforced
      unless the dmesg_restrict sysctl is explicitly set to (1).

      If you are unsure how to answer this question, answer N.

config SECURITY
    bool "Enable different security models"
    depends on SYSFS
    help
      This allows you to choose different security modules to be
      configured into your kernel.

      If this option is not selected, the default Linux security
      model will be used.

      If you are unsure how to answer this question, answer N.

config SECURITYFS
    bool "Enable the securityfs filesystem"
    help
      This will build the securityfs filesystem.  It is currently used by
      the TPM bios character driver and IMA, an integrity provider.  It is
      not used by SELinux or SMACK.

      If you are unsure how to answer this question, answer N.

config SECURITY_NETWORK
    bool "Socket and Networking Security Hooks"
    depends on SECURITY
    help
      This enables the socket and networking security hooks.
      If enabled, a security module can use these hooks to
      implement socket and networking access controls.
      If you are unsure how to answer this question, answer N.

config SECURITY_NETWORK_XFRM
    bool "XFRM (IPSec) Networking Security Hooks"
    depends on XFRM && SECURITY_NETWORK
    help
      This enables the XFRM (IPSec) networking security hooks.
      If enabled, a security module can use these hooks to
      implement per-packet access controls based on labels
      derived from IPSec policy.  Non-IPSec communications are
      designated as unlabelled, and only sockets authorized
      to communicate unlabelled data can send without using
      IPSec.
      If you are unsure how to answer this question, answer N.

config SECURITY_PATH
    bool "Security hooks for pathname based access control"
    depends on SECURITY
    help
      This enables the security hooks for pathname based access control.
      If enabled, a security module can use these hooks to
      implement pathname based access controls.
      If you are unsure how to answer this question, answer N.

config INTEL_TXT
    bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
    depends on HAVE_INTEL_TXT
    help
      This option enables support for booting the kernel with the
      Trusted Boot (tboot) module. This will utilize
      Intel(R) Trusted Execution Technology to perform a measured launch
      of the kernel. If the system does not support Intel(R) TXT, this
      will have no effect.

      Intel TXT will provide higher assurance of system configuration and
      initial state as well as data reset protection.  This is used to
      create a robust initial kernel measurement and verification, which
      helps to ensure that kernel security mechanisms are functioning
      correctly. This level of protection requires a root of trust outside
      of the kernel itself.

      Intel TXT also helps solve real end user concerns about having
      confidence that their hardware is running the VMM or kernel that
      it was configured with, especially since they may be responsible for
      providing such assurances to VMs and services running on it.

      See <http://www.intel.com/technology/security/> for more information
      about Intel(R) TXT.
      See <http://tboot.sourceforge.net> for more information about tboot.
      See Documentation/intel_txt.txt for a description of how to enable
      Intel TXT support in a kernel boot.

      If you are unsure as to whether this is required, answer N.

config LSM_MMAP_MIN_ADDR
    int "Low address space for LSM to protect from user allocation"
    depends on SECURITY && SECURITY_SELINUX
    default 65536
    help
      This is the portion of low virtual memory which should be protected
      from userspace allocation.  Keeping a user from writing to low pages
      can help reduce the impact of kernel NULL pointer bugs.

      For most ia64, ppc64 and x86 users with lots of address space
      a value of 65536 is reasonable and should cause no problems.
      On arm and other archs it should not be higher than 32768.
      Programs which use vm86 functionality or have some need to map
      this low address space will need the permission specific to the
      systems running LSM.

source security/selinux/Kconfig
source security/smack/Kconfig
source security/tomoyo/Kconfig
source security/apparmor/Kconfig

source security/integrity/ima/Kconfig
source security/ptlsm/Kconfig

choice
    prompt "Default security module"
    default DEFAULT_SECURITY_SELINUX if SECURITY_SELINUX
    default DEFAULT_SECURITY_SMACK if SECURITY_SMACK
    default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO
    default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR
    default DEFAULT_SECURITY_DAC

    help
      Select the security module that will be used by default if the
      kernel parameter security= is not specified.

    config DEFAULT_SECURITY_SELINUX
        bool "SELinux" if SECURITY_SELINUX=y

    config DEFAULT_SECURITY_SMACK
        bool "Simplified Mandatory Access Control" if SECURITY_SMACK=y

    config DEFAULT_SECURITY_TOMOYO
        bool "TOMOYO" if SECURITY_TOMOYO=y

    config DEFAULT_SECURITY_APPARMOR
        bool "AppArmor" if SECURITY_APPARMOR=y

    config DEFAULT_SECURITY_DAC
        bool "Unix Discretionary Access Controls"

endchoice

config DEFAULT_SECURITY
    string
    default "selinux" if DEFAULT_SECURITY_SELINUX
    default "smack" if DEFAULT_SECURITY_SMACK
    default "tomoyo" if DEFAULT_SECURITY_TOMOYO
    default "apparmor" if DEFAULT_SECURITY_APPARMOR
    default "" if DEFAULT_SECURITY_DAC

endmenu