linux/security/Kconfig
Linus Torvalds 6040e57658 Make the hardened user-copy code depend on having a hardened allocator
The kernel test robot reported a usercopy failure in the new hardened
sanity checks, due to a page-crossing copy of the FPU state into the
task structure.

This happened because the kernel test robot was testing with SLOB, which
doesn't actually do the required book-keeping for slab allocations, and
as a result the hardening code didn't realize that the task struct
allocation was one single allocation - and the sanity checks fail.

Since SLOB doesn't even claim to support hardening (and you really
shouldn't use it), the straightforward solution is to just make the
usercopy hardening code depend on the allocator supporting it.

Reported-by: kernel test robot <xiaolong.ye@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-19 12:47:01 -07:00

198 lines
6.7 KiB
Plaintext

#
# Security configuration
#
menu "Security options"
source security/keys/Kconfig
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
depends on MULTIUSER
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 32768 if ARM || (ARM64 && COMPAT)
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.
config HAVE_HARDENED_USERCOPY_ALLOCATOR
bool
help
The heap allocator implements __check_heap_object() for
validating memory ranges against heap object sizes in
support of CONFIG_HARDENED_USERCOPY.
config HAVE_ARCH_HARDENED_USERCOPY
bool
help
The architecture supports CONFIG_HARDENED_USERCOPY by
calling check_object_size() just before performing the
userspace copies in the low level implementation of
copy_to_user() and copy_from_user().
config HARDENED_USERCOPY
bool "Harden memory copies between kernel and userspace"
depends on HAVE_ARCH_HARDENED_USERCOPY
depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
select BUG
help
This option checks for obviously wrong memory regions when
copying memory to/from the kernel (via copy_to_user() and
copy_from_user() functions) by rejecting memory ranges that
are larger than the specified heap object, span multiple
separately allocates pages, are not on the process stack,
or are part of the kernel text. This kills entire classes
of heap overflow exploits and similar kernel memory exposures.
source security/selinux/Kconfig
source security/smack/Kconfig
source security/tomoyo/Kconfig
source security/apparmor/Kconfig
source security/loadpin/Kconfig
source security/yama/Kconfig
source security/integrity/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