linux/security/apparmor/Kconfig
Dimitri John Ledkov e44a4dc4b3 apparmor: switch SECURITY_APPARMOR_HASH from sha1 to sha256
sha1 is insecure and has colisions, thus it is not useful for even
lightweight policy hash checks. Switch to sha256, which on modern
hardware is fast enough.

Separately as per NIST Policy on Hash Functions, sha1 usage must be
withdrawn by 2030. This config option currently is one of many that
holds up sha1 usage.

Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2023-11-19 00:47:56 -08:00

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# SPDX-License-Identifier: GPL-2.0-only
config SECURITY_APPARMOR
bool "AppArmor support"
depends on SECURITY && NET
select AUDIT
select SECURITY_PATH
select SECURITYFS
select SECURITY_NETWORK
default n
help
This enables the AppArmor security module.
Required userspace tools (if they are not included in your
distribution) and further information may be found at
http://apparmor.wiki.kernel.org
If you are unsure how to answer this question, answer N.
config SECURITY_APPARMOR_DEBUG
bool "Build AppArmor with debug code"
depends on SECURITY_APPARMOR
default n
help
Build apparmor with debugging logic in apparmor. Not all
debugging logic will necessarily be enabled. A submenu will
provide fine grained control of the debug options that are
available.
config SECURITY_APPARMOR_DEBUG_ASSERTS
bool "Build AppArmor with debugging asserts"
depends on SECURITY_APPARMOR_DEBUG
default y
help
Enable code assertions made with AA_BUG. These are primarily
function entry preconditions but also exist at other key
points. If the assert is triggered it will trigger a WARN
message.
config SECURITY_APPARMOR_DEBUG_MESSAGES
bool "Debug messages enabled by default"
depends on SECURITY_APPARMOR_DEBUG
default n
help
Set the default value of the apparmor.debug kernel parameter.
When enabled, various debug messages will be logged to
the kernel message buffer.
config SECURITY_APPARMOR_INTROSPECT_POLICY
bool "Allow loaded policy to be introspected"
depends on SECURITY_APPARMOR
default y
help
This option selects whether introspection of loaded policy
is available to userspace via the apparmor filesystem. This
adds to kernel memory usage. It is required for introspection
of loaded policy, and check point and restore support. It
can be disabled for embedded systems where reducing memory and
cpu is paramount.
config SECURITY_APPARMOR_HASH
bool "Enable introspection of sha256 hashes for loaded profiles"
depends on SECURITY_APPARMOR_INTROSPECT_POLICY
select CRYPTO
select CRYPTO_SHA256
default y
help
This option selects whether introspection of loaded policy
hashes is available to userspace via the apparmor
filesystem. This option provides a light weight means of
checking loaded policy. This option adds to policy load
time and can be disabled for small embedded systems.
config SECURITY_APPARMOR_HASH_DEFAULT
bool "Enable policy hash introspection by default"
depends on SECURITY_APPARMOR_HASH
default y
help
This option selects whether sha256 hashing of loaded policy
is enabled by default. The generation of sha256 hashes for
loaded policy provide system administrators a quick way to
verify that policy in the kernel matches what is expected,
however it can slow down policy load on some devices. In
these cases policy hashing can be disabled by default and
enabled only if needed.
config SECURITY_APPARMOR_EXPORT_BINARY
bool "Allow exporting the raw binary policy"
depends on SECURITY_APPARMOR_INTROSPECT_POLICY
select ZSTD_COMPRESS
select ZSTD_DECOMPRESS
default y
help
This option allows reading back binary policy as it was loaded.
It increases the amount of kernel memory needed by policy and
also increases policy load time. This option is required for
checkpoint and restore support, and debugging of loaded policy.
config SECURITY_APPARMOR_PARANOID_LOAD
bool "Perform full verification of loaded policy"
depends on SECURITY_APPARMOR
default y
help
This options allows controlling whether apparmor does a full
verification of loaded policy. This should not be disabled
except for embedded systems where the image is read only,
includes policy, and has some form of integrity check.
Disabling the check will speed up policy loads.
config SECURITY_APPARMOR_KUNIT_TEST
tristate "Build KUnit tests for policy_unpack.c" if !KUNIT_ALL_TESTS
depends on KUNIT && SECURITY_APPARMOR
default KUNIT_ALL_TESTS
help
This builds the AppArmor KUnit tests.
KUnit tests run during boot and output the results to the debug log
in TAP format (https://testanything.org/). Only useful for kernel devs
running KUnit test harness and are not for inclusion into a
production build.
For more information on KUnit and unit tests in general please refer
to the KUnit documentation in Documentation/dev-tools/kunit/.
If unsure, say N.