[PATCH security-next v3 18/29] LSM: Introduce lsm.enable= and lsm.disable=
From: Kees Cook <hidden>
Date: 2018-09-25 00:25:54
Also in:
linux-arch, linux-doc, lkml
Subsystem:
documentation, security subsystem, the rest · Maintainers:
Jonathan Corbet, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
This introduces the "lsm.enable=..." and "lsm.disable=..." boot parameters
which each can contain a comma-separated list of LSMs to enable or
disable, respectively. The string "all" matches all LSMs.
This has very similar functionality to the existing per-LSM enable
handling ("apparmor.enabled=...", etc), but provides a centralized
place to perform the changes. These parameters take precedent over any
LSM-specific boot parameters.
Disabling an LSM means it will not be considered when performing
initializations. Enabling an LSM means either undoing a previous
LSM-specific boot parameter disabling or a undoing a default-disabled
CONFIG setting.
For example: "lsm.disable=apparmor apparmor.enabled=1" will result in
AppArmor being disabled. "selinux.enabled=0 lsm.enable=selinux" will
result in SELinux being enabled.
Signed-off-by: Kees Cook <redacted>
---
.../admin-guide/kernel-parameters.txt | 12 ++++++++++
security/Kconfig | 4 +++-
security/security.c | 22 +++++++++++++++++++
3 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 32d323ee9218..67c90985d2b8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt@@ -2276,6 +2276,18 @@ lsm.debug [SECURITY] Enable LSM initialization debugging output. + lsm.disable=lsm1,...,lsmN + [SECURITY] Comma-separated list of LSMs to disable + at boot time. This overrides "lsm.enable=", + CONFIG_LSM_ENABLE, and any per-LSM CONFIGs and boot + parameters. + + lsm.enable=lsm1,...,lsmN + [SECURITY] Comma-separated list of LSMs to enable + at boot time. This overrides any omissions from + CONFIG_LSM_ENABLE, and any per-LSM CONFIGs and + boot parameters. + machvec= [IA-64] Force the use of a particular machine-vector (machvec) in a generic kernel. Example: machvec=hpzx1_swiotlb
diff --git a/security/Kconfig b/security/Kconfig
index 71306b046270..1a82a006cc62 100644
--- a/security/Kconfig
+++ b/security/Kconfig@@ -282,7 +282,9 @@ config LSM_ENABLE help A comma-separate list of LSMs to enable by default at boot. The default is "all", to enable all LSM modules at boot. Any LSMs - not listed here will be disabled by default. + not listed here will be disabled by default. This can be + changed with the "lsm.enable=" and "lsm.disable=" boot + parameters. endmenu
diff --git a/security/security.c b/security/security.c
index 7ecb9879a863..456a3f73bc36 100644
--- a/security/security.c
+++ b/security/security.c@@ -44,6 +44,8 @@ char *lsm_names; /* Boot-time LSM user choice */ static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] = CONFIG_DEFAULT_SECURITY; +static __initdata const char *chosen_lsm_enable; +static __initdata const char *chosen_lsm_disable; static __initconst const char * const builtin_lsm_enable = CONFIG_LSM_ENABLE;
@@ -185,6 +187,10 @@ static void __init prepare_lsm_enable(void) { /* Prepare defaults. */ parse_lsm_enable(builtin_lsm_enable, default_enabled, true); + + /* Process "lsm.enable=" and "lsm.disable=", if given. */ + parse_lsm_enable(chosen_lsm_enable, set_enabled, true); + parse_lsm_enable(chosen_lsm_disable, set_enabled, false); } /**
@@ -240,6 +246,22 @@ static int __init enable_debug(char *str) } __setup("lsm.debug", enable_debug); +/* Explicitly enable a list of LSMs. */ +static int __init enable_lsm(char *str) +{ + chosen_lsm_enable = str; + return 1; +} +__setup("lsm.enable=", enable_lsm); + +/* Explicitly disable a list of LSMs. */ +static int __init disable_lsm(char *str) +{ + chosen_lsm_disable = str; + return 1; +} +__setup("lsm.disable=", disable_lsm); + static bool match_last_lsm(const char *list, const char *lsm) { const char *last;
--
2.17.1