[PATCH] LSM: remove BSD secure level security module

This code has suffered from broken core design and lack of developer
attention.  Broken security modules are too dangerous to leave around.  It
is time to remove this one.
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Davi Arnaut <davi.arnaut@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/seclvl.txt

-BSD Secure Levels Linux Security Module
-Michael A. Halcrow <mike@halcrow.us>
-
-
-Introduction
-
-Under the BSD Secure Levels security model, sets of policies are
-associated with levels. Levels range from -1 to 2, with -1 being the
-weakest and 2 being the strongest. These security policies are
-enforced at the kernel level, so not even the superuser is able to
-disable or circumvent them. This hardens the machine against attackers
-who gain root access to the system.
-
-
-Levels and Policies
-
-Level -1 (Permanently Insecure):
- - Cannot increase the secure level
-
-Level 0 (Insecure):
- - Cannot ptrace the init process
-
-Level 1 (Default):
- - /dev/mem and /dev/kmem are read-only
- - IMMUTABLE and APPEND extended attributes, if set, may not be unset
- - Cannot load or unload kernel modules
- - Cannot write directly to a mounted block device
- - Cannot perform raw I/O operations
- - Cannot perform network administrative tasks
- - Cannot setuid any file
-
-Level 2 (Secure):
- - Cannot decrement the system time
- - Cannot write to any block device, whether mounted or not
- - Cannot unmount any mounted filesystems
-
-
-Compilation
-
-To compile the BSD Secure Levels LSM, seclvl.ko, enable the
-SECURITY_SECLVL configuration option.  This is found under Security
-options -> BSD Secure Levels in the kernel configuration menu.
-
-
-Basic Usage
-
-Once the machine is in a running state, with all the necessary modules
-loaded and all the filesystems mounted, you can load the seclvl.ko
-module:
-
-# insmod seclvl.ko
-
-The module defaults to secure level 1, except when compiled directly
-into the kernel, in which case it defaults to secure level 0. To raise
-the secure level to 2, the administrator writes ``2'' to the
-seclvl/seclvl file under the sysfs mount point (assumed to be /sys in
-these examples):
-
-# echo -n "2" > /sys/seclvl/seclvl
-
-Alternatively, you can initialize the module at secure level 2 with
-the initlvl module parameter:
-
-# insmod seclvl.ko initlvl=2
-
-At this point, it is impossible to remove the module or reduce the
-secure level.  If the administrator wishes to have the option of doing
-so, he must provide a module parameter, sha1_passwd, that specifies
-the SHA1 hash of the password that can be used to reduce the secure
-level to 0.
-
-To generate this SHA1 hash, the administrator can use OpenSSL:
-
-# echo -n "boogabooga" | openssl sha1
-abeda4e0f33defa51741217592bf595efb8d289c
-
-In order to use password-instigated secure level reduction, the SHA1
-crypto module must be loaded or compiled into the kernel:
-
-# insmod sha1.ko
-
-The administrator can then insmod the seclvl module, including the
-SHA1 hash of the password:
-
-# insmod seclvl.ko
-         sha1_passwd=abeda4e0f33defa51741217592bf595efb8d289c
-
-To reduce the secure level, write the password to seclvl/passwd under
-your sysfs mount point:
-
-# echo -n "boogabooga" > /sys/seclvl/passwd
-
-The September 2004 edition of Sys Admin Magazine has an article about
-the BSD Secure Levels LSM.  I encourage you to refer to that article
-for a more in-depth treatment of this security module:
-
-http://www.samag.com/documents/s=9304/sam0409a/0409a.htm

security/Kconfig

@@ -93,18 +93,6 @@ config SECURITY_ROOTPLUG
 	  
 	  If you are unsure how to answer this question, answer N.
 
-config SECURITY_SECLVL
-	tristate "BSD Secure Levels"
-	depends on SECURITY
-	select CRYPTO
-	select CRYPTO_SHA1
-	help
-	  Implements BSD Secure Levels as an LSM.  See
-	  <file:Documentation/seclvl.txt> for instructions on how to use this
-	  module.
-
-	  If you are unsure how to answer this question, answer N.
-
 source security/selinux/Kconfig
 
 endmenu

security/Makefile

@@ -16,4 +16,3 @@ obj-$(CONFIG_SECURITY)			+= security.o dummy.o inode.o
 obj-$(CONFIG_SECURITY_SELINUX)		+= selinux/built-in.o
 obj-$(CONFIG_SECURITY_CAPABILITIES)	+= commoncap.o capability.o
 obj-$(CONFIG_SECURITY_ROOTPLUG)		+= commoncap.o root_plug.o
-obj-$(CONFIG_SECURITY_SECLVL)		+= seclvl.o