Re: [PATCH] Realtime LSM updated patch 2.6.10-rc2-mm3-rt2

[Jack O'Quin]

To save time, here is the original announcement...

  http://lkml.org/lkml/2004/11/9/288

Lee Revell <rlrevell@xxxxxxxxxxx> writes:

> On Tue, 2004-11-09 at 16:39 -0600, Jack O'Quin wrote:
> > +#include <linux/module.h>
> > +#include <linux/security.h>
> 
> These seem to be the only two includes that are needed.

This updated patch removes the unnecessary includes.  There are no
other changes.  It was applied against 2.6.10-rc2-mm3.

Signed-Off-By: Jack O'Quin <joq@xxxxxx>

diff -ruN -X /home/joq/bin/kdiff.exclude linux-2.6.10-rc2-mm3/Documentation/realtime-lsm.txt linux-2.6.10-rc2-mm3-rt2/Documentation/realtime-lsm.txt
--- linux-2.6.10-rc2-mm3/Documentation/realtime-lsm.txt	Wed Dec 31 18:00:00 1969
+++ linux-2.6.10-rc2-mm3-rt2/Documentation/realtime-lsm.txt	Wed Nov 24 09:58:29 2004
@@ -0,0 +1,39 @@
+
+		    Realtime Linux Security Module
+
+
+This Linux Security Module (LSM) enables realtime capabilities.  It
+was written by Torben Hohn and Jack O'Quin, under the provisions of
+the GPL (see the COPYING file).  We make no warranty concerning the
+safety, security or even stability of your system when using it.  But,
+we will fix problems if you report them.
+
+Once the LSM has been installed and the kernel for which it was built
+is running, the root user can load it and pass parameters as follows:
+
+  # modprobe realtime any=1
+
+  Any program can request realtime privileges.  This allows any local
+  user to crash the system by hogging the CPU in a tight loop or
+  locking down too much memory.  But, it is simple to administer.  :-)
+
+  # modprobe realtime gid=29
+
+  All users belonging to group 29 and programs that are setgid to that
+  group have realtime privileges.  Use any group number you like.  A
+  `gid' of -1 disables group access.
+
+  # modprobe realtime mlock=0
+
+  Grants realtime scheduling privileges without the ability to lock
+  memory using mlock() or mlockall() system calls.  This option can be
+  used in conjunction with any of the other options.
+
+After the module is loaded, its parameters can be changed dynamically
+via sysfs.
+
+  # echo 1  > /sys/module/realtime/parameters/any
+  # echo 29 > /sys/module/realtime/parameters/gid
+  # echo 1  > /sys/module/realtime/parameters/mlock
+
+Jack O'Quin, joq@xxxxxx
diff -ruN -X /home/joq/bin/kdiff.exclude linux-2.6.10-rc2-mm3/security/Kconfig linux-2.6.10-rc2-mm3-rt2/security/Kconfig
--- linux-2.6.10-rc2-mm3/security/Kconfig	Wed Nov 24 09:35:44 2004
+++ linux-2.6.10-rc2-mm3-rt2/security/Kconfig	Wed Nov 24 09:58:29 2004
@@ -84,6 +84,17 @@
 
 	  If you are unsure how to answer this question, answer N.
 
+config SECURITY_REALTIME
+	tristate "Realtime Capabilities"
+	depends on SECURITY && SECURITY_CAPABILITIES!=y
+	default n
+	help
+	  This module selectively grants realtime privileges
+	  controlled by parameters set at load time or via files in
+	  /sys/module/realtime/parameters.
+
+	  If you are unsure how to answer this question, answer N.
+
 source security/selinux/Kconfig
 
 endmenu
diff -ruN -X /home/joq/bin/kdiff.exclude linux-2.6.10-rc2-mm3/security/Makefile linux-2.6.10-rc2-mm3-rt2/security/Makefile
--- linux-2.6.10-rc2-mm3/security/Makefile	Wed Nov 24 09:35:44 2004
+++ linux-2.6.10-rc2-mm3-rt2/security/Makefile	Wed Nov 24 09:58:29 2004
@@ -17,3 +17,4 @@
 obj-$(CONFIG_SECURITY_CAPABILITIES)	+= commoncap.o capability.o
 obj-$(CONFIG_SECURITY_ROOTPLUG)		+= commoncap.o root_plug.o
 obj-$(CONFIG_SECURITY_SECLVL)		+= seclvl.o
+obj-$(CONFIG_SECURITY_REALTIME)		+= commoncap.o realtime.o
diff -ruN -X /home/joq/bin/kdiff.exclude linux-2.6.10-rc2-mm3/security/realtime.c linux-2.6.10-rc2-mm3-rt2/security/realtime.c
--- linux-2.6.10-rc2-mm3/security/realtime.c	Wed Dec 31 18:00:00 1969
+++ linux-2.6.10-rc2-mm3-rt2/security/realtime.c	Wed Nov 24 09:59:01 2004
@@ -0,0 +1,147 @@
+/*
+ * Realtime Capabilities Linux Security Module
+ *
+ *  Copyright (C) 2003 Torben Hohn
+ *  Copyright (C) 2003, 2004 Jack O'Quin
+ *
+ *	This program is free software; you can redistribute it and/or modify
+ *	it under the terms of the GNU General Public License as published by
+ *	the Free Software Foundation; either version 2 of the License, or
+ *	(at your option) any later version.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/security.h>
+
+#define RT_LSM "Realtime LSM "		/* syslog module name prefix */
+#define RT_ERR "Realtime: "		/* syslog error message prefix */
+
+#include <linux/vermagic.h>
+MODULE_INFO(vermagic,VERMAGIC_STRING);
+
+/* module parameters
+ *
+ *  These values could change at any time due to some process writing
+ *  a new value in /sys/module/realtime/parameters.  This is OK,
+ *  because each is referenced only once in each function call.
+ *  Nothing depends on parameters having the same value every time.
+ */
+
+/* if TRUE, any process is realtime */
+static int rt_any;
+module_param_named(any, rt_any, int, 0644);
+MODULE_PARM_DESC(any, " grant realtime privileges to any process.");
+
+/* realtime group id, or NO_GROUP */
+static int rt_gid = -1;
+module_param_named(gid, rt_gid, int, 0644);
+MODULE_PARM_DESC(gid, " the group ID with access to realtime privileges.");
+
+/* enable mlock() privileges */
+static int rt_mlock = 1;
+module_param_named(mlock, rt_mlock, int, 0644);
+MODULE_PARM_DESC(mlock, " enable memory locking privileges.");
+
+/* helper function for testing group membership */
+static inline int gid_ok(int gid)
+{
+	if (gid == -1)
+		return 0;
+
+	if (gid == current->gid)
+		return 1;
+
+	return in_egroup_p(gid);
+}
+
+static void realtime_bprm_apply_creds(struct linux_binprm *bprm, int unsafe)
+{
+	cap_bprm_apply_creds(bprm, unsafe);
+
+	/*  If a non-zero `any' parameter was specified, we grant
+	 *  realtime privileges to every process.  If the `gid'
+	 *  parameter was specified and it matches the group id of the
+	 *  executable, of the current process or any supplementary
+	 *  groups, we grant realtime capabilites.
+	 */
+
+	if (rt_any || gid_ok(rt_gid)) {
+		cap_raise(current->cap_effective, CAP_SYS_NICE);
+		if (rt_mlock) {
+			cap_raise(current->cap_effective, CAP_IPC_LOCK);
+			cap_raise(current->cap_effective, CAP_SYS_RESOURCE);
+		}
+	}
+}
+
+static struct security_operations capability_ops = {
+	.ptrace =			cap_ptrace,
+	.capget =			cap_capget,
+	.capset_check =			cap_capset_check,
+	.capset_set =			cap_capset_set,
+	.capable =			cap_capable,
+	.netlink_send =			cap_netlink_send,
+	.netlink_recv =			cap_netlink_recv,
+	.bprm_apply_creds =		realtime_bprm_apply_creds,
+	.bprm_set_security =		cap_bprm_set_security,
+	.bprm_secureexec =		cap_bprm_secureexec,
+	.task_post_setuid =		cap_task_post_setuid,
+	.task_reparent_to_init =	cap_task_reparent_to_init,
+	.syslog =                       cap_syslog,
+	.vm_enough_memory =             cap_vm_enough_memory,
+};
+
+#define MY_NAME __stringify(KBUILD_MODNAME)
+
+static int secondary;	/* flag to keep track of how we were registered */
+
+static int __init realtime_init(void)
+{
+	/* register ourselves with the security framework */
+	if (register_security(&capability_ops)) {
+
+		/* try registering with primary module */
+		if (mod_reg_security(MY_NAME, &capability_ops)) {
+			printk(KERN_INFO RT_ERR "Failure registering "
+			       "capabilities with primary security module.\n");
+			printk(KERN_INFO RT_ERR "Is kernel configured "
+			       "with CONFIG_SECURITY_CAPABILITIES=m?\n");
+			return -EINVAL;
+		}
+		secondary = 1;
+	}
+
+	if (rt_any)
+		printk(KERN_INFO RT_LSM
+		       "initialized (all groups, mlock=%d)\n", rt_mlock);
+	else if (rt_gid == -1)
+		printk(KERN_INFO RT_LSM
+		       "initialized (no groups, mlock=%d)\n", rt_mlock);
+	else
+		printk(KERN_INFO RT_LSM
+		       "initialized (group %d, mlock=%d)\n", rt_gid, rt_mlock);
+		
+	return 0;
+}
+
+static void __exit realtime_exit(void)
+{
+	/* remove ourselves from the security framework */
+	if (secondary) {
+		if (mod_unreg_security(MY_NAME, &capability_ops))
+			printk(KERN_INFO RT_ERR "Failure unregistering "
+				"capabilities with primary module.\n");
+
+	} else if (unregister_security(&capability_ops)) {
+		printk(KERN_INFO RT_ERR
+		       "Failure unregistering capabilities with the kernel\n");
+	}
+	printk(KERN_INFO "Realtime Capability LSM exiting\n");
+}
+
+late_initcall(realtime_init);
+module_exit(realtime_exit);
+
+MODULE_DESCRIPTION("Realtime Capabilities Security Module");
+MODULE_LICENSE("GPL");

-- 
  joq
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