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diff -puN /dev/null Documentation/realtime-lsm.txt
--- /dev/null 2003-09-15 06:40:47.000000000 -0700
+++ 25-akpm/Documentation/realtime-lsm.txt 2005-02-06 00:32:52.000000000 -0800
@@ -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@joq.us
diff -puN security/Kconfig~rt-lsm security/Kconfig
--- 25/security/Kconfig~rt-lsm 2005-02-06 00:32:52.000000000 -0800
+++ 25-akpm/security/Kconfig 2005-02-06 00:32:52.000000000 -0800
@@ -85,6 +85,17 @@ config SECURITY_SECLVL
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 -puN security/Makefile~rt-lsm security/Makefile
--- 25/security/Makefile~rt-lsm 2005-02-06 00:32:52.000000000 -0800
+++ 25-akpm/security/Makefile 2005-02-06 00:32:52.000000000 -0800
@@ -17,3 +17,4 @@ obj-$(CONFIG_SECURITY_SELINUX) += selin
obj-$(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 -puN /dev/null security/realtime.c
--- /dev/null 2003-09-15 06:40:47.000000000 -0700
+++ 25-akpm/security/realtime.c 2005-02-06 00:32:52.000000000 -0800
@@ -0,0 +1,146 @@
+/*
+ * Realtime Capabilities Linux Security Module
+ *
+ * Copyright (C) 2003 Torben Hohn
+ * Copyright (C) 2003-2005 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);
+ }
+ }
+}
+
+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");
+}
+
+security_initcall(realtime_init);
+module_exit(realtime_exit);
+
+MODULE_DESCRIPTION("Realtime Capabilities Security Module");
+MODULE_LICENSE("GPL");
_
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