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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /security/root_plug.c
downloadlinux-2.6.38-lt-ux500-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'security/root_plug.c')
-rw-r--r--security/root_plug.c142
1 files changed, 142 insertions, 0 deletions
diff --git a/security/root_plug.c b/security/root_plug.c
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+++ b/security/root_plug.c
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+/*
+ * Root Plug sample LSM module
+ *
+ * Originally written for a Linux Journal.
+ *
+ * Copyright (C) 2002 Greg Kroah-Hartman <greg@kroah.com>
+ *
+ * Prevents any programs running with egid == 0 if a specific USB device
+ * is not present in the system. Yes, it can be gotten around, but is a
+ * nice starting point for people to play with, and learn the LSM
+ * interface.
+ *
+ * If you want to turn this into something with a semblance of security,
+ * you need to hook the task_* functions also.
+ *
+ * See http://www.linuxjournal.com/article.php?sid=6279 for more information
+ * about this code.
+ *
+ * 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, version 2 of the
+ * License.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/security.h>
+#include <linux/usb.h>
+
+/* flag to keep track of how we were registered */
+static int secondary;
+
+/* default is a generic type of usb to serial converter */
+static int vendor_id = 0x0557;
+static int product_id = 0x2008;
+
+module_param(vendor_id, uint, 0400);
+MODULE_PARM_DESC(vendor_id, "USB Vendor ID of device to look for");
+
+module_param(product_id, uint, 0400);
+MODULE_PARM_DESC(product_id, "USB Product ID of device to look for");
+
+/* should we print out debug messages */
+static int debug = 0;
+
+module_param(debug, bool, 0600);
+MODULE_PARM_DESC(debug, "Debug enabled or not");
+
+#if defined(CONFIG_SECURITY_ROOTPLUG_MODULE)
+#define MY_NAME THIS_MODULE->name
+#else
+#define MY_NAME "root_plug"
+#endif
+
+#define root_dbg(fmt, arg...) \
+ do { \
+ if (debug) \
+ printk(KERN_DEBUG "%s: %s: " fmt , \
+ MY_NAME , __FUNCTION__ , \
+ ## arg); \
+ } while (0)
+
+static int rootplug_bprm_check_security (struct linux_binprm *bprm)
+{
+ struct usb_device *dev;
+
+ root_dbg("file %s, e_uid = %d, e_gid = %d\n",
+ bprm->filename, bprm->e_uid, bprm->e_gid);
+
+ if (bprm->e_gid == 0) {
+ dev = usb_find_device(vendor_id, product_id);
+ if (!dev) {
+ root_dbg("e_gid = 0, and device not found, "
+ "task not allowed to run...\n");
+ return -EPERM;
+ }
+ usb_put_dev(dev);
+ }
+
+ return 0;
+}
+
+static struct security_operations rootplug_security_ops = {
+ /* Use the capability functions for some of the hooks */
+ .ptrace = cap_ptrace,
+ .capget = cap_capget,
+ .capset_check = cap_capset_check,
+ .capset_set = cap_capset_set,
+ .capable = cap_capable,
+
+ .bprm_apply_creds = cap_bprm_apply_creds,
+ .bprm_set_security = cap_bprm_set_security,
+
+ .task_post_setuid = cap_task_post_setuid,
+ .task_reparent_to_init = cap_task_reparent_to_init,
+
+ .bprm_check_security = rootplug_bprm_check_security,
+};
+
+static int __init rootplug_init (void)
+{
+ /* register ourselves with the security framework */
+ if (register_security (&rootplug_security_ops)) {
+ printk (KERN_INFO
+ "Failure registering Root Plug module with the kernel\n");
+ /* try registering with primary module */
+ if (mod_reg_security (MY_NAME, &rootplug_security_ops)) {
+ printk (KERN_INFO "Failure registering Root Plug "
+ " module with primary security module.\n");
+ return -EINVAL;
+ }
+ secondary = 1;
+ }
+ printk (KERN_INFO "Root Plug module initialized, "
+ "vendor_id = %4.4x, product id = %4.4x\n", vendor_id, product_id);
+ return 0;
+}
+
+static void __exit rootplug_exit (void)
+{
+ /* remove ourselves from the security framework */
+ if (secondary) {
+ if (mod_unreg_security (MY_NAME, &rootplug_security_ops))
+ printk (KERN_INFO "Failure unregistering Root Plug "
+ " module with primary module.\n");
+ } else {
+ if (unregister_security (&rootplug_security_ops)) {
+ printk (KERN_INFO "Failure unregistering Root Plug "
+ "module with the kernel\n");
+ }
+ }
+ printk (KERN_INFO "Root Plug module removed\n");
+}
+
+security_initcall (rootplug_init);
+module_exit (rootplug_exit);
+
+MODULE_DESCRIPTION("Root Plug sample LSM module, written for Linux Journal article");
+MODULE_LICENSE("GPL");
+