1 files changed, 747 insertions, 0 deletions

diff --git a/security/seclvl.c b/security/seclvl.c
new file mode 100644
index 000000000000..8a0ab0d7949e
--- /dev/null
+++ b/security/seclvl.c
@@ -0,0 +1,747 @@
+/**
+ * BSD Secure Levels LSM
+ *
+ * Maintainers:
+ *      Michael A. Halcrow <mike@halcrow.us>
+ *      Serge Hallyn <hallyn@cs.wm.edu>
+ *
+ * Copyright (c) 2001 WireX Communications, Inc <chris@wirex.com>
+ * Copyright (c) 2001 Greg Kroah-Hartman <greg@kroah.com>
+ * Copyright (c) 2002 International Business Machines <robb@austin.ibm.com>
+ *
+ *      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/config.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/security.h>
+#include <linux/netlink.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/capability.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/kobject.h>
+#include <linux/crypto.h>
+#include <asm/scatterlist.h>
+#include <linux/gfp.h>
+#include <linux/sysfs.h>
+
+#define SHA1_DIGEST_SIZE 20
+
+/**
+ * Module parameter that defines the initial secure level.
+ *
+ * When built as a module, it defaults to seclvl 1, which is the
+ * behavior of BSD secure levels.  Note that this default behavior
+ * wrecks havoc on a machine when the seclvl module is compiled into
+ * the kernel.  In that case, we default to seclvl 0.
+ */
+#ifdef CONFIG_SECURITY_SECLVL_MODULE
+static int initlvl = 1;
+#else
+static int initlvl;
+#endif
+module_param(initlvl, int, 0);
+MODULE_PARM_DESC(initlvl, "Initial secure level (defaults to 1)");
+
+/* Module parameter that defines the verbosity level */
+static int verbosity;
+module_param(verbosity, int, 0);
+MODULE_PARM_DESC(verbosity, "Initial verbosity level (0 or 1; defaults to "
+                 "0, which is Quiet)");
+
+/**
+ * Optional password which can be passed in to bring seclvl to 0
+ * (i.e., for halt/reboot).  Defaults to NULL (the passwd attribute
+ * file will not be registered in sysfs).
+ *
+ * This gets converted to its SHA1 hash when stored.  It's probably
+ * not a good idea to use this parameter when loading seclvl from a
+ * script; use sha1_passwd instead.
+ */
+
+#define MAX_PASSWD_SIZE 32
+static char passwd[MAX_PASSWD_SIZE];
+module_param_string(passwd, passwd, sizeof(passwd), 0);
+MODULE_PARM_DESC(passwd,
+                 "Plaintext of password that sets seclvl=0 when written to "
+                 "(sysfs mount point)/seclvl/passwd\n");
+
+/**
+ * SHA1 hashed version of the optional password which can be passed in
+ * to bring seclvl to 0 (i.e., for halt/reboot).  Must be in
+ * hexadecimal format (40 characters).  Defaults to NULL (the passwd
+ * attribute file will not be registered in sysfs).
+ *
+ * Use the sha1sum utility to generate the SHA1 hash of a password:
+ *
+ * echo -n "secret" | sha1sum
+ */
+#define MAX_SHA1_PASSWD 41
+static char sha1_passwd[MAX_SHA1_PASSWD];
+module_param_string(sha1_passwd, sha1_passwd, sizeof(sha1_passwd), 0);
+MODULE_PARM_DESC(sha1_passwd,
+                 "SHA1 hash (40 hexadecimal characters) of password that "
+                 "sets seclvl=0 when plaintext password is written to "
+                 "(sysfs mount point)/seclvl/passwd\n");
+
+static int hideHash = 1;
+module_param(hideHash, int, 0);
+MODULE_PARM_DESC(hideHash, "When set to 0, reading seclvl/passwd from sysfs "
+                 "will return the SHA1-hashed value of the password that "
+                 "lowers the secure level to 0.\n");
+
+#define MY_NAME "seclvl"
+
+/**
+ * This time-limits log writes to one per second.
+ */
+#define seclvl_printk(verb, type, fmt, arg...)                  \
+        do {                                                    \
+                if (verbosity >= verb) {                        \
+                        static unsigned long _prior;            \
+                        unsigned long _now = jiffies;           \
+                        if ((_now - _prior) > HZ) {             \
+                                printk(type "%s: %s: " fmt,     \
+                                        MY_NAME, __FUNCTION__ , \
+                                        ## arg);                \
+                                _prior = _now;                  \
+                        }                                       \
+                }                                               \
+        } while (0)
+
+/**
+ * kobject stuff
+ */
+
+struct subsystem seclvl_subsys;
+
+struct seclvl_obj {
+        char *name;
+        struct list_head slot_list;
+        struct kobject kobj;
+};
+
+/**
+ * There is a seclvl_attribute struct for each file in sysfs.
+ *
+ * In our case, we have one of these structs for "passwd" and another
+ * for "seclvl".
+ */
+struct seclvl_attribute {
+        struct attribute attr;
+        ssize_t(*show) (struct seclvl_obj *, char *);
+        ssize_t(*store) (struct seclvl_obj *, const char *, size_t);
+};
+
+/**
+ * When this function is called, one of the files in sysfs is being
+ * written to.  attribute->store is a function pointer to whatever the
+ * struct seclvl_attribute store function pointer points to.  It is
+ * unique for "passwd" and "seclvl".
+ */
+static ssize_t
+seclvl_attr_store(struct kobject *kobj,
+                  struct attribute *attr, const char *buf, size_t len)
+{
+        struct seclvl_obj *obj = container_of(kobj, struct seclvl_obj, kobj);
+        struct seclvl_attribute *attribute =
+            container_of(attr, struct seclvl_attribute, attr);
+        return (attribute->store ? attribute->store(obj, buf, len) : 0);
+}
+
+static ssize_t
+seclvl_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
+{
+        struct seclvl_obj *obj = container_of(kobj, struct seclvl_obj, kobj);
+        struct seclvl_attribute *attribute =
+            container_of(attr, struct seclvl_attribute, attr);
+        return (attribute->show ? attribute->show(obj, buf) : 0);
+}
+
+/**
+ * Callback function pointers for show and store
+ */
+static struct sysfs_ops seclvlfs_sysfs_ops = {
+        .show = seclvl_attr_show,
+        .store = seclvl_attr_store,
+};
+
+static struct kobj_type seclvl_ktype = {
+        .sysfs_ops = &seclvlfs_sysfs_ops
+};
+
+decl_subsys(seclvl, &seclvl_ktype, NULL);
+
+/**
+ * The actual security level.  Ranges between -1 and 2 inclusive.
+ */
+static int seclvl;
+
+/**
+ * flag to keep track of how we were registered
+ */
+static int secondary;
+
+/**
+ * Verifies that the requested secure level is valid, given the current
+ * secure level.
+ */
+static int seclvl_sanity(int reqlvl)
+{
+        if ((reqlvl < -1) || (reqlvl > 2)) {
+                seclvl_printk(1, KERN_WARNING, "Attempt to set seclvl out of "
+                              "range: [%d]\n", reqlvl);
+                return -EINVAL;
+        }
+        if ((seclvl == 0) && (reqlvl == -1))
+                return 0;
+        if (reqlvl < seclvl) {
+                seclvl_printk(1, KERN_WARNING, "Attempt to lower seclvl to "
+                              "[%d]\n", reqlvl);
+                return -EPERM;
+        }
+        return 0;
+}
+
+/**
+ * Called whenever the user reads the sysfs handle to this kernel
+ * object
+ */
+static ssize_t seclvl_read_file(struct seclvl_obj *obj, char *buff)
+{
+        return snprintf(buff, PAGE_SIZE, "%d\n", seclvl);
+}
+
+/**
+ * security level advancement rules:
+ *   Valid levels are -1 through 2, inclusive.
+ *   From -1, stuck.  [ in case compiled into kernel ]
+ *   From 0 or above, can only increment.
+ */
+static int do_seclvl_advance(int newlvl)
+{
+        if (newlvl <= seclvl) {
+                seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl "
+                              "[%d]\n", newlvl);
+                return -EINVAL;
+        }
+        if (newlvl > 2) {
+                seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl "
+                              "[%d]\n", newlvl);
+                return -EINVAL;
+        }
+        if (seclvl == -1) {
+                seclvl_printk(1, KERN_WARNING, "Not allowed to advance to "
+                              "seclvl [%d]\n", seclvl);
+                return -EPERM;
+        }
+        seclvl = newlvl;
+        return 0;
+}
+
+/**
+ * Called whenever the user writes to the sysfs handle to this kernel
+ * object (seclvl/seclvl).  It expects a single-digit number.
+ */
+static ssize_t
+seclvl_write_file(struct seclvl_obj *obj, const char *buff, size_t count)
+{
+        unsigned long val;
+        if (count > 2 || (count == 2 && buff[1] != '\n')) {
+                seclvl_printk(1, KERN_WARNING, "Invalid value passed to "
+                              "seclvl: [%s]\n", buff);
+                return -EINVAL;
+        }
+        val = buff[0] - 48;
+        if (seclvl_sanity(val)) {
+                seclvl_printk(1, KERN_WARNING, "Illegal secure level "
+                              "requested: [%d]\n", (int)val);
+                return -EPERM;
+        }
+        if (do_seclvl_advance(val)) {
+                seclvl_printk(0, KERN_ERR, "Failure advancing security level "
+                              "to %lu\n", val);
+        }
+        return count;
+}
+
+/* Generate sysfs_attr_seclvl */
+static struct seclvl_attribute sysfs_attr_seclvl =
+__ATTR(seclvl, (S_IFREG | S_IRUGO | S_IWUSR), seclvl_read_file,
+       seclvl_write_file);
+
+static unsigned char hashedPassword[SHA1_DIGEST_SIZE];
+
+/**
+ * Called whenever the user reads the sysfs passwd handle.
+ */
+static ssize_t seclvl_read_passwd(struct seclvl_obj *obj, char *buff)
+{
+        /* So just how good *is* your password? :-) */
+        char tmp[3];
+        int i = 0;
+        buff[0] = '\0';
+        if (hideHash) {
+                /* Security through obscurity */
+                return 0;
+        }
+        while (i < SHA1_DIGEST_SIZE) {
+                snprintf(tmp, 3, "%02x", hashedPassword[i]);
+                strncat(buff, tmp, 2);
+                i++;
+        }
+        strcat(buff, "\n");
+        return ((SHA1_DIGEST_SIZE * 2) + 1);
+}
+
+/**
+ * Converts a block of plaintext of into its SHA1 hashed value.
+ *
+ * It would be nice if crypto had a wrapper to do this for us linear
+ * people...
+ */
+static int
+plaintext_to_sha1(unsigned char *hash, const char *plaintext, int len)
+{
+        char *pgVirtAddr;
+        struct crypto_tfm *tfm;
+        struct scatterlist sg[1];
+        if (len > PAGE_SIZE) {
+                seclvl_printk(0, KERN_ERR, "Plaintext password too large (%d "
+                              "characters).  Largest possible is %lu "
+                              "bytes.\n", len, PAGE_SIZE);
+                return -ENOMEM;
+        }
+        tfm = crypto_alloc_tfm("sha1", 0);
+        if (tfm == NULL) {
+                seclvl_printk(0, KERN_ERR,
+                              "Failed to load transform for SHA1\n");
+                return -ENOSYS;
+        }
+        // Just get a new page; don't play around with page boundaries
+        // and scatterlists.
+        pgVirtAddr = (char *)__get_free_page(GFP_KERNEL);
+        sg[0].page = virt_to_page(pgVirtAddr);
+        sg[0].offset = 0;
+        sg[0].length = len;
+        strncpy(pgVirtAddr, plaintext, len);
+        crypto_digest_init(tfm);
+        crypto_digest_update(tfm, sg, 1);
+        crypto_digest_final(tfm, hash);
+        crypto_free_tfm(tfm);
+        free_page((unsigned long)pgVirtAddr);
+        return 0;
+}
+
+/**
+ * Called whenever the user writes to the sysfs passwd handle to this kernel
+ * object.  It hashes the password and compares the hashed results.
+ */
+static ssize_t
+seclvl_write_passwd(struct seclvl_obj *obj, const char *buff, size_t count)
+{
+        int i;
+        unsigned char tmp[SHA1_DIGEST_SIZE];
+        int rc;
+        int len;
+        if (!*passwd && !*sha1_passwd) {
+                seclvl_printk(0, KERN_ERR, "Attempt to password-unlock the "
+                              "seclvl module, but neither a plain text "
+                              "password nor a SHA1 hashed password was "
+                              "passed in as a module parameter!  This is a "
+                              "bug, since it should not be possible to be in "
+                              "this part of the module; please tell a "
+                              "maintainer about this event.\n");
+                return -EINVAL;
+        }
+        len = strlen(buff);
+        /* ``echo "secret" > seclvl/passwd'' includes a newline */
+        if (buff[len - 1] == '\n') {
+                len--;
+        }
+        /* Hash the password, then compare the hashed values */
+        if ((rc = plaintext_to_sha1(tmp, buff, len))) {
+                seclvl_printk(0, KERN_ERR, "Error hashing password: rc = "
+                              "[%d]\n", rc);
+                return rc;
+        }
+        for (i = 0; i < SHA1_DIGEST_SIZE; i++) {
+                if (hashedPassword[i] != tmp[i]) {
+                        return -EPERM;
+                }
+        }
+        seclvl_printk(0, KERN_INFO,
+                      "Password accepted; seclvl reduced to 0.\n");
+        seclvl = 0;
+        return count;
+}
+
+/* Generate sysfs_attr_passwd */
+static struct seclvl_attribute sysfs_attr_passwd =
+__ATTR(passwd, (S_IFREG | S_IRUGO | S_IWUSR), seclvl_read_passwd,
+       seclvl_write_passwd);
+
+/**
+ * Explicitely disallow ptrace'ing the init process.
+ */
+static int seclvl_ptrace(struct task_struct *parent, struct task_struct *child)
+{
+        if (seclvl >= 0) {
+                if (child->pid == 1) {
+                        seclvl_printk(1, KERN_WARNING, "Attempt to ptrace "
+                                      "the init process dissallowed in "
+                                      "secure level %d\n", seclvl);
+                        return -EPERM;
+                }
+        }
+        return 0;
+}
+
+/**
+ * Capability checks for seclvl.  The majority of the policy
+ * enforcement for seclvl takes place here.
+ */
+static int seclvl_capable(struct task_struct *tsk, int cap)
+{
+        /* init can do anything it wants */
+        if (tsk->pid == 1)
+                return 0;
+
+        switch (seclvl) {
+        case 2:
+                /* fall through */
+        case 1:
+                if (cap == CAP_LINUX_IMMUTABLE) {
+                        seclvl_printk(1, KERN_WARNING, "Attempt to modify "
+                                      "the IMMUTABLE and/or APPEND extended "
+                                      "attribute on a file with the IMMUTABLE "
+                                      "and/or APPEND extended attribute set "
+                                      "denied in seclvl [%d]\n", seclvl);
+                        return -EPERM;
+                } else if (cap == CAP_SYS_RAWIO) {      // Somewhat broad...
+                        seclvl_printk(1, KERN_WARNING, "Attempt to perform "
+                                      "raw I/O while in secure level [%d] "
+                                      "denied\n", seclvl);
+                        return -EPERM;
+                } else if (cap == CAP_NET_ADMIN) {
+                        seclvl_printk(1, KERN_WARNING, "Attempt to perform "
+                                      "network administrative task while "
+                                      "in secure level [%d] denied\n", seclvl);
+                        return -EPERM;
+                } else if (cap == CAP_SETUID) {
+                        seclvl_printk(1, KERN_WARNING, "Attempt to setuid "
+                                      "while in secure level [%d] denied\n",
+                                      seclvl);
+                        return -EPERM;
+                } else if (cap == CAP_SETGID) {
+                        seclvl_printk(1, KERN_WARNING, "Attempt to setgid "
+                                      "while in secure level [%d] denied\n",
+                                      seclvl);
+                } else if (cap == CAP_SYS_MODULE) {
+                        seclvl_printk(1, KERN_WARNING, "Attempt to perform "
+                                      "a module operation while in secure "
+                                      "level [%d] denied\n", seclvl);
+                        return -EPERM;
+                }
+                break;
+        default:
+                break;
+        }
+        /* from dummy.c */
+        if (cap_is_fs_cap(cap) ? tsk->fsuid == 0 : tsk->euid == 0)
+                return 0;       /* capability granted */
+        seclvl_printk(1, KERN_WARNING, "Capability denied\n");
+        return -EPERM;          /* capability denied */
+}
+
+/**
+ * Disallow reversing the clock in seclvl > 1
+ */
+static int seclvl_settime(struct timespec *tv, struct timezone *tz)
+{
+        struct timespec now;
+        if (seclvl > 1) {
+                now = current_kernel_time();
+                if (tv->tv_sec < now.tv_sec ||
+                    (tv->tv_sec == now.tv_sec && tv->tv_nsec < now.tv_nsec)) {
+                        seclvl_printk(1, KERN_WARNING, "Attempt to decrement "
+                                      "time in secure level %d denied: "
+                                      "current->pid = [%d], "
+                                      "current->group_leader->pid = [%d]\n",
+                                      seclvl, current->pid,
+                                      current->group_leader->pid);
+                        return -EPERM;
+                }               /* if attempt to decrement time */
+        }                       /* if seclvl > 1 */
+        return 0;
+}
+
+/* claim the blockdev to exclude mounters, release on file close */
+static int seclvl_bd_claim(struct inode *inode)
+{
+        int holder;
+        struct block_device *bdev = NULL;
+        dev_t dev = inode->i_rdev;
+        bdev = open_by_devnum(dev, FMODE_WRITE);
+        if (bdev) {
+                if (bd_claim(bdev, &holder)) {
+                        blkdev_put(bdev);
+                        return -EPERM;
+                }
+                /* claimed, mark it to release on close */
+                inode->i_security = current;
+        }
+        return 0;
+}
+
+/* release the blockdev if you claimed it */
+static void seclvl_bd_release(struct inode *inode)
+{
+        if (inode && S_ISBLK(inode->i_mode) && inode->i_security == current) {
+                struct block_device *bdev = inode->i_bdev;
+                if (bdev) {
+                        bd_release(bdev);
+                        blkdev_put(bdev);
+                        inode->i_security = NULL;
+                }
+        }
+}
+
+/**
+ * Security for writes to block devices is regulated by this seclvl
+ * function.  Deny all writes to block devices in seclvl 2.  In
+ * seclvl 1, we only deny writes to *mounted* block devices.
+ */
+static int
+seclvl_inode_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+        if (current->pid != 1 && S_ISBLK(inode->i_mode) && (mask & MAY_WRITE)) {
+                switch (seclvl) {
+                case 2:
+                        seclvl_printk(1, KERN_WARNING, "Write to block device "
+                                      "denied in secure level [%d]\n", seclvl);
+                        return -EPERM;
+                case 1:
+                        if (seclvl_bd_claim(inode)) {
+                                seclvl_printk(1, KERN_WARNING,
+                                              "Write to mounted block device "
+                                              "denied in secure level [%d]\n",
+                                              seclvl);
+                                return -EPERM;
+                        }
+                }
+        }
+        return 0;
+}
+
+/**
+ * The SUID and SGID bits cannot be set in seclvl >= 1
+ */
+static int seclvl_inode_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+        if (seclvl > 0) {
+                if (iattr->ia_valid & ATTR_MODE)
+                        if (iattr->ia_mode & S_ISUID ||
+                            iattr->ia_mode & S_ISGID) {
+                                seclvl_printk(1, KERN_WARNING, "Attempt to "
+                                              "modify SUID or SGID bit "
+                                              "denied in seclvl [%d]\n",
+                                              seclvl);
+                                return -EPERM;
+                        }
+        }
+        return 0;
+}
+
+/* release busied block devices */
+static void seclvl_file_free_security(struct file *filp)
+{
+        struct dentry *dentry = filp->f_dentry;
+        struct inode *inode = NULL;
+
+        if (dentry) {
+                inode = dentry->d_inode;
+                seclvl_bd_release(inode);
+        }
+}
+
+/**
+ * Cannot unmount in secure level 2
+ */
+static int seclvl_umount(struct vfsmount *mnt, int flags)
+{
+        if (current->pid == 1) {
+                return 0;
+        }
+        if (seclvl == 2) {
+                seclvl_printk(1, KERN_WARNING, "Attempt to unmount in secure "
+                              "level %d\n", seclvl);
+                return -EPERM;
+        }
+        return 0;
+}
+
+static struct security_operations seclvl_ops = {
+        .ptrace = seclvl_ptrace,
+        .capable = seclvl_capable,
+        .inode_permission = seclvl_inode_permission,
+        .inode_setattr = seclvl_inode_setattr,
+        .file_free_security = seclvl_file_free_security,
+        .settime = seclvl_settime,
+        .sb_umount = seclvl_umount,
+};
+
+/**
+ * Process the password-related module parameters
+ */
+static int processPassword(void)
+{
+        int rc = 0;
+        hashedPassword[0] = '\0';
+        if (*passwd) {
+                if (*sha1_passwd) {
+                        seclvl_printk(0, KERN_ERR, "Error: Both "
+                                      "passwd and sha1_passwd "
+                                      "were set, but they are mutually "
+                                      "exclusive.\n");
+                        return -EINVAL;
+                }
+                if ((rc = plaintext_to_sha1(hashedPassword, passwd,
+                                            strlen(passwd)))) {
+                        seclvl_printk(0, KERN_ERR, "Error: SHA1 support not "
+                                      "in kernel\n");
+                        return rc;
+                }
+                /* All static data goes to the BSS, which zero's the
+                 * plaintext password out for us. */
+        } else if (*sha1_passwd) {      // Base 16
+                int i;
+                i = strlen(sha1_passwd);
+                if (i != (SHA1_DIGEST_SIZE * 2)) {
+                        seclvl_printk(0, KERN_ERR, "Received [%d] bytes; "
+                                      "expected [%d] for the hexadecimal "
+                                      "representation of the SHA1 hash of "
+                                      "the password.\n",
+                                      i, (SHA1_DIGEST_SIZE * 2));
+                        return -EINVAL;
+                }
+                while ((i -= 2) + 2) {
+                        unsigned char tmp;
+                        tmp = sha1_passwd[i + 2];
+                        sha1_passwd[i + 2] = '\0';
+                        hashedPassword[i / 2] = (unsigned char)
+                            simple_strtol(&sha1_passwd[i], NULL, 16);
+                        sha1_passwd[i + 2] = tmp;
+                }
+        }
+        return 0;
+}
+
+/**
+ * Sysfs registrations
+ */
+static int doSysfsRegistrations(void)
+{
+        int rc = 0;
+        if ((rc = subsystem_register(&seclvl_subsys))) {
+                seclvl_printk(0, KERN_WARNING,
+                              "Error [%d] registering seclvl subsystem\n", rc);
+                return rc;
+        }
+        sysfs_create_file(&seclvl_subsys.kset.kobj, &sysfs_attr_seclvl.attr);
+        if (*passwd || *sha1_passwd) {
+                sysfs_create_file(&seclvl_subsys.kset.kobj,
+                                  &sysfs_attr_passwd.attr);
+        }
+        return 0;
+}
+
+/**
+ * Initialize the seclvl module.
+ */
+static int __init seclvl_init(void)
+{
+        int rc = 0;
+        if (verbosity < 0 || verbosity > 1) {
+                printk(KERN_ERR "Error: bad verbosity [%d]; only 0 or 1 "
+                       "are valid values\n", verbosity);
+                rc = -EINVAL;
+                goto exit;
+        }
+        sysfs_attr_seclvl.attr.owner = THIS_MODULE;
+        sysfs_attr_passwd.attr.owner = THIS_MODULE;
+        if (initlvl < -1 || initlvl > 2) {
+                seclvl_printk(0, KERN_ERR, "Error: bad initial securelevel "
+                              "[%d].\n", initlvl);
+                rc = -EINVAL;
+                goto exit;
+        }
+        seclvl = initlvl;
+        if ((rc = processPassword())) {
+                seclvl_printk(0, KERN_ERR, "Error processing the password "
+                              "module parameter(s): rc = [%d]\n", rc);
+                goto exit;
+        }
+        /* register ourselves with the security framework */
+        if (register_security(&seclvl_ops)) {
+                seclvl_printk(0, KERN_ERR,
+                              "seclvl: Failure registering with the "
+                              "kernel.\n");
+                /* try registering with primary module */
+                rc = mod_reg_security(MY_NAME, &seclvl_ops);
+                if (rc) {
+                        seclvl_printk(0, KERN_ERR, "seclvl: Failure "
+                                      "registering with primary security "
+                                      "module.\n");
+                        goto exit;
+                }               /* if primary module registered */
+                secondary = 1;
+        }                       /* if we registered ourselves with the security framework */
+        if ((rc = doSysfsRegistrations())) {
+                seclvl_printk(0, KERN_ERR, "Error registering with sysfs\n");
+                goto exit;
+        }
+        seclvl_printk(0, KERN_INFO, "seclvl: Successfully initialized.\n");
+ exit:
+        if (rc) {
+                printk(KERN_ERR "seclvl: Error during initialization: rc = "
+                       "[%d]\n", rc);
+        }
+        return rc;
+}
+
+/**
+ * Remove the seclvl module.
+ */
+static void __exit seclvl_exit(void)
+{
+        sysfs_remove_file(&seclvl_subsys.kset.kobj, &sysfs_attr_seclvl.attr);
+        if (*passwd || *sha1_passwd) {
+                sysfs_remove_file(&seclvl_subsys.kset.kobj,
+                                  &sysfs_attr_passwd.attr);
+        }
+        subsystem_unregister(&seclvl_subsys);
+        if (secondary == 1) {
+                mod_unreg_security(MY_NAME, &seclvl_ops);
+        } else if (unregister_security(&seclvl_ops)) {
+                seclvl_printk(0, KERN_INFO,
+                              "seclvl: Failure unregistering with the "
+                              "kernel\n");
+        }
+}
+
+module_init(seclvl_init);
+module_exit(seclvl_exit);
+
+MODULE_AUTHOR("Michael A. Halcrow <mike@halcrow.us>");
+MODULE_DESCRIPTION("LSM implementation of the BSD Secure Levels");
+MODULE_LICENSE("GPL");