blob: 8f6291991fbcb165fee06155e390027bbbcabd67 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/**
2 * BSD Secure Levels LSM
3 *
4 * Maintainers:
5 * Michael A. Halcrow <mike@halcrow.us>
6 * Serge Hallyn <hallyn@cs.wm.edu>
7 *
8 * Copyright (c) 2001 WireX Communications, Inc <chris@wirex.com>
9 * Copyright (c) 2001 Greg Kroah-Hartman <greg@kroah.com>
10 * Copyright (c) 2002 International Business Machines <robb@austin.ibm.com>
Davi Arnaut6bb08da2006-03-23 02:59:25 -080011 * Copyright (c) 2006 Davi E. M. Arnaut <davi.arnaut@gmail.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 */
18
Herbert Xu35058682006-08-24 19:10:20 +100019#include <linux/err.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/module.h>
21#include <linux/moduleparam.h>
22#include <linux/kernel.h>
23#include <linux/init.h>
24#include <linux/security.h>
25#include <linux/netlink.h>
26#include <linux/fs.h>
27#include <linux/namei.h>
28#include <linux/mount.h>
29#include <linux/capability.h>
30#include <linux/time.h>
31#include <linux/proc_fs.h>
32#include <linux/kobject.h>
33#include <linux/crypto.h>
34#include <asm/scatterlist.h>
Davi Arnaut6bb08da2006-03-23 02:59:25 -080035#include <linux/scatterlist.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include <linux/gfp.h>
37#include <linux/sysfs.h>
38
39#define SHA1_DIGEST_SIZE 20
40
41/**
42 * Module parameter that defines the initial secure level.
43 *
44 * When built as a module, it defaults to seclvl 1, which is the
45 * behavior of BSD secure levels. Note that this default behavior
46 * wrecks havoc on a machine when the seclvl module is compiled into
47 * the kernel. In that case, we default to seclvl 0.
48 */
49#ifdef CONFIG_SECURITY_SECLVL_MODULE
50static int initlvl = 1;
51#else
52static int initlvl;
53#endif
54module_param(initlvl, int, 0);
55MODULE_PARM_DESC(initlvl, "Initial secure level (defaults to 1)");
56
57/* Module parameter that defines the verbosity level */
58static int verbosity;
59module_param(verbosity, int, 0);
60MODULE_PARM_DESC(verbosity, "Initial verbosity level (0 or 1; defaults to "
61 "0, which is Quiet)");
62
63/**
64 * Optional password which can be passed in to bring seclvl to 0
65 * (i.e., for halt/reboot). Defaults to NULL (the passwd attribute
66 * file will not be registered in sysfs).
67 *
68 * This gets converted to its SHA1 hash when stored. It's probably
69 * not a good idea to use this parameter when loading seclvl from a
70 * script; use sha1_passwd instead.
71 */
72
73#define MAX_PASSWD_SIZE 32
74static char passwd[MAX_PASSWD_SIZE];
75module_param_string(passwd, passwd, sizeof(passwd), 0);
76MODULE_PARM_DESC(passwd,
77 "Plaintext of password that sets seclvl=0 when written to "
78 "(sysfs mount point)/seclvl/passwd\n");
79
80/**
81 * SHA1 hashed version of the optional password which can be passed in
82 * to bring seclvl to 0 (i.e., for halt/reboot). Must be in
83 * hexadecimal format (40 characters). Defaults to NULL (the passwd
84 * attribute file will not be registered in sysfs).
85 *
86 * Use the sha1sum utility to generate the SHA1 hash of a password:
87 *
88 * echo -n "secret" | sha1sum
89 */
90#define MAX_SHA1_PASSWD 41
91static char sha1_passwd[MAX_SHA1_PASSWD];
92module_param_string(sha1_passwd, sha1_passwd, sizeof(sha1_passwd), 0);
93MODULE_PARM_DESC(sha1_passwd,
94 "SHA1 hash (40 hexadecimal characters) of password that "
95 "sets seclvl=0 when plaintext password is written to "
96 "(sysfs mount point)/seclvl/passwd\n");
97
98static int hideHash = 1;
99module_param(hideHash, int, 0);
100MODULE_PARM_DESC(hideHash, "When set to 0, reading seclvl/passwd from sysfs "
101 "will return the SHA1-hashed value of the password that "
102 "lowers the secure level to 0.\n");
103
104#define MY_NAME "seclvl"
105
106/**
107 * This time-limits log writes to one per second.
108 */
109#define seclvl_printk(verb, type, fmt, arg...) \
110 do { \
111 if (verbosity >= verb) { \
112 static unsigned long _prior; \
113 unsigned long _now = jiffies; \
114 if ((_now - _prior) > HZ) { \
115 printk(type "%s: %s: " fmt, \
116 MY_NAME, __FUNCTION__ , \
117 ## arg); \
118 _prior = _now; \
119 } \
120 } \
121 } while (0)
122
123/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 * The actual security level. Ranges between -1 and 2 inclusive.
125 */
126static int seclvl;
127
128/**
129 * flag to keep track of how we were registered
130 */
131static int secondary;
132
133/**
134 * Verifies that the requested secure level is valid, given the current
135 * secure level.
136 */
137static int seclvl_sanity(int reqlvl)
138{
139 if ((reqlvl < -1) || (reqlvl > 2)) {
140 seclvl_printk(1, KERN_WARNING, "Attempt to set seclvl out of "
141 "range: [%d]\n", reqlvl);
142 return -EINVAL;
143 }
144 if ((seclvl == 0) && (reqlvl == -1))
145 return 0;
146 if (reqlvl < seclvl) {
147 seclvl_printk(1, KERN_WARNING, "Attempt to lower seclvl to "
148 "[%d]\n", reqlvl);
149 return -EPERM;
150 }
151 return 0;
152}
153
154/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 * security level advancement rules:
156 * Valid levels are -1 through 2, inclusive.
157 * From -1, stuck. [ in case compiled into kernel ]
158 * From 0 or above, can only increment.
159 */
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500160static void do_seclvl_advance(void *data, u64 val)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161{
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500162 int ret;
163 int newlvl = (int)val;
164
165 ret = seclvl_sanity(newlvl);
166 if (ret)
167 return;
168
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 if (newlvl > 2) {
170 seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl "
171 "[%d]\n", newlvl);
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500172 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 }
174 if (seclvl == -1) {
175 seclvl_printk(1, KERN_WARNING, "Not allowed to advance to "
176 "seclvl [%d]\n", seclvl);
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500177 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 }
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500179 seclvl = newlvl; /* would it be more "correct" to set *data? */
180 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181}
182
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500183static u64 seclvl_int_get(void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184{
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500185 return *(int *)data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186}
187
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500188DEFINE_SIMPLE_ATTRIBUTE(seclvl_file_ops, seclvl_int_get, do_seclvl_advance, "%lld\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
190static unsigned char hashedPassword[SHA1_DIGEST_SIZE];
191
192/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 * Converts a block of plaintext of into its SHA1 hashed value.
194 *
195 * It would be nice if crypto had a wrapper to do this for us linear
196 * people...
197 */
198static int
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800199plaintext_to_sha1(unsigned char *hash, const char *plaintext, unsigned int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200{
Herbert Xu35058682006-08-24 19:10:20 +1000201 struct hash_desc desc;
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800202 struct scatterlist sg;
Herbert Xu35058682006-08-24 19:10:20 +1000203 int err;
204
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 if (len > PAGE_SIZE) {
206 seclvl_printk(0, KERN_ERR, "Plaintext password too large (%d "
207 "characters). Largest possible is %lu "
208 "bytes.\n", len, PAGE_SIZE);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800209 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 }
Herbert Xu35058682006-08-24 19:10:20 +1000211 desc.tfm = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC);
212 if (IS_ERR(desc.tfm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 seclvl_printk(0, KERN_ERR,
214 "Failed to load transform for SHA1\n");
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800215 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 }
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800217 sg_init_one(&sg, (u8 *)plaintext, len);
Herbert Xu35058682006-08-24 19:10:20 +1000218 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
219 err = crypto_hash_digest(&desc, &sg, len, hash);
220 crypto_free_hash(desc.tfm);
221 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222}
223
224/**
225 * Called whenever the user writes to the sysfs passwd handle to this kernel
226 * object. It hashes the password and compares the hashed results.
227 */
228static ssize_t
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500229passwd_write_file(struct file * file, const char __user * buf,
230 size_t count, loff_t *ppos)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231{
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800232 char *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 int len;
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800234 unsigned char tmp[SHA1_DIGEST_SIZE];
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 if (!*passwd && !*sha1_passwd) {
237 seclvl_printk(0, KERN_ERR, "Attempt to password-unlock the "
238 "seclvl module, but neither a plain text "
239 "password nor a SHA1 hashed password was "
240 "passed in as a module parameter! This is a "
241 "bug, since it should not be possible to be in "
242 "this part of the module; please tell a "
243 "maintainer about this event.\n");
244 return -EINVAL;
245 }
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500246
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800247 if (count >= PAGE_SIZE)
Serge Hallyn9afa57b2005-09-16 19:27:57 -0700248 return -EINVAL;
Andrew Mortond15c5742005-09-16 19:27:56 -0700249 if (*ppos != 0)
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500250 return -EINVAL;
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800251 p = kmalloc(count, GFP_KERNEL);
252 if (!p)
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500253 return -ENOMEM;
254 len = -EFAULT;
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800255 if (copy_from_user(p, buf, count))
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500256 goto out;
257
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800258 len = count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 /* ``echo "secret" > seclvl/passwd'' includes a newline */
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800260 if (p[len - 1] == '\n')
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 len--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 /* Hash the password, then compare the hashed values */
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800263 if ((len = plaintext_to_sha1(tmp, p, len))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 seclvl_printk(0, KERN_ERR, "Error hashing password: rc = "
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800265 "[%d]\n", len);
266 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 }
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800268
269 len = -EPERM;
270 if (memcmp(hashedPassword, tmp, SHA1_DIGEST_SIZE))
271 goto out;
272
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 seclvl_printk(0, KERN_INFO,
274 "Password accepted; seclvl reduced to 0.\n");
275 seclvl = 0;
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500276 len = count;
277
278out:
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800279 kfree (p);
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500280 return len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281}
282
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500283static struct file_operations passwd_file_ops = {
284 .write = passwd_write_file,
285};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286
287/**
288 * Explicitely disallow ptrace'ing the init process.
289 */
290static int seclvl_ptrace(struct task_struct *parent, struct task_struct *child)
291{
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800292 if (seclvl >= 0 && child->pid == 1) {
293 seclvl_printk(1, KERN_WARNING, "Attempt to ptrace "
294 "the init process dissallowed in "
295 "secure level %d\n", seclvl);
296 return -EPERM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 }
298 return 0;
299}
300
301/**
302 * Capability checks for seclvl. The majority of the policy
303 * enforcement for seclvl takes place here.
304 */
305static int seclvl_capable(struct task_struct *tsk, int cap)
306{
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800307 int rc = 0;
308
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 /* init can do anything it wants */
310 if (tsk->pid == 1)
311 return 0;
312
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800313 if (seclvl > 0) {
314 rc = -EPERM;
315
316 if (cap == CAP_LINUX_IMMUTABLE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317 seclvl_printk(1, KERN_WARNING, "Attempt to modify "
318 "the IMMUTABLE and/or APPEND extended "
319 "attribute on a file with the IMMUTABLE "
320 "and/or APPEND extended attribute set "
321 "denied in seclvl [%d]\n", seclvl);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800322 else if (cap == CAP_SYS_RAWIO)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 seclvl_printk(1, KERN_WARNING, "Attempt to perform "
324 "raw I/O while in secure level [%d] "
325 "denied\n", seclvl);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800326 else if (cap == CAP_NET_ADMIN)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 seclvl_printk(1, KERN_WARNING, "Attempt to perform "
328 "network administrative task while "
329 "in secure level [%d] denied\n", seclvl);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800330 else if (cap == CAP_SETUID)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 seclvl_printk(1, KERN_WARNING, "Attempt to setuid "
332 "while in secure level [%d] denied\n",
333 seclvl);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800334 else if (cap == CAP_SETGID)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 seclvl_printk(1, KERN_WARNING, "Attempt to setgid "
336 "while in secure level [%d] denied\n",
337 seclvl);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800338 else if (cap == CAP_SYS_MODULE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 seclvl_printk(1, KERN_WARNING, "Attempt to perform "
340 "a module operation while in secure "
341 "level [%d] denied\n", seclvl);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800342 else
343 rc = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 }
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800345
346 if (!rc) {
347 if (!(cap_is_fs_cap(cap) ? tsk->fsuid == 0 : tsk->euid == 0))
348 rc = -EPERM;
349 }
350
351 if (rc)
352 seclvl_printk(1, KERN_WARNING, "Capability denied\n");
353
354 return rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355}
356
357/**
358 * Disallow reversing the clock in seclvl > 1
359 */
360static int seclvl_settime(struct timespec *tv, struct timezone *tz)
361{
Linus Torvalds951069e2006-01-31 10:16:55 -0800362 if (tv && seclvl > 1) {
363 struct timespec now;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 now = current_kernel_time();
365 if (tv->tv_sec < now.tv_sec ||
366 (tv->tv_sec == now.tv_sec && tv->tv_nsec < now.tv_nsec)) {
367 seclvl_printk(1, KERN_WARNING, "Attempt to decrement "
368 "time in secure level %d denied: "
369 "current->pid = [%d], "
370 "current->group_leader->pid = [%d]\n",
371 seclvl, current->pid,
372 current->group_leader->pid);
373 return -EPERM;
374 } /* if attempt to decrement time */
375 } /* if seclvl > 1 */
376 return 0;
377}
378
379/* claim the blockdev to exclude mounters, release on file close */
380static int seclvl_bd_claim(struct inode *inode)
381{
382 int holder;
383 struct block_device *bdev = NULL;
384 dev_t dev = inode->i_rdev;
385 bdev = open_by_devnum(dev, FMODE_WRITE);
386 if (bdev) {
387 if (bd_claim(bdev, &holder)) {
388 blkdev_put(bdev);
389 return -EPERM;
390 }
391 /* claimed, mark it to release on close */
392 inode->i_security = current;
393 }
394 return 0;
395}
396
397/* release the blockdev if you claimed it */
398static void seclvl_bd_release(struct inode *inode)
399{
400 if (inode && S_ISBLK(inode->i_mode) && inode->i_security == current) {
401 struct block_device *bdev = inode->i_bdev;
402 if (bdev) {
403 bd_release(bdev);
404 blkdev_put(bdev);
405 inode->i_security = NULL;
406 }
407 }
408}
409
410/**
411 * Security for writes to block devices is regulated by this seclvl
412 * function. Deny all writes to block devices in seclvl 2. In
413 * seclvl 1, we only deny writes to *mounted* block devices.
414 */
415static int
416seclvl_inode_permission(struct inode *inode, int mask, struct nameidata *nd)
417{
418 if (current->pid != 1 && S_ISBLK(inode->i_mode) && (mask & MAY_WRITE)) {
419 switch (seclvl) {
420 case 2:
421 seclvl_printk(1, KERN_WARNING, "Write to block device "
422 "denied in secure level [%d]\n", seclvl);
423 return -EPERM;
424 case 1:
425 if (seclvl_bd_claim(inode)) {
426 seclvl_printk(1, KERN_WARNING,
427 "Write to mounted block device "
428 "denied in secure level [%d]\n",
429 seclvl);
430 return -EPERM;
431 }
432 }
433 }
434 return 0;
435}
436
437/**
438 * The SUID and SGID bits cannot be set in seclvl >= 1
439 */
440static int seclvl_inode_setattr(struct dentry *dentry, struct iattr *iattr)
441{
442 if (seclvl > 0) {
443 if (iattr->ia_valid & ATTR_MODE)
444 if (iattr->ia_mode & S_ISUID ||
445 iattr->ia_mode & S_ISGID) {
446 seclvl_printk(1, KERN_WARNING, "Attempt to "
447 "modify SUID or SGID bit "
448 "denied in seclvl [%d]\n",
449 seclvl);
450 return -EPERM;
451 }
452 }
453 return 0;
454}
455
456/* release busied block devices */
457static void seclvl_file_free_security(struct file *filp)
458{
459 struct dentry *dentry = filp->f_dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800461 if (dentry)
462 seclvl_bd_release(dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463}
464
465/**
466 * Cannot unmount in secure level 2
467 */
468static int seclvl_umount(struct vfsmount *mnt, int flags)
469{
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800470 if (current->pid != 1 && seclvl == 2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 seclvl_printk(1, KERN_WARNING, "Attempt to unmount in secure "
472 "level %d\n", seclvl);
473 return -EPERM;
474 }
475 return 0;
476}
477
478static struct security_operations seclvl_ops = {
479 .ptrace = seclvl_ptrace,
480 .capable = seclvl_capable,
481 .inode_permission = seclvl_inode_permission,
482 .inode_setattr = seclvl_inode_setattr,
483 .file_free_security = seclvl_file_free_security,
484 .settime = seclvl_settime,
485 .sb_umount = seclvl_umount,
486};
487
488/**
489 * Process the password-related module parameters
490 */
491static int processPassword(void)
492{
493 int rc = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 if (*passwd) {
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800495 char *p;
496
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 if (*sha1_passwd) {
498 seclvl_printk(0, KERN_ERR, "Error: Both "
499 "passwd and sha1_passwd "
500 "were set, but they are mutually "
501 "exclusive.\n");
502 return -EINVAL;
503 }
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800504
505 p = kstrdup(passwd, GFP_KERNEL);
506 if (p == NULL)
507 return -ENOMEM;
508
509 if ((rc = plaintext_to_sha1(hashedPassword, p, strlen(p))))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 seclvl_printk(0, KERN_ERR, "Error: SHA1 support not "
511 "in kernel\n");
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800512
513 kfree (p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 /* All static data goes to the BSS, which zero's the
515 * plaintext password out for us. */
516 } else if (*sha1_passwd) { // Base 16
517 int i;
518 i = strlen(sha1_passwd);
519 if (i != (SHA1_DIGEST_SIZE * 2)) {
520 seclvl_printk(0, KERN_ERR, "Received [%d] bytes; "
521 "expected [%d] for the hexadecimal "
522 "representation of the SHA1 hash of "
523 "the password.\n",
524 i, (SHA1_DIGEST_SIZE * 2));
525 return -EINVAL;
526 }
527 while ((i -= 2) + 2) {
528 unsigned char tmp;
529 tmp = sha1_passwd[i + 2];
530 sha1_passwd[i + 2] = '\0';
531 hashedPassword[i / 2] = (unsigned char)
532 simple_strtol(&sha1_passwd[i], NULL, 16);
533 sha1_passwd[i + 2] = tmp;
534 }
535 }
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800536 return rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537}
538
539/**
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500540 * securityfs registrations
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 */
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500542struct dentry *dir_ino, *seclvl_ino, *passwd_ino;
543
544static int seclvlfs_register(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545{
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800546 int rc = 0;
547
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500548 dir_ino = securityfs_create_dir("seclvl", NULL);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800549
550 if (IS_ERR(dir_ino))
551 return PTR_ERR(dir_ino);
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500552
553 seclvl_ino = securityfs_create_file("seclvl", S_IRUGO | S_IWUSR,
554 dir_ino, &seclvl, &seclvl_file_ops);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800555 if (IS_ERR(seclvl_ino)) {
556 rc = PTR_ERR(seclvl_ino);
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500557 goto out_deldir;
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800558 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 if (*passwd || *sha1_passwd) {
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500560 passwd_ino = securityfs_create_file("passwd", S_IRUGO | S_IWUSR,
561 dir_ino, NULL, &passwd_file_ops);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800562 if (IS_ERR(passwd_ino)) {
563 rc = PTR_ERR(passwd_ino);
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500564 goto out_delf;
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800565 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 }
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800567 return rc;
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500568
serue@us.ibm.com5a73c302005-07-08 15:44:19 -0500569out_delf:
570 securityfs_remove(seclvl_ino);
571
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800572out_deldir:
573 securityfs_remove(dir_ino);
574
575 return rc;
576}
577
578static void seclvlfs_unregister(void)
579{
580 securityfs_remove(seclvl_ino);
581
582 if (*passwd || *sha1_passwd)
583 securityfs_remove(passwd_ino);
584
585 securityfs_remove(dir_ino);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586}
587
588/**
589 * Initialize the seclvl module.
590 */
591static int __init seclvl_init(void)
592{
593 int rc = 0;
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800594 static char once;
595
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 if (verbosity < 0 || verbosity > 1) {
597 printk(KERN_ERR "Error: bad verbosity [%d]; only 0 or 1 "
598 "are valid values\n", verbosity);
599 rc = -EINVAL;
600 goto exit;
601 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 if (initlvl < -1 || initlvl > 2) {
603 seclvl_printk(0, KERN_ERR, "Error: bad initial securelevel "
604 "[%d].\n", initlvl);
605 rc = -EINVAL;
606 goto exit;
607 }
608 seclvl = initlvl;
609 if ((rc = processPassword())) {
610 seclvl_printk(0, KERN_ERR, "Error processing the password "
611 "module parameter(s): rc = [%d]\n", rc);
612 goto exit;
613 }
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800614
615 if ((rc = seclvlfs_register())) {
616 seclvl_printk(0, KERN_ERR, "Error registering with sysfs\n");
617 goto exit;
618 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 /* register ourselves with the security framework */
620 if (register_security(&seclvl_ops)) {
621 seclvl_printk(0, KERN_ERR,
622 "seclvl: Failure registering with the "
623 "kernel.\n");
624 /* try registering with primary module */
625 rc = mod_reg_security(MY_NAME, &seclvl_ops);
626 if (rc) {
627 seclvl_printk(0, KERN_ERR, "seclvl: Failure "
628 "registering with primary security "
629 "module.\n");
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800630 seclvlfs_unregister();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 goto exit;
632 } /* if primary module registered */
633 secondary = 1;
634 } /* if we registered ourselves with the security framework */
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800635
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 seclvl_printk(0, KERN_INFO, "seclvl: Successfully initialized.\n");
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800637
638 if (once) {
639 once = 1;
640 seclvl_printk(0, KERN_INFO, "seclvl is going away. It has been "
641 "buggy for ages. Also, be warned that "
642 "Securelevels are useless.");
643 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 exit:
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800645 if (rc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 printk(KERN_ERR "seclvl: Error during initialization: rc = "
647 "[%d]\n", rc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 return rc;
649}
650
651/**
652 * Remove the seclvl module.
653 */
654static void __exit seclvl_exit(void)
655{
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800656 seclvlfs_unregister();
657
658 if (secondary)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 mod_unreg_security(MY_NAME, &seclvl_ops);
Davi Arnaut6bb08da2006-03-23 02:59:25 -0800660 else if (unregister_security(&seclvl_ops))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 seclvl_printk(0, KERN_INFO,
662 "seclvl: Failure unregistering with the "
663 "kernel\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664}
665
666module_init(seclvl_init);
667module_exit(seclvl_exit);
668
669MODULE_AUTHOR("Michael A. Halcrow <mike@halcrow.us>");
670MODULE_DESCRIPTION("LSM implementation of the BSD Secure Levels");
671MODULE_LICENSE("GPL");