Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/security/seclvl.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 20546 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /** |
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> |
11 | * |
12 | * This program is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU General Public License as published by |
14 | * the Free Software Foundation; either version 2 of the License, or |
15 | * (at your option) any later version. |
16 | */ |
17 | |
18 | #include <linux/config.h> |
19 | #include <linux/module.h> |
20 | #include <linux/moduleparam.h> |
21 | #include <linux/kernel.h> |
22 | #include <linux/init.h> |
23 | #include <linux/security.h> |
24 | #include <linux/netlink.h> |
25 | #include <linux/fs.h> |
26 | #include <linux/namei.h> |
27 | #include <linux/mount.h> |
28 | #include <linux/capability.h> |
29 | #include <linux/time.h> |
30 | #include <linux/proc_fs.h> |
31 | #include <linux/kobject.h> |
32 | #include <linux/crypto.h> |
33 | #include <asm/scatterlist.h> |
34 | #include <linux/gfp.h> |
35 | #include <linux/sysfs.h> |
36 | |
37 | #define SHA1_DIGEST_SIZE 20 |
38 | |
39 | /** |
40 | * Module parameter that defines the initial secure level. |
41 | * |
42 | * When built as a module, it defaults to seclvl 1, which is the |
43 | * behavior of BSD secure levels. Note that this default behavior |
44 | * wrecks havoc on a machine when the seclvl module is compiled into |
45 | * the kernel. In that case, we default to seclvl 0. |
46 | */ |
47 | #ifdef CONFIG_SECURITY_SECLVL_MODULE |
48 | static int initlvl = 1; |
49 | #else |
50 | static int initlvl; |
51 | #endif |
52 | module_param(initlvl, int, 0); |
53 | MODULE_PARM_DESC(initlvl, "Initial secure level (defaults to 1)"); |
54 | |
55 | /* Module parameter that defines the verbosity level */ |
56 | static int verbosity; |
57 | module_param(verbosity, int, 0); |
58 | MODULE_PARM_DESC(verbosity, "Initial verbosity level (0 or 1; defaults to " |
59 | "0, which is Quiet)"); |
60 | |
61 | /** |
62 | * Optional password which can be passed in to bring seclvl to 0 |
63 | * (i.e., for halt/reboot). Defaults to NULL (the passwd attribute |
64 | * file will not be registered in sysfs). |
65 | * |
66 | * This gets converted to its SHA1 hash when stored. It's probably |
67 | * not a good idea to use this parameter when loading seclvl from a |
68 | * script; use sha1_passwd instead. |
69 | */ |
70 | |
71 | #define MAX_PASSWD_SIZE 32 |
72 | static char passwd[MAX_PASSWD_SIZE]; |
73 | module_param_string(passwd, passwd, sizeof(passwd), 0); |
74 | MODULE_PARM_DESC(passwd, |
75 | "Plaintext of password that sets seclvl=0 when written to " |
76 | "(sysfs mount point)/seclvl/passwd\n"); |
77 | |
78 | /** |
79 | * SHA1 hashed version of the optional password which can be passed in |
80 | * to bring seclvl to 0 (i.e., for halt/reboot). Must be in |
81 | * hexadecimal format (40 characters). Defaults to NULL (the passwd |
82 | * attribute file will not be registered in sysfs). |
83 | * |
84 | * Use the sha1sum utility to generate the SHA1 hash of a password: |
85 | * |
86 | * echo -n "secret" | sha1sum |
87 | */ |
88 | #define MAX_SHA1_PASSWD 41 |
89 | static char sha1_passwd[MAX_SHA1_PASSWD]; |
90 | module_param_string(sha1_passwd, sha1_passwd, sizeof(sha1_passwd), 0); |
91 | MODULE_PARM_DESC(sha1_passwd, |
92 | "SHA1 hash (40 hexadecimal characters) of password that " |
93 | "sets seclvl=0 when plaintext password is written to " |
94 | "(sysfs mount point)/seclvl/passwd\n"); |
95 | |
96 | static int hideHash = 1; |
97 | module_param(hideHash, int, 0); |
98 | MODULE_PARM_DESC(hideHash, "When set to 0, reading seclvl/passwd from sysfs " |
99 | "will return the SHA1-hashed value of the password that " |
100 | "lowers the secure level to 0.\n"); |
101 | |
102 | #define MY_NAME "seclvl" |
103 | |
104 | /** |
105 | * This time-limits log writes to one per second. |
106 | */ |
107 | #define seclvl_printk(verb, type, fmt, arg...) \ |
108 | do { \ |
109 | if (verbosity >= verb) { \ |
110 | static unsigned long _prior; \ |
111 | unsigned long _now = jiffies; \ |
112 | if ((_now - _prior) > HZ) { \ |
113 | printk(type "%s: %s: " fmt, \ |
114 | MY_NAME, __FUNCTION__ , \ |
115 | ## arg); \ |
116 | _prior = _now; \ |
117 | } \ |
118 | } \ |
119 | } while (0) |
120 | |
121 | /** |
122 | * kobject stuff |
123 | */ |
124 | |
125 | struct subsystem seclvl_subsys; |
126 | |
127 | struct seclvl_obj { |
128 | char *name; |
129 | struct list_head slot_list; |
130 | struct kobject kobj; |
131 | }; |
132 | |
133 | /** |
134 | * There is a seclvl_attribute struct for each file in sysfs. |
135 | * |
136 | * In our case, we have one of these structs for "passwd" and another |
137 | * for "seclvl". |
138 | */ |
139 | struct seclvl_attribute { |
140 | struct attribute attr; |
141 | ssize_t(*show) (struct seclvl_obj *, char *); |
142 | ssize_t(*store) (struct seclvl_obj *, const char *, size_t); |
143 | }; |
144 | |
145 | /** |
146 | * When this function is called, one of the files in sysfs is being |
147 | * written to. attribute->store is a function pointer to whatever the |
148 | * struct seclvl_attribute store function pointer points to. It is |
149 | * unique for "passwd" and "seclvl". |
150 | */ |
151 | static ssize_t |
152 | seclvl_attr_store(struct kobject *kobj, |
153 | struct attribute *attr, const char *buf, size_t len) |
154 | { |
155 | struct seclvl_obj *obj = container_of(kobj, struct seclvl_obj, kobj); |
156 | struct seclvl_attribute *attribute = |
157 | container_of(attr, struct seclvl_attribute, attr); |
158 | return (attribute->store ? attribute->store(obj, buf, len) : 0); |
159 | } |
160 | |
161 | static ssize_t |
162 | seclvl_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) |
163 | { |
164 | struct seclvl_obj *obj = container_of(kobj, struct seclvl_obj, kobj); |
165 | struct seclvl_attribute *attribute = |
166 | container_of(attr, struct seclvl_attribute, attr); |
167 | return (attribute->show ? attribute->show(obj, buf) : 0); |
168 | } |
169 | |
170 | /** |
171 | * Callback function pointers for show and store |
172 | */ |
173 | static struct sysfs_ops seclvlfs_sysfs_ops = { |
174 | .show = seclvl_attr_show, |
175 | .store = seclvl_attr_store, |
176 | }; |
177 | |
178 | static struct kobj_type seclvl_ktype = { |
179 | .sysfs_ops = &seclvlfs_sysfs_ops |
180 | }; |
181 | |
182 | decl_subsys(seclvl, &seclvl_ktype, NULL); |
183 | |
184 | /** |
185 | * The actual security level. Ranges between -1 and 2 inclusive. |
186 | */ |
187 | static int seclvl; |
188 | |
189 | /** |
190 | * flag to keep track of how we were registered |
191 | */ |
192 | static int secondary; |
193 | |
194 | /** |
195 | * Verifies that the requested secure level is valid, given the current |
196 | * secure level. |
197 | */ |
198 | static int seclvl_sanity(int reqlvl) |
199 | { |
200 | if ((reqlvl < -1) || (reqlvl > 2)) { |
201 | seclvl_printk(1, KERN_WARNING, "Attempt to set seclvl out of " |
202 | "range: [%d]\n", reqlvl); |
203 | return -EINVAL; |
204 | } |
205 | if ((seclvl == 0) && (reqlvl == -1)) |
206 | return 0; |
207 | if (reqlvl < seclvl) { |
208 | seclvl_printk(1, KERN_WARNING, "Attempt to lower seclvl to " |
209 | "[%d]\n", reqlvl); |
210 | return -EPERM; |
211 | } |
212 | return 0; |
213 | } |
214 | |
215 | /** |
216 | * Called whenever the user reads the sysfs handle to this kernel |
217 | * object |
218 | */ |
219 | static ssize_t seclvl_read_file(struct seclvl_obj *obj, char *buff) |
220 | { |
221 | return snprintf(buff, PAGE_SIZE, "%d\n", seclvl); |
222 | } |
223 | |
224 | /** |
225 | * security level advancement rules: |
226 | * Valid levels are -1 through 2, inclusive. |
227 | * From -1, stuck. [ in case compiled into kernel ] |
228 | * From 0 or above, can only increment. |
229 | */ |
230 | static int do_seclvl_advance(int newlvl) |
231 | { |
232 | if (newlvl <= seclvl) { |
233 | seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl " |
234 | "[%d]\n", newlvl); |
235 | return -EINVAL; |
236 | } |
237 | if (newlvl > 2) { |
238 | seclvl_printk(1, KERN_WARNING, "Cannot advance to seclvl " |
239 | "[%d]\n", newlvl); |
240 | return -EINVAL; |
241 | } |
242 | if (seclvl == -1) { |
243 | seclvl_printk(1, KERN_WARNING, "Not allowed to advance to " |
244 | "seclvl [%d]\n", seclvl); |
245 | return -EPERM; |
246 | } |
247 | seclvl = newlvl; |
248 | return 0; |
249 | } |
250 | |
251 | /** |
252 | * Called whenever the user writes to the sysfs handle to this kernel |
253 | * object (seclvl/seclvl). It expects a single-digit number. |
254 | */ |
255 | static ssize_t |
256 | seclvl_write_file(struct seclvl_obj *obj, const char *buff, size_t count) |
257 | { |
258 | unsigned long val; |
259 | if (count > 2 || (count == 2 && buff[1] != '\n')) { |
260 | seclvl_printk(1, KERN_WARNING, "Invalid value passed to " |
261 | "seclvl: [%s]\n", buff); |
262 | return -EINVAL; |
263 | } |
264 | val = buff[0] - 48; |
265 | if (seclvl_sanity(val)) { |
266 | seclvl_printk(1, KERN_WARNING, "Illegal secure level " |
267 | "requested: [%d]\n", (int)val); |
268 | return -EPERM; |
269 | } |
270 | if (do_seclvl_advance(val)) { |
271 | seclvl_printk(0, KERN_ERR, "Failure advancing security level " |
272 | "to %lu\n", val); |
273 | } |
274 | return count; |
275 | } |
276 | |
277 | /* Generate sysfs_attr_seclvl */ |
278 | static struct seclvl_attribute sysfs_attr_seclvl = |
279 | __ATTR(seclvl, (S_IFREG | S_IRUGO | S_IWUSR), seclvl_read_file, |
280 | seclvl_write_file); |
281 | |
282 | static unsigned char hashedPassword[SHA1_DIGEST_SIZE]; |
283 | |
284 | /** |
285 | * Called whenever the user reads the sysfs passwd handle. |
286 | */ |
287 | static ssize_t seclvl_read_passwd(struct seclvl_obj *obj, char *buff) |
288 | { |
289 | /* So just how good *is* your password? :-) */ |
290 | char tmp[3]; |
291 | int i = 0; |
292 | buff[0] = '\0'; |
293 | if (hideHash) { |
294 | /* Security through obscurity */ |
295 | return 0; |
296 | } |
297 | while (i < SHA1_DIGEST_SIZE) { |
298 | snprintf(tmp, 3, "%02x", hashedPassword[i]); |
299 | strncat(buff, tmp, 2); |
300 | i++; |
301 | } |
302 | strcat(buff, "\n"); |
303 | return ((SHA1_DIGEST_SIZE * 2) + 1); |
304 | } |
305 | |
306 | /** |
307 | * Converts a block of plaintext of into its SHA1 hashed value. |
308 | * |
309 | * It would be nice if crypto had a wrapper to do this for us linear |
310 | * people... |
311 | */ |
312 | static int |
313 | plaintext_to_sha1(unsigned char *hash, const char *plaintext, int len) |
314 | { |
315 | char *pgVirtAddr; |
316 | struct crypto_tfm *tfm; |
317 | struct scatterlist sg[1]; |
318 | if (len > PAGE_SIZE) { |
319 | seclvl_printk(0, KERN_ERR, "Plaintext password too large (%d " |
320 | "characters). Largest possible is %lu " |
321 | "bytes.\n", len, PAGE_SIZE); |
322 | return -ENOMEM; |
323 | } |
324 | tfm = crypto_alloc_tfm("sha1", 0); |
325 | if (tfm == NULL) { |
326 | seclvl_printk(0, KERN_ERR, |
327 | "Failed to load transform for SHA1\n"); |
328 | return -ENOSYS; |
329 | } |
330 | // Just get a new page; don't play around with page boundaries |
331 | // and scatterlists. |
332 | pgVirtAddr = (char *)__get_free_page(GFP_KERNEL); |
333 | sg[0].page = virt_to_page(pgVirtAddr); |
334 | sg[0].offset = 0; |
335 | sg[0].length = len; |
336 | strncpy(pgVirtAddr, plaintext, len); |
337 | crypto_digest_init(tfm); |
338 | crypto_digest_update(tfm, sg, 1); |
339 | crypto_digest_final(tfm, hash); |
340 | crypto_free_tfm(tfm); |
341 | free_page((unsigned long)pgVirtAddr); |
342 | return 0; |
343 | } |
344 | |
345 | /** |
346 | * Called whenever the user writes to the sysfs passwd handle to this kernel |
347 | * object. It hashes the password and compares the hashed results. |
348 | */ |
349 | static ssize_t |
350 | seclvl_write_passwd(struct seclvl_obj *obj, const char *buff, size_t count) |
351 | { |
352 | int i; |
353 | unsigned char tmp[SHA1_DIGEST_SIZE]; |
354 | int rc; |
355 | int len; |
356 | if (!*passwd && !*sha1_passwd) { |
357 | seclvl_printk(0, KERN_ERR, "Attempt to password-unlock the " |
358 | "seclvl module, but neither a plain text " |
359 | "password nor a SHA1 hashed password was " |
360 | "passed in as a module parameter! This is a " |
361 | "bug, since it should not be possible to be in " |
362 | "this part of the module; please tell a " |
363 | "maintainer about this event.\n"); |
364 | return -EINVAL; |
365 | } |
366 | len = strlen(buff); |
367 | /* ``echo "secret" > seclvl/passwd'' includes a newline */ |
368 | if (buff[len - 1] == '\n') { |
369 | len--; |
370 | } |
371 | /* Hash the password, then compare the hashed values */ |
372 | if ((rc = plaintext_to_sha1(tmp, buff, len))) { |
373 | seclvl_printk(0, KERN_ERR, "Error hashing password: rc = " |
374 | "[%d]\n", rc); |
375 | return rc; |
376 | } |
377 | for (i = 0; i < SHA1_DIGEST_SIZE; i++) { |
378 | if (hashedPassword[i] != tmp[i]) { |
379 | return -EPERM; |
380 | } |
381 | } |
382 | seclvl_printk(0, KERN_INFO, |
383 | "Password accepted; seclvl reduced to 0.\n"); |
384 | seclvl = 0; |
385 | return count; |
386 | } |
387 | |
388 | /* Generate sysfs_attr_passwd */ |
389 | static struct seclvl_attribute sysfs_attr_passwd = |
390 | __ATTR(passwd, (S_IFREG | S_IRUGO | S_IWUSR), seclvl_read_passwd, |
391 | seclvl_write_passwd); |
392 | |
393 | /** |
394 | * Explicitely disallow ptrace'ing the init process. |
395 | */ |
396 | static int seclvl_ptrace(struct task_struct *parent, struct task_struct *child) |
397 | { |
398 | if (seclvl >= 0) { |
399 | if (child->pid == 1) { |
400 | seclvl_printk(1, KERN_WARNING, "Attempt to ptrace " |
401 | "the init process dissallowed in " |
402 | "secure level %d\n", seclvl); |
403 | return -EPERM; |
404 | } |
405 | } |
406 | return 0; |
407 | } |
408 | |
409 | /** |
410 | * Capability checks for seclvl. The majority of the policy |
411 | * enforcement for seclvl takes place here. |
412 | */ |
413 | static int seclvl_capable(struct task_struct *tsk, int cap) |
414 | { |
415 | /* init can do anything it wants */ |
416 | if (tsk->pid == 1) |
417 | return 0; |
418 | |
419 | switch (seclvl) { |
420 | case 2: |
421 | /* fall through */ |
422 | case 1: |
423 | if (cap == CAP_LINUX_IMMUTABLE) { |
424 | seclvl_printk(1, KERN_WARNING, "Attempt to modify " |
425 | "the IMMUTABLE and/or APPEND extended " |
426 | "attribute on a file with the IMMUTABLE " |
427 | "and/or APPEND extended attribute set " |
428 | "denied in seclvl [%d]\n", seclvl); |
429 | return -EPERM; |
430 | } else if (cap == CAP_SYS_RAWIO) { // Somewhat broad... |
431 | seclvl_printk(1, KERN_WARNING, "Attempt to perform " |
432 | "raw I/O while in secure level [%d] " |
433 | "denied\n", seclvl); |
434 | return -EPERM; |
435 | } else if (cap == CAP_NET_ADMIN) { |
436 | seclvl_printk(1, KERN_WARNING, "Attempt to perform " |
437 | "network administrative task while " |
438 | "in secure level [%d] denied\n", seclvl); |
439 | return -EPERM; |
440 | } else if (cap == CAP_SETUID) { |
441 | seclvl_printk(1, KERN_WARNING, "Attempt to setuid " |
442 | "while in secure level [%d] denied\n", |
443 | seclvl); |
444 | return -EPERM; |
445 | } else if (cap == CAP_SETGID) { |
446 | seclvl_printk(1, KERN_WARNING, "Attempt to setgid " |
447 | "while in secure level [%d] denied\n", |
448 | seclvl); |
449 | } else if (cap == CAP_SYS_MODULE) { |
450 | seclvl_printk(1, KERN_WARNING, "Attempt to perform " |
451 | "a module operation while in secure " |
452 | "level [%d] denied\n", seclvl); |
453 | return -EPERM; |
454 | } |
455 | break; |
456 | default: |
457 | break; |
458 | } |
459 | /* from dummy.c */ |
460 | if (cap_is_fs_cap(cap) ? tsk->fsuid == 0 : tsk->euid == 0) |
461 | return 0; /* capability granted */ |
462 | seclvl_printk(1, KERN_WARNING, "Capability denied\n"); |
463 | return -EPERM; /* capability denied */ |
464 | } |
465 | |
466 | /** |
467 | * Disallow reversing the clock in seclvl > 1 |
468 | */ |
469 | static int seclvl_settime(struct timespec *tv, struct timezone *tz) |
470 | { |
471 | struct timespec now; |
472 | if (seclvl > 1) { |
473 | now = current_kernel_time(); |
474 | if (tv->tv_sec < now.tv_sec || |
475 | (tv->tv_sec == now.tv_sec && tv->tv_nsec < now.tv_nsec)) { |
476 | seclvl_printk(1, KERN_WARNING, "Attempt to decrement " |
477 | "time in secure level %d denied: " |
478 | "current->pid = [%d], " |
479 | "current->group_leader->pid = [%d]\n", |
480 | seclvl, current->pid, |
481 | current->group_leader->pid); |
482 | return -EPERM; |
483 | } /* if attempt to decrement time */ |
484 | } /* if seclvl > 1 */ |
485 | return 0; |
486 | } |
487 | |
488 | /* claim the blockdev to exclude mounters, release on file close */ |
489 | static int seclvl_bd_claim(struct inode *inode) |
490 | { |
491 | int holder; |
492 | struct block_device *bdev = NULL; |
493 | dev_t dev = inode->i_rdev; |
494 | bdev = open_by_devnum(dev, FMODE_WRITE); |
495 | if (bdev) { |
496 | if (bd_claim(bdev, &holder)) { |
497 | blkdev_put(bdev); |
498 | return -EPERM; |
499 | } |
500 | /* claimed, mark it to release on close */ |
501 | inode->i_security = current; |
502 | } |
503 | return 0; |
504 | } |
505 | |
506 | /* release the blockdev if you claimed it */ |
507 | static void seclvl_bd_release(struct inode *inode) |
508 | { |
509 | if (inode && S_ISBLK(inode->i_mode) && inode->i_security == current) { |
510 | struct block_device *bdev = inode->i_bdev; |
511 | if (bdev) { |
512 | bd_release(bdev); |
513 | blkdev_put(bdev); |
514 | inode->i_security = NULL; |
515 | } |
516 | } |
517 | } |
518 | |
519 | /** |
520 | * Security for writes to block devices is regulated by this seclvl |
521 | * function. Deny all writes to block devices in seclvl 2. In |
522 | * seclvl 1, we only deny writes to *mounted* block devices. |
523 | */ |
524 | static int |
525 | seclvl_inode_permission(struct inode *inode, int mask, struct nameidata *nd) |
526 | { |
527 | if (current->pid != 1 && S_ISBLK(inode->i_mode) && (mask & MAY_WRITE)) { |
528 | switch (seclvl) { |
529 | case 2: |
530 | seclvl_printk(1, KERN_WARNING, "Write to block device " |
531 | "denied in secure level [%d]\n", seclvl); |
532 | return -EPERM; |
533 | case 1: |
534 | if (seclvl_bd_claim(inode)) { |
535 | seclvl_printk(1, KERN_WARNING, |
536 | "Write to mounted block device " |
537 | "denied in secure level [%d]\n", |
538 | seclvl); |
539 | return -EPERM; |
540 | } |
541 | } |
542 | } |
543 | return 0; |
544 | } |
545 | |
546 | /** |
547 | * The SUID and SGID bits cannot be set in seclvl >= 1 |
548 | */ |
549 | static int seclvl_inode_setattr(struct dentry *dentry, struct iattr *iattr) |
550 | { |
551 | if (seclvl > 0) { |
552 | if (iattr->ia_valid & ATTR_MODE) |
553 | if (iattr->ia_mode & S_ISUID || |
554 | iattr->ia_mode & S_ISGID) { |
555 | seclvl_printk(1, KERN_WARNING, "Attempt to " |
556 | "modify SUID or SGID bit " |
557 | "denied in seclvl [%d]\n", |
558 | seclvl); |
559 | return -EPERM; |
560 | } |
561 | } |
562 | return 0; |
563 | } |
564 | |
565 | /* release busied block devices */ |
566 | static void seclvl_file_free_security(struct file *filp) |
567 | { |
568 | struct dentry *dentry = filp->f_dentry; |
569 | struct inode *inode = NULL; |
570 | |
571 | if (dentry) { |
572 | inode = dentry->d_inode; |
573 | seclvl_bd_release(inode); |
574 | } |
575 | } |
576 | |
577 | /** |
578 | * Cannot unmount in secure level 2 |
579 | */ |
580 | static int seclvl_umount(struct vfsmount *mnt, int flags) |
581 | { |
582 | if (current->pid == 1) { |
583 | return 0; |
584 | } |
585 | if (seclvl == 2) { |
586 | seclvl_printk(1, KERN_WARNING, "Attempt to unmount in secure " |
587 | "level %d\n", seclvl); |
588 | return -EPERM; |
589 | } |
590 | return 0; |
591 | } |
592 | |
593 | static struct security_operations seclvl_ops = { |
594 | .ptrace = seclvl_ptrace, |
595 | .capable = seclvl_capable, |
596 | .inode_permission = seclvl_inode_permission, |
597 | .inode_setattr = seclvl_inode_setattr, |
598 | .file_free_security = seclvl_file_free_security, |
599 | .settime = seclvl_settime, |
600 | .sb_umount = seclvl_umount, |
601 | }; |
602 | |
603 | /** |
604 | * Process the password-related module parameters |
605 | */ |
606 | static int processPassword(void) |
607 | { |
608 | int rc = 0; |
609 | hashedPassword[0] = '\0'; |
610 | if (*passwd) { |
611 | if (*sha1_passwd) { |
612 | seclvl_printk(0, KERN_ERR, "Error: Both " |
613 | "passwd and sha1_passwd " |
614 | "were set, but they are mutually " |
615 | "exclusive.\n"); |
616 | return -EINVAL; |
617 | } |
618 | if ((rc = plaintext_to_sha1(hashedPassword, passwd, |
619 | strlen(passwd)))) { |
620 | seclvl_printk(0, KERN_ERR, "Error: SHA1 support not " |
621 | "in kernel\n"); |
622 | return rc; |
623 | } |
624 | /* All static data goes to the BSS, which zero's the |
625 | * plaintext password out for us. */ |
626 | } else if (*sha1_passwd) { // Base 16 |
627 | int i; |
628 | i = strlen(sha1_passwd); |
629 | if (i != (SHA1_DIGEST_SIZE * 2)) { |
630 | seclvl_printk(0, KERN_ERR, "Received [%d] bytes; " |
631 | "expected [%d] for the hexadecimal " |
632 | "representation of the SHA1 hash of " |
633 | "the password.\n", |
634 | i, (SHA1_DIGEST_SIZE * 2)); |
635 | return -EINVAL; |
636 | } |
637 | while ((i -= 2) + 2) { |
638 | unsigned char tmp; |
639 | tmp = sha1_passwd[i + 2]; |
640 | sha1_passwd[i + 2] = '\0'; |
641 | hashedPassword[i / 2] = (unsigned char) |
642 | simple_strtol(&sha1_passwd[i], NULL, 16); |
643 | sha1_passwd[i + 2] = tmp; |
644 | } |
645 | } |
646 | return 0; |
647 | } |
648 | |
649 | /** |
650 | * Sysfs registrations |
651 | */ |
652 | static int doSysfsRegistrations(void) |
653 | { |
654 | int rc = 0; |
655 | if ((rc = subsystem_register(&seclvl_subsys))) { |
656 | seclvl_printk(0, KERN_WARNING, |
657 | "Error [%d] registering seclvl subsystem\n", rc); |
658 | return rc; |
659 | } |
660 | sysfs_create_file(&seclvl_subsys.kset.kobj, &sysfs_attr_seclvl.attr); |
661 | if (*passwd || *sha1_passwd) { |
662 | sysfs_create_file(&seclvl_subsys.kset.kobj, |
663 | &sysfs_attr_passwd.attr); |
664 | } |
665 | return 0; |
666 | } |
667 | |
668 | /** |
669 | * Initialize the seclvl module. |
670 | */ |
671 | static int __init seclvl_init(void) |
672 | { |
673 | int rc = 0; |
674 | if (verbosity < 0 || verbosity > 1) { |
675 | printk(KERN_ERR "Error: bad verbosity [%d]; only 0 or 1 " |
676 | "are valid values\n", verbosity); |
677 | rc = -EINVAL; |
678 | goto exit; |
679 | } |
680 | sysfs_attr_seclvl.attr.owner = THIS_MODULE; |
681 | sysfs_attr_passwd.attr.owner = THIS_MODULE; |
682 | if (initlvl < -1 || initlvl > 2) { |
683 | seclvl_printk(0, KERN_ERR, "Error: bad initial securelevel " |
684 | "[%d].\n", initlvl); |
685 | rc = -EINVAL; |
686 | goto exit; |
687 | } |
688 | seclvl = initlvl; |
689 | if ((rc = processPassword())) { |
690 | seclvl_printk(0, KERN_ERR, "Error processing the password " |
691 | "module parameter(s): rc = [%d]\n", rc); |
692 | goto exit; |
693 | } |
694 | /* register ourselves with the security framework */ |
695 | if (register_security(&seclvl_ops)) { |
696 | seclvl_printk(0, KERN_ERR, |
697 | "seclvl: Failure registering with the " |
698 | "kernel.\n"); |
699 | /* try registering with primary module */ |
700 | rc = mod_reg_security(MY_NAME, &seclvl_ops); |
701 | if (rc) { |
702 | seclvl_printk(0, KERN_ERR, "seclvl: Failure " |
703 | "registering with primary security " |
704 | "module.\n"); |
705 | goto exit; |
706 | } /* if primary module registered */ |
707 | secondary = 1; |
708 | } /* if we registered ourselves with the security framework */ |
709 | if ((rc = doSysfsRegistrations())) { |
710 | seclvl_printk(0, KERN_ERR, "Error registering with sysfs\n"); |
711 | goto exit; |
712 | } |
713 | seclvl_printk(0, KERN_INFO, "seclvl: Successfully initialized.\n"); |
714 | exit: |
715 | if (rc) { |
716 | printk(KERN_ERR "seclvl: Error during initialization: rc = " |
717 | "[%d]\n", rc); |
718 | } |
719 | return rc; |
720 | } |
721 | |
722 | /** |
723 | * Remove the seclvl module. |
724 | */ |
725 | static void __exit seclvl_exit(void) |
726 | { |
727 | sysfs_remove_file(&seclvl_subsys.kset.kobj, &sysfs_attr_seclvl.attr); |
728 | if (*passwd || *sha1_passwd) { |
729 | sysfs_remove_file(&seclvl_subsys.kset.kobj, |
730 | &sysfs_attr_passwd.attr); |
731 | } |
732 | subsystem_unregister(&seclvl_subsys); |
733 | if (secondary == 1) { |
734 | mod_unreg_security(MY_NAME, &seclvl_ops); |
735 | } else if (unregister_security(&seclvl_ops)) { |
736 | seclvl_printk(0, KERN_INFO, |
737 | "seclvl: Failure unregistering with the " |
738 | "kernel\n"); |
739 | } |
740 | } |
741 | |
742 | module_init(seclvl_init); |
743 | module_exit(seclvl_exit); |
744 | |
745 | MODULE_AUTHOR("Michael A. Halcrow <mike@halcrow.us>"); |
746 | MODULE_DESCRIPTION("LSM implementation of the BSD Secure Levels"); |
747 | MODULE_LICENSE("GPL"); |