1 /*
2 * NSA Security-Enhanced Linux (SELinux) security module
3 *
4 * This file contains the SELinux hook function implementations.
5 *
6 * Authors: Stephen Smalley, <sds@epoch.ncsc.mil>
7 * Chris Vance, <cvance@nai.com>
8 * Wayne Salamon, <wsalamon@nai.com>
9 * James Morris <jmorris@redhat.com>
10 *
11 * Copyright (C) 2001,2002 Networks Associates Technology, Inc.
12 * Copyright (C) 2003-2008 Red Hat, Inc., James Morris <jmorris@redhat.com>
13 * Eric Paris <eparis@redhat.com>
14 * Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
15 * <dgoeddel@trustedcs.com>
16 * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P.
17 * Paul Moore <paul.moore@hp.com>
18 * Copyright (C) 2007 Hitachi Software Engineering Co., Ltd.
19 * Yuichi Nakamura <ynakam@hitachisoft.jp>
20 *
21 * This program is free software; you can redistribute it and/or modify
22 * it under the terms of the GNU General Public License version 2,
23 * as published by the Free Software Foundation.
24 */
25
26 #include <linux/init.h>
27 #include <linux/kernel.h>
28 #include <linux/tracehook.h>
29 #include <linux/errno.h>
30 #include <linux/sched.h>
31 #include <linux/security.h>
32 #include <linux/xattr.h>
33 #include <linux/capability.h>
34 #include <linux/unistd.h>
35 #include <linux/mm.h>
36 #include <linux/mman.h>
37 #include <linux/slab.h>
38 #include <linux/pagemap.h>
39 #include <linux/swap.h>
40 #include <linux/spinlock.h>
41 #include <linux/syscalls.h>
42 #include <linux/file.h>
43 #include <linux/fdtable.h>
44 #include <linux/namei.h>
45 #include <linux/mount.h>
46 #include <linux/proc_fs.h>
47 #include <linux/netfilter_ipv4.h>
48 #include <linux/netfilter_ipv6.h>
49 #include <linux/tty.h>
50 #include <net/icmp.h>
51 #include <net/ip.h> /* for local_port_range[] */
52 #include <net/tcp.h> /* struct or_callable used in sock_rcv_skb */
53 #include <net/net_namespace.h>
54 #include <net/netlabel.h>
55 #include <linux/uaccess.h>
56 #include <asm/ioctls.h>
57 #include <asm/atomic.h>
58 #include <linux/bitops.h>
59 #include <linux/interrupt.h>
60 #include <linux/netdevice.h> /* for network interface checks */
61 #include <linux/netlink.h>
62 #include <linux/tcp.h>
63 #include <linux/udp.h>
64 #include <linux/dccp.h>
65 #include <linux/quota.h>
66 #include <linux/un.h> /* for Unix socket types */
67 #include <net/af_unix.h> /* for Unix socket types */
68 #include <linux/parser.h>
69 #include <linux/nfs_mount.h>
70 #include <net/ipv6.h>
71 #include <linux/hugetlb.h>
72 #include <linux/personality.h>
73 #include <linux/sysctl.h>
74 #include <linux/audit.h>
75 #include <linux/string.h>
76 #include <linux/selinux.h>
77 #include <linux/mutex.h>
78 #include <linux/posix-timers.h>
79
80 #include "avc.h"
81 #include "objsec.h"
82 #include "netif.h"
83 #include "netnode.h"
84 #include "netport.h"
85 #include "xfrm.h"
86 #include "netlabel.h"
87 #include "audit.h"
88
89 #define XATTR_SELINUX_SUFFIX "selinux"
90 #define XATTR_NAME_SELINUX XATTR_SECURITY_PREFIX XATTR_SELINUX_SUFFIX
91
92 #define NUM_SEL_MNT_OPTS 5
93
94 extern unsigned int policydb_loaded_version;
95 extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm);
96 extern struct security_operations *security_ops;
97
98 /* SECMARK reference count */
99 atomic_t selinux_secmark_refcount = ATOMIC_INIT(0);
100
101 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
102 int selinux_enforcing;
103
104 static int __init enforcing_setup(char *str)
105 {
106 unsigned long enforcing;
107 if (!strict_strtoul(str, 0, &enforcing))
108 selinux_enforcing = enforcing ? 1 : 0;
109 return 1;
110 }
111 __setup("enforcing=", enforcing_setup);
112 #endif
113
114 #ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
115 int selinux_enabled = CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE;
116
117 static int __init selinux_enabled_setup(char *str)
118 {
119 unsigned long enabled;
120 if (!strict_strtoul(str, 0, &enabled))
121 selinux_enabled = enabled ? 1 : 0;
122 return 1;
123 }
124 __setup("selinux=", selinux_enabled_setup);
125 #else
126 int selinux_enabled = 1;
127 #endif
128
129
130 /*
131 * Minimal support for a secondary security module,
132 * just to allow the use of the capability module.
133 */
134 static struct security_operations *secondary_ops;
135
136 /* Lists of inode and superblock security structures initialized
137 before the policy was loaded. */
138 static LIST_HEAD(superblock_security_head);
139 static DEFINE_SPINLOCK(sb_security_lock);
140
141 static struct kmem_cache *sel_inode_cache;
142
143 /**
144 * selinux_secmark_enabled - Check to see if SECMARK is currently enabled
145 *
146 * Description:
147 * This function checks the SECMARK reference counter to see if any SECMARK
148 * targets are currently configured, if the reference counter is greater than
149 * zero SECMARK is considered to be enabled. Returns true (1) if SECMARK is
150 * enabled, false (0) if SECMARK is disabled.
151 *
152 */
153 static int selinux_secmark_enabled(void)
154 {
155 return (atomic_read(&selinux_secmark_refcount) > 0);
156 }
157
158 /*
159 * initialise the security for the init task
160 */
161 static void cred_init_security(void)
162 {
163 struct cred *cred = (struct cred *) current->real_cred;
164 struct task_security_struct *tsec;
165
166 tsec = kzalloc(sizeof(struct task_security_struct), GFP_KERNEL);
167 if (!tsec)
168 panic("SELinux: Failed to initialize initial task.\n");
169
170 tsec->osid = tsec->sid = SECINITSID_KERNEL;
171 cred->security = tsec;
172 }
173
174 /*
175 * get the security ID of a set of credentials
176 */
177 static inline u32 cred_sid(const struct cred *cred)
178 {
179 const struct task_security_struct *tsec;
180
181 tsec = cred->security;
182 return tsec->sid;
183 }
184
185 /*
186 * get the objective security ID of a task
187 */
188 static inline u32 task_sid(const struct task_struct *task)
189 {
190 u32 sid;
191
192 rcu_read_lock();
193 sid = cred_sid(__task_cred(task));
194 rcu_read_unlock();
195 return sid;
196 }
197
198 /*
199 * get the subjective security ID of the current task
200 */
201 static inline u32 current_sid(void)
202 {
203 const struct task_security_struct *tsec = current_cred()->security;
204
205 return tsec->sid;
206 }
207
208 /* Allocate and free functions for each kind of security blob. */
209
210 static int inode_alloc_security(struct inode *inode)
211 {
212 struct inode_security_struct *isec;
213 u32 sid = current_sid();
214
215 isec = kmem_cache_zalloc(sel_inode_cache, GFP_NOFS);
216 if (!isec)
217 return -ENOMEM;
218
219 mutex_init(&isec->lock);
220 INIT_LIST_HEAD(&isec->list);
221 isec->inode = inode;
222 isec->sid = SECINITSID_UNLABELED;
223 isec->sclass = SECCLASS_FILE;
224 isec->task_sid = sid;
225 inode->i_security = isec;
226
227 return 0;
228 }
229
230 static void inode_free_security(struct inode *inode)
231 {
232 struct inode_security_struct *isec = inode->i_security;
233 struct superblock_security_struct *sbsec = inode->i_sb->s_security;
234
235 spin_lock(&sbsec->isec_lock);
236 if (!list_empty(&isec->list))
237 list_del_init(&isec->list);
238 spin_unlock(&sbsec->isec_lock);
239
240 inode->i_security = NULL;
241 kmem_cache_free(sel_inode_cache, isec);
242 }
243
244 static int file_alloc_security(struct file *file)
245 {
246 struct file_security_struct *fsec;
247 u32 sid = current_sid();
248
249 fsec = kzalloc(sizeof(struct file_security_struct), GFP_KERNEL);
250 if (!fsec)
251 return -ENOMEM;
252
253 fsec->sid = sid;
254 fsec->fown_sid = sid;
255 file->f_security = fsec;
256
257 return 0;
258 }
259
260 static void file_free_security(struct file *file)
261 {
262 struct file_security_struct *fsec = file->f_security;
263 file->f_security = NULL;
264 kfree(fsec);
265 }
266
267 static int superblock_alloc_security(struct super_block *sb)
268 {
269 struct superblock_security_struct *sbsec;
270
271 sbsec = kzalloc(sizeof(struct superblock_security_struct), GFP_KERNEL);
272 if (!sbsec)
273 return -ENOMEM;
274
275 mutex_init(&sbsec->lock);
276 INIT_LIST_HEAD(&sbsec->list);
277 INIT_LIST_HEAD(&sbsec->isec_head);
278 spin_lock_init(&sbsec->isec_lock);
279 sbsec->sb = sb;
280 sbsec->sid = SECINITSID_UNLABELED;
281 sbsec->def_sid = SECINITSID_FILE;
282 sbsec->mntpoint_sid = SECINITSID_UNLABELED;
283 sb->s_security = sbsec;
284
285 return 0;
286 }
287
288 static void superblock_free_security(struct super_block *sb)
289 {
290 struct superblock_security_struct *sbsec = sb->s_security;
291
292 spin_lock(&sb_security_lock);
293 if (!list_empty(&sbsec->list))
294 list_del_init(&sbsec->list);
295 spin_unlock(&sb_security_lock);
296
297 sb->s_security = NULL;
298 kfree(sbsec);
299 }
300
301 static int sk_alloc_security(struct sock *sk, int family, gfp_t priority)
302 {
303 struct sk_security_struct *ssec;
304
305 ssec = kzalloc(sizeof(*ssec), priority);
306 if (!ssec)
307 return -ENOMEM;
308
309 ssec->peer_sid = SECINITSID_UNLABELED;
310 ssec->sid = SECINITSID_UNLABELED;
311 sk->sk_security = ssec;
312
313 selinux_netlbl_sk_security_reset(ssec);
314
315 return 0;
316 }
317
318 static void sk_free_security(struct sock *sk)
319 {
320 struct sk_security_struct *ssec = sk->sk_security;
321
322 sk->sk_security = NULL;
323 selinux_netlbl_sk_security_free(ssec);
324 kfree(ssec);
325 }
326
327 /* The security server must be initialized before
328 any labeling or access decisions can be provided. */
329 extern int ss_initialized;
330
331 /* The file system's label must be initialized prior to use. */
332
333 static char *labeling_behaviors[6] = {
334 "uses xattr",
335 "uses transition SIDs",
336 "uses task SIDs",
337 "uses genfs_contexts",
338 "not configured for labeling",
339 "uses mountpoint labeling",
340 };
341
342 static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry);
343
344 static inline int inode_doinit(struct inode *inode)
345 {
346 return inode_doinit_with_dentry(inode, NULL);
347 }
348
349 enum {
350 Opt_error = -1,
351 Opt_context = 1,
352 Opt_fscontext = 2,
353 Opt_defcontext = 3,
354 Opt_rootcontext = 4,
355 Opt_labelsupport = 5,
356 };
357
358 static const match_table_t tokens = {
359 {Opt_context, CONTEXT_STR "%s"},
360 {Opt_fscontext, FSCONTEXT_STR "%s"},
361 {Opt_defcontext, DEFCONTEXT_STR "%s"},
362 {Opt_rootcontext, ROOTCONTEXT_STR "%s"},
363 {Opt_labelsupport, LABELSUPP_STR},
364 {Opt_error, NULL},
365 };
366
367 #define SEL_MOUNT_FAIL_MSG "SELinux: duplicate or incompatible mount options\n"
368
369 static int may_context_mount_sb_relabel(u32 sid,
370 struct superblock_security_struct *sbsec,
371 const struct cred *cred)
372 {
373 const struct task_security_struct *tsec = cred->security;
374 int rc;
375
376 rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
377 FILESYSTEM__RELABELFROM, NULL);
378 if (rc)
379 return rc;
380
381 rc = avc_has_perm(tsec->sid, sid, SECCLASS_FILESYSTEM,
382 FILESYSTEM__RELABELTO, NULL);
383 return rc;
384 }
385
386 static int may_context_mount_inode_relabel(u32 sid,
387 struct superblock_security_struct *sbsec,
388 const struct cred *cred)
389 {
390 const struct task_security_struct *tsec = cred->security;
391 int rc;
392 rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
393 FILESYSTEM__RELABELFROM, NULL);
394 if (rc)
395 return rc;
396
397 rc = avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM,
398 FILESYSTEM__ASSOCIATE, NULL);
399 return rc;
400 }
401
402 static int sb_finish_set_opts(struct super_block *sb)
403 {
404 struct superblock_security_struct *sbsec = sb->s_security;
405 struct dentry *root = sb->s_root;
406 struct inode *root_inode = root->d_inode;
407 int rc = 0;
408
409 if (sbsec->behavior == SECURITY_FS_USE_XATTR) {
410 /* Make sure that the xattr handler exists and that no
411 error other than -ENODATA is returned by getxattr on
412 the root directory. -ENODATA is ok, as this may be
413 the first boot of the SELinux kernel before we have
414 assigned xattr values to the filesystem. */
415 if (!root_inode->i_op->getxattr) {
416 printk(KERN_WARNING "SELinux: (dev %s, type %s) has no "
417 "xattr support\n", sb->s_id, sb->s_type->name);
418 rc = -EOPNOTSUPP;
419 goto out;
420 }
421 rc = root_inode->i_op->getxattr(root, XATTR_NAME_SELINUX, NULL, 0);
422 if (rc < 0 && rc != -ENODATA) {
423 if (rc == -EOPNOTSUPP)
424 printk(KERN_WARNING "SELinux: (dev %s, type "
425 "%s) has no security xattr handler\n",
426 sb->s_id, sb->s_type->name);
427 else
428 printk(KERN_WARNING "SELinux: (dev %s, type "
429 "%s) getxattr errno %d\n", sb->s_id,
430 sb->s_type->name, -rc);
431 goto out;
432 }
433 }
434
435 sbsec->flags |= (SE_SBINITIALIZED | SE_SBLABELSUPP);
436
437 if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
438 printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n",
439 sb->s_id, sb->s_type->name);
440 else
441 printk(KERN_DEBUG "SELinux: initialized (dev %s, type %s), %s\n",
442 sb->s_id, sb->s_type->name,
443 labeling_behaviors[sbsec->behavior-1]);
444
445 if (sbsec->behavior == SECURITY_FS_USE_GENFS ||
446 sbsec->behavior == SECURITY_FS_USE_MNTPOINT ||
447 sbsec->behavior == SECURITY_FS_USE_NONE ||
448 sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
449 sbsec->flags &= ~SE_SBLABELSUPP;
450
451 /* Initialize the root inode. */
452 rc = inode_doinit_with_dentry(root_inode, root);
453
454 /* Initialize any other inodes associated with the superblock, e.g.
455 inodes created prior to initial policy load or inodes created
456 during get_sb by a pseudo filesystem that directly
457 populates itself. */
458 spin_lock(&sbsec->isec_lock);
459 next_inode:
460 if (!list_empty(&sbsec->isec_head)) {
461 struct inode_security_struct *isec =
462 list_entry(sbsec->isec_head.next,
463 struct inode_security_struct, list);
464 struct inode *inode = isec->inode;
465 spin_unlock(&sbsec->isec_lock);
466 inode = igrab(inode);
467 if (inode) {
468 if (!IS_PRIVATE(inode))
469 inode_doinit(inode);
470 iput(inode);
471 }
472 spin_lock(&sbsec->isec_lock);
473 list_del_init(&isec->list);
474 goto next_inode;
475 }
476 spin_unlock(&sbsec->isec_lock);
477 out:
478 return rc;
479 }
480
481 /*
482 * This function should allow an FS to ask what it's mount security
483 * options were so it can use those later for submounts, displaying
484 * mount options, or whatever.
485 */
486 static int selinux_get_mnt_opts(const struct super_block *sb,
487 struct security_mnt_opts *opts)
488 {
489 int rc = 0, i;
490 struct superblock_security_struct *sbsec = sb->s_security;
491 char *context = NULL;
492 u32 len;
493 char tmp;
494
495 security_init_mnt_opts(opts);
496
497 if (!(sbsec->flags & SE_SBINITIALIZED))
498 return -EINVAL;
499
500 if (!ss_initialized)
501 return -EINVAL;
502
503 tmp = sbsec->flags & SE_MNTMASK;
504 /* count the number of mount options for this sb */
505 for (i = 0; i < 8; i++) {
506 if (tmp & 0x01)
507 opts->num_mnt_opts++;
508 tmp >>= 1;
509 }
510 /* Check if the Label support flag is set */
511 if (sbsec->flags & SE_SBLABELSUPP)
512 opts->num_mnt_opts++;
513
514 opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC);
515 if (!opts->mnt_opts) {
516 rc = -ENOMEM;
517 goto out_free;
518 }
519
520 opts->mnt_opts_flags = kcalloc(opts->num_mnt_opts, sizeof(int), GFP_ATOMIC);
521 if (!opts->mnt_opts_flags) {
522 rc = -ENOMEM;
523 goto out_free;
524 }
525
526 i = 0;
527 if (sbsec->flags & FSCONTEXT_MNT) {
528 rc = security_sid_to_context(sbsec->sid, &context, &len);
529 if (rc)
530 goto out_free;
531 opts->mnt_opts[i] = context;
532 opts->mnt_opts_flags[i++] = FSCONTEXT_MNT;
533 }
534 if (sbsec->flags & CONTEXT_MNT) {
535 rc = security_sid_to_context(sbsec->mntpoint_sid, &context, &len);
536 if (rc)
537 goto out_free;
538 opts->mnt_opts[i] = context;
539 opts->mnt_opts_flags[i++] = CONTEXT_MNT;
540 }
541 if (sbsec->flags & DEFCONTEXT_MNT) {
542 rc = security_sid_to_context(sbsec->def_sid, &context, &len);
543 if (rc)
544 goto out_free;
545 opts->mnt_opts[i] = context;
546 opts->mnt_opts_flags[i++] = DEFCONTEXT_MNT;
547 }
548 if (sbsec->flags & ROOTCONTEXT_MNT) {
549 struct inode *root = sbsec->sb->s_root->d_inode;
550 struct inode_security_struct *isec = root->i_security;
551
552 rc = security_sid_to_context(isec->sid, &context, &len);
553 if (rc)
554 goto out_free;
555 opts->mnt_opts[i] = context;
556 opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT;
557 }
558 if (sbsec->flags & SE_SBLABELSUPP) {
559 opts->mnt_opts[i] = NULL;
560 opts->mnt_opts_flags[i++] = SE_SBLABELSUPP;
561 }
562
563 BUG_ON(i != opts->num_mnt_opts);
564
565 return 0;
566
567 out_free:
568 security_free_mnt_opts(opts);
569 return rc;
570 }
571
572 static int bad_option(struct superblock_security_struct *sbsec, char flag,
573 u32 old_sid, u32 new_sid)
574 {
575 char mnt_flags = sbsec->flags & SE_MNTMASK;
576
577 /* check if the old mount command had the same options */
578 if (sbsec->flags & SE_SBINITIALIZED)
579 if (!(sbsec->flags & flag) ||
580 (old_sid != new_sid))
581 return 1;
582
583 /* check if we were passed the same options twice,
584 * aka someone passed context=a,context=b
585 */
586 if (!(sbsec->flags & SE_SBINITIALIZED))
587 if (mnt_flags & flag)
588 return 1;
589 return 0;
590 }
591
592 /*
593 * Allow filesystems with binary mount data to explicitly set mount point
594 * labeling information.
595 */
596 static int selinux_set_mnt_opts(struct super_block *sb,
597 struct security_mnt_opts *opts)
598 {
599 const struct cred *cred = current_cred();
600 int rc = 0, i;
601 struct superblock_security_struct *sbsec = sb->s_security;
602 const char *name = sb->s_type->name;
603 struct inode *inode = sbsec->sb->s_root->d_inode;
604 struct inode_security_struct *root_isec = inode->i_security;
605 u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
606 u32 defcontext_sid = 0;
607 char **mount_options = opts->mnt_opts;
608 int *flags = opts->mnt_opts_flags;
609 int num_opts = opts->num_mnt_opts;
610
611 mutex_lock(&sbsec->lock);
612
613 if (!ss_initialized) {
614 if (!num_opts) {
615 /* Defer initialization until selinux_complete_init,
616 after the initial policy is loaded and the security
617 server is ready to handle calls. */
618 spin_lock(&sb_security_lock);
619 if (list_empty(&sbsec->list))
620 list_add(&sbsec->list, &superblock_security_head);
621 spin_unlock(&sb_security_lock);
622 goto out;
623 }
624 rc = -EINVAL;
625 printk(KERN_WARNING "SELinux: Unable to set superblock options "
626 "before the security server is initialized\n");
627 goto out;
628 }
629
630 /*
631 * Binary mount data FS will come through this function twice. Once
632 * from an explicit call and once from the generic calls from the vfs.
633 * Since the generic VFS calls will not contain any security mount data
634 * we need to skip the double mount verification.
635 *
636 * This does open a hole in which we will not notice if the first
637 * mount using this sb set explict options and a second mount using
638 * this sb does not set any security options. (The first options
639 * will be used for both mounts)
640 */
641 if ((sbsec->flags & SE_SBINITIALIZED) && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
642 && (num_opts == 0))
643 goto out;
644
645 /*
646 * parse the mount options, check if they are valid sids.
647 * also check if someone is trying to mount the same sb more
648 * than once with different security options.
649 */
650 for (i = 0; i < num_opts; i++) {
651 u32 sid;
652
653 if (flags[i] == SE_SBLABELSUPP)
654 continue;
655 rc = security_context_to_sid(mount_options[i],
656 strlen(mount_options[i]), &sid);
657 if (rc) {
658 printk(KERN_WARNING "SELinux: security_context_to_sid"
659 "(%s) failed for (dev %s, type %s) errno=%d\n",
660 mount_options[i], sb->s_id, name, rc);
661 goto out;
662 }
663 switch (flags[i]) {
664 case FSCONTEXT_MNT:
665 fscontext_sid = sid;
666
667 if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
668 fscontext_sid))
669 goto out_double_mount;
670
671 sbsec->flags |= FSCONTEXT_MNT;
672 break;
673 case CONTEXT_MNT:
674 context_sid = sid;
675
676 if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
677 context_sid))
678 goto out_double_mount;
679
680 sbsec->flags |= CONTEXT_MNT;
681 break;
682 case ROOTCONTEXT_MNT:
683 rootcontext_sid = sid;
684
685 if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
686 rootcontext_sid))
687 goto out_double_mount;
688
689 sbsec->flags |= ROOTCONTEXT_MNT;
690
691 break;
692 case DEFCONTEXT_MNT:
693 defcontext_sid = sid;
694
695 if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
696 defcontext_sid))
697 goto out_double_mount;
698
699 sbsec->flags |= DEFCONTEXT_MNT;
700
701 break;
702 default:
703 rc = -EINVAL;
704 goto out;
705 }
706 }
707
708 if (sbsec->flags & SE_SBINITIALIZED) {
709 /* previously mounted with options, but not on this attempt? */
710 if ((sbsec->flags & SE_MNTMASK) && !num_opts)
711 goto out_double_mount;
712 rc = 0;
713 goto out;
714 }
715
716 if (strcmp(sb->s_type->name, "proc") == 0)
717 sbsec->flags |= SE_SBPROC;
718
719 /* Determine the labeling behavior to use for this filesystem type. */
720 rc = security_fs_use((sbsec->flags & SE_SBPROC) ? "proc" : sb->s_type->name, &sbsec->behavior, &sbsec->sid);
721 if (rc) {
722 printk(KERN_WARNING "%s: security_fs_use(%s) returned %d\n",
723 __func__, sb->s_type->name, rc);
724 goto out;
725 }
726
727 /* sets the context of the superblock for the fs being mounted. */
728 if (fscontext_sid) {
729 rc = may_context_mount_sb_relabel(fscontext_sid, sbsec, cred);
730 if (rc)
731 goto out;
732
733 sbsec->sid = fscontext_sid;
734 }
735
736 /*
737 * Switch to using mount point labeling behavior.
738 * sets the label used on all file below the mountpoint, and will set
739 * the superblock context if not already set.
740 */
741 if (context_sid) {
742 if (!fscontext_sid) {
743 rc = may_context_mount_sb_relabel(context_sid, sbsec,
744 cred);
745 if (rc)
746 goto out;
747 sbsec->sid = context_sid;
748 } else {
749 rc = may_context_mount_inode_relabel(context_sid, sbsec,
750 cred);
751 if (rc)
752 goto out;
753 }
754 if (!rootcontext_sid)
755 rootcontext_sid = context_sid;
756
757 sbsec->mntpoint_sid = context_sid;
758 sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
759 }
760
761 if (rootcontext_sid) {
762 rc = may_context_mount_inode_relabel(rootcontext_sid, sbsec,
763 cred);
764 if (rc)
765 goto out;
766
767 root_isec->sid = rootcontext_sid;
768 root_isec->initialized = 1;
769 }
770
771 if (defcontext_sid) {
772 if (sbsec->behavior != SECURITY_FS_USE_XATTR) {
773 rc = -EINVAL;
774 printk(KERN_WARNING "SELinux: defcontext option is "
775 "invalid for this filesystem type\n");
776 goto out;
777 }
778
779 if (defcontext_sid != sbsec->def_sid) {
780 rc = may_context_mount_inode_relabel(defcontext_sid,
781 sbsec, cred);
782 if (rc)
783 goto out;
784 }
785
786 sbsec->def_sid = defcontext_sid;
787 }
788
789 rc = sb_finish_set_opts(sb);
790 out:
791 mutex_unlock(&sbsec->lock);
792 return rc;
793 out_double_mount:
794 rc = -EINVAL;
795 printk(KERN_WARNING "SELinux: mount invalid. Same superblock, different "
796 "security settings for (dev %s, type %s)\n", sb->s_id, name);
797 goto out;
798 }
799
800 static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
801 struct super_block *newsb)
802 {
803 const struct superblock_security_struct *oldsbsec = oldsb->s_security;
804 struct superblock_security_struct *newsbsec = newsb->s_security;
805
806 int set_fscontext = (oldsbsec->flags & FSCONTEXT_MNT);
807 int set_context = (oldsbsec->flags & CONTEXT_MNT);
808 int set_rootcontext = (oldsbsec->flags & ROOTCONTEXT_MNT);
809
810 /*
811 * if the parent was able to be mounted it clearly had no special lsm
812 * mount options. thus we can safely put this sb on the list and deal
813 * with it later
814 */
815 if (!ss_initialized) {
816 spin_lock(&sb_security_lock);
817 if (list_empty(&newsbsec->list))
818 list_add(&newsbsec->list, &superblock_security_head);
819 spin_unlock(&sb_security_lock);
820 return;
821 }
822
823 /* how can we clone if the old one wasn't set up?? */
824 BUG_ON(!(oldsbsec->flags & SE_SBINITIALIZED));
825
826 /* if fs is reusing a sb, just let its options stand... */
827 if (newsbsec->flags & SE_SBINITIALIZED)
828 return;
829
830 mutex_lock(&newsbsec->lock);
831
832 newsbsec->flags = oldsbsec->flags;
833
834 newsbsec->sid = oldsbsec->sid;
835 newsbsec->def_sid = oldsbsec->def_sid;
836 newsbsec->behavior = oldsbsec->behavior;
837
838 if (set_context) {
839 u32 sid = oldsbsec->mntpoint_sid;
840
841 if (!set_fscontext)
842 newsbsec->sid = sid;
843 if (!set_rootcontext) {
844 struct inode *newinode = newsb->s_root->d_inode;
845 struct inode_security_struct *newisec = newinode->i_security;
846 newisec->sid = sid;
847 }
848 newsbsec->mntpoint_sid = sid;
849 }
850 if (set_rootcontext) {
851 const struct inode *oldinode = oldsb->s_root->d_inode;
852 const struct inode_security_struct *oldisec = oldinode->i_security;
853 struct inode *newinode = newsb->s_root->d_inode;
854 struct inode_security_struct *newisec = newinode->i_security;
855
856 newisec->sid = oldisec->sid;
857 }
858
859 sb_finish_set_opts(newsb);
860 mutex_unlock(&newsbsec->lock);
861 }
862
863 static int selinux_parse_opts_str(char *options,
864 struct security_mnt_opts *opts)
865 {
866 char *p;
867 char *context = NULL, *defcontext = NULL;
868 char *fscontext = NULL, *rootcontext = NULL;
869 int rc, num_mnt_opts = 0;
870
871 opts->num_mnt_opts = 0;
872
873 /* Standard string-based options. */
874 while ((p = strsep(&options, "|")) != NULL) {
875 int token;
876 substring_t args[MAX_OPT_ARGS];
877
878 if (!*p)
879 continue;
880
881 token = match_token(p, tokens, args);
882
883 switch (token) {
884 case Opt_context:
885 if (context || defcontext) {
886 rc = -EINVAL;
887 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
888 goto out_err;
889 }
890 context = match_strdup(&args[0]);
891 if (!context) {
892 rc = -ENOMEM;
893 goto out_err;
894 }
895 break;
896
897 case Opt_fscontext:
898 if (fscontext) {
899 rc = -EINVAL;
900 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
901 goto out_err;
902 }
903 fscontext = match_strdup(&args[0]);
904 if (!fscontext) {
905 rc = -ENOMEM;
906 goto out_err;
907 }
908 break;
909
910 case Opt_rootcontext:
911 if (rootcontext) {
912 rc = -EINVAL;
913 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
914 goto out_err;
915 }
916 rootcontext = match_strdup(&args[0]);
917 if (!rootcontext) {
918 rc = -ENOMEM;
919 goto out_err;
920 }
921 break;
922
923 case Opt_defcontext:
924 if (context || defcontext) {
925 rc = -EINVAL;
926 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
927 goto out_err;
928 }
929 defcontext = match_strdup(&args[0]);
930 if (!defcontext) {
931 rc = -ENOMEM;
932 goto out_err;
933 }
934 break;
935 case Opt_labelsupport:
936 break;
937 default:
938 rc = -EINVAL;
939 printk(KERN_WARNING "SELinux: unknown mount option\n");
940 goto out_err;
941
942 }
943 }
944
945 rc = -ENOMEM;
946 opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_ATOMIC);
947 if (!opts->mnt_opts)
948 goto out_err;
949
950 opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int), GFP_ATOMIC);
951 if (!opts->mnt_opts_flags) {
952 kfree(opts->mnt_opts);
953 goto out_err;
954 }
955
956 if (fscontext) {
957 opts->mnt_opts[num_mnt_opts] = fscontext;
958 opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
959 }
960 if (context) {
961 opts->mnt_opts[num_mnt_opts] = context;
962 opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
963 }
964 if (rootcontext) {
965 opts->mnt_opts[num_mnt_opts] = rootcontext;
966 opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
967 }
968 if (defcontext) {
969 opts->mnt_opts[num_mnt_opts] = defcontext;
970 opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
971 }
972
973 opts->num_mnt_opts = num_mnt_opts;
974 return 0;
975
976 out_err:
977 kfree(context);
978 kfree(defcontext);
979 kfree(fscontext);
980 kfree(rootcontext);
981 return rc;
982 }
983 /*
984 * string mount options parsing and call set the sbsec
985 */
986 static int superblock_doinit(struct super_block *sb, void *data)
987 {
988 int rc = 0;
989 char *options = data;
990 struct security_mnt_opts opts;
991
992 security_init_mnt_opts(&opts);
993
994 if (!data)
995 goto out;
996
997 BUG_ON(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA);
998
999 rc = selinux_parse_opts_str(options, &opts);
1000 if (rc)
1001 goto out_err;
1002
1003 out:
1004 rc = selinux_set_mnt_opts(sb, &opts);
1005
1006 out_err:
1007 security_free_mnt_opts(&opts);
1008 return rc;
1009 }
1010
1011 static void selinux_write_opts(struct seq_file *m,
1012 struct security_mnt_opts *opts)
1013 {
1014 int i;
1015 char *prefix;
1016
1017 for (i = 0; i < opts->num_mnt_opts; i++) {
1018 char *has_comma;
1019
1020 if (opts->mnt_opts[i])
1021 has_comma = strchr(opts->mnt_opts[i], ',');
1022 else
1023 has_comma = NULL;
1024
1025 switch (opts->mnt_opts_flags[i]) {
1026 case CONTEXT_MNT:
1027 prefix = CONTEXT_STR;
1028 break;
1029 case FSCONTEXT_MNT:
1030 prefix = FSCONTEXT_STR;
1031 break;
1032 case ROOTCONTEXT_MNT:
1033 prefix = ROOTCONTEXT_STR;
1034 break;
1035 case DEFCONTEXT_MNT:
1036 prefix = DEFCONTEXT_STR;
1037 break;
1038 case SE_SBLABELSUPP:
1039 seq_putc(m, ',');
1040 seq_puts(m, LABELSUPP_STR);
1041 continue;
1042 default:
1043 BUG();
1044 };
1045 /* we need a comma before each option */
1046 seq_putc(m, ',');
1047 seq_puts(m, prefix);
1048 if (has_comma)
1049 seq_putc(m, '\"');
1050 seq_puts(m, opts->mnt_opts[i]);
1051 if (has_comma)
1052 seq_putc(m, '\"');
1053 }
1054 }
1055
1056 static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
1057 {
1058 struct security_mnt_opts opts;
1059 int rc;
1060
1061 rc = selinux_get_mnt_opts(sb, &opts);
1062 if (rc) {
1063 /* before policy load we may get EINVAL, don't show anything */
1064 if (rc == -EINVAL)
1065 rc = 0;
1066 return rc;
1067 }
1068
1069 selinux_write_opts(m, &opts);
1070
1071 security_free_mnt_opts(&opts);
1072
1073 return rc;
1074 }
1075
1076 static inline u16 inode_mode_to_security_class(umode_t mode)
1077 {
1078 switch (mode & S_IFMT) {
1079 case S_IFSOCK:
1080 return SECCLASS_SOCK_FILE;
1081 case S_IFLNK:
1082 return SECCLASS_LNK_FILE;
1083 case S_IFREG:
1084 return SECCLASS_FILE;
1085 case S_IFBLK:
1086 return SECCLASS_BLK_FILE;
1087 case S_IFDIR:
1088 return SECCLASS_DIR;
1089 case S_IFCHR:
1090 return SECCLASS_CHR_FILE;
1091 case S_IFIFO:
1092 return SECCLASS_FIFO_FILE;
1093
1094 }
1095
1096 return SECCLASS_FILE;
1097 }
1098
1099 static inline int default_protocol_stream(int protocol)
1100 {
1101 return (protocol == IPPROTO_IP || protocol == IPPROTO_TCP);
1102 }
1103
1104 static inline int default_protocol_dgram(int protocol)
1105 {
1106 return (protocol == IPPROTO_IP || protocol == IPPROTO_UDP);
1107 }
1108
1109 static inline u16 socket_type_to_security_class(int family, int type, int protocol)
1110 {
1111 switch (family) {
1112 case PF_UNIX:
1113 switch (type) {
1114 case SOCK_STREAM:
1115 case SOCK_SEQPACKET:
1116 return SECCLASS_UNIX_STREAM_SOCKET;
1117 case SOCK_DGRAM:
1118 return SECCLASS_UNIX_DGRAM_SOCKET;
1119 }
1120 break;
1121 case PF_INET:
1122 case PF_INET6:
1123 switch (type) {
1124 case SOCK_STREAM:
1125 if (default_protocol_stream(protocol))
1126 return SECCLASS_TCP_SOCKET;
1127 else
1128 return SECCLASS_RAWIP_SOCKET;
1129 case SOCK_DGRAM:
1130 if (default_protocol_dgram(protocol))
1131 return SECCLASS_UDP_SOCKET;
1132 else
1133 return SECCLASS_RAWIP_SOCKET;
1134 case SOCK_DCCP:
1135 return SECCLASS_DCCP_SOCKET;
1136 default:
1137 return SECCLASS_RAWIP_SOCKET;
1138 }
1139 break;
1140 case PF_NETLINK:
1141 switch (protocol) {
1142 case NETLINK_ROUTE:
1143 return SECCLASS_NETLINK_ROUTE_SOCKET;
1144 case NETLINK_FIREWALL:
1145 return SECCLASS_NETLINK_FIREWALL_SOCKET;
1146 case NETLINK_INET_DIAG:
1147 return SECCLASS_NETLINK_TCPDIAG_SOCKET;
1148 case NETLINK_NFLOG:
1149 return SECCLASS_NETLINK_NFLOG_SOCKET;
1150 case NETLINK_XFRM:
1151 return SECCLASS_NETLINK_XFRM_SOCKET;
1152 case NETLINK_SELINUX:
1153 return SECCLASS_NETLINK_SELINUX_SOCKET;
1154 case NETLINK_AUDIT:
1155 return SECCLASS_NETLINK_AUDIT_SOCKET;
1156 case NETLINK_IP6_FW:
1157 return SECCLASS_NETLINK_IP6FW_SOCKET;
1158 case NETLINK_DNRTMSG:
1159 return SECCLASS_NETLINK_DNRT_SOCKET;
1160 case NETLINK_KOBJECT_UEVENT:
1161 return SECCLASS_NETLINK_KOBJECT_UEVENT_SOCKET;
1162 default:
1163 return SECCLASS_NETLINK_SOCKET;
1164 }
1165 case PF_PACKET:
1166 return SECCLASS_PACKET_SOCKET;
1167 case PF_KEY:
1168 return SECCLASS_KEY_SOCKET;
1169 case PF_APPLETALK:
1170 return SECCLASS_APPLETALK_SOCKET;
1171 }
1172
1173 return SECCLASS_SOCKET;
1174 }
1175
1176 #ifdef CONFIG_PROC_FS
1177 static int selinux_proc_get_sid(struct proc_dir_entry *de,
1178 u16 tclass,
1179 u32 *sid)
1180 {
1181 int buflen, rc;
1182 char *buffer, *path, *end;
1183
1184 buffer = (char *)__get_free_page(GFP_KERNEL);
1185 if (!buffer)
1186 return -ENOMEM;
1187
1188 buflen = PAGE_SIZE;
1189 end = buffer+buflen;
1190 *--end = '\0';
1191 buflen--;
1192 path = end-1;
1193 *path = '/';
1194 while (de && de != de->parent) {
1195 buflen -= de->namelen + 1;
1196 if (buflen < 0)
1197 break;
1198 end -= de->namelen;
1199 memcpy(end, de->name, de->namelen);
1200 *--end = '/';
1201 path = end;
1202 de = de->parent;
1203 }
1204 rc = security_genfs_sid("proc", path, tclass, sid);
1205 free_page((unsigned long)buffer);
1206 return rc;
1207 }
1208 #else
1209 static int selinux_proc_get_sid(struct proc_dir_entry *de,
1210 u16 tclass,
1211 u32 *sid)
1212 {
1213 return -EINVAL;
1214 }
1215 #endif
1216
1217 /* The inode's security attributes must be initialized before first use. */
1218 static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry)
1219 {
1220 struct superblock_security_struct *sbsec = NULL;
1221 struct inode_security_struct *isec = inode->i_security;
1222 u32 sid;
1223 struct dentry *dentry;
1224 #define INITCONTEXTLEN 255
1225 char *context = NULL;
1226 unsigned len = 0;
1227 int rc = 0;
1228
1229 if (isec->initialized)
1230 goto out;
1231
1232 mutex_lock(&isec->lock);
1233 if (isec->initialized)
1234 goto out_unlock;
1235
1236 sbsec = inode->i_sb->s_security;
1237 if (!(sbsec->flags & SE_SBINITIALIZED)) {
1238 /* Defer initialization until selinux_complete_init,
1239 after the initial policy is loaded and the security
1240 server is ready to handle calls. */
1241 spin_lock(&sbsec->isec_lock);
1242 if (list_empty(&isec->list))
1243 list_add(&isec->list, &sbsec->isec_head);
1244 spin_unlock(&sbsec->isec_lock);
1245 goto out_unlock;
1246 }
1247
1248 switch (sbsec->behavior) {
1249 case SECURITY_FS_USE_XATTR:
1250 if (!inode->i_op->getxattr) {
1251 isec->sid = sbsec->def_sid;
1252 break;
1253 }
1254
1255 /* Need a dentry, since the xattr API requires one.
1256 Life would be simpler if we could just pass the inode. */
1257 if (opt_dentry) {
1258 /* Called from d_instantiate or d_splice_alias. */
1259 dentry = dget(opt_dentry);
1260 } else {
1261 /* Called from selinux_complete_init, try to find a dentry. */
1262 dentry = d_find_alias(inode);
1263 }
1264 if (!dentry) {
1265 /*
1266 * this is can be hit on boot when a file is accessed
1267 * before the policy is loaded. When we load policy we
1268 * may find inodes that have no dentry on the
1269 * sbsec->isec_head list. No reason to complain as these
1270 * will get fixed up the next time we go through
1271 * inode_doinit with a dentry, before these inodes could
1272 * be used again by userspace.
1273 */
1274 goto out_unlock;
1275 }
1276
1277 len = INITCONTEXTLEN;
1278 context = kmalloc(len+1, GFP_NOFS);
1279 if (!context) {
1280 rc = -ENOMEM;
1281 dput(dentry);
1282 goto out_unlock;
1283 }
1284 context[len] = '\0';
1285 rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
1286 context, len);
1287 if (rc == -ERANGE) {
1288 kfree(context);
1289
1290 /* Need a larger buffer. Query for the right size. */
1291 rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
1292 NULL, 0);
1293 if (rc < 0) {
1294 dput(dentry);
1295 goto out_unlock;
1296 }
1297 len = rc;
1298 context = kmalloc(len+1, GFP_NOFS);
1299 if (!context) {
1300 rc = -ENOMEM;
1301 dput(dentry);
1302 goto out_unlock;
1303 }
1304 context[len] = '\0';
1305 rc = inode->i_op->getxattr(dentry,
1306 XATTR_NAME_SELINUX,
1307 context, len);
1308 }
1309 dput(dentry);
1310 if (rc < 0) {
1311 if (rc != -ENODATA) {
1312 printk(KERN_WARNING "SELinux: %s: getxattr returned "
1313 "%d for dev=%s ino=%ld\n", __func__,
1314 -rc, inode->i_sb->s_id, inode->i_ino);
1315 kfree(context);
1316 goto out_unlock;
1317 }
1318 /* Map ENODATA to the default file SID */
1319 sid = sbsec->def_sid;
1320 rc = 0;
1321 } else {
1322 rc = security_context_to_sid_default(context, rc, &sid,
1323 sbsec->def_sid,
1324 GFP_NOFS);
1325 if (rc) {
1326 char *dev = inode->i_sb->s_id;
1327 unsigned long ino = inode->i_ino;
1328
1329 if (rc == -EINVAL) {
1330 if (printk_ratelimit())
1331 printk(KERN_NOTICE "SELinux: inode=%lu on dev=%s was found to have an invalid "
1332 "context=%s. This indicates you may need to relabel the inode or the "
1333 "filesystem in question.\n", ino, dev, context);
1334 } else {
1335 printk(KERN_WARNING "SELinux: %s: context_to_sid(%s) "
1336 "returned %d for dev=%s ino=%ld\n",
1337 __func__, context, -rc, dev, ino);
1338 }
1339 kfree(context);
1340 /* Leave with the unlabeled SID */
1341 rc = 0;
1342 break;
1343 }
1344 }
1345 kfree(context);
1346 isec->sid = sid;
1347 break;
1348 case SECURITY_FS_USE_TASK:
1349 isec->sid = isec->task_sid;
1350 break;
1351 case SECURITY_FS_USE_TRANS:
1352 /* Default to the fs SID. */
1353 isec->sid = sbsec->sid;
1354
1355 /* Try to obtain a transition SID. */
1356 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1357 rc = security_transition_sid(isec->task_sid,
1358 sbsec->sid,
1359 isec->sclass,
1360 &sid);
1361 if (rc)
1362 goto out_unlock;
1363 isec->sid = sid;
1364 break;
1365 case SECURITY_FS_USE_MNTPOINT:
1366 isec->sid = sbsec->mntpoint_sid;
1367 break;
1368 default:
1369 /* Default to the fs superblock SID. */
1370 isec->sid = sbsec->sid;
1371
1372 if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) {
1373 struct proc_inode *proci = PROC_I(inode);
1374 if (proci->pde) {
1375 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1376 rc = selinux_proc_get_sid(proci->pde,
1377 isec->sclass,
1378 &sid);
1379 if (rc)
1380 goto out_unlock;
1381 isec->sid = sid;
1382 }
1383 }
1384 break;
1385 }
1386
1387 isec->initialized = 1;
1388
1389 out_unlock:
1390 mutex_unlock(&isec->lock);
1391 out:
1392 if (isec->sclass == SECCLASS_FILE)
1393 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1394 return rc;
1395 }
1396
1397 /* Convert a Linux signal to an access vector. */
1398 static inline u32 signal_to_av(int sig)
1399 {
1400 u32 perm = 0;
1401
1402 switch (sig) {
1403 case SIGCHLD:
1404 /* Commonly granted from child to parent. */
1405 perm = PROCESS__SIGCHLD;
1406 break;
1407 case SIGKILL:
1408 /* Cannot be caught or ignored */
1409 perm = PROCESS__SIGKILL;
1410 break;
1411 case SIGSTOP:
1412 /* Cannot be caught or ignored */
1413 perm = PROCESS__SIGSTOP;
1414 break;
1415 default:
1416 /* All other signals. */
1417 perm = PROCESS__SIGNAL;
1418 break;
1419 }
1420
1421 return perm;
1422 }
1423
1424 /*
1425 * Check permission between a pair of credentials
1426 * fork check, ptrace check, etc.
1427 */
1428 static int cred_has_perm(const struct cred *actor,
1429 const struct cred *target,
1430 u32 perms)
1431 {
1432 u32 asid = cred_sid(actor), tsid = cred_sid(target);
1433
1434 return avc_has_perm(asid, tsid, SECCLASS_PROCESS, perms, NULL);
1435 }
1436
1437 /*
1438 * Check permission between a pair of tasks, e.g. signal checks,
1439 * fork check, ptrace check, etc.
1440 * tsk1 is the actor and tsk2 is the target
1441 * - this uses the default subjective creds of tsk1
1442 */
1443 static int task_has_perm(const struct task_struct *tsk1,
1444 const struct task_struct *tsk2,
1445 u32 perms)
1446 {
1447 const struct task_security_struct *__tsec1, *__tsec2;
1448 u32 sid1, sid2;
1449
1450 rcu_read_lock();
1451 __tsec1 = __task_cred(tsk1)->security; sid1 = __tsec1->sid;
1452 __tsec2 = __task_cred(tsk2)->security; sid2 = __tsec2->sid;
1453 rcu_read_unlock();
1454 return avc_has_perm(sid1, sid2, SECCLASS_PROCESS, perms, NULL);
1455 }
1456
1457 /*
1458 * Check permission between current and another task, e.g. signal checks,
1459 * fork check, ptrace check, etc.
1460 * current is the actor and tsk2 is the target
1461 * - this uses current's subjective creds
1462 */
1463 static int current_has_perm(const struct task_struct *tsk,
1464 u32 perms)
1465 {
1466 u32 sid, tsid;
1467
1468 sid = current_sid();
1469 tsid = task_sid(tsk);
1470 return avc_has_perm(sid, tsid, SECCLASS_PROCESS, perms, NULL);
1471 }
1472
1473 #if CAP_LAST_CAP > 63
1474 #error Fix SELinux to handle capabilities > 63.
1475 #endif
1476
1477 /* Check whether a task is allowed to use a capability. */
1478 static int task_has_capability(struct task_struct *tsk,
1479 const struct cred *cred,
1480 int cap, int audit)
1481 {
1482 struct avc_audit_data ad;
1483 struct av_decision avd;
1484 u16 sclass;
1485 u32 sid = cred_sid(cred);
1486 u32 av = CAP_TO_MASK(cap);
1487 int rc;
1488
1489 AVC_AUDIT_DATA_INIT(&ad, CAP);
1490 ad.tsk = tsk;
1491 ad.u.cap = cap;
1492
1493 switch (CAP_TO_INDEX(cap)) {
1494 case 0:
1495 sclass = SECCLASS_CAPABILITY;
1496 break;
1497 case 1:
1498 sclass = SECCLASS_CAPABILITY2;
1499 break;
1500 default:
1501 printk(KERN_ERR
1502 "SELinux: out of range capability %d\n", cap);
1503 BUG();
1504 }
1505
1506 rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);
1507 if (audit == SECURITY_CAP_AUDIT)
1508 avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
1509 return rc;
1510 }
1511
1512 /* Check whether a task is allowed to use a system operation. */
1513 static int task_has_system(struct task_struct *tsk,
1514 u32 perms)
1515 {
1516 u32 sid = task_sid(tsk);
1517
1518 return avc_has_perm(sid, SECINITSID_KERNEL,
1519 SECCLASS_SYSTEM, perms, NULL);
1520 }
1521
1522 /* Check whether a task has a particular permission to an inode.
1523 The 'adp' parameter is optional and allows other audit
1524 data to be passed (e.g. the dentry). */
1525 static int inode_has_perm(const struct cred *cred,
1526 struct inode *inode,
1527 u32 perms,
1528 struct avc_audit_data *adp)
1529 {
1530 struct inode_security_struct *isec;
1531 struct avc_audit_data ad;
1532 u32 sid;
1533
1534 if (unlikely(IS_PRIVATE(inode)))
1535 return 0;
1536
1537 sid = cred_sid(cred);
1538 isec = inode->i_security;
1539
1540 if (!adp) {
1541 adp = &ad;
1542 AVC_AUDIT_DATA_INIT(&ad, FS);
1543 ad.u.fs.inode = inode;
1544 }
1545
1546 return avc_has_perm(sid, isec->sid, isec->sclass, perms, adp);
1547 }
1548
1549 /* Same as inode_has_perm, but pass explicit audit data containing
1550 the dentry to help the auditing code to more easily generate the
1551 pathname if needed. */
1552 static inline int dentry_has_perm(const struct cred *cred,
1553 struct vfsmount *mnt,
1554 struct dentry *dentry,
1555 u32 av)
1556 {
1557 struct inode *inode = dentry->d_inode;
1558 struct avc_audit_data ad;
1559
1560 AVC_AUDIT_DATA_INIT(&ad, FS);
1561 ad.u.fs.path.mnt = mnt;
1562 ad.u.fs.path.dentry = dentry;
1563 return inode_has_perm(cred, inode, av, &ad);
1564 }
1565
1566 /* Check whether a task can use an open file descriptor to
1567 access an inode in a given way. Check access to the
1568 descriptor itself, and then use dentry_has_perm to
1569 check a particular permission to the file.
1570 Access to the descriptor is implicitly granted if it
1571 has the same SID as the process. If av is zero, then
1572 access to the file is not checked, e.g. for cases
1573 where only the descriptor is affected like seek. */
1574 static int file_has_perm(const struct cred *cred,
1575 struct file *file,
1576 u32 av)
1577 {
1578 struct file_security_struct *fsec = file->f_security;
1579 struct inode *inode = file->f_path.dentry->d_inode;
1580 struct avc_audit_data ad;
1581 u32 sid = cred_sid(cred);
1582 int rc;
1583
1584 AVC_AUDIT_DATA_INIT(&ad, FS);
1585 ad.u.fs.path = file->f_path;
1586
1587 if (sid != fsec->sid) {
1588 rc = avc_has_perm(sid, fsec->sid,
1589 SECCLASS_FD,
1590 FD__USE,
1591 &ad);
1592 if (rc)
1593 goto out;
1594 }
1595
1596 /* av is zero if only checking access to the descriptor. */
1597 rc = 0;
1598 if (av)
1599 rc = inode_has_perm(cred, inode, av, &ad);
1600
1601 out:
1602 return rc;
1603 }
1604
1605 /* Check whether a task can create a file. */
1606 static int may_create(struct inode *dir,
1607 struct dentry *dentry,
1608 u16 tclass)
1609 {
1610 const struct cred *cred = current_cred();
1611 const struct task_security_struct *tsec = cred->security;
1612 struct inode_security_struct *dsec;
1613 struct superblock_security_struct *sbsec;
1614 u32 sid, newsid;
1615 struct avc_audit_data ad;
1616 int rc;
1617
1618 dsec = dir->i_security;
1619 sbsec = dir->i_sb->s_security;
1620
1621 sid = tsec->sid;
1622 newsid = tsec->create_sid;
1623
1624 AVC_AUDIT_DATA_INIT(&ad, FS);
1625 ad.u.fs.path.dentry = dentry;
1626
1627 rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR,
1628 DIR__ADD_NAME | DIR__SEARCH,
1629 &ad);
1630 if (rc)
1631 return rc;
1632
1633 if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) {
1634 rc = security_transition_sid(sid, dsec->sid, tclass, &newsid);
1635 if (rc)
1636 return rc;
1637 }
1638
1639 rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad);
1640 if (rc)
1641 return rc;
1642
1643 return avc_has_perm(newsid, sbsec->sid,
1644 SECCLASS_FILESYSTEM,
1645 FILESYSTEM__ASSOCIATE, &ad);
1646 }
1647
1648 /* Check whether a task can create a key. */
1649 static int may_create_key(u32 ksid,
1650 struct task_struct *ctx)
1651 {
1652 u32 sid = task_sid(ctx);
1653
1654 return avc_has_perm(sid, ksid, SECCLASS_KEY, KEY__CREATE, NULL);
1655 }
1656
1657 #define MAY_LINK 0
1658 #define MAY_UNLINK 1
1659 #define MAY_RMDIR 2
1660
1661 /* Check whether a task can link, unlink, or rmdir a file/directory. */
1662 static int may_link(struct inode *dir,
1663 struct dentry *dentry,
1664 int kind)
1665
1666 {
1667 struct inode_security_struct *dsec, *isec;
1668 struct avc_audit_data ad;
1669 u32 sid = current_sid();
1670 u32 av;
1671 int rc;
1672
1673 dsec = dir->i_security;
1674 isec = dentry->d_inode->i_security;
1675
1676 AVC_AUDIT_DATA_INIT(&ad, FS);
1677 ad.u.fs.path.dentry = dentry;
1678
1679 av = DIR__SEARCH;
1680 av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME);
1681 rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR, av, &ad);
1682 if (rc)
1683 return rc;
1684
1685 switch (kind) {
1686 case MAY_LINK:
1687 av = FILE__LINK;
1688 break;
1689 case MAY_UNLINK:
1690 av = FILE__UNLINK;
1691 break;
1692 case MAY_RMDIR:
1693 av = DIR__RMDIR;
1694 break;
1695 default:
1696 printk(KERN_WARNING "SELinux: %s: unrecognized kind %d\n",
1697 __func__, kind);
1698 return 0;
1699 }
1700
1701 rc = avc_has_perm(sid, isec->sid, isec->sclass, av, &ad);
1702 return rc;
1703 }
1704
1705 static inline int may_rename(struct inode *old_dir,
1706 struct dentry *old_dentry,
1707 struct inode *new_dir,
1708 struct dentry *new_dentry)
1709 {
1710 struct inode_security_struct *old_dsec, *new_dsec, *old_isec, *new_isec;
1711 struct avc_audit_data ad;
1712 u32 sid = current_sid();
1713 u32 av;
1714 int old_is_dir, new_is_dir;
1715 int rc;
1716
1717 old_dsec = old_dir->i_security;
1718 old_isec = old_dentry->d_inode->i_security;
1719 old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
1720 new_dsec = new_dir->i_security;
1721
1722 AVC_AUDIT_DATA_INIT(&ad, FS);
1723
1724 ad.u.fs.path.dentry = old_dentry;
1725 rc = avc_has_perm(sid, old_dsec->sid, SECCLASS_DIR,
1726 DIR__REMOVE_NAME | DIR__SEARCH, &ad);
1727 if (rc)
1728 return rc;
1729 rc = avc_has_perm(sid, old_isec->sid,
1730 old_isec->sclass, FILE__RENAME, &ad);
1731 if (rc)
1732 return rc;
1733 if (old_is_dir && new_dir != old_dir) {
1734 rc = avc_has_perm(sid, old_isec->sid,
1735 old_isec->sclass, DIR__REPARENT, &ad);
1736 if (rc)
1737 return rc;
1738 }
1739
1740 ad.u.fs.path.dentry = new_dentry;
1741 av = DIR__ADD_NAME | DIR__SEARCH;
1742 if (new_dentry->d_inode)
1743 av |= DIR__REMOVE_NAME;
1744 rc = avc_has_perm(sid, new_dsec->sid, SECCLASS_DIR, av, &ad);
1745 if (rc)
1746 return rc;
1747 if (new_dentry->d_inode) {
1748 new_isec = new_dentry->d_inode->i_security;
1749 new_is_dir = S_ISDIR(new_dentry->d_inode->i_mode);
1750 rc = avc_has_perm(sid, new_isec->sid,
1751 new_isec->sclass,
1752 (new_is_dir ? DIR__RMDIR : FILE__UNLINK), &ad);
1753 if (rc)
1754 return rc;
1755 }
1756
1757 return 0;
1758 }
1759
1760 /* Check whether a task can perform a filesystem operation. */
1761 static int superblock_has_perm(const struct cred *cred,
1762 struct super_block *sb,
1763 u32 perms,
1764 struct avc_audit_data *ad)
1765 {
1766 struct superblock_security_struct *sbsec;
1767 u32 sid = cred_sid(cred);
1768
1769 sbsec = sb->s_security;
1770 return avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM, perms, ad);
1771 }
1772
1773 /* Convert a Linux mode and permission mask to an access vector. */
1774 static inline u32 file_mask_to_av(int mode, int mask)
1775 {
1776 u32 av = 0;
1777
1778 if ((mode & S_IFMT) != S_IFDIR) {
1779 if (mask & MAY_EXEC)
1780 av |= FILE__EXECUTE;
1781 if (mask & MAY_READ)
1782 av |= FILE__READ;
1783
1784 if (mask & MAY_APPEND)
1785 av |= FILE__APPEND;
1786 else if (mask & MAY_WRITE)
1787 av |= FILE__WRITE;
1788
1789 } else {
1790 if (mask & MAY_EXEC)
1791 av |= DIR__SEARCH;
1792 if (mask & MAY_WRITE)
1793 av |= DIR__WRITE;
1794 if (mask & MAY_READ)
1795 av |= DIR__READ;
1796 }
1797
1798 return av;
1799 }
1800
1801 /* Convert a Linux file to an access vector. */
1802 static inline u32 file_to_av(struct file *file)
1803 {
1804 u32 av = 0;
1805
1806 if (file->f_mode & FMODE_READ)
1807 av |= FILE__READ;
1808 if (file->f_mode & FMODE_WRITE) {
1809 if (file->f_flags & O_APPEND)
1810 av |= FILE__APPEND;
1811 else
1812 av |= FILE__WRITE;
1813 }
1814 if (!av) {
1815 /*
1816 * Special file opened with flags 3 for ioctl-only use.
1817 */
1818 av = FILE__IOCTL;
1819 }
1820
1821 return av;
1822 }
1823
1824 /*
1825 * Convert a file to an access vector and include the correct open
1826 * open permission.
1827 */
1828 static inline u32 open_file_to_av(struct file *file)
1829 {
1830 u32 av = file_to_av(file);
1831
1832 if (selinux_policycap_openperm) {
1833 mode_t mode = file->f_path.dentry->d_inode->i_mode;
1834 /*
1835 * lnk files and socks do not really have an 'open'
1836 */
1837 if (S_ISREG(mode))
1838 av |= FILE__OPEN;
1839 else if (S_ISCHR(mode))
1840 av |= CHR_FILE__OPEN;
1841 else if (S_ISBLK(mode))
1842 av |= BLK_FILE__OPEN;
1843 else if (S_ISFIFO(mode))
1844 av |= FIFO_FILE__OPEN;
1845 else if (S_ISDIR(mode))
1846 av |= DIR__OPEN;
1847 else if (S_ISSOCK(mode))
1848 av |= SOCK_FILE__OPEN;
1849 else
1850 printk(KERN_ERR "SELinux: WARNING: inside %s with "
1851 "unknown mode:%o\n", __func__, mode);
1852 }
1853 return av;
1854 }
1855
1856 /* Hook functions begin here. */
1857
1858 static int selinux_ptrace_may_access(struct task_struct *child,
1859 unsigned int mode)
1860 {
1861 int rc;
1862
1863 rc = cap_ptrace_may_access(child, mode);
1864 if (rc)
1865 return rc;
1866
1867 if (mode == PTRACE_MODE_READ) {
1868 u32 sid = current_sid();
1869 u32 csid = task_sid(child);
1870 return avc_has_perm(sid, csid, SECCLASS_FILE, FILE__READ, NULL);
1871 }
1872
1873 return current_has_perm(child, PROCESS__PTRACE);
1874 }
1875
1876 static int selinux_ptrace_traceme(struct task_struct *parent)
1877 {
1878 int rc;
1879
1880 rc = cap_ptrace_traceme(parent);
1881 if (rc)
1882 return rc;
1883
1884 return task_has_perm(parent, current, PROCESS__PTRACE);
1885 }
1886
1887 static int selinux_capget(struct task_struct *target, kernel_cap_t *effective,
1888 kernel_cap_t *inheritable, kernel_cap_t *permitted)
1889 {
1890 int error;
1891
1892 error = current_has_perm(target, PROCESS__GETCAP);
1893 if (error)
1894 return error;
1895
1896 return cap_capget(target, effective, inheritable, permitted);
1897 }
1898
1899 static int selinux_capset(struct cred *new, const struct cred *old,
1900 const kernel_cap_t *effective,
1901 const kernel_cap_t *inheritable,
1902 const kernel_cap_t *permitted)
1903 {
1904 int error;
1905
1906 error = cap_capset(new, old,
1907 effective, inheritable, permitted);
1908 if (error)
1909 return error;
1910
1911 return cred_has_perm(old, new, PROCESS__SETCAP);
1912 }
1913
1914 /*
1915 * (This comment used to live with the selinux_task_setuid hook,
1916 * which was removed).
1917 *
1918 * Since setuid only affects the current process, and since the SELinux
1919 * controls are not based on the Linux identity attributes, SELinux does not
1920 * need to control this operation. However, SELinux does control the use of
1921 * the CAP_SETUID and CAP_SETGID capabilities using the capable hook.
1922 */
1923
1924 static int selinux_capable(struct task_struct *tsk, const struct cred *cred,
1925 int cap, int audit)
1926 {
1927 int rc;
1928
1929 rc = cap_capable(tsk, cred, cap, audit);
1930 if (rc)
1931 return rc;
1932
1933 return task_has_capability(tsk, cred, cap, audit);
1934 }
1935
1936 static int selinux_sysctl_get_sid(ctl_table *table, u16 tclass, u32 *sid)
1937 {
1938 int buflen, rc;
1939 char *buffer, *path, *end;
1940
1941 rc = -ENOMEM;
1942 buffer = (char *)__get_free_page(GFP_KERNEL);
1943 if (!buffer)
1944 goto out;
1945
1946 buflen = PAGE_SIZE;
1947 end = buffer+buflen;
1948 *--end = '\0';
1949 buflen--;
1950 path = end-1;
1951 *path = '/';
1952 while (table) {
1953 const char *name = table->procname;
1954 size_t namelen = strlen(name);
1955 buflen -= namelen + 1;
1956 if (buflen < 0)
1957 goto out_free;
1958 end -= namelen;
1959 memcpy(end, name, namelen);
1960 *--end = '/';
1961 path = end;
1962 table = table->parent;
1963 }
1964 buflen -= 4;
1965 if (buflen < 0)
1966 goto out_free;
1967 end -= 4;
1968 memcpy(end, "/sys", 4);
1969 path = end;
1970 rc = security_genfs_sid("proc", path, tclass, sid);
1971 out_free:
1972 free_page((unsigned long)buffer);
1973 out:
1974 return rc;
1975 }
1976
1977 static int selinux_sysctl(ctl_table *table, int op)
1978 {
1979 int error = 0;
1980 u32 av;
1981 u32 tsid, sid;
1982 int rc;
1983
1984 sid = current_sid();
1985
1986 rc = selinux_sysctl_get_sid(table, (op == 0001) ?
1987 SECCLASS_DIR : SECCLASS_FILE, &tsid);
1988 if (rc) {
1989 /* Default to the well-defined sysctl SID. */
1990 tsid = SECINITSID_SYSCTL;
1991 }
1992
1993 /* The op values are "defined" in sysctl.c, thereby creating
1994 * a bad coupling between this module and sysctl.c */
1995 if (op == 001) {
1996 error = avc_has_perm(sid, tsid,
1997 SECCLASS_DIR, DIR__SEARCH, NULL);
1998 } else {
1999 av = 0;
2000 if (op & 004)
2001 av |= FILE__READ;
2002 if (op & 002)
2003 av |= FILE__WRITE;
2004 if (av)
2005 error = avc_has_perm(sid, tsid,
2006 SECCLASS_FILE, av, NULL);
2007 }
2008
2009 return error;
2010 }
2011
2012 static int selinux_quotactl(int cmds, int type, int id, struct super_block *sb)
2013 {
2014 const struct cred *cred = current_cred();
2015 int rc = 0;
2016
2017 if (!sb)
2018 return 0;
2019
2020 switch (cmds) {
2021 case Q_SYNC:
2022 case Q_QUOTAON:
2023 case Q_QUOTAOFF:
2024 case Q_SETINFO:
2025 case Q_SETQUOTA:
2026 rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAMOD, NULL);
2027 break;
2028 case Q_GETFMT:
2029 case Q_GETINFO:
2030 case Q_GETQUOTA:
2031 rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAGET, NULL);
2032 break;
2033 default:
2034 rc = 0; /* let the kernel handle invalid cmds */
2035 break;
2036 }
2037 return rc;
2038 }
2039
2040 static int selinux_quota_on(struct dentry *dentry)
2041 {
2042 const struct cred *cred = current_cred();
2043
2044 return dentry_has_perm(cred, NULL, dentry, FILE__QUOTAON);
2045 }
2046
2047 static int selinux_syslog(int type)
2048 {
2049 int rc;
2050
2051 rc = cap_syslog(type);
2052 if (rc)
2053 return rc;
2054
2055 switch (type) {
2056 case 3: /* Read last kernel messages */
2057 case 10: /* Return size of the log buffer */
2058 rc = task_has_system(current, SYSTEM__SYSLOG_READ);
2059 break;
2060 case 6: /* Disable logging to console */
2061 case 7: /* Enable logging to console */
2062 case 8: /* Set level of messages printed to console */
2063 rc = task_has_system(current, SYSTEM__SYSLOG_CONSOLE);
2064 break;
2065 case 0: /* Close log */
2066 case 1: /* Open log */
2067 case 2: /* Read from log */
2068 case 4: /* Read/clear last kernel messages */
2069 case 5: /* Clear ring buffer */
2070 default:
2071 rc = task_has_system(current, SYSTEM__SYSLOG_MOD);
2072 break;
2073 }
2074 return rc;
2075 }
2076
2077 /*
2078 * Check that a process has enough memory to allocate a new virtual
2079 * mapping. 0 means there is enough memory for the allocation to
2080 * succeed and -ENOMEM implies there is not.
2081 *
2082 * Do not audit the selinux permission check, as this is applied to all
2083 * processes that allocate mappings.
2084 */
2085 static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
2086 {
2087 int rc, cap_sys_admin = 0;
2088
2089 rc = selinux_capable(current, current_cred(), CAP_SYS_ADMIN,
2090 SECURITY_CAP_NOAUDIT);
2091 if (rc == 0)
2092 cap_sys_admin = 1;
2093
2094 return __vm_enough_memory(mm, pages, cap_sys_admin);
2095 }
2096
2097 /* binprm security operations */
2098
2099 static int selinux_bprm_set_creds(struct linux_binprm *bprm)
2100 {
2101 const struct task_security_struct *old_tsec;
2102 struct task_security_struct *new_tsec;
2103 struct inode_security_struct *isec;
2104 struct avc_audit_data ad;
2105 struct inode *inode = bprm->file->f_path.dentry->d_inode;
2106 int rc;
2107
2108 rc = cap_bprm_set_creds(bprm);
2109 if (rc)
2110 return rc;
2111
2112 /* SELinux context only depends on initial program or script and not
2113 * the script interpreter */
2114 if (bprm->cred_prepared)
2115 return 0;
2116
2117 old_tsec = current_security();
2118 new_tsec = bprm->cred->security;
2119 isec = inode->i_security;
2120
2121 /* Default to the current task SID. */
2122 new_tsec->sid = old_tsec->sid;
2123 new_tsec->osid = old_tsec->sid;
2124
2125 /* Reset fs, key, and sock SIDs on execve. */
2126 new_tsec->create_sid = 0;
2127 new_tsec->keycreate_sid = 0;
2128 new_tsec->sockcreate_sid = 0;
2129
2130 if (old_tsec->exec_sid) {
2131 new_tsec->sid = old_tsec->exec_sid;
2132 /* Reset exec SID on execve. */
2133 new_tsec->exec_sid = 0;
2134 } else {
2135 /* Check for a default transition on this program. */
2136 rc = security_transition_sid(old_tsec->sid, isec->sid,
2137 SECCLASS_PROCESS, &new_tsec->sid);
2138 if (rc)
2139 return rc;
2140 }
2141
2142 AVC_AUDIT_DATA_INIT(&ad, FS);
2143 ad.u.fs.path = bprm->file->f_path;
2144
2145 if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)
2146 new_tsec->sid = old_tsec->sid;
2147
2148 if (new_tsec->sid == old_tsec->sid) {
2149 rc = avc_has_perm(old_tsec->sid, isec->sid,
2150 SECCLASS_FILE, FILE__EXECUTE_NO_TRANS, &ad);
2151 if (rc)
2152 return rc;
2153 } else {
2154 /* Check permissions for the transition. */
2155 rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
2156 SECCLASS_PROCESS, PROCESS__TRANSITION, &ad);
2157 if (rc)
2158 return rc;
2159
2160 rc = avc_has_perm(new_tsec->sid, isec->sid,
2161 SECCLASS_FILE, FILE__ENTRYPOINT, &ad);
2162 if (rc)
2163 return rc;
2164
2165 /* Check for shared state */
2166 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
2167 rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
2168 SECCLASS_PROCESS, PROCESS__SHARE,
2169 NULL);
2170 if (rc)
2171 return -EPERM;
2172 }
2173
2174 /* Make sure that anyone attempting to ptrace over a task that
2175 * changes its SID has the appropriate permit */
2176 if (bprm->unsafe &
2177 (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
2178 struct task_struct *tracer;
2179 struct task_security_struct *sec;
2180 u32 ptsid = 0;
2181
2182 rcu_read_lock();
2183 tracer = tracehook_tracer_task(current);
2184 if (likely(tracer != NULL)) {
2185 sec = __task_cred(tracer)->security;
2186 ptsid = sec->sid;
2187 }
2188 rcu_read_unlock();
2189
2190 if (ptsid != 0) {
2191 rc = avc_has_perm(ptsid, new_tsec->sid,
2192 SECCLASS_PROCESS,
2193 PROCESS__PTRACE, NULL);
2194 if (rc)
2195 return -EPERM;
2196 }
2197 }
2198
2199 /* Clear any possibly unsafe personality bits on exec: */
2200 bprm->per_clear |= PER_CLEAR_ON_SETID;
2201 }
2202
2203 return 0;
2204 }
2205
2206 static int selinux_bprm_secureexec(struct linux_binprm *bprm)
2207 {
2208 const struct cred *cred = current_cred();
2209 const struct task_security_struct *tsec = cred->security;
2210 u32 sid, osid;
2211 int atsecure = 0;
2212
2213 sid = tsec->sid;
2214 osid = tsec->osid;
2215
2216 if (osid != sid) {
2217 /* Enable secure mode for SIDs transitions unless
2218 the noatsecure permission is granted between
2219 the two SIDs, i.e. ahp returns 0. */
2220 atsecure = avc_has_perm(osid, sid,
2221 SECCLASS_PROCESS,
2222 PROCESS__NOATSECURE, NULL);
2223 }
2224
2225 return (atsecure || cap_bprm_secureexec(bprm));
2226 }
2227
2228 extern struct vfsmount *selinuxfs_mount;
2229 extern struct dentry *selinux_null;
2230
2231 /* Derived from fs/exec.c:flush_old_files. */
2232 static inline void flush_unauthorized_files(const struct cred *cred,
2233 struct files_struct *files)
2234 {
2235 struct avc_audit_data ad;
2236 struct file *file, *devnull = NULL;
2237 struct tty_struct *tty;
2238 struct fdtable *fdt;
2239 long j = -1;
2240 int drop_tty = 0;
2241
2242 tty = get_current_tty();
2243 if (tty) {
2244 file_list_lock();
2245 if (!list_empty(&tty->tty_files)) {
2246 struct inode *inode;
2247
2248 /* Revalidate access to controlling tty.
2249 Use inode_has_perm on the tty inode directly rather
2250 than using file_has_perm, as this particular open
2251 file may belong to another process and we are only
2252 interested in the inode-based check here. */
2253 file = list_first_entry(&tty->tty_files, struct file, f_u.fu_list);
2254 inode = file->f_path.dentry->d_inode;
2255 if (inode_has_perm(cred, inode,
2256 FILE__READ | FILE__WRITE, NULL)) {
2257 drop_tty = 1;
2258 }
2259 }
2260 file_list_unlock();
2261 tty_kref_put(tty);
2262 }
2263 /* Reset controlling tty. */
2264 if (drop_tty)
2265 no_tty();
2266
2267 /* Revalidate access to inherited open files. */
2268
2269 AVC_AUDIT_DATA_INIT(&ad, FS);
2270
2271 spin_lock(&files->file_lock);
2272 for (;;) {
2273 unsigned long set, i;
2274 int fd;
2275
2276 j++;
2277 i = j * __NFDBITS;
2278 fdt = files_fdtable(files);
2279 if (i >= fdt->max_fds)
2280 break;
2281 set = fdt->open_fds->fds_bits[j];
2282 if (!set)
2283 continue;
2284 spin_unlock(&files->file_lock);
2285 for ( ; set ; i++, set >>= 1) {
2286 if (set & 1) {
2287 file = fget(i);
2288 if (!file)
2289 continue;
2290 if (file_has_perm(cred,
2291 file,
2292 file_to_av(file))) {
2293 sys_close(i);
2294 fd = get_unused_fd();
2295 if (fd != i) {
2296 if (fd >= 0)
2297 put_unused_fd(fd);
2298 fput(file);
2299 continue;
2300 }
2301 if (devnull) {
2302 get_file(devnull);
2303 } else {
2304 devnull = dentry_open(
2305 dget(selinux_null),
2306 mntget(selinuxfs_mount),
2307 O_RDWR, cred);
2308 if (IS_ERR(devnull)) {
2309 devnull = NULL;
2310 put_unused_fd(fd);
2311 fput(file);
2312 continue;
2313 }
2314 }
2315 fd_install(fd, devnull);
2316 }
2317 fput(file);
2318 }
2319 }
2320 spin_lock(&files->file_lock);
2321
2322 }
2323 spin_unlock(&files->file_lock);
2324 }
2325
2326 /*
2327 * Prepare a process for imminent new credential changes due to exec
2328 */
2329 static void selinux_bprm_committing_creds(struct linux_binprm *bprm)
2330 {
2331 struct task_security_struct *new_tsec;
2332 struct rlimit *rlim, *initrlim;
2333 int rc, i;
2334
2335 new_tsec = bprm->cred->security;
2336 if (new_tsec->sid == new_tsec->osid)
2337 return;
2338
2339 /* Close files for which the new task SID is not authorized. */
2340 flush_unauthorized_files(bprm->cred, current->files);
2341
2342 /* Always clear parent death signal on SID transitions. */
2343 current->pdeath_signal = 0;
2344
2345 /* Check whether the new SID can inherit resource limits from the old
2346 * SID. If not, reset all soft limits to the lower of the current
2347 * task's hard limit and the init task's soft limit.
2348 *
2349 * Note that the setting of hard limits (even to lower them) can be
2350 * controlled by the setrlimit check. The inclusion of the init task's
2351 * soft limit into the computation is to avoid resetting soft limits
2352 * higher than the default soft limit for cases where the default is
2353 * lower than the hard limit, e.g. RLIMIT_CORE or RLIMIT_STACK.
2354 */
2355 rc = avc_has_perm(new_tsec->osid, new_tsec->sid, SECCLASS_PROCESS,
2356 PROCESS__RLIMITINH, NULL);
2357 if (rc) {
2358 for (i = 0; i < RLIM_NLIMITS; i++) {
2359 rlim = current->signal->rlim + i;
2360 initrlim = init_task.signal->rlim + i;
2361 rlim->rlim_cur = min(rlim->rlim_max, initrlim->rlim_cur);
2362 }
2363 update_rlimit_cpu(current->signal->rlim[RLIMIT_CPU].rlim_cur);
2364 }
2365 }
2366
2367 /*
2368 * Clean up the process immediately after the installation of new credentials
2369 * due to exec
2370 */
2371 static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
2372 {
2373 const struct task_security_struct *tsec = current_security();
2374 struct itimerval itimer;
2375 u32 osid, sid;
2376 int rc, i;
2377
2378 osid = tsec->osid;
2379 sid = tsec->sid;
2380
2381 if (sid == osid)
2382 return;
2383
2384 /* Check whether the new SID can inherit signal state from the old SID.
2385 * If not, clear itimers to avoid subsequent signal generation and
2386 * flush and unblock signals.
2387 *
2388 * This must occur _after_ the task SID has been updated so that any
2389 * kill done after the flush will be checked against the new SID.
2390 */
2391 rc = avc_has_perm(osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL);
2392 if (rc) {
2393 memset(&itimer, 0, sizeof itimer);
2394 for (i = 0; i < 3; i++)
2395 do_setitimer(i, &itimer, NULL);
2396 spin_lock_irq(¤t->sighand->siglock);
2397 if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
2398 __flush_signals(current);
2399 flush_signal_handlers(current, 1);
2400 sigemptyset(¤t->blocked);
2401 }
2402 spin_unlock_irq(¤t->sighand->siglock);
2403 }
2404
2405 /* Wake up the parent if it is waiting so that it can recheck
2406 * wait permission to the new task SID. */
2407 read_lock(&tasklist_lock);
2408 wake_up_interruptible(¤t->real_parent->signal->wait_chldexit);
2409 read_unlock(&tasklist_lock);
2410 }
2411
2412 /* superblock security operations */
2413
2414 static int selinux_sb_alloc_security(struct super_block *sb)
2415 {
2416 return superblock_alloc_security(sb);
2417 }
2418
2419 static void selinux_sb_free_security(struct super_block *sb)
2420 {
2421 superblock_free_security(sb);
2422 }
2423
2424 static inline int match_prefix(char *prefix, int plen, char *option, int olen)
2425 {
2426 if (plen > olen)
2427 return 0;
2428
2429 return !memcmp(prefix, option, plen);
2430 }
2431
2432 static inline int selinux_option(char *option, int len)
2433 {
2434 return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
2435 match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
2436 match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
2437 match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len) ||
2438 match_prefix(LABELSUPP_STR, sizeof(LABELSUPP_STR)-1, option, len));
2439 }
2440
2441 static inline void take_option(char **to, char *from, int *first, int len)
2442 {
2443 if (!*first) {
2444 **to = ',';
2445 *to += 1;
2446 } else
2447 *first = 0;
2448 memcpy(*to, from, len);
2449 *to += len;
2450 }
2451
2452 static inline void take_selinux_option(char **to, char *from, int *first,
2453 int len)
2454 {
2455 int current_size = 0;
2456
2457 if (!*first) {
2458 **to = '|';
2459 *to += 1;
2460 } else
2461 *first = 0;
2462
2463 while (current_size < len) {
2464 if (*from != '"') {
2465 **to = *from;
2466 *to += 1;
2467 }
2468 from += 1;
2469 current_size += 1;
2470 }
2471 }
2472
2473 static int selinux_sb_copy_data(char *orig, char *copy)
2474 {
2475 int fnosec, fsec, rc = 0;
2476 char *in_save, *in_curr, *in_end;
2477 char *sec_curr, *nosec_save, *nosec;
2478 int open_quote = 0;
2479
2480 in_curr = orig;
2481 sec_curr = copy;
2482
2483 nosec = (char *)get_zeroed_page(GFP_KERNEL);
2484 if (!nosec) {
2485 rc = -ENOMEM;
2486 goto out;
2487 }
2488
2489 nosec_save = nosec;
2490 fnosec = fsec = 1;
2491 in_save = in_end = orig;
2492
2493 do {
2494 if (*in_end == '"')
2495 open_quote = !open_quote;
2496 if ((*in_end == ',' && open_quote == 0) ||
2497 *in_end == '\0') {
2498 int len = in_end - in_curr;
2499
2500 if (selinux_option(in_curr, len))
2501 take_selinux_option(&sec_curr, in_curr, &fsec, len);
2502 else
2503 take_option(&nosec, in_curr, &fnosec, len);
2504
2505 in_curr = in_end + 1;
2506 }
2507 } while (*in_end++);
2508
2509 strcpy(in_save, nosec_save);
2510 free_page((unsigned long)nosec_save);
2511 out:
2512 return rc;
2513 }
2514
2515 static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
2516 {
2517 const struct cred *cred = current_cred();
2518 struct avc_audit_data ad;
2519 int rc;
2520
2521 rc = superblock_doinit(sb, data);
2522 if (rc)
2523 return rc;
2524
2525 /* Allow all mounts performed by the kernel */
2526 if (flags & MS_KERNMOUNT)
2527 return 0;
2528
2529 AVC_AUDIT_DATA_INIT(&ad, FS);
2530 ad.u.fs.path.dentry = sb->s_root;
2531 return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad);
2532 }
2533
2534 static int selinux_sb_statfs(struct dentry *dentry)
2535 {
2536 const struct cred *cred = current_cred();
2537 struct avc_audit_data ad;
2538
2539 AVC_AUDIT_DATA_INIT(&ad, FS);
2540 ad.u.fs.path.dentry = dentry->d_sb->s_root;
2541 return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad);
2542 }
2543
2544 static int selinux_mount(char *dev_name,
2545 struct path *path,
2546 char *type,
2547 unsigned long flags,
2548 void *data)
2549 {
2550 const struct cred *cred = current_cred();
2551
2552 if (flags & MS_REMOUNT)
2553 return superblock_has_perm(cred, path->mnt->mnt_sb,
2554 FILESYSTEM__REMOUNT, NULL);
2555 else
2556 return dentry_has_perm(cred, path->mnt, path->dentry,
2557 FILE__MOUNTON);
2558 }
2559
2560 static int selinux_umount(struct vfsmount *mnt, int flags)
2561 {
2562 const struct cred *cred = current_cred();
2563
2564 return superblock_has_perm(cred, mnt->mnt_sb,
2565 FILESYSTEM__UNMOUNT, NULL);
2566 }
2567
2568 /* inode security operations */
2569
2570 static int selinux_inode_alloc_security(struct inode *inode)
2571 {
2572 return inode_alloc_security(inode);
2573 }
2574
2575 static void selinux_inode_free_security(struct inode *inode)
2576 {
2577 inode_free_security(inode);
2578 }
2579
2580 static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
2581 char **name, void **value,
2582 size_t *len)
2583 {
2584 const struct cred *cred = current_cred();
2585 const struct task_security_struct *tsec = cred->security;
2586 struct inode_security_struct *dsec;
2587 struct superblock_security_struct *sbsec;
2588 u32 sid, newsid, clen;
2589 int rc;
2590 char *namep = NULL, *context;
2591
2592 dsec = dir->i_security;
2593 sbsec = dir->i_sb->s_security;
2594
2595 sid = tsec->sid;
2596 newsid = tsec->create_sid;
2597
2598 if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) {
2599 rc = security_transition_sid(sid, dsec->sid,
2600 inode_mode_to_security_class(inode->i_mode),
2601 &newsid);
2602 if (rc) {
2603 printk(KERN_WARNING "%s: "
2604 "security_transition_sid failed, rc=%d (dev=%s "
2605 "ino=%ld)\n",
2606 __func__,
2607 -rc, inode->i_sb->s_id, inode->i_ino);
2608 return rc;
2609 }
2610 }
2611
2612 /* Possibly defer initialization to selinux_complete_init. */
2613 if (sbsec->flags & SE_SBINITIALIZED) {
2614 struct inode_security_struct *isec = inode->i_security;
2615 isec->sclass = inode_mode_to_security_class(inode->i_mode);
2616 isec->sid = newsid;
2617 isec->initialized = 1;
2618 }
2619
2620 if (!ss_initialized || !(sbsec->flags & SE_SBLABELSUPP))
2621 return -EOPNOTSUPP;
2622
2623 if (name) {
2624 namep = kstrdup(XATTR_SELINUX_SUFFIX, GFP_NOFS);
2625 if (!namep)
2626 return -ENOMEM;
2627 *name = namep;
2628 }
2629
2630 if (value && len) {
2631 rc = security_sid_to_context_force(newsid, &context, &clen);
2632 if (rc) {
2633 kfree(namep);
2634 return rc;
2635 }
2636 *value = context;
2637 *len = clen;
2638 }
2639
2640 return 0;
2641 }
2642
2643 static int selinux_inode_create(struct inode *dir, struct dentry *dentry, int mask)
2644 {
2645 return may_create(dir, dentry, SECCLASS_FILE);
2646 }
2647
2648 static int selinux_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
2649 {
2650 return may_link(dir, old_dentry, MAY_LINK);
2651 }
2652
2653 static int selinux_inode_unlink(struct inode *dir, struct dentry *dentry)
2654 {
2655 return may_link(dir, dentry, MAY_UNLINK);
2656 }
2657
2658 static int selinux_inode_symlink(struct inode *dir, struct dentry *dentry, const char *name)
2659 {
2660 return may_create(dir, dentry, SECCLASS_LNK_FILE);
2661 }
2662
2663 static int selinux_inode_mkdir(struct inode *dir, struct dentry *dentry, int mask)
2664 {
2665 return may_create(dir, dentry, SECCLASS_DIR);
2666 }
2667
2668 static int selinux_inode_rmdir(struct inode *dir, struct dentry *dentry)
2669 {
2670 return may_link(dir, dentry, MAY_RMDIR);
2671 }
2672
2673 static int selinux_inode_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
2674 {
2675 return may_create(dir, dentry, inode_mode_to_security_class(mode));
2676 }
2677
2678 static int selinux_inode_rename(struct inode *old_inode, struct dentry *old_dentry,
2679 struct inode *new_inode, struct dentry *new_dentry)
2680 {
2681 return may_rename(old_inode, old_dentry, new_inode, new_dentry);
2682 }
2683
2684 static int selinux_inode_readlink(struct dentry *dentry)
2685 {
2686 const struct cred *cred = current_cred();
2687
2688 return dentry_has_perm(cred, NULL, dentry, FILE__READ);
2689 }
2690
2691 static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *nameidata)
2692 {
2693 const struct cred *cred = current_cred();
2694
2695 return dentry_has_perm(cred, NULL, dentry, FILE__READ);
2696 }
2697
2698 static int selinux_inode_permission(struct inode *inode, int mask)
2699 {
2700 const struct cred *cred = current_cred();
2701
2702 if (!mask) {
2703 /* No permission to check. Existence test. */
2704 return 0;
2705 }
2706
2707 return inode_has_perm(cred, inode,
2708 file_mask_to_av(inode->i_mode, mask), NULL);
2709 }
2710
2711 static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
2712 {
2713 const struct cred *cred = current_cred();
2714
2715 if (iattr->ia_valid & ATTR_FORCE)
2716 return 0;
2717
2718 if (iattr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID |
2719 ATTR_ATIME_SET | ATTR_MTIME_SET))
2720 return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR);
2721
2722 return dentry_has_perm(cred, NULL, dentry, FILE__WRITE);
2723 }
2724
2725 static int selinux_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
2726 {
2727 const struct cred *cred = current_cred();
2728
2729 return dentry_has_perm(cred, mnt, dentry, FILE__GETATTR);
2730 }
2731
2732 static int selinux_inode_setotherxattr(struct dentry *dentry, const char *name)
2733 {
2734 const struct cred *cred = current_cred();
2735
2736 if (!strncmp(name, XATTR_SECURITY_PREFIX,
2737 sizeof XATTR_SECURITY_PREFIX - 1)) {
2738 if (!strcmp(name, XATTR_NAME_CAPS)) {
2739 if (!capable(CAP_SETFCAP))
2740 return -EPERM;
2741 } else if (!capable(CAP_SYS_ADMIN)) {
2742 /* A different attribute in the security namespace.
2743 Restrict to administrator. */
2744 return -EPERM;
2745 }
2746 }
2747
2748 /* Not an attribute we recognize, so just check the
2749 ordinary setattr permission. */
2750 return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR);
2751 }
2752
2753 static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
2754 const void *value, size_t size, int flags)
2755 {
2756 struct inode *inode = dentry->d_inode;
2757 struct inode_security_struct *isec = inode->i_security;
2758 struct superblock_security_struct *sbsec;
2759 struct avc_audit_data ad;
2760 u32 newsid, sid = current_sid();
2761 int rc = 0;
2762
2763 if (strcmp(name, XATTR_NAME_SELINUX))
2764 return selinux_inode_setotherxattr(dentry, name);
2765
2766 sbsec = inode->i_sb->s_security;
2767 if (!(sbsec->flags & SE_SBLABELSUPP))
2768 return -EOPNOTSUPP;
2769
2770 if (!is_owner_or_cap(inode))
2771 return -EPERM;
2772
2773 AVC_AUDIT_DATA_INIT(&ad, FS);
2774 ad.u.fs.path.dentry = dentry;
2775
2776 rc = avc_has_perm(sid, isec->sid, isec->sclass,
2777 FILE__RELABELFROM, &ad);
2778 if (rc)
2779 return rc;
2780
2781 rc = security_context_to_sid(value, size, &newsid);
2782 if (rc == -EINVAL) {
2783 if (!capable(CAP_MAC_ADMIN))
2784 return rc;
2785 rc = security_context_to_sid_force(value, size, &newsid);
2786 }
2787 if (rc)
2788 return rc;
2789
2790 rc = avc_has_perm(sid, newsid, isec->sclass,
2791 FILE__RELABELTO, &ad);
2792 if (rc)
2793 return rc;
2794
2795 rc = security_validate_transition(isec->sid, newsid, sid,
2796 isec->sclass);
2797 if (rc)
2798 return rc;
2799
2800 return avc_has_perm(newsid,
2801 sbsec->sid,
2802 SECCLASS_FILESYSTEM,
2803 FILESYSTEM__ASSOCIATE,
2804 &ad);
2805 }
2806
2807 static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name,
2808 const void *value, size_t size,
2809 int flags)
2810 {
2811 struct inode *inode = dentry->d_inode;
2812 struct inode_security_struct *isec = inode->i_security;
2813 u32 newsid;
2814 int rc;
2815
2816 if (strcmp(name, XATTR_NAME_SELINUX)) {
2817 /* Not an attribute we recognize, so nothing to do. */
2818 return;
2819 }
2820
2821 rc = security_context_to_sid_force(value, size, &newsid);
2822 if (rc) {
2823 printk(KERN_ERR "SELinux: unable to map context to SID"
2824 "for (%s, %lu), rc=%d\n",
2825 inode->i_sb->s_id, inode->i_ino, -rc);
2826 return;
2827 }
2828
2829 isec->sid = newsid;
2830 return;
2831 }
2832
2833 static int selinux_inode_getxattr(struct dentry *dentry, const char *name)
2834 {
2835 const struct cred *cred = current_cred();
2836
2837 return dentry_has_perm(cred, NULL, dentry, FILE__GETATTR);
2838 }
2839
2840 static int selinux_inode_listxattr(struct dentry *dentry)
2841 {
2842 const struct cred *cred = current_cred();
2843
2844 return dentry_has_perm(cred, NULL, dentry, FILE__GETATTR);
2845 }
2846
2847 static int selinux_inode_removexattr(struct dentry *dentry, const char *name)
2848 {
2849 if (strcmp(name, XATTR_NAME_SELINUX))
2850 return selinux_inode_setotherxattr(dentry, name);
2851
2852 /* No one is allowed to remove a SELinux security label.
2853 You can change the label, but all data must be labeled. */
2854 return -EACCES;
2855 }
2856
2857 /*
2858 * Copy the inode security context value to the user.
2859 *
2860 * Permission check is handled by selinux_inode_getxattr hook.
2861 */
2862 static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc)
2863 {
2864 u32 size;
2865 int error;
2866 char *context = NULL;
2867 struct inode_security_struct *isec = inode->i_security;
2868
2869 if (strcmp(name, XATTR_SELINUX_SUFFIX))
2870 return -EOPNOTSUPP;
2871
2872 /*
2873 * If the caller has CAP_MAC_ADMIN, then get the raw context
2874 * value even if it is not defined by current policy; otherwise,
2875 * use the in-core value under current policy.
2876 * Use the non-auditing forms of the permission checks since
2877 * getxattr may be called by unprivileged processes commonly
2878 * and lack of permission just means that we fall back to the
2879 * in-core context value, not a denial.
2880 */
2881 error = selinux_capable(current, current_cred(), CAP_MAC_ADMIN,
2882 SECURITY_CAP_NOAUDIT);
2883 if (!error)
2884 error = security_sid_to_context_force(isec->sid, &context,
2885 &size);
2886 else
2887 error = security_sid_to_context(isec->sid, &context, &size);
2888 if (error)
2889 return error;
2890 error = size;
2891 if (alloc) {
2892 *buffer = context;
2893 goto out_nofree;
2894 }
2895 kfree(context);
2896 out_nofree:
2897 return error;
2898 }
2899
2900 static int selinux_inode_setsecurity(struct inode *inode, const char *name,
2901 const void *value, size_t size, int flags)
2902 {
2903 struct inode_security_struct *isec = inode->i_security;
2904 u32 newsid;
2905 int rc;
2906
2907 if (strcmp(name, XATTR_SELINUX_SUFFIX))
2908 return -EOPNOTSUPP;
2909
2910 if (!value || !size)
2911 return -EACCES;
2912
2913 rc = security_context_to_sid((void *)value, size, &newsid);
2914 if (rc)
2915 return rc;
2916
2917 isec->sid = newsid;
2918 return 0;
2919 }
2920
2921 static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)
2922 {
2923 const int len = sizeof(XATTR_NAME_SELINUX);
2924 if (buffer && len <= buffer_size)
2925 memcpy(buffer, XATTR_NAME_SELINUX, len);
2926 return len;
2927 }
2928
2929 static void selinux_inode_getsecid(const struct inode *inode, u32 *secid)
2930 {
2931 struct inode_security_struct *isec = inode->i_security;
2932 *secid = isec->sid;
2933 }
2934
2935 /* file security operations */
2936
2937 static int selinux_revalidate_file_permission(struct file *file, int mask)
2938 {
2939 const struct cred *cred = current_cred();
2940 struct inode *inode = file->f_path.dentry->d_inode;
2941
2942 if (!mask) {
2943 /* No permission to check. Existence test. */
2944 return 0;
2945 }
2946
2947 /* file_mask_to_av won't add FILE__WRITE if MAY_APPEND is set */
2948 if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE))
2949 mask |= MAY_APPEND;
2950
2951 return file_has_perm(cred, file,
2952 file_mask_to_av(inode->i_mode, mask));
2953 }
2954
2955 static int selinux_file_permission(struct file *file, int mask)
2956 {
2957 if (!mask)
2958 /* No permission to check. Existence test. */
2959 return 0;
2960
2961 return selinux_revalidate_file_permission(file, mask);
2962 }
2963
2964 static int selinux_file_alloc_security(struct file *file)
2965 {
2966 return file_alloc_security(file);
2967 }
2968
2969 static void selinux_file_free_security(struct file *file)
2970 {
2971 file_free_security(file);
2972 }
2973
2974 static int selinux_file_ioctl(struct file *file, unsigned int cmd,
2975 unsigned long arg)
2976 {
2977 const struct cred *cred = current_cred();
2978 u32 av = 0;
2979
2980 if (_IOC_DIR(cmd) & _IOC_WRITE)
2981 av |= FILE__WRITE;
2982 if (_IOC_DIR(cmd) & _IOC_READ)
2983 av |= FILE__READ;
2984 if (!av)
2985 av = FILE__IOCTL;
2986
2987 return file_has_perm(cred, file, av);
2988 }
2989
2990 static int file_map_prot_check(struct file *file, unsigned long prot, int shared)
2991 {
2992 const struct cred *cred = current_cred();
2993 int rc = 0;
2994
2995 #ifndef CONFIG_PPC32
2996 if ((prot & PROT_EXEC) && (!file || (!shared && (prot & PROT_WRITE)))) {
2997 /*
2998 * We are making executable an anonymous mapping or a
2999 * private file mapping that will also be writable.
3000 * This has an additional check.
3001 */
3002 rc = cred_has_perm(cred, cred, PROCESS__EXECMEM);
3003 if (rc)
3004 goto error;
3005 }
3006 #endif
3007
3008 if (file) {
3009 /* read access is always possible with a mapping */
3010 u32 av = FILE__READ;
3011
3012 /* write access only matters if the mapping is shared */
3013 if (shared && (prot & PROT_WRITE))
3014 av |= FILE__WRITE;
3015
3016 if (prot & PROT_EXEC)
3017 av |= FILE__EXECUTE;
3018
3019 return file_has_perm(cred, file, av);
3020 }
3021
3022 error:
3023 return rc;
3024 }
3025
3026 static int selinux_file_mmap(struct file *file, unsigned long reqprot,
3027 unsigned long prot, unsigned long flags,
3028 unsigned long addr, unsigned long addr_only)
3029 {
3030 int rc = 0;
3031 u32 sid = current_sid();
3032
3033 /*
3034 * notice that we are intentionally putting the SELinux check before
3035 * the secondary cap_file_mmap check. This is such a likely attempt
3036 * at bad behaviour/exploit that we always want to get the AVC, even
3037 * if DAC would have also denied the operation.
3038 */
3039 if (addr < CONFIG_LSM_MMAP_MIN_ADDR) {
3040 rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
3041 MEMPROTECT__MMAP_ZERO, NULL);
3042 if (rc)
3043 return rc;
3044 }
3045
3046 /* do DAC check on address space usage */
3047 rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
3048 if (rc || addr_only)
3049 return rc;
3050
3051 if (selinux_checkreqprot)
3052 prot = reqprot;
3053
3054 return file_map_prot_check(file, prot,
3055 (flags & MAP_TYPE) == MAP_SHARED);
3056 }
3057
3058 static int selinux_file_mprotect(struct vm_area_struct *vma,
3059 unsigned long reqprot,
3060 unsigned long prot)
3061 {
3062 const struct cred *cred = current_cred();
3063
3064 if (selinux_checkreqprot)
3065 prot = reqprot;
3066
3067 #ifndef CONFIG_PPC32
3068 if ((prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
3069 int rc = 0;
3070 if (vma->vm_start >= vma->vm_mm->start_brk &&
3071 vma->vm_end <= vma->vm_mm->brk) {
3072 rc = cred_has_perm(cred, cred, PROCESS__EXECHEAP);
3073 } else if (!vma->vm_file &&
3074 vma->vm_start <= vma->vm_mm->start_stack &&
3075 vma->vm_end >= vma->vm_mm->start_stack) {
3076 rc = current_has_perm(current, PROCESS__EXECSTACK);
3077 } else if (vma->vm_file && vma->anon_vma) {
3078 /*
3079 * We are making executable a file mapping that has
3080 * had some COW done. Since pages might have been
3081 * written, check ability to execute the possibly
3082 * modified content. This typically should only
3083 * occur for text relocations.
3084 */
3085 rc = file_has_perm(cred, vma->vm_file, FILE__EXECMOD);
3086 }
3087 if (rc)
3088 return rc;
3089 }
3090 #endif
3091
3092 return file_map_prot_check(vma->vm_file, prot, vma->vm_flags&VM_SHARED);
3093 }
3094
3095 static int selinux_file_lock(struct file *file, unsigned int cmd)
3096 {
3097 const struct cred *cred = current_cred();
3098
3099 return file_has_perm(cred, file, FILE__LOCK);
3100 }
3101
3102 static int selinux_file_fcntl(struct file *file, unsigned int cmd,
3103 unsigned long arg)
3104 {
3105 const struct cred *cred = current_cred();
3106 int err = 0;
3107
3108 switch (cmd) {
3109 case F_SETFL:
3110 if (!file->f_path.dentry || !file->f_path.dentry->d_inode) {
3111 err = -EINVAL;
3112 break;
3113 }
3114
3115 if ((file->f_flags & O_APPEND) && !(arg & O_APPEND)) {
3116 err = file_has_perm(cred, file, FILE__WRITE);
3117 break;
3118 }
3119 /* fall through */
3120 case F_SETOWN:
3121 case F_SETSIG:
3122 case F_GETFL:
3123 case F_GETOWN:
3124 case F_GETSIG:
3125 /* Just check FD__USE permission */
3126 err = file_has_perm(cred, file, 0);
3127 break;
3128 case F_GETLK:
3129 case F_SETLK:
3130 case F_SETLKW:
3131 #if BITS_PER_LONG == 32
3132 case F_GETLK64:
3133 case F_SETLK64:
3134 case F_SETLKW64:
3135 #endif
3136 if (!file->f_path.dentry || !file->f_path.dentry->d_inode) {
3137 err = -EINVAL;
3138 break;
3139 }
3140 err = file_has_perm(cred, file, FILE__LOCK);
3141 break;
3142 }
3143
3144 return err;
3145 }
3146
3147 static int selinux_file_set_fowner(struct file *file)
3148 {
3149 struct file_security_struct *fsec;
3150
3151 fsec = file->f_security;
3152 fsec->fown_sid = current_sid();
3153
3154 return 0;
3155 }
3156
3157 static int selinux_file_send_sigiotask(struct task_struct *tsk,
3158 struct fown_struct *fown, int signum)
3159 {
3160 struct file *file;
3161 u32 sid = task_sid(tsk);
3162 u32 perm;
3163 struct file_security_struct *fsec;
3164
3165 /* struct fown_struct is never outside the context of a struct file */
3166 file = container_of(fown, struct file, f_owner);
3167
3168 fsec = file->f_security;
3169
3170 if (!signum)
3171 perm = signal_to_av(SIGIO); /* as per send_sigio_to_task */
3172 else
3173 perm = signal_to_av(signum);
3174
3175 return avc_has_perm(fsec->fown_sid, sid,
3176 SECCLASS_PROCESS, perm, NULL);
3177 }
3178
3179 static int selinux_file_receive(struct file *file)
3180 {
3181 const struct cred *cred = current_cred();
3182
3183 return file_has_perm(cred, file, file_to_av(file));
3184 }
3185
3186 static int selinux_dentry_open(struct file *file, const struct cred *cred)
3187 {
3188 struct file_security_struct *fsec;
3189 struct inode *inode;
3190 struct inode_security_struct *isec;
3191
3192 inode = file->f_path.dentry->d_inode;
3193 fsec = file->f_security;
3194 isec = inode->i_security;
3195 /*
3196 * Save inode label and policy sequence number
3197 * at open-time so that selinux_file_permission
3198 * can determine whether revalidation is necessary.
3199 * Task label is already saved in the file security
3200 * struct as its SID.
3201 */
3202 fsec->isid = isec->sid;
3203 fsec->pseqno = avc_policy_seqno();
3204 /*
3205 * Since the inode label or policy seqno may have changed
3206 * between the selinux_inode_permission check and the saving
3207 * of state above, recheck that access is still permitted.
3208 * Otherwise, access might never be revalidated against the
3209 * new inode label or new policy.
3210 * This check is not redundant - do not remove.
3211 */
3212 return inode_has_perm(cred, inode, open_file_to_av(file), NULL);
3213 }
3214
3215 /* task security operations */
3216
3217 static int selinux_task_create(unsigned long clone_flags)
3218 {
3219 return current_has_perm(current, PROCESS__FORK);
3220 }
3221
3222 /*
3223 * detach and free the LSM part of a set of credentials
3224 */
3225 static void selinux_cred_free(struct cred *cred)
3226 {
3227 struct task_security_struct *tsec = cred->security;
3228 cred->security = NULL;
3229 kfree(tsec);
3230 }
3231
3232 /*
3233 * prepare a new set of credentials for modification
3234 */
3235 static int selinux_cred_prepare(struct cred *new, const struct cred *old,
3236 gfp_t gfp)
3237 {
3238 const struct task_security_struct *old_tsec;
3239 struct task_security_struct *tsec;
3240
3241 old_tsec = old->security;
3242
3243 tsec = kmemdup(old_tsec, sizeof(struct task_security_struct), gfp);
3244 if (!tsec)
3245 return -ENOMEM;
3246
3247 new->security = tsec;
3248 return 0;
3249 }
3250
3251 /*
3252 * set the security data for a kernel service
3253 * - all the creation contexts are set to unlabelled
3254 */
3255 static int selinux_kernel_act_as(struct cred *new, u32 secid)
3256 {
3257 struct task_security_struct *tsec = new->security;
3258 u32 sid = current_sid();
3259 int ret;
3260
3261 ret = avc_has_perm(sid, secid,
3262 SECCLASS_KERNEL_SERVICE,
3263 KERNEL_SERVICE__USE_AS_OVERRIDE,
3264 NULL);
3265 if (ret == 0) {
3266 tsec->sid = secid;
3267 tsec->create_sid = 0;
3268 tsec->keycreate_sid = 0;
3269 tsec->sockcreate_sid = 0;
3270 }
3271 return ret;
3272 }
3273
3274 /*
3275 * set the file creation context in a security record to the same as the
3276 * objective context of the specified inode
3277 */
3278 static int selinux_kernel_create_files_as(struct cred *new, struct inode *inode)
3279 {
3280 struct inode_security_struct *isec = inode->i_security;
3281 struct task_security_struct *tsec = new->security;
3282 u32 sid = current_sid();
3283 int ret;
3284
3285 ret = avc_has_perm(sid, isec->sid,
3286 SECCLASS_KERNEL_SERVICE,
3287 KERNEL_SERVICE__CREATE_FILES_AS,
3288 NULL);
3289
3290 if (ret == 0)
3291 tsec->create_sid = isec->sid;
3292 return 0;
3293 }
3294
3295 static int selinux_task_setpgid(struct task_struct *p, pid_t pgid)
3296 {
3297 return current_has_perm(p, PROCESS__SETPGID);
3298 }
3299
3300 static int selinux_task_getpgid(struct task_struct *p)
3301 {
3302 return current_has_perm(p, PROCESS__GETPGID);
3303 }
3304
3305 static int selinux_task_getsid(struct task_struct *p)
3306 {
3307 return current_has_perm(p, PROCESS__GETSESSION);
3308 }
3309
3310 static void selinux_task_getsecid(struct task_struct *p, u32 *secid)
3311 {
3312 *secid = task_sid(p);
3313 }
3314
3315 static int selinux_task_setnice(struct task_struct *p, int nice)
3316 {
3317 int rc;
3318
3319 rc = cap_task_setnice(p, nice);
3320 if (rc)
3321 return rc;
3322
3323 return current_has_perm(p, PROCESS__SETSCHED);
3324 }
3325
3326 static int selinux_task_setioprio(struct task_struct *p, int ioprio)
3327 {
3328 int rc;
3329
3330 rc = cap_task_setioprio(p, ioprio);
3331 if (rc)
3332 return rc;
3333
3334 return current_has_perm(p, PROCESS__SETSCHED);
3335 }
3336
3337 static int selinux_task_getioprio(struct task_struct *p)
3338 {
3339 return current_has_perm(p, PROCESS__GETSCHED);
3340 }
3341
3342 static int selinux_task_setrlimit(unsigned int resource, struct rlimit *new_rlim)
3343 {
3344 struct rlimit *old_rlim = current->signal->rlim + resource;
3345
3346 /* Control the ability to change the hard limit (whether
3347 lowering or raising it), so that the hard limit can
3348 later be used as a safe reset point for the soft limit
3349 upon context transitions. See selinux_bprm_committing_creds. */
3350 if (old_rlim->rlim_max != new_rlim->rlim_max)
3351 return current_has_perm(current, PROCESS__SETRLIMIT);
3352
3353 return 0;
3354 }
3355
3356 static int selinux_task_setscheduler(struct task_struct *p, int policy, struct sched_param *lp)
3357 {
3358 int rc;
3359
3360 rc = cap_task_setscheduler(p, policy, lp);
3361 if (rc)
3362 return rc;
3363
3364 return current_has_perm(p, PROCESS__SETSCHED);
3365 }
3366
3367 static int selinux_task_getscheduler(struct task_struct *p)
3368 {
3369 return current_has_perm(p, PROCESS__GETSCHED);
3370 }
3371
3372 static int selinux_task_movememory(struct task_struct *p)
3373 {
3374 return current_has_perm(p, PROCESS__SETSCHED);
3375 }
3376
3377 static int selinux_task_kill(struct task_struct *p, struct siginfo *info,
3378 int sig, u32 secid)
3379 {
3380 u32 perm;
3381 int rc;
3382
3383 if (!sig)
3384 perm = PROCESS__SIGNULL; /* null signal; existence test */
3385 else
3386 perm = signal_to_av(sig);
3387 if (secid)
3388 rc = avc_has_perm(secid, task_sid(p),
3389 SECCLASS_PROCESS, perm, NULL);
3390 else
3391 rc = current_has_perm(p, perm);
3392 return rc;
3393 }
3394
3395 static int selinux_task_wait(struct task_struct *p)
3396 {
3397 return task_has_perm(p, current, PROCESS__SIGCHLD);
3398 }
3399
3400 static void selinux_task_to_inode(struct task_struct *p,
3401 struct inode *inode)
3402 {
3403 struct inode_security_struct *isec = inode->i_security;
3404 u32 sid = task_sid(p);
3405
3406 isec->sid = sid;
3407 isec->initialized = 1;
3408 }
3409
3410 /* Returns error only if unable to parse addresses */
3411 static int selinux_parse_skb_ipv4(struct sk_buff *skb,
3412 struct avc_audit_data *ad, u8 *proto)
3413 {
3414 int offset, ihlen, ret = -EINVAL;
3415 struct iphdr _iph, *ih;
3416
3417 offset = skb_network_offset(skb);
3418 ih = skb_header_pointer(skb, offset, sizeof(_iph), &_iph);
3419 if (ih == NULL)
3420 goto out;
3421
3422 ihlen = ih->ihl * 4;
3423 if (ihlen < sizeof(_iph))
3424 goto out;
3425
3426 ad->u.net.v4info.saddr = ih->saddr;
3427 ad->u.net.v4info.daddr = ih->daddr;
3428 ret = 0;
3429
3430 if (proto)
3431 *proto = ih->protocol;
3432
3433 switch (ih->protocol) {
3434 case IPPROTO_TCP: {
3435 struct tcphdr _tcph, *th;
3436
3437 if (ntohs(ih->frag_off) & IP_OFFSET)
3438 break;
3439
3440 offset += ihlen;
3441 th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
3442 if (th == NULL)
3443 break;
3444
3445 ad->u.net.sport = th->source;
3446 ad->u.net.dport = th->dest;
3447 break;
3448 }
3449
3450 case IPPROTO_UDP: {
3451 struct udphdr _udph, *uh;
3452
3453 if (ntohs(ih->frag_off) & IP_OFFSET)
3454 break;
3455
3456 offset += ihlen;
3457 uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
3458 if (uh == NULL)
3459 break;
3460
3461 ad->u.net.sport = uh->source;
3462 ad->u.net.dport = uh->dest;
3463 break;
3464 }
3465
3466 case IPPROTO_DCCP: {
3467 struct dccp_hdr _dccph, *dh;
3468
3469 if (ntohs(ih->frag_off) & IP_OFFSET)
3470 break;
3471
3472 offset += ihlen;
3473 dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
3474 if (dh == NULL)
3475 break;
3476
3477 ad->u.net.sport = dh->dccph_sport;
3478 ad->u.net.dport = dh->dccph_dport;
3479 break;
3480 }
3481
3482 default:
3483 break;
3484 }
3485 out:
3486 return ret;
3487 }
3488
3489 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
3490
3491 /* Returns error only if unable to parse addresses */
3492 static int selinux_parse_skb_ipv6(struct sk_buff *skb,
3493 struct avc_audit_data *ad, u8 *proto)
3494 {
3495 u8 nexthdr;
3496 int ret = -EINVAL, offset;
3497 struct ipv6hdr _ipv6h, *ip6;
3498
3499 offset = skb_network_offset(skb);
3500 ip6 = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
3501 if (ip6 == NULL)
3502 goto out;
3503
3504 ipv6_addr_copy(&ad->u.net.v6info.saddr, &ip6->saddr);
3505 ipv6_addr_copy(&ad->u.net.v6info.daddr, &ip6->daddr);
3506 ret = 0;
3507
3508 nexthdr = ip6->nexthdr;
3509 offset += sizeof(_ipv6h);
3510 offset = ipv6_skip_exthdr(skb, offset, &nexthdr);
3511 if (offset < 0)
3512 goto out;
3513
3514 if (proto)
3515 *proto = nexthdr;
3516
3517 switch (nexthdr) {
3518 case IPPROTO_TCP: {
3519 struct tcphdr _tcph, *th;
3520
3521 th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
3522 if (th == NULL)
3523 break;
3524
3525 ad->u.net.sport = th->source;
3526 ad->u.net.dport = th->dest;
3527 break;
3528 }
3529
3530 case IPPROTO_UDP: {
3531 struct udphdr _udph, *uh;
3532
3533 uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
3534 if (uh == NULL)
3535 break;
3536
3537 ad->u.net.sport = uh->source;
3538 ad->u.net.dport = uh->dest;
3539 break;
3540 }
3541
3542 case IPPROTO_DCCP: {
3543 struct dccp_hdr _dccph, *dh;
3544
3545 dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph);
3546 if (dh == NULL)
3547 break;
3548
3549 ad->u.net.sport = dh->dccph_sport;
3550 ad->u.net.dport = dh->dccph_dport;
3551 break;
3552 }
3553
3554 /* includes fragments */
3555 default:
3556 break;
3557 }
3558 out:
3559 return ret;
3560 }
3561
3562 #endif /* IPV6 */
3563
3564 static int selinux_parse_skb(struct sk_buff *skb, struct avc_audit_data *ad,
3565 char **_addrp, int src, u8 *proto)
3566 {
3567 char *addrp;
3568 int ret;
3569
3570 switch (ad->u.net.family) {
3571 case PF_INET:
3572 ret = selinux_parse_skb_ipv4(skb, ad, proto);
3573 if (ret)
3574 goto parse_error;
3575 addrp = (char *)(src ? &ad->u.net.v4info.saddr :
3576 &ad->u.net.v4info.daddr);
3577 goto okay;
3578
3579 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
3580 case PF_INET6:
3581 ret = selinux_parse_skb_ipv6(skb, ad, proto);
3582 if (ret)
3583 goto parse_error;
3584 addrp = (char *)(src ? &ad->u.net.v6info.saddr :
3585 &ad->u.net.v6info.daddr);
3586 goto okay;
3587 #endif /* IPV6 */
3588 default:
3589 addrp = NULL;
3590 goto okay;
3591 }
3592
3593 parse_error:
3594 printk(KERN_WARNING
3595 "SELinux: failure in selinux_parse_skb(),"
3596 " unable to parse packet\n");
3597 return ret;
3598
3599 okay:
3600 if (_addrp)
3601 *_addrp = addrp;
3602 return 0;
3603 }
3604
3605 /**
3606 * selinux_skb_peerlbl_sid - Determine the peer label of a packet
3607 * @skb: the packet
3608 * @family: protocol family
3609 * @sid: the packet's peer label SID
3610 *
3611 * Description:
3612 * Check the various different forms of network peer labeling and determine
3613 * the peer label/SID for the packet; most of the magic actually occurs in
3614 * the security server function security_net_peersid_cmp(). The function
3615 * returns zero if the value in @sid is valid (although it may be SECSID_NULL)
3616 * or -EACCES if @sid is invalid due to inconsistencies with the different
3617 * peer labels.
3618 *
3619 */
3620 static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
3621 {
3622 int err;
3623 u32 xfrm_sid;
3624 u32 nlbl_sid;
3625 u32 nlbl_type;
3626
3627 selinux_skb_xfrm_sid(skb, &xfrm_sid);
3628 selinux_netlbl_skbuff_getsid(skb, family, &nlbl_type, &nlbl_sid);
3629
3630 err = security_net_peersid_resolve(nlbl_sid, nlbl_type, xfrm_sid, sid);
3631 if (unlikely(err)) {
3632 printk(KERN_WARNING
3633 "SELinux: failure in selinux_skb_peerlbl_sid(),"
3634 " unable to determine packet's peer label\n");
3635 return -EACCES;
3636 }
3637
3638 return 0;
3639 }
3640
3641 /* socket security operations */
3642 static int socket_has_perm(struct task_struct *task, struct socket *sock,
3643 u32 perms)
3644 {
3645 struct inode_security_struct *isec;
3646 struct avc_audit_data ad;
3647 u32 sid;
3648 int err = 0;
3649
3650 isec = SOCK_INODE(sock)->i_security;
3651
3652 if (isec->sid == SECINITSID_KERNEL)
3653 goto out;
3654 sid = task_sid(task);
3655
3656 AVC_AUDIT_DATA_INIT(&ad, NET);
3657 ad.u.net.sk = sock->sk;
3658 err = avc_has_perm(sid, isec->sid, isec->sclass, perms, &ad);
3659
3660 out:
3661 return err;
3662 }
3663
3664 static int selinux_socket_create(int family, int type,
3665 int protocol, int kern)
3666 {
3667 const struct cred *cred = current_cred();
3668 const struct task_security_struct *tsec = cred->security;
3669 u32 sid, newsid;
3670 u16 secclass;
3671 int err = 0;
3672
3673 if (kern)
3674 goto out;
3675
3676 sid = tsec->sid;
3677 newsid = tsec->sockcreate_sid ?: sid;
3678
3679 secclass = socket_type_to_security_class(family, type, protocol);
3680 err = avc_has_perm(sid, newsid, secclass, SOCKET__CREATE, NULL);
3681
3682 out:
3683 return err;
3684 }
3685
3686 static int selinux_socket_post_create(struct socket *sock, int family,
3687 int type, int protocol, int kern)
3688 {
3689 const struct cred *cred = current_cred();
3690 const struct task_security_struct *tsec = cred->security;
3691 struct inode_security_struct *isec;
3692 struct sk_security_struct *sksec;
3693 u32 sid, newsid;
3694 int err = 0;
3695
3696 sid = tsec->sid;
3697 newsid = tsec->sockcreate_sid;
3698
3699 isec = SOCK_INODE(sock)->i_security;
3700
3701 if (kern)
3702 isec->sid = SECINITSID_KERNEL;
3703 else if (newsid)
3704 isec->sid = newsid;
3705 else
3706 isec->sid = sid;
3707
3708 isec->sclass = socket_type_to_security_class(family, type, protocol);
3709 isec->initialized = 1;
3710
3711 if (sock->sk) {
3712 sksec = sock->sk->sk_security;
3713 sksec->sid = isec->sid;
3714 sksec->sclass = isec->sclass;
3715 err = selinux_netlbl_socket_post_create(sock->sk, family);
3716 }
3717
3718 return err;
3719 }
3720
3721 /* Range of port numbers used to automatically bind.
3722 Need to determine whether we should perform a name_bind
3723 permission check between the socket and the port number. */
3724
3725 static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
3726 {
3727 u16 family;
3728 int err;
3729
3730 err = socket_has_perm(current, sock, SOCKET__BIND);
3731 if (err)
3732 goto out;
3733
3734 /*
3735 * If PF_INET or PF_INET6, check name_bind permission for the port.
3736 * Multiple address binding for SCTP is not supported yet: we just
3737 * check the first address now.
3738 */
3739 family = sock->sk->sk_family;
3740 if (family == PF_INET || family == PF_INET6) {
3741 char *addrp;
3742 struct inode_security_struct *isec;
3743 struct avc_audit_data ad;
3744 struct sockaddr_in *addr4 = NULL;
3745 struct sockaddr_in6 *addr6 = NULL;
3746 unsigned short snum;
3747 struct sock *sk = sock->sk;
3748 u32 sid, node_perm;
3749
3750 isec = SOCK_INODE(sock)->i_security;
3751
3752 if (family == PF_INET) {
3753 addr4 = (struct sockaddr_in *)address;
3754 snum = ntohs(addr4->sin_port);
3755 addrp = (char *)&addr4->sin_addr.s_addr;
3756 } else {
3757 addr6 = (struct sockaddr_in6 *)address;
3758 snum = ntohs(addr6->sin6_port);
3759 addrp = (char *)&addr6->sin6_addr.s6_addr;
3760 }
3761
3762 if (snum) {
3763 int low, high;
3764
3765 inet_get_local_port_range(&low, &high);
3766
3767 if (snum < max(PROT_SOCK, low) || snum > high) {
3768 err = sel_netport_sid(sk->sk_protocol,
3769 snum, &sid);
3770 if (err)
3771 goto out;
3772 AVC_AUDIT_DATA_INIT(&ad, NET);
3773 ad.u.net.sport = htons(snum);
3774 ad.u.net.family = family;
3775 err = avc_has_perm(isec->sid, sid,
3776 isec->sclass,
3777 SOCKET__