Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm
[linux-2.6.git] / security / selinux / hooks.c
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 4
93
94 extern unsigned int policydb_loaded_version;
95 extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm);
96 extern int selinux_compat_net;
97 extern struct security_operations *security_ops;
98
99 /* SECMARK reference count */
100 atomic_t selinux_secmark_refcount = ATOMIC_INIT(0);
101
102 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
103 int selinux_enforcing;
104
105 static int __init enforcing_setup(char *str)
106 {
107         unsigned long enforcing;
108         if (!strict_strtoul(str, 0, &enforcing))
109                 selinux_enforcing = enforcing ? 1 : 0;
110         return 1;
111 }
112 __setup("enforcing=", enforcing_setup);
113 #endif
114
115 #ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
116 int selinux_enabled = CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE;
117
118 static int __init selinux_enabled_setup(char *str)
119 {
120         unsigned long enabled;
121         if (!strict_strtoul(str, 0, &enabled))
122                 selinux_enabled = enabled ? 1 : 0;
123         return 1;
124 }
125 __setup("selinux=", selinux_enabled_setup);
126 #else
127 int selinux_enabled = 1;
128 #endif
129
130
131 /*
132  * Minimal support for a secondary security module,
133  * just to allow the use of the capability module.
134  */
135 static struct security_operations *secondary_ops;
136
137 /* Lists of inode and superblock security structures initialized
138    before the policy was loaded. */
139 static LIST_HEAD(superblock_security_head);
140 static DEFINE_SPINLOCK(sb_security_lock);
141
142 static struct kmem_cache *sel_inode_cache;
143
144 /**
145  * selinux_secmark_enabled - Check to see if SECMARK is currently enabled
146  *
147  * Description:
148  * This function checks the SECMARK reference counter to see if any SECMARK
149  * targets are currently configured, if the reference counter is greater than
150  * zero SECMARK is considered to be enabled.  Returns true (1) if SECMARK is
151  * enabled, false (0) if SECMARK is disabled.
152  *
153  */
154 static int selinux_secmark_enabled(void)
155 {
156         return (atomic_read(&selinux_secmark_refcount) > 0);
157 }
158
159 /*
160  * initialise the security for the init task
161  */
162 static void cred_init_security(void)
163 {
164         struct cred *cred = (struct cred *) current->real_cred;
165         struct task_security_struct *tsec;
166
167         tsec = kzalloc(sizeof(struct task_security_struct), GFP_KERNEL);
168         if (!tsec)
169                 panic("SELinux:  Failed to initialize initial task.\n");
170
171         tsec->osid = tsec->sid = SECINITSID_KERNEL;
172         cred->security = tsec;
173 }
174
175 /*
176  * get the security ID of a set of credentials
177  */
178 static inline u32 cred_sid(const struct cred *cred)
179 {
180         const struct task_security_struct *tsec;
181
182         tsec = cred->security;
183         return tsec->sid;
184 }
185
186 /*
187  * get the objective security ID of a task
188  */
189 static inline u32 task_sid(const struct task_struct *task)
190 {
191         u32 sid;
192
193         rcu_read_lock();
194         sid = cred_sid(__task_cred(task));
195         rcu_read_unlock();
196         return sid;
197 }
198
199 /*
200  * get the subjective security ID of the current task
201  */
202 static inline u32 current_sid(void)
203 {
204         const struct task_security_struct *tsec = current_cred()->security;
205
206         return tsec->sid;
207 }
208
209 /* Allocate and free functions for each kind of security blob. */
210
211 static int inode_alloc_security(struct inode *inode)
212 {
213         struct inode_security_struct *isec;
214         u32 sid = current_sid();
215
216         isec = kmem_cache_zalloc(sel_inode_cache, GFP_NOFS);
217         if (!isec)
218                 return -ENOMEM;
219
220         mutex_init(&isec->lock);
221         INIT_LIST_HEAD(&isec->list);
222         isec->inode = inode;
223         isec->sid = SECINITSID_UNLABELED;
224         isec->sclass = SECCLASS_FILE;
225         isec->task_sid = sid;
226         inode->i_security = isec;
227
228         return 0;
229 }
230
231 static void inode_free_security(struct inode *inode)
232 {
233         struct inode_security_struct *isec = inode->i_security;
234         struct superblock_security_struct *sbsec = inode->i_sb->s_security;
235
236         spin_lock(&sbsec->isec_lock);
237         if (!list_empty(&isec->list))
238                 list_del_init(&isec->list);
239         spin_unlock(&sbsec->isec_lock);
240
241         inode->i_security = NULL;
242         kmem_cache_free(sel_inode_cache, isec);
243 }
244
245 static int file_alloc_security(struct file *file)
246 {
247         struct file_security_struct *fsec;
248         u32 sid = current_sid();
249
250         fsec = kzalloc(sizeof(struct file_security_struct), GFP_KERNEL);
251         if (!fsec)
252                 return -ENOMEM;
253
254         fsec->sid = sid;
255         fsec->fown_sid = sid;
256         file->f_security = fsec;
257
258         return 0;
259 }
260
261 static void file_free_security(struct file *file)
262 {
263         struct file_security_struct *fsec = file->f_security;
264         file->f_security = NULL;
265         kfree(fsec);
266 }
267
268 static int superblock_alloc_security(struct super_block *sb)
269 {
270         struct superblock_security_struct *sbsec;
271
272         sbsec = kzalloc(sizeof(struct superblock_security_struct), GFP_KERNEL);
273         if (!sbsec)
274                 return -ENOMEM;
275
276         mutex_init(&sbsec->lock);
277         INIT_LIST_HEAD(&sbsec->list);
278         INIT_LIST_HEAD(&sbsec->isec_head);
279         spin_lock_init(&sbsec->isec_lock);
280         sbsec->sb = sb;
281         sbsec->sid = SECINITSID_UNLABELED;
282         sbsec->def_sid = SECINITSID_FILE;
283         sbsec->mntpoint_sid = SECINITSID_UNLABELED;
284         sb->s_security = sbsec;
285
286         return 0;
287 }
288
289 static void superblock_free_security(struct super_block *sb)
290 {
291         struct superblock_security_struct *sbsec = sb->s_security;
292
293         spin_lock(&sb_security_lock);
294         if (!list_empty(&sbsec->list))
295                 list_del_init(&sbsec->list);
296         spin_unlock(&sb_security_lock);
297
298         sb->s_security = NULL;
299         kfree(sbsec);
300 }
301
302 static int sk_alloc_security(struct sock *sk, int family, gfp_t priority)
303 {
304         struct sk_security_struct *ssec;
305
306         ssec = kzalloc(sizeof(*ssec), priority);
307         if (!ssec)
308                 return -ENOMEM;
309
310         ssec->peer_sid = SECINITSID_UNLABELED;
311         ssec->sid = SECINITSID_UNLABELED;
312         sk->sk_security = ssec;
313
314         selinux_netlbl_sk_security_reset(ssec, family);
315
316         return 0;
317 }
318
319 static void sk_free_security(struct sock *sk)
320 {
321         struct sk_security_struct *ssec = sk->sk_security;
322
323         sk->sk_security = NULL;
324         selinux_netlbl_sk_security_free(ssec);
325         kfree(ssec);
326 }
327
328 /* The security server must be initialized before
329    any labeling or access decisions can be provided. */
330 extern int ss_initialized;
331
332 /* The file system's label must be initialized prior to use. */
333
334 static char *labeling_behaviors[6] = {
335         "uses xattr",
336         "uses transition SIDs",
337         "uses task SIDs",
338         "uses genfs_contexts",
339         "not configured for labeling",
340         "uses mountpoint labeling",
341 };
342
343 static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry);
344
345 static inline int inode_doinit(struct inode *inode)
346 {
347         return inode_doinit_with_dentry(inode, NULL);
348 }
349
350 enum {
351         Opt_error = -1,
352         Opt_context = 1,
353         Opt_fscontext = 2,
354         Opt_defcontext = 3,
355         Opt_rootcontext = 4,
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_error, NULL},
364 };
365
366 #define SEL_MOUNT_FAIL_MSG "SELinux:  duplicate or incompatible mount options\n"
367
368 static int may_context_mount_sb_relabel(u32 sid,
369                         struct superblock_security_struct *sbsec,
370                         const struct cred *cred)
371 {
372         const struct task_security_struct *tsec = cred->security;
373         int rc;
374
375         rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
376                           FILESYSTEM__RELABELFROM, NULL);
377         if (rc)
378                 return rc;
379
380         rc = avc_has_perm(tsec->sid, sid, SECCLASS_FILESYSTEM,
381                           FILESYSTEM__RELABELTO, NULL);
382         return rc;
383 }
384
385 static int may_context_mount_inode_relabel(u32 sid,
386                         struct superblock_security_struct *sbsec,
387                         const struct cred *cred)
388 {
389         const struct task_security_struct *tsec = cred->security;
390         int rc;
391         rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
392                           FILESYSTEM__RELABELFROM, NULL);
393         if (rc)
394                 return rc;
395
396         rc = avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM,
397                           FILESYSTEM__ASSOCIATE, NULL);
398         return rc;
399 }
400
401 static int sb_finish_set_opts(struct super_block *sb)
402 {
403         struct superblock_security_struct *sbsec = sb->s_security;
404         struct dentry *root = sb->s_root;
405         struct inode *root_inode = root->d_inode;
406         int rc = 0;
407
408         if (sbsec->behavior == SECURITY_FS_USE_XATTR) {
409                 /* Make sure that the xattr handler exists and that no
410                    error other than -ENODATA is returned by getxattr on
411                    the root directory.  -ENODATA is ok, as this may be
412                    the first boot of the SELinux kernel before we have
413                    assigned xattr values to the filesystem. */
414                 if (!root_inode->i_op->getxattr) {
415                         printk(KERN_WARNING "SELinux: (dev %s, type %s) has no "
416                                "xattr support\n", sb->s_id, sb->s_type->name);
417                         rc = -EOPNOTSUPP;
418                         goto out;
419                 }
420                 rc = root_inode->i_op->getxattr(root, XATTR_NAME_SELINUX, NULL, 0);
421                 if (rc < 0 && rc != -ENODATA) {
422                         if (rc == -EOPNOTSUPP)
423                                 printk(KERN_WARNING "SELinux: (dev %s, type "
424                                        "%s) has no security xattr handler\n",
425                                        sb->s_id, sb->s_type->name);
426                         else
427                                 printk(KERN_WARNING "SELinux: (dev %s, type "
428                                        "%s) getxattr errno %d\n", sb->s_id,
429                                        sb->s_type->name, -rc);
430                         goto out;
431                 }
432         }
433
434         sbsec->initialized = 1;
435
436         if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
437                 printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n",
438                        sb->s_id, sb->s_type->name);
439         else
440                 printk(KERN_DEBUG "SELinux: initialized (dev %s, type %s), %s\n",
441                        sb->s_id, sb->s_type->name,
442                        labeling_behaviors[sbsec->behavior-1]);
443
444         /* Initialize the root inode. */
445         rc = inode_doinit_with_dentry(root_inode, root);
446
447         /* Initialize any other inodes associated with the superblock, e.g.
448            inodes created prior to initial policy load or inodes created
449            during get_sb by a pseudo filesystem that directly
450            populates itself. */
451         spin_lock(&sbsec->isec_lock);
452 next_inode:
453         if (!list_empty(&sbsec->isec_head)) {
454                 struct inode_security_struct *isec =
455                                 list_entry(sbsec->isec_head.next,
456                                            struct inode_security_struct, list);
457                 struct inode *inode = isec->inode;
458                 spin_unlock(&sbsec->isec_lock);
459                 inode = igrab(inode);
460                 if (inode) {
461                         if (!IS_PRIVATE(inode))
462                                 inode_doinit(inode);
463                         iput(inode);
464                 }
465                 spin_lock(&sbsec->isec_lock);
466                 list_del_init(&isec->list);
467                 goto next_inode;
468         }
469         spin_unlock(&sbsec->isec_lock);
470 out:
471         return rc;
472 }
473
474 /*
475  * This function should allow an FS to ask what it's mount security
476  * options were so it can use those later for submounts, displaying
477  * mount options, or whatever.
478  */
479 static int selinux_get_mnt_opts(const struct super_block *sb,
480                                 struct security_mnt_opts *opts)
481 {
482         int rc = 0, i;
483         struct superblock_security_struct *sbsec = sb->s_security;
484         char *context = NULL;
485         u32 len;
486         char tmp;
487
488         security_init_mnt_opts(opts);
489
490         if (!sbsec->initialized)
491                 return -EINVAL;
492
493         if (!ss_initialized)
494                 return -EINVAL;
495
496         /*
497          * if we ever use sbsec flags for anything other than tracking mount
498          * settings this is going to need a mask
499          */
500         tmp = sbsec->flags;
501         /* count the number of mount options for this sb */
502         for (i = 0; i < 8; i++) {
503                 if (tmp & 0x01)
504                         opts->num_mnt_opts++;
505                 tmp >>= 1;
506         }
507
508         opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC);
509         if (!opts->mnt_opts) {
510                 rc = -ENOMEM;
511                 goto out_free;
512         }
513
514         opts->mnt_opts_flags = kcalloc(opts->num_mnt_opts, sizeof(int), GFP_ATOMIC);
515         if (!opts->mnt_opts_flags) {
516                 rc = -ENOMEM;
517                 goto out_free;
518         }
519
520         i = 0;
521         if (sbsec->flags & FSCONTEXT_MNT) {
522                 rc = security_sid_to_context(sbsec->sid, &context, &len);
523                 if (rc)
524                         goto out_free;
525                 opts->mnt_opts[i] = context;
526                 opts->mnt_opts_flags[i++] = FSCONTEXT_MNT;
527         }
528         if (sbsec->flags & CONTEXT_MNT) {
529                 rc = security_sid_to_context(sbsec->mntpoint_sid, &context, &len);
530                 if (rc)
531                         goto out_free;
532                 opts->mnt_opts[i] = context;
533                 opts->mnt_opts_flags[i++] = CONTEXT_MNT;
534         }
535         if (sbsec->flags & DEFCONTEXT_MNT) {
536                 rc = security_sid_to_context(sbsec->def_sid, &context, &len);
537                 if (rc)
538                         goto out_free;
539                 opts->mnt_opts[i] = context;
540                 opts->mnt_opts_flags[i++] = DEFCONTEXT_MNT;
541         }
542         if (sbsec->flags & ROOTCONTEXT_MNT) {
543                 struct inode *root = sbsec->sb->s_root->d_inode;
544                 struct inode_security_struct *isec = root->i_security;
545
546                 rc = security_sid_to_context(isec->sid, &context, &len);
547                 if (rc)
548                         goto out_free;
549                 opts->mnt_opts[i] = context;
550                 opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT;
551         }
552
553         BUG_ON(i != opts->num_mnt_opts);
554
555         return 0;
556
557 out_free:
558         security_free_mnt_opts(opts);
559         return rc;
560 }
561
562 static int bad_option(struct superblock_security_struct *sbsec, char flag,
563                       u32 old_sid, u32 new_sid)
564 {
565         /* check if the old mount command had the same options */
566         if (sbsec->initialized)
567                 if (!(sbsec->flags & flag) ||
568                     (old_sid != new_sid))
569                         return 1;
570
571         /* check if we were passed the same options twice,
572          * aka someone passed context=a,context=b
573          */
574         if (!sbsec->initialized)
575                 if (sbsec->flags & flag)
576                         return 1;
577         return 0;
578 }
579
580 /*
581  * Allow filesystems with binary mount data to explicitly set mount point
582  * labeling information.
583  */
584 static int selinux_set_mnt_opts(struct super_block *sb,
585                                 struct security_mnt_opts *opts)
586 {
587         const struct cred *cred = current_cred();
588         int rc = 0, i;
589         struct superblock_security_struct *sbsec = sb->s_security;
590         const char *name = sb->s_type->name;
591         struct inode *inode = sbsec->sb->s_root->d_inode;
592         struct inode_security_struct *root_isec = inode->i_security;
593         u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
594         u32 defcontext_sid = 0;
595         char **mount_options = opts->mnt_opts;
596         int *flags = opts->mnt_opts_flags;
597         int num_opts = opts->num_mnt_opts;
598
599         mutex_lock(&sbsec->lock);
600
601         if (!ss_initialized) {
602                 if (!num_opts) {
603                         /* Defer initialization until selinux_complete_init,
604                            after the initial policy is loaded and the security
605                            server is ready to handle calls. */
606                         spin_lock(&sb_security_lock);
607                         if (list_empty(&sbsec->list))
608                                 list_add(&sbsec->list, &superblock_security_head);
609                         spin_unlock(&sb_security_lock);
610                         goto out;
611                 }
612                 rc = -EINVAL;
613                 printk(KERN_WARNING "SELinux: Unable to set superblock options "
614                         "before the security server is initialized\n");
615                 goto out;
616         }
617
618         /*
619          * Binary mount data FS will come through this function twice.  Once
620          * from an explicit call and once from the generic calls from the vfs.
621          * Since the generic VFS calls will not contain any security mount data
622          * we need to skip the double mount verification.
623          *
624          * This does open a hole in which we will not notice if the first
625          * mount using this sb set explict options and a second mount using
626          * this sb does not set any security options.  (The first options
627          * will be used for both mounts)
628          */
629         if (sbsec->initialized && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
630             && (num_opts == 0))
631                 goto out;
632
633         /*
634          * parse the mount options, check if they are valid sids.
635          * also check if someone is trying to mount the same sb more
636          * than once with different security options.
637          */
638         for (i = 0; i < num_opts; i++) {
639                 u32 sid;
640                 rc = security_context_to_sid(mount_options[i],
641                                              strlen(mount_options[i]), &sid);
642                 if (rc) {
643                         printk(KERN_WARNING "SELinux: security_context_to_sid"
644                                "(%s) failed for (dev %s, type %s) errno=%d\n",
645                                mount_options[i], sb->s_id, name, rc);
646                         goto out;
647                 }
648                 switch (flags[i]) {
649                 case FSCONTEXT_MNT:
650                         fscontext_sid = sid;
651
652                         if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
653                                         fscontext_sid))
654                                 goto out_double_mount;
655
656                         sbsec->flags |= FSCONTEXT_MNT;
657                         break;
658                 case CONTEXT_MNT:
659                         context_sid = sid;
660
661                         if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
662                                         context_sid))
663                                 goto out_double_mount;
664
665                         sbsec->flags |= CONTEXT_MNT;
666                         break;
667                 case ROOTCONTEXT_MNT:
668                         rootcontext_sid = sid;
669
670                         if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
671                                         rootcontext_sid))
672                                 goto out_double_mount;
673
674                         sbsec->flags |= ROOTCONTEXT_MNT;
675
676                         break;
677                 case DEFCONTEXT_MNT:
678                         defcontext_sid = sid;
679
680                         if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
681                                         defcontext_sid))
682                                 goto out_double_mount;
683
684                         sbsec->flags |= DEFCONTEXT_MNT;
685
686                         break;
687                 default:
688                         rc = -EINVAL;
689                         goto out;
690                 }
691         }
692
693         if (sbsec->initialized) {
694                 /* previously mounted with options, but not on this attempt? */
695                 if (sbsec->flags && !num_opts)
696                         goto out_double_mount;
697                 rc = 0;
698                 goto out;
699         }
700
701         if (strcmp(sb->s_type->name, "proc") == 0)
702                 sbsec->proc = 1;
703
704         /* Determine the labeling behavior to use for this filesystem type. */
705         rc = security_fs_use(sbsec->proc ? "proc" : sb->s_type->name, &sbsec->behavior, &sbsec->sid);
706         if (rc) {
707                 printk(KERN_WARNING "%s: security_fs_use(%s) returned %d\n",
708                        __func__, sb->s_type->name, rc);
709                 goto out;
710         }
711
712         /* sets the context of the superblock for the fs being mounted. */
713         if (fscontext_sid) {
714                 rc = may_context_mount_sb_relabel(fscontext_sid, sbsec, cred);
715                 if (rc)
716                         goto out;
717
718                 sbsec->sid = fscontext_sid;
719         }
720
721         /*
722          * Switch to using mount point labeling behavior.
723          * sets the label used on all file below the mountpoint, and will set
724          * the superblock context if not already set.
725          */
726         if (context_sid) {
727                 if (!fscontext_sid) {
728                         rc = may_context_mount_sb_relabel(context_sid, sbsec,
729                                                           cred);
730                         if (rc)
731                                 goto out;
732                         sbsec->sid = context_sid;
733                 } else {
734                         rc = may_context_mount_inode_relabel(context_sid, sbsec,
735                                                              cred);
736                         if (rc)
737                                 goto out;
738                 }
739                 if (!rootcontext_sid)
740                         rootcontext_sid = context_sid;
741
742                 sbsec->mntpoint_sid = context_sid;
743                 sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
744         }
745
746         if (rootcontext_sid) {
747                 rc = may_context_mount_inode_relabel(rootcontext_sid, sbsec,
748                                                      cred);
749                 if (rc)
750                         goto out;
751
752                 root_isec->sid = rootcontext_sid;
753                 root_isec->initialized = 1;
754         }
755
756         if (defcontext_sid) {
757                 if (sbsec->behavior != SECURITY_FS_USE_XATTR) {
758                         rc = -EINVAL;
759                         printk(KERN_WARNING "SELinux: defcontext option is "
760                                "invalid for this filesystem type\n");
761                         goto out;
762                 }
763
764                 if (defcontext_sid != sbsec->def_sid) {
765                         rc = may_context_mount_inode_relabel(defcontext_sid,
766                                                              sbsec, cred);
767                         if (rc)
768                                 goto out;
769                 }
770
771                 sbsec->def_sid = defcontext_sid;
772         }
773
774         rc = sb_finish_set_opts(sb);
775 out:
776         mutex_unlock(&sbsec->lock);
777         return rc;
778 out_double_mount:
779         rc = -EINVAL;
780         printk(KERN_WARNING "SELinux: mount invalid.  Same superblock, different "
781                "security settings for (dev %s, type %s)\n", sb->s_id, name);
782         goto out;
783 }
784
785 static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
786                                         struct super_block *newsb)
787 {
788         const struct superblock_security_struct *oldsbsec = oldsb->s_security;
789         struct superblock_security_struct *newsbsec = newsb->s_security;
790
791         int set_fscontext =     (oldsbsec->flags & FSCONTEXT_MNT);
792         int set_context =       (oldsbsec->flags & CONTEXT_MNT);
793         int set_rootcontext =   (oldsbsec->flags & ROOTCONTEXT_MNT);
794
795         /*
796          * if the parent was able to be mounted it clearly had no special lsm
797          * mount options.  thus we can safely put this sb on the list and deal
798          * with it later
799          */
800         if (!ss_initialized) {
801                 spin_lock(&sb_security_lock);
802                 if (list_empty(&newsbsec->list))
803                         list_add(&newsbsec->list, &superblock_security_head);
804                 spin_unlock(&sb_security_lock);
805                 return;
806         }
807
808         /* how can we clone if the old one wasn't set up?? */
809         BUG_ON(!oldsbsec->initialized);
810
811         /* if fs is reusing a sb, just let its options stand... */
812         if (newsbsec->initialized)
813                 return;
814
815         mutex_lock(&newsbsec->lock);
816
817         newsbsec->flags = oldsbsec->flags;
818
819         newsbsec->sid = oldsbsec->sid;
820         newsbsec->def_sid = oldsbsec->def_sid;
821         newsbsec->behavior = oldsbsec->behavior;
822
823         if (set_context) {
824                 u32 sid = oldsbsec->mntpoint_sid;
825
826                 if (!set_fscontext)
827                         newsbsec->sid = sid;
828                 if (!set_rootcontext) {
829                         struct inode *newinode = newsb->s_root->d_inode;
830                         struct inode_security_struct *newisec = newinode->i_security;
831                         newisec->sid = sid;
832                 }
833                 newsbsec->mntpoint_sid = sid;
834         }
835         if (set_rootcontext) {
836                 const struct inode *oldinode = oldsb->s_root->d_inode;
837                 const struct inode_security_struct *oldisec = oldinode->i_security;
838                 struct inode *newinode = newsb->s_root->d_inode;
839                 struct inode_security_struct *newisec = newinode->i_security;
840
841                 newisec->sid = oldisec->sid;
842         }
843
844         sb_finish_set_opts(newsb);
845         mutex_unlock(&newsbsec->lock);
846 }
847
848 static int selinux_parse_opts_str(char *options,
849                                   struct security_mnt_opts *opts)
850 {
851         char *p;
852         char *context = NULL, *defcontext = NULL;
853         char *fscontext = NULL, *rootcontext = NULL;
854         int rc, num_mnt_opts = 0;
855
856         opts->num_mnt_opts = 0;
857
858         /* Standard string-based options. */
859         while ((p = strsep(&options, "|")) != NULL) {
860                 int token;
861                 substring_t args[MAX_OPT_ARGS];
862
863                 if (!*p)
864                         continue;
865
866                 token = match_token(p, tokens, args);
867
868                 switch (token) {
869                 case Opt_context:
870                         if (context || defcontext) {
871                                 rc = -EINVAL;
872                                 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
873                                 goto out_err;
874                         }
875                         context = match_strdup(&args[0]);
876                         if (!context) {
877                                 rc = -ENOMEM;
878                                 goto out_err;
879                         }
880                         break;
881
882                 case Opt_fscontext:
883                         if (fscontext) {
884                                 rc = -EINVAL;
885                                 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
886                                 goto out_err;
887                         }
888                         fscontext = match_strdup(&args[0]);
889                         if (!fscontext) {
890                                 rc = -ENOMEM;
891                                 goto out_err;
892                         }
893                         break;
894
895                 case Opt_rootcontext:
896                         if (rootcontext) {
897                                 rc = -EINVAL;
898                                 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
899                                 goto out_err;
900                         }
901                         rootcontext = match_strdup(&args[0]);
902                         if (!rootcontext) {
903                                 rc = -ENOMEM;
904                                 goto out_err;
905                         }
906                         break;
907
908                 case Opt_defcontext:
909                         if (context || defcontext) {
910                                 rc = -EINVAL;
911                                 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
912                                 goto out_err;
913                         }
914                         defcontext = match_strdup(&args[0]);
915                         if (!defcontext) {
916                                 rc = -ENOMEM;
917                                 goto out_err;
918                         }
919                         break;
920
921                 default:
922                         rc = -EINVAL;
923                         printk(KERN_WARNING "SELinux:  unknown mount option\n");
924                         goto out_err;
925
926                 }
927         }
928
929         rc = -ENOMEM;
930         opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_ATOMIC);
931         if (!opts->mnt_opts)
932                 goto out_err;
933
934         opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int), GFP_ATOMIC);
935         if (!opts->mnt_opts_flags) {
936                 kfree(opts->mnt_opts);
937                 goto out_err;
938         }
939
940         if (fscontext) {
941                 opts->mnt_opts[num_mnt_opts] = fscontext;
942                 opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
943         }
944         if (context) {
945                 opts->mnt_opts[num_mnt_opts] = context;
946                 opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
947         }
948         if (rootcontext) {
949                 opts->mnt_opts[num_mnt_opts] = rootcontext;
950                 opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
951         }
952         if (defcontext) {
953                 opts->mnt_opts[num_mnt_opts] = defcontext;
954                 opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
955         }
956
957         opts->num_mnt_opts = num_mnt_opts;
958         return 0;
959
960 out_err:
961         kfree(context);
962         kfree(defcontext);
963         kfree(fscontext);
964         kfree(rootcontext);
965         return rc;
966 }
967 /*
968  * string mount options parsing and call set the sbsec
969  */
970 static int superblock_doinit(struct super_block *sb, void *data)
971 {
972         int rc = 0;
973         char *options = data;
974         struct security_mnt_opts opts;
975
976         security_init_mnt_opts(&opts);
977
978         if (!data)
979                 goto out;
980
981         BUG_ON(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA);
982
983         rc = selinux_parse_opts_str(options, &opts);
984         if (rc)
985                 goto out_err;
986
987 out:
988         rc = selinux_set_mnt_opts(sb, &opts);
989
990 out_err:
991         security_free_mnt_opts(&opts);
992         return rc;
993 }
994
995 static void selinux_write_opts(struct seq_file *m,
996                                struct security_mnt_opts *opts)
997 {
998         int i;
999         char *prefix;
1000
1001         for (i = 0; i < opts->num_mnt_opts; i++) {
1002                 char *has_comma = strchr(opts->mnt_opts[i], ',');
1003
1004                 switch (opts->mnt_opts_flags[i]) {
1005                 case CONTEXT_MNT:
1006                         prefix = CONTEXT_STR;
1007                         break;
1008                 case FSCONTEXT_MNT:
1009                         prefix = FSCONTEXT_STR;
1010                         break;
1011                 case ROOTCONTEXT_MNT:
1012                         prefix = ROOTCONTEXT_STR;
1013                         break;
1014                 case DEFCONTEXT_MNT:
1015                         prefix = DEFCONTEXT_STR;
1016                         break;
1017                 default:
1018                         BUG();
1019                 };
1020                 /* we need a comma before each option */
1021                 seq_putc(m, ',');
1022                 seq_puts(m, prefix);
1023                 if (has_comma)
1024                         seq_putc(m, '\"');
1025                 seq_puts(m, opts->mnt_opts[i]);
1026                 if (has_comma)
1027                         seq_putc(m, '\"');
1028         }
1029 }
1030
1031 static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
1032 {
1033         struct security_mnt_opts opts;
1034         int rc;
1035
1036         rc = selinux_get_mnt_opts(sb, &opts);
1037         if (rc) {
1038                 /* before policy load we may get EINVAL, don't show anything */
1039                 if (rc == -EINVAL)
1040                         rc = 0;
1041                 return rc;
1042         }
1043
1044         selinux_write_opts(m, &opts);
1045
1046         security_free_mnt_opts(&opts);
1047
1048         return rc;
1049 }
1050
1051 static inline u16 inode_mode_to_security_class(umode_t mode)
1052 {
1053         switch (mode & S_IFMT) {
1054         case S_IFSOCK:
1055                 return SECCLASS_SOCK_FILE;
1056         case S_IFLNK:
1057                 return SECCLASS_LNK_FILE;
1058         case S_IFREG:
1059                 return SECCLASS_FILE;
1060         case S_IFBLK:
1061                 return SECCLASS_BLK_FILE;
1062         case S_IFDIR:
1063                 return SECCLASS_DIR;
1064         case S_IFCHR:
1065                 return SECCLASS_CHR_FILE;
1066         case S_IFIFO:
1067                 return SECCLASS_FIFO_FILE;
1068
1069         }
1070
1071         return SECCLASS_FILE;
1072 }
1073
1074 static inline int default_protocol_stream(int protocol)
1075 {
1076         return (protocol == IPPROTO_IP || protocol == IPPROTO_TCP);
1077 }
1078
1079 static inline int default_protocol_dgram(int protocol)
1080 {
1081         return (protocol == IPPROTO_IP || protocol == IPPROTO_UDP);
1082 }
1083
1084 static inline u16 socket_type_to_security_class(int family, int type, int protocol)
1085 {
1086         switch (family) {
1087         case PF_UNIX:
1088                 switch (type) {
1089                 case SOCK_STREAM:
1090                 case SOCK_SEQPACKET:
1091                         return SECCLASS_UNIX_STREAM_SOCKET;
1092                 case SOCK_DGRAM:
1093                         return SECCLASS_UNIX_DGRAM_SOCKET;
1094                 }
1095                 break;
1096         case PF_INET:
1097         case PF_INET6:
1098                 switch (type) {
1099                 case SOCK_STREAM:
1100                         if (default_protocol_stream(protocol))
1101                                 return SECCLASS_TCP_SOCKET;
1102                         else
1103                                 return SECCLASS_RAWIP_SOCKET;
1104                 case SOCK_DGRAM:
1105                         if (default_protocol_dgram(protocol))
1106                                 return SECCLASS_UDP_SOCKET;
1107                         else
1108                                 return SECCLASS_RAWIP_SOCKET;
1109                 case SOCK_DCCP:
1110                         return SECCLASS_DCCP_SOCKET;
1111                 default:
1112                         return SECCLASS_RAWIP_SOCKET;
1113                 }
1114                 break;
1115         case PF_NETLINK:
1116                 switch (protocol) {
1117                 case NETLINK_ROUTE:
1118                         return SECCLASS_NETLINK_ROUTE_SOCKET;
1119                 case NETLINK_FIREWALL:
1120                         return SECCLASS_NETLINK_FIREWALL_SOCKET;
1121                 case NETLINK_INET_DIAG:
1122                         return SECCLASS_NETLINK_TCPDIAG_SOCKET;
1123                 case NETLINK_NFLOG:
1124                         return SECCLASS_NETLINK_NFLOG_SOCKET;
1125                 case NETLINK_XFRM:
1126                         return SECCLASS_NETLINK_XFRM_SOCKET;
1127                 case NETLINK_SELINUX:
1128                         return SECCLASS_NETLINK_SELINUX_SOCKET;
1129                 case NETLINK_AUDIT:
1130                         return SECCLASS_NETLINK_AUDIT_SOCKET;
1131                 case NETLINK_IP6_FW:
1132                         return SECCLASS_NETLINK_IP6FW_SOCKET;
1133                 case NETLINK_DNRTMSG:
1134                         return SECCLASS_NETLINK_DNRT_SOCKET;
1135                 case NETLINK_KOBJECT_UEVENT:
1136                         return SECCLASS_NETLINK_KOBJECT_UEVENT_SOCKET;
1137                 default:
1138                         return SECCLASS_NETLINK_SOCKET;
1139                 }
1140         case PF_PACKET:
1141                 return SECCLASS_PACKET_SOCKET;
1142         case PF_KEY:
1143                 return SECCLASS_KEY_SOCKET;
1144         case PF_APPLETALK:
1145                 return SECCLASS_APPLETALK_SOCKET;
1146         }
1147
1148         return SECCLASS_SOCKET;
1149 }
1150
1151 #ifdef CONFIG_PROC_FS
1152 static int selinux_proc_get_sid(struct proc_dir_entry *de,
1153                                 u16 tclass,
1154                                 u32 *sid)
1155 {
1156         int buflen, rc;
1157         char *buffer, *path, *end;
1158
1159         buffer = (char *)__get_free_page(GFP_KERNEL);
1160         if (!buffer)
1161                 return -ENOMEM;
1162
1163         buflen = PAGE_SIZE;
1164         end = buffer+buflen;
1165         *--end = '\0';
1166         buflen--;
1167         path = end-1;
1168         *path = '/';
1169         while (de && de != de->parent) {
1170                 buflen -= de->namelen + 1;
1171                 if (buflen < 0)
1172                         break;
1173                 end -= de->namelen;
1174                 memcpy(end, de->name, de->namelen);
1175                 *--end = '/';
1176                 path = end;
1177                 de = de->parent;
1178         }
1179         rc = security_genfs_sid("proc", path, tclass, sid);
1180         free_page((unsigned long)buffer);
1181         return rc;
1182 }
1183 #else
1184 static int selinux_proc_get_sid(struct proc_dir_entry *de,
1185                                 u16 tclass,
1186                                 u32 *sid)
1187 {
1188         return -EINVAL;
1189 }
1190 #endif
1191
1192 /* The inode's security attributes must be initialized before first use. */
1193 static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry)
1194 {
1195         struct superblock_security_struct *sbsec = NULL;
1196         struct inode_security_struct *isec = inode->i_security;
1197         u32 sid;
1198         struct dentry *dentry;
1199 #define INITCONTEXTLEN 255
1200         char *context = NULL;
1201         unsigned len = 0;
1202         int rc = 0;
1203
1204         if (isec->initialized)
1205                 goto out;
1206
1207         mutex_lock(&isec->lock);
1208         if (isec->initialized)
1209                 goto out_unlock;
1210
1211         sbsec = inode->i_sb->s_security;
1212         if (!sbsec->initialized) {
1213                 /* Defer initialization until selinux_complete_init,
1214                    after the initial policy is loaded and the security
1215                    server is ready to handle calls. */
1216                 spin_lock(&sbsec->isec_lock);
1217                 if (list_empty(&isec->list))
1218                         list_add(&isec->list, &sbsec->isec_head);
1219                 spin_unlock(&sbsec->isec_lock);
1220                 goto out_unlock;
1221         }
1222
1223         switch (sbsec->behavior) {
1224         case SECURITY_FS_USE_XATTR:
1225                 if (!inode->i_op->getxattr) {
1226                         isec->sid = sbsec->def_sid;
1227                         break;
1228                 }
1229
1230                 /* Need a dentry, since the xattr API requires one.
1231                    Life would be simpler if we could just pass the inode. */
1232                 if (opt_dentry) {
1233                         /* Called from d_instantiate or d_splice_alias. */
1234                         dentry = dget(opt_dentry);
1235                 } else {
1236                         /* Called from selinux_complete_init, try to find a dentry. */
1237                         dentry = d_find_alias(inode);
1238                 }
1239                 if (!dentry) {
1240                         printk(KERN_WARNING "SELinux: %s:  no dentry for dev=%s "
1241                                "ino=%ld\n", __func__, inode->i_sb->s_id,
1242                                inode->i_ino);
1243                         goto out_unlock;
1244                 }
1245
1246                 len = INITCONTEXTLEN;
1247                 context = kmalloc(len, GFP_NOFS);
1248                 if (!context) {
1249                         rc = -ENOMEM;
1250                         dput(dentry);
1251                         goto out_unlock;
1252                 }
1253                 rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
1254                                            context, len);
1255                 if (rc == -ERANGE) {
1256                         /* Need a larger buffer.  Query for the right size. */
1257                         rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
1258                                                    NULL, 0);
1259                         if (rc < 0) {
1260                                 dput(dentry);
1261                                 goto out_unlock;
1262                         }
1263                         kfree(context);
1264                         len = rc;
1265                         context = kmalloc(len, GFP_NOFS);
1266                         if (!context) {
1267                                 rc = -ENOMEM;
1268                                 dput(dentry);
1269                                 goto out_unlock;
1270                         }
1271                         rc = inode->i_op->getxattr(dentry,
1272                                                    XATTR_NAME_SELINUX,
1273                                                    context, len);
1274                 }
1275                 dput(dentry);
1276                 if (rc < 0) {
1277                         if (rc != -ENODATA) {
1278                                 printk(KERN_WARNING "SELinux: %s:  getxattr returned "
1279                                        "%d for dev=%s ino=%ld\n", __func__,
1280                                        -rc, inode->i_sb->s_id, inode->i_ino);
1281                                 kfree(context);
1282                                 goto out_unlock;
1283                         }
1284                         /* Map ENODATA to the default file SID */
1285                         sid = sbsec->def_sid;
1286                         rc = 0;
1287                 } else {
1288                         rc = security_context_to_sid_default(context, rc, &sid,
1289                                                              sbsec->def_sid,
1290                                                              GFP_NOFS);
1291                         if (rc) {
1292                                 printk(KERN_WARNING "SELinux: %s:  context_to_sid(%s) "
1293                                        "returned %d for dev=%s ino=%ld\n",
1294                                        __func__, context, -rc,
1295                                        inode->i_sb->s_id, inode->i_ino);
1296                                 kfree(context);
1297                                 /* Leave with the unlabeled SID */
1298                                 rc = 0;
1299                                 break;
1300                         }
1301                 }
1302                 kfree(context);
1303                 isec->sid = sid;
1304                 break;
1305         case SECURITY_FS_USE_TASK:
1306                 isec->sid = isec->task_sid;
1307                 break;
1308         case SECURITY_FS_USE_TRANS:
1309                 /* Default to the fs SID. */
1310                 isec->sid = sbsec->sid;
1311
1312                 /* Try to obtain a transition SID. */
1313                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1314                 rc = security_transition_sid(isec->task_sid,
1315                                              sbsec->sid,
1316                                              isec->sclass,
1317                                              &sid);
1318                 if (rc)
1319                         goto out_unlock;
1320                 isec->sid = sid;
1321                 break;
1322         case SECURITY_FS_USE_MNTPOINT:
1323                 isec->sid = sbsec->mntpoint_sid;
1324                 break;
1325         default:
1326                 /* Default to the fs superblock SID. */
1327                 isec->sid = sbsec->sid;
1328
1329                 if (sbsec->proc && !S_ISLNK(inode->i_mode)) {
1330                         struct proc_inode *proci = PROC_I(inode);
1331                         if (proci->pde) {
1332                                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1333                                 rc = selinux_proc_get_sid(proci->pde,
1334                                                           isec->sclass,
1335                                                           &sid);
1336                                 if (rc)
1337                                         goto out_unlock;
1338                                 isec->sid = sid;
1339                         }
1340                 }
1341                 break;
1342         }
1343
1344         isec->initialized = 1;
1345
1346 out_unlock:
1347         mutex_unlock(&isec->lock);
1348 out:
1349         if (isec->sclass == SECCLASS_FILE)
1350                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1351         return rc;
1352 }
1353
1354 /* Convert a Linux signal to an access vector. */
1355 static inline u32 signal_to_av(int sig)
1356 {
1357         u32 perm = 0;
1358
1359         switch (sig) {
1360         case SIGCHLD:
1361                 /* Commonly granted from child to parent. */
1362                 perm = PROCESS__SIGCHLD;
1363                 break;
1364         case SIGKILL:
1365                 /* Cannot be caught or ignored */
1366                 perm = PROCESS__SIGKILL;
1367                 break;
1368         case SIGSTOP:
1369                 /* Cannot be caught or ignored */
1370                 perm = PROCESS__SIGSTOP;
1371                 break;
1372         default:
1373                 /* All other signals. */
1374                 perm = PROCESS__SIGNAL;
1375                 break;
1376         }
1377
1378         return perm;
1379 }
1380
1381 /*
1382  * Check permission between a pair of credentials
1383  * fork check, ptrace check, etc.
1384  */
1385 static int cred_has_perm(const struct cred *actor,
1386                          const struct cred *target,
1387                          u32 perms)
1388 {
1389         u32 asid = cred_sid(actor), tsid = cred_sid(target);
1390
1391         return avc_has_perm(asid, tsid, SECCLASS_PROCESS, perms, NULL);
1392 }
1393
1394 /*
1395  * Check permission between a pair of tasks, e.g. signal checks,
1396  * fork check, ptrace check, etc.
1397  * tsk1 is the actor and tsk2 is the target
1398  * - this uses the default subjective creds of tsk1
1399  */
1400 static int task_has_perm(const struct task_struct *tsk1,
1401                          const struct task_struct *tsk2,
1402                          u32 perms)
1403 {
1404         const struct task_security_struct *__tsec1, *__tsec2;
1405         u32 sid1, sid2;
1406
1407         rcu_read_lock();
1408         __tsec1 = __task_cred(tsk1)->security;  sid1 = __tsec1->sid;
1409         __tsec2 = __task_cred(tsk2)->security;  sid2 = __tsec2->sid;
1410         rcu_read_unlock();
1411         return avc_has_perm(sid1, sid2, SECCLASS_PROCESS, perms, NULL);
1412 }
1413
1414 /*
1415  * Check permission between current and another task, e.g. signal checks,
1416  * fork check, ptrace check, etc.
1417  * current is the actor and tsk2 is the target
1418  * - this uses current's subjective creds
1419  */
1420 static int current_has_perm(const struct task_struct *tsk,
1421                             u32 perms)
1422 {
1423         u32 sid, tsid;
1424
1425         sid = current_sid();
1426         tsid = task_sid(tsk);
1427         return avc_has_perm(sid, tsid, SECCLASS_PROCESS, perms, NULL);
1428 }
1429
1430 #if CAP_LAST_CAP > 63
1431 #error Fix SELinux to handle capabilities > 63.
1432 #endif
1433
1434 /* Check whether a task is allowed to use a capability. */
1435 static int task_has_capability(struct task_struct *tsk,
1436                                int cap, int audit)
1437 {
1438         struct avc_audit_data ad;
1439         struct av_decision avd;
1440         u16 sclass;
1441         u32 sid = task_sid(tsk);
1442         u32 av = CAP_TO_MASK(cap);
1443         int rc;
1444
1445         AVC_AUDIT_DATA_INIT(&ad, CAP);
1446         ad.tsk = tsk;
1447         ad.u.cap = cap;
1448
1449         switch (CAP_TO_INDEX(cap)) {
1450         case 0:
1451                 sclass = SECCLASS_CAPABILITY;
1452                 break;
1453         case 1:
1454                 sclass = SECCLASS_CAPABILITY2;
1455                 break;
1456         default:
1457                 printk(KERN_ERR
1458                        "SELinux:  out of range capability %d\n", cap);
1459                 BUG();
1460         }
1461
1462         rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);
1463         if (audit == SECURITY_CAP_AUDIT)
1464                 avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
1465         return rc;
1466 }
1467
1468 /* Check whether a task is allowed to use a system operation. */
1469 static int task_has_system(struct task_struct *tsk,
1470                            u32 perms)
1471 {
1472         u32 sid = task_sid(tsk);
1473
1474         return avc_has_perm(sid, SECINITSID_KERNEL,
1475                             SECCLASS_SYSTEM, perms, NULL);
1476 }
1477
1478 /* Check whether a task has a particular permission to an inode.
1479    The 'adp' parameter is optional and allows other audit
1480    data to be passed (e.g. the dentry). */
1481 static int inode_has_perm(const struct cred *cred,
1482                           struct inode *inode,
1483                           u32 perms,
1484                           struct avc_audit_data *adp)
1485 {
1486         struct inode_security_struct *isec;
1487         struct avc_audit_data ad;
1488         u32 sid;
1489
1490         if (unlikely(IS_PRIVATE(inode)))
1491                 return 0;
1492
1493         sid = cred_sid(cred);
1494         isec = inode->i_security;
1495
1496         if (!adp) {
1497                 adp = &ad;
1498                 AVC_AUDIT_DATA_INIT(&ad, FS);
1499                 ad.u.fs.inode = inode;
1500         }
1501
1502         return avc_has_perm(sid, isec->sid, isec->sclass, perms, adp);
1503 }
1504
1505 /* Same as inode_has_perm, but pass explicit audit data containing
1506    the dentry to help the auditing code to more easily generate the
1507    pathname if needed. */
1508 static inline int dentry_has_perm(const struct cred *cred,
1509                                   struct vfsmount *mnt,
1510                                   struct dentry *dentry,
1511                                   u32 av)
1512 {
1513         struct inode *inode = dentry->d_inode;
1514         struct avc_audit_data ad;
1515
1516         AVC_AUDIT_DATA_INIT(&ad, FS);
1517         ad.u.fs.path.mnt = mnt;
1518         ad.u.fs.path.dentry = dentry;
1519         return inode_has_perm(cred, inode, av, &ad);
1520 }
1521
1522 /* Check whether a task can use an open file descriptor to
1523    access an inode in a given way.  Check access to the
1524    descriptor itself, and then use dentry_has_perm to
1525    check a particular permission to the file.
1526    Access to the descriptor is implicitly granted if it
1527    has the same SID as the process.  If av is zero, then
1528    access to the file is not checked, e.g. for cases
1529    where only the descriptor is affected like seek. */
1530 static int file_has_perm(const struct cred *cred,
1531                          struct file *file,
1532                          u32 av)
1533 {
1534         struct file_security_struct *fsec = file->f_security;
1535         struct inode *inode = file->f_path.dentry->d_inode;
1536         struct avc_audit_data ad;
1537         u32 sid = cred_sid(cred);
1538         int rc;
1539
1540         AVC_AUDIT_DATA_INIT(&ad, FS);
1541         ad.u.fs.path = file->f_path;
1542
1543         if (sid != fsec->sid) {
1544                 rc = avc_has_perm(sid, fsec->sid,
1545                                   SECCLASS_FD,
1546                                   FD__USE,
1547                                   &ad);
1548                 if (rc)
1549                         goto out;
1550         }
1551
1552         /* av is zero if only checking access to the descriptor. */
1553         rc = 0;
1554         if (av)
1555                 rc = inode_has_perm(cred, inode, av, &ad);
1556
1557 out:
1558         return rc;
1559 }
1560
1561 /* Check whether a task can create a file. */
1562 static int may_create(struct inode *dir,
1563                       struct dentry *dentry,
1564                       u16 tclass)
1565 {
1566         const struct cred *cred = current_cred();
1567         const struct task_security_struct *tsec = cred->security;
1568         struct inode_security_struct *dsec;
1569         struct superblock_security_struct *sbsec;
1570         u32 sid, newsid;
1571         struct avc_audit_data ad;
1572         int rc;
1573
1574         dsec = dir->i_security;
1575         sbsec = dir->i_sb->s_security;
1576
1577         sid = tsec->sid;
1578         newsid = tsec->create_sid;
1579
1580         AVC_AUDIT_DATA_INIT(&ad, FS);
1581         ad.u.fs.path.dentry = dentry;
1582
1583         rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR,
1584                           DIR__ADD_NAME | DIR__SEARCH,
1585                           &ad);
1586         if (rc)
1587                 return rc;
1588
1589         if (!newsid || sbsec->behavior == SECURITY_FS_USE_MNTPOINT) {
1590                 rc = security_transition_sid(sid, dsec->sid, tclass, &newsid);
1591                 if (rc)
1592                         return rc;
1593         }
1594
1595         rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad);
1596         if (rc)
1597                 return rc;
1598
1599         return avc_has_perm(newsid, sbsec->sid,
1600                             SECCLASS_FILESYSTEM,
1601                             FILESYSTEM__ASSOCIATE, &ad);
1602 }
1603
1604 /* Check whether a task can create a key. */
1605 static int may_create_key(u32 ksid,
1606                           struct task_struct *ctx)
1607 {
1608         u32 sid = task_sid(ctx);
1609
1610         return avc_has_perm(sid, ksid, SECCLASS_KEY, KEY__CREATE, NULL);
1611 }
1612
1613 #define MAY_LINK        0
1614 #define MAY_UNLINK      1
1615 #define MAY_RMDIR       2
1616
1617 /* Check whether a task can link, unlink, or rmdir a file/directory. */
1618 static int may_link(struct inode *dir,
1619                     struct dentry *dentry,
1620                     int kind)
1621
1622 {
1623         struct inode_security_struct *dsec, *isec;
1624         struct avc_audit_data ad;
1625         u32 sid = current_sid();
1626         u32 av;
1627         int rc;
1628
1629         dsec = dir->i_security;
1630         isec = dentry->d_inode->i_security;
1631
1632         AVC_AUDIT_DATA_INIT(&ad, FS);
1633         ad.u.fs.path.dentry = dentry;
1634
1635         av = DIR__SEARCH;
1636         av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME);
1637         rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR, av, &ad);
1638         if (rc)
1639                 return rc;
1640
1641         switch (kind) {
1642         case MAY_LINK:
1643                 av = FILE__LINK;
1644                 break;
1645         case MAY_UNLINK:
1646                 av = FILE__UNLINK;
1647                 break;
1648         case MAY_RMDIR:
1649                 av = DIR__RMDIR;
1650                 break;
1651         default:
1652                 printk(KERN_WARNING "SELinux: %s:  unrecognized kind %d\n",
1653                         __func__, kind);
1654                 return 0;
1655         }
1656
1657         rc = avc_has_perm(sid, isec->sid, isec->sclass, av, &ad);
1658         return rc;
1659 }
1660
1661 static inline int may_rename(struct inode *old_dir,
1662                              struct dentry *old_dentry,
1663                              struct inode *new_dir,
1664                              struct dentry *new_dentry)
1665 {
1666         struct inode_security_struct *old_dsec, *new_dsec, *old_isec, *new_isec;
1667         struct avc_audit_data ad;
1668         u32 sid = current_sid();
1669         u32 av;
1670         int old_is_dir, new_is_dir;
1671         int rc;
1672
1673         old_dsec = old_dir->i_security;
1674         old_isec = old_dentry->d_inode->i_security;
1675         old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
1676         new_dsec = new_dir->i_security;
1677
1678         AVC_AUDIT_DATA_INIT(&ad, FS);
1679
1680         ad.u.fs.path.dentry = old_dentry;
1681         rc = avc_has_perm(sid, old_dsec->sid, SECCLASS_DIR,
1682                           DIR__REMOVE_NAME | DIR__SEARCH, &ad);
1683         if (rc)
1684                 return rc;
1685         rc = avc_has_perm(sid, old_isec->sid,
1686                           old_isec->sclass, FILE__RENAME, &ad);
1687         if (rc)
1688                 return rc;
1689         if (old_is_dir && new_dir != old_dir) {
1690                 rc = avc_has_perm(sid, old_isec->sid,
1691                                   old_isec->sclass, DIR__REPARENT, &ad);
1692                 if (rc)
1693                         return rc;
1694         }
1695
1696         ad.u.fs.path.dentry = new_dentry;
1697         av = DIR__ADD_NAME | DIR__SEARCH;
1698         if (new_dentry->d_inode)
1699                 av |= DIR__REMOVE_NAME;
1700         rc = avc_has_perm(sid, new_dsec->sid, SECCLASS_DIR, av, &ad);
1701         if (rc)
1702                 return rc;
1703         if (new_dentry->d_inode) {
1704                 new_isec = new_dentry->d_inode->i_security;
1705                 new_is_dir = S_ISDIR(new_dentry->d_inode->i_mode);
1706                 rc = avc_has_perm(sid, new_isec->sid,
1707                                   new_isec->sclass,
1708                                   (new_is_dir ? DIR__RMDIR : FILE__UNLINK), &ad);
1709                 if (rc)
1710                         return rc;
1711         }
1712
1713         return 0;
1714 }
1715
1716 /* Check whether a task can perform a filesystem operation. */
1717 static int superblock_has_perm(const struct cred *cred,
1718                                struct super_block *sb,
1719                                u32 perms,
1720                                struct avc_audit_data *ad)
1721 {
1722         struct superblock_security_struct *sbsec;
1723         u32 sid = cred_sid(cred);
1724
1725         sbsec = sb->s_security;
1726         return avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM, perms, ad);
1727 }
1728
1729 /* Convert a Linux mode and permission mask to an access vector. */
1730 static inline u32 file_mask_to_av(int mode, int mask)
1731 {
1732         u32 av = 0;
1733
1734         if ((mode & S_IFMT) != S_IFDIR) {
1735                 if (mask & MAY_EXEC)
1736                         av |= FILE__EXECUTE;
1737                 if (mask & MAY_READ)
1738                         av |= FILE__READ;
1739
1740                 if (mask & MAY_APPEND)
1741                         av |= FILE__APPEND;
1742                 else if (mask & MAY_WRITE)
1743                         av |= FILE__WRITE;
1744
1745         } else {
1746                 if (mask & MAY_EXEC)
1747                         av |= DIR__SEARCH;
1748                 if (mask & MAY_WRITE)
1749                         av |= DIR__WRITE;
1750                 if (mask & MAY_READ)
1751                         av |= DIR__READ;
1752         }
1753
1754         return av;
1755 }
1756
1757 /* Convert a Linux file to an access vector. */
1758 static inline u32 file_to_av(struct file *file)
1759 {
1760         u32 av = 0;
1761
1762         if (file->f_mode & FMODE_READ)
1763                 av |= FILE__READ;
1764         if (file->f_mode & FMODE_WRITE) {
1765                 if (file->f_flags & O_APPEND)
1766                         av |= FILE__APPEND;
1767                 else
1768                         av |= FILE__WRITE;
1769         }
1770         if (!av) {
1771                 /*
1772                  * Special file opened with flags 3 for ioctl-only use.
1773                  */
1774                 av = FILE__IOCTL;
1775         }
1776
1777         return av;
1778 }
1779
1780 /*
1781  * Convert a file to an access vector and include the correct open
1782  * open permission.
1783  */
1784 static inline u32 open_file_to_av(struct file *file)
1785 {
1786         u32 av = file_to_av(file);
1787
1788         if (selinux_policycap_openperm) {
1789                 mode_t mode = file->f_path.dentry->d_inode->i_mode;
1790                 /*
1791                  * lnk files and socks do not really have an 'open'
1792                  */
1793                 if (S_ISREG(mode))
1794                         av |= FILE__OPEN;
1795                 else if (S_ISCHR(mode))
1796                         av |= CHR_FILE__OPEN;
1797                 else if (S_ISBLK(mode))
1798                         av |= BLK_FILE__OPEN;
1799                 else if (S_ISFIFO(mode))
1800                         av |= FIFO_FILE__OPEN;
1801                 else if (S_ISDIR(mode))
1802                         av |= DIR__OPEN;
1803                 else
1804                         printk(KERN_ERR "SELinux: WARNING: inside %s with "
1805                                 "unknown mode:%o\n", __func__, mode);
1806         }
1807         return av;
1808 }
1809
1810 /* Hook functions begin here. */
1811
1812 static int selinux_ptrace_may_access(struct task_struct *child,
1813                                      unsigned int mode)
1814 {
1815         int rc;
1816
1817         rc = secondary_ops->ptrace_may_access(child, mode);
1818         if (rc)
1819                 return rc;
1820
1821         if (mode == PTRACE_MODE_READ) {
1822                 u32 sid = current_sid();
1823                 u32 csid = task_sid(child);
1824                 return avc_has_perm(sid, csid, SECCLASS_FILE, FILE__READ, NULL);
1825         }
1826
1827         return current_has_perm(child, PROCESS__PTRACE);
1828 }
1829
1830 static int selinux_ptrace_traceme(struct task_struct *parent)
1831 {
1832         int rc;
1833
1834         rc = secondary_ops->ptrace_traceme(parent);
1835         if (rc)
1836                 return rc;
1837
1838         return task_has_perm(parent, current, PROCESS__PTRACE);
1839 }
1840
1841 static int selinux_capget(struct task_struct *target, kernel_cap_t *effective,
1842                           kernel_cap_t *inheritable, kernel_cap_t *permitted)
1843 {
1844         int error;
1845
1846         error = current_has_perm(target, PROCESS__GETCAP);
1847         if (error)
1848                 return error;
1849
1850         return secondary_ops->capget(target, effective, inheritable, permitted);
1851 }
1852
1853 static int selinux_capset(struct cred *new, const struct cred *old,
1854                           const kernel_cap_t *effective,
1855                           const kernel_cap_t *inheritable,
1856                           const kernel_cap_t *permitted)
1857 {
1858         int error;
1859
1860         error = secondary_ops->capset(new, old,
1861                                       effective, inheritable, permitted);
1862         if (error)
1863                 return error;
1864
1865         return cred_has_perm(old, new, PROCESS__SETCAP);
1866 }
1867
1868 static int selinux_capable(struct task_struct *tsk, int cap, int audit)
1869 {
1870         int rc;
1871
1872         rc = secondary_ops->capable(tsk, cap, audit);
1873         if (rc)
1874                 return rc;
1875
1876         return task_has_capability(tsk, cap, audit);
1877 }
1878
1879 static int selinux_sysctl_get_sid(ctl_table *table, u16 tclass, u32 *sid)
1880 {
1881         int buflen, rc;
1882         char *buffer, *path, *end;
1883
1884         rc = -ENOMEM;
1885         buffer = (char *)__get_free_page(GFP_KERNEL);
1886         if (!buffer)
1887                 goto out;
1888
1889         buflen = PAGE_SIZE;
1890         end = buffer+buflen;
1891         *--end = '\0';
1892         buflen--;
1893         path = end-1;
1894         *path = '/';
1895         while (table) {
1896                 const char *name = table->procname;
1897                 size_t namelen = strlen(name);
1898                 buflen -= namelen + 1;
1899                 if (buflen < 0)
1900                         goto out_free;
1901                 end -= namelen;
1902                 memcpy(end, name, namelen);
1903                 *--end = '/';
1904                 path = end;
1905                 table = table->parent;
1906         }
1907         buflen -= 4;
1908         if (buflen < 0)
1909                 goto out_free;
1910         end -= 4;
1911         memcpy(end, "/sys", 4);
1912         path = end;
1913         rc = security_genfs_sid("proc", path, tclass, sid);
1914 out_free:
1915         free_page((unsigned long)buffer);
1916 out:
1917         return rc;
1918 }
1919
1920 static int selinux_sysctl(ctl_table *table, int op)
1921 {
1922         int error = 0;
1923         u32 av;
1924         u32 tsid, sid;
1925         int rc;
1926
1927         rc = secondary_ops->sysctl(table, op);
1928         if (rc)
1929                 return rc;
1930
1931         sid = current_sid();
1932
1933         rc = selinux_sysctl_get_sid(table, (op == 0001) ?
1934                                     SECCLASS_DIR : SECCLASS_FILE, &tsid);
1935         if (rc) {
1936                 /* Default to the well-defined sysctl SID. */
1937                 tsid = SECINITSID_SYSCTL;
1938         }
1939
1940         /* The op values are "defined" in sysctl.c, thereby creating
1941          * a bad coupling between this module and sysctl.c */
1942         if (op == 001) {
1943                 error = avc_has_perm(sid, tsid,
1944                                      SECCLASS_DIR, DIR__SEARCH, NULL);
1945         } else {
1946                 av = 0;
1947                 if (op & 004)
1948                         av |= FILE__READ;
1949                 if (op & 002)
1950                         av |= FILE__WRITE;
1951                 if (av)
1952                         error = avc_has_perm(sid, tsid,
1953                                              SECCLASS_FILE, av, NULL);
1954         }
1955
1956         return error;
1957 }
1958
1959 static int selinux_quotactl(int cmds, int type, int id, struct super_block *sb)
1960 {
1961         const struct cred *cred = current_cred();
1962         int rc = 0;
1963
1964         if (!sb)
1965                 return 0;
1966
1967         switch (cmds) {
1968         case Q_SYNC:
1969         case Q_QUOTAON:
1970         case Q_QUOTAOFF:
1971         case Q_SETINFO:
1972         case Q_SETQUOTA:
1973                 rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAMOD, NULL);
1974                 break;
1975         case Q_GETFMT:
1976         case Q_GETINFO:
1977         case Q_GETQUOTA:
1978                 rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAGET, NULL);
1979                 break;
1980         default:
1981                 rc = 0;  /* let the kernel handle invalid cmds */
1982                 break;
1983         }
1984         return rc;
1985 }
1986
1987 static int selinux_quota_on(struct dentry *dentry)
1988 {
1989         const struct cred *cred = current_cred();
1990
1991         return dentry_has_perm(cred, NULL, dentry, FILE__QUOTAON);
1992 }
1993
1994 static int selinux_syslog(int type)
1995 {
1996         int rc;
1997
1998         rc = secondary_ops->syslog(type);
1999         if (rc)
2000                 return rc;
2001
2002         switch (type) {
2003         case 3:         /* Read last kernel messages */
2004         case 10:        /* Return size of the log buffer */
2005                 rc = task_has_system(current, SYSTEM__SYSLOG_READ);
2006                 break;
2007         case 6:         /* Disable logging to console */
2008         case 7:         /* Enable logging to console */
2009         case 8:         /* Set level of messages printed to console */
2010                 rc = task_has_system(current, SYSTEM__SYSLOG_CONSOLE);
2011                 break;
2012         case 0:         /* Close log */
2013         case 1:         /* Open log */
2014         case 2:         /* Read from log */
2015         case 4:         /* Read/clear last kernel messages */
2016         case 5:         /* Clear ring buffer */
2017         default:
2018                 rc = task_has_system(current, SYSTEM__SYSLOG_MOD);
2019                 break;
2020         }
2021         return rc;
2022 }
2023
2024 /*
2025  * Check that a process has enough memory to allocate a new virtual
2026  * mapping. 0 means there is enough memory for the allocation to
2027  * succeed and -ENOMEM implies there is not.
2028  *
2029  * Note that secondary_ops->capable and task_has_perm_noaudit return 0
2030  * if the capability is granted, but __vm_enough_memory requires 1 if
2031  * the capability is granted.
2032  *
2033  * Do not audit the selinux permission check, as this is applied to all
2034  * processes that allocate mappings.
2035  */
2036 static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
2037 {
2038         int rc, cap_sys_admin = 0;
2039
2040         rc = selinux_capable(current, CAP_SYS_ADMIN, SECURITY_CAP_NOAUDIT);
2041         if (rc == 0)
2042                 cap_sys_admin = 1;
2043
2044         return __vm_enough_memory(mm, pages, cap_sys_admin);
2045 }
2046
2047 /* binprm security operations */
2048
2049 static int selinux_bprm_set_creds(struct linux_binprm *bprm)
2050 {
2051         const struct task_security_struct *old_tsec;
2052         struct task_security_struct *new_tsec;
2053         struct inode_security_struct *isec;
2054         struct avc_audit_data ad;
2055         struct inode *inode = bprm->file->f_path.dentry->d_inode;
2056         int rc;
2057
2058         rc = secondary_ops->bprm_set_creds(bprm);
2059         if (rc)
2060                 return rc;
2061
2062         /* SELinux context only depends on initial program or script and not
2063          * the script interpreter */
2064         if (bprm->cred_prepared)
2065                 return 0;
2066
2067         old_tsec = current_security();
2068         new_tsec = bprm->cred->security;
2069         isec = inode->i_security;
2070
2071         /* Default to the current task SID. */
2072         new_tsec->sid = old_tsec->sid;
2073         new_tsec->osid = old_tsec->sid;
2074
2075         /* Reset fs, key, and sock SIDs on execve. */
2076         new_tsec->create_sid = 0;
2077         new_tsec->keycreate_sid = 0;
2078         new_tsec->sockcreate_sid = 0;
2079
2080         if (old_tsec->exec_sid) {
2081                 new_tsec->sid = old_tsec->exec_sid;
2082                 /* Reset exec SID on execve. */
2083                 new_tsec->exec_sid = 0;
2084         } else {
2085                 /* Check for a default transition on this program. */
2086                 rc = security_transition_sid(old_tsec->sid, isec->sid,
2087                                              SECCLASS_PROCESS, &new_tsec->sid);
2088                 if (rc)
2089                         return rc;
2090         }
2091
2092         AVC_AUDIT_DATA_INIT(&ad, FS);
2093         ad.u.fs.path = bprm->file->f_path;
2094
2095         if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)
2096                 new_tsec->sid = old_tsec->sid;
2097
2098         if (new_tsec->sid == old_tsec->sid) {
2099                 rc = avc_has_perm(old_tsec->sid, isec->sid,
2100                                   SECCLASS_FILE, FILE__EXECUTE_NO_TRANS, &ad);
2101                 if (rc)
2102                         return rc;
2103         } else {
2104                 /* Check permissions for the transition. */
2105                 rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
2106                                   SECCLASS_PROCESS, PROCESS__TRANSITION, &ad);
2107                 if (rc)
2108                         return rc;
2109
2110                 rc = avc_has_perm(new_tsec->sid, isec->sid,
2111                                   SECCLASS_FILE, FILE__ENTRYPOINT, &ad);
2112                 if (rc)
2113                         return rc;
2114
2115                 /* Check for shared state */
2116                 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
2117                         rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
2118                                           SECCLASS_PROCESS, PROCESS__SHARE,
2119                                           NULL);
2120                         if (rc)
2121                                 return -EPERM;
2122                 }
2123
2124                 /* Make sure that anyone attempting to ptrace over a task that
2125                  * changes its SID has the appropriate permit */
2126                 if (bprm->unsafe &
2127                     (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
2128                         struct task_struct *tracer;
2129                         struct task_security_struct *sec;
2130                         u32 ptsid = 0;
2131
2132                         rcu_read_lock();
2133                         tracer = tracehook_tracer_task(current);
2134                         if (likely(tracer != NULL)) {
2135                                 sec = __task_cred(tracer)->security;
2136                                 ptsid = sec->sid;
2137                         }
2138                         rcu_read_unlock();
2139
2140                         if (ptsid != 0) {
2141                                 rc = avc_has_perm(ptsid, new_tsec->sid,
2142                                                   SECCLASS_PROCESS,
2143                                                   PROCESS__PTRACE, NULL);
2144                                 if (rc)
2145                                         return -EPERM;
2146                         }
2147                 }
2148
2149                 /* Clear any possibly unsafe personality bits on exec: */
2150                 bprm->per_clear |= PER_CLEAR_ON_SETID;
2151         }
2152
2153         return 0;
2154 }
2155
2156 static int selinux_bprm_check_security(struct linux_binprm *bprm)
2157 {
2158         return secondary_ops->bprm_check_security(bprm);
2159 }
2160
2161 static int selinux_bprm_secureexec(struct linux_binprm *bprm)
2162 {
2163         const struct cred *cred = current_cred();
2164         const struct task_security_struct *tsec = cred->security;
2165         u32 sid, osid;
2166         int atsecure = 0;
2167
2168         sid = tsec->sid;
2169         osid = tsec->osid;
2170
2171         if (osid != sid) {
2172                 /* Enable secure mode for SIDs transitions unless
2173                    the noatsecure permission is granted between
2174                    the two SIDs, i.e. ahp returns 0. */
2175                 atsecure = avc_has_perm(osid, sid,
2176                                         SECCLASS_PROCESS,
2177                                         PROCESS__NOATSECURE, NULL);
2178         }
2179
2180         return (atsecure || secondary_ops->bprm_secureexec(bprm));
2181 }
2182
2183 extern struct vfsmount *selinuxfs_mount;
2184 extern struct dentry *selinux_null;
2185
2186 /* Derived from fs/exec.c:flush_old_files. */
2187 static inline void flush_unauthorized_files(const struct cred *cred,
2188                                             struct files_struct *files)
2189 {
2190         struct avc_audit_data ad;
2191         struct file *file, *devnull = NULL;
2192         struct tty_struct *tty;
2193         struct fdtable *fdt;
2194         long j = -1;
2195         int drop_tty = 0;
2196
2197         tty = get_current_tty();
2198         if (tty) {
2199                 file_list_lock();
2200                 if (!list_empty(&tty->tty_files)) {
2201                         struct inode *inode;
2202
2203                         /* Revalidate access to controlling tty.
2204                            Use inode_has_perm on the tty inode directly rather
2205                            than using file_has_perm, as this particular open
2206                            file may belong to another process and we are only
2207                            interested in the inode-based check here. */
2208                         file = list_first_entry(&tty->tty_files, struct file, f_u.fu_list);
2209                         inode = file->f_path.dentry->d_inode;
2210                         if (inode_has_perm(cred, inode,
2211                                            FILE__READ | FILE__WRITE, NULL)) {
2212                                 drop_tty = 1;
2213                         }
2214                 }
2215                 file_list_unlock();
2216                 tty_kref_put(tty);
2217         }
2218         /* Reset controlling tty. */
2219         if (drop_tty)
2220                 no_tty();
2221
2222         /* Revalidate access to inherited open files. */
2223
2224         AVC_AUDIT_DATA_INIT(&ad, FS);
2225
2226         spin_lock(&files->file_lock);
2227         for (;;) {
2228                 unsigned long set, i;
2229                 int fd;
2230
2231                 j++;
2232                 i = j * __NFDBITS;
2233                 fdt = files_fdtable(files);
2234                 if (i >= fdt->max_fds)
2235                         break;
2236                 set = fdt->open_fds->fds_bits[j];
2237                 if (!set)
2238                         continue;
2239                 spin_unlock(&files->file_lock);
2240                 for ( ; set ; i++, set >>= 1) {
2241                         if (set & 1) {
2242                                 file = fget(i);
2243                                 if (!file)
2244                                         continue;
2245                                 if (file_has_perm(cred,
2246                                                   file,
2247                                                   file_to_av(file))) {
2248                                         sys_close(i);
2249                                         fd = get_unused_fd();
2250                                         if (fd != i) {
2251                                                 if (fd >= 0)
2252                                                         put_unused_fd(fd);
2253                                                 fput(file);
2254                                                 continue;
2255                                         }
2256                                         if (devnull) {
2257                                                 get_file(devnull);
2258                                         } else {
2259                                                 devnull = dentry_open(
2260                                                         dget(selinux_null),
2261                                                         mntget(selinuxfs_mount),
2262                                                         O_RDWR, cred);
2263                                                 if (IS_ERR(devnull)) {
2264                                                         devnull = NULL;
2265                                                         put_unused_fd(fd);
2266                                                         fput(file);
2267                                                         continue;
2268                                                 }
2269                                         }
2270                                         fd_install(fd, devnull);
2271                                 }
2272                                 fput(file);
2273                         }
2274                 }
2275                 spin_lock(&files->file_lock);
2276
2277         }
2278         spin_unlock(&files->file_lock);
2279 }
2280
2281 /*
2282  * Prepare a process for imminent new credential changes due to exec
2283  */
2284 static void selinux_bprm_committing_creds(struct linux_binprm *bprm)
2285 {
2286         struct task_security_struct *new_tsec;
2287         struct rlimit *rlim, *initrlim;
2288         int rc, i;
2289
2290         secondary_ops->bprm_committing_creds(bprm);
2291
2292         new_tsec = bprm->cred->security;
2293         if (new_tsec->sid == new_tsec->osid)
2294                 return;
2295
2296         /* Close files for which the new task SID is not authorized. */
2297         flush_unauthorized_files(bprm->cred, current->files);
2298
2299         /* Always clear parent death signal on SID transitions. */
2300         current->pdeath_signal = 0;
2301
2302         /* Check whether the new SID can inherit resource limits from the old
2303          * SID.  If not, reset all soft limits to the lower of the current
2304          * task's hard limit and the init task's soft limit.
2305          *
2306          * Note that the setting of hard limits (even to lower them) can be
2307          * controlled by the setrlimit check.  The inclusion of the init task's
2308          * soft limit into the computation is to avoid resetting soft limits
2309          * higher than the default soft limit for cases where the default is
2310          * lower than the hard limit, e.g. RLIMIT_CORE or RLIMIT_STACK.
2311          */
2312         rc = avc_has_perm(new_tsec->osid, new_tsec->sid, SECCLASS_PROCESS,
2313                           PROCESS__RLIMITINH, NULL);
2314         if (rc) {
2315                 for (i = 0; i < RLIM_NLIMITS; i++) {
2316                         rlim = current->signal->rlim + i;
2317                         initrlim = init_task.signal->rlim + i;
2318                         rlim->rlim_cur = min(rlim->rlim_max, initrlim->rlim_cur);
2319                 }
2320                 update_rlimit_cpu(rlim->rlim_cur);
2321         }
2322 }
2323
2324 /*
2325  * Clean up the process immediately after the installation of new credentials
2326  * due to exec
2327  */
2328 static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
2329 {
2330         const struct task_security_struct *tsec = current_security();
2331         struct itimerval itimer;
2332         struct sighand_struct *psig;
2333         u32 osid, sid;
2334         int rc, i;
2335         unsigned long flags;
2336
2337         secondary_ops->bprm_committed_creds(bprm);
2338
2339         osid = tsec->osid;
2340         sid = tsec->sid;
2341
2342         if (sid == osid)
2343                 return;
2344
2345         /* Check whether the new SID can inherit signal state from the old SID.
2346          * If not, clear itimers to avoid subsequent signal generation and
2347          * flush and unblock signals.
2348          *
2349          * This must occur _after_ the task SID has been updated so that any
2350          * kill done after the flush will be checked against the new SID.
2351          */
2352         rc = avc_has_perm(osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL);
2353         if (rc) {
2354                 memset(&itimer, 0, sizeof itimer);
2355                 for (i = 0; i < 3; i++)
2356                         do_setitimer(i, &itimer, NULL);
2357                 flush_signals(current);
2358                 spin_lock_irq(&current->sighand->siglock);
2359                 flush_signal_handlers(current, 1);
2360                 sigemptyset(&current->blocked);
2361                 recalc_sigpending();
2362                 spin_unlock_irq(&current->sighand->siglock);
2363         }
2364
2365         /* Wake up the parent if it is waiting so that it can recheck
2366          * wait permission to the new task SID. */
2367         read_lock_irq(&tasklist_lock);
2368         psig = current->parent->sighand;
2369         spin_lock_irqsave(&psig->siglock, flags);
2370         wake_up_interruptible(&current->parent->signal->wait_chldexit);
2371         spin_unlock_irqrestore(&psig->siglock, flags);
2372         read_unlock_irq(&tasklist_lock);
2373 }
2374
2375 /* superblock security operations */
2376
2377 static int selinux_sb_alloc_security(struct super_block *sb)
2378 {
2379         return superblock_alloc_security(sb);
2380 }
2381
2382 static void selinux_sb_free_security(struct super_block *sb)
2383 {
2384         superblock_free_security(sb);
2385 }
2386
2387 static inline int match_prefix(char *prefix, int plen, char *option, int olen)
2388 {
2389         if (plen > olen)
2390                 return 0;
2391
2392         return !memcmp(prefix, option, plen);
2393 }
2394
2395 static inline int selinux_option(char *option, int len)
2396 {
2397         return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
2398                 match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
2399                 match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
2400                 match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len));
2401 }
2402
2403 static inline void take_option(char **to, char *from, int *first, int len)
2404 {
2405         if (!*first) {
2406                 **to = ',';
2407                 *to += 1;
2408         } else
2409                 *first = 0;
2410         memcpy(*to, from, len);
2411         *to += len;
2412 }
2413
2414 static inline void take_selinux_option(char **to, char *from, int *first,
2415                                        int len)
2416 {
2417         int current_size = 0;
2418
2419         if (!*first) {
2420                 **to = '|';
2421                 *to += 1;
2422         } else
2423                 *first = 0;
2424
2425         while (current_size < len) {
2426                 if (*from != '"') {
2427                         **to = *from;
2428                         *to += 1;
2429                 }
2430                 from += 1;
2431                 current_size += 1;
2432         }
2433 }
2434
2435 static int selinux_sb_copy_data(char *orig, char *copy)
2436 {
2437         int fnosec, fsec, rc = 0;
2438         char *in_save, *in_curr, *in_end;
2439         char *sec_curr, *nosec_save, *nosec;
2440         int open_quote = 0;
2441
2442         in_curr = orig;
2443         sec_curr = copy;
2444
2445         nosec = (char *)get_zeroed_page(GFP_KERNEL);
2446         if (!nosec) {
2447                 rc = -ENOMEM;
2448                 goto out;
2449         }
2450
2451         nosec_save = nosec;
2452         fnosec = fsec = 1;
2453         in_save = in_end = orig;
2454
2455         do {
2456                 if (*in_end == '"')
2457                         open_quote = !open_quote;
2458                 if ((*in_end == ',' && open_quote == 0) ||
2459                                 *in_end == '\0') {
2460                         int len = in_end - in_curr;
2461
2462                         if (selinux_option(in_curr, len))
2463                                 take_selinux_option(&sec_curr, in_curr, &fsec, len);
2464                         else
2465                                 take_option(&nosec, in_curr, &fnosec, len);
2466
2467                         in_curr = in_end + 1;
2468                 }
2469         } while (*in_end++);
2470
2471         strcpy(in_save, nosec_save);
2472         free_page((unsigned long)nosec_save);
2473 out:
2474         return rc;
2475 }
2476
2477 static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
2478 {
2479         const struct cred *cred = current_cred();
2480         struct avc_audit_data ad;
2481         int rc;
2482
2483         rc = superblock_doinit(sb, data);
2484         if (rc)
2485                 return rc;
2486
2487         /* Allow all mounts performed by the kernel */
2488         if (flags & MS_KERNMOUNT)
2489                 return 0;
2490
2491         AVC_AUDIT_DATA_INIT(&ad, FS);
2492         ad.u.fs.path.dentry = sb->s_root;
2493         return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad);
2494 }
2495
2496 static int selinux_sb_statfs(struct dentry *dentry)
2497 {
2498         const struct cred *cred = current_cred();
2499         struct avc_audit_data ad;
2500
2501         AVC_AUDIT_DATA_INIT(&ad, FS);
2502         ad.u.fs.path.dentry = dentry->d_sb->s_root;
2503         return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad);
2504 }
2505
2506 static int selinux_mount(char *dev_name,
2507                          struct path *path,
2508                          char *type,
2509                          unsigned long flags,
2510                          void *data)
2511 {
2512         const struct cred *cred = current_cred();
2513         int rc;
2514
2515         rc = secondary_ops->sb_mount(dev_name, path, type, flags, data);
2516         if (rc)
2517                 return rc;
2518
2519         if (flags & MS_REMOUNT)
2520                 return superblock_has_perm(cred, path->mnt->mnt_sb,
2521                                            FILESYSTEM__REMOUNT, NULL);
2522         else
2523                 return dentry_has_perm(cred, path->mnt, path->dentry,
2524                                        FILE__MOUNTON);
2525 }
2526
2527 static int selinux_umount(struct vfsmount *mnt, int flags)
2528 {
2529         const struct cred *cred = current_cred();
2530         int rc;
2531
2532         rc = secondary_ops->sb_umount(mnt, flags);
2533         if (rc)
2534                 return rc;
2535
2536         return superblock_has_perm(cred, mnt->mnt_sb,
2537                                    FILESYSTEM__UNMOUNT, NULL);
2538 }
2539
2540 /* inode security operations */
2541
2542 static int selinux_inode_alloc_security(struct inode *inode)
2543 {
2544         return inode_alloc_security(inode);
2545 }
2546
2547 static void selinux_inode_free_security(struct inode *inode)
2548 {
2549         inode_free_security(inode);
2550 }
2551
2552 static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
2553                                        char **name, void **value,
2554                                        size_t *len)
2555 {
2556         const struct cred *cred = current_cred();
2557         const struct task_security_struct *tsec = cred->security;
2558         struct inode_security_struct *dsec;
2559         struct superblock_security_struct *sbsec;
2560         u32 sid, newsid, clen;
2561         int rc;
2562         char *namep = NULL, *context;
2563
2564         dsec = dir->i_security;
2565         sbsec = dir->i_sb->s_security;
2566
2567         sid = tsec->sid;
2568         newsid = tsec->create_sid;
2569
2570         if (!newsid || sbsec->behavior == SECURITY_FS_USE_MNTPOINT) {
2571                 rc = security_transition_sid(sid, dsec->sid,
2572                                              inode_mode_to_security_class(inode->i_mode),
2573                                              &newsid);
2574                 if (rc) {
2575                         printk(KERN_WARNING "%s:  "
2576                                "security_transition_sid failed, rc=%d (dev=%s "
2577                                "ino=%ld)\n",
2578                                __func__,
2579                                -rc, inode->i_sb->s_id, inode->i_ino);
2580                         return rc;
2581                 }
2582         }
2583
2584         /* Possibly defer initialization to selinux_complete_init. */
2585         if (sbsec->initialized) {
2586                 struct inode_security_struct *isec = inode->i_security;
2587                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
2588                 isec->sid = newsid;
2589                 isec->initialized = 1;
2590         }
2591
2592         if (!ss_initialized || sbsec->behavior == SECURITY_FS_USE_MNTPOINT)
2593                 return -EOPNOTSUPP;
2594
2595         if (name) {
2596                 namep = kstrdup(XATTR_SELINUX_SUFFIX, GFP_NOFS);
2597                 if (!namep)
2598                         return -ENOMEM;
2599                 *name = namep;
2600         }
2601
2602         if (value && len) {
2603                 rc = security_sid_to_context_force(newsid, &context, &clen);
2604                 if (rc) {
2605                         kfree(namep);
2606                         return rc;
2607                 }
2608                 *value = context;
2609                 *len = clen;
2610         }
2611
2612         return 0;
2613 }
2614
2615 static int selinux_inode_create(struct inode *dir, struct dentry *dentry, int mask)
2616 {
2617         return may_create(dir, dentry, SECCLASS_FILE);
2618 }
2619
2620 static int selinux_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
2621 {
2622         int rc;
2623
2624         rc = secondary_ops->inode_link(old_dentry, dir, new_dentry);
2625         if (rc)
2626                 return rc;
2627         return may_link(dir, old_dentry, MAY_LINK);
2628 }
2629
2630 static int selinux_inode_unlink(struct inode *dir, struct dentry *dentry)
2631 {
2632         int rc;
2633
2634         rc = secondary_ops->inode_unlink(dir, dentry);
2635         if (rc)
2636                 return rc;
2637         return may_link(dir, dentry, MAY_UNLINK);
2638 }
2639
2640 static int selinux_inode_symlink(struct inode *dir, struct dentry *dentry, const char *name)
2641 {
2642         return may_create(dir, dentry, SECCLASS_LNK_FILE);
2643 }
2644
2645 static int selinux_inode_mkdir(struct inode *dir, struct dentry *dentry, int mask)
2646 {
2647         return may_create(dir, dentry, SECCLASS_DIR);
2648 }
2649
2650 static int selinux_inode_rmdir(struct inode *dir, struct dentry *dentry)
2651 {
2652         return may_link(dir, dentry, MAY_RMDIR);
2653 }
2654
2655 static int selinux_inode_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
2656 {
2657         int rc;
2658
2659         rc = secondary_ops->inode_mknod(dir, dentry, mode, dev);
2660         if (rc)
2661                 return rc;
2662
2663         return may_create(dir, dentry, inode_mode_to_security_class(mode));
2664 }
2665
2666 static int selinux_inode_rename(struct inode *old_inode, struct dentry *old_dentry,
2667                                 struct inode *new_inode, struct dentry *new_dentry)
2668 {
2669         return may_rename(old_inode, old_dentry, new_inode, new_dentry);
2670 }
2671
2672 static int selinux_inode_readlink(struct dentry *dentry)
2673 {
2674         const struct cred *cred = current_cred();
2675
2676         return dentry_has_perm(cred, NULL, dentry, FILE__READ);
2677 }
2678
2679 static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *nameidata)
2680 {
2681         const struct cred *cred = current_cred();
2682         int rc;
2683
2684         rc = secondary_ops->inode_follow_link(dentry, nameidata);
2685         if (rc)
2686                 return rc;
2687         return dentry_has_perm(cred, NULL, dentry, FILE__READ);
2688 }
2689
2690 static int selinux_inode_permission(struct inode *inode, int mask)
2691 {
2692         const struct cred *cred = current_cred();
2693         int rc;
2694
2695         rc = secondary_ops->inode_permission(inode, mask);
2696         if (rc)
2697                 return rc;
2698
2699         if (!mask) {
2700                 /* No permission to check.  Existence test. */
2701                 return 0;
2702         }
2703
2704         return inode_has_perm(cred, inode,
2705                               file_mask_to_av(inode->i_mode, mask), NULL);
2706 }
2707
2708 static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
2709 {
2710         const struct cred *cred = current_cred();
2711         int rc;
2712
2713         rc = secondary_ops->inode_setattr(dentry, iattr);
2714         if (rc)
2715                 return rc;
2716
2717         if (iattr->ia_valid & ATTR_FORCE)
2718                 return 0;
2719
2720         if (iattr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID |
2721                                ATTR_ATIME_SET | ATTR_MTIME_SET))
2722                 return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR);
2723
2724         return dentry_has_perm(cred, NULL, dentry, FILE__WRITE);
2725 }
2726
2727 static int selinux_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
2728 {
2729         const struct cred *cred = current_cred();
2730
2731         return dentry_has_perm(cred, mnt, dentry, FILE__GETATTR);
2732 }
2733
2734 static int selinux_inode_setotherxattr(struct dentry *dentry, const char *name)
2735 {
2736         const struct cred *cred = current_cred();
2737
2738         if (!strncmp(name, XATTR_SECURITY_PREFIX,
2739                      sizeof XATTR_SECURITY_PREFIX - 1)) {
2740                 if (!strcmp(name, XATTR_NAME_CAPS)) {
2741                         if (!capable(CAP_SETFCAP))
2742                                 return -EPERM;
2743                 } else if (!capable(CAP_SYS_ADMIN)) {
2744                         /* A different attribute in the security namespace.
2745                            Restrict to administrator. */
2746                         return -EPERM;
2747                 }
2748         }
2749
2750         /* Not an attribute we recognize, so just check the
2751            ordinary setattr permission. */
2752         return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR);
2753 }
2754
2755 static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
2756                                   const void *value, size_t size, int flags)
2757 {
2758         struct inode *inode = dentry->d_inode;
2759         struct inode_security_struct *isec = inode->i_security;
2760         struct superblock_security_struct *sbsec;
2761         struct avc_audit_data ad;
2762         u32 newsid, sid = current_sid();
2763         int rc = 0;
2764
2765         if (strcmp(name, XATTR_NAME_SELINUX))
2766                 return selinux_inode_setotherxattr(dentry, name);
2767
2768         sbsec = inode->i_sb->s_security;
2769         if (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)
2770                 return -EOPNOTSUPP;
2771
2772         if (!is_owner_or_cap(inode))
2773                 return -EPERM;
2774
2775         AVC_AUDIT_DATA_INIT(&ad, FS);
2776         ad.u.fs.path.dentry = dentry;
2777
2778         rc = avc_has_perm(sid, isec->sid, isec->sclass,
2779                           FILE__RELABELFROM, &ad);
2780         if (rc)
2781                 return rc;
2782
2783         rc = security_context_to_sid(value, size, &newsid);
2784         if (rc == -EINVAL) {
2785                 if (!capable(CAP_MAC_ADMIN))
2786                         return rc;
2787                 rc = security_context_to_sid_force(value, size, &newsid);
2788         }
2789         if (rc)
2790                 return rc;
2791
2792         rc = avc_has_perm(sid, newsid, isec->sclass,
2793                           FILE__RELABELTO, &ad);
2794         if (rc)
2795                 return rc;
2796
2797         rc = security_validate_transition(isec->sid, newsid, sid,
2798                                           isec->sclass);
2799         if (rc)
2800                 return rc;
2801
2802         return avc_has_perm(newsid,
2803                             sbsec->sid,
2804                             SECCLASS_FILESYSTEM,
2805                             FILESYSTEM__ASSOCIATE,
2806                             &ad);
2807 }
2808
2809 static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name,
2810                                         const void *value, size_t size,
2811                                         int flags)
2812 {
2813         struct inode *inode = dentry->d_inode;
2814         struct inode_security_struct *isec = inode->i_security;
2815         u32 newsid;
2816         int rc;
2817
2818         if (strcmp(name, XATTR_NAME_SELINUX)) {
2819                 /* Not an attribute we recognize, so nothing to do. */
2820                 return;
2821         }
2822
2823         rc = security_context_to_sid_force(value, size, &newsid);
2824         if (rc) {
2825                 printk(KERN_ERR "SELinux:  unable to map context to SID"
2826                        "for (%s, %lu), rc=%d\n",
2827                        inode->i_sb->s_id, inode->i_ino, -rc);
2828                 return;
2829         }
2830
2831         isec->sid = newsid;
2832         return;
2833 }
2834
2835 static int selinux_inode_getxattr(struct dentry *dentry, const char *name)
2836 {
2837         const struct cred *cred = current_cred();
2838
2839         return dentry_has_perm(cred, NULL, dentry, FILE__GETATTR);
2840 }
2841
2842 static int selinux_inode_listxattr(struct dentry *dentry)
2843 {
2844         const struct cred *cred = current_cred();
2845
2846         return dentry_has_perm(cred, NULL, dentry, FILE__GETATTR);
2847 }
2848
2849 static int selinux_inode_removexattr(struct dentry *dentry, const char *name)
2850 {
2851         if (strcmp(name, XATTR_NAME_SELINUX))
2852                 return selinux_inode_setotherxattr(dentry, name);
2853
2854         /* No one is allowed to remove a SELinux security label.
2855            You can change the label, but all data must be labeled. */
2856         return -EACCES;
2857 }
2858
2859 /*
2860  * Copy the inode security context value to the user.
2861  *
2862  * Permission check is handled by selinux_inode_getxattr hook.
2863  */
2864 static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc)
2865 {
2866         u32 size;
2867         int error;
2868         char *context = NULL;
2869         struct inode_security_struct *isec = inode->i_security;
2870
2871         if (strcmp(name, XATTR_SELINUX_SUFFIX))
2872                 return -EOPNOTSUPP;
2873
2874         /*
2875          * If the caller has CAP_MAC_ADMIN, then get the raw context
2876          * value even if it is not defined by current policy; otherwise,
2877          * use the in-core value under current policy.
2878          * Use the non-auditing forms of the permission checks since
2879          * getxattr may be called by unprivileged processes commonly
2880          * and lack of permission just means that we fall back to the
2881          * in-core context value, not a denial.
2882          */
2883         error = selinux_capable(current, CAP_MAC_ADMIN, SECURITY_CAP_NOAUDIT);
2884         if (!error)
2885                 error = security_sid_to_context_force(isec->sid, &context,
2886                                                       &size);
2887         else
2888                 error = security_sid_to_context(isec->sid, &context, &size);
2889         if (error)
2890                 return error;
2891         error = size;
2892         if (alloc) {
2893                 *buffer = context;
2894                 goto out_nofree;
2895         }
2896         kfree(context);
2897 out_nofree:
2898         return error;
2899 }
2900
2901 static int selinux_inode_setsecurity(struct inode *inode, const char *name,
2902                                      const void *value, size_t size, int flags)
2903 {
2904         struct inode_security_struct *isec = inode->i_security;
2905         u32 newsid;
2906         int rc;
2907
2908         if (strcmp(name, XATTR_SELINUX_SUFFIX))
2909                 return -EOPNOTSUPP;
2910
2911         if (!value || !size)
2912                 return -EACCES;
2913
2914         rc = security_context_to_sid((void *)value, size, &newsid);
2915         if (rc)
2916                 return rc;
2917
2918         isec->sid = newsid;
2919         return 0;
2920 }
2921
2922 static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)
2923 {
2924         const int len = sizeof(XATTR_NAME_SELINUX);
2925         if (buffer && len <= buffer_size)
2926                 memcpy(buffer, XATTR_NAME_SELINUX, len);
2927         return len;
2928 }
2929
2930 static int selinux_inode_need_killpriv(struct dentry *dentry)
2931 {
2932         return secondary_ops->inode_need_killpriv(dentry);
2933 }
2934
2935 static int selinux_inode_killpriv(struct dentry *dentry)
2936 {
2937         return secondary_ops->inode_killpriv(dentry);
2938 }
2939
2940 static void selinux_inode_getsecid(const struct inode *inode, u32 *secid)
2941 {
2942         struct inode_security_struct *isec = inode->i_security;
2943         *secid = isec->sid;
2944 }
2945
2946 /* file security operations */
2947
2948 static int selinux_revalidate_file_permission(struct file *file, int mask)
2949 {
2950         const struct cred *cred = current_cred();
2951         int rc;
2952         struct inode *inode = file->f_path.dentry->d_inode;
2953
2954         if (!mask) {
2955                 /* No permission to check.  Existence test. */
2956                 return 0;
2957         }
2958
2959         /* file_mask_to_av won't add FILE__WRITE if MAY_APPEND is set */
2960         if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE))
2961                 mask |= MAY_APPEND;
2962
2963         rc = file_has_perm(cred, file,
2964                            file_mask_to_av(inode->i_mode, mask));
2965         if (rc)
2966                 return rc;
2967
2968         return selinux_netlbl_inode_permission(inode, mask);
2969 }
2970
2971 static int selinux_file_permission(struct file *file, int mask)
2972 {
2973         struct inode *inode = file->f_path.dentry->d_inode;
2974         struct file_security_struct *fsec = file->f_security;
2975         struct inode_security_struct *isec = inode->i_security;
2976         u32 sid = current_sid();
2977
2978         if (!mask) {
2979                 /* No permission to check.  Existence test. */
2980                 return 0;
2981         }
2982
2983         if (sid == fsec->sid && fsec->isid == isec->sid
2984             && fsec->pseqno == avc_policy_seqno())
2985                 return selinux_netlbl_inode_permission(inode, mask);
2986
2987         return selinux_revalidate_file_permission(file, mask);
2988 }
2989
2990 static int selinux_file_alloc_security(struct file *file)
2991 {
2992         return file_alloc_security(file);
2993 }
2994
2995 static void selinux_file_free_security(struct file *file)
2996 {
2997         file_free_security(file);
2998 }
2999
3000 static int selinux_file_ioctl(struct file *file, unsigned int cmd,
3001                               unsigned long arg)
3002 {
3003         const struct cred *cred = current_cred();
3004         u32 av = 0;
3005
3006         if (_IOC_DIR(cmd) & _IOC_WRITE)
3007                 av |= FILE__WRITE;
3008         if (_IOC_DIR(cmd) & _IOC_READ)
3009                 av |= FILE__READ;
3010         if (!av)
3011                 av = FILE__IOCTL;
3012
3013         return file_has_perm(cred, file, av);
3014 }
3015
3016 static int file_map_prot_check(struct file *file, unsigned long prot, int shared)
3017 {
3018         const struct cred *cred = current_cred();
3019         int rc = 0;
3020
3021 #ifndef CONFIG_PPC32
3022         if ((prot & PROT_EXEC) && (!file || (!shared && (prot & PROT_WRITE)))) {
3023                 /*
3024                  * We are making executable an anonymous mapping or a
3025                  * private file mapping that will also be writable.
3026                  * This has an additional check.
3027                  */
3028                 rc = cred_has_perm(cred, cred, PROCESS__EXECMEM);
3029                 if (rc)
3030                         goto error;
3031         }
3032 #endif
3033
3034         if (file) {
3035                 /* read access is always possible with a mapping */
3036                 u32 av = FILE__READ;
3037
3038                 /* write access only matters if the mapping is shared */
3039                 if (shared && (prot & PROT_WRITE))
3040                         av |= FILE__WRITE;
3041
3042                 if (prot & PROT_EXEC)
3043                         av |= FILE__EXECUTE;
3044
3045                 return file_has_perm(cred, file, av);
3046         }
3047
3048 error:
3049         return rc;
3050 }
3051
3052 static int selinux_file_mmap(struct file *file, unsigned long reqprot,
3053                              unsigned long prot, unsigned long flags,
3054                              unsigned long addr, unsigned long addr_only)
3055 {
3056         int rc = 0;
3057         u32 sid = current_sid();
3058
3059         if (addr < mmap_min_addr)
3060                 rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
3061                                   MEMPROTECT__MMAP_ZERO, NULL);
3062         if (rc || addr_only)
3063                 return rc;
3064
3065         if (selinux_checkreqprot)
3066                 prot = reqprot;
3067
3068         return file_map_prot_check(file, prot,
3069                                    (flags & MAP_TYPE) == MAP_SHARED);
3070 }
3071
3072 static int selinux_file_mprotect(struct vm_area_struct *vma,
3073                                  unsigned long reqprot,
3074                                  unsigned long prot)
3075 {
3076         const struct cred *cred = current_cred();
3077         int rc;
3078
3079         rc = secondary_ops->file_mprotect(vma, reqprot, prot);
3080         if (rc)
3081                 return rc;
3082
3083         if (selinux_checkreqprot)
3084                 prot = reqprot;
3085
3086 #ifndef CONFIG_PPC32
3087         if ((prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
3088                 rc = 0;
3089                 if (vma->vm_start >= vma->vm_mm->start_brk &&
3090                     vma->vm_end <= vma->vm_mm->brk) {
3091                         rc = cred_has_perm(cred, cred, PROCESS__EXECHEAP);
3092                 } else if (!vma->vm_file &&
3093                            vma->vm_start <= vma->vm_mm->start_stack &&
3094                            vma->vm_end >= vma->vm_mm->start_stack) {
3095                         rc = current_has_perm(current, PROCESS__EXECSTACK);
3096                 } else if (vma->vm_file && vma->anon_vma) {
3097                         /*
3098                          * We are making executable a file mapping that has
3099                          * had some COW done. Since pages might have been
3100                          * written, check ability to execute the possibly
3101                          * modified content.  This typically should only
3102                          * occur for text relocations.
3103                          */
3104                         rc = file_has_perm(cred, vma->vm_file, FILE__EXECMOD);
3105                 }
3106                 if (rc)
3107                         return rc;
3108         }
3109 #endif
3110
3111         return file_map_prot_check(vma->vm_file, prot, vma->vm_flags&VM_SHARED);
3112 }
3113
3114 static int selinux_file_lock(struct file *file, unsigned int cmd)
3115 {
3116         const struct cred *cred = current_cred();
3117
3118         return file_has_perm(cred, file, FILE__LOCK);
3119 }
3120
3121 static int selinux_file_fcntl(struct file *file, unsigned int cmd,
3122                               unsigned long arg)
3123 {
3124         const struct cred *cred = current_cred();
3125         int err = 0;
3126
3127         switch (cmd) {
3128         case F_SETFL:
3129                 if (!file->f_path.dentry || !file->f_path.dentry->d_inode) {
3130                         err = -EINVAL;
3131                         break;
3132                 }
3133
3134                 if ((file->f_flags & O_APPEND) && !(arg & O_APPEND)) {
3135                         err = file_has_perm(cred, file, FILE__WRITE);
3136                         break;
3137                 }
3138                 /* fall through */
3139         case F_SETOWN:
3140         case F_SETSIG:
3141         case F_GETFL:
3142         case F_GETOWN:
3143         case F_GETSIG:
3144                 /* Just check FD__USE permission */
3145                 err = file_has_perm(cred, file, 0);
3146                 break;
3147         case F_GETLK:
3148         case F_SETLK:
3149         case F_SETLKW:
3150 #if BITS_PER_LONG == 32
3151         case F_GETLK64:
3152         case F_SETLK64:
3153         case F_SETLKW64:
3154 #endif
3155                 if (!file->f_path.dentry || !file->f_path.dentry->d_inode) {
3156                         err = -EINVAL;
3157                         break;
3158                 }
3159                 err = file_has_perm(cred, file, FILE__LOCK);
3160                 break;
3161         }
3162
3163         return err;
3164 }
3165
3166 static int selinux_file_set_fowner(struct file *file)
3167 {
3168         struct file_security_struct *fsec;
3169
3170         fsec = file->f_security;
3171         fsec->fown_sid = current_sid();
3172
3173         return 0;
3174 }
3175
3176 static int selinux_file_send_sigiotask(struct task_struct *tsk,
3177                                        struct fown_struct *fown, int signum)
3178 {
3179         struct file *file;
3180         u32 sid = current_sid();
3181         u32 perm;
3182         struct file_security_struct *fsec;
3183
3184         /* struct fown_struct is never outside the context of a struct file */
3185         file = container_of(fown, struct file, f_owner);
3186
3187         fsec = file->f_security;
3188
3189         if (!signum)
3190                 perm = signal_to_av(SIGIO); /* as per send_sigio_to_task */
3191         else
3192                 perm = signal_to_av(signum);
3193
3194         return avc_has_perm(fsec->fown_sid, sid,
3195                             SECCLASS_PROCESS, perm, NULL);
3196 }
3197
3198 static int selinux_file_receive(struct file *file)
3199 {
3200         const struct cred *cred = current_cred();
3201
3202         return file_has_perm(cred, file, file_to_av(file));
3203 }
3204
3205 static int selinux_dentry_open(struct file *file, const struct cred *cred)
3206 {
3207         struct file_security_struct *fsec;
3208         struct inode *inode;
3209         struct inode_security_struct *isec;
3210
3211         inode = file->f_path.dentry->d_inode;
3212         fsec = file->f_security;
3213         isec = inode->i_security;
3214         /*
3215          * Save inode label and policy sequence number
3216          * at open-time so that selinux_file_permission
3217          * can determine whether revalidation is necessary.
3218          * Task label is already saved in the file security
3219          * struct as its SID.
3220          */
3221         fsec->isid = isec->sid;
3222         fsec->pseqno = avc_policy_seqno();
3223         /*
3224          * Since the inode label or policy seqno may have changed
3225          * between the selinux_inode_permission check and the saving
3226          * of state above, recheck that access is still permitted.
3227          * Otherwise, access might never be revalidated against the
3228          * new inode label or new policy.
3229          * This check is not redundant - do not remove.
3230          */
3231         return inode_has_perm(cred, inode, open_file_to_av(file), NULL);
3232 }
3233
3234 /* task security operations */
3235
3236 static int selinux_task_create(unsigned long clone_flags)
3237 {
3238         int rc;
3239
3240         rc = secondary_ops->task_create(clone_flags);
3241         if (rc)
3242                 return rc;
3243
3244         return current_has_perm(current, PROCESS__FORK);
3245 }
3246
3247 /*
3248  * detach and free the LSM part of a set of credentials
3249  */
3250 static void selinux_cred_free(struct cred *cred)
3251 {
3252         struct task_security_struct *tsec = cred->security;
3253         cred->security = NULL;
3254         kfree(tsec);
3255 }
3256
3257 /*
3258  * prepare a new set of credentials for modification
3259  */
3260 static int selinux_cred_prepare(struct cred *new, const struct cred *old,
3261                                 gfp_t gfp)
3262 {
3263         const struct task_security_struct *old_tsec;
3264         struct task_security_struct *tsec;
3265
3266         old_tsec = old->security;
3267
3268         tsec = kmemdup(old_tsec, sizeof(struct task_security_struct), gfp);
3269         if (!tsec)
3270                 return -ENOMEM;
3271
3272         new->security = tsec;
3273         return 0;
3274 }
3275
3276 /*
3277  * commit new credentials
3278  */
3279 static void selinux_cred_commit(struct cred *new, const struct cred *old)
3280 {
3281         secondary_ops->cred_commit(new, old);
3282 }
3283
3284 /*
3285  * set the security data for a kernel service
3286  * - all the creation contexts are set to unlabelled
3287  */
3288 static int selinux_kernel_act_as(struct cred *new, u32 secid)
3289 {
3290         struct task_security_struct *tsec = new->security;
3291         u32 sid = current_sid();
3292         int ret;
3293
3294         ret = avc_has_perm(sid, secid,
3295                            SECCLASS_KERNEL_SERVICE,
3296                            KERNEL_SERVICE__USE_AS_OVERRIDE,
3297                            NULL);
3298         if (ret == 0) {
3299                 tsec->sid = secid;
3300                 tsec->create_sid = 0;
3301                 tsec->keycreate_sid = 0;
3302                 tsec->sockcreate_sid = 0;
3303         }
3304         return ret;
3305 }
3306
3307 /*
3308  * set the file creation context in a security record to the same as the
3309  * objective context of the specified inode
3310  */