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, 2009 Hewlett-Packard Development Company, L.P.
  17  *      Paul Moore <paul@paul-moore.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/kd.h>
  28 #include <linux/kernel.h>
  29 #include <linux/tracehook.h>
  30 #include <linux/errno.h>
  31 #include <linux/ext2_fs.h>
  32 #include <linux/sched.h>
  33 #include <linux/security.h>
  34 #include <linux/xattr.h>
  35 #include <linux/capability.h>
  36 #include <linux/unistd.h>
  37 #include <linux/mm.h>
  38 #include <linux/mman.h>
  39 #include <linux/slab.h>
  40 #include <linux/pagemap.h>
  41 #include <linux/proc_fs.h>
  42 #include <linux/swap.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/syscalls.h>
  45 #include <linux/dcache.h>
  46 #include <linux/file.h>
  47 #include <linux/fdtable.h>
  48 #include <linux/namei.h>
  49 #include <linux/mount.h>
  50 #include <linux/netfilter_ipv4.h>
  51 #include <linux/netfilter_ipv6.h>
  52 #include <linux/tty.h>
  53 #include <net/icmp.h>
  54 #include <net/ip.h>             /* for local_port_range[] */
  55 #include <net/tcp.h>            /* struct or_callable used in sock_rcv_skb */
  56 #include <net/net_namespace.h>
  57 #include <net/netlabel.h>
  58 #include <linux/uaccess.h>
  59 #include <asm/ioctls.h>
  60 #include <linux/atomic.h>
  61 #include <linux/bitops.h>
  62 #include <linux/interrupt.h>
  63 #include <linux/netdevice.h>    /* for network interface checks */
  64 #include <linux/netlink.h>
  65 #include <linux/tcp.h>
  66 #include <linux/udp.h>
  67 #include <linux/dccp.h>
  68 #include <linux/quota.h>
  69 #include <linux/un.h>           /* for Unix socket types */
  70 #include <net/af_unix.h>        /* for Unix socket types */
  71 #include <linux/parser.h>
  72 #include <linux/nfs_mount.h>
  73 #include <net/ipv6.h>
  74 #include <linux/hugetlb.h>
  75 #include <linux/personality.h>
  76 #include <linux/audit.h>
  77 #include <linux/string.h>
  78 #include <linux/selinux.h>
  79 #include <linux/mutex.h>
  80 #include <linux/posix-timers.h>
  81 #include <linux/syslog.h>
  82 #include <linux/user_namespace.h>
  83
  84 #include "avc.h"
  85 #include "objsec.h"
  86 #include "netif.h"
  87 #include "netnode.h"
  88 #include "netport.h"
  89 #include "xfrm.h"
  90 #include "netlabel.h"
  91 #include "audit.h"
  92
  93 #define NUM_SEL_MNT_OPTS 5
  94
  95 extern int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm);
  96 extern struct security_operations *security_ops;
  97
  98 /* SECMARK reference count */
  99 atomic_t selinux_secmark_refcount = ATOMIC_INIT(0);
 100
 101 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
 102 int selinux_enforcing;
 103
 104 static int __init enforcing_setup(char *str)
 105 {
 106         unsigned long enforcing;
 107         if (!strict_strtoul(str, 0, &enforcing))
 108                 selinux_enforcing = enforcing ? 1 : 0;
 109         return 1;
 110 }
 111 __setup("enforcing=", enforcing_setup);
 112 #endif
 113
 114 #ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
 115 int selinux_enabled = CONFIG_SECURITY_SELINUX_BOOTPARAM_VALUE;
 116
 117 static int __init selinux_enabled_setup(char *str)
 118 {
 119         unsigned long enabled;
 120         if (!strict_strtoul(str, 0, &enabled))
 121                 selinux_enabled = enabled ? 1 : 0;
 122         return 1;
 123 }
 124 __setup("selinux=", selinux_enabled_setup);
 125 #else
 126 int selinux_enabled = 1;
 127 #endif
 128
 129 static struct kmem_cache *sel_inode_cache;
 130
 131 /**
 132  * selinux_secmark_enabled - Check to see if SECMARK is currently enabled
 133  *
 134  * Description:
 135  * This function checks the SECMARK reference counter to see if any SECMARK
 136  * targets are currently configured, if the reference counter is greater than
 137  * zero SECMARK is considered to be enabled.  Returns true (1) if SECMARK is
 138  * enabled, false (0) if SECMARK is disabled.
 139  *
 140  */
 141 static int selinux_secmark_enabled(void)
 142 {
 143         return (atomic_read(&selinux_secmark_refcount) > 0);
 144 }
 145
 146 /*
 147  * initialise the security for the init task
 148  */
 149 static void cred_init_security(void)
 150 {
 151         struct cred *cred = (struct cred *) current->real_cred;
 152         struct task_security_struct *tsec;
 153
 154         tsec = kzalloc(sizeof(struct task_security_struct), GFP_KERNEL);
 155         if (!tsec)
 156                 panic("SELinux:  Failed to initialize initial task.\n");
 157
 158         tsec->osid = tsec->sid = SECINITSID_KERNEL;
 159         cred->security = tsec;
 160 }
 161
 162 /*
 163  * get the security ID of a set of credentials
 164  */
 165 static inline u32 cred_sid(const struct cred *cred)
 166 {
 167         const struct task_security_struct *tsec;
 168
 169         tsec = cred->security;
 170         return tsec->sid;
 171 }
 172
 173 /*
 174  * get the objective security ID of a task
 175  */
 176 static inline u32 task_sid(const struct task_struct *task)
 177 {
 178         u32 sid;
 179
 180         rcu_read_lock();
 181         sid = cred_sid(__task_cred(task));
 182         rcu_read_unlock();
 183         return sid;
 184 }
 185
 186 /*
 187  * get the subjective security ID of the current task
 188  */
 189 static inline u32 current_sid(void)
 190 {
 191         const struct task_security_struct *tsec = current_security();
 192
 193         return tsec->sid;
 194 }
 195
 196 /* Allocate and free functions for each kind of security blob. */
 197
 198 static int inode_alloc_security(struct inode *inode)
 199 {
 200         struct inode_security_struct *isec;
 201         u32 sid = current_sid();
 202
 203         isec = kmem_cache_zalloc(sel_inode_cache, GFP_NOFS);
 204         if (!isec)
 205                 return -ENOMEM;
 206
 207         mutex_init(&isec->lock);
 208         INIT_LIST_HEAD(&isec->list);
 209         isec->inode = inode;
 210         isec->sid = SECINITSID_UNLABELED;
 211         isec->sclass = SECCLASS_FILE;
 212         isec->task_sid = sid;
 213         inode->i_security = isec;
 214
 215         return 0;
 216 }
 217
 218 static void inode_free_security(struct inode *inode)
 219 {
 220         struct inode_security_struct *isec = inode->i_security;
 221         struct superblock_security_struct *sbsec = inode->i_sb->s_security;
 222
 223         spin_lock(&sbsec->isec_lock);
 224         if (!list_empty(&isec->list))
 225                 list_del_init(&isec->list);
 226         spin_unlock(&sbsec->isec_lock);
 227
 228         inode->i_security = NULL;
 229         kmem_cache_free(sel_inode_cache, isec);
 230 }
 231
 232 static int file_alloc_security(struct file *file)
 233 {
 234         struct file_security_struct *fsec;
 235         u32 sid = current_sid();
 236
 237         fsec = kzalloc(sizeof(struct file_security_struct), GFP_KERNEL);
 238         if (!fsec)
 239                 return -ENOMEM;
 240
 241         fsec->sid = sid;
 242         fsec->fown_sid = sid;
 243         file->f_security = fsec;
 244
 245         return 0;
 246 }
 247
 248 static void file_free_security(struct file *file)
 249 {
 250         struct file_security_struct *fsec = file->f_security;
 251         file->f_security = NULL;
 252         kfree(fsec);
 253 }
 254
 255 static int superblock_alloc_security(struct super_block *sb)
 256 {
 257         struct superblock_security_struct *sbsec;
 258
 259         sbsec = kzalloc(sizeof(struct superblock_security_struct), GFP_KERNEL);
 260         if (!sbsec)
 261                 return -ENOMEM;
 262
 263         mutex_init(&sbsec->lock);
 264         INIT_LIST_HEAD(&sbsec->isec_head);
 265         spin_lock_init(&sbsec->isec_lock);
 266         sbsec->sb = sb;
 267         sbsec->sid = SECINITSID_UNLABELED;
 268         sbsec->def_sid = SECINITSID_FILE;
 269         sbsec->mntpoint_sid = SECINITSID_UNLABELED;
 270         sb->s_security = sbsec;
 271
 272         return 0;
 273 }
 274
 275 static void superblock_free_security(struct super_block *sb)
 276 {
 277         struct superblock_security_struct *sbsec = sb->s_security;
 278         sb->s_security = NULL;
 279         kfree(sbsec);
 280 }
 281
 282 /* The security server must be initialized before
 283    any labeling or access decisions can be provided. */
 284 extern int ss_initialized;
 285
 286 /* The file system's label must be initialized prior to use. */
 287
 288 static const char *labeling_behaviors[6] = {
 289         "uses xattr",
 290         "uses transition SIDs",
 291         "uses task SIDs",
 292         "uses genfs_contexts",
 293         "not configured for labeling",
 294         "uses mountpoint labeling",
 295 };
 296
 297 static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry);
 298
 299 static inline int inode_doinit(struct inode *inode)
 300 {
 301         return inode_doinit_with_dentry(inode, NULL);
 302 }
 303
 304 enum {
 305         Opt_error = -1,
 306         Opt_context = 1,
 307         Opt_fscontext = 2,
 308         Opt_defcontext = 3,
 309         Opt_rootcontext = 4,
 310         Opt_labelsupport = 5,
 311 };
 312
 313 static const match_table_t tokens = {
 314         {Opt_context, CONTEXT_STR "%s"},
 315         {Opt_fscontext, FSCONTEXT_STR "%s"},
 316         {Opt_defcontext, DEFCONTEXT_STR "%s"},
 317         {Opt_rootcontext, ROOTCONTEXT_STR "%s"},
 318         {Opt_labelsupport, LABELSUPP_STR},
 319         {Opt_error, NULL},
 320 };
 321
 322 #define SEL_MOUNT_FAIL_MSG "SELinux:  duplicate or incompatible mount options\n"
 323
 324 static int may_context_mount_sb_relabel(u32 sid,
 325                         struct superblock_security_struct *sbsec,
 326                         const struct cred *cred)
 327 {
 328         const struct task_security_struct *tsec = cred->security;
 329         int rc;
 330
 331         rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
 332                           FILESYSTEM__RELABELFROM, NULL);
 333         if (rc)
 334                 return rc;
 335
 336         rc = avc_has_perm(tsec->sid, sid, SECCLASS_FILESYSTEM,
 337                           FILESYSTEM__RELABELTO, NULL);
 338         return rc;
 339 }
 340
 341 static int may_context_mount_inode_relabel(u32 sid,
 342                         struct superblock_security_struct *sbsec,
 343                         const struct cred *cred)
 344 {
 345         const struct task_security_struct *tsec = cred->security;
 346         int rc;
 347         rc = avc_has_perm(tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM,
 348                           FILESYSTEM__RELABELFROM, NULL);
 349         if (rc)
 350                 return rc;
 351
 352         rc = avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM,
 353                           FILESYSTEM__ASSOCIATE, NULL);
 354         return rc;
 355 }
 356
 357 static int sb_finish_set_opts(struct super_block *sb)
 358 {
 359         struct superblock_security_struct *sbsec = sb->s_security;
 360         struct dentry *root = sb->s_root;
 361         struct inode *root_inode = root->d_inode;
 362         int rc = 0;
 363
 364         if (sbsec->behavior == SECURITY_FS_USE_XATTR) {
 365                 /* Make sure that the xattr handler exists and that no
 366                    error other than -ENODATA is returned by getxattr on
 367                    the root directory.  -ENODATA is ok, as this may be
 368                    the first boot of the SELinux kernel before we have
 369                    assigned xattr values to the filesystem. */
 370                 if (!root_inode->i_op->getxattr) {
 371                         printk(KERN_WARNING "SELinux: (dev %s, type %s) has no "
 372                                "xattr support\n", sb->s_id, sb->s_type->name);
 373                         rc = -EOPNOTSUPP;
 374                         goto out;
 375                 }
 376                 rc = root_inode->i_op->getxattr(root, XATTR_NAME_SELINUX, NULL, 0);
 377                 if (rc < 0 && rc != -ENODATA) {
 378                         if (rc == -EOPNOTSUPP)
 379                                 printk(KERN_WARNING "SELinux: (dev %s, type "
 380                                        "%s) has no security xattr handler\n",
 381                                        sb->s_id, sb->s_type->name);
 382                         else
 383                                 printk(KERN_WARNING "SELinux: (dev %s, type "
 384                                        "%s) getxattr errno %d\n", sb->s_id,
 385                                        sb->s_type->name, -rc);
 386                         goto out;
 387                 }
 388         }
 389
 390         sbsec->flags |= (SE_SBINITIALIZED | SE_SBLABELSUPP);
 391
 392         if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
 393                 printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n",
 394                        sb->s_id, sb->s_type->name);
 395         else
 396                 printk(KERN_DEBUG "SELinux: initialized (dev %s, type %s), %s\n",
 397                        sb->s_id, sb->s_type->name,
 398                        labeling_behaviors[sbsec->behavior-1]);
 399
 400         if (sbsec->behavior == SECURITY_FS_USE_GENFS ||
 401             sbsec->behavior == SECURITY_FS_USE_MNTPOINT ||
 402             sbsec->behavior == SECURITY_FS_USE_NONE ||
 403             sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
 404                 sbsec->flags &= ~SE_SBLABELSUPP;
 405
 406         /* Special handling for sysfs. Is genfs but also has setxattr handler*/
 407         if (strncmp(sb->s_type->name, "sysfs", sizeof("sysfs")) == 0)
 408                 sbsec->flags |= SE_SBLABELSUPP;
 409
 410         /* Initialize the root inode. */
 411         rc = inode_doinit_with_dentry(root_inode, root);
 412
 413         /* Initialize any other inodes associated with the superblock, e.g.
 414            inodes created prior to initial policy load or inodes created
 415            during get_sb by a pseudo filesystem that directly
 416            populates itself. */
 417         spin_lock(&sbsec->isec_lock);
 418 next_inode:
 419         if (!list_empty(&sbsec->isec_head)) {
 420                 struct inode_security_struct *isec =
 421                                 list_entry(sbsec->isec_head.next,
 422                                            struct inode_security_struct, list);
 423                 struct inode *inode = isec->inode;
 424                 spin_unlock(&sbsec->isec_lock);
 425                 inode = igrab(inode);
 426                 if (inode) {
 427                         if (!IS_PRIVATE(inode))
 428                                 inode_doinit(inode);
 429                         iput(inode);
 430                 }
 431                 spin_lock(&sbsec->isec_lock);
 432                 list_del_init(&isec->list);
 433                 goto next_inode;
 434         }
 435         spin_unlock(&sbsec->isec_lock);
 436 out:
 437         return rc;
 438 }
 439
 440 /*
 441  * This function should allow an FS to ask what it's mount security
 442  * options were so it can use those later for submounts, displaying
 443  * mount options, or whatever.
 444  */
 445 static int selinux_get_mnt_opts(const struct super_block *sb,
 446                                 struct security_mnt_opts *opts)
 447 {
 448         int rc = 0, i;
 449         struct superblock_security_struct *sbsec = sb->s_security;
 450         char *context = NULL;
 451         u32 len;
 452         char tmp;
 453
 454         security_init_mnt_opts(opts);
 455
 456         if (!(sbsec->flags & SE_SBINITIALIZED))
 457                 return -EINVAL;
 458
 459         if (!ss_initialized)
 460                 return -EINVAL;
 461
 462         tmp = sbsec->flags & SE_MNTMASK;
 463         /* count the number of mount options for this sb */
 464         for (i = 0; i < 8; i++) {
 465                 if (tmp & 0x01)
 466                         opts->num_mnt_opts++;
 467                 tmp >>= 1;
 468         }
 469         /* Check if the Label support flag is set */
 470         if (sbsec->flags & SE_SBLABELSUPP)
 471                 opts->num_mnt_opts++;
 472
 473         opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC);
 474         if (!opts->mnt_opts) {
 475                 rc = -ENOMEM;
 476                 goto out_free;
 477         }
 478
 479         opts->mnt_opts_flags = kcalloc(opts->num_mnt_opts, sizeof(int), GFP_ATOMIC);
 480         if (!opts->mnt_opts_flags) {
 481                 rc = -ENOMEM;
 482                 goto out_free;
 483         }
 484
 485         i = 0;
 486         if (sbsec->flags & FSCONTEXT_MNT) {
 487                 rc = security_sid_to_context(sbsec->sid, &context, &len);
 488                 if (rc)
 489                         goto out_free;
 490                 opts->mnt_opts[i] = context;
 491                 opts->mnt_opts_flags[i++] = FSCONTEXT_MNT;
 492         }
 493         if (sbsec->flags & CONTEXT_MNT) {
 494                 rc = security_sid_to_context(sbsec->mntpoint_sid, &context, &len);
 495                 if (rc)
 496                         goto out_free;
 497                 opts->mnt_opts[i] = context;
 498                 opts->mnt_opts_flags[i++] = CONTEXT_MNT;
 499         }
 500         if (sbsec->flags & DEFCONTEXT_MNT) {
 501                 rc = security_sid_to_context(sbsec->def_sid, &context, &len);
 502                 if (rc)
 503                         goto out_free;
 504                 opts->mnt_opts[i] = context;
 505                 opts->mnt_opts_flags[i++] = DEFCONTEXT_MNT;
 506         }
 507         if (sbsec->flags & ROOTCONTEXT_MNT) {
 508                 struct inode *root = sbsec->sb->s_root->d_inode;
 509                 struct inode_security_struct *isec = root->i_security;
 510
 511                 rc = security_sid_to_context(isec->sid, &context, &len);
 512                 if (rc)
 513                         goto out_free;
 514                 opts->mnt_opts[i] = context;
 515                 opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT;
 516         }
 517         if (sbsec->flags & SE_SBLABELSUPP) {
 518                 opts->mnt_opts[i] = NULL;
 519                 opts->mnt_opts_flags[i++] = SE_SBLABELSUPP;
 520         }
 521
 522         BUG_ON(i != opts->num_mnt_opts);
 523
 524         return 0;
 525
 526 out_free:
 527         security_free_mnt_opts(opts);
 528         return rc;
 529 }
 530
 531 static int bad_option(struct superblock_security_struct *sbsec, char flag,
 532                       u32 old_sid, u32 new_sid)
 533 {
 534         char mnt_flags = sbsec->flags & SE_MNTMASK;
 535
 536         /* check if the old mount command had the same options */
 537         if (sbsec->flags & SE_SBINITIALIZED)
 538                 if (!(sbsec->flags & flag) ||
 539                     (old_sid != new_sid))
 540                         return 1;
 541
 542         /* check if we were passed the same options twice,
 543          * aka someone passed context=a,context=b
 544          */
 545         if (!(sbsec->flags & SE_SBINITIALIZED))
 546                 if (mnt_flags & flag)
 547                         return 1;
 548         return 0;
 549 }
 550
 551 /*
 552  * Allow filesystems with binary mount data to explicitly set mount point
 553  * labeling information.
 554  */
 555 static int selinux_set_mnt_opts(struct super_block *sb,
 556                                 struct security_mnt_opts *opts)
 557 {
 558         const struct cred *cred = current_cred();
 559         int rc = 0, i;
 560         struct superblock_security_struct *sbsec = sb->s_security;
 561         const char *name = sb->s_type->name;
 562         struct inode *inode = sbsec->sb->s_root->d_inode;
 563         struct inode_security_struct *root_isec = inode->i_security;
 564         u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
 565         u32 defcontext_sid = 0;
 566         char **mount_options = opts->mnt_opts;
 567         int *flags = opts->mnt_opts_flags;
 568         int num_opts = opts->num_mnt_opts;
 569
 570         mutex_lock(&sbsec->lock);
 571
 572         if (!ss_initialized) {
 573                 if (!num_opts) {
 574                         /* Defer initialization until selinux_complete_init,
 575                            after the initial policy is loaded and the security
 576                            server is ready to handle calls. */
 577                         goto out;
 578                 }
 579                 rc = -EINVAL;
 580                 printk(KERN_WARNING "SELinux: Unable to set superblock options "
 581                         "before the security server is initialized\n");
 582                 goto out;
 583         }
 584
 585         /*
 586          * Binary mount data FS will come through this function twice.  Once
 587          * from an explicit call and once from the generic calls from the vfs.
 588          * Since the generic VFS calls will not contain any security mount data
 589          * we need to skip the double mount verification.
 590          *
 591          * This does open a hole in which we will not notice if the first
 592          * mount using this sb set explict options and a second mount using
 593          * this sb does not set any security options.  (The first options
 594          * will be used for both mounts)
 595          */
 596         if ((sbsec->flags & SE_SBINITIALIZED) && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
 597             && (num_opts == 0))
 598                 goto out;
 599
 600         /*
 601          * parse the mount options, check if they are valid sids.
 602          * also check if someone is trying to mount the same sb more
 603          * than once with different security options.
 604          */
 605         for (i = 0; i < num_opts; i++) {
 606                 u32 sid;
 607
 608                 if (flags[i] == SE_SBLABELSUPP)
 609                         continue;
 610                 rc = security_context_to_sid(mount_options[i],
 611                                              strlen(mount_options[i]), &sid);
 612                 if (rc) {
 613                         printk(KERN_WARNING "SELinux: security_context_to_sid"
 614                                "(%s) failed for (dev %s, type %s) errno=%d\n",
 615                                mount_options[i], sb->s_id, name, rc);
 616                         goto out;
 617                 }
 618                 switch (flags[i]) {
 619                 case FSCONTEXT_MNT:
 620                         fscontext_sid = sid;
 621
 622                         if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid,
 623                                         fscontext_sid))
 624                                 goto out_double_mount;
 625
 626                         sbsec->flags |= FSCONTEXT_MNT;
 627                         break;
 628                 case CONTEXT_MNT:
 629                         context_sid = sid;
 630
 631                         if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid,
 632                                         context_sid))
 633                                 goto out_double_mount;
 634
 635                         sbsec->flags |= CONTEXT_MNT;
 636                         break;
 637                 case ROOTCONTEXT_MNT:
 638                         rootcontext_sid = sid;
 639
 640                         if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid,
 641                                         rootcontext_sid))
 642                                 goto out_double_mount;
 643
 644                         sbsec->flags |= ROOTCONTEXT_MNT;
 645
 646                         break;
 647                 case DEFCONTEXT_MNT:
 648                         defcontext_sid = sid;
 649
 650                         if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid,
 651                                         defcontext_sid))
 652                                 goto out_double_mount;
 653
 654                         sbsec->flags |= DEFCONTEXT_MNT;
 655
 656                         break;
 657                 default:
 658                         rc = -EINVAL;
 659                         goto out;
 660                 }
 661         }
 662
 663         if (sbsec->flags & SE_SBINITIALIZED) {
 664                 /* previously mounted with options, but not on this attempt? */
 665                 if ((sbsec->flags & SE_MNTMASK) && !num_opts)
 666                         goto out_double_mount;
 667                 rc = 0;
 668                 goto out;
 669         }
 670
 671         if (strcmp(sb->s_type->name, "proc") == 0)
 672                 sbsec->flags |= SE_SBPROC;
 673
 674         /* Determine the labeling behavior to use for this filesystem type. */
 675         rc = security_fs_use((sbsec->flags & SE_SBPROC) ? "proc" : sb->s_type->name, &sbsec->behavior, &sbsec->sid);
 676         if (rc) {
 677                 printk(KERN_WARNING "%s: security_fs_use(%s) returned %d\n",
 678                        __func__, sb->s_type->name, rc);
 679                 goto out;
 680         }
 681
 682         /* sets the context of the superblock for the fs being mounted. */
 683         if (fscontext_sid) {
 684                 rc = may_context_mount_sb_relabel(fscontext_sid, sbsec, cred);
 685                 if (rc)
 686                         goto out;
 687
 688                 sbsec->sid = fscontext_sid;
 689         }
 690
 691         /*
 692          * Switch to using mount point labeling behavior.
 693          * sets the label used on all file below the mountpoint, and will set
 694          * the superblock context if not already set.
 695          */
 696         if (context_sid) {
 697                 if (!fscontext_sid) {
 698                         rc = may_context_mount_sb_relabel(context_sid, sbsec,
 699                                                           cred);
 700                         if (rc)
 701                                 goto out;
 702                         sbsec->sid = context_sid;
 703                 } else {
 704                         rc = may_context_mount_inode_relabel(context_sid, sbsec,
 705                                                              cred);
 706                         if (rc)
 707                                 goto out;
 708                 }
 709                 if (!rootcontext_sid)
 710                         rootcontext_sid = context_sid;
 711
 712                 sbsec->mntpoint_sid = context_sid;
 713                 sbsec->behavior = SECURITY_FS_USE_MNTPOINT;
 714         }
 715
 716         if (rootcontext_sid) {
 717                 rc = may_context_mount_inode_relabel(rootcontext_sid, sbsec,
 718                                                      cred);
 719                 if (rc)
 720                         goto out;
 721
 722                 root_isec->sid = rootcontext_sid;
 723                 root_isec->initialized = 1;
 724         }
 725
 726         if (defcontext_sid) {
 727                 if (sbsec->behavior != SECURITY_FS_USE_XATTR) {
 728                         rc = -EINVAL;
 729                         printk(KERN_WARNING "SELinux: defcontext option is "
 730                                "invalid for this filesystem type\n");
 731                         goto out;
 732                 }
 733
 734                 if (defcontext_sid != sbsec->def_sid) {
 735                         rc = may_context_mount_inode_relabel(defcontext_sid,
 736                                                              sbsec, cred);
 737                         if (rc)
 738                                 goto out;
 739                 }
 740
 741                 sbsec->def_sid = defcontext_sid;
 742         }
 743
 744         rc = sb_finish_set_opts(sb);
 745 out:
 746         mutex_unlock(&sbsec->lock);
 747         return rc;
 748 out_double_mount:
 749         rc = -EINVAL;
 750         printk(KERN_WARNING "SELinux: mount invalid.  Same superblock, different "
 751                "security settings for (dev %s, type %s)\n", sb->s_id, name);
 752         goto out;
 753 }
 754
 755 static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
 756                                         struct super_block *newsb)
 757 {
 758         const struct superblock_security_struct *oldsbsec = oldsb->s_security;
 759         struct superblock_security_struct *newsbsec = newsb->s_security;
 760
 761         int set_fscontext =     (oldsbsec->flags & FSCONTEXT_MNT);
 762         int set_context =       (oldsbsec->flags & CONTEXT_MNT);
 763         int set_rootcontext =   (oldsbsec->flags & ROOTCONTEXT_MNT);
 764
 765         /*
 766          * if the parent was able to be mounted it clearly had no special lsm
 767          * mount options.  thus we can safely deal with this superblock later
 768          */
 769         if (!ss_initialized)
 770                 return;
 771
 772         /* how can we clone if the old one wasn't set up?? */
 773         BUG_ON(!(oldsbsec->flags & SE_SBINITIALIZED));
 774
 775         /* if fs is reusing a sb, just let its options stand... */
 776         if (newsbsec->flags & SE_SBINITIALIZED)
 777                 return;
 778
 779         mutex_lock(&newsbsec->lock);
 780
 781         newsbsec->flags = oldsbsec->flags;
 782
 783         newsbsec->sid = oldsbsec->sid;
 784         newsbsec->def_sid = oldsbsec->def_sid;
 785         newsbsec->behavior = oldsbsec->behavior;
 786
 787         if (set_context) {
 788                 u32 sid = oldsbsec->mntpoint_sid;
 789
 790                 if (!set_fscontext)
 791                         newsbsec->sid = sid;
 792                 if (!set_rootcontext) {
 793                         struct inode *newinode = newsb->s_root->d_inode;
 794                         struct inode_security_struct *newisec = newinode->i_security;
 795                         newisec->sid = sid;
 796                 }
 797                 newsbsec->mntpoint_sid = sid;
 798         }
 799         if (set_rootcontext) {
 800                 const struct inode *oldinode = oldsb->s_root->d_inode;
 801                 const struct inode_security_struct *oldisec = oldinode->i_security;
 802                 struct inode *newinode = newsb->s_root->d_inode;
 803                 struct inode_security_struct *newisec = newinode->i_security;
 804
 805                 newisec->sid = oldisec->sid;
 806         }
 807
 808         sb_finish_set_opts(newsb);
 809         mutex_unlock(&newsbsec->lock);
 810 }
 811
 812 static int selinux_parse_opts_str(char *options,
 813                                   struct security_mnt_opts *opts)
 814 {
 815         char *p;
 816         char *context = NULL, *defcontext = NULL;
 817         char *fscontext = NULL, *rootcontext = NULL;
 818         int rc, num_mnt_opts = 0;
 819
 820         opts->num_mnt_opts = 0;
 821
 822         /* Standard string-based options. */
 823         while ((p = strsep(&options, "|")) != NULL) {
 824                 int token;
 825                 substring_t args[MAX_OPT_ARGS];
 826
 827                 if (!*p)
 828                         continue;
 829
 830                 token = match_token(p, tokens, args);
 831
 832                 switch (token) {
 833                 case Opt_context:
 834                         if (context || defcontext) {
 835                                 rc = -EINVAL;
 836                                 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
 837                                 goto out_err;
 838                         }
 839                         context = match_strdup(&args[0]);
 840                         if (!context) {
 841                                 rc = -ENOMEM;
 842                                 goto out_err;
 843                         }
 844                         break;
 845
 846                 case Opt_fscontext:
 847                         if (fscontext) {
 848                                 rc = -EINVAL;
 849                                 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
 850                                 goto out_err;
 851                         }
 852                         fscontext = match_strdup(&args[0]);
 853                         if (!fscontext) {
 854                                 rc = -ENOMEM;
 855                                 goto out_err;
 856                         }
 857                         break;
 858
 859                 case Opt_rootcontext:
 860                         if (rootcontext) {
 861                                 rc = -EINVAL;
 862                                 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
 863                                 goto out_err;
 864                         }
 865                         rootcontext = match_strdup(&args[0]);
 866                         if (!rootcontext) {
 867                                 rc = -ENOMEM;
 868                                 goto out_err;
 869                         }
 870                         break;
 871
 872                 case Opt_defcontext:
 873                         if (context || defcontext) {
 874                                 rc = -EINVAL;
 875                                 printk(KERN_WARNING SEL_MOUNT_FAIL_MSG);
 876                                 goto out_err;
 877                         }
 878                         defcontext = match_strdup(&args[0]);
 879                         if (!defcontext) {
 880                                 rc = -ENOMEM;
 881                                 goto out_err;
 882                         }
 883                         break;
 884                 case Opt_labelsupport:
 885                         break;
 886                 default:
 887                         rc = -EINVAL;
 888                         printk(KERN_WARNING "SELinux:  unknown mount option\n");
 889                         goto out_err;
 890
 891                 }
 892         }
 893
 894         rc = -ENOMEM;
 895         opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_ATOMIC);
 896         if (!opts->mnt_opts)
 897                 goto out_err;
 898
 899         opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int), GFP_ATOMIC);
 900         if (!opts->mnt_opts_flags) {
 901                 kfree(opts->mnt_opts);
 902                 goto out_err;
 903         }
 904
 905         if (fscontext) {
 906                 opts->mnt_opts[num_mnt_opts] = fscontext;
 907                 opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
 908         }
 909         if (context) {
 910                 opts->mnt_opts[num_mnt_opts] = context;
 911                 opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
 912         }
 913         if (rootcontext) {
 914                 opts->mnt_opts[num_mnt_opts] = rootcontext;
 915                 opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
 916         }
 917         if (defcontext) {
 918                 opts->mnt_opts[num_mnt_opts] = defcontext;
 919                 opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
 920         }
 921
 922         opts->num_mnt_opts = num_mnt_opts;
 923         return 0;
 924
 925 out_err:
 926         kfree(context);
 927         kfree(defcontext);
 928         kfree(fscontext);
 929         kfree(rootcontext);
 930         return rc;
 931 }
 932 /*
 933  * string mount options parsing and call set the sbsec
 934  */
 935 static int superblock_doinit(struct super_block *sb, void *data)
 936 {
 937         int rc = 0;
 938         char *options = data;
 939         struct security_mnt_opts opts;
 940
 941         security_init_mnt_opts(&opts);
 942
 943         if (!data)
 944                 goto out;
 945
 946         BUG_ON(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA);
 947
 948         rc = selinux_parse_opts_str(options, &opts);
 949         if (rc)
 950                 goto out_err;
 951
 952 out:
 953         rc = selinux_set_mnt_opts(sb, &opts);
 954
 955 out_err:
 956         security_free_mnt_opts(&opts);
 957         return rc;
 958 }
 959
 960 static void selinux_write_opts(struct seq_file *m,
 961                                struct security_mnt_opts *opts)
 962 {
 963         int i;
 964         char *prefix;
 965
 966         for (i = 0; i < opts->num_mnt_opts; i++) {
 967                 char *has_comma;
 968
 969                 if (opts->mnt_opts[i])
 970                         has_comma = strchr(opts->mnt_opts[i], ',');
 971                 else
 972                         has_comma = NULL;
 973
 974                 switch (opts->mnt_opts_flags[i]) {
 975                 case CONTEXT_MNT:
 976                         prefix = CONTEXT_STR;
 977                         break;
 978                 case FSCONTEXT_MNT:
 979                         prefix = FSCONTEXT_STR;
 980                         break;
 981                 case ROOTCONTEXT_MNT:
 982                         prefix = ROOTCONTEXT_STR;
 983                         break;
 984                 case DEFCONTEXT_MNT:
 985                         prefix = DEFCONTEXT_STR;
 986                         break;
 987                 case SE_SBLABELSUPP:
 988                         seq_putc(m, ',');
 989                         seq_puts(m, LABELSUPP_STR);
 990                         continue;
 991                 default:
 992                         BUG();
 993                         return;
 994                 };
 995                 /* we need a comma before each option */
 996                 seq_putc(m, ',');
 997                 seq_puts(m, prefix);
 998                 if (has_comma)
 999                         seq_putc(m, '\"');
1000                 seq_puts(m, opts->mnt_opts[i]);
1001                 if (has_comma)
1002                         seq_putc(m, '\"');
1003         }
1004 }
1005
1006 static int selinux_sb_show_options(struct seq_file *m, struct super_block *sb)
1007 {
1008         struct security_mnt_opts opts;
1009         int rc;
1010
1011         rc = selinux_get_mnt_opts(sb, &opts);
1012         if (rc) {
1013                 /* before policy load we may get EINVAL, don't show anything */
1014                 if (rc == -EINVAL)
1015                         rc = 0;
1016                 return rc;
1017         }
1018
1019         selinux_write_opts(m, &opts);
1020
1021         security_free_mnt_opts(&opts);
1022
1023         return rc;
1024 }
1025
1026 static inline u16 inode_mode_to_security_class(umode_t mode)
1027 {
1028         switch (mode & S_IFMT) {
1029         case S_IFSOCK:
1030                 return SECCLASS_SOCK_FILE;
1031         case S_IFLNK:
1032                 return SECCLASS_LNK_FILE;
1033         case S_IFREG:
1034                 return SECCLASS_FILE;
1035         case S_IFBLK:
1036                 return SECCLASS_BLK_FILE;
1037         case S_IFDIR:
1038                 return SECCLASS_DIR;
1039         case S_IFCHR:
1040                 return SECCLASS_CHR_FILE;
1041         case S_IFIFO:
1042                 return SECCLASS_FIFO_FILE;
1043
1044         }
1045
1046         return SECCLASS_FILE;
1047 }
1048
1049 static inline int default_protocol_stream(int protocol)
1050 {
1051         return (protocol == IPPROTO_IP || protocol == IPPROTO_TCP);
1052 }
1053
1054 static inline int default_protocol_dgram(int protocol)
1055 {
1056         return (protocol == IPPROTO_IP || protocol == IPPROTO_UDP);
1057 }
1058
1059 static inline u16 socket_type_to_security_class(int family, int type, int protocol)
1060 {
1061         switch (family) {
1062         case PF_UNIX:
1063                 switch (type) {
1064                 case SOCK_STREAM:
1065                 case SOCK_SEQPACKET:
1066                         return SECCLASS_UNIX_STREAM_SOCKET;
1067                 case SOCK_DGRAM:
1068                         return SECCLASS_UNIX_DGRAM_SOCKET;
1069                 }
1070                 break;
1071         case PF_INET:
1072         case PF_INET6:
1073                 switch (type) {
1074                 case SOCK_STREAM:
1075                         if (default_protocol_stream(protocol))
1076                                 return SECCLASS_TCP_SOCKET;
1077                         else
1078                                 return SECCLASS_RAWIP_SOCKET;
1079                 case SOCK_DGRAM:
1080                         if (default_protocol_dgram(protocol))
1081                                 return SECCLASS_UDP_SOCKET;
1082                         else
1083                                 return SECCLASS_RAWIP_SOCKET;
1084                 case SOCK_DCCP:
1085                         return SECCLASS_DCCP_SOCKET;
1086                 default:
1087                         return SECCLASS_RAWIP_SOCKET;
1088                 }
1089                 break;
1090         case PF_NETLINK:
1091                 switch (protocol) {
1092                 case NETLINK_ROUTE:
1093                         return SECCLASS_NETLINK_ROUTE_SOCKET;
1094                 case NETLINK_FIREWALL:
1095                         return SECCLASS_NETLINK_FIREWALL_SOCKET;
1096                 case NETLINK_INET_DIAG:
1097                         return SECCLASS_NETLINK_TCPDIAG_SOCKET;
1098                 case NETLINK_NFLOG:
1099                         return SECCLASS_NETLINK_NFLOG_SOCKET;
1100                 case NETLINK_XFRM:
1101                         return SECCLASS_NETLINK_XFRM_SOCKET;
1102                 case NETLINK_SELINUX:
1103                         return SECCLASS_NETLINK_SELINUX_SOCKET;
1104                 case NETLINK_AUDIT:
1105                         return SECCLASS_NETLINK_AUDIT_SOCKET;
1106                 case NETLINK_IP6_FW:
1107                         return SECCLASS_NETLINK_IP6FW_SOCKET;
1108                 case NETLINK_DNRTMSG:
1109                         return SECCLASS_NETLINK_DNRT_SOCKET;
1110                 case NETLINK_KOBJECT_UEVENT:
1111                         return SECCLASS_NETLINK_KOBJECT_UEVENT_SOCKET;
1112                 default:
1113                         return SECCLASS_NETLINK_SOCKET;
1114                 }
1115         case PF_PACKET:
1116                 return SECCLASS_PACKET_SOCKET;
1117         case PF_KEY:
1118                 return SECCLASS_KEY_SOCKET;
1119         case PF_APPLETALK:
1120                 return SECCLASS_APPLETALK_SOCKET;
1121         }
1122
1123         return SECCLASS_SOCKET;
1124 }
1125
1126 #ifdef CONFIG_PROC_FS
1127 static int selinux_proc_get_sid(struct dentry *dentry,
1128                                 u16 tclass,
1129                                 u32 *sid)
1130 {
1131         int rc;
1132         char *buffer, *path;
1133
1134         buffer = (char *)__get_free_page(GFP_KERNEL);
1135         if (!buffer)
1136                 return -ENOMEM;
1137
1138         path = dentry_path_raw(dentry, buffer, PAGE_SIZE);
1139         if (IS_ERR(path))
1140                 rc = PTR_ERR(path);
1141         else {
1142                 /* each process gets a /proc/PID/ entry. Strip off the
1143                  * PID part to get a valid selinux labeling.
1144                  * e.g. /proc/1/net/rpc/nfs -> /net/rpc/nfs */
1145                 while (path[1] >= '0' && path[1] <= '9') {
1146                         path[1] = '/';
1147                         path++;
1148                 }
1149                 rc = security_genfs_sid("proc", path, tclass, sid);
1150         }
1151         free_page((unsigned long)buffer);
1152         return rc;
1153 }
1154 #else
1155 static int selinux_proc_get_sid(struct dentry *dentry,
1156                                 u16 tclass,
1157                                 u32 *sid)
1158 {
1159         return -EINVAL;
1160 }
1161 #endif
1162
1163 /* The inode's security attributes must be initialized before first use. */
1164 static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry)
1165 {
1166         struct superblock_security_struct *sbsec = NULL;
1167         struct inode_security_struct *isec = inode->i_security;
1168         u32 sid;
1169         struct dentry *dentry;
1170 #define INITCONTEXTLEN 255
1171         char *context = NULL;
1172         unsigned len = 0;
1173         int rc = 0;
1174
1175         if (isec->initialized)
1176                 goto out;
1177
1178         mutex_lock(&isec->lock);
1179         if (isec->initialized)
1180                 goto out_unlock;
1181
1182         sbsec = inode->i_sb->s_security;
1183         if (!(sbsec->flags & SE_SBINITIALIZED)) {
1184                 /* Defer initialization until selinux_complete_init,
1185                    after the initial policy is loaded and the security
1186                    server is ready to handle calls. */
1187                 spin_lock(&sbsec->isec_lock);
1188                 if (list_empty(&isec->list))
1189                         list_add(&isec->list, &sbsec->isec_head);
1190                 spin_unlock(&sbsec->isec_lock);
1191                 goto out_unlock;
1192         }
1193
1194         switch (sbsec->behavior) {
1195         case SECURITY_FS_USE_XATTR:
1196                 if (!inode->i_op->getxattr) {
1197                         isec->sid = sbsec->def_sid;
1198                         break;
1199                 }
1200
1201                 /* Need a dentry, since the xattr API requires one.
1202                    Life would be simpler if we could just pass the inode. */
1203                 if (opt_dentry) {
1204                         /* Called from d_instantiate or d_splice_alias. */
1205                         dentry = dget(opt_dentry);
1206                 } else {
1207                         /* Called from selinux_complete_init, try to find a dentry. */
1208                         dentry = d_find_alias(inode);
1209                 }
1210                 if (!dentry) {
1211                         /*
1212                          * this is can be hit on boot when a file is accessed
1213                          * before the policy is loaded.  When we load policy we
1214                          * may find inodes that have no dentry on the
1215                          * sbsec->isec_head list.  No reason to complain as these
1216                          * will get fixed up the next time we go through
1217                          * inode_doinit with a dentry, before these inodes could
1218                          * be used again by userspace.
1219                          */
1220                         goto out_unlock;
1221                 }
1222
1223                 len = INITCONTEXTLEN;
1224                 context = kmalloc(len+1, GFP_NOFS);
1225                 if (!context) {
1226                         rc = -ENOMEM;
1227                         dput(dentry);
1228                         goto out_unlock;
1229                 }
1230                 context[len] = '\0';
1231                 rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
1232                                            context, len);
1233                 if (rc == -ERANGE) {
1234                         kfree(context);
1235
1236                         /* Need a larger buffer.  Query for the right size. */
1237                         rc = inode->i_op->getxattr(dentry, XATTR_NAME_SELINUX,
1238                                                    NULL, 0);
1239                         if (rc < 0) {
1240                                 dput(dentry);
1241                                 goto out_unlock;
1242                         }
1243                         len = rc;
1244                         context = kmalloc(len+1, GFP_NOFS);
1245                         if (!context) {
1246                                 rc = -ENOMEM;
1247                                 dput(dentry);
1248                                 goto out_unlock;
1249                         }
1250                         context[len] = '\0';
1251                         rc = inode->i_op->getxattr(dentry,
1252                                                    XATTR_NAME_SELINUX,
1253                                                    context, len);
1254                 }
1255                 dput(dentry);
1256                 if (rc < 0) {
1257                         if (rc != -ENODATA) {
1258                                 printk(KERN_WARNING "SELinux: %s:  getxattr returned "
1259                                        "%d for dev=%s ino=%ld\n", __func__,
1260                                        -rc, inode->i_sb->s_id, inode->i_ino);
1261                                 kfree(context);
1262                                 goto out_unlock;
1263                         }
1264                         /* Map ENODATA to the default file SID */
1265                         sid = sbsec->def_sid;
1266                         rc = 0;
1267                 } else {
1268                         rc = security_context_to_sid_default(context, rc, &sid,
1269                                                              sbsec->def_sid,
1270                                                              GFP_NOFS);
1271                         if (rc) {
1272                                 char *dev = inode->i_sb->s_id;
1273                                 unsigned long ino = inode->i_ino;
1274
1275                                 if (rc == -EINVAL) {
1276                                         if (printk_ratelimit())
1277                                                 printk(KERN_NOTICE "SELinux: inode=%lu on dev=%s was found to have an invalid "
1278                                                         "context=%s.  This indicates you may need to relabel the inode or the "
1279                                                         "filesystem in question.\n", ino, dev, context);
1280                                 } else {
1281                                         printk(KERN_WARNING "SELinux: %s:  context_to_sid(%s) "
1282                                                "returned %d for dev=%s ino=%ld\n",
1283                                                __func__, context, -rc, dev, ino);
1284                                 }
1285                                 kfree(context);
1286                                 /* Leave with the unlabeled SID */
1287                                 rc = 0;
1288                                 break;
1289                         }
1290                 }
1291                 kfree(context);
1292                 isec->sid = sid;
1293                 break;
1294         case SECURITY_FS_USE_TASK:
1295                 isec->sid = isec->task_sid;
1296                 break;
1297         case SECURITY_FS_USE_TRANS:
1298                 /* Default to the fs SID. */
1299                 isec->sid = sbsec->sid;
1300
1301                 /* Try to obtain a transition SID. */
1302                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1303                 rc = security_transition_sid(isec->task_sid, sbsec->sid,
1304                                              isec->sclass, NULL, &sid);
1305                 if (rc)
1306                         goto out_unlock;
1307                 isec->sid = sid;
1308                 break;
1309         case SECURITY_FS_USE_MNTPOINT:
1310                 isec->sid = sbsec->mntpoint_sid;
1311                 break;
1312         default:
1313                 /* Default to the fs superblock SID. */
1314                 isec->sid = sbsec->sid;
1315
1316                 if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) {
1317                         if (opt_dentry) {
1318                                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1319                                 rc = selinux_proc_get_sid(opt_dentry,
1320                                                           isec->sclass,
1321                                                           &sid);
1322                                 if (rc)
1323                                         goto out_unlock;
1324                                 isec->sid = sid;
1325                         }
1326                 }
1327                 break;
1328         }
1329
1330         isec->initialized = 1;
1331
1332 out_unlock:
1333         mutex_unlock(&isec->lock);
1334 out:
1335         if (isec->sclass == SECCLASS_FILE)
1336                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
1337         return rc;
1338 }
1339
1340 /* Convert a Linux signal to an access vector. */
1341 static inline u32 signal_to_av(int sig)
1342 {
1343         u32 perm = 0;
1344
1345         switch (sig) {
1346         case SIGCHLD:
1347                 /* Commonly granted from child to parent. */
1348                 perm = PROCESS__SIGCHLD;
1349                 break;
1350         case SIGKILL:
1351                 /* Cannot be caught or ignored */
1352                 perm = PROCESS__SIGKILL;
1353                 break;
1354         case SIGSTOP:
1355                 /* Cannot be caught or ignored */
1356                 perm = PROCESS__SIGSTOP;
1357                 break;
1358         default:
1359                 /* All other signals. */
1360                 perm = PROCESS__SIGNAL;
1361                 break;
1362         }
1363
1364         return perm;
1365 }
1366
1367 /*
1368  * Check permission between a pair of credentials
1369  * fork check, ptrace check, etc.
1370  */
1371 static int cred_has_perm(const struct cred *actor,
1372                          const struct cred *target,
1373                          u32 perms)
1374 {
1375         u32 asid = cred_sid(actor), tsid = cred_sid(target);
1376
1377         return avc_has_perm(asid, tsid, SECCLASS_PROCESS, perms, NULL);
1378 }
1379
1380 /*
1381  * Check permission between a pair of tasks, e.g. signal checks,
1382  * fork check, ptrace check, etc.
1383  * tsk1 is the actor and tsk2 is the target
1384  * - this uses the default subjective creds of tsk1
1385  */
1386 static int task_has_perm(const struct task_struct *tsk1,
1387                          const struct task_struct *tsk2,
1388                          u32 perms)
1389 {
1390         const struct task_security_struct *__tsec1, *__tsec2;
1391         u32 sid1, sid2;
1392
1393         rcu_read_lock();
1394         __tsec1 = __task_cred(tsk1)->security;  sid1 = __tsec1->sid;
1395         __tsec2 = __task_cred(tsk2)->security;  sid2 = __tsec2->sid;
1396         rcu_read_unlock();
1397         return avc_has_perm(sid1, sid2, SECCLASS_PROCESS, perms, NULL);
1398 }
1399
1400 /*
1401  * Check permission between current and another task, e.g. signal checks,
1402  * fork check, ptrace check, etc.
1403  * current is the actor and tsk2 is the target
1404  * - this uses current's subjective creds
1405  */
1406 static int current_has_perm(const struct task_struct *tsk,
1407                             u32 perms)
1408 {
1409         u32 sid, tsid;
1410
1411         sid = current_sid();
1412         tsid = task_sid(tsk);
1413         return avc_has_perm(sid, tsid, SECCLASS_PROCESS, perms, NULL);
1414 }
1415
1416 #if CAP_LAST_CAP > 63
1417 #error Fix SELinux to handle capabilities > 63.
1418 #endif
1419
1420 /* Check whether a task is allowed to use a capability. */
1421 static int task_has_capability(struct task_struct *tsk,
1422                                const struct cred *cred,
1423                                int cap, int audit)
1424 {
1425         struct common_audit_data ad;
1426         struct av_decision avd;
1427         u16 sclass;
1428         u32 sid = cred_sid(cred);
1429         u32 av = CAP_TO_MASK(cap);
1430         int rc;
1431
1432         COMMON_AUDIT_DATA_INIT(&ad, CAP);
1433         ad.tsk = tsk;
1434         ad.u.cap = cap;
1435
1436         switch (CAP_TO_INDEX(cap)) {
1437         case 0:
1438                 sclass = SECCLASS_CAPABILITY;
1439                 break;
1440         case 1:
1441                 sclass = SECCLASS_CAPABILITY2;
1442                 break;
1443         default:
1444                 printk(KERN_ERR
1445                        "SELinux:  out of range capability %d\n", cap);
1446                 BUG();
1447                 return -EINVAL;
1448         }
1449
1450         rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);
1451         if (audit == SECURITY_CAP_AUDIT) {
1452                 int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad, 0);
1453                 if (rc2)
1454                         return rc2;
1455         }
1456         return rc;
1457 }
1458
1459 /* Check whether a task is allowed to use a system operation. */
1460 static int task_has_system(struct task_struct *tsk,
1461                            u32 perms)
1462 {
1463         u32 sid = task_sid(tsk);
1464
1465         return avc_has_perm(sid, SECINITSID_KERNEL,
1466                             SECCLASS_SYSTEM, perms, NULL);
1467 }
1468
1469 /* Check whether a task has a particular permission to an inode.
1470    The 'adp' parameter is optional and allows other audit
1471    data to be passed (e.g. the dentry). */
1472 static int inode_has_perm(const struct cred *cred,
1473                           struct inode *inode,
1474                           u32 perms,
1475                           struct common_audit_data *adp,
1476                           unsigned flags)
1477 {
1478         struct inode_security_struct *isec;
1479         u32 sid;
1480
1481         validate_creds(cred);
1482
1483         if (unlikely(IS_PRIVATE(inode)))
1484                 return 0;
1485
1486         sid = cred_sid(cred);
1487         isec = inode->i_security;
1488
1489         return avc_has_perm_flags(sid, isec->sid, isec->sclass, perms, adp, flags);
1490 }
1491
1492 static int inode_has_perm_noadp(const struct cred *cred,
1493                                 struct inode *inode,
1494                                 u32 perms,
1495                                 unsigned flags)
1496 {
1497         struct common_audit_data ad;
1498
1499         COMMON_AUDIT_DATA_INIT(&ad, INODE);
1500         ad.u.inode = inode;
1501         return inode_has_perm(cred, inode, perms, &ad, flags);
1502 }
1503
1504 /* Same as inode_has_perm, but pass explicit audit data containing
1505    the dentry to help the auditing code to more easily generate the
1506    pathname if needed. */
1507 static inline int dentry_has_perm(const struct cred *cred,
1508                                   struct dentry *dentry,
1509                                   u32 av)
1510 {
1511         struct inode *inode = dentry->d_inode;
1512         struct common_audit_data ad;
1513
1514         COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
1515         ad.u.dentry = dentry;
1516         return inode_has_perm(cred, inode, av, &ad, 0);
1517 }
1518
1519 /* Same as inode_has_perm, but pass explicit audit data containing
1520    the path to help the auditing code to more easily generate the
1521    pathname if needed. */
1522 static inline int path_has_perm(const struct cred *cred,
1523                                 struct path *path,
1524                                 u32 av)
1525 {
1526         struct inode *inode = path->dentry->d_inode;
1527         struct common_audit_data ad;
1528
1529         COMMON_AUDIT_DATA_INIT(&ad, PATH);
1530         ad.u.path = *path;
1531         return inode_has_perm(cred, inode, av, &ad, 0);
1532 }
1533
1534 /* Check whether a task can use an open file descriptor to
1535    access an inode in a given way.  Check access to the
1536    descriptor itself, and then use dentry_has_perm to
1537    check a particular permission to the file.
1538    Access to the descriptor is implicitly granted if it
1539    has the same SID as the process.  If av is zero, then
1540    access to the file is not checked, e.g. for cases
1541    where only the descriptor is affected like seek. */
1542 static int file_has_perm(const struct cred *cred,
1543                          struct file *file,
1544                          u32 av)
1545 {
1546         struct file_security_struct *fsec = file->f_security;
1547         struct inode *inode = file->f_path.dentry->d_inode;
1548         struct common_audit_data ad;
1549         u32 sid = cred_sid(cred);
1550         int rc;
1551
1552         COMMON_AUDIT_DATA_INIT(&ad, PATH);
1553         ad.u.path = file->f_path;
1554
1555         if (sid != fsec->sid) {
1556                 rc = avc_has_perm(sid, fsec->sid,
1557                                   SECCLASS_FD,
1558                                   FD__USE,
1559                                   &ad);
1560                 if (rc)
1561                         goto out;
1562         }
1563
1564         /* av is zero if only checking access to the descriptor. */
1565         rc = 0;
1566         if (av)
1567                 rc = inode_has_perm(cred, inode, av, &ad, 0);
1568
1569 out:
1570         return rc;
1571 }
1572
1573 /* Check whether a task can create a file. */
1574 static int may_create(struct inode *dir,
1575                       struct dentry *dentry,
1576                       u16 tclass)
1577 {
1578         const struct task_security_struct *tsec = current_security();
1579         struct inode_security_struct *dsec;
1580         struct superblock_security_struct *sbsec;
1581         u32 sid, newsid;
1582         struct common_audit_data ad;
1583         int rc;
1584
1585         dsec = dir->i_security;
1586         sbsec = dir->i_sb->s_security;
1587
1588         sid = tsec->sid;
1589         newsid = tsec->create_sid;
1590
1591         COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
1592         ad.u.dentry = dentry;
1593
1594         rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR,
1595                           DIR__ADD_NAME | DIR__SEARCH,
1596                           &ad);
1597         if (rc)
1598                 return rc;
1599
1600         if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) {
1601                 rc = security_transition_sid(sid, dsec->sid, tclass,
1602                                              &dentry->d_name, &newsid);
1603                 if (rc)
1604                         return rc;
1605         }
1606
1607         rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad);
1608         if (rc)
1609                 return rc;
1610
1611         return avc_has_perm(newsid, sbsec->sid,
1612                             SECCLASS_FILESYSTEM,
1613                             FILESYSTEM__ASSOCIATE, &ad);
1614 }
1615
1616 /* Check whether a task can create a key. */
1617 static int may_create_key(u32 ksid,
1618                           struct task_struct *ctx)
1619 {
1620         u32 sid = task_sid(ctx);
1621
1622         return avc_has_perm(sid, ksid, SECCLASS_KEY, KEY__CREATE, NULL);
1623 }
1624
1625 #define MAY_LINK        0
1626 #define MAY_UNLINK      1
1627 #define MAY_RMDIR       2
1628
1629 /* Check whether a task can link, unlink, or rmdir a file/directory. */
1630 static int may_link(struct inode *dir,
1631                     struct dentry *dentry,
1632                     int kind)
1633
1634 {
1635         struct inode_security_struct *dsec, *isec;
1636         struct common_audit_data ad;
1637         u32 sid = current_sid();
1638         u32 av;
1639         int rc;
1640
1641         dsec = dir->i_security;
1642         isec = dentry->d_inode->i_security;
1643
1644         COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
1645         ad.u.dentry = dentry;
1646
1647         av = DIR__SEARCH;
1648         av |= (kind ? DIR__REMOVE_NAME : DIR__ADD_NAME);
1649         rc = avc_has_perm(sid, dsec->sid, SECCLASS_DIR, av, &ad);
1650         if (rc)
1651                 return rc;
1652
1653         switch (kind) {
1654         case MAY_LINK:
1655                 av = FILE__LINK;
1656                 break;
1657         case MAY_UNLINK:
1658                 av = FILE__UNLINK;
1659                 break;
1660         case MAY_RMDIR:
1661                 av = DIR__RMDIR;
1662                 break;
1663         default:
1664                 printk(KERN_WARNING "SELinux: %s:  unrecognized kind %d\n",
1665                         __func__, kind);
1666                 return 0;
1667         }
1668
1669         rc = avc_has_perm(sid, isec->sid, isec->sclass, av, &ad);
1670         return rc;
1671 }
1672
1673 static inline int may_rename(struct inode *old_dir,
1674                              struct dentry *old_dentry,
1675                              struct inode *new_dir,
1676                              struct dentry *new_dentry)
1677 {
1678         struct inode_security_struct *old_dsec, *new_dsec, *old_isec, *new_isec;
1679         struct common_audit_data ad;
1680         u32 sid = current_sid();
1681         u32 av;
1682         int old_is_dir, new_is_dir;
1683         int rc;
1684
1685         old_dsec = old_dir->i_security;
1686         old_isec = old_dentry->d_inode->i_security;
1687         old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
1688         new_dsec = new_dir->i_security;
1689
1690         COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
1691
1692         ad.u.dentry = old_dentry;
1693         rc = avc_has_perm(sid, old_dsec->sid, SECCLASS_DIR,
1694                           DIR__REMOVE_NAME | DIR__SEARCH, &ad);
1695         if (rc)
1696                 return rc;
1697         rc = avc_has_perm(sid, old_isec->sid,
1698                           old_isec->sclass, FILE__RENAME, &ad);
1699         if (rc)
1700                 return rc;
1701         if (old_is_dir && new_dir != old_dir) {
1702                 rc = avc_has_perm(sid, old_isec->sid,
1703                                   old_isec->sclass, DIR__REPARENT, &ad);
1704                 if (rc)
1705                         return rc;
1706         }
1707
1708         ad.u.dentry = new_dentry;
1709         av = DIR__ADD_NAME | DIR__SEARCH;
1710         if (new_dentry->d_inode)
1711                 av |= DIR__REMOVE_NAME;
1712         rc = avc_has_perm(sid, new_dsec->sid, SECCLASS_DIR, av, &ad);
1713         if (rc)
1714                 return rc;
1715         if (new_dentry->d_inode) {
1716                 new_isec = new_dentry->d_inode->i_security;
1717                 new_is_dir = S_ISDIR(new_dentry->d_inode->i_mode);
1718                 rc = avc_has_perm(sid, new_isec->sid,
1719                                   new_isec->sclass,
1720                                   (new_is_dir ? DIR__RMDIR : FILE__UNLINK), &ad);
1721                 if (rc)
1722                         return rc;
1723         }
1724
1725         return 0;
1726 }
1727
1728 /* Check whether a task can perform a filesystem operation. */
1729 static int superblock_has_perm(const struct cred *cred,
1730                                struct super_block *sb,
1731                                u32 perms,
1732                                struct common_audit_data *ad)
1733 {
1734         struct superblock_security_struct *sbsec;
1735         u32 sid = cred_sid(cred);
1736
1737         sbsec = sb->s_security;
1738         return avc_has_perm(sid, sbsec->sid, SECCLASS_FILESYSTEM, perms, ad);
1739 }
1740
1741 /* Convert a Linux mode and permission mask to an access vector. */
1742 static inline u32 file_mask_to_av(int mode, int mask)
1743 {
1744         u32 av = 0;
1745
1746         if ((mode & S_IFMT) != S_IFDIR) {
1747                 if (mask & MAY_EXEC)
1748                         av |= FILE__EXECUTE;
1749                 if (mask & MAY_READ)
1750                         av |= FILE__READ;
1751
1752                 if (mask & MAY_APPEND)
1753                         av |= FILE__APPEND;
1754                 else if (mask & MAY_WRITE)
1755                         av |= FILE__WRITE;
1756
1757         } else {
1758                 if (mask & MAY_EXEC)
1759                         av |= DIR__SEARCH;
1760                 if (mask & MAY_WRITE)
1761                         av |= DIR__WRITE;
1762                 if (mask & MAY_READ)
1763                         av |= DIR__READ;
1764         }
1765
1766         return av;
1767 }
1768
1769 /* Convert a Linux file to an access vector. */
1770 static inline u32 file_to_av(struct file *file)
1771 {
1772         u32 av = 0;
1773
1774         if (file->f_mode & FMODE_READ)
1775                 av |= FILE__READ;
1776         if (file->f_mode & FMODE_WRITE) {
1777                 if (file->f_flags & O_APPEND)
1778                         av |= FILE__APPEND;
1779                 else
1780                         av |= FILE__WRITE;
1781         }
1782         if (!av) {
1783                 /*
1784                  * Special file opened with flags 3 for ioctl-only use.
1785                  */
1786                 av = FILE__IOCTL;
1787         }
1788
1789         return av;
1790 }
1791
1792 /*
1793  * Convert a file to an access vector and include the correct open
1794  * open permission.
1795  */
1796 static inline u32 open_file_to_av(struct file *file)
1797 {
1798         u32 av = file_to_av(file);
1799
1800         if (selinux_policycap_openperm)
1801                 av |= FILE__OPEN;
1802
1803         return av;
1804 }
1805
1806 /* Hook functions begin here. */
1807
1808 static int selinux_ptrace_access_check(struct task_struct *child,
1809                                      unsigned int mode)
1810 {
1811         int rc;
1812
1813         rc = cap_ptrace_access_check(child, mode);
1814         if (rc)
1815                 return rc;
1816
1817         if (mode == PTRACE_MODE_READ) {
1818                 u32 sid = current_sid();
1819                 u32 csid = task_sid(child);
1820                 return avc_has_perm(sid, csid, SECCLASS_FILE, FILE__READ, NULL);
1821         }
1822
1823         return current_has_perm(child, PROCESS__PTRACE);
1824 }
1825
1826 static int selinux_ptrace_traceme(struct task_struct *parent)
1827 {
1828         int rc;
1829
1830         rc = cap_ptrace_traceme(parent);
1831         if (rc)
1832                 return rc;
1833
1834         return task_has_perm(parent, current, PROCESS__PTRACE);
1835 }
1836
1837 static int selinux_capget(struct task_struct *target, kernel_cap_t *effective,
1838                           kernel_cap_t *inheritable, kernel_cap_t *permitted)
1839 {
1840         int error;
1841
1842         error = current_has_perm(target, PROCESS__GETCAP);
1843         if (error)
1844                 return error;
1845
1846         return cap_capget(target, effective, inheritable, permitted);
1847 }
1848
1849 static int selinux_capset(struct cred *new, const struct cred *old,
1850                           const kernel_cap_t *effective,
1851                           const kernel_cap_t *inheritable,
1852                           const kernel_cap_t *permitted)
1853 {
1854         int error;
1855
1856         error = cap_capset(new, old,
1857                                       effective, inheritable, permitted);
1858         if (error)
1859                 return error;
1860
1861         return cred_has_perm(old, new, PROCESS__SETCAP);
1862 }
1863
1864 /*
1865  * (This comment used to live with the selinux_task_setuid hook,
1866  * which was removed).
1867  *
1868  * Since setuid only affects the current process, and since the SELinux
1869  * controls are not based on the Linux identity attributes, SELinux does not
1870  * need to control this operation.  However, SELinux does control the use of
1871  * the CAP_SETUID and CAP_SETGID capabilities using the capable hook.
1872  */
1873
1874 static int selinux_capable(struct task_struct *tsk, const struct cred *cred,
1875                            struct user_namespace *ns, int cap, int audit)
1876 {
1877         int rc;
1878
1879         rc = cap_capable(tsk, cred, ns, cap, audit);
1880         if (rc)
1881                 return rc;
1882
1883         return task_has_capability(tsk, cred, cap, audit);
1884 }
1885
1886 static int selinux_quotactl(int cmds, int type, int id, struct super_block *sb)
1887 {
1888         const struct cred *cred = current_cred();
1889         int rc = 0;
1890
1891         if (!sb)
1892                 return 0;
1893
1894         switch (cmds) {
1895         case Q_SYNC:
1896         case Q_QUOTAON:
1897         case Q_QUOTAOFF:
1898         case Q_SETINFO:
1899         case Q_SETQUOTA:
1900                 rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAMOD, NULL);
1901                 break;
1902         case Q_GETFMT:
1903         case Q_GETINFO:
1904         case Q_GETQUOTA:
1905                 rc = superblock_has_perm(cred, sb, FILESYSTEM__QUOTAGET, NULL);
1906                 break;
1907         default:
1908                 rc = 0;  /* let the kernel handle invalid cmds */
1909                 break;
1910         }
1911         return rc;
1912 }
1913
1914 static int selinux_quota_on(struct dentry *dentry)
1915 {
1916         const struct cred *cred = current_cred();
1917
1918         return dentry_has_perm(cred, dentry, FILE__QUOTAON);
1919 }
1920
1921 static int selinux_syslog(int type)
1922 {
1923         int rc;
1924
1925         switch (type) {
1926         case SYSLOG_ACTION_READ_ALL:    /* Read last kernel messages */
1927         case SYSLOG_ACTION_SIZE_BUFFER: /* Return size of the log buffer */
1928                 rc = task_has_system(current, SYSTEM__SYSLOG_READ);
1929                 break;
1930         case SYSLOG_ACTION_CONSOLE_OFF: /* Disable logging to console */
1931         case SYSLOG_ACTION_CONSOLE_ON:  /* Enable logging to console */
1932         /* Set level of messages printed to console */
1933         case SYSLOG_ACTION_CONSOLE_LEVEL:
1934                 rc = task_has_system(current, SYSTEM__SYSLOG_CONSOLE);
1935                 break;
1936         case SYSLOG_ACTION_CLOSE:       /* Close log */
1937         case SYSLOG_ACTION_OPEN:        /* Open log */
1938         case SYSLOG_ACTION_READ:        /* Read from log */
1939         case SYSLOG_ACTION_READ_CLEAR:  /* Read/clear last kernel messages */
1940         case SYSLOG_ACTION_CLEAR:       /* Clear ring buffer */
1941         default:
1942                 rc = task_has_system(current, SYSTEM__SYSLOG_MOD);
1943                 break;
1944         }
1945         return rc;
1946 }
1947
1948 /*
1949  * Check that a process has enough memory to allocate a new virtual
1950  * mapping. 0 means there is enough memory for the allocation to
1951  * succeed and -ENOMEM implies there is not.
1952  *
1953  * Do not audit the selinux permission check, as this is applied to all
1954  * processes that allocate mappings.
1955  */
1956 static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
1957 {
1958         int rc, cap_sys_admin = 0;
1959
1960         rc = selinux_capable(current, current_cred(),
1961                              &init_user_ns, CAP_SYS_ADMIN,
1962                              SECURITY_CAP_NOAUDIT);
1963         if (rc == 0)
1964                 cap_sys_admin = 1;
1965
1966         return __vm_enough_memory(mm, pages, cap_sys_admin);
1967 }
1968
1969 /* binprm security operations */
1970
1971 static int selinux_bprm_set_creds(struct linux_binprm *bprm)
1972 {
1973         const struct task_security_struct *old_tsec;
1974         struct task_security_struct *new_tsec;
1975         struct inode_security_struct *isec;
1976         struct common_audit_data ad;
1977         struct inode *inode = bprm->file->f_path.dentry->d_inode;
1978         int rc;
1979
1980         rc = cap_bprm_set_creds(bprm);
1981         if (rc)
1982                 return rc;
1983
1984         /* SELinux context only depends on initial program or script and not
1985          * the script interpreter */
1986         if (bprm->cred_prepared)
1987                 return 0;
1988
1989         old_tsec = current_security();
1990         new_tsec = bprm->cred->security;
1991         isec = inode->i_security;
1992
1993         /* Default to the current task SID. */
1994         new_tsec->sid = old_tsec->sid;
1995         new_tsec->osid = old_tsec->sid;
1996
1997         /* Reset fs, key, and sock SIDs on execve. */
1998         new_tsec->create_sid = 0;
1999         new_tsec->keycreate_sid = 0;
2000         new_tsec->sockcreate_sid = 0;
2001
2002         if (old_tsec->exec_sid) {
2003                 new_tsec->sid = old_tsec->exec_sid;
2004                 /* Reset exec SID on execve. */
2005                 new_tsec->exec_sid = 0;
2006         } else {
2007                 /* Check for a default transition on this program. */
2008                 rc = security_transition_sid(old_tsec->sid, isec->sid,
2009                                              SECCLASS_PROCESS, NULL,
2010                                              &new_tsec->sid);
2011                 if (rc)
2012                         return rc;
2013         }
2014
2015         COMMON_AUDIT_DATA_INIT(&ad, PATH);
2016         ad.u.path = bprm->file->f_path;
2017
2018         if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)
2019                 new_tsec->sid = old_tsec->sid;
2020
2021         if (new_tsec->sid == old_tsec->sid) {
2022                 rc = avc_has_perm(old_tsec->sid, isec->sid,
2023                                   SECCLASS_FILE, FILE__EXECUTE_NO_TRANS, &ad);
2024                 if (rc)
2025                         return rc;
2026         } else {
2027                 /* Check permissions for the transition. */
2028                 rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
2029                                   SECCLASS_PROCESS, PROCESS__TRANSITION, &ad);
2030                 if (rc)
2031                         return rc;
2032
2033                 rc = avc_has_perm(new_tsec->sid, isec->sid,
2034                                   SECCLASS_FILE, FILE__ENTRYPOINT, &ad);
2035                 if (rc)
2036                         return rc;
2037
2038                 /* Check for shared state */
2039                 if (bprm->unsafe & LSM_UNSAFE_SHARE) {
2040                         rc = avc_has_perm(old_tsec->sid, new_tsec->sid,
2041                                           SECCLASS_PROCESS, PROCESS__SHARE,
2042                                           NULL);
2043                         if (rc)
2044                                 return -EPERM;
2045                 }
2046
2047                 /* Make sure that anyone attempting to ptrace over a task that
2048                  * changes its SID has the appropriate permit */
2049                 if (bprm->unsafe &
2050                     (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
2051                         struct task_struct *tracer;
2052                         struct task_security_struct *sec;
2053                         u32 ptsid = 0;
2054
2055                         rcu_read_lock();
2056                         tracer = ptrace_parent(current);
2057                         if (likely(tracer != NULL)) {
2058                                 sec = __task_cred(tracer)->security;
2059                                 ptsid = sec->sid;
2060                         }
2061                         rcu_read_unlock();
2062
2063                         if (ptsid != 0) {
2064                                 rc = avc_has_perm(ptsid, new_tsec->sid,
2065                                                   SECCLASS_PROCESS,
2066                                                   PROCESS__PTRACE, NULL);
2067                                 if (rc)
2068                                         return -EPERM;
2069                         }
2070                 }
2071
2072                 /* Clear any possibly unsafe personality bits on exec: */
2073                 bprm->per_clear |= PER_CLEAR_ON_SETID;
2074         }
2075
2076         return 0;
2077 }
2078
2079 static int selinux_bprm_secureexec(struct linux_binprm *bprm)
2080 {
2081         const struct task_security_struct *tsec = current_security();
2082         u32 sid, osid;
2083         int atsecure = 0;
2084
2085         sid = tsec->sid;
2086         osid = tsec->osid;
2087
2088         if (osid != sid) {
2089                 /* Enable secure mode for SIDs transitions unless
2090                    the noatsecure permission is granted between
2091                    the two SIDs, i.e. ahp returns 0. */
2092                 atsecure = avc_has_perm(osid, sid,
2093                                         SECCLASS_PROCESS,
2094                                         PROCESS__NOATSECURE, NULL);
2095         }
2096
2097         return (atsecure || cap_bprm_secureexec(bprm));
2098 }
2099
2100 extern struct vfsmount *selinuxfs_mount;
2101 extern struct dentry *selinux_null;
2102
2103 /* Derived from fs/exec.c:flush_old_files. */
2104 static inline void flush_unauthorized_files(const struct cred *cred,
2105                                             struct files_struct *files)
2106 {
2107         struct common_audit_data ad;
2108         struct file *file, *devnull = NULL;
2109         struct tty_struct *tty;
2110         struct fdtable *fdt;
2111         long j = -1;
2112         int drop_tty = 0;
2113
2114         tty = get_current_tty();
2115         if (tty) {
2116                 spin_lock(&tty_files_lock);
2117                 if (!list_empty(&tty->tty_files)) {
2118                         struct tty_file_private *file_priv;
2119                         struct inode *inode;
2120
2121                         /* Revalidate access to controlling tty.
2122                            Use inode_has_perm on the tty inode directly rather
2123                            than using file_has_perm, as this particular open
2124                            file may belong to another process and we are only
2125                            interested in the inode-based check here. */
2126                         file_priv = list_first_entry(&tty->tty_files,
2127                                                 struct tty_file_private, list);
2128                         file = file_priv->file;
2129                         inode = file->f_path.dentry->d_inode;
2130                         if (inode_has_perm_noadp(cred, inode,
2131                                            FILE__READ | FILE__WRITE, 0)) {
2132                                 drop_tty = 1;
2133                         }
2134                 }
2135                 spin_unlock(&tty_files_lock);
2136                 tty_kref_put(tty);
2137         }
2138         /* Reset controlling tty. */
2139         if (drop_tty)
2140                 no_tty();
2141
2142         /* Revalidate access to inherited open files. */
2143
2144         COMMON_AUDIT_DATA_INIT(&ad, INODE);
2145
2146         spin_lock(&files->file_lock);
2147         for (;;) {
2148                 unsigned long set, i;
2149                 int fd;
2150
2151                 j++;
2152                 i = j * __NFDBITS;
2153                 fdt = files_fdtable(files);
2154                 if (i >= fdt->max_fds)
2155                         break;
2156                 set = fdt->open_fds->fds_bits[j];
2157                 if (!set)
2158                         continue;
2159                 spin_unlock(&files->file_lock);
2160                 for ( ; set ; i++, set >>= 1) {
2161                         if (set & 1) {
2162                                 file = fget(i);
2163                                 if (!file)
2164                                         continue;
2165                                 if (file_has_perm(cred,
2166                                                   file,
2167                                                   file_to_av(file))) {
2168                                         sys_close(i);
2169                                         fd = get_unused_fd();
2170                                         if (fd != i) {
2171                                                 if (fd >= 0)
2172                                                         put_unused_fd(fd);
2173                                                 fput(file);
2174                                                 continue;
2175                                         }
2176                                         if (devnull) {
2177                                                 get_file(devnull);
2178                                         } else {
2179                                                 devnull = dentry_open(
2180                                                         dget(selinux_null),
2181                                                         mntget(selinuxfs_mount),
2182                                                         O_RDWR, cred);
2183                                                 if (IS_ERR(devnull)) {
2184                                                         devnull = NULL;
2185                                                         put_unused_fd(fd);
2186                                                         fput(file);
2187                                                         continue;
2188                                                 }
2189                                         }
2190                                         fd_install(fd, devnull);
2191                                 }
2192                                 fput(file);
2193                         }
2194                 }
2195                 spin_lock(&files->file_lock);
2196
2197         }
2198         spin_unlock(&files->file_lock);
2199 }
2200
2201 /*
2202  * Prepare a process for imminent new credential changes due to exec
2203  */
2204 static void selinux_bprm_committing_creds(struct linux_binprm *bprm)
2205 {
2206         struct task_security_struct *new_tsec;
2207         struct rlimit *rlim, *initrlim;
2208         int rc, i;
2209
2210         new_tsec = bprm->cred->security;
2211         if (new_tsec->sid == new_tsec->osid)
2212                 return;
2213
2214         /* Close files for which the new task SID is not authorized. */
2215         flush_unauthorized_files(bprm->cred, current->files);
2216
2217         /* Always clear parent death signal on SID transitions. */
2218         current->pdeath_signal = 0;
2219
2220         /* Check whether the new SID can inherit resource limits from the old
2221          * SID.  If not, reset all soft limits to the lower of the current
2222          * task's hard limit and the init task's soft limit.
2223          *
2224          * Note that the setting of hard limits (even to lower them) can be
2225          * controlled by the setrlimit check.  The inclusion of the init task's
2226          * soft limit into the computation is to avoid resetting soft limits
2227          * higher than the default soft limit for cases where the default is
2228          * lower than the hard limit, e.g. RLIMIT_CORE or RLIMIT_STACK.
2229          */
2230         rc = avc_has_perm(new_tsec->osid, new_tsec->sid, SECCLASS_PROCESS,
2231                           PROCESS__RLIMITINH, NULL);
2232         if (rc) {
2233                 /* protect against do_prlimit() */
2234                 task_lock(current);
2235                 for (i = 0; i < RLIM_NLIMITS; i++) {
2236                         rlim = current->signal->rlim + i;
2237                         initrlim = init_task.signal->rlim + i;
2238                         rlim->rlim_cur = min(rlim->rlim_max, initrlim->rlim_cur);
2239                 }
2240                 task_unlock(current);
2241                 update_rlimit_cpu(current, rlimit(RLIMIT_CPU));
2242         }
2243 }
2244
2245 /*
2246  * Clean up the process immediately after the installation of new credentials
2247  * due to exec
2248  */
2249 static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
2250 {
2251         const struct task_security_struct *tsec = current_security();
2252         struct itimerval itimer;
2253         u32 osid, sid;
2254         int rc, i;
2255
2256         osid = tsec->osid;
2257         sid = tsec->sid;
2258
2259         if (sid == osid)
2260                 return;
2261
2262         /* Check whether the new SID can inherit signal state from the old SID.
2263          * If not, clear itimers to avoid subsequent signal generation and
2264          * flush and unblock signals.
2265          *
2266          * This must occur _after_ the task SID has been updated so that any
2267          * kill done after the flush will be checked against the new SID.
2268          */
2269         rc = avc_has_perm(osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL);
2270         if (rc) {
2271                 memset(&itimer, 0, sizeof itimer);
2272                 for (i = 0; i < 3; i++)
2273                         do_setitimer(i, &itimer, NULL);
2274                 spin_lock_irq(&current->sighand->siglock);
2275                 if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
2276                         __flush_signals(current);
2277                         flush_signal_handlers(current, 1);
2278                         sigemptyset(&current->blocked);
2279                 }
2280                 spin_unlock_irq(&current->sighand->siglock);
2281         }
2282
2283         /* Wake up the parent if it is waiting so that it can recheck
2284          * wait permission to the new task SID. */
2285         read_lock(&tasklist_lock);
2286         __wake_up_parent(current, current->real_parent);
2287         read_unlock(&tasklist_lock);
2288 }
2289
2290 /* superblock security operations */
2291
2292 static int selinux_sb_alloc_security(struct super_block *sb)
2293 {
2294         return superblock_alloc_security(sb);
2295 }
2296
2297 static void selinux_sb_free_security(struct super_block *sb)
2298 {
2299         superblock_free_security(sb);
2300 }
2301
2302 static inline int match_prefix(char *prefix, int plen, char *option, int olen)
2303 {
2304         if (plen > olen)
2305                 return 0;
2306
2307         return !memcmp(prefix, option, plen);
2308 }
2309
2310 static inline int selinux_option(char *option, int len)
2311 {
2312         return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
2313                 match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
2314                 match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
2315                 match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len) ||
2316                 match_prefix(LABELSUPP_STR, sizeof(LABELSUPP_STR)-1, option, len));
2317 }
2318
2319 static inline void take_option(char **to, char *from, int *first, int len)
2320 {
2321         if (!*first) {
2322                 **to = ',';
2323                 *to += 1;
2324         } else
2325                 *first = 0;
2326         memcpy(*to, from, len);
2327         *to += len;
2328 }
2329
2330 static inline void take_selinux_option(char **to, char *from, int *first,
2331                                        int len)
2332 {
2333         int current_size = 0;
2334
2335         if (!*first) {
2336                 **to = '|';
2337                 *to += 1;
2338         } else
2339                 *first = 0;
2340
2341         while (current_size < len) {
2342                 if (*from != '"') {
2343                         **to = *from;
2344                         *to += 1;
2345                 }
2346                 from += 1;
2347                 current_size += 1;
2348         }
2349 }
2350
2351 static int selinux_sb_copy_data(char *orig, char *copy)
2352 {
2353         int fnosec, fsec, rc = 0;
2354         char *in_save, *in_curr, *in_end;
2355         char *sec_curr, *nosec_save, *nosec;
2356         int open_quote = 0;
2357
2358         in_curr = orig;
2359         sec_curr = copy;
2360
2361         nosec = (char *)get_zeroed_page(GFP_KERNEL);
2362         if (!nosec) {
2363                 rc = -ENOMEM;
2364                 goto out;
2365         }
2366
2367         nosec_save = nosec;
2368         fnosec = fsec = 1;
2369         in_save = in_end = orig;
2370
2371         do {
2372                 if (*in_end == '"')
2373                         open_quote = !open_quote;
2374                 if ((*in_end == ',' && open_quote == 0) ||
2375                                 *in_end == '\0') {
2376                         int len = in_end - in_curr;
2377
2378                         if (selinux_option(in_curr, len))
2379                                 take_selinux_option(&sec_curr, in_curr, &fsec, len);
2380                         else
2381                                 take_option(&nosec, in_curr, &fnosec, len);
2382
2383                         in_curr = in_end + 1;
2384                 }
2385         } while (*in_end++);
2386
2387         strcpy(in_save, nosec_save);
2388         free_page((unsigned long)nosec_save);
2389 out:
2390         return rc;
2391 }
2392
2393 static int selinux_sb_remount(struct super_block *sb, void *data)
2394 {
2395         int rc, i, *flags;
2396         struct security_mnt_opts opts;
2397         char *secdata, **mount_options;
2398         struct superblock_security_struct *sbsec = sb->s_security;
2399
2400         if (!(sbsec->flags & SE_SBINITIALIZED))
2401                 return 0;
2402
2403         if (!data)
2404                 return 0;
2405
2406         if (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
2407                 return 0;
2408
2409         security_init_mnt_opts(&opts);
2410         secdata = alloc_secdata();
2411         if (!secdata)
2412                 return -ENOMEM;
2413         rc = selinux_sb_copy_data(data, secdata);
2414         if (rc)
2415                 goto out_free_secdata;
2416
2417         rc = selinux_parse_opts_str(secdata, &opts);
2418         if (rc)
2419                 goto out_free_secdata;
2420
2421         mount_options = opts.mnt_opts;
2422         flags = opts.mnt_opts_flags;
2423
2424         for (i = 0; i < opts.num_mnt_opts; i++) {
2425                 u32 sid;
2426                 size_t len;
2427
2428                 if (flags[i] == SE_SBLABELSUPP)
2429                         continue;
2430                 len = strlen(mount_options[i]);
2431                 rc = security_context_to_sid(mount_options[i], len, &sid);
2432                 if (rc) {
2433                         printk(KERN_WARNING "SELinux: security_context_to_sid"
2434                                "(%s) failed for (dev %s, type %s) errno=%d\n",
2435                                mount_options[i], sb->s_id, sb->s_type->name, rc);
2436                         goto out_free_opts;
2437                 }
2438                 rc = -EINVAL;
2439                 switch (flags[i]) {
2440                 case FSCONTEXT_MNT:
2441                         if (bad_option(sbsec, FSCONTEXT_MNT, sbsec->sid, sid))
2442                                 goto out_bad_option;
2443                         break;
2444                 case CONTEXT_MNT:
2445                         if (bad_option(sbsec, CONTEXT_MNT, sbsec->mntpoint_sid, sid))
2446                                 goto out_bad_option;
2447                         break;
2448                 case ROOTCONTEXT_MNT: {
2449                         struct inode_security_struct *root_isec;
2450                         root_isec = sb->s_root->d_inode->i_security;
2451
2452                         if (bad_option(sbsec, ROOTCONTEXT_MNT, root_isec->sid, sid))
2453                                 goto out_bad_option;
2454                         break;
2455                 }
2456                 case DEFCONTEXT_MNT:
2457                         if (bad_option(sbsec, DEFCONTEXT_MNT, sbsec->def_sid, sid))
2458                                 goto out_bad_option;
2459                         break;
2460                 default:
2461                         goto out_free_opts;
2462                 }
2463         }
2464
2465         rc = 0;
2466 out_free_opts:
2467         security_free_mnt_opts(&opts);
2468 out_free_secdata:
2469         free_secdata(secdata);
2470         return rc;
2471 out_bad_option:
2472         printk(KERN_WARNING "SELinux: unable to change security options "
2473                "during remount (dev %s, type=%s)\n", sb->s_id,
2474                sb->s_type->name);
2475         goto out_free_opts;
2476 }
2477
2478 static int selinux_sb_kern_mount(struct super_block *sb, int flags, void *data)
2479 {
2480         const struct cred *cred = current_cred();
2481         struct common_audit_data ad;
2482         int rc;
2483
2484         rc = superblock_doinit(sb, data);
2485         if (rc)
2486                 return rc;
2487
2488         /* Allow all mounts performed by the kernel */
2489         if (flags & MS_KERNMOUNT)
2490                 return 0;
2491
2492         COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
2493         ad.u.dentry = sb->s_root;
2494         return superblock_has_perm(cred, sb, FILESYSTEM__MOUNT, &ad);
2495 }
2496
2497 static int selinux_sb_statfs(struct dentry *dentry)
2498 {
2499         const struct cred *cred = current_cred();
2500         struct common_audit_data ad;
2501
2502         COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
2503         ad.u.dentry = dentry->d_sb->s_root;
2504         return superblock_has_perm(cred, dentry->d_sb, FILESYSTEM__GETATTR, &ad);
2505 }
2506
2507 static int selinux_mount(char *dev_name,
2508                          struct path *path,
2509                          char *type,
2510                          unsigned long flags,
2511                          void *data)
2512 {
2513         const struct cred *cred = current_cred();
2514
2515         if (flags & MS_REMOUNT)
2516                 return superblock_has_perm(cred, path->mnt->mnt_sb,
2517                                            FILESYSTEM__REMOUNT, NULL);
2518         else
2519                 return path_has_perm(cred, path, FILE__MOUNTON);
2520 }
2521
2522 static int selinux_umount(struct vfsmount *mnt, int flags)
2523 {
2524         const struct cred *cred = current_cred();
2525
2526         return superblock_has_perm(cred, mnt->mnt_sb,
2527                                    FILESYSTEM__UNMOUNT, NULL);
2528 }
2529
2530 /* inode security operations */
2531
2532 static int selinux_inode_alloc_security(struct inode *inode)
2533 {
2534         return inode_alloc_security(inode);
2535 }
2536
2537 static void selinux_inode_free_security(struct inode *inode)
2538 {
2539         inode_free_security(inode);
2540 }
2541
2542 static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
2543                                        const struct qstr *qstr, char **name,
2544                                        void **value, size_t *len)
2545 {
2546         const struct task_security_struct *tsec = current_security();
2547         struct inode_security_struct *dsec;
2548         struct superblock_security_struct *sbsec;
2549         u32 sid, newsid, clen;
2550         int rc;
2551         char *namep = NULL, *context;
2552
2553         dsec = dir->i_security;
2554         sbsec = dir->i_sb->s_security;
2555
2556         sid = tsec->sid;
2557         newsid = tsec->create_sid;
2558
2559         if ((sbsec->flags & SE_SBINITIALIZED) &&
2560             (sbsec->behavior == SECURITY_FS_USE_MNTPOINT))
2561                 newsid = sbsec->mntpoint_sid;
2562         else if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) {
2563                 rc = security_transition_sid(sid, dsec->sid,
2564                                              inode_mode_to_security_class(inode->i_mode),
2565                                              qstr, &newsid);
2566                 if (rc) {
2567                         printk(KERN_WARNING "%s:  "
2568                                "security_transition_sid failed, rc=%d (dev=%s "
2569                                "ino=%ld)\n",
2570                                __func__,
2571                                -rc, inode->i_sb->s_id, inode->i_ino);
2572                         return rc;
2573                 }
2574         }
2575
2576         /* Possibly defer initialization to selinux_complete_init. */
2577         if (sbsec->flags & SE_SBINITIALIZED) {
2578                 struct inode_security_struct *isec = inode->i_security;
2579                 isec->sclass = inode_mode_to_security_class(inode->i_mode);
2580                 isec->sid = newsid;
2581                 isec->initialized = 1;
2582         }
2583
2584         if (!ss_initialized || !(sbsec->flags & SE_SBLABELSUPP))
2585                 return -EOPNOTSUPP;
2586
2587         if (name) {
2588                 namep = kstrdup(XATTR_SELINUX_SUFFIX, GFP_NOFS);
2589                 if (!namep)
2590                         return -ENOMEM;
2591                 *name = namep;
2592         }
2593
2594         if (value && len) {
2595                 rc = security_sid_to_context_force(newsid, &context, &clen);
2596                 if (rc) {
2597                         kfree(namep);
2598                         return rc;
2599                 }
2600                 *value = context;
2601                 *len = clen;
2602         }
2603
2604         return 0;
2605 }
2606
2607 static int selinux_inode_create(struct inode *dir, struct dentry *dentry, int mask)
2608 {
2609         return may_create(dir, dentry, SECCLASS_FILE);
2610 }
2611
2612 static int selinux_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
2613 {
2614         return may_link(dir, old_dentry, MAY_LINK);
2615 }
2616
2617 static int selinux_inode_unlink(struct inode *dir, struct dentry *dentry)
2618 {
2619         return may_link(dir, dentry, MAY_UNLINK);
2620 }
2621
2622 static int selinux_inode_symlink(struct inode *dir, struct dentry *dentry, const char *name)
2623 {
2624         return may_create(dir, dentry, SECCLASS_LNK_FILE);
2625 }
2626
2627 static int selinux_inode_mkdir(struct inode *dir, struct dentry *dentry, int mask)
2628 {
2629         return may_create(dir, dentry, SECCLASS_DIR);
2630 }
2631
2632 static int selinux_inode_rmdir(struct inode *dir, struct dentry *dentry)
2633 {
2634         return may_link(dir, dentry, MAY_RMDIR);
2635 }
2636
2637 static int selinux_inode_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
2638 {
2639         return may_create(dir, dentry, inode_mode_to_security_class(mode));
2640 }
2641
2642 static int selinux_inode_rename(struct inode *old_inode, struct dentry *old_dentry,
2643                                 struct inode *new_inode, struct dentry *new_dentry)
2644 {
2645         return may_rename(old_inode, old_dentry, new_inode, new_dentry);
2646 }
2647
2648 static int selinux_inode_readlink(struct dentry *dentry)
2649 {
2650         const struct cred *cred = current_cred();
2651
2652         return dentry_has_perm(cred, dentry, FILE__READ);
2653 }
2654
2655 static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *nameidata)
2656 {
2657         const struct cred *cred = current_cred();
2658
2659         return dentry_has_perm(cred, dentry, FILE__READ);
2660 }
2661
2662 static int selinux_inode_permission(struct inode *inode, int mask)
2663 {
2664         const struct cred *cred = current_cred();
2665         struct common_audit_data ad;
2666         u32 perms;
2667         bool from_access;
2668         unsigned flags = mask & MAY_NOT_BLOCK;
2669
2670         from_access = mask & MAY_ACCESS;
2671         mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
2672
2673         /* No permission to check.  Existence test. */
2674         if (!mask)
2675                 return 0;
2676
2677         COMMON_AUDIT_DATA_INIT(&ad, INODE);
2678         ad.u.inode = inode;
2679
2680         if (from_access)
2681                 ad.selinux_audit_data.auditdeny |= FILE__AUDIT_ACCESS;
2682
2683         perms = file_mask_to_av(inode->i_mode, mask);
2684
2685         return inode_has_perm(cred, inode, perms, &ad, flags);
2686 }
2687
2688 static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
2689 {
2690         const struct cred *cred = current_cred();
2691         unsigned int ia_valid = iattr->ia_valid;
2692
2693         /* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */
2694         if (ia_valid & ATTR_FORCE) {
2695                 ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE |
2696                               ATTR_FORCE);
2697                 if (!ia_valid)
2698                         return 0;
2699         }
2700
2701         if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID |
2702                         ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET))
2703                 return dentry_has_perm(cred, dentry, FILE__SETATTR);
2704
2705         return dentry_has_perm(cred, dentry, FILE__WRITE);
2706 }
2707
2708 static int selinux_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
2709 {
2710         const struct cred *cred = current_cred();
2711         struct path path;
2712
2713         path.dentry = dentry;
2714         path.mnt = mnt;
2715
2716         return path_has_perm(cred, &path, FILE__GETATTR);
2717 }
2718
2719 static int selinux_inode_setotherxattr(struct dentry *dentry, const char *name)
2720 {
2721         const struct cred *cred = current_cred();
2722
2723         if (!strncmp(name, XATTR_SECURITY_PREFIX,
2724                      sizeof XATTR_SECURITY_PREFIX - 1)) {
2725                 if (!strcmp(name, XATTR_NAME_CAPS)) {
2726                         if (!capable(CAP_SETFCAP))
2727                                 return -EPERM;
2728                 } else if (!capable(CAP_SYS_ADMIN)) {
2729                         /* A different attribute in the security namespace.
2730                            Restrict to administrator. */
2731                         return -EPERM;
2732                 }
2733         }
2734
2735         /* Not an attribute we recognize, so just check the
2736            ordinary setattr permission. */
2737         return dentry_has_perm(cred, dentry, FILE__SETATTR);
2738 }
2739
2740 static int selinux_inode_setxattr(struct dentry *dentry, const char *name,
2741                                   const void *value, size_t size, int flags)
2742 {
2743         struct inode *inode = dentry->d_inode;
2744         struct inode_security_struct *isec = inode->i_security;
2745         struct superblock_security_struct *sbsec;
2746         struct common_audit_data ad;
2747         u32 newsid, sid = current_sid();
2748         int rc = 0;
2749
2750         if (strcmp(name, XATTR_NAME_SELINUX))
2751                 return selinux_inode_setotherxattr(dentry, name);
2752
2753         sbsec = inode->i_sb->s_security;
2754         if (!(sbsec->flags & SE_SBLABELSUPP))
2755                 return -EOPNOTSUPP;
2756
2757         if (!inode_owner_or_capable(inode))
2758                 return -EPERM;
2759
2760         COMMON_AUDIT_DATA_INIT(&ad, DENTRY);
2761         ad.u.dentry = dentry;
2762
2763         rc = avc_has_perm(sid, isec->sid, isec->sclass,
2764                           FILE__RELABELFROM, &ad);
2765         if (rc)
2766                 return rc;
2767
2768         rc = security_context_to_sid(value, size, &newsid);
2769         if (rc == -EINVAL) {
2770                 if (!capable(CAP_MAC_ADMIN))
2771                         return rc;
2772                 rc = security_context_to_sid_force(value, size, &newsid);
2773         }
2774         if (rc)
2775                 return rc;
2776
2777         rc = avc_has_perm(sid, newsid, isec->sclass,
2778                           FILE__RELABELTO, &ad);
2779         if (rc)
2780                 return rc;
2781
2782         rc = security_validate_transition(isec->sid, newsid, sid,
2783                                           isec->sclass);
2784         if (rc)
2785                 return rc;
2786
2787         return avc_has_perm(newsid,
2788                             sbsec->sid,
2789                             SECCLASS_FILESYSTEM,
2790                             FILESYSTEM__ASSOCIATE,
2791                             &ad);
2792 }
2793
2794 static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name,
2795                                         const void *value, size_t size,
2796                                         int flags)
2797 {
2798         struct inode *inode = dentry->d_inode;
2799         struct inode_security_struct *isec = inode->i_security;
2800         u32 newsid;
2801         int rc;
2802
2803         if (strcmp(name, XATTR_NAME_SELINUX)) {
2804                 /* Not an attribute we recognize, so nothing to do. */
2805                 return;
2806         }
2807
2808         rc = security_context_to_sid_force(value, size, &newsid);
2809         if (rc) {
2810                 printk(KERN_ERR "SELinux:  unable to map context to SID"
2811                        "for (%s, %lu), rc=%d\n",
2812                        inode->i_sb->s_id, inode->i_ino, -rc);
2813                 return;
2814         }
2815
2816         isec->sid = newsid;
2817         return;
2818 }
2819
2820 static int selinux_inode_getxattr(struct dentry *dentry, const char *name)
2821 {
2822         const struct cred *cred = current_cred();
2823
2824         return dentry_has_perm(cred, dentry, FILE__GETATTR);
2825 }
2826
2827 static int selinux_inode_listxattr(struct dentry *dentry)
2828 {
2829         const struct cred *cred = current_cred();
2830
2831         return dentry_has_perm(cred, dentry, FILE__GETATTR);
2832 }
2833
2834 static int selinux_inode_removexattr(struct dentry *dentry, const char *name)
2835 {
2836         if (strcmp(name, XATTR_NAME_SELINUX))
2837                 return selinux_inode_setotherxattr(dentry, name);
2838
2839         /* No one is allowed to remove a SELinux security label.
2840            You can change the label, but all data must be labeled. */
2841         return -EACCES;
2842 }
2843
2844 /*
2845  * Copy the inode security context value to the user.
2846  *
2847  * Permission check is handled by selinux_inode_getxattr hook.
2848  */
2849 static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc)
2850 {
2851         u32 size;
2852         int error;
2853         char *context = NULL;
2854         struct inode_security_struct *isec = inode->i_security;
2855
2856         if (strcmp(name, XATTR_SELINUX_SUFFIX))
2857                 return -EOPNOTSUPP;
2858
2859         /*
2860          * If the caller has CAP_MAC_ADMIN, then get the raw context
2861          * value even if it is not defined by current policy; otherwise,
2862          * use the in-core value under current policy.
2863          * Use the non-auditing forms of the permission checks since
2864          * getxattr may be called by unprivileged processes commonly
2865          * and lack of permission just means that we fall back to the
2866          * in-core context value, not a denial.
2867          */
2868         error = selinux_capable(current, current_cred(),
2869                                 &init_user_ns, CAP_MAC_ADMIN,
2870                                 SECURITY_CAP_NOAUDIT);
2871         if (!error)
2872                 error = security_sid_to_context_force(isec->sid, &context,
2873                                                       &size);
2874         else
2875                 error = security_sid_to_context(isec->sid, &context, &size);
2876         if (error)
2877                 return error;
2878         error = size;
2879         if (alloc) {
2880                 *buffer = context;
2881                 goto out_nofree;
2882         }
2883         kfree(context);
2884 out_nofree:
2885         return error;
2886 }
2887
2888 static int selinux_inode_setsecurity(struct inode *inode, const char *name,
2889                                      const void *value, size_t size, int flags)
2890 {
2891         struct inode_security_struct *isec = inode->i_security;
2892         u32 newsid;
2893         int rc;
2894
2895         if (strcmp(name, XATTR_SELINUX_SUFFIX))
2896                 return -EOPNOTSUPP;
2897
2898         if (!value || !size)
2899                 return -EACCES;
2900
2901         rc = security_context_to_sid((void *)value, size, &newsid);
2902         if (rc)
2903                 return rc;
2904
2905         isec->sid = newsid;
2906         isec->initialized = 1;
2907         return 0;
2908 }
2909
2910 static int selinux_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)
2911 {
2912         const int len = sizeof(XATTR_NAME_SELINUX);
2913         if (buffer && len <= buffer_size)
2914                 memcpy(buffer, XATTR_NAME_SELINUX, len);
2915         return len;
2916 }
2917
2918 static void selinux_inode_getsecid(const struct inode *inode, u32 *secid)
2919 {
2920         struct inode_security_struct *isec = inode->i_security;
2921         *secid = isec->sid;
2922 }
2923
2924 /* file security operations */
2925
2926 static int selinux_revalidate_file_permission(struct file *file, int mask)
2927 {
2928         const struct cred *cred = current_cred();
2929         struct inode *inode = file->f_path.dentry->d_inode;
2930
2931         /* file_mask_to_av won't add FILE__WRITE if MAY_APPEND is set */
2932         if ((file->f_flags & O_APPEND) && (mask & MAY_WRITE))
2933                 mask |= MAY_APPEND;
2934
2935         return file_has_perm(cred, file,
2936                              file_mask_to_av(inode->i_mode, mask));
2937 }
2938
2939 static int selinux_file_permission(struct file *file, int mask)
2940 {
2941         struct inode *inode = file->f_path.dentry->d_inode;
2942         struct file_security_struct *fsec = file->f_security;
2943         struct inode_security_struct *isec = inode->i_security;
2944         u32 sid = current_sid();
2945
2946         if (!mask)
2947                 /* No permission to check.  Existence test. */
2948                 return 0;
2949
2950         if (sid == fsec->sid && fsec->isid == isec->sid &&
2951             fsec->pseqno == avc_policy_seqno())
2952                 /* No change since dentry_open check. */
2953                 return 0;
2954
2955         return selinux_revalidate_file_permission(file, mask);
2956 }
2957
2958 static int selinux_file_alloc_security(struct file *file)
2959 {
2960         return file_alloc_security(file);
2961 }
2962
2963 static void selinux_file_free_security(struct file *file)
2964 {
2965         file_free_security(file);
2966 }
2967
2968 static int selinux_file_ioctl(struct file *file, unsigned int cmd,
2969                               unsigned long arg)
2970 {
2971         const struct cred *cred = current_cred();
2972         int error = 0;
2973
2974         switch (cmd) {
2975         case FIONREAD:
2976         /* fall through */
2977         case FIBMAP:
2978         /* fall through */
2979         case FIGETBSZ:
2980         /* fall through */
2981         case EXT2_IOC_GETFLAGS:
2982         /* fall through */
2983         case EXT2_IOC_GETVERSION:
2984                 error = file_has_perm(cred, file, FILE__GETATTR);
2985                 break;
2986
2987         case EXT2_IOC_SETFLAGS:
2988         /* fall through */
2989         case EXT2_IOC_SETVERSION:
2990                 error = file_has_perm(cred, file, FILE__SETATTR);
2991                 break;
2992
2993         /* sys_ioctl() checks */
2994         case FIONBIO:
2995         /* fall through */
2996         case FIOASYNC:
2997                 error = file_has_perm(cred, file, 0);
2998                 break;
2999
3000         case KDSKBENT:
3001         case KDSKBSENT:
3002                 error = task_has_capability(current, cred, CAP_SYS_TTY_CONFIG,
3003                                         SECURITY_CAP_AUDIT);
3004                 break;
3005
3006         /* default case assumes that the command will go
3007          * to the file's ioctl() function.
3008          */
3009         default:
3010                 error = file_has_perm(cred, file, FILE__IOCTL);
3011         }
3012         return error;
3013 }
3014
3015 static int default_noexec;
3016
3017 static int file_map_prot_check(struct file *file, unsigned long prot, int shared)
3018 {
3019         const struct cred *cred = current_cred();
3020         int rc = 0;
3021
3022         if (default_noexec &&
3023             (prot & PROT_EXEC) && (!file || (!shared && (prot & PROT_WRITE)))) {
3024                 /*
3025                  * We are making executable an anonymous mapping or a
3026                  * private file mapping that will also be writable.
3027                  * This has an additional check.
3028                  */
3029                 rc = cred_has_perm(cred, cred, PROCESS__EXECMEM);
3030                 if (rc)
3031                         goto error;
3032         }
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         /*
3060          * notice that we are intentionally putting the SELinux check before
3061          * the secondary cap_file_mmap check.  This is such a likely attempt
3062          * at bad behaviour/exploit that we always want to get the AVC, even
3063          * if DAC would have also denied the operation.
3064          */
3065         if (addr < CONFIG_LSM_MMAP_MIN_ADDR) {
3066                 rc = avc_has_perm(sid, sid, SECCLASS_MEMPROTECT,
3067                                   MEMPROTECT__MMAP_ZERO, NULL);
3068                 if (rc)
3069                         return rc;
3070         }
3071
3072         /* do DAC check on address space usage */
3073         rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
3074         if (rc || addr_only)
3075                 return rc;
3076
3077         if (selinux_checkreqprot)
3078                 prot = reqprot;
3079
3080         return file_map_prot_check(file, prot,
3081                                    (flags & MAP_TYPE) == MAP_SHARED);
3082 }
3083
3084 static int selinux_file_mprotect(struct vm_area_struct *vma,
3085                                  unsigned long reqprot,
3086                                  unsigned long prot)
3087 {
3088         const struct cred *cred = current_cred();
3089
3090         if (selinux_checkreqprot)
3091                 prot = reqprot;
3092
3093         if (default_noexec &&
3094             (prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
3095                 int rc = 0;
3096                 if (vma->vm_start >= vma->vm_mm->start_brk &&
3097                     vma->vm_end <= vma->vm_mm->brk) {
3098                         rc = cred_has_perm(cred, cred, PROCESS__EXECHEAP);
3099                 } else if (!vma->vm_file &&
3100                            vma->vm_start <= vma->vm_mm->start_stack &&
3101                            vma->vm_end >= vma->vm_mm->start_stack) {
3102                         rc = current_has_perm(current, PROCESS__EXECSTACK);
3103                 } else if (vma->vm_file && vma->anon_vma) {
3104                         /*
3105                          * We are making executable a file mapping that has
3106                          * had some COW done. Since pages might have been
3107                          * written, check ability to execute the possibly
3108                          * modified content.  This typically should only
3109                          * occur for text relocations.
3110                          */
3111                         rc = file_has_perm(cred, vma->vm_file, FILE__EXECMOD);
3112                 }
3113                 if (rc)
3114                         return rc;
3115         }
3116
3117         return file_map_prot_check(vma->vm_file, prot, vma->vm_flags&VM_SHARED);
3118 }
3119
3120 static int selinux_file_lock(struct file *file, unsigned int cmd)
3121 {
3122         const struct cred *cred = current_cred();
3123
3124         return file_has_perm(cred, file, FILE__LOCK);
3125 }
3126
3127 static int selinux_file_fcntl(struct file *file, unsigned int cmd,
3128                               unsigned long arg)
3129 {
3130         const struct cred *cred = current_cred();
3131         int err = 0;
3132
3133         switch (cmd) {
3134         case F_SETFL:
3135                 if (!file->f_path.dentry || !file->f_path.dentry->d_inode) {
3136                         err = -EINVAL;
3137                         break;
3138                 }
3139
3140                 if ((file->f_flags & O_APPEND) && !(arg & O_APPEND)) {
3141                         err = file_has_perm(cred, file, FILE__WRITE);
3142                         break;
3143                 }
3144                 /* fall through */
3145         case F_SETOWN:
3146         case F_SETSIG:
3147         case F_GETFL:
3148         case F_GETOWN:
3149         case F_GETSIG:
3150                 /* Just check FD__USE permission */
3151                 err = file_has_perm(cred, file, 0);
3152                 break;
3153         case F_GETLK:
3154         case F_SETLK:
3155         case F_SETLKW:
3156 #if BITS_PER_LONG == 32
3157         case F_GETLK64:
3158         case F_SETLK64:
3159         case F_SETLKW64:
3160 #endif
3161                 if (!file->f_path.dentry || !file->f_path.dentry->d_inode) {
3162                         err = -EINVAL;
3163                         break;
3164                 }
3165                 err = file_has_perm(cred, file, FILE__LOCK);
3166                 break;
3167         }
3168
3169         return err;
3170 }
3171
3172 static int selinux_file_set_fowner(struct file *file)
3173 {
3174         struct file_security_struct *fsec;
3175
3176         fsec = file->f_security;
3177         fsec->fown_sid = current_sid();
3178
3179         return 0;
3180 }
3181
3182 static int selinux_file_send_sigiotask(struct task_struct *tsk,
3183                                        struct fown_struct *fown, int signum)
3184 {
3185         struct file *file;
3186         u32 sid = task_sid(tsk);
3187         u32 perm;
3188         struct file_security_struct *fsec;
3189
3190         /* struct fown_struct is never outside the context of a struct file */
3191         file = container_of(fown, struct file, f_owner);
3192
3193         fsec = file->f_security;
3194
3195         if (!signum)
3196                 perm = signal_to_av(SIGIO); /* as per send_sigio_to_task */
3197         else
3198                 perm = signal_to_av(signum);
3199
3200         return avc_has_perm(fsec->fown_sid, sid,
3201                             SECCLASS_PROCESS, perm, NULL);
3202 }
3203
3204 static int selinux_file_receive(struct file *file)
3205 {
3206         const struct cred *cred = current_cred();
3207
3208         return file_has_perm(cred, file, file_to_av(file));
3209 }
3210
3211 static int selinux_dentry_open(struct file *file, const struct cred *cred)
3212 {
3213         struct file_security_struct *fsec;
3214         struct inode *inode;
3215         struct inode_security_struct *isec;
3216
3217         inode = file->f_path.dentry->d_inode;
3218         fsec = file->f_security;
3219         isec = inode->i_security;
3220         /*
3221          * Save inode label and policy sequence number
3222          * at open-time so that selinux_file_permission
3223          * can determine whether revalidation is necessary.
3224          * Task label is already saved in the file security
3225          * struct as its SID.
3226          */
3227         fsec->isid = isec->sid;
3228         fsec->pseqno = avc_policy_seqno();
3229         /*
3230          * Since the inode label or policy seqno may have changed
3231          * between the selinux_inode_permission check and the saving
3232          * of state above, recheck that access is still permitted.
3233          * Otherwise, access might never be revalidated against the
3234          * new inode label or new policy.
3235          * This check is not redundant - do not remove.
3236          */
3237         return inode_has_perm_noadp(cred, inode, open_file_to_av(file), 0);
3238 }
3239
3240 /* task security operations */
3241
3242 static int selinux_task_create(unsigned long clone_flags)
3243 {
3244         return current_has_perm(current, PROCESS__FORK);
3245 }
3246
3247 /*
3248  * allocate the SELinux part of blank credentials
3249  */
3250 static int selinux_cred_alloc_blank(struct cred *cred, gfp_t gfp)
3251 {
3252         struct task_security_struct *tsec;
3253
3254         tsec = kzalloc(sizeof(struct task_security_struct), gfp);
3255         if (!tsec)
3256                 return -ENOMEM;
3257
3258         cred->security = tsec;
3259         return 0;
3260 }
3261
3262 /*
3263  * detach and free the LSM part of a set of credentials
3264  */
3265 static void selinux_cred_free(struct cred *cred)
3266 {
3267         struct task_security_struct *tsec = cred->security;
3268
3269         /*
3270          * cred->security == NULL if security_cred_alloc_blank() or
3271          * security_prepare_creds() returned an error.
3272          */
3273         BUG_ON(cred->security && (unsigned long) cred->security < PAGE_SIZE);
3274         cred->security = (void *) 0x7UL;
3275         kfree(tsec);
3276 }
3277
3278 /*
3279  * prepare a new set of credentials for modification