security/apparmor/lsm.c

   1 /*
   2  * AppArmor security module
   3  *
   4  * This file contains AppArmor LSM hooks.
   5  *
   6  * Copyright (C) 1998-2008 Novell/SUSE
   7  * Copyright 2009-2010 Canonical Ltd.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation, version 2 of the
  12  * License.
  13  */
  14
  15 #include <linux/lsm_hooks.h>
  16 #include <linux/moduleparam.h>
  17 #include <linux/mm.h>
  18 #include <linux/mman.h>
  19 #include <linux/mount.h>
  20 #include <linux/namei.h>
  21 #include <linux/ptrace.h>
  22 #include <linux/ctype.h>
  23 #include <linux/sysctl.h>
  24 #include <linux/audit.h>
  25 #include <linux/user_namespace.h>
  26 #include <net/sock.h>
  27
  28 #include "include/apparmor.h"
  29 #include "include/apparmorfs.h"
  30 #include "include/audit.h"
  31 #include "include/capability.h"
  32 #include "include/context.h"
  33 #include "include/file.h"
  34 #include "include/ipc.h"
  35 #include "include/path.h"
  36 #include "include/policy.h"
  37 #include "include/procattr.h"
  38
  39 /* Flag indicating whether initialization completed */
  40 int apparmor_initialized __initdata;
  41
  42 /*
  43  * LSM hook functions
  44  */
  45
  46 /*
  47  * free the associated aa_task_cxt and put its profiles
  48  */
  49 static void apparmor_cred_free(struct cred *cred)
  50 {
  51         aa_free_task_context(cred_cxt(cred));
  52         cred_cxt(cred) = NULL;
  53 }
  54
  55 /*
  56  * allocate the apparmor part of blank credentials
  57  */
  58 static int apparmor_cred_alloc_blank(struct cred *cred, gfp_t gfp)
  59 {
  60         /* freed by apparmor_cred_free */
  61         struct aa_task_cxt *cxt = aa_alloc_task_context(gfp);
  62         if (!cxt)
  63                 return -ENOMEM;
  64
  65         cred_cxt(cred) = cxt;
  66         return 0;
  67 }
  68
  69 /*
  70  * prepare new aa_task_cxt for modification by prepare_cred block
  71  */
  72 static int apparmor_cred_prepare(struct cred *new, const struct cred *old,
  73                                  gfp_t gfp)
  74 {
  75         /* freed by apparmor_cred_free */
  76         struct aa_task_cxt *cxt = aa_alloc_task_context(gfp);
  77         if (!cxt)
  78                 return -ENOMEM;
  79
  80         aa_dup_task_context(cxt, cred_cxt(old));
  81         cred_cxt(new) = cxt;
  82         return 0;
  83 }
  84
  85 /*
  86  * transfer the apparmor data to a blank set of creds
  87  */
  88 static void apparmor_cred_transfer(struct cred *new, const struct cred *old)
  89 {
  90         const struct aa_task_cxt *old_cxt = cred_cxt(old);
  91         struct aa_task_cxt *new_cxt = cred_cxt(new);
  92
  93         aa_dup_task_context(new_cxt, old_cxt);
  94 }
  95
  96 static int apparmor_ptrace_access_check(struct task_struct *child,
  97                                         unsigned int mode)
  98 {
  99         return aa_ptrace(current, child, mode);
 100 }
 101
 102 static int apparmor_ptrace_traceme(struct task_struct *parent)
 103 {
 104         return aa_ptrace(parent, current, PTRACE_MODE_ATTACH);
 105 }
 106
 107 /* Derived from security/commoncap.c:cap_capget */
 108 static int apparmor_capget(struct task_struct *target, kernel_cap_t *effective,
 109                            kernel_cap_t *inheritable, kernel_cap_t *permitted)
 110 {
 111         struct aa_profile *profile;
 112         const struct cred *cred;
 113
 114         rcu_read_lock();
 115         cred = __task_cred(target);
 116         profile = aa_cred_profile(cred);
 117
 118         /*
 119          * cap_capget is stacked ahead of this and will
 120          * initialize effective and permitted.
 121          */
 122         if (!unconfined(profile) && !COMPLAIN_MODE(profile)) {
 123                 *effective = cap_intersect(*effective, profile->caps.allow);
 124                 *permitted = cap_intersect(*permitted, profile->caps.allow);
 125         }
 126         rcu_read_unlock();
 127
 128         return 0;
 129 }
 130
 131 static int apparmor_capable(const struct cred *cred, struct user_namespace *ns,
 132                             int cap, int audit)
 133 {
 134         struct aa_profile *profile;
 135         int error = 0;
 136
 137         profile = aa_cred_profile(cred);
 138         if (!unconfined(profile))
 139                 error = aa_capable(profile, cap, audit);
 140         return error;
 141 }
 142
 143 /**
 144  * common_perm - basic common permission check wrapper fn for paths
 145  * @op: operation being checked
 146  * @path: path to check permission of  (NOT NULL)
 147  * @mask: requested permissions mask
 148  * @cond: conditional info for the permission request  (NOT NULL)
 149  *
 150  * Returns: %0 else error code if error or permission denied
 151  */
 152 static int common_perm(int op, struct path *path, u32 mask,
 153                        struct path_cond *cond)
 154 {
 155         struct aa_profile *profile;
 156         int error = 0;
 157
 158         profile = __aa_current_profile();
 159         if (!unconfined(profile))
 160                 error = aa_path_perm(op, profile, path, 0, mask, cond);
 161
 162         return error;
 163 }
 164
 165 /**
 166  * common_perm_dir_dentry - common permission wrapper when path is dir, dentry
 167  * @op: operation being checked
 168  * @dir: directory of the dentry  (NOT NULL)
 169  * @dentry: dentry to check  (NOT NULL)
 170  * @mask: requested permissions mask
 171  * @cond: conditional info for the permission request  (NOT NULL)
 172  *
 173  * Returns: %0 else error code if error or permission denied
 174  */
 175 static int common_perm_dir_dentry(int op, struct path *dir,
 176                                   struct dentry *dentry, u32 mask,
 177                                   struct path_cond *cond)
 178 {
 179         struct path path = { dir->mnt, dentry };
 180
 181         return common_perm(op, &path, mask, cond);
 182 }
 183
 184 /**
 185  * common_perm_mnt_dentry - common permission wrapper when mnt, dentry
 186  * @op: operation being checked
 187  * @mnt: mount point of dentry (NOT NULL)
 188  * @dentry: dentry to check  (NOT NULL)
 189  * @mask: requested permissions mask
 190  *
 191  * Returns: %0 else error code if error or permission denied
 192  */
 193 static int common_perm_mnt_dentry(int op, struct vfsmount *mnt,
 194                                   struct dentry *dentry, u32 mask)
 195 {
 196         struct path path = { mnt, dentry };
 197         struct path_cond cond = { d_backing_inode(dentry)->i_uid,
 198                                   d_backing_inode(dentry)->i_mode
 199         };
 200
 201         return common_perm(op, &path, mask, &cond);
 202 }
 203
 204 /**
 205  * common_perm_rm - common permission wrapper for operations doing rm
 206  * @op: operation being checked
 207  * @dir: directory that the dentry is in  (NOT NULL)
 208  * @dentry: dentry being rm'd  (NOT NULL)
 209  * @mask: requested permission mask
 210  *
 211  * Returns: %0 else error code if error or permission denied
 212  */
 213 static int common_perm_rm(int op, struct path *dir,
 214                           struct dentry *dentry, u32 mask)
 215 {
 216         struct inode *inode = d_backing_inode(dentry);
 217         struct path_cond cond = { };
 218
 219         if (!inode || !dir->mnt || !mediated_filesystem(dentry))
 220                 return 0;
 221
 222         cond.uid = inode->i_uid;
 223         cond.mode = inode->i_mode;
 224
 225         return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
 226 }
 227
 228 /**
 229  * common_perm_create - common permission wrapper for operations doing create
 230  * @op: operation being checked
 231  * @dir: directory that dentry will be created in  (NOT NULL)
 232  * @dentry: dentry to create   (NOT NULL)
 233  * @mask: request permission mask
 234  * @mode: created file mode
 235  *
 236  * Returns: %0 else error code if error or permission denied
 237  */
 238 static int common_perm_create(int op, struct path *dir, struct dentry *dentry,
 239                               u32 mask, umode_t mode)
 240 {
 241         struct path_cond cond = { current_fsuid(), mode };
 242
 243         if (!dir->mnt || !mediated_filesystem(dir->dentry))
 244                 return 0;
 245
 246         return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
 247 }
 248
 249 static int apparmor_path_unlink(struct path *dir, struct dentry *dentry)
 250 {
 251         return common_perm_rm(OP_UNLINK, dir, dentry, AA_MAY_DELETE);
 252 }
 253
 254 static int apparmor_path_mkdir(struct path *dir, struct dentry *dentry,
 255                                umode_t mode)
 256 {
 257         return common_perm_create(OP_MKDIR, dir, dentry, AA_MAY_CREATE,
 258                                   S_IFDIR);
 259 }
 260
 261 static int apparmor_path_rmdir(struct path *dir, struct dentry *dentry)
 262 {
 263         return common_perm_rm(OP_RMDIR, dir, dentry, AA_MAY_DELETE);
 264 }
 265
 266 static int apparmor_path_mknod(struct path *dir, struct dentry *dentry,
 267                                umode_t mode, unsigned int dev)
 268 {
 269         return common_perm_create(OP_MKNOD, dir, dentry, AA_MAY_CREATE, mode);
 270 }
 271
 272 static int apparmor_path_truncate(struct path *path)
 273 {
 274         struct path_cond cond = { d_backing_inode(path->dentry)->i_uid,
 275                                   d_backing_inode(path->dentry)->i_mode
 276         };
 277
 278         if (!path->mnt || !mediated_filesystem(path->dentry))
 279                 return 0;
 280
 281         return common_perm(OP_TRUNC, path, MAY_WRITE | AA_MAY_META_WRITE,
 282                            &cond);
 283 }
 284
 285 static int apparmor_path_symlink(struct path *dir, struct dentry *dentry,
 286                                  const char *old_name)
 287 {
 288         return common_perm_create(OP_SYMLINK, dir, dentry, AA_MAY_CREATE,
 289                                   S_IFLNK);
 290 }
 291
 292 static int apparmor_path_link(struct dentry *old_dentry, struct path *new_dir,
 293                               struct dentry *new_dentry)
 294 {
 295         struct aa_profile *profile;
 296         int error = 0;
 297
 298         if (!mediated_filesystem(old_dentry))
 299                 return 0;
 300
 301         profile = aa_current_profile();
 302         if (!unconfined(profile))
 303                 error = aa_path_link(profile, old_dentry, new_dir, new_dentry);
 304         return error;
 305 }
 306
 307 static int apparmor_path_rename(struct path *old_dir, struct dentry *old_dentry,
 308                                 struct path *new_dir, struct dentry *new_dentry)
 309 {
 310         struct aa_profile *profile;
 311         int error = 0;
 312
 313         if (!mediated_filesystem(old_dentry))
 314                 return 0;
 315
 316         profile = aa_current_profile();
 317         if (!unconfined(profile)) {
 318                 struct path old_path = { old_dir->mnt, old_dentry };
 319                 struct path new_path = { new_dir->mnt, new_dentry };
 320                 struct path_cond cond = { d_backing_inode(old_dentry)->i_uid,
 321                                           d_backing_inode(old_dentry)->i_mode
 322                 };
 323
 324                 error = aa_path_perm(OP_RENAME_SRC, profile, &old_path, 0,
 325                                      MAY_READ | AA_MAY_META_READ | MAY_WRITE |
 326                                      AA_MAY_META_WRITE | AA_MAY_DELETE,
 327                                      &cond);
 328                 if (!error)
 329                         error = aa_path_perm(OP_RENAME_DEST, profile, &new_path,
 330                                              0, MAY_WRITE | AA_MAY_META_WRITE |
 331                                              AA_MAY_CREATE, &cond);
 332
 333         }
 334         return error;
 335 }
 336
 337 static int apparmor_path_chmod(struct path *path, umode_t mode)
 338 {
 339         if (!mediated_filesystem(path->dentry))
 340                 return 0;
 341
 342         return common_perm_mnt_dentry(OP_CHMOD, path->mnt, path->dentry, AA_MAY_CHMOD);
 343 }
 344
 345 static int apparmor_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 346 {
 347         struct path_cond cond =  { d_backing_inode(path->dentry)->i_uid,
 348                                    d_backing_inode(path->dentry)->i_mode
 349         };
 350
 351         if (!mediated_filesystem(path->dentry))
 352                 return 0;
 353
 354         return common_perm(OP_CHOWN, path, AA_MAY_CHOWN, &cond);
 355 }
 356
 357 static int apparmor_inode_getattr(const struct path *path)
 358 {
 359         if (!mediated_filesystem(path->dentry))
 360                 return 0;
 361
 362         return common_perm_mnt_dentry(OP_GETATTR, path->mnt, path->dentry,
 363                                       AA_MAY_META_READ);
 364 }
 365
 366 static int apparmor_file_open(struct file *file, const struct cred *cred)
 367 {
 368         struct aa_file_cxt *fcxt = file->f_security;
 369         struct aa_profile *profile;
 370         int error = 0;
 371
 372         if (!mediated_filesystem(file->f_path.dentry))
 373                 return 0;
 374
 375         /* If in exec, permission is handled by bprm hooks.
 376          * Cache permissions granted by the previous exec check, with
 377          * implicit read and executable mmap which are required to
 378          * actually execute the image.
 379          */
 380         if (current->in_execve) {
 381                 fcxt->allow = MAY_EXEC | MAY_READ | AA_EXEC_MMAP;
 382                 return 0;
 383         }
 384
 385         profile = aa_cred_profile(cred);
 386         if (!unconfined(profile)) {
 387                 struct inode *inode = file_inode(file);
 388                 struct path_cond cond = { inode->i_uid, inode->i_mode };
 389
 390                 error = aa_path_perm(OP_OPEN, profile, &file->f_path, 0,
 391                                      aa_map_file_to_perms(file), &cond);
 392                 /* todo cache full allowed permissions set and state */
 393                 fcxt->allow = aa_map_file_to_perms(file);
 394         }
 395
 396         return error;
 397 }
 398
 399 static int apparmor_file_alloc_security(struct file *file)
 400 {
 401         /* freed by apparmor_file_free_security */
 402         file->f_security = aa_alloc_file_context(GFP_KERNEL);
 403         if (!file->f_security)
 404                 return -ENOMEM;
 405         return 0;
 406
 407 }
 408
 409 static void apparmor_file_free_security(struct file *file)
 410 {
 411         struct aa_file_cxt *cxt = file->f_security;
 412
 413         aa_free_file_context(cxt);
 414 }
 415
 416 static int common_file_perm(int op, struct file *file, u32 mask)
 417 {
 418         struct aa_file_cxt *fcxt = file->f_security;
 419         struct aa_profile *profile, *fprofile = aa_cred_profile(file->f_cred);
 420         int error = 0;
 421
 422         BUG_ON(!fprofile);
 423
 424         if (!file->f_path.mnt ||
 425             !mediated_filesystem(file->f_path.dentry))
 426                 return 0;
 427
 428         profile = __aa_current_profile();
 429
 430         /* revalidate access, if task is unconfined, or the cached cred
 431          * doesn't match or if the request is for more permissions than
 432          * was granted.
 433          *
 434          * Note: the test for !unconfined(fprofile) is to handle file
 435          *       delegation from unconfined tasks
 436          */
 437         if (!unconfined(profile) && !unconfined(fprofile) &&
 438             ((fprofile != profile) || (mask & ~fcxt->allow)))
 439                 error = aa_file_perm(op, profile, file, mask);
 440
 441         return error;
 442 }
 443
 444 static int apparmor_file_permission(struct file *file, int mask)
 445 {
 446         return common_file_perm(OP_FPERM, file, mask);
 447 }
 448
 449 static int apparmor_file_lock(struct file *file, unsigned int cmd)
 450 {
 451         u32 mask = AA_MAY_LOCK;
 452
 453         if (cmd == F_WRLCK)
 454                 mask |= MAY_WRITE;
 455
 456         return common_file_perm(OP_FLOCK, file, mask);
 457 }
 458
 459 static int common_mmap(int op, struct file *file, unsigned long prot,
 460                        unsigned long flags)
 461 {
 462         int mask = 0;
 463
 464         if (!file || !file->f_security)
 465                 return 0;
 466
 467         if (prot & PROT_READ)
 468                 mask |= MAY_READ;
 469         /*
 470          * Private mappings don't require write perms since they don't
 471          * write back to the files
 472          */
 473         if ((prot & PROT_WRITE) && !(flags & MAP_PRIVATE))
 474                 mask |= MAY_WRITE;
 475         if (prot & PROT_EXEC)
 476                 mask |= AA_EXEC_MMAP;
 477
 478         return common_file_perm(op, file, mask);
 479 }
 480
 481 static int apparmor_mmap_file(struct file *file, unsigned long reqprot,
 482                               unsigned long prot, unsigned long flags)
 483 {
 484         return common_mmap(OP_FMMAP, file, prot, flags);
 485 }
 486
 487 static int apparmor_file_mprotect(struct vm_area_struct *vma,
 488                                   unsigned long reqprot, unsigned long prot)
 489 {
 490         return common_mmap(OP_FMPROT, vma->vm_file, prot,
 491                            !(vma->vm_flags & VM_SHARED) ? MAP_PRIVATE : 0);
 492 }
 493
 494 static int apparmor_getprocattr(struct task_struct *task, char *name,
 495                                 char **value)
 496 {
 497         int error = -ENOENT;
 498         /* released below */
 499         const struct cred *cred = get_task_cred(task);
 500         struct aa_task_cxt *cxt = cred_cxt(cred);
 501         struct aa_profile *profile = NULL;
 502
 503         if (strcmp(name, "current") == 0)
 504                 profile = aa_get_newest_profile(cxt->profile);
 505         else if (strcmp(name, "prev") == 0  && cxt->previous)
 506                 profile = aa_get_newest_profile(cxt->previous);
 507         else if (strcmp(name, "exec") == 0 && cxt->onexec)
 508                 profile = aa_get_newest_profile(cxt->onexec);
 509         else
 510                 error = -EINVAL;
 511
 512         if (profile)
 513                 error = aa_getprocattr(profile, value);
 514
 515         aa_put_profile(profile);
 516         put_cred(cred);
 517
 518         return error;
 519 }
 520
 521 static int apparmor_setprocattr(struct task_struct *task, char *name,
 522                                 void *value, size_t size)
 523 {
 524         struct common_audit_data sa;
 525         struct apparmor_audit_data aad = {0,};
 526         char *command, *args = value;
 527         size_t arg_size;
 528         int error;
 529
 530         if (size == 0)
 531                 return -EINVAL;
 532         /* args points to a PAGE_SIZE buffer, AppArmor requires that
 533          * the buffer must be null terminated or have size <= PAGE_SIZE -1
 534          * so that AppArmor can null terminate them
 535          */
 536         if (args[size - 1] != '\0') {
 537                 if (size == PAGE_SIZE)
 538                         return -EINVAL;
 539                 args[size] = '\0';
 540         }
 541
 542         /* task can only write its own attributes */
 543         if (current != task)
 544                 return -EACCES;
 545
 546         args = value;
 547         args = strim(args);
 548         command = strsep(&args, " ");
 549         if (!args)
 550                 return -EINVAL;
 551         args = skip_spaces(args);
 552         if (!*args)
 553                 return -EINVAL;
 554
 555         arg_size = size - (args - (char *) value);
 556         if (strcmp(name, "current") == 0) {
 557                 if (strcmp(command, "changehat") == 0) {
 558                         error = aa_setprocattr_changehat(args, arg_size,
 559                                                          !AA_DO_TEST);
 560                 } else if (strcmp(command, "permhat") == 0) {
 561                         error = aa_setprocattr_changehat(args, arg_size,
 562                                                          AA_DO_TEST);
 563                 } else if (strcmp(command, "changeprofile") == 0) {
 564                         error = aa_setprocattr_changeprofile(args, !AA_ONEXEC,
 565                                                              !AA_DO_TEST);
 566                 } else if (strcmp(command, "permprofile") == 0) {
 567                         error = aa_setprocattr_changeprofile(args, !AA_ONEXEC,
 568                                                              AA_DO_TEST);
 569                 } else
 570                         goto fail;
 571         } else if (strcmp(name, "exec") == 0) {
 572                 if (strcmp(command, "exec") == 0)
 573                         error = aa_setprocattr_changeprofile(args, AA_ONEXEC,
 574                                                              !AA_DO_TEST);
 575                 else
 576                         goto fail;
 577         } else
 578                 /* only support the "current" and "exec" process attributes */
 579                 return -EINVAL;
 580
 581         if (!error)
 582                 error = size;
 583         return error;
 584
 585 fail:
 586         sa.type = LSM_AUDIT_DATA_NONE;
 587         sa.aad = &aad;
 588         aad.profile = aa_current_profile();
 589         aad.op = OP_SETPROCATTR;
 590         aad.info = name;
 591         aad.error = -EINVAL;
 592         aa_audit_msg(AUDIT_APPARMOR_DENIED, &sa, NULL);
 593         return -EINVAL;
 594 }
 595
 596 static int apparmor_task_setrlimit(struct task_struct *task,
 597                 unsigned int resource, struct rlimit *new_rlim)
 598 {
 599         struct aa_profile *profile = __aa_current_profile();
 600         int error = 0;
 601
 602         if (!unconfined(profile))
 603                 error = aa_task_setrlimit(profile, task, resource, new_rlim);
 604
 605         return error;
 606 }
 607
 608 static struct security_hook_list apparmor_hooks[] = {
 609         LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
 610         LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
 611         LSM_HOOK_INIT(capget, apparmor_capget),
 612         LSM_HOOK_INIT(capable, apparmor_capable),
 613
 614         LSM_HOOK_INIT(path_link, apparmor_path_link),
 615         LSM_HOOK_INIT(path_unlink, apparmor_path_unlink),
 616         LSM_HOOK_INIT(path_symlink, apparmor_path_symlink),
 617         LSM_HOOK_INIT(path_mkdir, apparmor_path_mkdir),
 618         LSM_HOOK_INIT(path_rmdir, apparmor_path_rmdir),
 619         LSM_HOOK_INIT(path_mknod, apparmor_path_mknod),
 620         LSM_HOOK_INIT(path_rename, apparmor_path_rename),
 621         LSM_HOOK_INIT(path_chmod, apparmor_path_chmod),
 622         LSM_HOOK_INIT(path_chown, apparmor_path_chown),
 623         LSM_HOOK_INIT(path_truncate, apparmor_path_truncate),
 624         LSM_HOOK_INIT(inode_getattr, apparmor_inode_getattr),
 625
 626         LSM_HOOK_INIT(file_open, apparmor_file_open),
 627         LSM_HOOK_INIT(file_permission, apparmor_file_permission),
 628         LSM_HOOK_INIT(file_alloc_security, apparmor_file_alloc_security),
 629         LSM_HOOK_INIT(file_free_security, apparmor_file_free_security),
 630         LSM_HOOK_INIT(mmap_file, apparmor_mmap_file),
 631         LSM_HOOK_INIT(file_mprotect, apparmor_file_mprotect),
 632         LSM_HOOK_INIT(file_lock, apparmor_file_lock),
 633
 634         LSM_HOOK_INIT(getprocattr, apparmor_getprocattr),
 635         LSM_HOOK_INIT(setprocattr, apparmor_setprocattr),
 636
 637         LSM_HOOK_INIT(cred_alloc_blank, apparmor_cred_alloc_blank),
 638         LSM_HOOK_INIT(cred_free, apparmor_cred_free),
 639         LSM_HOOK_INIT(cred_prepare, apparmor_cred_prepare),
 640         LSM_HOOK_INIT(cred_transfer, apparmor_cred_transfer),
 641
 642         LSM_HOOK_INIT(bprm_set_creds, apparmor_bprm_set_creds),
 643         LSM_HOOK_INIT(bprm_committing_creds, apparmor_bprm_committing_creds),
 644         LSM_HOOK_INIT(bprm_committed_creds, apparmor_bprm_committed_creds),
 645         LSM_HOOK_INIT(bprm_secureexec, apparmor_bprm_secureexec),
 646
 647         LSM_HOOK_INIT(task_setrlimit, apparmor_task_setrlimit),
 648 };
 649
 650 /*
 651  * AppArmor sysfs module parameters
 652  */
 653
 654 static int param_set_aabool(const char *val, const struct kernel_param *kp);
 655 static int param_get_aabool(char *buffer, const struct kernel_param *kp);
 656 #define param_check_aabool param_check_bool
 657 static const struct kernel_param_ops param_ops_aabool = {
 658         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 659         .set = param_set_aabool,
 660         .get = param_get_aabool
 661 };
 662
 663 static int param_set_aauint(const char *val, const struct kernel_param *kp);
 664 static int param_get_aauint(char *buffer, const struct kernel_param *kp);
 665 #define param_check_aauint param_check_uint
 666 static const struct kernel_param_ops param_ops_aauint = {
 667         .set = param_set_aauint,
 668         .get = param_get_aauint
 669 };
 670
 671 static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp);
 672 static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp);
 673 #define param_check_aalockpolicy param_check_bool
 674 static const struct kernel_param_ops param_ops_aalockpolicy = {
 675         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 676         .set = param_set_aalockpolicy,
 677         .get = param_get_aalockpolicy
 678 };
 679
 680 static int param_set_audit(const char *val, struct kernel_param *kp);
 681 static int param_get_audit(char *buffer, struct kernel_param *kp);
 682
 683 static int param_set_mode(const char *val, struct kernel_param *kp);
 684 static int param_get_mode(char *buffer, struct kernel_param *kp);
 685
 686 /* Flag values, also controllable via /sys/module/apparmor/parameters
 687  * We define special types as we want to do additional mediation.
 688  */
 689
 690 /* AppArmor global enforcement switch - complain, enforce, kill */
 691 enum profile_mode aa_g_profile_mode = APPARMOR_ENFORCE;
 692 module_param_call(mode, param_set_mode, param_get_mode,
 693                   &aa_g_profile_mode, S_IRUSR | S_IWUSR);
 694
 695 /* Debug mode */
 696 bool aa_g_debug;
 697 module_param_named(debug, aa_g_debug, aabool, S_IRUSR | S_IWUSR);
 698
 699 /* Audit mode */
 700 enum audit_mode aa_g_audit;
 701 module_param_call(audit, param_set_audit, param_get_audit,
 702                   &aa_g_audit, S_IRUSR | S_IWUSR);
 703
 704 /* Determines if audit header is included in audited messages.  This
 705  * provides more context if the audit daemon is not running
 706  */
 707 bool aa_g_audit_header = 1;
 708 module_param_named(audit_header, aa_g_audit_header, aabool,
 709                    S_IRUSR | S_IWUSR);
 710
 711 /* lock out loading/removal of policy
 712  * TODO: add in at boot loading of policy, which is the only way to
 713  *       load policy, if lock_policy is set
 714  */
 715 bool aa_g_lock_policy;
 716 module_param_named(lock_policy, aa_g_lock_policy, aalockpolicy,
 717                    S_IRUSR | S_IWUSR);
 718
 719 /* Syscall logging mode */
 720 bool aa_g_logsyscall;
 721 module_param_named(logsyscall, aa_g_logsyscall, aabool, S_IRUSR | S_IWUSR);
 722
 723 /* Maximum pathname length before accesses will start getting rejected */
 724 unsigned int aa_g_path_max = 2 * PATH_MAX;
 725 module_param_named(path_max, aa_g_path_max, aauint, S_IRUSR | S_IWUSR);
 726
 727 /* Determines how paranoid loading of policy is and how much verification
 728  * on the loaded policy is done.
 729  */
 730 bool aa_g_paranoid_load = 1;
 731 module_param_named(paranoid_load, aa_g_paranoid_load, aabool,
 732                    S_IRUSR | S_IWUSR);
 733
 734 /* Boot time disable flag */
 735 static bool apparmor_enabled = CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE;
 736 module_param_named(enabled, apparmor_enabled, bool, S_IRUGO);
 737
 738 static int __init apparmor_enabled_setup(char *str)
 739 {
 740         unsigned long enabled;
 741         int error = kstrtoul(str, 0, &enabled);
 742         if (!error)
 743                 apparmor_enabled = enabled ? 1 : 0;
 744         return 1;
 745 }
 746
 747 __setup("apparmor=", apparmor_enabled_setup);
 748
 749 /* set global flag turning off the ability to load policy */
 750 static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp)
 751 {
 752         if (!capable(CAP_MAC_ADMIN))
 753                 return -EPERM;
 754         if (aa_g_lock_policy)
 755                 return -EACCES;
 756         return param_set_bool(val, kp);
 757 }
 758
 759 static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp)
 760 {
 761         if (!capable(CAP_MAC_ADMIN))
 762                 return -EPERM;
 763         return param_get_bool(buffer, kp);
 764 }
 765
 766 static int param_set_aabool(const char *val, const struct kernel_param *kp)
 767 {
 768         if (!capable(CAP_MAC_ADMIN))
 769                 return -EPERM;
 770         return param_set_bool(val, kp);
 771 }
 772
 773 static int param_get_aabool(char *buffer, const struct kernel_param *kp)
 774 {
 775         if (!capable(CAP_MAC_ADMIN))
 776                 return -EPERM;
 777         return param_get_bool(buffer, kp);
 778 }
 779
 780 static int param_set_aauint(const char *val, const struct kernel_param *kp)
 781 {
 782         if (!capable(CAP_MAC_ADMIN))
 783                 return -EPERM;
 784         return param_set_uint(val, kp);
 785 }
 786
 787 static int param_get_aauint(char *buffer, const struct kernel_param *kp)
 788 {
 789         if (!capable(CAP_MAC_ADMIN))
 790                 return -EPERM;
 791         return param_get_uint(buffer, kp);
 792 }
 793
 794 static int param_get_audit(char *buffer, struct kernel_param *kp)
 795 {
 796         if (!capable(CAP_MAC_ADMIN))
 797                 return -EPERM;
 798
 799         if (!apparmor_enabled)
 800                 return -EINVAL;
 801
 802         return sprintf(buffer, "%s", audit_mode_names[aa_g_audit]);
 803 }
 804
 805 static int param_set_audit(const char *val, struct kernel_param *kp)
 806 {
 807         int i;
 808         if (!capable(CAP_MAC_ADMIN))
 809                 return -EPERM;
 810
 811         if (!apparmor_enabled)
 812                 return -EINVAL;
 813
 814         if (!val)
 815                 return -EINVAL;
 816
 817         for (i = 0; i < AUDIT_MAX_INDEX; i++) {
 818                 if (strcmp(val, audit_mode_names[i]) == 0) {
 819                         aa_g_audit = i;
 820                         return 0;
 821                 }
 822         }
 823
 824         return -EINVAL;
 825 }
 826
 827 static int param_get_mode(char *buffer, struct kernel_param *kp)
 828 {
 829         if (!capable(CAP_MAC_ADMIN))
 830                 return -EPERM;
 831
 832         if (!apparmor_enabled)
 833                 return -EINVAL;
 834
 835         return sprintf(buffer, "%s", aa_profile_mode_names[aa_g_profile_mode]);
 836 }
 837
 838 static int param_set_mode(const char *val, struct kernel_param *kp)
 839 {
 840         int i;
 841         if (!capable(CAP_MAC_ADMIN))
 842                 return -EPERM;
 843
 844         if (!apparmor_enabled)
 845                 return -EINVAL;
 846
 847         if (!val)
 848                 return -EINVAL;
 849
 850         for (i = 0; i < APPARMOR_MODE_NAMES_MAX_INDEX; i++) {
 851                 if (strcmp(val, aa_profile_mode_names[i]) == 0) {
 852                         aa_g_profile_mode = i;
 853                         return 0;
 854                 }
 855         }
 856
 857         return -EINVAL;
 858 }
 859
 860 /*
 861  * AppArmor init functions
 862  */
 863
 864 /**
 865  * set_init_cxt - set a task context and profile on the first task.
 866  *
 867  * TODO: allow setting an alternate profile than unconfined
 868  */
 869 static int __init set_init_cxt(void)
 870 {
 871         struct cred *cred = (struct cred *)current->real_cred;
 872         struct aa_task_cxt *cxt;
 873
 874         cxt = aa_alloc_task_context(GFP_KERNEL);
 875         if (!cxt)
 876                 return -ENOMEM;
 877
 878         cxt->profile = aa_get_profile(root_ns->unconfined);
 879         cred_cxt(cred) = cxt;
 880
 881         return 0;
 882 }
 883
 884 static int __init apparmor_init(void)
 885 {
 886         int error;
 887
 888         if (!apparmor_enabled || !security_module_enable("apparmor")) {
 889                 aa_info_message("AppArmor disabled by boot time parameter");
 890                 apparmor_enabled = 0;
 891                 return 0;
 892         }
 893
 894         error = aa_alloc_root_ns();
 895         if (error) {
 896                 AA_ERROR("Unable to allocate default profile namespace\n");
 897                 goto alloc_out;
 898         }
 899
 900         error = set_init_cxt();
 901         if (error) {
 902                 AA_ERROR("Failed to set context on init task\n");
 903                 aa_free_root_ns();
 904                 goto alloc_out;
 905         }
 906         security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks));
 907
 908         /* Report that AppArmor successfully initialized */
 909         apparmor_initialized = 1;
 910         if (aa_g_profile_mode == APPARMOR_COMPLAIN)
 911                 aa_info_message("AppArmor initialized: complain mode enabled");
 912         else if (aa_g_profile_mode == APPARMOR_KILL)
 913                 aa_info_message("AppArmor initialized: kill mode enabled");
 914         else
 915                 aa_info_message("AppArmor initialized");
 916
 917         return error;
 918
 919 alloc_out:
 920         aa_destroy_aafs();
 921
 922         apparmor_enabled = 0;
 923         return error;
 924 }
 925
 926 security_initcall(apparmor_init);