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, const 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, const 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_path - common permission wrapper when mnt, dentry
 186  * @op: operation being checked
 187  * @path: location to check (NOT NULL)
 188  * @mask: requested permissions mask
 189  *
 190  * Returns: %0 else error code if error or permission denied
 191  */
 192 static inline int common_perm_path(int op, const struct path *path, u32 mask)
 193 {
 194         struct path_cond cond = { d_backing_inode(path->dentry)->i_uid,
 195                                   d_backing_inode(path->dentry)->i_mode
 196         };
 197         if (!mediated_filesystem(path->dentry))
 198                 return 0;
 199
 200         return common_perm(op, path, mask, &cond);
 201 }
 202
 203 /**
 204  * common_perm_rm - common permission wrapper for operations doing rm
 205  * @op: operation being checked
 206  * @dir: directory that the dentry is in  (NOT NULL)
 207  * @dentry: dentry being rm'd  (NOT NULL)
 208  * @mask: requested permission mask
 209  *
 210  * Returns: %0 else error code if error or permission denied
 211  */
 212 static int common_perm_rm(int op, const struct path *dir,
 213                           struct dentry *dentry, u32 mask)
 214 {
 215         struct inode *inode = d_backing_inode(dentry);
 216         struct path_cond cond = { };
 217
 218         if (!inode || !mediated_filesystem(dentry))
 219                 return 0;
 220
 221         cond.uid = inode->i_uid;
 222         cond.mode = inode->i_mode;
 223
 224         return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
 225 }
 226
 227 /**
 228  * common_perm_create - common permission wrapper for operations doing create
 229  * @op: operation being checked
 230  * @dir: directory that dentry will be created in  (NOT NULL)
 231  * @dentry: dentry to create   (NOT NULL)
 232  * @mask: request permission mask
 233  * @mode: created file mode
 234  *
 235  * Returns: %0 else error code if error or permission denied
 236  */
 237 static int common_perm_create(int op, const struct path *dir,
 238                               struct dentry *dentry, u32 mask, umode_t mode)
 239 {
 240         struct path_cond cond = { current_fsuid(), mode };
 241
 242         if (!mediated_filesystem(dir->dentry))
 243                 return 0;
 244
 245         return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
 246 }
 247
 248 static int apparmor_path_unlink(const struct path *dir, struct dentry *dentry)
 249 {
 250         return common_perm_rm(OP_UNLINK, dir, dentry, AA_MAY_DELETE);
 251 }
 252
 253 static int apparmor_path_mkdir(const struct path *dir, struct dentry *dentry,
 254                                umode_t mode)
 255 {
 256         return common_perm_create(OP_MKDIR, dir, dentry, AA_MAY_CREATE,
 257                                   S_IFDIR);
 258 }
 259
 260 static int apparmor_path_rmdir(const struct path *dir, struct dentry *dentry)
 261 {
 262         return common_perm_rm(OP_RMDIR, dir, dentry, AA_MAY_DELETE);
 263 }
 264
 265 static int apparmor_path_mknod(const struct path *dir, struct dentry *dentry,
 266                                umode_t mode, unsigned int dev)
 267 {
 268         return common_perm_create(OP_MKNOD, dir, dentry, AA_MAY_CREATE, mode);
 269 }
 270
 271 static int apparmor_path_truncate(const struct path *path)
 272 {
 273         return common_perm_path(OP_TRUNC, path, MAY_WRITE | AA_MAY_META_WRITE);
 274 }
 275
 276 static int apparmor_path_symlink(const struct path *dir, struct dentry *dentry,
 277                                  const char *old_name)
 278 {
 279         return common_perm_create(OP_SYMLINK, dir, dentry, AA_MAY_CREATE,
 280                                   S_IFLNK);
 281 }
 282
 283 static int apparmor_path_link(struct dentry *old_dentry, const struct path *new_dir,
 284                               struct dentry *new_dentry)
 285 {
 286         struct aa_profile *profile;
 287         int error = 0;
 288
 289         if (!mediated_filesystem(old_dentry))
 290                 return 0;
 291
 292         profile = aa_current_profile();
 293         if (!unconfined(profile))
 294                 error = aa_path_link(profile, old_dentry, new_dir, new_dentry);
 295         return error;
 296 }
 297
 298 static int apparmor_path_rename(const struct path *old_dir, struct dentry *old_dentry,
 299                                 const struct path *new_dir, struct dentry *new_dentry)
 300 {
 301         struct aa_profile *profile;
 302         int error = 0;
 303
 304         if (!mediated_filesystem(old_dentry))
 305                 return 0;
 306
 307         profile = aa_current_profile();
 308         if (!unconfined(profile)) {
 309                 struct path old_path = { old_dir->mnt, old_dentry };
 310                 struct path new_path = { new_dir->mnt, new_dentry };
 311                 struct path_cond cond = { d_backing_inode(old_dentry)->i_uid,
 312                                           d_backing_inode(old_dentry)->i_mode
 313                 };
 314
 315                 error = aa_path_perm(OP_RENAME_SRC, profile, &old_path, 0,
 316                                      MAY_READ | AA_MAY_META_READ | MAY_WRITE |
 317                                      AA_MAY_META_WRITE | AA_MAY_DELETE,
 318                                      &cond);
 319                 if (!error)
 320                         error = aa_path_perm(OP_RENAME_DEST, profile, &new_path,
 321                                              0, MAY_WRITE | AA_MAY_META_WRITE |
 322                                              AA_MAY_CREATE, &cond);
 323
 324         }
 325         return error;
 326 }
 327
 328 static int apparmor_path_chmod(const struct path *path, umode_t mode)
 329 {
 330         return common_perm_path(OP_CHMOD, path, AA_MAY_CHMOD);
 331 }
 332
 333 static int apparmor_path_chown(const struct path *path, kuid_t uid, kgid_t gid)
 334 {
 335         return common_perm_path(OP_CHOWN, path, AA_MAY_CHOWN);
 336 }
 337
 338 static int apparmor_inode_getattr(const struct path *path)
 339 {
 340         return common_perm_path(OP_GETATTR, path, AA_MAY_META_READ);
 341 }
 342
 343 static int apparmor_file_open(struct file *file, const struct cred *cred)
 344 {
 345         struct aa_file_cxt *fcxt = file->f_security;
 346         struct aa_profile *profile;
 347         int error = 0;
 348
 349         if (!mediated_filesystem(file->f_path.dentry))
 350                 return 0;
 351
 352         /* If in exec, permission is handled by bprm hooks.
 353          * Cache permissions granted by the previous exec check, with
 354          * implicit read and executable mmap which are required to
 355          * actually execute the image.
 356          */
 357         if (current->in_execve) {
 358                 fcxt->allow = MAY_EXEC | MAY_READ | AA_EXEC_MMAP;
 359                 return 0;
 360         }
 361
 362         profile = aa_cred_profile(cred);
 363         if (!unconfined(profile)) {
 364                 struct inode *inode = file_inode(file);
 365                 struct path_cond cond = { inode->i_uid, inode->i_mode };
 366
 367                 error = aa_path_perm(OP_OPEN, profile, &file->f_path, 0,
 368                                      aa_map_file_to_perms(file), &cond);
 369                 /* todo cache full allowed permissions set and state */
 370                 fcxt->allow = aa_map_file_to_perms(file);
 371         }
 372
 373         return error;
 374 }
 375
 376 static int apparmor_file_alloc_security(struct file *file)
 377 {
 378         /* freed by apparmor_file_free_security */
 379         file->f_security = aa_alloc_file_context(GFP_KERNEL);
 380         if (!file->f_security)
 381                 return -ENOMEM;
 382         return 0;
 383
 384 }
 385
 386 static void apparmor_file_free_security(struct file *file)
 387 {
 388         struct aa_file_cxt *cxt = file->f_security;
 389
 390         aa_free_file_context(cxt);
 391 }
 392
 393 static int common_file_perm(int op, struct file *file, u32 mask)
 394 {
 395         struct aa_file_cxt *fcxt = file->f_security;
 396         struct aa_profile *profile, *fprofile = aa_cred_profile(file->f_cred);
 397         int error = 0;
 398
 399         BUG_ON(!fprofile);
 400
 401         if (!file->f_path.mnt ||
 402             !mediated_filesystem(file->f_path.dentry))
 403                 return 0;
 404
 405         profile = __aa_current_profile();
 406
 407         /* revalidate access, if task is unconfined, or the cached cred
 408          * doesn't match or if the request is for more permissions than
 409          * was granted.
 410          *
 411          * Note: the test for !unconfined(fprofile) is to handle file
 412          *       delegation from unconfined tasks
 413          */
 414         if (!unconfined(profile) && !unconfined(fprofile) &&
 415             ((fprofile != profile) || (mask & ~fcxt->allow)))
 416                 error = aa_file_perm(op, profile, file, mask);
 417
 418         return error;
 419 }
 420
 421 static int apparmor_file_permission(struct file *file, int mask)
 422 {
 423         return common_file_perm(OP_FPERM, file, mask);
 424 }
 425
 426 static int apparmor_file_lock(struct file *file, unsigned int cmd)
 427 {
 428         u32 mask = AA_MAY_LOCK;
 429
 430         if (cmd == F_WRLCK)
 431                 mask |= MAY_WRITE;
 432
 433         return common_file_perm(OP_FLOCK, file, mask);
 434 }
 435
 436 static int common_mmap(int op, struct file *file, unsigned long prot,
 437                        unsigned long flags)
 438 {
 439         int mask = 0;
 440
 441         if (!file || !file->f_security)
 442                 return 0;
 443
 444         if (prot & PROT_READ)
 445                 mask |= MAY_READ;
 446         /*
 447          * Private mappings don't require write perms since they don't
 448          * write back to the files
 449          */
 450         if ((prot & PROT_WRITE) && !(flags & MAP_PRIVATE))
 451                 mask |= MAY_WRITE;
 452         if (prot & PROT_EXEC)
 453                 mask |= AA_EXEC_MMAP;
 454
 455         return common_file_perm(op, file, mask);
 456 }
 457
 458 static int apparmor_mmap_file(struct file *file, unsigned long reqprot,
 459                               unsigned long prot, unsigned long flags)
 460 {
 461         return common_mmap(OP_FMMAP, file, prot, flags);
 462 }
 463
 464 static int apparmor_file_mprotect(struct vm_area_struct *vma,
 465                                   unsigned long reqprot, unsigned long prot)
 466 {
 467         return common_mmap(OP_FMPROT, vma->vm_file, prot,
 468                            !(vma->vm_flags & VM_SHARED) ? MAP_PRIVATE : 0);
 469 }
 470
 471 static int apparmor_getprocattr(struct task_struct *task, char *name,
 472                                 char **value)
 473 {
 474         int error = -ENOENT;
 475         /* released below */
 476         const struct cred *cred = get_task_cred(task);
 477         struct aa_task_cxt *cxt = cred_cxt(cred);
 478         struct aa_profile *profile = NULL;
 479
 480         if (strcmp(name, "current") == 0)
 481                 profile = aa_get_newest_profile(cxt->profile);
 482         else if (strcmp(name, "prev") == 0  && cxt->previous)
 483                 profile = aa_get_newest_profile(cxt->previous);
 484         else if (strcmp(name, "exec") == 0 && cxt->onexec)
 485                 profile = aa_get_newest_profile(cxt->onexec);
 486         else
 487                 error = -EINVAL;
 488
 489         if (profile)
 490                 error = aa_getprocattr(profile, value);
 491
 492         aa_put_profile(profile);
 493         put_cred(cred);
 494
 495         return error;
 496 }
 497
 498 static int apparmor_setprocattr(struct task_struct *task, char *name,
 499                                 void *value, size_t size)
 500 {
 501         struct common_audit_data sa;
 502         struct apparmor_audit_data aad = {0,};
 503         char *command, *largs = NULL, *args = value;
 504         size_t arg_size;
 505         int error;
 506
 507         if (size == 0)
 508                 return -EINVAL;
 509         /* task can only write its own attributes */
 510         if (current != task)
 511                 return -EACCES;
 512
 513         /* AppArmor requires that the buffer must be null terminated atm */
 514         if (args[size - 1] != '\0') {
 515                 /* null terminate */
 516                 largs = args = kmalloc(size + 1, GFP_KERNEL);
 517                 if (!args)
 518                         return -ENOMEM;
 519                 memcpy(args, value, size);
 520                 args[size] = '\0';
 521         }
 522
 523         error = -EINVAL;
 524         args = strim(args);
 525         command = strsep(&args, " ");
 526         if (!args)
 527                 goto out;
 528         args = skip_spaces(args);
 529         if (!*args)
 530                 goto out;
 531
 532         arg_size = size - (args - (largs ? largs : (char *) value));
 533         if (strcmp(name, "current") == 0) {
 534                 if (strcmp(command, "changehat") == 0) {
 535                         error = aa_setprocattr_changehat(args, arg_size,
 536                                                          !AA_DO_TEST);
 537                 } else if (strcmp(command, "permhat") == 0) {
 538                         error = aa_setprocattr_changehat(args, arg_size,
 539                                                          AA_DO_TEST);
 540                 } else if (strcmp(command, "changeprofile") == 0) {
 541                         error = aa_setprocattr_changeprofile(args, !AA_ONEXEC,
 542                                                              !AA_DO_TEST);
 543                 } else if (strcmp(command, "permprofile") == 0) {
 544                         error = aa_setprocattr_changeprofile(args, !AA_ONEXEC,
 545                                                              AA_DO_TEST);
 546                 } else
 547                         goto fail;
 548         } else if (strcmp(name, "exec") == 0) {
 549                 if (strcmp(command, "exec") == 0)
 550                         error = aa_setprocattr_changeprofile(args, AA_ONEXEC,
 551                                                              !AA_DO_TEST);
 552                 else
 553                         goto fail;
 554         } else
 555                 /* only support the "current" and "exec" process attributes */
 556                 goto fail;
 557
 558         if (!error)
 559                 error = size;
 560 out:
 561         kfree(largs);
 562         return error;
 563
 564 fail:
 565         sa.type = LSM_AUDIT_DATA_NONE;
 566         sa.aad = &aad;
 567         aad.profile = aa_current_profile();
 568         aad.op = OP_SETPROCATTR;
 569         aad.info = name;
 570         aad.error = error = -EINVAL;
 571         aa_audit_msg(AUDIT_APPARMOR_DENIED, &sa, NULL);
 572         goto out;
 573 }
 574
 575 static int apparmor_task_setrlimit(struct task_struct *task,
 576                 unsigned int resource, struct rlimit *new_rlim)
 577 {
 578         struct aa_profile *profile = __aa_current_profile();
 579         int error = 0;
 580
 581         if (!unconfined(profile))
 582                 error = aa_task_setrlimit(profile, task, resource, new_rlim);
 583
 584         return error;
 585 }
 586
 587 static struct security_hook_list apparmor_hooks[] = {
 588         LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
 589         LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
 590         LSM_HOOK_INIT(capget, apparmor_capget),
 591         LSM_HOOK_INIT(capable, apparmor_capable),
 592
 593         LSM_HOOK_INIT(path_link, apparmor_path_link),
 594         LSM_HOOK_INIT(path_unlink, apparmor_path_unlink),
 595         LSM_HOOK_INIT(path_symlink, apparmor_path_symlink),
 596         LSM_HOOK_INIT(path_mkdir, apparmor_path_mkdir),
 597         LSM_HOOK_INIT(path_rmdir, apparmor_path_rmdir),
 598         LSM_HOOK_INIT(path_mknod, apparmor_path_mknod),
 599         LSM_HOOK_INIT(path_rename, apparmor_path_rename),
 600         LSM_HOOK_INIT(path_chmod, apparmor_path_chmod),
 601         LSM_HOOK_INIT(path_chown, apparmor_path_chown),
 602         LSM_HOOK_INIT(path_truncate, apparmor_path_truncate),
 603         LSM_HOOK_INIT(inode_getattr, apparmor_inode_getattr),
 604
 605         LSM_HOOK_INIT(file_open, apparmor_file_open),
 606         LSM_HOOK_INIT(file_permission, apparmor_file_permission),
 607         LSM_HOOK_INIT(file_alloc_security, apparmor_file_alloc_security),
 608         LSM_HOOK_INIT(file_free_security, apparmor_file_free_security),
 609         LSM_HOOK_INIT(mmap_file, apparmor_mmap_file),
 610         LSM_HOOK_INIT(file_mprotect, apparmor_file_mprotect),
 611         LSM_HOOK_INIT(file_lock, apparmor_file_lock),
 612
 613         LSM_HOOK_INIT(getprocattr, apparmor_getprocattr),
 614         LSM_HOOK_INIT(setprocattr, apparmor_setprocattr),
 615
 616         LSM_HOOK_INIT(cred_alloc_blank, apparmor_cred_alloc_blank),
 617         LSM_HOOK_INIT(cred_free, apparmor_cred_free),
 618         LSM_HOOK_INIT(cred_prepare, apparmor_cred_prepare),
 619         LSM_HOOK_INIT(cred_transfer, apparmor_cred_transfer),
 620
 621         LSM_HOOK_INIT(bprm_set_creds, apparmor_bprm_set_creds),
 622         LSM_HOOK_INIT(bprm_committing_creds, apparmor_bprm_committing_creds),
 623         LSM_HOOK_INIT(bprm_committed_creds, apparmor_bprm_committed_creds),
 624         LSM_HOOK_INIT(bprm_secureexec, apparmor_bprm_secureexec),
 625
 626         LSM_HOOK_INIT(task_setrlimit, apparmor_task_setrlimit),
 627 };
 628
 629 /*
 630  * AppArmor sysfs module parameters
 631  */
 632
 633 static int param_set_aabool(const char *val, const struct kernel_param *kp);
 634 static int param_get_aabool(char *buffer, const struct kernel_param *kp);
 635 #define param_check_aabool param_check_bool
 636 static const struct kernel_param_ops param_ops_aabool = {
 637         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 638         .set = param_set_aabool,
 639         .get = param_get_aabool
 640 };
 641
 642 static int param_set_aauint(const char *val, const struct kernel_param *kp);
 643 static int param_get_aauint(char *buffer, const struct kernel_param *kp);
 644 #define param_check_aauint param_check_uint
 645 static const struct kernel_param_ops param_ops_aauint = {
 646         .set = param_set_aauint,
 647         .get = param_get_aauint
 648 };
 649
 650 static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp);
 651 static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp);
 652 #define param_check_aalockpolicy param_check_bool
 653 static const struct kernel_param_ops param_ops_aalockpolicy = {
 654         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 655         .set = param_set_aalockpolicy,
 656         .get = param_get_aalockpolicy
 657 };
 658
 659 static int param_set_audit(const char *val, struct kernel_param *kp);
 660 static int param_get_audit(char *buffer, struct kernel_param *kp);
 661
 662 static int param_set_mode(const char *val, struct kernel_param *kp);
 663 static int param_get_mode(char *buffer, struct kernel_param *kp);
 664
 665 /* Flag values, also controllable via /sys/module/apparmor/parameters
 666  * We define special types as we want to do additional mediation.
 667  */
 668
 669 /* AppArmor global enforcement switch - complain, enforce, kill */
 670 enum profile_mode aa_g_profile_mode = APPARMOR_ENFORCE;
 671 module_param_call(mode, param_set_mode, param_get_mode,
 672                   &aa_g_profile_mode, S_IRUSR | S_IWUSR);
 673
 674 #ifdef CONFIG_SECURITY_APPARMOR_HASH
 675 /* whether policy verification hashing is enabled */
 676 bool aa_g_hash_policy = IS_ENABLED(CONFIG_SECURITY_APPARMOR_HASH_DEFAULT);
 677 module_param_named(hash_policy, aa_g_hash_policy, aabool, S_IRUSR | S_IWUSR);
 678 #endif
 679
 680 /* Debug mode */
 681 bool aa_g_debug;
 682 module_param_named(debug, aa_g_debug, aabool, S_IRUSR | S_IWUSR);
 683
 684 /* Audit mode */
 685 enum audit_mode aa_g_audit;
 686 module_param_call(audit, param_set_audit, param_get_audit,
 687                   &aa_g_audit, S_IRUSR | S_IWUSR);
 688
 689 /* Determines if audit header is included in audited messages.  This
 690  * provides more context if the audit daemon is not running
 691  */
 692 bool aa_g_audit_header = 1;
 693 module_param_named(audit_header, aa_g_audit_header, aabool,
 694                    S_IRUSR | S_IWUSR);
 695
 696 /* lock out loading/removal of policy
 697  * TODO: add in at boot loading of policy, which is the only way to
 698  *       load policy, if lock_policy is set
 699  */
 700 bool aa_g_lock_policy;
 701 module_param_named(lock_policy, aa_g_lock_policy, aalockpolicy,
 702                    S_IRUSR | S_IWUSR);
 703
 704 /* Syscall logging mode */
 705 bool aa_g_logsyscall;
 706 module_param_named(logsyscall, aa_g_logsyscall, aabool, S_IRUSR | S_IWUSR);
 707
 708 /* Maximum pathname length before accesses will start getting rejected */
 709 unsigned int aa_g_path_max = 2 * PATH_MAX;
 710 module_param_named(path_max, aa_g_path_max, aauint, S_IRUSR | S_IWUSR);
 711
 712 /* Determines how paranoid loading of policy is and how much verification
 713  * on the loaded policy is done.
 714  */
 715 bool aa_g_paranoid_load = 1;
 716 module_param_named(paranoid_load, aa_g_paranoid_load, aabool,
 717                    S_IRUSR | S_IWUSR);
 718
 719 /* Boot time disable flag */
 720 static bool apparmor_enabled = CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE;
 721 module_param_named(enabled, apparmor_enabled, bool, S_IRUGO);
 722
 723 static int __init apparmor_enabled_setup(char *str)
 724 {
 725         unsigned long enabled;
 726         int error = kstrtoul(str, 0, &enabled);
 727         if (!error)
 728                 apparmor_enabled = enabled ? 1 : 0;
 729         return 1;
 730 }
 731
 732 __setup("apparmor=", apparmor_enabled_setup);
 733
 734 /* set global flag turning off the ability to load policy */
 735 static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp)
 736 {
 737         if (!policy_admin_capable())
 738                 return -EPERM;
 739         return param_set_bool(val, kp);
 740 }
 741
 742 static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp)
 743 {
 744         if (!policy_view_capable())
 745                 return -EPERM;
 746         return param_get_bool(buffer, kp);
 747 }
 748
 749 static int param_set_aabool(const char *val, const struct kernel_param *kp)
 750 {
 751         if (!policy_admin_capable())
 752                 return -EPERM;
 753         return param_set_bool(val, kp);
 754 }
 755
 756 static int param_get_aabool(char *buffer, const struct kernel_param *kp)
 757 {
 758         if (!policy_view_capable())
 759                 return -EPERM;
 760         return param_get_bool(buffer, kp);
 761 }
 762
 763 static int param_set_aauint(const char *val, const struct kernel_param *kp)
 764 {
 765         if (!policy_admin_capable())
 766                 return -EPERM;
 767         return param_set_uint(val, kp);
 768 }
 769
 770 static int param_get_aauint(char *buffer, const struct kernel_param *kp)
 771 {
 772         if (!policy_view_capable())
 773                 return -EPERM;
 774         return param_get_uint(buffer, kp);
 775 }
 776
 777 static int param_get_audit(char *buffer, struct kernel_param *kp)
 778 {
 779         if (!policy_view_capable())
 780                 return -EPERM;
 781
 782         if (!apparmor_enabled)
 783                 return -EINVAL;
 784
 785         return sprintf(buffer, "%s", audit_mode_names[aa_g_audit]);
 786 }
 787
 788 static int param_set_audit(const char *val, struct kernel_param *kp)
 789 {
 790         int i;
 791         if (!policy_admin_capable())
 792                 return -EPERM;
 793
 794         if (!apparmor_enabled)
 795                 return -EINVAL;
 796
 797         if (!val)
 798                 return -EINVAL;
 799
 800         for (i = 0; i < AUDIT_MAX_INDEX; i++) {
 801                 if (strcmp(val, audit_mode_names[i]) == 0) {
 802                         aa_g_audit = i;
 803                         return 0;
 804                 }
 805         }
 806
 807         return -EINVAL;
 808 }
 809
 810 static int param_get_mode(char *buffer, struct kernel_param *kp)
 811 {
 812         if (!policy_admin_capable())
 813                 return -EPERM;
 814
 815         if (!apparmor_enabled)
 816                 return -EINVAL;
 817
 818         return sprintf(buffer, "%s", aa_profile_mode_names[aa_g_profile_mode]);
 819 }
 820
 821 static int param_set_mode(const char *val, struct kernel_param *kp)
 822 {
 823         int i;
 824         if (!policy_admin_capable())
 825                 return -EPERM;
 826
 827         if (!apparmor_enabled)
 828                 return -EINVAL;
 829
 830         if (!val)
 831                 return -EINVAL;
 832
 833         for (i = 0; i < APPARMOR_MODE_NAMES_MAX_INDEX; i++) {
 834                 if (strcmp(val, aa_profile_mode_names[i]) == 0) {
 835                         aa_g_profile_mode = i;
 836                         return 0;
 837                 }
 838         }
 839
 840         return -EINVAL;
 841 }
 842
 843 /*
 844  * AppArmor init functions
 845  */
 846
 847 /**
 848  * set_init_cxt - set a task context and profile on the first task.
 849  *
 850  * TODO: allow setting an alternate profile than unconfined
 851  */
 852 static int __init set_init_cxt(void)
 853 {
 854         struct cred *cred = (struct cred *)current->real_cred;
 855         struct aa_task_cxt *cxt;
 856
 857         cxt = aa_alloc_task_context(GFP_KERNEL);
 858         if (!cxt)
 859                 return -ENOMEM;
 860
 861         cxt->profile = aa_get_profile(root_ns->unconfined);
 862         cred_cxt(cred) = cxt;
 863
 864         return 0;
 865 }
 866
 867 static int __init apparmor_init(void)
 868 {
 869         int error;
 870
 871         if (!apparmor_enabled || !security_module_enable("apparmor")) {
 872                 aa_info_message("AppArmor disabled by boot time parameter");
 873                 apparmor_enabled = 0;
 874                 return 0;
 875         }
 876
 877         error = aa_alloc_root_ns();
 878         if (error) {
 879                 AA_ERROR("Unable to allocate default profile namespace\n");
 880                 goto alloc_out;
 881         }
 882
 883         error = set_init_cxt();
 884         if (error) {
 885                 AA_ERROR("Failed to set context on init task\n");
 886                 aa_free_root_ns();
 887                 goto alloc_out;
 888         }
 889         security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks));
 890
 891         /* Report that AppArmor successfully initialized */
 892         apparmor_initialized = 1;
 893         if (aa_g_profile_mode == APPARMOR_COMPLAIN)
 894                 aa_info_message("AppArmor initialized: complain mode enabled");
 895         else if (aa_g_profile_mode == APPARMOR_KILL)
 896                 aa_info_message("AppArmor initialized: kill mode enabled");
 897         else
 898                 aa_info_message("AppArmor initialized");
 899
 900         return error;
 901
 902 alloc_out:
 903         aa_destroy_aafs();
 904
 905         apparmor_enabled = 0;
 906         return error;
 907 }
 908
 909 security_initcall(apparmor_init);