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 <linux/kmemleak.h>
  27 #include <net/sock.h>
  28
  29 #include "include/apparmor.h"
  30 #include "include/apparmorfs.h"
  31 #include "include/audit.h"
  32 #include "include/capability.h"
  33 #include "include/context.h"
  34 #include "include/file.h"
  35 #include "include/ipc.h"
  36 #include "include/path.h"
  37 #include "include/label.h"
  38 #include "include/policy.h"
  39 #include "include/policy_ns.h"
  40 #include "include/procattr.h"
  41 #include "include/mount.h"
  42
  43 /* Flag indicating whether initialization completed */
  44 int apparmor_initialized;
  45
  46 DEFINE_PER_CPU(struct aa_buffers, aa_buffers);
  47
  48
  49 /*
  50  * LSM hook functions
  51  */
  52
  53 /*
  54  * free the associated aa_task_ctx and put its labels
  55  */
  56 static void apparmor_cred_free(struct cred *cred)
  57 {
  58         aa_free_task_context(cred_ctx(cred));
  59         cred_ctx(cred) = NULL;
  60 }
  61
  62 /*
  63  * allocate the apparmor part of blank credentials
  64  */
  65 static int apparmor_cred_alloc_blank(struct cred *cred, gfp_t gfp)
  66 {
  67         /* freed by apparmor_cred_free */
  68         struct aa_task_ctx *ctx = aa_alloc_task_context(gfp);
  69
  70         if (!ctx)
  71                 return -ENOMEM;
  72
  73         cred_ctx(cred) = ctx;
  74         return 0;
  75 }
  76
  77 /*
  78  * prepare new aa_task_ctx for modification by prepare_cred block
  79  */
  80 static int apparmor_cred_prepare(struct cred *new, const struct cred *old,
  81                                  gfp_t gfp)
  82 {
  83         /* freed by apparmor_cred_free */
  84         struct aa_task_ctx *ctx = aa_alloc_task_context(gfp);
  85
  86         if (!ctx)
  87                 return -ENOMEM;
  88
  89         aa_dup_task_context(ctx, cred_ctx(old));
  90         cred_ctx(new) = ctx;
  91         return 0;
  92 }
  93
  94 /*
  95  * transfer the apparmor data to a blank set of creds
  96  */
  97 static void apparmor_cred_transfer(struct cred *new, const struct cred *old)
  98 {
  99         const struct aa_task_ctx *old_ctx = cred_ctx(old);
 100         struct aa_task_ctx *new_ctx = cred_ctx(new);
 101
 102         aa_dup_task_context(new_ctx, old_ctx);
 103 }
 104
 105 static int apparmor_ptrace_access_check(struct task_struct *child,
 106                                         unsigned int mode)
 107 {
 108         struct aa_label *tracer, *tracee;
 109         int error;
 110
 111         tracer = begin_current_label_crit_section();
 112         tracee = aa_get_task_label(child);
 113         error = aa_may_ptrace(tracer, tracee,
 114                   mode == PTRACE_MODE_READ ? AA_PTRACE_READ : AA_PTRACE_TRACE);
 115         aa_put_label(tracee);
 116         end_current_label_crit_section(tracer);
 117
 118         return error;
 119 }
 120
 121 static int apparmor_ptrace_traceme(struct task_struct *parent)
 122 {
 123         struct aa_label *tracer, *tracee;
 124         int error;
 125
 126         tracee = begin_current_label_crit_section();
 127         tracer = aa_get_task_label(parent);
 128         error = aa_may_ptrace(tracer, tracee, AA_PTRACE_TRACE);
 129         aa_put_label(tracer);
 130         end_current_label_crit_section(tracee);
 131
 132         return error;
 133 }
 134
 135 /* Derived from security/commoncap.c:cap_capget */
 136 static int apparmor_capget(struct task_struct *target, kernel_cap_t *effective,
 137                            kernel_cap_t *inheritable, kernel_cap_t *permitted)
 138 {
 139         struct aa_label *label;
 140         const struct cred *cred;
 141
 142         rcu_read_lock();
 143         cred = __task_cred(target);
 144         label = aa_get_newest_cred_label(cred);
 145
 146         /*
 147          * cap_capget is stacked ahead of this and will
 148          * initialize effective and permitted.
 149          */
 150         if (!unconfined(label)) {
 151                 struct aa_profile *profile;
 152                 struct label_it i;
 153
 154                 label_for_each_confined(i, label, profile) {
 155                         if (COMPLAIN_MODE(profile))
 156                                 continue;
 157                         *effective = cap_intersect(*effective,
 158                                                    profile->caps.allow);
 159                         *permitted = cap_intersect(*permitted,
 160                                                    profile->caps.allow);
 161                 }
 162         }
 163         rcu_read_unlock();
 164         aa_put_label(label);
 165
 166         return 0;
 167 }
 168
 169 static int apparmor_capable(const struct cred *cred, struct user_namespace *ns,
 170                             int cap, int audit)
 171 {
 172         struct aa_label *label;
 173         int error = 0;
 174
 175         label = aa_get_newest_cred_label(cred);
 176         if (!unconfined(label))
 177                 error = aa_capable(label, cap, audit);
 178         aa_put_label(label);
 179
 180         return error;
 181 }
 182
 183 /**
 184  * common_perm - basic common permission check wrapper fn for paths
 185  * @op: operation being checked
 186  * @path: path to check permission of  (NOT NULL)
 187  * @mask: requested permissions mask
 188  * @cond: conditional info for the permission request  (NOT NULL)
 189  *
 190  * Returns: %0 else error code if error or permission denied
 191  */
 192 static int common_perm(const char *op, const struct path *path, u32 mask,
 193                        struct path_cond *cond)
 194 {
 195         struct aa_label *label;
 196         int error = 0;
 197
 198         label = __begin_current_label_crit_section();
 199         if (!unconfined(label))
 200                 error = aa_path_perm(op, label, path, 0, mask, cond);
 201         __end_current_label_crit_section(label);
 202
 203         return error;
 204 }
 205
 206 /**
 207  * common_perm_cond - common permission wrapper around inode cond
 208  * @op: operation being checked
 209  * @path: location to check (NOT NULL)
 210  * @mask: requested permissions mask
 211  *
 212  * Returns: %0 else error code if error or permission denied
 213  */
 214 static int common_perm_cond(const char *op, const struct path *path, u32 mask)
 215 {
 216         struct path_cond cond = { d_backing_inode(path->dentry)->i_uid,
 217                                   d_backing_inode(path->dentry)->i_mode
 218         };
 219
 220         if (!path_mediated_fs(path->dentry))
 221                 return 0;
 222
 223         return common_perm(op, path, mask, &cond);
 224 }
 225
 226 /**
 227  * common_perm_dir_dentry - common permission wrapper when path is dir, dentry
 228  * @op: operation being checked
 229  * @dir: directory of the dentry  (NOT NULL)
 230  * @dentry: dentry to check  (NOT NULL)
 231  * @mask: requested permissions mask
 232  * @cond: conditional info for the permission request  (NOT NULL)
 233  *
 234  * Returns: %0 else error code if error or permission denied
 235  */
 236 static int common_perm_dir_dentry(const char *op, const struct path *dir,
 237                                   struct dentry *dentry, u32 mask,
 238                                   struct path_cond *cond)
 239 {
 240         struct path path = { .mnt = dir->mnt, .dentry = dentry };
 241
 242         return common_perm(op, &path, mask, cond);
 243 }
 244
 245 /**
 246  * common_perm_rm - common permission wrapper for operations doing rm
 247  * @op: operation being checked
 248  * @dir: directory that the dentry is in  (NOT NULL)
 249  * @dentry: dentry being rm'd  (NOT NULL)
 250  * @mask: requested permission mask
 251  *
 252  * Returns: %0 else error code if error or permission denied
 253  */
 254 static int common_perm_rm(const char *op, const struct path *dir,
 255                           struct dentry *dentry, u32 mask)
 256 {
 257         struct inode *inode = d_backing_inode(dentry);
 258         struct path_cond cond = { };
 259
 260         if (!inode || !path_mediated_fs(dentry))
 261                 return 0;
 262
 263         cond.uid = inode->i_uid;
 264         cond.mode = inode->i_mode;
 265
 266         return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
 267 }
 268
 269 /**
 270  * common_perm_create - common permission wrapper for operations doing create
 271  * @op: operation being checked
 272  * @dir: directory that dentry will be created in  (NOT NULL)
 273  * @dentry: dentry to create   (NOT NULL)
 274  * @mask: request permission mask
 275  * @mode: created file mode
 276  *
 277  * Returns: %0 else error code if error or permission denied
 278  */
 279 static int common_perm_create(const char *op, const struct path *dir,
 280                               struct dentry *dentry, u32 mask, umode_t mode)
 281 {
 282         struct path_cond cond = { current_fsuid(), mode };
 283
 284         if (!path_mediated_fs(dir->dentry))
 285                 return 0;
 286
 287         return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
 288 }
 289
 290 static int apparmor_path_unlink(const struct path *dir, struct dentry *dentry)
 291 {
 292         return common_perm_rm(OP_UNLINK, dir, dentry, AA_MAY_DELETE);
 293 }
 294
 295 static int apparmor_path_mkdir(const struct path *dir, struct dentry *dentry,
 296                                umode_t mode)
 297 {
 298         return common_perm_create(OP_MKDIR, dir, dentry, AA_MAY_CREATE,
 299                                   S_IFDIR);
 300 }
 301
 302 static int apparmor_path_rmdir(const struct path *dir, struct dentry *dentry)
 303 {
 304         return common_perm_rm(OP_RMDIR, dir, dentry, AA_MAY_DELETE);
 305 }
 306
 307 static int apparmor_path_mknod(const struct path *dir, struct dentry *dentry,
 308                                umode_t mode, unsigned int dev)
 309 {
 310         return common_perm_create(OP_MKNOD, dir, dentry, AA_MAY_CREATE, mode);
 311 }
 312
 313 static int apparmor_path_truncate(const struct path *path)
 314 {
 315         return common_perm_cond(OP_TRUNC, path, MAY_WRITE | AA_MAY_SETATTR);
 316 }
 317
 318 static int apparmor_path_symlink(const struct path *dir, struct dentry *dentry,
 319                                  const char *old_name)
 320 {
 321         return common_perm_create(OP_SYMLINK, dir, dentry, AA_MAY_CREATE,
 322                                   S_IFLNK);
 323 }
 324
 325 static int apparmor_path_link(struct dentry *old_dentry, const struct path *new_dir,
 326                               struct dentry *new_dentry)
 327 {
 328         struct aa_label *label;
 329         int error = 0;
 330
 331         if (!path_mediated_fs(old_dentry))
 332                 return 0;
 333
 334         label = begin_current_label_crit_section();
 335         if (!unconfined(label))
 336                 error = aa_path_link(label, old_dentry, new_dir, new_dentry);
 337         end_current_label_crit_section(label);
 338
 339         return error;
 340 }
 341
 342 static int apparmor_path_rename(const struct path *old_dir, struct dentry *old_dentry,
 343                                 const struct path *new_dir, struct dentry *new_dentry)
 344 {
 345         struct aa_label *label;
 346         int error = 0;
 347
 348         if (!path_mediated_fs(old_dentry))
 349                 return 0;
 350
 351         label = begin_current_label_crit_section();
 352         if (!unconfined(label)) {
 353                 struct path old_path = { .mnt = old_dir->mnt,
 354                                          .dentry = old_dentry };
 355                 struct path new_path = { .mnt = new_dir->mnt,
 356                                          .dentry = new_dentry };
 357                 struct path_cond cond = { d_backing_inode(old_dentry)->i_uid,
 358                                           d_backing_inode(old_dentry)->i_mode
 359                 };
 360
 361                 error = aa_path_perm(OP_RENAME_SRC, label, &old_path, 0,
 362                                      MAY_READ | AA_MAY_GETATTR | MAY_WRITE |
 363                                      AA_MAY_SETATTR | AA_MAY_DELETE,
 364                                      &cond);
 365                 if (!error)
 366                         error = aa_path_perm(OP_RENAME_DEST, label, &new_path,
 367                                              0, MAY_WRITE | AA_MAY_SETATTR |
 368                                              AA_MAY_CREATE, &cond);
 369
 370         }
 371         end_current_label_crit_section(label);
 372
 373         return error;
 374 }
 375
 376 static int apparmor_path_chmod(const struct path *path, umode_t mode)
 377 {
 378         return common_perm_cond(OP_CHMOD, path, AA_MAY_CHMOD);
 379 }
 380
 381 static int apparmor_path_chown(const struct path *path, kuid_t uid, kgid_t gid)
 382 {
 383         return common_perm_cond(OP_CHOWN, path, AA_MAY_CHOWN);
 384 }
 385
 386 static int apparmor_inode_getattr(const struct path *path)
 387 {
 388         return common_perm_cond(OP_GETATTR, path, AA_MAY_GETATTR);
 389 }
 390
 391 static int apparmor_file_open(struct file *file, const struct cred *cred)
 392 {
 393         struct aa_file_ctx *fctx = file_ctx(file);
 394         struct aa_label *label;
 395         int error = 0;
 396
 397         if (!path_mediated_fs(file->f_path.dentry))
 398                 return 0;
 399
 400         /* If in exec, permission is handled by bprm hooks.
 401          * Cache permissions granted by the previous exec check, with
 402          * implicit read and executable mmap which are required to
 403          * actually execute the image.
 404          */
 405         if (current->in_execve) {
 406                 fctx->allow = MAY_EXEC | MAY_READ | AA_EXEC_MMAP;
 407                 return 0;
 408         }
 409
 410         label = aa_get_newest_cred_label(cred);
 411         if (!unconfined(label)) {
 412                 struct inode *inode = file_inode(file);
 413                 struct path_cond cond = { inode->i_uid, inode->i_mode };
 414
 415                 error = aa_path_perm(OP_OPEN, label, &file->f_path, 0,
 416                                      aa_map_file_to_perms(file), &cond);
 417                 /* todo cache full allowed permissions set and state */
 418                 fctx->allow = aa_map_file_to_perms(file);
 419         }
 420         aa_put_label(label);
 421
 422         return error;
 423 }
 424
 425 static int apparmor_file_alloc_security(struct file *file)
 426 {
 427         int error = 0;
 428
 429         /* freed by apparmor_file_free_security */
 430         struct aa_label *label = begin_current_label_crit_section();
 431         file->f_security = aa_alloc_file_ctx(label, GFP_KERNEL);
 432         if (!file_ctx(file))
 433                 error = -ENOMEM;
 434         end_current_label_crit_section(label);
 435
 436         return error;
 437 }
 438
 439 static void apparmor_file_free_security(struct file *file)
 440 {
 441         aa_free_file_ctx(file_ctx(file));
 442 }
 443
 444 static int common_file_perm(const char *op, struct file *file, u32 mask)
 445 {
 446         struct aa_label *label;
 447         int error = 0;
 448
 449         /* don't reaudit files closed during inheritance */
 450         if (file->f_path.dentry == aa_null.dentry)
 451                 return -EACCES;
 452
 453         label = __begin_current_label_crit_section();
 454         error = aa_file_perm(op, label, file, mask);
 455         __end_current_label_crit_section(label);
 456
 457         return error;
 458 }
 459
 460 static int apparmor_file_receive(struct file *file)
 461 {
 462         return common_file_perm(OP_FRECEIVE, file, aa_map_file_to_perms(file));
 463 }
 464
 465 static int apparmor_file_permission(struct file *file, int mask)
 466 {
 467         return common_file_perm(OP_FPERM, file, mask);
 468 }
 469
 470 static int apparmor_file_lock(struct file *file, unsigned int cmd)
 471 {
 472         u32 mask = AA_MAY_LOCK;
 473
 474         if (cmd == F_WRLCK)
 475                 mask |= MAY_WRITE;
 476
 477         return common_file_perm(OP_FLOCK, file, mask);
 478 }
 479
 480 static int common_mmap(const char *op, struct file *file, unsigned long prot,
 481                        unsigned long flags)
 482 {
 483         int mask = 0;
 484
 485         if (!file || !file_ctx(file))
 486                 return 0;
 487
 488         if (prot & PROT_READ)
 489                 mask |= MAY_READ;
 490         /*
 491          * Private mappings don't require write perms since they don't
 492          * write back to the files
 493          */
 494         if ((prot & PROT_WRITE) && !(flags & MAP_PRIVATE))
 495                 mask |= MAY_WRITE;
 496         if (prot & PROT_EXEC)
 497                 mask |= AA_EXEC_MMAP;
 498
 499         return common_file_perm(op, file, mask);
 500 }
 501
 502 static int apparmor_mmap_file(struct file *file, unsigned long reqprot,
 503                               unsigned long prot, unsigned long flags)
 504 {
 505         return common_mmap(OP_FMMAP, file, prot, flags);
 506 }
 507
 508 static int apparmor_file_mprotect(struct vm_area_struct *vma,
 509                                   unsigned long reqprot, unsigned long prot)
 510 {
 511         return common_mmap(OP_FMPROT, vma->vm_file, prot,
 512                            !(vma->vm_flags & VM_SHARED) ? MAP_PRIVATE : 0);
 513 }
 514
 515 static int apparmor_sb_mount(const char *dev_name, const struct path *path,
 516                              const char *type, unsigned long flags, void *data)
 517 {
 518         struct aa_label *label;
 519         int error = 0;
 520
 521         /* Discard magic */
 522         if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
 523                 flags &= ~MS_MGC_MSK;
 524
 525         flags &= ~AA_MS_IGNORE_MASK;
 526
 527         label = __begin_current_label_crit_section();
 528         if (!unconfined(label)) {
 529                 if (flags & MS_REMOUNT)
 530                         error = aa_remount(label, path, flags, data);
 531                 else if (flags & MS_BIND)
 532                         error = aa_bind_mount(label, path, dev_name, flags);
 533                 else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE |
 534                                   MS_UNBINDABLE))
 535                         error = aa_mount_change_type(label, path, flags);
 536                 else if (flags & MS_MOVE)
 537                         error = aa_move_mount(label, path, dev_name);
 538                 else
 539                         error = aa_new_mount(label, dev_name, path, type,
 540                                              flags, data);
 541         }
 542         __end_current_label_crit_section(label);
 543
 544         return error;
 545 }
 546
 547 static int apparmor_sb_umount(struct vfsmount *mnt, int flags)
 548 {
 549         struct aa_label *label;
 550         int error = 0;
 551
 552         label = __begin_current_label_crit_section();
 553         if (!unconfined(label))
 554                 error = aa_umount(label, mnt, flags);
 555         __end_current_label_crit_section(label);
 556
 557         return error;
 558 }
 559
 560 static int apparmor_sb_pivotroot(const struct path *old_path,
 561                                  const struct path *new_path)
 562 {
 563         struct aa_label *label;
 564         int error = 0;
 565
 566         label = aa_get_current_label();
 567         if (!unconfined(label))
 568                 error = aa_pivotroot(label, old_path, new_path);
 569         aa_put_label(label);
 570
 571         return error;
 572 }
 573
 574 static int apparmor_getprocattr(struct task_struct *task, char *name,
 575                                 char **value)
 576 {
 577         int error = -ENOENT;
 578         /* released below */
 579         const struct cred *cred = get_task_cred(task);
 580         struct aa_task_ctx *ctx = cred_ctx(cred);
 581         struct aa_label *label = NULL;
 582
 583         if (strcmp(name, "current") == 0)
 584                 label = aa_get_newest_label(ctx->label);
 585         else if (strcmp(name, "prev") == 0  && ctx->previous)
 586                 label = aa_get_newest_label(ctx->previous);
 587         else if (strcmp(name, "exec") == 0 && ctx->onexec)
 588                 label = aa_get_newest_label(ctx->onexec);
 589         else
 590                 error = -EINVAL;
 591
 592         if (label)
 593                 error = aa_getprocattr(label, value);
 594
 595         aa_put_label(label);
 596         put_cred(cred);
 597
 598         return error;
 599 }
 600
 601 static int apparmor_setprocattr(const char *name, void *value,
 602                                 size_t size)
 603 {
 604         char *command, *largs = NULL, *args = value;
 605         size_t arg_size;
 606         int error;
 607         DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SETPROCATTR);
 608
 609         if (size == 0)
 610                 return -EINVAL;
 611
 612         /* AppArmor requires that the buffer must be null terminated atm */
 613         if (args[size - 1] != '\0') {
 614                 /* null terminate */
 615                 largs = args = kmalloc(size + 1, GFP_KERNEL);
 616                 if (!args)
 617                         return -ENOMEM;
 618                 memcpy(args, value, size);
 619                 args[size] = '\0';
 620         }
 621
 622         error = -EINVAL;
 623         args = strim(args);
 624         command = strsep(&args, " ");
 625         if (!args)
 626                 goto out;
 627         args = skip_spaces(args);
 628         if (!*args)
 629                 goto out;
 630
 631         arg_size = size - (args - (largs ? largs : (char *) value));
 632         if (strcmp(name, "current") == 0) {
 633                 if (strcmp(command, "changehat") == 0) {
 634                         error = aa_setprocattr_changehat(args, arg_size,
 635                                                          AA_CHANGE_NOFLAGS);
 636                 } else if (strcmp(command, "permhat") == 0) {
 637                         error = aa_setprocattr_changehat(args, arg_size,
 638                                                          AA_CHANGE_TEST);
 639                 } else if (strcmp(command, "changeprofile") == 0) {
 640                         error = aa_change_profile(args, AA_CHANGE_NOFLAGS);
 641                 } else if (strcmp(command, "permprofile") == 0) {
 642                         error = aa_change_profile(args, AA_CHANGE_TEST);
 643                 } else if (strcmp(command, "stack") == 0) {
 644                         error = aa_change_profile(args, AA_CHANGE_STACK);
 645                 } else
 646                         goto fail;
 647         } else if (strcmp(name, "exec") == 0) {
 648                 if (strcmp(command, "exec") == 0)
 649                         error = aa_change_profile(args, AA_CHANGE_ONEXEC);
 650                 else if (strcmp(command, "stack") == 0)
 651                         error = aa_change_profile(args, (AA_CHANGE_ONEXEC |
 652                                                          AA_CHANGE_STACK));
 653                 else
 654                         goto fail;
 655         } else
 656                 /* only support the "current" and "exec" process attributes */
 657                 goto fail;
 658
 659         if (!error)
 660                 error = size;
 661 out:
 662         kfree(largs);
 663         return error;
 664
 665 fail:
 666         aad(&sa)->label = begin_current_label_crit_section();
 667         aad(&sa)->info = name;
 668         aad(&sa)->error = error = -EINVAL;
 669         aa_audit_msg(AUDIT_APPARMOR_DENIED, &sa, NULL);
 670         end_current_label_crit_section(aad(&sa)->label);
 671         goto out;
 672 }
 673
 674 /**
 675  * apparmor_bprm_committing_creds - do task cleanup on committing new creds
 676  * @bprm: binprm for the exec  (NOT NULL)
 677  */
 678 static void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
 679 {
 680         struct aa_label *label = aa_current_raw_label();
 681         struct aa_task_ctx *new_ctx = cred_ctx(bprm->cred);
 682
 683         /* bail out if unconfined or not changing profile */
 684         if ((new_ctx->label->proxy == label->proxy) ||
 685             (unconfined(new_ctx->label)))
 686                 return;
 687
 688         aa_inherit_files(bprm->cred, current->files);
 689
 690         current->pdeath_signal = 0;
 691
 692         /* reset soft limits and set hard limits for the new label */
 693         __aa_transition_rlimits(label, new_ctx->label);
 694 }
 695
 696 /**
 697  * apparmor_bprm_committed_cred - do cleanup after new creds committed
 698  * @bprm: binprm for the exec  (NOT NULL)
 699  */
 700 static void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
 701 {
 702         /* TODO: cleanup signals - ipc mediation */
 703         return;
 704 }
 705
 706 static int apparmor_task_setrlimit(struct task_struct *task,
 707                 unsigned int resource, struct rlimit *new_rlim)
 708 {
 709         struct aa_label *label = __begin_current_label_crit_section();
 710         int error = 0;
 711
 712         if (!unconfined(label))
 713                 error = aa_task_setrlimit(label, task, resource, new_rlim);
 714         __end_current_label_crit_section(label);
 715
 716         return error;
 717 }
 718
 719 static int apparmor_task_kill(struct task_struct *target, struct siginfo *info,
 720                               int sig, u32 secid)
 721 {
 722         struct aa_label *cl, *tl;
 723         int error;
 724
 725         if (secid)
 726                 /* TODO: after secid to label mapping is done.
 727                  *  Dealing with USB IO specific behavior
 728                  */
 729                 return 0;
 730         cl = __begin_current_label_crit_section();
 731         tl = aa_get_task_label(target);
 732         error = aa_may_signal(cl, tl, sig);
 733         aa_put_label(tl);
 734         __end_current_label_crit_section(cl);
 735
 736         return error;
 737 }
 738
 739 static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
 740         LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
 741         LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
 742         LSM_HOOK_INIT(capget, apparmor_capget),
 743         LSM_HOOK_INIT(capable, apparmor_capable),
 744
 745         LSM_HOOK_INIT(sb_mount, apparmor_sb_mount),
 746         LSM_HOOK_INIT(sb_umount, apparmor_sb_umount),
 747         LSM_HOOK_INIT(sb_pivotroot, apparmor_sb_pivotroot),
 748
 749         LSM_HOOK_INIT(path_link, apparmor_path_link),
 750         LSM_HOOK_INIT(path_unlink, apparmor_path_unlink),
 751         LSM_HOOK_INIT(path_symlink, apparmor_path_symlink),
 752         LSM_HOOK_INIT(path_mkdir, apparmor_path_mkdir),
 753         LSM_HOOK_INIT(path_rmdir, apparmor_path_rmdir),
 754         LSM_HOOK_INIT(path_mknod, apparmor_path_mknod),
 755         LSM_HOOK_INIT(path_rename, apparmor_path_rename),
 756         LSM_HOOK_INIT(path_chmod, apparmor_path_chmod),
 757         LSM_HOOK_INIT(path_chown, apparmor_path_chown),
 758         LSM_HOOK_INIT(path_truncate, apparmor_path_truncate),
 759         LSM_HOOK_INIT(inode_getattr, apparmor_inode_getattr),
 760
 761         LSM_HOOK_INIT(file_open, apparmor_file_open),
 762         LSM_HOOK_INIT(file_receive, apparmor_file_receive),
 763         LSM_HOOK_INIT(file_permission, apparmor_file_permission),
 764         LSM_HOOK_INIT(file_alloc_security, apparmor_file_alloc_security),
 765         LSM_HOOK_INIT(file_free_security, apparmor_file_free_security),
 766         LSM_HOOK_INIT(mmap_file, apparmor_mmap_file),
 767         LSM_HOOK_INIT(file_mprotect, apparmor_file_mprotect),
 768         LSM_HOOK_INIT(file_lock, apparmor_file_lock),
 769
 770         LSM_HOOK_INIT(getprocattr, apparmor_getprocattr),
 771         LSM_HOOK_INIT(setprocattr, apparmor_setprocattr),
 772
 773         LSM_HOOK_INIT(cred_alloc_blank, apparmor_cred_alloc_blank),
 774         LSM_HOOK_INIT(cred_free, apparmor_cred_free),
 775         LSM_HOOK_INIT(cred_prepare, apparmor_cred_prepare),
 776         LSM_HOOK_INIT(cred_transfer, apparmor_cred_transfer),
 777
 778         LSM_HOOK_INIT(bprm_set_creds, apparmor_bprm_set_creds),
 779         LSM_HOOK_INIT(bprm_committing_creds, apparmor_bprm_committing_creds),
 780         LSM_HOOK_INIT(bprm_committed_creds, apparmor_bprm_committed_creds),
 781
 782         LSM_HOOK_INIT(task_setrlimit, apparmor_task_setrlimit),
 783         LSM_HOOK_INIT(task_kill, apparmor_task_kill),
 784 };
 785
 786 /*
 787  * AppArmor sysfs module parameters
 788  */
 789
 790 static int param_set_aabool(const char *val, const struct kernel_param *kp);
 791 static int param_get_aabool(char *buffer, const struct kernel_param *kp);
 792 #define param_check_aabool param_check_bool
 793 static const struct kernel_param_ops param_ops_aabool = {
 794         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 795         .set = param_set_aabool,
 796         .get = param_get_aabool
 797 };
 798
 799 static int param_set_aauint(const char *val, const struct kernel_param *kp);
 800 static int param_get_aauint(char *buffer, const struct kernel_param *kp);
 801 #define param_check_aauint param_check_uint
 802 static const struct kernel_param_ops param_ops_aauint = {
 803         .set = param_set_aauint,
 804         .get = param_get_aauint
 805 };
 806
 807 static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp);
 808 static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp);
 809 #define param_check_aalockpolicy param_check_bool
 810 static const struct kernel_param_ops param_ops_aalockpolicy = {
 811         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 812         .set = param_set_aalockpolicy,
 813         .get = param_get_aalockpolicy
 814 };
 815
 816 static int param_set_audit(const char *val, const struct kernel_param *kp);
 817 static int param_get_audit(char *buffer, const struct kernel_param *kp);
 818
 819 static int param_set_mode(const char *val, const struct kernel_param *kp);
 820 static int param_get_mode(char *buffer, const struct kernel_param *kp);
 821
 822 /* Flag values, also controllable via /sys/module/apparmor/parameters
 823  * We define special types as we want to do additional mediation.
 824  */
 825
 826 /* AppArmor global enforcement switch - complain, enforce, kill */
 827 enum profile_mode aa_g_profile_mode = APPARMOR_ENFORCE;
 828 module_param_call(mode, param_set_mode, param_get_mode,
 829                   &aa_g_profile_mode, S_IRUSR | S_IWUSR);
 830
 831 /* whether policy verification hashing is enabled */
 832 bool aa_g_hash_policy = IS_ENABLED(CONFIG_SECURITY_APPARMOR_HASH_DEFAULT);
 833 #ifdef CONFIG_SECURITY_APPARMOR_HASH
 834 module_param_named(hash_policy, aa_g_hash_policy, aabool, S_IRUSR | S_IWUSR);
 835 #endif
 836
 837 /* Debug mode */
 838 bool aa_g_debug = IS_ENABLED(CONFIG_SECURITY_APPARMOR_DEBUG_MESSAGES);
 839 module_param_named(debug, aa_g_debug, aabool, S_IRUSR | S_IWUSR);
 840
 841 /* Audit mode */
 842 enum audit_mode aa_g_audit;
 843 module_param_call(audit, param_set_audit, param_get_audit,
 844                   &aa_g_audit, S_IRUSR | S_IWUSR);
 845
 846 /* Determines if audit header is included in audited messages.  This
 847  * provides more context if the audit daemon is not running
 848  */
 849 bool aa_g_audit_header = true;
 850 module_param_named(audit_header, aa_g_audit_header, aabool,
 851                    S_IRUSR | S_IWUSR);
 852
 853 /* lock out loading/removal of policy
 854  * TODO: add in at boot loading of policy, which is the only way to
 855  *       load policy, if lock_policy is set
 856  */
 857 bool aa_g_lock_policy;
 858 module_param_named(lock_policy, aa_g_lock_policy, aalockpolicy,
 859                    S_IRUSR | S_IWUSR);
 860
 861 /* Syscall logging mode */
 862 bool aa_g_logsyscall;
 863 module_param_named(logsyscall, aa_g_logsyscall, aabool, S_IRUSR | S_IWUSR);
 864
 865 /* Maximum pathname length before accesses will start getting rejected */
 866 unsigned int aa_g_path_max = 2 * PATH_MAX;
 867 module_param_named(path_max, aa_g_path_max, aauint, S_IRUSR);
 868
 869 /* Determines how paranoid loading of policy is and how much verification
 870  * on the loaded policy is done.
 871  * DEPRECATED: read only as strict checking of load is always done now
 872  * that none root users (user namespaces) can load policy.
 873  */
 874 bool aa_g_paranoid_load = true;
 875 module_param_named(paranoid_load, aa_g_paranoid_load, aabool, S_IRUGO);
 876
 877 /* Boot time disable flag */
 878 static bool apparmor_enabled = CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE;
 879 module_param_named(enabled, apparmor_enabled, bool, S_IRUGO);
 880
 881 static int __init apparmor_enabled_setup(char *str)
 882 {
 883         unsigned long enabled;
 884         int error = kstrtoul(str, 0, &enabled);
 885         if (!error)
 886                 apparmor_enabled = enabled ? 1 : 0;
 887         return 1;
 888 }
 889
 890 __setup("apparmor=", apparmor_enabled_setup);
 891
 892 /* set global flag turning off the ability to load policy */
 893 static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp)
 894 {
 895         if (!apparmor_enabled)
 896                 return -EINVAL;
 897         if (apparmor_initialized && !policy_admin_capable(NULL))
 898                 return -EPERM;
 899         return param_set_bool(val, kp);
 900 }
 901
 902 static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp)
 903 {
 904         if (!apparmor_enabled)
 905                 return -EINVAL;
 906         if (apparmor_initialized && !policy_view_capable(NULL))
 907                 return -EPERM;
 908         return param_get_bool(buffer, kp);
 909 }
 910
 911 static int param_set_aabool(const char *val, const struct kernel_param *kp)
 912 {
 913         if (!apparmor_enabled)
 914                 return -EINVAL;
 915         if (apparmor_initialized && !policy_admin_capable(NULL))
 916                 return -EPERM;
 917         return param_set_bool(val, kp);
 918 }
 919
 920 static int param_get_aabool(char *buffer, const struct kernel_param *kp)
 921 {
 922         if (!apparmor_enabled)
 923                 return -EINVAL;
 924         if (apparmor_initialized && !policy_view_capable(NULL))
 925                 return -EPERM;
 926         return param_get_bool(buffer, kp);
 927 }
 928
 929 static int param_set_aauint(const char *val, const struct kernel_param *kp)
 930 {
 931         int error;
 932
 933         if (!apparmor_enabled)
 934                 return -EINVAL;
 935         /* file is ro but enforce 2nd line check */
 936         if (apparmor_initialized)
 937                 return -EPERM;
 938
 939         error = param_set_uint(val, kp);
 940         pr_info("AppArmor: buffer size set to %d bytes\n", aa_g_path_max);
 941
 942         return error;
 943 }
 944
 945 static int param_get_aauint(char *buffer, const struct kernel_param *kp)
 946 {
 947         if (!apparmor_enabled)
 948                 return -EINVAL;
 949         if (apparmor_initialized && !policy_view_capable(NULL))
 950                 return -EPERM;
 951         return param_get_uint(buffer, kp);
 952 }
 953
 954 static int param_get_audit(char *buffer, const struct kernel_param *kp)
 955 {
 956         if (!apparmor_enabled)
 957                 return -EINVAL;
 958         if (apparmor_initialized && !policy_view_capable(NULL))
 959                 return -EPERM;
 960         return sprintf(buffer, "%s", audit_mode_names[aa_g_audit]);
 961 }
 962
 963 static int param_set_audit(const char *val, const struct kernel_param *kp)
 964 {
 965         int i;
 966
 967         if (!apparmor_enabled)
 968                 return -EINVAL;
 969         if (!val)
 970                 return -EINVAL;
 971         if (apparmor_initialized && !policy_admin_capable(NULL))
 972                 return -EPERM;
 973
 974         for (i = 0; i < AUDIT_MAX_INDEX; i++) {
 975                 if (strcmp(val, audit_mode_names[i]) == 0) {
 976                         aa_g_audit = i;
 977                         return 0;
 978                 }
 979         }
 980
 981         return -EINVAL;
 982 }
 983
 984 static int param_get_mode(char *buffer, const struct kernel_param *kp)
 985 {
 986         if (!apparmor_enabled)
 987                 return -EINVAL;
 988         if (apparmor_initialized && !policy_view_capable(NULL))
 989                 return -EPERM;
 990
 991         return sprintf(buffer, "%s", aa_profile_mode_names[aa_g_profile_mode]);
 992 }
 993
 994 static int param_set_mode(const char *val, const struct kernel_param *kp)
 995 {
 996         int i;
 997
 998         if (!apparmor_enabled)
 999                 return -EINVAL;
1000         if (!val)
1001                 return -EINVAL;
1002         if (apparmor_initialized && !policy_admin_capable(NULL))
1003                 return -EPERM;
1004
1005         for (i = 0; i < APPARMOR_MODE_NAMES_MAX_INDEX; i++) {
1006                 if (strcmp(val, aa_profile_mode_names[i]) == 0) {
1007                         aa_g_profile_mode = i;
1008                         return 0;
1009                 }
1010         }
1011
1012         return -EINVAL;
1013 }
1014
1015 /*
1016  * AppArmor init functions
1017  */
1018
1019 /**
1020  * set_init_ctx - set a task context and profile on the first task.
1021  *
1022  * TODO: allow setting an alternate profile than unconfined
1023  */
1024 static int __init set_init_ctx(void)
1025 {
1026         struct cred *cred = (struct cred *)current->real_cred;
1027         struct aa_task_ctx *ctx;
1028
1029         ctx = aa_alloc_task_context(GFP_KERNEL);
1030         if (!ctx)
1031                 return -ENOMEM;
1032
1033         ctx->label = aa_get_label(ns_unconfined(root_ns));
1034         cred_ctx(cred) = ctx;
1035
1036         return 0;
1037 }
1038
1039 static void destroy_buffers(void)
1040 {
1041         u32 i, j;
1042
1043         for_each_possible_cpu(i) {
1044                 for_each_cpu_buffer(j) {
1045                         kfree(per_cpu(aa_buffers, i).buf[j]);
1046                         per_cpu(aa_buffers, i).buf[j] = NULL;
1047                 }
1048         }
1049 }
1050
1051 static int __init alloc_buffers(void)
1052 {
1053         u32 i, j;
1054
1055         for_each_possible_cpu(i) {
1056                 for_each_cpu_buffer(j) {
1057                         char *buffer;
1058
1059                         if (cpu_to_node(i) > num_online_nodes())
1060                                 /* fallback to kmalloc for offline nodes */
1061                                 buffer = kmalloc(aa_g_path_max, GFP_KERNEL);
1062                         else
1063                                 buffer = kmalloc_node(aa_g_path_max, GFP_KERNEL,
1064                                                       cpu_to_node(i));
1065                         if (!buffer) {
1066                                 destroy_buffers();
1067                                 return -ENOMEM;
1068                         }
1069                         per_cpu(aa_buffers, i).buf[j] = buffer;
1070                 }
1071         }
1072
1073         return 0;
1074 }
1075
1076 #ifdef CONFIG_SYSCTL
1077 static int apparmor_dointvec(struct ctl_table *table, int write,
1078                              void __user *buffer, size_t *lenp, loff_t *ppos)
1079 {
1080         if (!policy_admin_capable(NULL))
1081                 return -EPERM;
1082         if (!apparmor_enabled)
1083                 return -EINVAL;
1084
1085         return proc_dointvec(table, write, buffer, lenp, ppos);
1086 }
1087
1088 static struct ctl_path apparmor_sysctl_path[] = {
1089         { .procname = "kernel", },
1090         { }
1091 };
1092
1093 static struct ctl_table apparmor_sysctl_table[] = {
1094         {
1095                 .procname       = "unprivileged_userns_apparmor_policy",
1096                 .data           = &unprivileged_userns_apparmor_policy,
1097                 .maxlen         = sizeof(int),
1098                 .mode           = 0600,
1099                 .proc_handler   = apparmor_dointvec,
1100         },
1101         { }
1102 };
1103
1104 static int __init apparmor_init_sysctl(void)
1105 {
1106         return register_sysctl_paths(apparmor_sysctl_path,
1107                                      apparmor_sysctl_table) ? 0 : -ENOMEM;
1108 }
1109 #else
1110 static inline int apparmor_init_sysctl(void)
1111 {
1112         return 0;
1113 }
1114 #endif /* CONFIG_SYSCTL */
1115
1116 static int __init apparmor_init(void)
1117 {
1118         int error;
1119
1120         if (!apparmor_enabled || !security_module_enable("apparmor")) {
1121                 aa_info_message("AppArmor disabled by boot time parameter");
1122                 apparmor_enabled = false;
1123                 return 0;
1124         }
1125
1126         error = aa_setup_dfa_engine();
1127         if (error) {
1128                 AA_ERROR("Unable to setup dfa engine\n");
1129                 goto alloc_out;
1130         }
1131
1132         error = aa_alloc_root_ns();
1133         if (error) {
1134                 AA_ERROR("Unable to allocate default profile namespace\n");
1135                 goto alloc_out;
1136         }
1137
1138         error = apparmor_init_sysctl();
1139         if (error) {
1140                 AA_ERROR("Unable to register sysctls\n");
1141                 goto alloc_out;
1142
1143         }
1144
1145         error = alloc_buffers();
1146         if (error) {
1147                 AA_ERROR("Unable to allocate work buffers\n");
1148                 goto buffers_out;
1149         }
1150
1151         error = set_init_ctx();
1152         if (error) {
1153                 AA_ERROR("Failed to set context on init task\n");
1154                 aa_free_root_ns();
1155                 goto buffers_out;
1156         }
1157         security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks),
1158                                 "apparmor");
1159
1160         /* Report that AppArmor successfully initialized */
1161         apparmor_initialized = 1;
1162         if (aa_g_profile_mode == APPARMOR_COMPLAIN)
1163                 aa_info_message("AppArmor initialized: complain mode enabled");
1164         else if (aa_g_profile_mode == APPARMOR_KILL)
1165                 aa_info_message("AppArmor initialized: kill mode enabled");
1166         else
1167                 aa_info_message("AppArmor initialized");
1168
1169         return error;
1170
1171 buffers_out:
1172         destroy_buffers();
1173
1174 alloc_out:
1175         aa_destroy_aafs();
1176         aa_teardown_dfa_engine();
1177
1178         apparmor_enabled = false;
1179         return error;
1180 }
1181
1182 security_initcall(apparmor_init);