1 /* 2 * Simplified MAC Kernel (smack) security module 3 * 4 * This file contains the smack hook function implementations. 5 * 6 * Authors: 7 * Casey Schaufler <casey@schaufler-ca.com> 8 * Jarkko Sakkinen <jarkko.sakkinen@intel.com> 9 * 10 * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com> 11 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P. 12 * Paul Moore <paul@paul-moore.com> 13 * Copyright (C) 2010 Nokia Corporation 14 * Copyright (C) 2011 Intel Corporation. 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License version 2, 18 * as published by the Free Software Foundation. 19 */ 20 21 #include <linux/xattr.h> 22 #include <linux/pagemap.h> 23 #include <linux/mount.h> 24 #include <linux/stat.h> 25 #include <linux/kd.h> 26 #include <asm/ioctls.h> 27 #include <linux/ip.h> 28 #include <linux/tcp.h> 29 #include <linux/udp.h> 30 #include <linux/slab.h> 31 #include <linux/mutex.h> 32 #include <linux/pipe_fs_i.h> 33 #include <net/cipso_ipv4.h> 34 #include <linux/audit.h> 35 #include <linux/magic.h> 36 #include <linux/dcache.h> 37 #include <linux/personality.h> 38 #include <linux/msg.h> 39 #include <linux/shm.h> 40 #include <linux/binfmts.h> 41 #include "smack.h" 42 43 #define task_security(task) (task_cred_xxx((task), security)) 44 45 #define TRANS_TRUE "TRUE" 46 #define TRANS_TRUE_SIZE 4 47 48 /** 49 * smk_fetch - Fetch the smack label from a file. 50 * @ip: a pointer to the inode 51 * @dp: a pointer to the dentry 52 * 53 * Returns a pointer to the master list entry for the Smack label 54 * or NULL if there was no label to fetch. 55 */ 56 static char *smk_fetch(const char *name, struct inode *ip, struct dentry *dp) 57 { 58 int rc; 59 char *buffer; 60 char *result = NULL; 61 62 if (ip->i_op->getxattr == NULL) 63 return NULL; 64 65 buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL); 66 if (buffer == NULL) 67 return NULL; 68 69 rc = ip->i_op->getxattr(dp, name, buffer, SMK_LONGLABEL); 70 if (rc > 0) 71 result = smk_import(buffer, rc); 72 73 kfree(buffer); 74 75 return result; 76 } 77 78 /** 79 * new_inode_smack - allocate an inode security blob 80 * @smack: a pointer to the Smack label to use in the blob 81 * 82 * Returns the new blob or NULL if there's no memory available 83 */ 84 struct inode_smack *new_inode_smack(char *smack) 85 { 86 struct inode_smack *isp; 87 88 isp = kzalloc(sizeof(struct inode_smack), GFP_NOFS); 89 if (isp == NULL) 90 return NULL; 91 92 isp->smk_inode = smack; 93 isp->smk_flags = 0; 94 mutex_init(&isp->smk_lock); 95 96 return isp; 97 } 98 99 /** 100 * new_task_smack - allocate a task security blob 101 * @smack: a pointer to the Smack label to use in the blob 102 * 103 * Returns the new blob or NULL if there's no memory available 104 */ 105 static struct task_smack *new_task_smack(char *task, char *forked, gfp_t gfp) 106 { 107 struct task_smack *tsp; 108 109 tsp = kzalloc(sizeof(struct task_smack), gfp); 110 if (tsp == NULL) 111 return NULL; 112 113 tsp->smk_task = task; 114 tsp->smk_forked = forked; 115 INIT_LIST_HEAD(&tsp->smk_rules); 116 mutex_init(&tsp->smk_rules_lock); 117 118 return tsp; 119 } 120 121 /** 122 * smk_copy_rules - copy a rule set 123 * @nhead - new rules header pointer 124 * @ohead - old rules header pointer 125 * 126 * Returns 0 on success, -ENOMEM on error 127 */ 128 static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead, 129 gfp_t gfp) 130 { 131 struct smack_rule *nrp; 132 struct smack_rule *orp; 133 int rc = 0; 134 135 INIT_LIST_HEAD(nhead); 136 137 list_for_each_entry_rcu(orp, ohead, list) { 138 nrp = kzalloc(sizeof(struct smack_rule), gfp); 139 if (nrp == NULL) { 140 rc = -ENOMEM; 141 break; 142 } 143 *nrp = *orp; 144 list_add_rcu(&nrp->list, nhead); 145 } 146 return rc; 147 } 148 149 /* 150 * LSM hooks. 151 * We he, that is fun! 152 */ 153 154 /** 155 * smack_ptrace_access_check - Smack approval on PTRACE_ATTACH 156 * @ctp: child task pointer 157 * @mode: ptrace attachment mode 158 * 159 * Returns 0 if access is OK, an error code otherwise 160 * 161 * Do the capability checks, and require read and write. 162 */ 163 static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode) 164 { 165 int rc; 166 struct smk_audit_info ad; 167 char *tsp; 168 169 rc = cap_ptrace_access_check(ctp, mode); 170 if (rc != 0) 171 return rc; 172 173 tsp = smk_of_task(task_security(ctp)); 174 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); 175 smk_ad_setfield_u_tsk(&ad, ctp); 176 177 rc = smk_curacc(tsp, MAY_READWRITE, &ad); 178 return rc; 179 } 180 181 /** 182 * smack_ptrace_traceme - Smack approval on PTRACE_TRACEME 183 * @ptp: parent task pointer 184 * 185 * Returns 0 if access is OK, an error code otherwise 186 * 187 * Do the capability checks, and require read and write. 188 */ 189 static int smack_ptrace_traceme(struct task_struct *ptp) 190 { 191 int rc; 192 struct smk_audit_info ad; 193 char *tsp; 194 195 rc = cap_ptrace_traceme(ptp); 196 if (rc != 0) 197 return rc; 198 199 tsp = smk_of_task(task_security(ptp)); 200 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); 201 smk_ad_setfield_u_tsk(&ad, ptp); 202 203 rc = smk_curacc(tsp, MAY_READWRITE, &ad); 204 return rc; 205 } 206 207 /** 208 * smack_syslog - Smack approval on syslog 209 * @type: message type 210 * 211 * Require that the task has the floor label 212 * 213 * Returns 0 on success, error code otherwise. 214 */ 215 static int smack_syslog(int typefrom_file) 216 { 217 int rc = 0; 218 char *sp = smk_of_current(); 219 220 if (capable(CAP_MAC_OVERRIDE)) 221 return 0; 222 223 if (sp != smack_known_floor.smk_known) 224 rc = -EACCES; 225 226 return rc; 227 } 228 229 230 /* 231 * Superblock Hooks. 232 */ 233 234 /** 235 * smack_sb_alloc_security - allocate a superblock blob 236 * @sb: the superblock getting the blob 237 * 238 * Returns 0 on success or -ENOMEM on error. 239 */ 240 static int smack_sb_alloc_security(struct super_block *sb) 241 { 242 struct superblock_smack *sbsp; 243 244 sbsp = kzalloc(sizeof(struct superblock_smack), GFP_KERNEL); 245 246 if (sbsp == NULL) 247 return -ENOMEM; 248 249 sbsp->smk_root = smack_known_floor.smk_known; 250 sbsp->smk_default = smack_known_floor.smk_known; 251 sbsp->smk_floor = smack_known_floor.smk_known; 252 sbsp->smk_hat = smack_known_hat.smk_known; 253 sbsp->smk_initialized = 0; 254 spin_lock_init(&sbsp->smk_sblock); 255 256 sb->s_security = sbsp; 257 258 return 0; 259 } 260 261 /** 262 * smack_sb_free_security - free a superblock blob 263 * @sb: the superblock getting the blob 264 * 265 */ 266 static void smack_sb_free_security(struct super_block *sb) 267 { 268 kfree(sb->s_security); 269 sb->s_security = NULL; 270 } 271 272 /** 273 * smack_sb_copy_data - copy mount options data for processing 274 * @orig: where to start 275 * @smackopts: mount options string 276 * 277 * Returns 0 on success or -ENOMEM on error. 278 * 279 * Copy the Smack specific mount options out of the mount 280 * options list. 281 */ 282 static int smack_sb_copy_data(char *orig, char *smackopts) 283 { 284 char *cp, *commap, *otheropts, *dp; 285 286 otheropts = (char *)get_zeroed_page(GFP_KERNEL); 287 if (otheropts == NULL) 288 return -ENOMEM; 289 290 for (cp = orig, commap = orig; commap != NULL; cp = commap + 1) { 291 if (strstr(cp, SMK_FSDEFAULT) == cp) 292 dp = smackopts; 293 else if (strstr(cp, SMK_FSFLOOR) == cp) 294 dp = smackopts; 295 else if (strstr(cp, SMK_FSHAT) == cp) 296 dp = smackopts; 297 else if (strstr(cp, SMK_FSROOT) == cp) 298 dp = smackopts; 299 else 300 dp = otheropts; 301 302 commap = strchr(cp, ','); 303 if (commap != NULL) 304 *commap = '\0'; 305 306 if (*dp != '\0') 307 strcat(dp, ","); 308 strcat(dp, cp); 309 } 310 311 strcpy(orig, otheropts); 312 free_page((unsigned long)otheropts); 313 314 return 0; 315 } 316 317 /** 318 * smack_sb_kern_mount - Smack specific mount processing 319 * @sb: the file system superblock 320 * @flags: the mount flags 321 * @data: the smack mount options 322 * 323 * Returns 0 on success, an error code on failure 324 */ 325 static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data) 326 { 327 struct dentry *root = sb->s_root; 328 struct inode *inode = root->d_inode; 329 struct superblock_smack *sp = sb->s_security; 330 struct inode_smack *isp; 331 char *op; 332 char *commap; 333 char *nsp; 334 335 spin_lock(&sp->smk_sblock); 336 if (sp->smk_initialized != 0) { 337 spin_unlock(&sp->smk_sblock); 338 return 0; 339 } 340 sp->smk_initialized = 1; 341 spin_unlock(&sp->smk_sblock); 342 343 for (op = data; op != NULL; op = commap) { 344 commap = strchr(op, ','); 345 if (commap != NULL) 346 *commap++ = '\0'; 347 348 if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) { 349 op += strlen(SMK_FSHAT); 350 nsp = smk_import(op, 0); 351 if (nsp != NULL) 352 sp->smk_hat = nsp; 353 } else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) { 354 op += strlen(SMK_FSFLOOR); 355 nsp = smk_import(op, 0); 356 if (nsp != NULL) 357 sp->smk_floor = nsp; 358 } else if (strncmp(op, SMK_FSDEFAULT, 359 strlen(SMK_FSDEFAULT)) == 0) { 360 op += strlen(SMK_FSDEFAULT); 361 nsp = smk_import(op, 0); 362 if (nsp != NULL) 363 sp->smk_default = nsp; 364 } else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) { 365 op += strlen(SMK_FSROOT); 366 nsp = smk_import(op, 0); 367 if (nsp != NULL) 368 sp->smk_root = nsp; 369 } 370 } 371 372 /* 373 * Initialize the root inode. 374 */ 375 isp = inode->i_security; 376 if (isp == NULL) 377 inode->i_security = new_inode_smack(sp->smk_root); 378 else 379 isp->smk_inode = sp->smk_root; 380 381 return 0; 382 } 383 384 /** 385 * smack_sb_statfs - Smack check on statfs 386 * @dentry: identifies the file system in question 387 * 388 * Returns 0 if current can read the floor of the filesystem, 389 * and error code otherwise 390 */ 391 static int smack_sb_statfs(struct dentry *dentry) 392 { 393 struct superblock_smack *sbp = dentry->d_sb->s_security; 394 int rc; 395 struct smk_audit_info ad; 396 397 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); 398 smk_ad_setfield_u_fs_path_dentry(&ad, dentry); 399 400 rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad); 401 return rc; 402 } 403 404 /** 405 * smack_sb_mount - Smack check for mounting 406 * @dev_name: unused 407 * @path: mount point 408 * @type: unused 409 * @flags: unused 410 * @data: unused 411 * 412 * Returns 0 if current can write the floor of the filesystem 413 * being mounted on, an error code otherwise. 414 */ 415 static int smack_sb_mount(char *dev_name, struct path *path, 416 char *type, unsigned long flags, void *data) 417 { 418 struct superblock_smack *sbp = path->dentry->d_sb->s_security; 419 struct smk_audit_info ad; 420 421 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); 422 smk_ad_setfield_u_fs_path(&ad, *path); 423 424 return smk_curacc(sbp->smk_floor, MAY_WRITE, &ad); 425 } 426 427 /** 428 * smack_sb_umount - Smack check for unmounting 429 * @mnt: file system to unmount 430 * @flags: unused 431 * 432 * Returns 0 if current can write the floor of the filesystem 433 * being unmounted, an error code otherwise. 434 */ 435 static int smack_sb_umount(struct vfsmount *mnt, int flags) 436 { 437 struct superblock_smack *sbp; 438 struct smk_audit_info ad; 439 struct path path; 440 441 path.dentry = mnt->mnt_root; 442 path.mnt = mnt; 443 444 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); 445 smk_ad_setfield_u_fs_path(&ad, path); 446 447 sbp = path.dentry->d_sb->s_security; 448 return smk_curacc(sbp->smk_floor, MAY_WRITE, &ad); 449 } 450 451 /* 452 * BPRM hooks 453 */ 454 455 /** 456 * smack_bprm_set_creds - set creds for exec 457 * @bprm: the exec information 458 * 459 * Returns 0 if it gets a blob, -ENOMEM otherwise 460 */ 461 static int smack_bprm_set_creds(struct linux_binprm *bprm) 462 { 463 struct inode *inode = bprm->file->f_path.dentry->d_inode; 464 struct task_smack *bsp = bprm->cred->security; 465 struct inode_smack *isp; 466 int rc; 467 468 rc = cap_bprm_set_creds(bprm); 469 if (rc != 0) 470 return rc; 471 472 if (bprm->cred_prepared) 473 return 0; 474 475 isp = inode->i_security; 476 if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task) 477 return 0; 478 479 if (bprm->unsafe) 480 return -EPERM; 481 482 bsp->smk_task = isp->smk_task; 483 bprm->per_clear |= PER_CLEAR_ON_SETID; 484 485 return 0; 486 } 487 488 /** 489 * smack_bprm_committing_creds - Prepare to install the new credentials 490 * from bprm. 491 * 492 * @bprm: binprm for exec 493 */ 494 static void smack_bprm_committing_creds(struct linux_binprm *bprm) 495 { 496 struct task_smack *bsp = bprm->cred->security; 497 498 if (bsp->smk_task != bsp->smk_forked) 499 current->pdeath_signal = 0; 500 } 501 502 /** 503 * smack_bprm_secureexec - Return the decision to use secureexec. 504 * @bprm: binprm for exec 505 * 506 * Returns 0 on success. 507 */ 508 static int smack_bprm_secureexec(struct linux_binprm *bprm) 509 { 510 struct task_smack *tsp = current_security(); 511 int ret = cap_bprm_secureexec(bprm); 512 513 if (!ret && (tsp->smk_task != tsp->smk_forked)) 514 ret = 1; 515 516 return ret; 517 } 518 519 /* 520 * Inode hooks 521 */ 522 523 /** 524 * smack_inode_alloc_security - allocate an inode blob 525 * @inode: the inode in need of a blob 526 * 527 * Returns 0 if it gets a blob, -ENOMEM otherwise 528 */ 529 static int smack_inode_alloc_security(struct inode *inode) 530 { 531 inode->i_security = new_inode_smack(smk_of_current()); 532 if (inode->i_security == NULL) 533 return -ENOMEM; 534 return 0; 535 } 536 537 /** 538 * smack_inode_free_security - free an inode blob 539 * @inode: the inode with a blob 540 * 541 * Clears the blob pointer in inode 542 */ 543 static void smack_inode_free_security(struct inode *inode) 544 { 545 kfree(inode->i_security); 546 inode->i_security = NULL; 547 } 548 549 /** 550 * smack_inode_init_security - copy out the smack from an inode 551 * @inode: the inode 552 * @dir: unused 553 * @qstr: unused 554 * @name: where to put the attribute name 555 * @value: where to put the attribute value 556 * @len: where to put the length of the attribute 557 * 558 * Returns 0 if it all works out, -ENOMEM if there's no memory 559 */ 560 static int smack_inode_init_security(struct inode *inode, struct inode *dir, 561 const struct qstr *qstr, char **name, 562 void **value, size_t *len) 563 { 564 struct smack_known *skp; 565 struct inode_smack *issp = inode->i_security; 566 char *csp = smk_of_current(); 567 char *isp = smk_of_inode(inode); 568 char *dsp = smk_of_inode(dir); 569 int may; 570 571 if (name) { 572 *name = kstrdup(XATTR_SMACK_SUFFIX, GFP_NOFS); 573 if (*name == NULL) 574 return -ENOMEM; 575 } 576 577 if (value) { 578 skp = smk_find_entry(csp); 579 rcu_read_lock(); 580 may = smk_access_entry(csp, dsp, &skp->smk_rules); 581 rcu_read_unlock(); 582 583 /* 584 * If the access rule allows transmutation and 585 * the directory requests transmutation then 586 * by all means transmute. 587 * Mark the inode as changed. 588 */ 589 if (may > 0 && ((may & MAY_TRANSMUTE) != 0) && 590 smk_inode_transmutable(dir)) { 591 isp = dsp; 592 issp->smk_flags |= SMK_INODE_CHANGED; 593 } 594 595 *value = kstrdup(isp, GFP_NOFS); 596 if (*value == NULL) 597 return -ENOMEM; 598 } 599 600 if (len) 601 *len = strlen(isp) + 1; 602 603 return 0; 604 } 605 606 /** 607 * smack_inode_link - Smack check on link 608 * @old_dentry: the existing object 609 * @dir: unused 610 * @new_dentry: the new object 611 * 612 * Returns 0 if access is permitted, an error code otherwise 613 */ 614 static int smack_inode_link(struct dentry *old_dentry, struct inode *dir, 615 struct dentry *new_dentry) 616 { 617 char *isp; 618 struct smk_audit_info ad; 619 int rc; 620 621 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); 622 smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry); 623 624 isp = smk_of_inode(old_dentry->d_inode); 625 rc = smk_curacc(isp, MAY_WRITE, &ad); 626 627 if (rc == 0 && new_dentry->d_inode != NULL) { 628 isp = smk_of_inode(new_dentry->d_inode); 629 smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry); 630 rc = smk_curacc(isp, MAY_WRITE, &ad); 631 } 632 633 return rc; 634 } 635 636 /** 637 * smack_inode_unlink - Smack check on inode deletion 638 * @dir: containing directory object 639 * @dentry: file to unlink 640 * 641 * Returns 0 if current can write the containing directory 642 * and the object, error code otherwise 643 */ 644 static int smack_inode_unlink(struct inode *dir, struct dentry *dentry) 645 { 646 struct inode *ip = dentry->d_inode; 647 struct smk_audit_info ad; 648 int rc; 649 650 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); 651 smk_ad_setfield_u_fs_path_dentry(&ad, dentry); 652 653 /* 654 * You need write access to the thing you're unlinking 655 */ 656 rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad); 657 if (rc == 0) { 658 /* 659 * You also need write access to the containing directory 660 */ 661 smk_ad_setfield_u_fs_path_dentry(&ad, NULL); 662 smk_ad_setfield_u_fs_inode(&ad, dir); 663 rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad); 664 } 665 return rc; 666 } 667 668 /** 669 * smack_inode_rmdir - Smack check on directory deletion 670 * @dir: containing directory object 671 * @dentry: directory to unlink 672 * 673 * Returns 0 if current can write the containing directory 674 * and the directory, error code otherwise 675 */ 676 static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry) 677 { 678 struct smk_audit_info ad; 679 int rc; 680 681 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); 682 smk_ad_setfield_u_fs_path_dentry(&ad, dentry); 683 684 /* 685 * You need write access to the thing you're removing 686 */ 687 rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad); 688 if (rc == 0) { 689 /* 690 * You also need write access to the containing directory 691 */ 692 smk_ad_setfield_u_fs_path_dentry(&ad, NULL); 693 smk_ad_setfield_u_fs_inode(&ad, dir); 694 rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad); 695 } 696 697 return rc; 698 } 699 700 /** 701 * smack_inode_rename - Smack check on rename 702 * @old_inode: the old directory 703 * @old_dentry: unused 704 * @new_inode: the new directory 705 * @new_dentry: unused 706 * 707 * Read and write access is required on both the old and 708 * new directories. 709 * 710 * Returns 0 if access is permitted, an error code otherwise 711 */ 712 static int smack_inode_rename(struct inode *old_inode, 713 struct dentry *old_dentry, 714 struct inode *new_inode, 715 struct dentry *new_dentry) 716 { 717 int rc; 718 char *isp; 719 struct smk_audit_info ad; 720 721 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); 722 smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry); 723 724 isp = smk_of_inode(old_dentry->d_inode); 725 rc = smk_curacc(isp, MAY_READWRITE, &ad); 726 727 if (rc == 0 && new_dentry->d_inode != NULL) { 728 isp = smk_of_inode(new_dentry->d_inode); 729 smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry); 730 rc = smk_curacc(isp, MAY_READWRITE, &ad); 731 } 732 return rc; 733 } 734 735 /** 736 * smack_inode_permission - Smack version of permission() 737 * @inode: the inode in question 738 * @mask: the access requested 739 * 740 * This is the important Smack hook. 741 * 742 * Returns 0 if access is permitted, -EACCES otherwise 743 */ 744 static int smack_inode_permission(struct inode *inode, int mask) 745 { 746 struct smk_audit_info ad; 747 int no_block = mask & MAY_NOT_BLOCK; 748 749 mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND); 750 /* 751 * No permission to check. Existence test. Yup, it's there. 752 */ 753 if (mask == 0) 754 return 0; 755 756 /* May be droppable after audit */ 757 if (no_block) 758 return -ECHILD; 759 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE); 760 smk_ad_setfield_u_fs_inode(&ad, inode); 761 return smk_curacc(smk_of_inode(inode), mask, &ad); 762 } 763 764 /** 765 * smack_inode_setattr - Smack check for setting attributes 766 * @dentry: the object 767 * @iattr: for the force flag 768 * 769 * Returns 0 if access is permitted, an error code otherwise 770 */ 771 static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr) 772 { 773 struct smk_audit_info ad; 774 /* 775 * Need to allow for clearing the setuid bit. 776 */ 777 if (iattr->ia_valid & ATTR_FORCE) 778 return 0; 779 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); 780 smk_ad_setfield_u_fs_path_dentry(&ad, dentry); 781 782 return smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad); 783 } 784 785 /** 786 * smack_inode_getattr - Smack check for getting attributes 787 * @mnt: unused 788 * @dentry: the object 789 * 790 * Returns 0 if access is permitted, an error code otherwise 791 */ 792 static int smack_inode_getattr(struct vfsmount *mnt, struct dentry *dentry) 793 { 794 struct smk_audit_info ad; 795 struct path path; 796 797 path.dentry = dentry; 798 path.mnt = mnt; 799 800 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); 801 smk_ad_setfield_u_fs_path(&ad, path); 802 return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad); 803 } 804 805 /** 806 * smack_inode_setxattr - Smack check for setting xattrs 807 * @dentry: the object 808 * @name: name of the attribute 809 * @value: unused 810 * @size: unused 811 * @flags: unused 812 * 813 * This protects the Smack attribute explicitly. 814 * 815 * Returns 0 if access is permitted, an error code otherwise 816 */ 817 static int smack_inode_setxattr(struct dentry *dentry, const char *name, 818 const void *value, size_t size, int flags) 819 { 820 struct smk_audit_info ad; 821 int rc = 0; 822 823 if (strcmp(name, XATTR_NAME_SMACK) == 0 || 824 strcmp(name, XATTR_NAME_SMACKIPIN) == 0 || 825 strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 || 826 strcmp(name, XATTR_NAME_SMACKEXEC) == 0 || 827 strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { 828 if (!capable(CAP_MAC_ADMIN)) 829 rc = -EPERM; 830 /* 831 * check label validity here so import wont fail on 832 * post_setxattr 833 */ 834 if (size == 0 || size >= SMK_LONGLABEL || 835 smk_import(value, size) == NULL) 836 rc = -EINVAL; 837 } else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) { 838 if (!capable(CAP_MAC_ADMIN)) 839 rc = -EPERM; 840 if (size != TRANS_TRUE_SIZE || 841 strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0) 842 rc = -EINVAL; 843 } else 844 rc = cap_inode_setxattr(dentry, name, value, size, flags); 845 846 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); 847 smk_ad_setfield_u_fs_path_dentry(&ad, dentry); 848 849 if (rc == 0) 850 rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad); 851 852 return rc; 853 } 854 855 /** 856 * smack_inode_post_setxattr - Apply the Smack update approved above 857 * @dentry: object 858 * @name: attribute name 859 * @value: attribute value 860 * @size: attribute size 861 * @flags: unused 862 * 863 * Set the pointer in the inode blob to the entry found 864 * in the master label list. 865 */ 866 static void smack_inode_post_setxattr(struct dentry *dentry, const char *name, 867 const void *value, size_t size, int flags) 868 { 869 char *nsp; 870 struct inode_smack *isp = dentry->d_inode->i_security; 871 872 if (strcmp(name, XATTR_NAME_SMACK) == 0) { 873 nsp = smk_import(value, size); 874 if (nsp != NULL) 875 isp->smk_inode = nsp; 876 else 877 isp->smk_inode = smack_known_invalid.smk_known; 878 } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) { 879 nsp = smk_import(value, size); 880 if (nsp != NULL) 881 isp->smk_task = nsp; 882 else 883 isp->smk_task = smack_known_invalid.smk_known; 884 } else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { 885 nsp = smk_import(value, size); 886 if (nsp != NULL) 887 isp->smk_mmap = nsp; 888 else 889 isp->smk_mmap = smack_known_invalid.smk_known; 890 } else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) 891 isp->smk_flags |= SMK_INODE_TRANSMUTE; 892 893 return; 894 } 895 896 /** 897 * smack_inode_getxattr - Smack check on getxattr 898 * @dentry: the object 899 * @name: unused 900 * 901 * Returns 0 if access is permitted, an error code otherwise 902 */ 903 static int smack_inode_getxattr(struct dentry *dentry, const char *name) 904 { 905 struct smk_audit_info ad; 906 907 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); 908 smk_ad_setfield_u_fs_path_dentry(&ad, dentry); 909 910 return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad); 911 } 912 913 /** 914 * smack_inode_removexattr - Smack check on removexattr 915 * @dentry: the object 916 * @name: name of the attribute 917 * 918 * Removing the Smack attribute requires CAP_MAC_ADMIN 919 * 920 * Returns 0 if access is permitted, an error code otherwise 921 */ 922 static int smack_inode_removexattr(struct dentry *dentry, const char *name) 923 { 924 struct inode_smack *isp; 925 struct smk_audit_info ad; 926 int rc = 0; 927 928 if (strcmp(name, XATTR_NAME_SMACK) == 0 || 929 strcmp(name, XATTR_NAME_SMACKIPIN) == 0 || 930 strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 || 931 strcmp(name, XATTR_NAME_SMACKEXEC) == 0 || 932 strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 || 933 strcmp(name, XATTR_NAME_SMACKMMAP)) { 934 if (!capable(CAP_MAC_ADMIN)) 935 rc = -EPERM; 936 } else 937 rc = cap_inode_removexattr(dentry, name); 938 939 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); 940 smk_ad_setfield_u_fs_path_dentry(&ad, dentry); 941 if (rc == 0) 942 rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad); 943 944 if (rc == 0) { 945 isp = dentry->d_inode->i_security; 946 isp->smk_task = NULL; 947 isp->smk_mmap = NULL; 948 } 949 950 return rc; 951 } 952 953 /** 954 * smack_inode_getsecurity - get smack xattrs 955 * @inode: the object 956 * @name: attribute name 957 * @buffer: where to put the result 958 * @alloc: unused 959 * 960 * Returns the size of the attribute or an error code 961 */ 962 static int smack_inode_getsecurity(const struct inode *inode, 963 const char *name, void **buffer, 964 bool alloc) 965 { 966 struct socket_smack *ssp; 967 struct socket *sock; 968 struct super_block *sbp; 969 struct inode *ip = (struct inode *)inode; 970 char *isp; 971 int ilen; 972 int rc = 0; 973 974 if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) { 975 isp = smk_of_inode(inode); 976 ilen = strlen(isp) + 1; 977 *buffer = isp; 978 return ilen; 979 } 980 981 /* 982 * The rest of the Smack xattrs are only on sockets. 983 */ 984 sbp = ip->i_sb; 985 if (sbp->s_magic != SOCKFS_MAGIC) 986 return -EOPNOTSUPP; 987 988 sock = SOCKET_I(ip); 989 if (sock == NULL || sock->sk == NULL) 990 return -EOPNOTSUPP; 991 992 ssp = sock->sk->sk_security; 993 994 if (strcmp(name, XATTR_SMACK_IPIN) == 0) 995 isp = ssp->smk_in; 996 else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) 997 isp = ssp->smk_out; 998 else 999 return -EOPNOTSUPP; 1000 1001 ilen = strlen(isp) + 1; 1002 if (rc == 0) { 1003 *buffer = isp; 1004 rc = ilen; 1005 } 1006 1007 return rc; 1008 } 1009 1010 1011 /** 1012 * smack_inode_listsecurity - list the Smack attributes 1013 * @inode: the object 1014 * @buffer: where they go 1015 * @buffer_size: size of buffer 1016 * 1017 * Returns 0 on success, -EINVAL otherwise 1018 */ 1019 static int smack_inode_listsecurity(struct inode *inode, char *buffer, 1020 size_t buffer_size) 1021 { 1022 int len = strlen(XATTR_NAME_SMACK); 1023 1024 if (buffer != NULL && len <= buffer_size) { 1025 memcpy(buffer, XATTR_NAME_SMACK, len); 1026 return len; 1027 } 1028 return -EINVAL; 1029 } 1030 1031 /** 1032 * smack_inode_getsecid - Extract inode's security id 1033 * @inode: inode to extract the info from 1034 * @secid: where result will be saved 1035 */ 1036 static void smack_inode_getsecid(const struct inode *inode, u32 *secid) 1037 { 1038 struct inode_smack *isp = inode->i_security; 1039 1040 *secid = smack_to_secid(isp->smk_inode); 1041 } 1042 1043 /* 1044 * File Hooks 1045 */ 1046 1047 /** 1048 * smack_file_permission - Smack check on file operations 1049 * @file: unused 1050 * @mask: unused 1051 * 1052 * Returns 0 1053 * 1054 * Should access checks be done on each read or write? 1055 * UNICOS and SELinux say yes. 1056 * Trusted Solaris, Trusted Irix, and just about everyone else says no. 1057 * 1058 * I'll say no for now. Smack does not do the frequent 1059 * label changing that SELinux does. 1060 */ 1061 static int smack_file_permission(struct file *file, int mask) 1062 { 1063 return 0; 1064 } 1065 1066 /** 1067 * smack_file_alloc_security - assign a file security blob 1068 * @file: the object 1069 * 1070 * The security blob for a file is a pointer to the master 1071 * label list, so no allocation is done. 1072 * 1073 * Returns 0 1074 */ 1075 static int smack_file_alloc_security(struct file *file) 1076 { 1077 file->f_security = smk_of_current(); 1078 return 0; 1079 } 1080 1081 /** 1082 * smack_file_free_security - clear a file security blob 1083 * @file: the object 1084 * 1085 * The security blob for a file is a pointer to the master 1086 * label list, so no memory is freed. 1087 */ 1088 static void smack_file_free_security(struct file *file) 1089 { 1090 file->f_security = NULL; 1091 } 1092 1093 /** 1094 * smack_file_ioctl - Smack check on ioctls 1095 * @file: the object 1096 * @cmd: what to do 1097 * @arg: unused 1098 * 1099 * Relies heavily on the correct use of the ioctl command conventions. 1100 * 1101 * Returns 0 if allowed, error code otherwise 1102 */ 1103 static int smack_file_ioctl(struct file *file, unsigned int cmd, 1104 unsigned long arg) 1105 { 1106 int rc = 0; 1107 struct smk_audit_info ad; 1108 1109 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); 1110 smk_ad_setfield_u_fs_path(&ad, file->f_path); 1111 1112 if (_IOC_DIR(cmd) & _IOC_WRITE) 1113 rc = smk_curacc(file->f_security, MAY_WRITE, &ad); 1114 1115 if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ)) 1116 rc = smk_curacc(file->f_security, MAY_READ, &ad); 1117 1118 return rc; 1119 } 1120 1121 /** 1122 * smack_file_lock - Smack check on file locking 1123 * @file: the object 1124 * @cmd: unused 1125 * 1126 * Returns 0 if current has write access, error code otherwise 1127 */ 1128 static int smack_file_lock(struct file *file, unsigned int cmd) 1129 { 1130 struct smk_audit_info ad; 1131 1132 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); 1133 smk_ad_setfield_u_fs_path(&ad, file->f_path); 1134 return smk_curacc(file->f_security, MAY_WRITE, &ad); 1135 } 1136 1137 /** 1138 * smack_file_fcntl - Smack check on fcntl 1139 * @file: the object 1140 * @cmd: what action to check 1141 * @arg: unused 1142 * 1143 * Generally these operations are harmless. 1144 * File locking operations present an obvious mechanism 1145 * for passing information, so they require write access. 1146 * 1147 * Returns 0 if current has access, error code otherwise 1148 */ 1149 static int smack_file_fcntl(struct file *file, unsigned int cmd, 1150 unsigned long arg) 1151 { 1152 struct smk_audit_info ad; 1153 int rc = 0; 1154 1155 1156 switch (cmd) { 1157 case F_GETLK: 1158 case F_SETLK: 1159 case F_SETLKW: 1160 case F_SETOWN: 1161 case F_SETSIG: 1162 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); 1163 smk_ad_setfield_u_fs_path(&ad, file->f_path); 1164 rc = smk_curacc(file->f_security, MAY_WRITE, &ad); 1165 break; 1166 default: 1167 break; 1168 } 1169 1170 return rc; 1171 } 1172 1173 /** 1174 * smack_file_mmap : 1175 * Check permissions for a mmap operation. The @file may be NULL, e.g. 1176 * if mapping anonymous memory. 1177 * @file contains the file structure for file to map (may be NULL). 1178 * @reqprot contains the protection requested by the application. 1179 * @prot contains the protection that will be applied by the kernel. 1180 * @flags contains the operational flags. 1181 * Return 0 if permission is granted. 1182 */ 1183 static int smack_file_mmap(struct file *file, 1184 unsigned long reqprot, unsigned long prot, 1185 unsigned long flags, unsigned long addr, 1186 unsigned long addr_only) 1187 { 1188 struct smack_known *skp; 1189 struct smack_rule *srp; 1190 struct task_smack *tsp; 1191 char *sp; 1192 char *msmack; 1193 char *osmack; 1194 struct inode_smack *isp; 1195 struct dentry *dp; 1196 int may; 1197 int mmay; 1198 int tmay; 1199 int rc; 1200 1201 /* do DAC check on address space usage */ 1202 rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only); 1203 if (rc || addr_only) 1204 return rc; 1205 1206 if (file == NULL || file->f_dentry == NULL) 1207 return 0; 1208 1209 dp = file->f_dentry; 1210 1211 if (dp->d_inode == NULL) 1212 return 0; 1213 1214 isp = dp->d_inode->i_security; 1215 if (isp->smk_mmap == NULL) 1216 return 0; 1217 msmack = isp->smk_mmap; 1218 1219 tsp = current_security(); 1220 sp = smk_of_current(); 1221 skp = smk_find_entry(sp); 1222 rc = 0; 1223 1224 rcu_read_lock(); 1225 /* 1226 * For each Smack rule associated with the subject 1227 * label verify that the SMACK64MMAP also has access 1228 * to that rule's object label. 1229 */ 1230 list_for_each_entry_rcu(srp, &skp->smk_rules, list) { 1231 osmack = srp->smk_object; 1232 /* 1233 * Matching labels always allows access. 1234 */ 1235 if (msmack == osmack) 1236 continue; 1237 /* 1238 * If there is a matching local rule take 1239 * that into account as well. 1240 */ 1241 may = smk_access_entry(srp->smk_subject, osmack, 1242 &tsp->smk_rules); 1243 if (may == -ENOENT) 1244 may = srp->smk_access; 1245 else 1246 may &= srp->smk_access; 1247 /* 1248 * If may is zero the SMACK64MMAP subject can't 1249 * possibly have less access. 1250 */ 1251 if (may == 0) 1252 continue; 1253 1254 /* 1255 * Fetch the global list entry. 1256 * If there isn't one a SMACK64MMAP subject 1257 * can't have as much access as current. 1258 */ 1259 skp = smk_find_entry(msmack); 1260 mmay = smk_access_entry(msmack, osmack, &skp->smk_rules); 1261 if (mmay == -ENOENT) { 1262 rc = -EACCES; 1263 break; 1264 } 1265 /* 1266 * If there is a local entry it modifies the 1267 * potential access, too. 1268 */ 1269 tmay = smk_access_entry(msmack, osmack, &tsp->smk_rules); 1270 if (tmay != -ENOENT) 1271 mmay &= tmay; 1272 1273 /* 1274 * If there is any access available to current that is 1275 * not available to a SMACK64MMAP subject 1276 * deny access. 1277 */ 1278 if ((may | mmay) != mmay) { 1279 rc = -EACCES; 1280 break; 1281 } 1282 } 1283 1284 rcu_read_unlock(); 1285 1286 return rc; 1287 } 1288 1289 /** 1290 * smack_file_set_fowner - set the file security blob value 1291 * @file: object in question 1292 * 1293 * Returns 0 1294 * Further research may be required on this one. 1295 */ 1296 static int smack_file_set_fowner(struct file *file) 1297 { 1298 file->f_security = smk_of_current(); 1299 return 0; 1300 } 1301 1302 /** 1303 * smack_file_send_sigiotask - Smack on sigio 1304 * @tsk: The target task 1305 * @fown: the object the signal come from 1306 * @signum: unused 1307 * 1308 * Allow a privileged task to get signals even if it shouldn't 1309 * 1310 * Returns 0 if a subject with the object's smack could 1311 * write to the task, an error code otherwise. 1312 */ 1313 static int smack_file_send_sigiotask(struct task_struct *tsk, 1314 struct fown_struct *fown, int signum) 1315 { 1316 struct file *file; 1317 int rc; 1318 char *tsp = smk_of_task(tsk->cred->security); 1319 struct smk_audit_info ad; 1320 1321 /* 1322 * struct fown_struct is never outside the context of a struct file 1323 */ 1324 file = container_of(fown, struct file, f_owner); 1325 1326 /* we don't log here as rc can be overriden */ 1327 rc = smk_access(file->f_security, tsp, MAY_WRITE, NULL); 1328 if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE)) 1329 rc = 0; 1330 1331 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); 1332 smk_ad_setfield_u_tsk(&ad, tsk); 1333 smack_log(file->f_security, tsp, MAY_WRITE, rc, &ad); 1334 return rc; 1335 } 1336 1337 /** 1338 * smack_file_receive - Smack file receive check 1339 * @file: the object 1340 * 1341 * Returns 0 if current has access, error code otherwise 1342 */ 1343 static int smack_file_receive(struct file *file) 1344 { 1345 int may = 0; 1346 struct smk_audit_info ad; 1347 1348 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); 1349 smk_ad_setfield_u_fs_path(&ad, file->f_path); 1350 /* 1351 * This code relies on bitmasks. 1352 */ 1353 if (file->f_mode & FMODE_READ) 1354 may = MAY_READ; 1355 if (file->f_mode & FMODE_WRITE) 1356 may |= MAY_WRITE; 1357 1358 return smk_curacc(file->f_security, may, &ad); 1359 } 1360 1361 /** 1362 * smack_file_open - Smack dentry open processing 1363 * @file: the object 1364 * @cred: unused 1365 * 1366 * Set the security blob in the file structure. 1367 * 1368 * Returns 0 1369 */ 1370 static int smack_file_open(struct file *file, const struct cred *cred) 1371 { 1372 struct inode_smack *isp = file->f_path.dentry->d_inode->i_security; 1373 1374 file->f_security = isp->smk_inode; 1375 1376 return 0; 1377 } 1378 1379 /* 1380 * Task hooks 1381 */ 1382 1383 /** 1384 * smack_cred_alloc_blank - "allocate" blank task-level security credentials 1385 * @new: the new credentials 1386 * @gfp: the atomicity of any memory allocations 1387 * 1388 * Prepare a blank set of credentials for modification. This must allocate all 1389 * the memory the LSM module might require such that cred_transfer() can 1390 * complete without error. 1391 */ 1392 static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp) 1393 { 1394 struct task_smack *tsp; 1395 1396 tsp = new_task_smack(NULL, NULL, gfp); 1397 if (tsp == NULL) 1398 return -ENOMEM; 1399 1400 cred->security = tsp; 1401 1402 return 0; 1403 } 1404 1405 1406 /** 1407 * smack_cred_free - "free" task-level security credentials 1408 * @cred: the credentials in question 1409 * 1410 */ 1411 static void smack_cred_free(struct cred *cred) 1412 { 1413 struct task_smack *tsp = cred->security; 1414 struct smack_rule *rp; 1415 struct list_head *l; 1416 struct list_head *n; 1417 1418 if (tsp == NULL) 1419 return; 1420 cred->security = NULL; 1421 1422 list_for_each_safe(l, n, &tsp->smk_rules) { 1423 rp = list_entry(l, struct smack_rule, list); 1424 list_del(&rp->list); 1425 kfree(rp); 1426 } 1427 kfree(tsp); 1428 } 1429 1430 /** 1431 * smack_cred_prepare - prepare new set of credentials for modification 1432 * @new: the new credentials 1433 * @old: the original credentials 1434 * @gfp: the atomicity of any memory allocations 1435 * 1436 * Prepare a new set of credentials for modification. 1437 */ 1438 static int smack_cred_prepare(struct cred *new, const struct cred *old, 1439 gfp_t gfp) 1440 { 1441 struct task_smack *old_tsp = old->security; 1442 struct task_smack *new_tsp; 1443 int rc; 1444 1445 new_tsp = new_task_smack(old_tsp->smk_task, old_tsp->smk_task, gfp); 1446 if (new_tsp == NULL) 1447 return -ENOMEM; 1448 1449 rc = smk_copy_rules(&new_tsp->smk_rules, &old_tsp->smk_rules, gfp); 1450 if (rc != 0) 1451 return rc; 1452 1453 new->security = new_tsp; 1454 return 0; 1455 } 1456 1457 /** 1458 * smack_cred_transfer - Transfer the old credentials to the new credentials 1459 * @new: the new credentials 1460 * @old: the original credentials 1461 * 1462 * Fill in a set of blank credentials from another set of credentials. 1463 */ 1464 static void smack_cred_transfer(struct cred *new, const struct cred *old) 1465 { 1466 struct task_smack *old_tsp = old->security; 1467 struct task_smack *new_tsp = new->security; 1468 1469 new_tsp->smk_task = old_tsp->smk_task; 1470 new_tsp->smk_forked = old_tsp->smk_task; 1471 mutex_init(&new_tsp->smk_rules_lock); 1472 INIT_LIST_HEAD(&new_tsp->smk_rules); 1473 1474 1475 /* cbs copy rule list */ 1476 } 1477 1478 /** 1479 * smack_kernel_act_as - Set the subjective context in a set of credentials 1480 * @new: points to the set of credentials to be modified. 1481 * @secid: specifies the security ID to be set 1482 * 1483 * Set the security data for a kernel service. 1484 */ 1485 static int smack_kernel_act_as(struct cred *new, u32 secid) 1486 { 1487 struct task_smack *new_tsp = new->security; 1488 char *smack = smack_from_secid(secid); 1489 1490 if (smack == NULL) 1491 return -EINVAL; 1492 1493 new_tsp->smk_task = smack; 1494 return 0; 1495 } 1496 1497 /** 1498 * smack_kernel_create_files_as - Set the file creation label in a set of creds 1499 * @new: points to the set of credentials to be modified 1500 * @inode: points to the inode to use as a reference 1501 * 1502 * Set the file creation context in a set of credentials to the same 1503 * as the objective context of the specified inode 1504 */ 1505 static int smack_kernel_create_files_as(struct cred *new, 1506 struct inode *inode) 1507 { 1508 struct inode_smack *isp = inode->i_security; 1509 struct task_smack *tsp = new->security; 1510 1511 tsp->smk_forked = isp->smk_inode; 1512 tsp->smk_task = isp->smk_inode; 1513 return 0; 1514 } 1515 1516 /** 1517 * smk_curacc_on_task - helper to log task related access 1518 * @p: the task object 1519 * @access: the access requested 1520 * @caller: name of the calling function for audit 1521 * 1522 * Return 0 if access is permitted 1523 */ 1524 static int smk_curacc_on_task(struct task_struct *p, int access, 1525 const char *caller) 1526 { 1527 struct smk_audit_info ad; 1528 1529 smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK); 1530 smk_ad_setfield_u_tsk(&ad, p); 1531 return smk_curacc(smk_of_task(task_security(p)), access, &ad); 1532 } 1533 1534 /** 1535 * smack_task_setpgid - Smack check on setting pgid 1536 * @p: the task object 1537 * @pgid: unused 1538 * 1539 * Return 0 if write access is permitted 1540 */ 1541 static int smack_task_setpgid(struct task_struct *p, pid_t pgid) 1542 { 1543 return smk_curacc_on_task(p, MAY_WRITE, __func__); 1544 } 1545 1546 /** 1547 * smack_task_getpgid - Smack access check for getpgid 1548 * @p: the object task 1549 * 1550 * Returns 0 if current can read the object task, error code otherwise 1551 */ 1552 static int smack_task_getpgid(struct task_struct *p) 1553 { 1554 return smk_curacc_on_task(p, MAY_READ, __func__); 1555 } 1556 1557 /** 1558 * smack_task_getsid - Smack access check for getsid 1559 * @p: the object task 1560 * 1561 * Returns 0 if current can read the object task, error code otherwise 1562 */ 1563 static int smack_task_getsid(struct task_struct *p) 1564 { 1565 return smk_curacc_on_task(p, MAY_READ, __func__); 1566 } 1567 1568 /** 1569 * smack_task_getsecid - get the secid of the task 1570 * @p: the object task 1571 * @secid: where to put the result 1572 * 1573 * Sets the secid to contain a u32 version of the smack label. 1574 */ 1575 static void smack_task_getsecid(struct task_struct *p, u32 *secid) 1576 { 1577 *secid = smack_to_secid(smk_of_task(task_security(p))); 1578 } 1579 1580 /** 1581 * smack_task_setnice - Smack check on setting nice 1582 * @p: the task object 1583 * @nice: unused 1584 * 1585 * Return 0 if write access is permitted 1586 */ 1587 static int smack_task_setnice(struct task_struct *p, int nice) 1588 { 1589 int rc; 1590 1591 rc = cap_task_setnice(p, nice); 1592 if (rc == 0) 1593 rc = smk_curacc_on_task(p, MAY_WRITE, __func__); 1594 return rc; 1595 } 1596 1597 /** 1598 * smack_task_setioprio - Smack check on setting ioprio 1599 * @p: the task object 1600 * @ioprio: unused 1601 * 1602 * Return 0 if write access is permitted 1603 */ 1604 static int smack_task_setioprio(struct task_struct *p, int ioprio) 1605 { 1606 int rc; 1607 1608 rc = cap_task_setioprio(p, ioprio); 1609 if (rc == 0) 1610 rc = smk_curacc_on_task(p, MAY_WRITE, __func__); 1611 return rc; 1612 } 1613 1614 /** 1615 * smack_task_getioprio - Smack check on reading ioprio 1616 * @p: the task object 1617 * 1618 * Return 0 if read access is permitted 1619 */ 1620 static int smack_task_getioprio(struct task_struct *p) 1621 { 1622 return smk_curacc_on_task(p, MAY_READ, __func__); 1623 } 1624 1625 /** 1626 * smack_task_setscheduler - Smack check on setting scheduler 1627 * @p: the task object 1628 * @policy: unused 1629 * @lp: unused 1630 * 1631 * Return 0 if read access is permitted 1632 */ 1633 static int smack_task_setscheduler(struct task_struct *p) 1634 { 1635 int rc; 1636 1637 rc = cap_task_setscheduler(p); 1638 if (rc == 0) 1639 rc = smk_curacc_on_task(p, MAY_WRITE, __func__); 1640 return rc; 1641 } 1642 1643 /** 1644 * smack_task_getscheduler - Smack check on reading scheduler 1645 * @p: the task object 1646 * 1647 * Return 0 if read access is permitted 1648 */ 1649 static int smack_task_getscheduler(struct task_struct *p) 1650 { 1651 return smk_curacc_on_task(p, MAY_READ, __func__); 1652 } 1653 1654 /** 1655 * smack_task_movememory - Smack check on moving memory 1656 * @p: the task object 1657 * 1658 * Return 0 if write access is permitted 1659 */ 1660 static int smack_task_movememory(struct task_struct *p) 1661 { 1662 return smk_curacc_on_task(p, MAY_WRITE, __func__); 1663 } 1664 1665 /** 1666 * smack_task_kill - Smack check on signal delivery 1667 * @p: the task object 1668 * @info: unused 1669 * @sig: unused 1670 * @secid: identifies the smack to use in lieu of current's 1671 * 1672 * Return 0 if write access is permitted 1673 * 1674 * The secid behavior is an artifact of an SELinux hack 1675 * in the USB code. Someday it may go away. 1676 */ 1677 static int smack_task_kill(struct task_struct *p, struct siginfo *info, 1678 int sig, u32 secid) 1679 { 1680 struct smk_audit_info ad; 1681 1682 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); 1683 smk_ad_setfield_u_tsk(&ad, p); 1684 /* 1685 * Sending a signal requires that the sender 1686 * can write the receiver. 1687 */ 1688 if (secid == 0) 1689 return smk_curacc(smk_of_task(task_security(p)), MAY_WRITE, 1690 &ad); 1691 /* 1692 * If the secid isn't 0 we're dealing with some USB IO 1693 * specific behavior. This is not clean. For one thing 1694 * we can't take privilege into account. 1695 */ 1696 return smk_access(smack_from_secid(secid), 1697 smk_of_task(task_security(p)), MAY_WRITE, &ad); 1698 } 1699 1700 /** 1701 * smack_task_wait - Smack access check for waiting 1702 * @p: task to wait for 1703 * 1704 * Returns 0 if current can wait for p, error code otherwise 1705 */ 1706 static int smack_task_wait(struct task_struct *p) 1707 { 1708 struct smk_audit_info ad; 1709 char *sp = smk_of_current(); 1710 char *tsp = smk_of_forked(task_security(p)); 1711 int rc; 1712 1713 /* we don't log here, we can be overriden */ 1714 rc = smk_access(tsp, sp, MAY_WRITE, NULL); 1715 if (rc == 0) 1716 goto out_log; 1717 1718 /* 1719 * Allow the operation to succeed if either task 1720 * has privilege to perform operations that might 1721 * account for the smack labels having gotten to 1722 * be different in the first place. 1723 * 1724 * This breaks the strict subject/object access 1725 * control ideal, taking the object's privilege 1726 * state into account in the decision as well as 1727 * the smack value. 1728 */ 1729 if (capable(CAP_MAC_OVERRIDE) || has_capability(p, CAP_MAC_OVERRIDE)) 1730 rc = 0; 1731 /* we log only if we didn't get overriden */ 1732 out_log: 1733 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); 1734 smk_ad_setfield_u_tsk(&ad, p); 1735 smack_log(tsp, sp, MAY_WRITE, rc, &ad); 1736 return rc; 1737 } 1738 1739 /** 1740 * smack_task_to_inode - copy task smack into the inode blob 1741 * @p: task to copy from 1742 * @inode: inode to copy to 1743 * 1744 * Sets the smack pointer in the inode security blob 1745 */ 1746 static void smack_task_to_inode(struct task_struct *p, struct inode *inode) 1747 { 1748 struct inode_smack *isp = inode->i_security; 1749 isp->smk_inode = smk_of_task(task_security(p)); 1750 } 1751 1752 /* 1753 * Socket hooks. 1754 */ 1755 1756 /** 1757 * smack_sk_alloc_security - Allocate a socket blob 1758 * @sk: the socket 1759 * @family: unused 1760 * @gfp_flags: memory allocation flags 1761 * 1762 * Assign Smack pointers to current 1763 * 1764 * Returns 0 on success, -ENOMEM is there's no memory 1765 */ 1766 static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags) 1767 { 1768 char *csp = smk_of_current(); 1769 struct socket_smack *ssp; 1770 1771 ssp = kzalloc(sizeof(struct socket_smack), gfp_flags); 1772 if (ssp == NULL) 1773 return -ENOMEM; 1774 1775 ssp->smk_in = csp; 1776 ssp->smk_out = csp; 1777 ssp->smk_packet = NULL; 1778 1779 sk->sk_security = ssp; 1780 1781 return 0; 1782 } 1783 1784 /** 1785 * smack_sk_free_security - Free a socket blob 1786 * @sk: the socket 1787 * 1788 * Clears the blob pointer 1789 */ 1790 static void smack_sk_free_security(struct sock *sk) 1791 { 1792 kfree(sk->sk_security); 1793 } 1794 1795 /** 1796 * smack_host_label - check host based restrictions 1797 * @sip: the object end 1798 * 1799 * looks for host based access restrictions 1800 * 1801 * This version will only be appropriate for really small sets of single label 1802 * hosts. The caller is responsible for ensuring that the RCU read lock is 1803 * taken before calling this function. 1804 * 1805 * Returns the label of the far end or NULL if it's not special. 1806 */ 1807 static char *smack_host_label(struct sockaddr_in *sip) 1808 { 1809 struct smk_netlbladdr *snp; 1810 struct in_addr *siap = &sip->sin_addr; 1811 1812 if (siap->s_addr == 0) 1813 return NULL; 1814 1815 list_for_each_entry_rcu(snp, &smk_netlbladdr_list, list) 1816 /* 1817 * we break after finding the first match because 1818 * the list is sorted from longest to shortest mask 1819 * so we have found the most specific match 1820 */ 1821 if ((&snp->smk_host.sin_addr)->s_addr == 1822 (siap->s_addr & (&snp->smk_mask)->s_addr)) { 1823 /* we have found the special CIPSO option */ 1824 if (snp->smk_label == smack_cipso_option) 1825 return NULL; 1826 return snp->smk_label; 1827 } 1828 1829 return NULL; 1830 } 1831 1832 /** 1833 * smack_netlabel - Set the secattr on a socket 1834 * @sk: the socket 1835 * @labeled: socket label scheme 1836 * 1837 * Convert the outbound smack value (smk_out) to a 1838 * secattr and attach it to the socket. 1839 * 1840 * Returns 0 on success or an error code 1841 */ 1842 static int smack_netlabel(struct sock *sk, int labeled) 1843 { 1844 struct smack_known *skp; 1845 struct socket_smack *ssp = sk->sk_security; 1846 int rc = 0; 1847 1848 /* 1849 * Usually the netlabel code will handle changing the 1850 * packet labeling based on the label. 1851 * The case of a single label host is different, because 1852 * a single label host should never get a labeled packet 1853 * even though the label is usually associated with a packet 1854 * label. 1855 */ 1856 local_bh_disable(); 1857 bh_lock_sock_nested(sk); 1858 1859 if (ssp->smk_out == smack_net_ambient || 1860 labeled == SMACK_UNLABELED_SOCKET) 1861 netlbl_sock_delattr(sk); 1862 else { 1863 skp = smk_find_entry(ssp->smk_out); 1864 rc = netlbl_sock_setattr(sk, sk->sk_family, &skp->smk_netlabel); 1865 } 1866 1867 bh_unlock_sock(sk); 1868 local_bh_enable(); 1869 1870 return rc; 1871 } 1872 1873 /** 1874 * smack_netlbel_send - Set the secattr on a socket and perform access checks 1875 * @sk: the socket 1876 * @sap: the destination address 1877 * 1878 * Set the correct secattr for the given socket based on the destination 1879 * address and perform any outbound access checks needed. 1880 * 1881 * Returns 0 on success or an error code. 1882 * 1883 */ 1884 static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap) 1885 { 1886 int rc; 1887 int sk_lbl; 1888 char *hostsp; 1889 struct socket_smack *ssp = sk->sk_security; 1890 struct smk_audit_info ad; 1891 1892 rcu_read_lock(); 1893 hostsp = smack_host_label(sap); 1894 if (hostsp != NULL) { 1895 #ifdef CONFIG_AUDIT 1896 struct lsm_network_audit net; 1897 1898 smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); 1899 ad.a.u.net->family = sap->sin_family; 1900 ad.a.u.net->dport = sap->sin_port; 1901 ad.a.u.net->v4info.daddr = sap->sin_addr.s_addr; 1902 #endif 1903 sk_lbl = SMACK_UNLABELED_SOCKET; 1904 rc = smk_access(ssp->smk_out, hostsp, MAY_WRITE, &ad); 1905 } else { 1906 sk_lbl = SMACK_CIPSO_SOCKET; 1907 rc = 0; 1908 } 1909 rcu_read_unlock(); 1910 if (rc != 0) 1911 return rc; 1912 1913 return smack_netlabel(sk, sk_lbl); 1914 } 1915 1916 /** 1917 * smack_inode_setsecurity - set smack xattrs 1918 * @inode: the object 1919 * @name: attribute name 1920 * @value: attribute value 1921 * @size: size of the attribute 1922 * @flags: unused 1923 * 1924 * Sets the named attribute in the appropriate blob 1925 * 1926 * Returns 0 on success, or an error code 1927 */ 1928 static int smack_inode_setsecurity(struct inode *inode, const char *name, 1929 const void *value, size_t size, int flags) 1930 { 1931 char *sp; 1932 struct inode_smack *nsp = inode->i_security; 1933 struct socket_smack *ssp; 1934 struct socket *sock; 1935 int rc = 0; 1936 1937 if (value == NULL || size > SMK_LONGLABEL || size == 0) 1938 return -EACCES; 1939 1940 sp = smk_import(value, size); 1941 if (sp == NULL) 1942 return -EINVAL; 1943 1944 if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) { 1945 nsp->smk_inode = sp; 1946 nsp->smk_flags |= SMK_INODE_INSTANT; 1947 return 0; 1948 } 1949 /* 1950 * The rest of the Smack xattrs are only on sockets. 1951 */ 1952 if (inode->i_sb->s_magic != SOCKFS_MAGIC) 1953 return -EOPNOTSUPP; 1954 1955 sock = SOCKET_I(inode); 1956 if (sock == NULL || sock->sk == NULL) 1957 return -EOPNOTSUPP; 1958 1959 ssp = sock->sk->sk_security; 1960 1961 if (strcmp(name, XATTR_SMACK_IPIN) == 0) 1962 ssp->smk_in = sp; 1963 else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) { 1964 ssp->smk_out = sp; 1965 if (sock->sk->sk_family != PF_UNIX) { 1966 rc = smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET); 1967 if (rc != 0) 1968 printk(KERN_WARNING 1969 "Smack: \"%s\" netlbl error %d.\n", 1970 __func__, -rc); 1971 } 1972 } else 1973 return -EOPNOTSUPP; 1974 1975 return 0; 1976 } 1977 1978 /** 1979 * smack_socket_post_create - finish socket setup 1980 * @sock: the socket 1981 * @family: protocol family 1982 * @type: unused 1983 * @protocol: unused 1984 * @kern: unused 1985 * 1986 * Sets the netlabel information on the socket 1987 * 1988 * Returns 0 on success, and error code otherwise 1989 */ 1990 static int smack_socket_post_create(struct socket *sock, int family, 1991 int type, int protocol, int kern) 1992 { 1993 if (family != PF_INET || sock->sk == NULL) 1994 return 0; 1995 /* 1996 * Set the outbound netlbl. 1997 */ 1998 return smack_netlabel(sock->sk, SMACK_CIPSO_SOCKET); 1999 } 2000 2001 /** 2002 * smack_socket_connect - connect access check 2003 * @sock: the socket 2004 * @sap: the other end 2005 * @addrlen: size of sap 2006 * 2007 * Verifies that a connection may be possible 2008 * 2009 * Returns 0 on success, and error code otherwise 2010 */ 2011 static int smack_socket_connect(struct socket *sock, struct sockaddr *sap, 2012 int addrlen) 2013 { 2014 if (sock->sk == NULL || sock->sk->sk_family != PF_INET) 2015 return 0; 2016 if (addrlen < sizeof(struct sockaddr_in)) 2017 return -EINVAL; 2018 2019 return smack_netlabel_send(sock->sk, (struct sockaddr_in *)sap); 2020 } 2021 2022 /** 2023 * smack_flags_to_may - convert S_ to MAY_ values 2024 * @flags: the S_ value 2025 * 2026 * Returns the equivalent MAY_ value 2027 */ 2028 static int smack_flags_to_may(int flags) 2029 { 2030 int may = 0; 2031 2032 if (flags & S_IRUGO) 2033 may |= MAY_READ; 2034 if (flags & S_IWUGO) 2035 may |= MAY_WRITE; 2036 if (flags & S_IXUGO) 2037 may |= MAY_EXEC; 2038 2039 return may; 2040 } 2041 2042 /** 2043 * smack_msg_msg_alloc_security - Set the security blob for msg_msg 2044 * @msg: the object 2045 * 2046 * Returns 0 2047 */ 2048 static int smack_msg_msg_alloc_security(struct msg_msg *msg) 2049 { 2050 msg->security = smk_of_current(); 2051 return 0; 2052 } 2053 2054 /** 2055 * smack_msg_msg_free_security - Clear the security blob for msg_msg 2056 * @msg: the object 2057 * 2058 * Clears the blob pointer 2059 */ 2060 static void smack_msg_msg_free_security(struct msg_msg *msg) 2061 { 2062 msg->security = NULL; 2063 } 2064 2065 /** 2066 * smack_of_shm - the smack pointer for the shm 2067 * @shp: the object 2068 * 2069 * Returns a pointer to the smack value 2070 */ 2071 static char *smack_of_shm(struct shmid_kernel *shp) 2072 { 2073 return (char *)shp->shm_perm.security; 2074 } 2075 2076 /** 2077 * smack_shm_alloc_security - Set the security blob for shm 2078 * @shp: the object 2079 * 2080 * Returns 0 2081 */ 2082 static int smack_shm_alloc_security(struct shmid_kernel *shp) 2083 { 2084 struct kern_ipc_perm *isp = &shp->shm_perm; 2085 2086 isp->security = smk_of_current(); 2087 return 0; 2088 } 2089 2090 /** 2091 * smack_shm_free_security - Clear the security blob for shm 2092 * @shp: the object 2093 * 2094 * Clears the blob pointer 2095 */ 2096 static void smack_shm_free_security(struct shmid_kernel *shp) 2097 { 2098 struct kern_ipc_perm *isp = &shp->shm_perm; 2099 2100 isp->security = NULL; 2101 } 2102 2103 /** 2104 * smk_curacc_shm : check if current has access on shm 2105 * @shp : the object 2106 * @access : access requested 2107 * 2108 * Returns 0 if current has the requested access, error code otherwise 2109 */ 2110 static int smk_curacc_shm(struct shmid_kernel *shp, int access) 2111 { 2112 char *ssp = smack_of_shm(shp); 2113 struct smk_audit_info ad; 2114 2115 #ifdef CONFIG_AUDIT 2116 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC); 2117 ad.a.u.ipc_id = shp->shm_perm.id; 2118 #endif 2119 return smk_curacc(ssp, access, &ad); 2120 } 2121 2122 /** 2123 * smack_shm_associate - Smack access check for shm 2124 * @shp: the object 2125 * @shmflg: access requested 2126 * 2127 * Returns 0 if current has the requested access, error code otherwise 2128 */ 2129 static int smack_shm_associate(struct shmid_kernel *shp, int shmflg) 2130 { 2131 int may; 2132 2133 may = smack_flags_to_may(shmflg); 2134 return smk_curacc_shm(shp, may); 2135 } 2136 2137 /** 2138 * smack_shm_shmctl - Smack access check for shm 2139 * @shp: the object 2140 * @cmd: what it wants to do 2141 * 2142 * Returns 0 if current has the requested access, error code otherwise 2143 */ 2144 static int smack_shm_shmctl(struct shmid_kernel *shp, int cmd) 2145 { 2146 int may; 2147 2148 switch (cmd) { 2149 case IPC_STAT: 2150 case SHM_STAT: 2151 may = MAY_READ; 2152 break; 2153 case IPC_SET: 2154 case SHM_LOCK: 2155 case SHM_UNLOCK: 2156 case IPC_RMID: 2157 may = MAY_READWRITE; 2158 break; 2159 case IPC_INFO: 2160 case SHM_INFO: 2161 /* 2162 * System level information. 2163 */ 2164 return 0; 2165 default: 2166 return -EINVAL; 2167 } 2168 return smk_curacc_shm(shp, may); 2169 } 2170 2171 /** 2172 * smack_shm_shmat - Smack access for shmat 2173 * @shp: the object 2174 * @shmaddr: unused 2175 * @shmflg: access requested 2176 * 2177 * Returns 0 if current has the requested access, error code otherwise 2178 */ 2179 static int smack_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr, 2180 int shmflg) 2181 { 2182 int may; 2183 2184 may = smack_flags_to_may(shmflg); 2185 return smk_curacc_shm(shp, may); 2186 } 2187 2188 /** 2189 * smack_of_sem - the smack pointer for the sem 2190 * @sma: the object 2191 * 2192 * Returns a pointer to the smack value 2193 */ 2194 static char *smack_of_sem(struct sem_array *sma) 2195 { 2196 return (char *)sma->sem_perm.security; 2197 } 2198 2199 /** 2200 * smack_sem_alloc_security - Set the security blob for sem 2201 * @sma: the object 2202 * 2203 * Returns 0 2204 */ 2205 static int smack_sem_alloc_security(struct sem_array *sma) 2206 { 2207 struct kern_ipc_perm *isp = &sma->sem_perm; 2208 2209 isp->security = smk_of_current(); 2210 return 0; 2211 } 2212 2213 /** 2214 * smack_sem_free_security - Clear the security blob for sem 2215 * @sma: the object 2216 * 2217 * Clears the blob pointer 2218 */ 2219 static void smack_sem_free_security(struct sem_array *sma) 2220 { 2221 struct kern_ipc_perm *isp = &sma->sem_perm; 2222 2223 isp->security = NULL; 2224 } 2225 2226 /** 2227 * smk_curacc_sem : check if current has access on sem 2228 * @sma : the object 2229 * @access : access requested 2230 * 2231 * Returns 0 if current has the requested access, error code otherwise 2232 */ 2233 static int smk_curacc_sem(struct sem_array *sma, int access) 2234 { 2235 char *ssp = smack_of_sem(sma); 2236 struct smk_audit_info ad; 2237 2238 #ifdef CONFIG_AUDIT 2239 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC); 2240 ad.a.u.ipc_id = sma->sem_perm.id; 2241 #endif 2242 return smk_curacc(ssp, access, &ad); 2243 } 2244 2245 /** 2246 * smack_sem_associate - Smack access check for sem 2247 * @sma: the object 2248 * @semflg: access requested 2249 * 2250 * Returns 0 if current has the requested access, error code otherwise 2251 */ 2252 static int smack_sem_associate(struct sem_array *sma, int semflg) 2253 { 2254 int may; 2255 2256 may = smack_flags_to_may(semflg); 2257 return smk_curacc_sem(sma, may); 2258 } 2259 2260 /** 2261 * smack_sem_shmctl - Smack access check for sem 2262 * @sma: the object 2263 * @cmd: what it wants to do 2264 * 2265 * Returns 0 if current has the requested access, error code otherwise 2266 */ 2267 static int smack_sem_semctl(struct sem_array *sma, int cmd) 2268 { 2269 int may; 2270 2271 switch (cmd) { 2272 case GETPID: 2273 case GETNCNT: 2274 case GETZCNT: 2275 case GETVAL: 2276 case GETALL: 2277 case IPC_STAT: 2278 case SEM_STAT: 2279 may = MAY_READ; 2280 break; 2281 case SETVAL: 2282 case SETALL: 2283 case IPC_RMID: 2284 case IPC_SET: 2285 may = MAY_READWRITE; 2286 break; 2287 case IPC_INFO: 2288 case SEM_INFO: 2289 /* 2290 * System level information 2291 */ 2292 return 0; 2293 default: 2294 return -EINVAL; 2295 } 2296 2297 return smk_curacc_sem(sma, may); 2298 } 2299 2300 /** 2301 * smack_sem_semop - Smack checks of semaphore operations 2302 * @sma: the object 2303 * @sops: unused 2304 * @nsops: unused 2305 * @alter: unused 2306 * 2307 * Treated as read and write in all cases. 2308 * 2309 * Returns 0 if access is allowed, error code otherwise 2310 */ 2311 static int smack_sem_semop(struct sem_array *sma, struct sembuf *sops, 2312 unsigned nsops, int alter) 2313 { 2314 return smk_curacc_sem(sma, MAY_READWRITE); 2315 } 2316 2317 /** 2318 * smack_msg_alloc_security - Set the security blob for msg 2319 * @msq: the object 2320 * 2321 * Returns 0 2322 */ 2323 static int smack_msg_queue_alloc_security(struct msg_queue *msq) 2324 { 2325 struct kern_ipc_perm *kisp = &msq->q_perm; 2326 2327 kisp->security = smk_of_current(); 2328 return 0; 2329 } 2330 2331 /** 2332 * smack_msg_free_security - Clear the security blob for msg 2333 * @msq: the object 2334 * 2335 * Clears the blob pointer 2336 */ 2337 static void smack_msg_queue_free_security(struct msg_queue *msq) 2338 { 2339 struct kern_ipc_perm *kisp = &msq->q_perm; 2340 2341 kisp->security = NULL; 2342 } 2343 2344 /** 2345 * smack_of_msq - the smack pointer for the msq 2346 * @msq: the object 2347 * 2348 * Returns a pointer to the smack value 2349 */ 2350 static char *smack_of_msq(struct msg_queue *msq) 2351 { 2352 return (char *)msq->q_perm.security; 2353 } 2354 2355 /** 2356 * smk_curacc_msq : helper to check if current has access on msq 2357 * @msq : the msq 2358 * @access : access requested 2359 * 2360 * return 0 if current has access, error otherwise 2361 */ 2362 static int smk_curacc_msq(struct msg_queue *msq, int access) 2363 { 2364 char *msp = smack_of_msq(msq); 2365 struct smk_audit_info ad; 2366 2367 #ifdef CONFIG_AUDIT 2368 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC); 2369 ad.a.u.ipc_id = msq->q_perm.id; 2370 #endif 2371 return smk_curacc(msp, access, &ad); 2372 } 2373 2374 /** 2375 * smack_msg_queue_associate - Smack access check for msg_queue 2376 * @msq: the object 2377 * @msqflg: access requested 2378 * 2379 * Returns 0 if current has the requested access, error code otherwise 2380 */ 2381 static int smack_msg_queue_associate(struct msg_queue *msq, int msqflg) 2382 { 2383 int may; 2384 2385 may = smack_flags_to_may(msqflg); 2386 return smk_curacc_msq(msq, may); 2387 } 2388 2389 /** 2390 * smack_msg_queue_msgctl - Smack access check for msg_queue 2391 * @msq: the object 2392 * @cmd: what it wants to do 2393 * 2394 * Returns 0 if current has the requested access, error code otherwise 2395 */ 2396 static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd) 2397 { 2398 int may; 2399 2400 switch (cmd) { 2401 case IPC_STAT: 2402 case MSG_STAT: 2403 may = MAY_READ; 2404 break; 2405 case IPC_SET: 2406 case IPC_RMID: 2407 may = MAY_READWRITE; 2408 break; 2409 case IPC_INFO: 2410 case MSG_INFO: 2411 /* 2412 * System level information 2413 */ 2414 return 0; 2415 default: 2416 return -EINVAL; 2417 } 2418 2419 return smk_curacc_msq(msq, may); 2420 } 2421 2422 /** 2423 * smack_msg_queue_msgsnd - Smack access check for msg_queue 2424 * @msq: the object 2425 * @msg: unused 2426 * @msqflg: access requested 2427 * 2428 * Returns 0 if current has the requested access, error code otherwise 2429 */ 2430 static int smack_msg_queue_msgsnd(struct msg_queue *msq, struct msg_msg *msg, 2431 int msqflg) 2432 { 2433 int may; 2434 2435 may = smack_flags_to_may(msqflg); 2436 return smk_curacc_msq(msq, may); 2437 } 2438 2439 /** 2440 * smack_msg_queue_msgsnd - Smack access check for msg_queue 2441 * @msq: the object 2442 * @msg: unused 2443 * @target: unused 2444 * @type: unused 2445 * @mode: unused 2446 * 2447 * Returns 0 if current has read and write access, error code otherwise 2448 */ 2449 static int smack_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg, 2450 struct task_struct *target, long type, int mode) 2451 { 2452 return smk_curacc_msq(msq, MAY_READWRITE); 2453 } 2454 2455 /** 2456 * smack_ipc_permission - Smack access for ipc_permission() 2457 * @ipp: the object permissions 2458 * @flag: access requested 2459 * 2460 * Returns 0 if current has read and write access, error code otherwise 2461 */ 2462 static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag) 2463 { 2464 char *isp = ipp->security; 2465 int may = smack_flags_to_may(flag); 2466 struct smk_audit_info ad; 2467 2468 #ifdef CONFIG_AUDIT 2469 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC); 2470 ad.a.u.ipc_id = ipp->id; 2471 #endif 2472 return smk_curacc(isp, may, &ad); 2473 } 2474 2475 /** 2476 * smack_ipc_getsecid - Extract smack security id 2477 * @ipp: the object permissions 2478 * @secid: where result will be saved 2479 */ 2480 static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid) 2481 { 2482 char *smack = ipp->security; 2483 2484 *secid = smack_to_secid(smack); 2485 } 2486 2487 /** 2488 * smack_d_instantiate - Make sure the blob is correct on an inode 2489 * @opt_dentry: dentry where inode will be attached 2490 * @inode: the object 2491 * 2492 * Set the inode's security blob if it hasn't been done already. 2493 */ 2494 static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) 2495 { 2496 struct super_block *sbp; 2497 struct superblock_smack *sbsp; 2498 struct inode_smack *isp; 2499 char *csp = smk_of_current(); 2500 char *fetched; 2501 char *final; 2502 char trattr[TRANS_TRUE_SIZE]; 2503 int transflag = 0; 2504 int rc; 2505 struct dentry *dp; 2506 2507 if (inode == NULL) 2508 return; 2509 2510 isp = inode->i_security; 2511 2512 mutex_lock(&isp->smk_lock); 2513 /* 2514 * If the inode is already instantiated 2515 * take the quick way out 2516 */ 2517 if (isp->smk_flags & SMK_INODE_INSTANT) 2518 goto unlockandout; 2519 2520 sbp = inode->i_sb; 2521 sbsp = sbp->s_security; 2522 /* 2523 * We're going to use the superblock default label 2524 * if there's no label on the file. 2525 */ 2526 final = sbsp->smk_default; 2527 2528 /* 2529 * If this is the root inode the superblock 2530 * may be in the process of initialization. 2531 * If that is the case use the root value out 2532 * of the superblock. 2533 */ 2534 if (opt_dentry->d_parent == opt_dentry) { 2535 isp->smk_inode = sbsp->smk_root; 2536 isp->smk_flags |= SMK_INODE_INSTANT; 2537 goto unlockandout; 2538 } 2539 2540 /* 2541 * This is pretty hackish. 2542 * Casey says that we shouldn't have to do 2543 * file system specific code, but it does help 2544 * with keeping it simple. 2545 */ 2546 switch (sbp->s_magic) { 2547 case SMACK_MAGIC: 2548 /* 2549 * Casey says that it's a little embarrassing 2550 * that the smack file system doesn't do 2551 * extended attributes. 2552 */ 2553 final = smack_known_star.smk_known; 2554 break; 2555 case PIPEFS_MAGIC: 2556 /* 2557 * Casey says pipes are easy (?) 2558 */ 2559 final = smack_known_star.smk_known; 2560 break; 2561 case DEVPTS_SUPER_MAGIC: 2562 /* 2563 * devpts seems content with the label of the task. 2564 * Programs that change smack have to treat the 2565 * pty with respect. 2566 */ 2567 final = csp; 2568 break; 2569 case SOCKFS_MAGIC: 2570 /* 2571 * Socket access is controlled by the socket 2572 * structures associated with the task involved. 2573 */ 2574 final = smack_known_star.smk_known; 2575 break; 2576 case PROC_SUPER_MAGIC: 2577 /* 2578 * Casey says procfs appears not to care. 2579 * The superblock default suffices. 2580 */ 2581 break; 2582 case TMPFS_MAGIC: 2583 /* 2584 * Device labels should come from the filesystem, 2585 * but watch out, because they're volitile, 2586 * getting recreated on every reboot. 2587 */ 2588 final = smack_known_star.smk_known; 2589 /* 2590 * No break. 2591 * 2592 * If a smack value has been set we want to use it, 2593 * but since tmpfs isn't giving us the opportunity 2594 * to set mount options simulate setting the 2595 * superblock default. 2596 */ 2597 default: 2598 /* 2599 * This isn't an understood special case. 2600 * Get the value from the xattr. 2601 */ 2602 2603 /* 2604 * UNIX domain sockets use lower level socket data. 2605 */ 2606 if (S_ISSOCK(inode->i_mode)) { 2607 final = smack_known_star.smk_known; 2608 break; 2609 } 2610 /* 2611 * No xattr support means, alas, no SMACK label. 2612 * Use the aforeapplied default. 2613 * It would be curious if the label of the task 2614 * does not match that assigned. 2615 */ 2616 if (inode->i_op->getxattr == NULL) 2617 break; 2618 /* 2619 * Get the dentry for xattr. 2620 */ 2621 dp = dget(opt_dentry); 2622 fetched = smk_fetch(XATTR_NAME_SMACK, inode, dp); 2623 if (fetched != NULL) 2624 final = fetched; 2625 2626 /* 2627 * Transmuting directory 2628 */ 2629 if (S_ISDIR(inode->i_mode)) { 2630 /* 2631 * If this is a new directory and the label was 2632 * transmuted when the inode was initialized 2633 * set the transmute attribute on the directory 2634 * and mark the inode. 2635 * 2636 * If there is a transmute attribute on the 2637 * directory mark the inode. 2638 */ 2639 if (isp->smk_flags & SMK_INODE_CHANGED) { 2640 isp->smk_flags &= ~SMK_INODE_CHANGED; 2641 rc = inode->i_op->setxattr(dp, 2642 XATTR_NAME_SMACKTRANSMUTE, 2643 TRANS_TRUE, TRANS_TRUE_SIZE, 2644 0); 2645 } else { 2646 rc = inode->i_op->getxattr(dp, 2647 XATTR_NAME_SMACKTRANSMUTE, trattr, 2648 TRANS_TRUE_SIZE); 2649 if (rc >= 0 && strncmp(trattr, TRANS_TRUE, 2650 TRANS_TRUE_SIZE) != 0) 2651 rc = -EINVAL; 2652 } 2653 if (rc >= 0) 2654 transflag = SMK_INODE_TRANSMUTE; 2655 } 2656 isp->smk_task = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); 2657 isp->smk_mmap = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp); 2658 2659 dput(dp); 2660 break; 2661 } 2662 2663 if (final == NULL) 2664 isp->smk_inode = csp; 2665 else 2666 isp->smk_inode = final; 2667 2668 isp->smk_flags |= (SMK_INODE_INSTANT | transflag); 2669 2670 unlockandout: 2671 mutex_unlock(&isp->smk_lock); 2672 return; 2673 } 2674 2675 /** 2676 * smack_getprocattr - Smack process attribute access 2677 * @p: the object task 2678 * @name: the name of the attribute in /proc/.../attr 2679 * @value: where to put the result 2680 * 2681 * Places a copy of the task Smack into value 2682 * 2683 * Returns the length of the smack label or an error code 2684 */ 2685 static int smack_getprocattr(struct task_struct *p, char *name, char **value) 2686 { 2687 char *cp; 2688 int slen; 2689 2690 if (strcmp(name, "current") != 0) 2691 return -EINVAL; 2692 2693 cp = kstrdup(smk_of_task(task_security(p)), GFP_KERNEL); 2694 if (cp == NULL) 2695 return -ENOMEM; 2696 2697 slen = strlen(cp); 2698 *value = cp; 2699 return slen; 2700 } 2701 2702 /** 2703 * smack_setprocattr - Smack process attribute setting 2704 * @p: the object task 2705 * @name: the name of the attribute in /proc/.../attr 2706 * @value: the value to set 2707 * @size: the size of the value 2708 * 2709 * Sets the Smack value of the task. Only setting self 2710 * is permitted and only with privilege 2711 * 2712 * Returns the length of the smack label or an error code 2713 */ 2714 static int smack_setprocattr(struct task_struct *p, char *name, 2715 void *value, size_t size) 2716 { 2717 int rc; 2718 struct task_smack *tsp; 2719 struct task_smack *oldtsp; 2720 struct cred *new; 2721 char *newsmack; 2722 2723 /* 2724 * Changing another process' Smack value is too dangerous 2725 * and supports no sane use case. 2726 */ 2727 if (p != current) 2728 return -EPERM; 2729 2730 if (!capable(CAP_MAC_ADMIN)) 2731 return -EPERM; 2732 2733 if (value == NULL || size == 0 || size >= SMK_LONGLABEL) 2734 return -EINVAL; 2735 2736 if (strcmp(name, "current") != 0) 2737 return -EINVAL; 2738 2739 newsmack = smk_import(value, size); 2740 if (newsmack == NULL) 2741 return -EINVAL; 2742 2743 /* 2744 * No process is ever allowed the web ("@") label. 2745 */ 2746 if (newsmack == smack_known_web.smk_known) 2747 return -EPERM; 2748 2749 oldtsp = p->cred->security; 2750 new = prepare_creds(); 2751 if (new == NULL) 2752 return -ENOMEM; 2753 2754 tsp = new_task_smack(newsmack, oldtsp->smk_forked, GFP_KERNEL); 2755 if (tsp == NULL) { 2756 kfree(new); 2757 return -ENOMEM; 2758 } 2759 rc = smk_copy_rules(&tsp->smk_rules, &oldtsp->smk_rules, GFP_KERNEL); 2760 if (rc != 0) 2761 return rc; 2762 2763 new->security = tsp; 2764 commit_creds(new); 2765 return size; 2766 } 2767 2768 /** 2769 * smack_unix_stream_connect - Smack access on UDS 2770 * @sock: one sock 2771 * @other: the other sock 2772 * @newsk: unused 2773 * 2774 * Return 0 if a subject with the smack of sock could access 2775 * an object with the smack of other, otherwise an error code 2776 */ 2777 static int smack_unix_stream_connect(struct sock *sock, 2778 struct sock *other, struct sock *newsk) 2779 { 2780 struct socket_smack *ssp = sock->sk_security; 2781 struct socket_smack *osp = other->sk_security; 2782 struct socket_smack *nsp = newsk->sk_security; 2783 struct smk_audit_info ad; 2784 int rc = 0; 2785 2786 #ifdef CONFIG_AUDIT 2787 struct lsm_network_audit net; 2788 2789 smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); 2790 smk_ad_setfield_u_net_sk(&ad, other); 2791 #endif 2792 2793 if (!capable(CAP_MAC_OVERRIDE)) 2794 rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad); 2795 2796 /* 2797 * Cross reference the peer labels for SO_PEERSEC. 2798 */ 2799 if (rc == 0) { 2800 nsp->smk_packet = ssp->smk_out; 2801 ssp->smk_packet = osp->smk_out; 2802 } 2803 2804 return rc; 2805 } 2806 2807 /** 2808 * smack_unix_may_send - Smack access on UDS 2809 * @sock: one socket 2810 * @other: the other socket 2811 * 2812 * Return 0 if a subject with the smack of sock could access 2813 * an object with the smack of other, otherwise an error code 2814 */ 2815 static int smack_unix_may_send(struct socket *sock, struct socket *other) 2816 { 2817 struct socket_smack *ssp = sock->sk->sk_security; 2818 struct socket_smack *osp = other->sk->sk_security; 2819 struct smk_audit_info ad; 2820 int rc = 0; 2821 2822 #ifdef CONFIG_AUDIT 2823 struct lsm_network_audit net; 2824 2825 smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); 2826 smk_ad_setfield_u_net_sk(&ad, other->sk); 2827 #endif 2828 2829 if (!capable(CAP_MAC_OVERRIDE)) 2830 rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad); 2831 2832 return rc; 2833 } 2834 2835 /** 2836 * smack_socket_sendmsg - Smack check based on destination host 2837 * @sock: the socket 2838 * @msg: the message 2839 * @size: the size of the message 2840 * 2841 * Return 0 if the current subject can write to the destination 2842 * host. This is only a question if the destination is a single 2843 * label host. 2844 */ 2845 static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg, 2846 int size) 2847 { 2848 struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name; 2849 2850 /* 2851 * Perfectly reasonable for this to be NULL 2852 */ 2853 if (sip == NULL || sip->sin_family != AF_INET) 2854 return 0; 2855 2856 return smack_netlabel_send(sock->sk, sip); 2857 } 2858 2859 /** 2860 * smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat pair to smack 2861 * @sap: netlabel secattr 2862 * @ssp: socket security information 2863 * 2864 * Returns a pointer to a Smack label found on the label list. 2865 */ 2866 static char *smack_from_secattr(struct netlbl_lsm_secattr *sap, 2867 struct socket_smack *ssp) 2868 { 2869 struct smack_known *kp; 2870 char *sp; 2871 int found = 0; 2872 2873 if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) { 2874 /* 2875 * Looks like a CIPSO packet. 2876 * If there are flags but no level netlabel isn't 2877 * behaving the way we expect it to. 2878 * 2879 * Look it up in the label table 2880 * Without guidance regarding the smack value 2881 * for the packet fall back on the network 2882 * ambient value. 2883 */ 2884 rcu_read_lock(); 2885 list_for_each_entry(kp, &smack_known_list, list) { 2886 if (sap->attr.mls.lvl != kp->smk_netlabel.attr.mls.lvl) 2887 continue; 2888 if (memcmp(sap->attr.mls.cat, 2889 kp->smk_netlabel.attr.mls.cat, 2890 SMK_CIPSOLEN) != 0) 2891 continue; 2892 found = 1; 2893 break; 2894 } 2895 rcu_read_unlock(); 2896 2897 if (found) 2898 return kp->smk_known; 2899 2900 if (ssp != NULL && ssp->smk_in == smack_known_star.smk_known) 2901 return smack_known_web.smk_known; 2902 return smack_known_star.smk_known; 2903 } 2904 if ((sap->flags & NETLBL_SECATTR_SECID) != 0) { 2905 /* 2906 * Looks like a fallback, which gives us a secid. 2907 */ 2908 sp = smack_from_secid(sap->attr.secid); 2909 /* 2910 * This has got to be a bug because it is 2911 * impossible to specify a fallback without 2912 * specifying the label, which will ensure 2913 * it has a secid, and the only way to get a 2914 * secid is from a fallback. 2915 */ 2916 BUG_ON(sp == NULL); 2917 return sp; 2918 } 2919 /* 2920 * Without guidance regarding the smack value 2921 * for the packet fall back on the network 2922 * ambient value. 2923 */ 2924 return smack_net_ambient; 2925 } 2926 2927 /** 2928 * smack_socket_sock_rcv_skb - Smack packet delivery access check 2929 * @sk: socket 2930 * @skb: packet 2931 * 2932 * Returns 0 if the packet should be delivered, an error code otherwise 2933 */ 2934 static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) 2935 { 2936 struct netlbl_lsm_secattr secattr; 2937 struct socket_smack *ssp = sk->sk_security; 2938 char *csp; 2939 int rc; 2940 struct smk_audit_info ad; 2941 #ifdef CONFIG_AUDIT 2942 struct lsm_network_audit net; 2943 #endif 2944 if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6) 2945 return 0; 2946 2947 /* 2948 * Translate what netlabel gave us. 2949 */ 2950 netlbl_secattr_init(&secattr); 2951 2952 rc = netlbl_skbuff_getattr(skb, sk->sk_family, &secattr); 2953 if (rc == 0) 2954 csp = smack_from_secattr(&secattr, ssp); 2955 else 2956 csp = smack_net_ambient; 2957 2958 netlbl_secattr_destroy(&secattr); 2959 2960 #ifdef CONFIG_AUDIT 2961 smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); 2962 ad.a.u.net->family = sk->sk_family; 2963 ad.a.u.net->netif = skb->skb_iif; 2964 ipv4_skb_to_auditdata(skb, &ad.a, NULL); 2965 #endif 2966 /* 2967 * Receiving a packet requires that the other end 2968 * be able to write here. Read access is not required. 2969 * This is the simplist possible security model 2970 * for networking. 2971 */ 2972 rc = smk_access(csp, ssp->smk_in, MAY_WRITE, &ad); 2973 if (rc != 0) 2974 netlbl_skbuff_err(skb, rc, 0); 2975 return rc; 2976 } 2977 2978 /** 2979 * smack_socket_getpeersec_stream - pull in packet label 2980 * @sock: the socket 2981 * @optval: user's destination 2982 * @optlen: size thereof 2983 * @len: max thereof 2984 * 2985 * returns zero on success, an error code otherwise 2986 */ 2987 static int smack_socket_getpeersec_stream(struct socket *sock, 2988 char __user *optval, 2989 int __user *optlen, unsigned len) 2990 { 2991 struct socket_smack *ssp; 2992 char *rcp = ""; 2993 int slen = 1; 2994 int rc = 0; 2995 2996 ssp = sock->sk->sk_security; 2997 if (ssp->smk_packet != NULL) { 2998 rcp = ssp->smk_packet; 2999 slen = strlen(rcp) + 1; 3000 } 3001 3002 if (slen > len) 3003 rc = -ERANGE; 3004 else if (copy_to_user(optval, rcp, slen) != 0) 3005 rc = -EFAULT; 3006 3007 if (put_user(slen, optlen) != 0) 3008 rc = -EFAULT; 3009 3010 return rc; 3011 } 3012 3013 3014 /** 3015 * smack_socket_getpeersec_dgram - pull in packet label 3016 * @sock: the peer socket 3017 * @skb: packet data 3018 * @secid: pointer to where to put the secid of the packet 3019 * 3020 * Sets the netlabel socket state on sk from parent 3021 */ 3022 static int smack_socket_getpeersec_dgram(struct socket *sock, 3023 struct sk_buff *skb, u32 *secid) 3024 3025 { 3026 struct netlbl_lsm_secattr secattr; 3027 struct socket_smack *ssp = NULL; 3028 char *sp; 3029 int family = PF_UNSPEC; 3030 u32 s = 0; /* 0 is the invalid secid */ 3031 int rc; 3032 3033 if (skb != NULL) { 3034 if (skb->protocol == htons(ETH_P_IP)) 3035 family = PF_INET; 3036 else if (skb->protocol == htons(ETH_P_IPV6)) 3037 family = PF_INET6; 3038 } 3039 if (family == PF_UNSPEC && sock != NULL) 3040 family = sock->sk->sk_family; 3041 3042 if (family == PF_UNIX) { 3043 ssp = sock->sk->sk_security; 3044 s = smack_to_secid(ssp->smk_out); 3045 } else if (family == PF_INET || family == PF_INET6) { 3046 /* 3047 * Translate what netlabel gave us. 3048 */ 3049 if (sock != NULL && sock->sk != NULL) 3050 ssp = sock->sk->sk_security; 3051 netlbl_secattr_init(&secattr); 3052 rc = netlbl_skbuff_getattr(skb, family, &secattr); 3053 if (rc == 0) { 3054 sp = smack_from_secattr(&secattr, ssp); 3055 s = smack_to_secid(sp); 3056 } 3057 netlbl_secattr_destroy(&secattr); 3058 } 3059 *secid = s; 3060 if (s == 0) 3061 return -EINVAL; 3062 return 0; 3063 } 3064 3065 /** 3066 * smack_sock_graft - Initialize a newly created socket with an existing sock 3067 * @sk: child sock 3068 * @parent: parent socket 3069 * 3070 * Set the smk_{in,out} state of an existing sock based on the process that 3071 * is creating the new socket. 3072 */ 3073 static void smack_sock_graft(struct sock *sk, struct socket *parent) 3074 { 3075 struct socket_smack *ssp; 3076 3077 if (sk == NULL || 3078 (sk->sk_family != PF_INET && sk->sk_family != PF_INET6)) 3079 return; 3080 3081 ssp = sk->sk_security; 3082 ssp->smk_in = ssp->smk_out = smk_of_current(); 3083 /* cssp->smk_packet is already set in smack_inet_csk_clone() */ 3084 } 3085 3086 /** 3087 * smack_inet_conn_request - Smack access check on connect 3088 * @sk: socket involved 3089 * @skb: packet 3090 * @req: unused 3091 * 3092 * Returns 0 if a task with the packet label could write to 3093 * the socket, otherwise an error code 3094 */ 3095 static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb, 3096 struct request_sock *req) 3097 { 3098 u16 family = sk->sk_family; 3099 struct smack_known *skp; 3100 struct socket_smack *ssp = sk->sk_security; 3101 struct netlbl_lsm_secattr secattr; 3102 struct sockaddr_in addr; 3103 struct iphdr *hdr; 3104 char *sp; 3105 char *hsp; 3106 int rc; 3107 struct smk_audit_info ad; 3108 #ifdef CONFIG_AUDIT 3109 struct lsm_network_audit net; 3110 #endif 3111 3112 /* handle mapped IPv4 packets arriving via IPv6 sockets */ 3113 if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP)) 3114 family = PF_INET; 3115 3116 netlbl_secattr_init(&secattr); 3117 rc = netlbl_skbuff_getattr(skb, family, &secattr); 3118 if (rc == 0) 3119 sp = smack_from_secattr(&secattr, ssp); 3120 else 3121 sp = smack_known_huh.smk_known; 3122 netlbl_secattr_destroy(&secattr); 3123 3124 #ifdef CONFIG_AUDIT 3125 smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); 3126 ad.a.u.net->family = family; 3127 ad.a.u.net->netif = skb->skb_iif; 3128 ipv4_skb_to_auditdata(skb, &ad.a, NULL); 3129 #endif 3130 /* 3131 * Receiving a packet requires that the other end be able to write 3132 * here. Read access is not required. 3133 */ 3134 rc = smk_access(sp, ssp->smk_in, MAY_WRITE, &ad); 3135 if (rc != 0) 3136 return rc; 3137 3138 /* 3139 * Save the peer's label in the request_sock so we can later setup 3140 * smk_packet in the child socket so that SO_PEERCRED can report it. 3141 */ 3142 req->peer_secid = smack_to_secid(sp); 3143 3144 /* 3145 * We need to decide if we want to label the incoming connection here 3146 * if we do we only need to label the request_sock and the stack will 3147 * propagate the wire-label to the sock when it is created. 3148 */ 3149 hdr = ip_hdr(skb); 3150 addr.sin_addr.s_addr = hdr->saddr; 3151 rcu_read_lock(); 3152 hsp = smack_host_label(&addr); 3153 rcu_read_unlock(); 3154 3155 if (hsp == NULL) { 3156 skp = smk_find_entry(sp); 3157 rc = netlbl_req_setattr(req, &skp->smk_netlabel); 3158 } else 3159 netlbl_req_delattr(req); 3160 3161 return rc; 3162 } 3163 3164 /** 3165 * smack_inet_csk_clone - Copy the connection information to the new socket 3166 * @sk: the new socket 3167 * @req: the connection's request_sock 3168 * 3169 * Transfer the connection's peer label to the newly created socket. 3170 */ 3171 static void smack_inet_csk_clone(struct sock *sk, 3172 const struct request_sock *req) 3173 { 3174 struct socket_smack *ssp = sk->sk_security; 3175 3176 if (req->peer_secid != 0) 3177 ssp->smk_packet = smack_from_secid(req->peer_secid); 3178 else 3179 ssp->smk_packet = NULL; 3180 } 3181 3182 /* 3183 * Key management security hooks 3184 * 3185 * Casey has not tested key support very heavily. 3186 * The permission check is most likely too restrictive. 3187 * If you care about keys please have a look. 3188 */ 3189 #ifdef CONFIG_KEYS 3190 3191 /** 3192 * smack_key_alloc - Set the key security blob 3193 * @key: object 3194 * @cred: the credentials to use 3195 * @flags: unused 3196 * 3197 * No allocation required 3198 * 3199 * Returns 0 3200 */ 3201 static int smack_key_alloc(struct key *key, const struct cred *cred, 3202 unsigned long flags) 3203 { 3204 key->security = smk_of_task(cred->security); 3205 return 0; 3206 } 3207 3208 /** 3209 * smack_key_free - Clear the key security blob 3210 * @key: the object 3211 * 3212 * Clear the blob pointer 3213 */ 3214 static void smack_key_free(struct key *key) 3215 { 3216 key->security = NULL; 3217 } 3218 3219 /* 3220 * smack_key_permission - Smack access on a key 3221 * @key_ref: gets to the object 3222 * @cred: the credentials to use 3223 * @perm: unused 3224 * 3225 * Return 0 if the task has read and write to the object, 3226 * an error code otherwise 3227 */ 3228 static int smack_key_permission(key_ref_t key_ref, 3229 const struct cred *cred, key_perm_t perm) 3230 { 3231 struct key *keyp; 3232 struct smk_audit_info ad; 3233 char *tsp = smk_of_task(cred->security); 3234 3235 keyp = key_ref_to_ptr(key_ref); 3236 if (keyp == NULL) 3237 return -EINVAL; 3238 /* 3239 * If the key hasn't been initialized give it access so that 3240 * it may do so. 3241 */ 3242 if (keyp->security == NULL) 3243 return 0; 3244 /* 3245 * This should not occur 3246 */ 3247 if (tsp == NULL) 3248 return -EACCES; 3249 #ifdef CONFIG_AUDIT 3250 smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY); 3251 ad.a.u.key_struct.key = keyp->serial; 3252 ad.a.u.key_struct.key_desc = keyp->description; 3253 #endif 3254 return smk_access(tsp, keyp->security, 3255 MAY_READWRITE, &ad); 3256 } 3257 #endif /* CONFIG_KEYS */ 3258 3259 /* 3260 * Smack Audit hooks 3261 * 3262 * Audit requires a unique representation of each Smack specific 3263 * rule. This unique representation is used to distinguish the 3264 * object to be audited from remaining kernel objects and also 3265 * works as a glue between the audit hooks. 3266 * 3267 * Since repository entries are added but never deleted, we'll use 3268 * the smack_known label address related to the given audit rule as 3269 * the needed unique representation. This also better fits the smack 3270 * model where nearly everything is a label. 3271 */ 3272 #ifdef CONFIG_AUDIT 3273 3274 /** 3275 * smack_audit_rule_init - Initialize a smack audit rule 3276 * @field: audit rule fields given from user-space (audit.h) 3277 * @op: required testing operator (=, !=, >, <, ...) 3278 * @rulestr: smack label to be audited 3279 * @vrule: pointer to save our own audit rule representation 3280 * 3281 * Prepare to audit cases where (@field @op @rulestr) is true. 3282 * The label to be audited is created if necessay. 3283 */ 3284 static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule) 3285 { 3286 char **rule = (char **)vrule; 3287 *rule = NULL; 3288 3289 if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER) 3290 return -EINVAL; 3291 3292 if (op != Audit_equal && op != Audit_not_equal) 3293 return -EINVAL; 3294 3295 *rule = smk_import(rulestr, 0); 3296 3297 return 0; 3298 } 3299 3300 /** 3301 * smack_audit_rule_known - Distinguish Smack audit rules 3302 * @krule: rule of interest, in Audit kernel representation format 3303 * 3304 * This is used to filter Smack rules from remaining Audit ones. 3305 * If it's proved that this rule belongs to us, the 3306 * audit_rule_match hook will be called to do the final judgement. 3307 */ 3308 static int smack_audit_rule_known(struct audit_krule *krule) 3309 { 3310 struct audit_field *f; 3311 int i; 3312 3313 for (i = 0; i < krule->field_count; i++) { 3314 f = &krule->fields[i]; 3315 3316 if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER) 3317 return 1; 3318 } 3319 3320 return 0; 3321 } 3322 3323 /** 3324 * smack_audit_rule_match - Audit given object ? 3325 * @secid: security id for identifying the object to test 3326 * @field: audit rule flags given from user-space 3327 * @op: required testing operator 3328 * @vrule: smack internal rule presentation 3329 * @actx: audit context associated with the check 3330 * 3331 * The core Audit hook. It's used to take the decision of 3332 * whether to audit or not to audit a given object. 3333 */ 3334 static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule, 3335 struct audit_context *actx) 3336 { 3337 char *smack; 3338 char *rule = vrule; 3339 3340 if (!rule) { 3341 audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR, 3342 "Smack: missing rule\n"); 3343 return -ENOENT; 3344 } 3345 3346 if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER) 3347 return 0; 3348 3349 smack = smack_from_secid(secid); 3350 3351 /* 3352 * No need to do string comparisons. If a match occurs, 3353 * both pointers will point to the same smack_known 3354 * label. 3355 */ 3356 if (op == Audit_equal) 3357 return (rule == smack); 3358 if (op == Audit_not_equal) 3359 return (rule != smack); 3360 3361 return 0; 3362 } 3363 3364 /** 3365 * smack_audit_rule_free - free smack rule representation 3366 * @vrule: rule to be freed. 3367 * 3368 * No memory was allocated. 3369 */ 3370 static void smack_audit_rule_free(void *vrule) 3371 { 3372 /* No-op */ 3373 } 3374 3375 #endif /* CONFIG_AUDIT */ 3376 3377 /** 3378 * smack_secid_to_secctx - return the smack label for a secid 3379 * @secid: incoming integer 3380 * @secdata: destination 3381 * @seclen: how long it is 3382 * 3383 * Exists for networking code. 3384 */ 3385 static int smack_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) 3386 { 3387 char *sp = smack_from_secid(secid); 3388 3389 if (secdata) 3390 *secdata = sp; 3391 *seclen = strlen(sp); 3392 return 0; 3393 } 3394 3395 /** 3396 * smack_secctx_to_secid - return the secid for a smack label 3397 * @secdata: smack label 3398 * @seclen: how long result is 3399 * @secid: outgoing integer 3400 * 3401 * Exists for audit and networking code. 3402 */ 3403 static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid) 3404 { 3405 *secid = smack_to_secid(secdata); 3406 return 0; 3407 } 3408 3409 /** 3410 * smack_release_secctx - don't do anything. 3411 * @secdata: unused 3412 * @seclen: unused 3413 * 3414 * Exists to make sure nothing gets done, and properly 3415 */ 3416 static void smack_release_secctx(char *secdata, u32 seclen) 3417 { 3418 } 3419 3420 static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen) 3421 { 3422 return smack_inode_setsecurity(inode, XATTR_SMACK_SUFFIX, ctx, ctxlen, 0); 3423 } 3424 3425 static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen) 3426 { 3427 return __vfs_setxattr_noperm(dentry, XATTR_NAME_SMACK, ctx, ctxlen, 0); 3428 } 3429 3430 static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen) 3431 { 3432 int len = 0; 3433 len = smack_inode_getsecurity(inode, XATTR_SMACK_SUFFIX, ctx, true); 3434 3435 if (len < 0) 3436 return len; 3437 *ctxlen = len; 3438 return 0; 3439 } 3440 3441 struct security_operations smack_ops = { 3442 .name = "smack", 3443 3444 .ptrace_access_check = smack_ptrace_access_check, 3445 .ptrace_traceme = smack_ptrace_traceme, 3446 .syslog = smack_syslog, 3447 3448 .sb_alloc_security = smack_sb_alloc_security, 3449 .sb_free_security = smack_sb_free_security, 3450 .sb_copy_data = smack_sb_copy_data, 3451 .sb_kern_mount = smack_sb_kern_mount, 3452 .sb_statfs = smack_sb_statfs, 3453 .sb_mount = smack_sb_mount, 3454 .sb_umount = smack_sb_umount, 3455 3456 .bprm_set_creds = smack_bprm_set_creds, 3457 .bprm_committing_creds = smack_bprm_committing_creds, 3458 .bprm_secureexec = smack_bprm_secureexec, 3459 3460 .inode_alloc_security = smack_inode_alloc_security, 3461 .inode_free_security = smack_inode_free_security, 3462 .inode_init_security = smack_inode_init_security, 3463 .inode_link = smack_inode_link, 3464 .inode_unlink = smack_inode_unlink, 3465 .inode_rmdir = smack_inode_rmdir, 3466 .inode_rename = smack_inode_rename, 3467 .inode_permission = smack_inode_permission, 3468 .inode_setattr = smack_inode_setattr, 3469 .inode_getattr = smack_inode_getattr, 3470 .inode_setxattr = smack_inode_setxattr, 3471 .inode_post_setxattr = smack_inode_post_setxattr, 3472 .inode_getxattr = smack_inode_getxattr, 3473 .inode_removexattr = smack_inode_removexattr, 3474 .inode_getsecurity = smack_inode_getsecurity, 3475 .inode_setsecurity = smack_inode_setsecurity, 3476 .inode_listsecurity = smack_inode_listsecurity, 3477 .inode_getsecid = smack_inode_getsecid, 3478 3479 .file_permission = smack_file_permission, 3480 .file_alloc_security = smack_file_alloc_security, 3481 .file_free_security = smack_file_free_security, 3482 .file_ioctl = smack_file_ioctl, 3483 .file_lock = smack_file_lock, 3484 .file_fcntl = smack_file_fcntl, 3485 .file_mmap = smack_file_mmap, 3486 .file_set_fowner = smack_file_set_fowner, 3487 .file_send_sigiotask = smack_file_send_sigiotask, 3488 .file_receive = smack_file_receive, 3489 3490 .file_open = smack_file_open, 3491 3492 .cred_alloc_blank = smack_cred_alloc_blank, 3493 .cred_free = smack_cred_free, 3494 .cred_prepare = smack_cred_prepare, 3495 .cred_transfer = smack_cred_transfer, 3496 .kernel_act_as = smack_kernel_act_as, 3497 .kernel_create_files_as = smack_kernel_create_files_as, 3498 .task_setpgid = smack_task_setpgid, 3499 .task_getpgid = smack_task_getpgid, 3500 .task_getsid = smack_task_getsid, 3501 .task_getsecid = smack_task_getsecid, 3502 .task_setnice = smack_task_setnice, 3503 .task_setioprio = smack_task_setioprio, 3504 .task_getioprio = smack_task_getioprio, 3505 .task_setscheduler = smack_task_setscheduler, 3506 .task_getscheduler = smack_task_getscheduler, 3507 .task_movememory = smack_task_movememory, 3508 .task_kill = smack_task_kill, 3509 .task_wait = smack_task_wait, 3510 .task_to_inode = smack_task_to_inode, 3511 3512 .ipc_permission = smack_ipc_permission, 3513 .ipc_getsecid = smack_ipc_getsecid, 3514 3515 .msg_msg_alloc_security = smack_msg_msg_alloc_security, 3516 .msg_msg_free_security = smack_msg_msg_free_security, 3517 3518 .msg_queue_alloc_security = smack_msg_queue_alloc_security, 3519 .msg_queue_free_security = smack_msg_queue_free_security, 3520 .msg_queue_associate = smack_msg_queue_associate, 3521 .msg_queue_msgctl = smack_msg_queue_msgctl, 3522 .msg_queue_msgsnd = smack_msg_queue_msgsnd, 3523 .msg_queue_msgrcv = smack_msg_queue_msgrcv, 3524 3525 .shm_alloc_security = smack_shm_alloc_security, 3526 .shm_free_security = smack_shm_free_security, 3527 .shm_associate = smack_shm_associate, 3528 .shm_shmctl = smack_shm_shmctl, 3529 .shm_shmat = smack_shm_shmat, 3530 3531 .sem_alloc_security = smack_sem_alloc_security, 3532 .sem_free_security = smack_sem_free_security, 3533 .sem_associate = smack_sem_associate, 3534 .sem_semctl = smack_sem_semctl, 3535 .sem_semop = smack_sem_semop, 3536 3537 .d_instantiate = smack_d_instantiate, 3538 3539 .getprocattr = smack_getprocattr, 3540 .setprocattr = smack_setprocattr, 3541 3542 .unix_stream_connect = smack_unix_stream_connect, 3543 .unix_may_send = smack_unix_may_send, 3544 3545 .socket_post_create = smack_socket_post_create, 3546 .socket_connect = smack_socket_connect, 3547 .socket_sendmsg = smack_socket_sendmsg, 3548 .socket_sock_rcv_skb = smack_socket_sock_rcv_skb, 3549 .socket_getpeersec_stream = smack_socket_getpeersec_stream, 3550 .socket_getpeersec_dgram = smack_socket_getpeersec_dgram, 3551 .sk_alloc_security = smack_sk_alloc_security, 3552 .sk_free_security = smack_sk_free_security, 3553 .sock_graft = smack_sock_graft, 3554 .inet_conn_request = smack_inet_conn_request, 3555 .inet_csk_clone = smack_inet_csk_clone, 3556 3557 /* key management security hooks */ 3558 #ifdef CONFIG_KEYS 3559 .key_alloc = smack_key_alloc, 3560 .key_free = smack_key_free, 3561 .key_permission = smack_key_permission, 3562 #endif /* CONFIG_KEYS */ 3563 3564 /* Audit hooks */ 3565 #ifdef CONFIG_AUDIT 3566 .audit_rule_init = smack_audit_rule_init, 3567 .audit_rule_known = smack_audit_rule_known, 3568 .audit_rule_match = smack_audit_rule_match, 3569 .audit_rule_free = smack_audit_rule_free, 3570 #endif /* CONFIG_AUDIT */ 3571 3572 .secid_to_secctx = smack_secid_to_secctx, 3573 .secctx_to_secid = smack_secctx_to_secid, 3574 .release_secctx = smack_release_secctx, 3575 .inode_notifysecctx = smack_inode_notifysecctx, 3576 .inode_setsecctx = smack_inode_setsecctx, 3577 .inode_getsecctx = smack_inode_getsecctx, 3578 }; 3579 3580 3581 static __init void init_smack_known_list(void) 3582 { 3583 /* 3584 * Initialize rule list locks 3585 */ 3586 mutex_init(&smack_known_huh.smk_rules_lock); 3587 mutex_init(&smack_known_hat.smk_rules_lock); 3588 mutex_init(&smack_known_floor.smk_rules_lock); 3589 mutex_init(&smack_known_star.smk_rules_lock); 3590 mutex_init(&smack_known_invalid.smk_rules_lock); 3591 mutex_init(&smack_known_web.smk_rules_lock); 3592 /* 3593 * Initialize rule lists 3594 */ 3595 INIT_LIST_HEAD(&smack_known_huh.smk_rules); 3596 INIT_LIST_HEAD(&smack_known_hat.smk_rules); 3597 INIT_LIST_HEAD(&smack_known_star.smk_rules); 3598 INIT_LIST_HEAD(&smack_known_floor.smk_rules); 3599 INIT_LIST_HEAD(&smack_known_invalid.smk_rules); 3600 INIT_LIST_HEAD(&smack_known_web.smk_rules); 3601 /* 3602 * Create the known labels list 3603 */ 3604 list_add(&smack_known_huh.list, &smack_known_list); 3605 list_add(&smack_known_hat.list, &smack_known_list); 3606 list_add(&smack_known_star.list, &smack_known_list); 3607 list_add(&smack_known_floor.list, &smack_known_list); 3608 list_add(&smack_known_invalid.list, &smack_known_list); 3609 list_add(&smack_known_web.list, &smack_known_list); 3610 } 3611 3612 /** 3613 * smack_init - initialize the smack system 3614 * 3615 * Returns 0 3616 */ 3617 static __init int smack_init(void) 3618 { 3619 struct cred *cred; 3620 struct task_smack *tsp; 3621 3622 if (!security_module_enable(&smack_ops)) 3623 return 0; 3624 3625 tsp = new_task_smack(smack_known_floor.smk_known, 3626 smack_known_floor.smk_known, GFP_KERNEL); 3627 if (tsp == NULL) 3628 return -ENOMEM; 3629 3630 printk(KERN_INFO "Smack: Initializing.\n"); 3631 3632 /* 3633 * Set the security state for the initial task. 3634 */ 3635 cred = (struct cred *) current->cred; 3636 cred->security = tsp; 3637 3638 /* initialize the smack_known_list */ 3639 init_smack_known_list(); 3640 3641 /* 3642 * Register with LSM 3643 */ 3644 if (register_security(&smack_ops)) 3645 panic("smack: Unable to register with kernel.\n"); 3646 3647 return 0; 3648 } 3649 3650 /* 3651 * Smack requires early initialization in order to label 3652 * all processes and objects when they are created. 3653 */ 3654 security_initcall(smack_init); 3655