linux/security/smack/smackfs.c
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   1/*
   2 * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
   3 *
   4 *      This program is free software; you can redistribute it and/or modify
   5 *      it under the terms of the GNU General Public License as published by
   6 *      the Free Software Foundation, version 2.
   7 *
   8 * Authors:
   9 *      Casey Schaufler <casey@schaufler-ca.com>
  10 *      Ahmed S. Darwish <darwish.07@gmail.com>
  11 *
  12 * Special thanks to the authors of selinuxfs.
  13 *
  14 *      Karl MacMillan <kmacmillan@tresys.com>
  15 *      James Morris <jmorris@redhat.com>
  16 *
  17 */
  18
  19#include <linux/kernel.h>
  20#include <linux/vmalloc.h>
  21#include <linux/security.h>
  22#include <linux/mutex.h>
  23#include <net/netlabel.h>
  24#include <net/cipso_ipv4.h>
  25#include <linux/seq_file.h>
  26#include <linux/ctype.h>
  27#include <linux/audit.h>
  28#include "smack.h"
  29
  30/*
  31 * smackfs pseudo filesystem.
  32 */
  33
  34enum smk_inos {
  35        SMK_ROOT_INO    = 2,
  36        SMK_LOAD        = 3,    /* load policy */
  37        SMK_CIPSO       = 4,    /* load label -> CIPSO mapping */
  38        SMK_DOI         = 5,    /* CIPSO DOI */
  39        SMK_DIRECT      = 6,    /* CIPSO level indicating direct label */
  40        SMK_AMBIENT     = 7,    /* internet ambient label */
  41        SMK_NLTYPE      = 8,    /* label scheme to use by default */
  42        SMK_ONLYCAP     = 9,    /* the only "capable" label */
  43};
  44
  45/*
  46 * List locks
  47 */
  48static DEFINE_MUTEX(smack_list_lock);
  49static DEFINE_MUTEX(smack_cipso_lock);
  50static DEFINE_MUTEX(smack_ambient_lock);
  51
  52/*
  53 * This is the "ambient" label for network traffic.
  54 * If it isn't somehow marked, use this.
  55 * It can be reset via smackfs/ambient
  56 */
  57char *smack_net_ambient = smack_known_floor.smk_known;
  58
  59/*
  60 * This is the default packet marking scheme for network traffic.
  61 * It can be reset via smackfs/nltype
  62 */
  63int smack_net_nltype = NETLBL_NLTYPE_CIPSOV4;
  64
  65/*
  66 * This is the level in a CIPSO header that indicates a
  67 * smack label is contained directly in the category set.
  68 * It can be reset via smackfs/direct
  69 */
  70int smack_cipso_direct = SMACK_CIPSO_DIRECT_DEFAULT;
  71
  72/*
  73 * Unless a process is running with this label even
  74 * having CAP_MAC_OVERRIDE isn't enough to grant
  75 * privilege to violate MAC policy. If no label is
  76 * designated (the NULL case) capabilities apply to
  77 * everyone. It is expected that the hat (^) label
  78 * will be used if any label is used.
  79 */
  80char *smack_onlycap;
  81
  82static int smk_cipso_doi_value = SMACK_CIPSO_DOI_DEFAULT;
  83struct smk_list_entry *smack_list;
  84
  85#define SEQ_READ_FINISHED       1
  86
  87/*
  88 * Values for parsing cipso rules
  89 * SMK_DIGITLEN: Length of a digit field in a rule.
  90 * SMK_CIPSOMIN: Minimum possible cipso rule length.
  91 * SMK_CIPSOMAX: Maximum possible cipso rule length.
  92 */
  93#define SMK_DIGITLEN 4
  94#define SMK_CIPSOMIN (SMK_LABELLEN + 2 * SMK_DIGITLEN)
  95#define SMK_CIPSOMAX (SMK_CIPSOMIN + SMACK_CIPSO_MAXCATNUM * SMK_DIGITLEN)
  96
  97/*
  98 * Values for parsing MAC rules
  99 * SMK_ACCESS: Maximum possible combination of access permissions
 100 * SMK_ACCESSLEN: Maximum length for a rule access field
 101 * SMK_LOADLEN: Smack rule length
 102 */
 103#define SMK_ACCESS    "rwxa"
 104#define SMK_ACCESSLEN (sizeof(SMK_ACCESS) - 1)
 105#define SMK_LOADLEN   (SMK_LABELLEN + SMK_LABELLEN + SMK_ACCESSLEN)
 106
 107
 108/*
 109 * Seq_file read operations for /smack/load
 110 */
 111
 112static void *load_seq_start(struct seq_file *s, loff_t *pos)
 113{
 114        if (*pos == SEQ_READ_FINISHED)
 115                return NULL;
 116
 117        return smack_list;
 118}
 119
 120static void *load_seq_next(struct seq_file *s, void *v, loff_t *pos)
 121{
 122        struct smk_list_entry *skp = ((struct smk_list_entry *) v)->smk_next;
 123
 124        if (skp == NULL)
 125                *pos = SEQ_READ_FINISHED;
 126
 127        return skp;
 128}
 129
 130static int load_seq_show(struct seq_file *s, void *v)
 131{
 132        struct smk_list_entry *slp = (struct smk_list_entry *) v;
 133        struct smack_rule *srp = &slp->smk_rule;
 134
 135        seq_printf(s, "%s %s", (char *)srp->smk_subject,
 136                   (char *)srp->smk_object);
 137
 138        seq_putc(s, ' ');
 139
 140        if (srp->smk_access & MAY_READ)
 141                seq_putc(s, 'r');
 142        if (srp->smk_access & MAY_WRITE)
 143                seq_putc(s, 'w');
 144        if (srp->smk_access & MAY_EXEC)
 145                seq_putc(s, 'x');
 146        if (srp->smk_access & MAY_APPEND)
 147                seq_putc(s, 'a');
 148        if (srp->smk_access == 0)
 149                seq_putc(s, '-');
 150
 151        seq_putc(s, '\n');
 152
 153        return 0;
 154}
 155
 156static void load_seq_stop(struct seq_file *s, void *v)
 157{
 158        /* No-op */
 159}
 160
 161static struct seq_operations load_seq_ops = {
 162        .start = load_seq_start,
 163        .next  = load_seq_next,
 164        .show  = load_seq_show,
 165        .stop  = load_seq_stop,
 166};
 167
 168/**
 169 * smk_open_load - open() for /smack/load
 170 * @inode: inode structure representing file
 171 * @file: "load" file pointer
 172 *
 173 * For reading, use load_seq_* seq_file reading operations.
 174 */
 175static int smk_open_load(struct inode *inode, struct file *file)
 176{
 177        return seq_open(file, &load_seq_ops);
 178}
 179
 180/**
 181 * smk_set_access - add a rule to the rule list
 182 * @srp: the new rule to add
 183 *
 184 * Looks through the current subject/object/access list for
 185 * the subject/object pair and replaces the access that was
 186 * there. If the pair isn't found add it with the specified
 187 * access.
 188 */
 189static void smk_set_access(struct smack_rule *srp)
 190{
 191        struct smk_list_entry *sp;
 192        struct smk_list_entry *newp;
 193
 194        mutex_lock(&smack_list_lock);
 195
 196        for (sp = smack_list; sp != NULL; sp = sp->smk_next)
 197                if (sp->smk_rule.smk_subject == srp->smk_subject &&
 198                    sp->smk_rule.smk_object == srp->smk_object) {
 199                        sp->smk_rule.smk_access = srp->smk_access;
 200                        break;
 201                }
 202
 203        if (sp == NULL) {
 204                newp = kzalloc(sizeof(struct smk_list_entry), GFP_KERNEL);
 205                newp->smk_rule = *srp;
 206                newp->smk_next = smack_list;
 207                smack_list = newp;
 208        }
 209
 210        mutex_unlock(&smack_list_lock);
 211
 212        return;
 213}
 214
 215/**
 216 * smk_write_load - write() for /smack/load
 217 * @filp: file pointer, not actually used
 218 * @buf: where to get the data from
 219 * @count: bytes sent
 220 * @ppos: where to start - must be 0
 221 *
 222 * Get one smack access rule from above.
 223 * The format is exactly:
 224 *     char subject[SMK_LABELLEN]
 225 *     char object[SMK_LABELLEN]
 226 *     char access[SMK_ACCESSLEN]
 227 *
 228 * writes must be SMK_LABELLEN+SMK_LABELLEN+SMK_ACCESSLEN bytes.
 229 */
 230static ssize_t smk_write_load(struct file *file, const char __user *buf,
 231                              size_t count, loff_t *ppos)
 232{
 233        struct smack_rule rule;
 234        char *data;
 235        int rc = -EINVAL;
 236
 237        /*
 238         * Must have privilege.
 239         * No partial writes.
 240         * Enough data must be present.
 241         */
 242        if (!capable(CAP_MAC_ADMIN))
 243                return -EPERM;
 244        if (*ppos != 0)
 245                return -EINVAL;
 246        if (count != SMK_LOADLEN)
 247                return -EINVAL;
 248
 249        data = kzalloc(count, GFP_KERNEL);
 250        if (data == NULL)
 251                return -ENOMEM;
 252
 253        if (copy_from_user(data, buf, count) != 0) {
 254                rc = -EFAULT;
 255                goto out;
 256        }
 257
 258        rule.smk_subject = smk_import(data, 0);
 259        if (rule.smk_subject == NULL)
 260                goto out;
 261
 262        rule.smk_object = smk_import(data + SMK_LABELLEN, 0);
 263        if (rule.smk_object == NULL)
 264                goto out;
 265
 266        rule.smk_access = 0;
 267
 268        switch (data[SMK_LABELLEN + SMK_LABELLEN]) {
 269        case '-':
 270                break;
 271        case 'r':
 272        case 'R':
 273                rule.smk_access |= MAY_READ;
 274                break;
 275        default:
 276                goto out;
 277        }
 278
 279        switch (data[SMK_LABELLEN + SMK_LABELLEN + 1]) {
 280        case '-':
 281                break;
 282        case 'w':
 283        case 'W':
 284                rule.smk_access |= MAY_WRITE;
 285                break;
 286        default:
 287                goto out;
 288        }
 289
 290        switch (data[SMK_LABELLEN + SMK_LABELLEN + 2]) {
 291        case '-':
 292                break;
 293        case 'x':
 294        case 'X':
 295                rule.smk_access |= MAY_EXEC;
 296                break;
 297        default:
 298                goto out;
 299        }
 300
 301        switch (data[SMK_LABELLEN + SMK_LABELLEN + 3]) {
 302        case '-':
 303                break;
 304        case 'a':
 305        case 'A':
 306                rule.smk_access |= MAY_READ;
 307                break;
 308        default:
 309                goto out;
 310        }
 311
 312        smk_set_access(&rule);
 313        rc = count;
 314
 315out:
 316        kfree(data);
 317        return rc;
 318}
 319
 320static const struct file_operations smk_load_ops = {
 321        .open           = smk_open_load,
 322        .read           = seq_read,
 323        .llseek         = seq_lseek,
 324        .write          = smk_write_load,
 325        .release        = seq_release,
 326};
 327
 328/**
 329 * smk_cipso_doi - initialize the CIPSO domain
 330 */
 331static void smk_cipso_doi(void)
 332{
 333        int rc;
 334        struct cipso_v4_doi *doip;
 335        struct netlbl_audit audit_info;
 336
 337        audit_info.loginuid = audit_get_loginuid(current);
 338        audit_info.sessionid = audit_get_sessionid(current);
 339        audit_info.secid = smack_to_secid(current->security);
 340
 341        rc = netlbl_cfg_map_del(NULL, &audit_info);
 342        if (rc != 0)
 343                printk(KERN_WARNING "%s:%d remove rc = %d\n",
 344                       __func__, __LINE__, rc);
 345
 346        doip = kmalloc(sizeof(struct cipso_v4_doi), GFP_KERNEL);
 347        if (doip == NULL)
 348                panic("smack:  Failed to initialize cipso DOI.\n");
 349        doip->map.std = NULL;
 350        doip->doi = smk_cipso_doi_value;
 351        doip->type = CIPSO_V4_MAP_PASS;
 352        doip->tags[0] = CIPSO_V4_TAG_RBITMAP;
 353        for (rc = 1; rc < CIPSO_V4_TAG_MAXCNT; rc++)
 354                doip->tags[rc] = CIPSO_V4_TAG_INVALID;
 355
 356        rc = netlbl_cfg_cipsov4_add_map(doip, NULL, &audit_info);
 357        if (rc != 0) {
 358                printk(KERN_WARNING "%s:%d add rc = %d\n",
 359                       __func__, __LINE__, rc);
 360                kfree(doip);
 361        }
 362}
 363
 364/**
 365 * smk_unlbl_ambient - initialize the unlabeled domain
 366 */
 367static void smk_unlbl_ambient(char *oldambient)
 368{
 369        int rc;
 370        struct netlbl_audit audit_info;
 371
 372        audit_info.loginuid = audit_get_loginuid(current);
 373        audit_info.sessionid = audit_get_sessionid(current);
 374        audit_info.secid = smack_to_secid(current->security);
 375
 376        if (oldambient != NULL) {
 377                rc = netlbl_cfg_map_del(oldambient, &audit_info);
 378                if (rc != 0)
 379                        printk(KERN_WARNING "%s:%d remove rc = %d\n",
 380                               __func__, __LINE__, rc);
 381        }
 382
 383        rc = netlbl_cfg_unlbl_add_map(smack_net_ambient, &audit_info);
 384        if (rc != 0)
 385                printk(KERN_WARNING "%s:%d add rc = %d\n",
 386                       __func__, __LINE__, rc);
 387}
 388
 389/*
 390 * Seq_file read operations for /smack/cipso
 391 */
 392
 393static void *cipso_seq_start(struct seq_file *s, loff_t *pos)
 394{
 395        if (*pos == SEQ_READ_FINISHED)
 396                return NULL;
 397
 398        return smack_known;
 399}
 400
 401static void *cipso_seq_next(struct seq_file *s, void *v, loff_t *pos)
 402{
 403        struct smack_known *skp = ((struct smack_known *) v)->smk_next;
 404
 405        /*
 406         * Omit labels with no associated cipso value
 407         */
 408        while (skp != NULL && !skp->smk_cipso)
 409                skp = skp->smk_next;
 410
 411        if (skp == NULL)
 412                *pos = SEQ_READ_FINISHED;
 413
 414        return skp;
 415}
 416
 417/*
 418 * Print cipso labels in format:
 419 * label level[/cat[,cat]]
 420 */
 421static int cipso_seq_show(struct seq_file *s, void *v)
 422{
 423        struct smack_known *skp = (struct smack_known *) v;
 424        struct smack_cipso *scp = skp->smk_cipso;
 425        char *cbp;
 426        char sep = '/';
 427        int cat = 1;
 428        int i;
 429        unsigned char m;
 430
 431        if (scp == NULL)
 432                return 0;
 433
 434        seq_printf(s, "%s %3d", (char *)&skp->smk_known, scp->smk_level);
 435
 436        cbp = scp->smk_catset;
 437        for (i = 0; i < SMK_LABELLEN; i++)
 438                for (m = 0x80; m != 0; m >>= 1) {
 439                        if (m & cbp[i]) {
 440                                seq_printf(s, "%c%d", sep, cat);
 441                                sep = ',';
 442                        }
 443                        cat++;
 444                }
 445
 446        seq_putc(s, '\n');
 447
 448        return 0;
 449}
 450
 451static void cipso_seq_stop(struct seq_file *s, void *v)
 452{
 453        /* No-op */
 454}
 455
 456static struct seq_operations cipso_seq_ops = {
 457        .start = cipso_seq_start,
 458        .stop  = cipso_seq_stop,
 459        .next  = cipso_seq_next,
 460        .show  = cipso_seq_show,
 461};
 462
 463/**
 464 * smk_open_cipso - open() for /smack/cipso
 465 * @inode: inode structure representing file
 466 * @file: "cipso" file pointer
 467 *
 468 * Connect our cipso_seq_* operations with /smack/cipso
 469 * file_operations
 470 */
 471static int smk_open_cipso(struct inode *inode, struct file *file)
 472{
 473        return seq_open(file, &cipso_seq_ops);
 474}
 475
 476/**
 477 * smk_write_cipso - write() for /smack/cipso
 478 * @filp: file pointer, not actually used
 479 * @buf: where to get the data from
 480 * @count: bytes sent
 481 * @ppos: where to start
 482 *
 483 * Accepts only one cipso rule per write call.
 484 * Returns number of bytes written or error code, as appropriate
 485 */
 486static ssize_t smk_write_cipso(struct file *file, const char __user *buf,
 487                               size_t count, loff_t *ppos)
 488{
 489        struct smack_known *skp;
 490        struct smack_cipso *scp = NULL;
 491        char mapcatset[SMK_LABELLEN];
 492        int maplevel;
 493        int cat;
 494        int catlen;
 495        ssize_t rc = -EINVAL;
 496        char *data = NULL;
 497        char *rule;
 498        int ret;
 499        int i;
 500
 501        /*
 502         * Must have privilege.
 503         * No partial writes.
 504         * Enough data must be present.
 505         */
 506        if (!capable(CAP_MAC_ADMIN))
 507                return -EPERM;
 508        if (*ppos != 0)
 509                return -EINVAL;
 510        if (count < SMK_CIPSOMIN || count > SMK_CIPSOMAX)
 511                return -EINVAL;
 512
 513        data = kzalloc(count + 1, GFP_KERNEL);
 514        if (data == NULL)
 515                return -ENOMEM;
 516
 517        if (copy_from_user(data, buf, count) != 0) {
 518                rc = -EFAULT;
 519                goto unlockedout;
 520        }
 521
 522        data[count] = '\0';
 523        rule = data;
 524        /*
 525         * Only allow one writer at a time. Writes should be
 526         * quite rare and small in any case.
 527         */
 528        mutex_lock(&smack_cipso_lock);
 529
 530        skp = smk_import_entry(rule, 0);
 531        if (skp == NULL)
 532                goto out;
 533
 534        rule += SMK_LABELLEN;;
 535        ret = sscanf(rule, "%d", &maplevel);
 536        if (ret != 1 || maplevel > SMACK_CIPSO_MAXLEVEL)
 537                goto out;
 538
 539        rule += SMK_DIGITLEN;
 540        ret = sscanf(rule, "%d", &catlen);
 541        if (ret != 1 || catlen > SMACK_CIPSO_MAXCATNUM)
 542                goto out;
 543
 544        if (count != (SMK_CIPSOMIN + catlen * SMK_DIGITLEN))
 545                goto out;
 546
 547        memset(mapcatset, 0, sizeof(mapcatset));
 548
 549        for (i = 0; i < catlen; i++) {
 550                rule += SMK_DIGITLEN;
 551                ret = sscanf(rule, "%d", &cat);
 552                if (ret != 1 || cat > SMACK_CIPSO_MAXCATVAL)
 553                        goto out;
 554
 555                smack_catset_bit(cat, mapcatset);
 556        }
 557
 558        if (skp->smk_cipso == NULL) {
 559                scp = kzalloc(sizeof(struct smack_cipso), GFP_KERNEL);
 560                if (scp == NULL) {
 561                        rc = -ENOMEM;
 562                        goto out;
 563                }
 564        }
 565
 566        spin_lock_bh(&skp->smk_cipsolock);
 567
 568        if (scp == NULL)
 569                scp = skp->smk_cipso;
 570        else
 571                skp->smk_cipso = scp;
 572
 573        scp->smk_level = maplevel;
 574        memcpy(scp->smk_catset, mapcatset, sizeof(mapcatset));
 575
 576        spin_unlock_bh(&skp->smk_cipsolock);
 577
 578        rc = count;
 579out:
 580        mutex_unlock(&smack_cipso_lock);
 581unlockedout:
 582        kfree(data);
 583        return rc;
 584}
 585
 586static const struct file_operations smk_cipso_ops = {
 587        .open           = smk_open_cipso,
 588        .read           = seq_read,
 589        .llseek         = seq_lseek,
 590        .write          = smk_write_cipso,
 591        .release        = seq_release,
 592};
 593
 594/**
 595 * smk_read_doi - read() for /smack/doi
 596 * @filp: file pointer, not actually used
 597 * @buf: where to put the result
 598 * @count: maximum to send along
 599 * @ppos: where to start
 600 *
 601 * Returns number of bytes read or error code, as appropriate
 602 */
 603static ssize_t smk_read_doi(struct file *filp, char __user *buf,
 604                            size_t count, loff_t *ppos)
 605{
 606        char temp[80];
 607        ssize_t rc;
 608
 609        if (*ppos != 0)
 610                return 0;
 611
 612        sprintf(temp, "%d", smk_cipso_doi_value);
 613        rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
 614
 615        return rc;
 616}
 617
 618/**
 619 * smk_write_doi - write() for /smack/doi
 620 * @filp: file pointer, not actually used
 621 * @buf: where to get the data from
 622 * @count: bytes sent
 623 * @ppos: where to start
 624 *
 625 * Returns number of bytes written or error code, as appropriate
 626 */
 627static ssize_t smk_write_doi(struct file *file, const char __user *buf,
 628                             size_t count, loff_t *ppos)
 629{
 630        char temp[80];
 631        int i;
 632
 633        if (!capable(CAP_MAC_ADMIN))
 634                return -EPERM;
 635
 636        if (count >= sizeof(temp) || count == 0)
 637                return -EINVAL;
 638
 639        if (copy_from_user(temp, buf, count) != 0)
 640                return -EFAULT;
 641
 642        temp[count] = '\0';
 643
 644        if (sscanf(temp, "%d", &i) != 1)
 645                return -EINVAL;
 646
 647        smk_cipso_doi_value = i;
 648
 649        smk_cipso_doi();
 650
 651        return count;
 652}
 653
 654static const struct file_operations smk_doi_ops = {
 655        .read           = smk_read_doi,
 656        .write          = smk_write_doi,
 657};
 658
 659/**
 660 * smk_read_direct - read() for /smack/direct
 661 * @filp: file pointer, not actually used
 662 * @buf: where to put the result
 663 * @count: maximum to send along
 664 * @ppos: where to start
 665 *
 666 * Returns number of bytes read or error code, as appropriate
 667 */
 668static ssize_t smk_read_direct(struct file *filp, char __user *buf,
 669                               size_t count, loff_t *ppos)
 670{
 671        char temp[80];
 672        ssize_t rc;
 673
 674        if (*ppos != 0)
 675                return 0;
 676
 677        sprintf(temp, "%d", smack_cipso_direct);
 678        rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
 679
 680        return rc;
 681}
 682
 683/**
 684 * smk_write_direct - write() for /smack/direct
 685 * @filp: file pointer, not actually used
 686 * @buf: where to get the data from
 687 * @count: bytes sent
 688 * @ppos: where to start
 689 *
 690 * Returns number of bytes written or error code, as appropriate
 691 */
 692static ssize_t smk_write_direct(struct file *file, const char __user *buf,
 693                                size_t count, loff_t *ppos)
 694{
 695        char temp[80];
 696        int i;
 697
 698        if (!capable(CAP_MAC_ADMIN))
 699                return -EPERM;
 700
 701        if (count >= sizeof(temp) || count == 0)
 702                return -EINVAL;
 703
 704        if (copy_from_user(temp, buf, count) != 0)
 705                return -EFAULT;
 706
 707        temp[count] = '\0';
 708
 709        if (sscanf(temp, "%d", &i) != 1)
 710                return -EINVAL;
 711
 712        smack_cipso_direct = i;
 713
 714        return count;
 715}
 716
 717static const struct file_operations smk_direct_ops = {
 718        .read           = smk_read_direct,
 719        .write          = smk_write_direct,
 720};
 721
 722/**
 723 * smk_read_ambient - read() for /smack/ambient
 724 * @filp: file pointer, not actually used
 725 * @buf: where to put the result
 726 * @cn: maximum to send along
 727 * @ppos: where to start
 728 *
 729 * Returns number of bytes read or error code, as appropriate
 730 */
 731static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 732                                size_t cn, loff_t *ppos)
 733{
 734        ssize_t rc;
 735        int asize;
 736
 737        if (*ppos != 0)
 738                return 0;
 739        /*
 740         * Being careful to avoid a problem in the case where
 741         * smack_net_ambient gets changed in midstream.
 742         */
 743        mutex_lock(&smack_ambient_lock);
 744
 745        asize = strlen(smack_net_ambient) + 1;
 746
 747        if (cn >= asize)
 748                rc = simple_read_from_buffer(buf, cn, ppos,
 749                                             smack_net_ambient, asize);
 750        else
 751                rc = -EINVAL;
 752
 753        mutex_unlock(&smack_ambient_lock);
 754
 755        return rc;
 756}
 757
 758/**
 759 * smk_write_ambient - write() for /smack/ambient
 760 * @filp: file pointer, not actually used
 761 * @buf: where to get the data from
 762 * @count: bytes sent
 763 * @ppos: where to start
 764 *
 765 * Returns number of bytes written or error code, as appropriate
 766 */
 767static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
 768                                 size_t count, loff_t *ppos)
 769{
 770        char in[SMK_LABELLEN];
 771        char *oldambient;
 772        char *smack;
 773
 774        if (!capable(CAP_MAC_ADMIN))
 775                return -EPERM;
 776
 777        if (count >= SMK_LABELLEN)
 778                return -EINVAL;
 779
 780        if (copy_from_user(in, buf, count) != 0)
 781                return -EFAULT;
 782
 783        smack = smk_import(in, count);
 784        if (smack == NULL)
 785                return -EINVAL;
 786
 787        mutex_lock(&smack_ambient_lock);
 788
 789        oldambient = smack_net_ambient;
 790        smack_net_ambient = smack;
 791        smk_unlbl_ambient(oldambient);
 792
 793        mutex_unlock(&smack_ambient_lock);
 794
 795        return count;
 796}
 797
 798static const struct file_operations smk_ambient_ops = {
 799        .read           = smk_read_ambient,
 800        .write          = smk_write_ambient,
 801};
 802
 803/**
 804 * smk_read_onlycap - read() for /smack/onlycap
 805 * @filp: file pointer, not actually used
 806 * @buf: where to put the result
 807 * @cn: maximum to send along
 808 * @ppos: where to start
 809 *
 810 * Returns number of bytes read or error code, as appropriate
 811 */
 812static ssize_t smk_read_onlycap(struct file *filp, char __user *buf,
 813                                size_t cn, loff_t *ppos)
 814{
 815        char *smack = "";
 816        ssize_t rc = -EINVAL;
 817        int asize;
 818
 819        if (*ppos != 0)
 820                return 0;
 821
 822        if (smack_onlycap != NULL)
 823                smack = smack_onlycap;
 824
 825        asize = strlen(smack) + 1;
 826
 827        if (cn >= asize)
 828                rc = simple_read_from_buffer(buf, cn, ppos, smack, asize);
 829
 830        return rc;
 831}
 832
 833/**
 834 * smk_write_onlycap - write() for /smack/onlycap
 835 * @filp: file pointer, not actually used
 836 * @buf: where to get the data from
 837 * @count: bytes sent
 838 * @ppos: where to start
 839 *
 840 * Returns number of bytes written or error code, as appropriate
 841 */
 842static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 843                                 size_t count, loff_t *ppos)
 844{
 845        char in[SMK_LABELLEN];
 846        char *sp = current->security;
 847
 848        if (!capable(CAP_MAC_ADMIN))
 849                return -EPERM;
 850
 851        /*
 852         * This can be done using smk_access() but is done
 853         * explicitly for clarity. The smk_access() implementation
 854         * would use smk_access(smack_onlycap, MAY_WRITE)
 855         */
 856        if (smack_onlycap != NULL && smack_onlycap != sp)
 857                return -EPERM;
 858
 859        if (count >= SMK_LABELLEN)
 860                return -EINVAL;
 861
 862        if (copy_from_user(in, buf, count) != 0)
 863                return -EFAULT;
 864
 865        /*
 866         * Should the null string be passed in unset the onlycap value.
 867         * This seems like something to be careful with as usually
 868         * smk_import only expects to return NULL for errors. It
 869         * is usually the case that a nullstring or "\n" would be
 870         * bad to pass to smk_import but in fact this is useful here.
 871         */
 872        smack_onlycap = smk_import(in, count);
 873
 874        return count;
 875}
 876
 877static const struct file_operations smk_onlycap_ops = {
 878        .read           = smk_read_onlycap,
 879        .write          = smk_write_onlycap,
 880};
 881
 882struct option_names {
 883        int     o_number;
 884        char    *o_name;
 885        char    *o_alias;
 886};
 887
 888static struct option_names netlbl_choices[] = {
 889        { NETLBL_NLTYPE_RIPSO,
 890                NETLBL_NLTYPE_RIPSO_NAME,       "ripso" },
 891        { NETLBL_NLTYPE_CIPSOV4,
 892                NETLBL_NLTYPE_CIPSOV4_NAME,     "cipsov4" },
 893        { NETLBL_NLTYPE_CIPSOV4,
 894                NETLBL_NLTYPE_CIPSOV4_NAME,     "cipso" },
 895        { NETLBL_NLTYPE_CIPSOV6,
 896                NETLBL_NLTYPE_CIPSOV6_NAME,     "cipsov6" },
 897        { NETLBL_NLTYPE_UNLABELED,
 898                NETLBL_NLTYPE_UNLABELED_NAME,   "unlabeled" },
 899};
 900
 901/**
 902 * smk_read_nltype - read() for /smack/nltype
 903 * @filp: file pointer, not actually used
 904 * @buf: where to put the result
 905 * @count: maximum to send along
 906 * @ppos: where to start
 907 *
 908 * Returns number of bytes read or error code, as appropriate
 909 */
 910static ssize_t smk_read_nltype(struct file *filp, char __user *buf,
 911                               size_t count, loff_t *ppos)
 912{
 913        char bound[40];
 914        ssize_t rc;
 915        int i;
 916
 917        if (count < SMK_LABELLEN)
 918                return -EINVAL;
 919
 920        if (*ppos != 0)
 921                return 0;
 922
 923        sprintf(bound, "unknown");
 924
 925        for (i = 0; i < ARRAY_SIZE(netlbl_choices); i++)
 926                if (smack_net_nltype == netlbl_choices[i].o_number) {
 927                        sprintf(bound, "%s", netlbl_choices[i].o_name);
 928                        break;
 929                }
 930
 931        rc = simple_read_from_buffer(buf, count, ppos, bound, strlen(bound));
 932
 933        return rc;
 934}
 935
 936/**
 937 * smk_write_nltype - write() for /smack/nltype
 938 * @filp: file pointer, not actually used
 939 * @buf: where to get the data from
 940 * @count: bytes sent
 941 * @ppos: where to start
 942 *
 943 * Returns number of bytes written or error code, as appropriate
 944 */
 945static ssize_t smk_write_nltype(struct file *file, const char __user *buf,
 946                                size_t count, loff_t *ppos)
 947{
 948        char bound[40];
 949        char *cp;
 950        int i;
 951
 952        if (!capable(CAP_MAC_ADMIN))
 953                return -EPERM;
 954
 955        if (count >= 40)
 956                return -EINVAL;
 957
 958        if (copy_from_user(bound, buf, count) != 0)
 959                return -EFAULT;
 960
 961        bound[count] = '\0';
 962        cp = strchr(bound, ' ');
 963        if (cp != NULL)
 964                *cp = '\0';
 965        cp = strchr(bound, '\n');
 966        if (cp != NULL)
 967                *cp = '\0';
 968
 969        for (i = 0; i < ARRAY_SIZE(netlbl_choices); i++)
 970                if (strcmp(bound, netlbl_choices[i].o_name) == 0 ||
 971                    strcmp(bound, netlbl_choices[i].o_alias) == 0) {
 972                        smack_net_nltype = netlbl_choices[i].o_number;
 973                        return count;
 974                }
 975        /*
 976         * Not a valid choice.
 977         */
 978        return -EINVAL;
 979}
 980
 981static const struct file_operations smk_nltype_ops = {
 982        .read           = smk_read_nltype,
 983        .write          = smk_write_nltype,
 984};
 985
 986/**
 987 * smk_fill_super - fill the /smackfs superblock
 988 * @sb: the empty superblock
 989 * @data: unused
 990 * @silent: unused
 991 *
 992 * Fill in the well known entries for /smack
 993 *
 994 * Returns 0 on success, an error code on failure
 995 */
 996static int smk_fill_super(struct super_block *sb, void *data, int silent)
 997{
 998        int rc;
 999        struct inode *root_inode;
1000
1001        static struct tree_descr smack_files[] = {
1002                [SMK_LOAD]      =
1003                        {"load", &smk_load_ops, S_IRUGO|S_IWUSR},
1004                [SMK_CIPSO]     =
1005                        {"cipso", &smk_cipso_ops, S_IRUGO|S_IWUSR},
1006                [SMK_DOI]       =
1007                        {"doi", &smk_doi_ops, S_IRUGO|S_IWUSR},
1008                [SMK_DIRECT]    =
1009                        {"direct", &smk_direct_ops, S_IRUGO|S_IWUSR},
1010                [SMK_AMBIENT]   =
1011                        {"ambient", &smk_ambient_ops, S_IRUGO|S_IWUSR},
1012                [SMK_NLTYPE]    =
1013                        {"nltype", &smk_nltype_ops, S_IRUGO|S_IWUSR},
1014                [SMK_ONLYCAP]   =
1015                        {"onlycap", &smk_onlycap_ops, S_IRUGO|S_IWUSR},
1016                /* last one */ {""}
1017        };
1018
1019        rc = simple_fill_super(sb, SMACK_MAGIC, smack_files);
1020        if (rc != 0) {
1021                printk(KERN_ERR "%s failed %d while creating inodes\n",
1022                        __func__, rc);
1023                return rc;
1024        }
1025
1026        root_inode = sb->s_root->d_inode;
1027        root_inode->i_security = new_inode_smack(smack_known_floor.smk_known);
1028
1029        return 0;
1030}
1031
1032/**
1033 * smk_get_sb - get the smackfs superblock
1034 * @fs_type: passed along without comment
1035 * @flags: passed along without comment
1036 * @dev_name: passed along without comment
1037 * @data: passed along without comment
1038 * @mnt: passed along without comment
1039 *
1040 * Just passes everything along.
1041 *
1042 * Returns what the lower level code does.
1043 */
1044static int smk_get_sb(struct file_system_type *fs_type,
1045                      int flags, const char *dev_name, void *data,
1046                      struct vfsmount *mnt)
1047{
1048        return get_sb_single(fs_type, flags, data, smk_fill_super, mnt);
1049}
1050
1051static struct file_system_type smk_fs_type = {
1052        .name           = "smackfs",
1053        .get_sb         = smk_get_sb,
1054        .kill_sb        = kill_litter_super,
1055};
1056
1057static struct vfsmount *smackfs_mount;
1058
1059/**
1060 * init_smk_fs - get the smackfs superblock
1061 *
1062 * register the smackfs
1063 *
1064 * Do not register smackfs if Smack wasn't enabled
1065 * on boot. We can not put this method normally under the
1066 * smack_init() code path since the security subsystem get
1067 * initialized before the vfs caches.
1068 *
1069 * Returns true if we were not chosen on boot or if
1070 * we were chosen and filesystem registration succeeded.
1071 */
1072static int __init init_smk_fs(void)
1073{
1074        int err;
1075
1076        if (!security_module_enable(&smack_ops))
1077                return 0;
1078
1079        err = register_filesystem(&smk_fs_type);
1080        if (!err) {
1081                smackfs_mount = kern_mount(&smk_fs_type);
1082                if (IS_ERR(smackfs_mount)) {
1083                        printk(KERN_ERR "smackfs:  could not mount!\n");
1084                        err = PTR_ERR(smackfs_mount);
1085                        smackfs_mount = NULL;
1086                }
1087        }
1088
1089        smk_cipso_doi();
1090        smk_unlbl_ambient(NULL);
1091
1092        return err;
1093}
1094
1095__initcall(init_smk_fs);
1096