The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/fs/ext2fs/ext2_acl.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2017, Fedor Uporov
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  *
   28  * $FreeBSD: releng/12.0/sys/fs/ext2fs/ext2_acl.c 326474 2017-12-02 17:22:55Z pfg $
   29  */
   30 
   31 #include <sys/param.h>
   32 #include <sys/systm.h>
   33 #include <sys/types.h>
   34 #include <sys/stat.h>
   35 #include <sys/kernel.h>
   36 #include <sys/malloc.h>
   37 #include <sys/vnode.h>
   38 #include <sys/bio.h>
   39 #include <sys/buf.h>
   40 #include <sys/endian.h>
   41 #include <sys/conf.h>
   42 #include <sys/mount.h>
   43 #include <sys/extattr.h>
   44 
   45 #include <fs/ext2fs/fs.h>
   46 #include <fs/ext2fs/ext2fs.h>
   47 #include <fs/ext2fs/inode.h>
   48 #include <fs/ext2fs/ext2_acl.h>
   49 #include <fs/ext2fs/ext2_extattr.h>
   50 #include <fs/ext2fs/ext2_extern.h>
   51 #include <fs/ext2fs/ext2_dinode.h>
   52 #include <fs/ext2fs/ext2_mount.h>
   53 
   54 #ifdef UFS_ACL
   55 
   56 void
   57 ext2_sync_acl_from_inode(struct inode *ip, struct acl *acl)
   58 {
   59         struct acl_entry        *acl_mask, *acl_group_obj;
   60         int     i;
   61 
   62         /*
   63          * Update ACL_USER_OBJ, ACL_OTHER, but simply identify ACL_MASK
   64          * and ACL_GROUP_OBJ for use after we know whether ACL_MASK is
   65          * present.
   66          */
   67         acl_mask = NULL;
   68         acl_group_obj = NULL;
   69         for (i = 0; i < acl->acl_cnt; i++) {
   70                 switch (acl->acl_entry[i].ae_tag) {
   71                 case ACL_USER_OBJ:
   72                         acl->acl_entry[i].ae_perm = acl_posix1e_mode_to_perm(
   73                             ACL_USER_OBJ, ip->i_mode);
   74                         acl->acl_entry[i].ae_id = ACL_UNDEFINED_ID;
   75                         break;
   76 
   77                 case ACL_GROUP_OBJ:
   78                         acl_group_obj = &acl->acl_entry[i];
   79                         acl->acl_entry[i].ae_id = ACL_UNDEFINED_ID;
   80                         break;
   81 
   82                 case ACL_OTHER:
   83                         acl->acl_entry[i].ae_perm = acl_posix1e_mode_to_perm(
   84                             ACL_OTHER, ip->i_mode);
   85                         acl->acl_entry[i].ae_id = ACL_UNDEFINED_ID;
   86                         break;
   87 
   88                 case ACL_MASK:
   89                         acl_mask = &acl->acl_entry[i];
   90                         acl->acl_entry[i].ae_id = ACL_UNDEFINED_ID;
   91                         break;
   92 
   93                 case ACL_USER:
   94                 case ACL_GROUP:
   95                         break;
   96 
   97                 default:
   98                         panic("ext2_sync_acl_from_inode(): bad ae_tag");
   99                 }
  100         }
  101 
  102         if (acl_group_obj == NULL)
  103                 panic("ext2_sync_acl_from_inode(): no ACL_GROUP_OBJ");
  104 
  105         if (acl_mask == NULL) {
  106                 /*
  107                  * There is no ACL_MASK, so update ACL_GROUP_OBJ.
  108                  */
  109                 acl_group_obj->ae_perm = acl_posix1e_mode_to_perm(
  110                     ACL_GROUP_OBJ, ip->i_mode);
  111         } else {
  112                 /*
  113                  * Update the ACL_MASK entry instead of ACL_GROUP_OBJ.
  114                  */
  115                 acl_mask->ae_perm = acl_posix1e_mode_to_perm(ACL_GROUP_OBJ,
  116                     ip->i_mode);
  117         }
  118 }
  119 
  120 static void
  121 ext2_sync_inode_from_acl(struct acl *acl, struct inode *ip)
  122 {
  123 
  124         ip->i_mode &= ACL_PRESERVE_MASK;
  125         ip->i_mode |= acl_posix1e_acl_to_mode(acl);
  126 }
  127 
  128 /*
  129  * Convert from filesystem to in-memory representation.
  130  */
  131 static int
  132 ext4_acl_from_disk(char *value, size_t size, struct acl *acl)
  133 {
  134         const char *end;
  135         int n, count, s;
  136 
  137         if (value == NULL)
  138                 return (EINVAL);
  139 
  140         end = value + size;
  141 
  142         if (((struct ext2_acl_header *)value)->a_version != EXT4_ACL_VERSION)
  143                 return (EINVAL);
  144 
  145         if (size < sizeof(struct ext2_acl_header))
  146                 return (EINVAL);
  147 
  148         s = size - sizeof(struct ext2_acl_header);
  149         s -= 4 * sizeof(struct ext2_acl_entry_short);
  150         if (s < 0)
  151                 if ((size - sizeof(struct ext2_acl_header)) %
  152                     sizeof(struct ext2_acl_entry_short))
  153                         count = -1;
  154                 else
  155                         count = (size - sizeof(struct ext2_acl_header)) /
  156                             sizeof(struct ext2_acl_entry_short);
  157         else
  158                 if (s % sizeof(struct ext2_acl_entry))
  159                         count = -1;
  160                 else
  161                         count = s / sizeof(struct ext2_acl_entry) + 4;
  162 
  163         if (count <= 0 || count > acl->acl_maxcnt)
  164                 return (EINVAL);
  165 
  166         value = value + sizeof(struct ext2_acl_header);
  167 
  168         for (n = 0; n < count; n++) {
  169                 struct ext2_acl_entry *entry = (struct ext2_acl_entry *)value;
  170                 if ((char *)value + sizeof(struct ext2_acl_entry_short) > end)
  171                         return (EINVAL);
  172 
  173                 acl->acl_entry[n].ae_tag  = entry->ae_tag;
  174                 acl->acl_entry[n].ae_perm = entry->ae_perm;
  175 
  176                 switch (acl->acl_entry[n].ae_tag) {
  177                 case ACL_USER_OBJ:
  178                 case ACL_GROUP_OBJ:
  179                 case ACL_MASK:
  180                 case ACL_OTHER:
  181                         value = (char *)value + sizeof(struct ext2_acl_entry_short);
  182                         break;
  183 
  184                 case ACL_USER:
  185                         value = (char *)value + sizeof(struct ext2_acl_entry);
  186                         if ((char *)value > end)
  187                                 return (EINVAL);
  188 
  189                         acl->acl_entry[n].ae_id = entry->ae_id;
  190                         break;
  191 
  192                 case ACL_GROUP:
  193                         value = (char *)value + sizeof(struct ext2_acl_entry);
  194                         if ((char *)value > end)
  195                                 return (EINVAL);
  196 
  197                         acl->acl_entry[n].ae_id = entry->ae_id;
  198                         break;
  199 
  200                 default:
  201                         return (EINVAL);
  202                 }
  203         }
  204 
  205         if (value != end)
  206                 return (EINVAL);
  207 
  208         acl->acl_cnt = count;
  209 
  210         return (0);
  211 }
  212 
  213 static int
  214 ext2_getacl_posix1e(struct vop_getacl_args *ap)
  215 {
  216         int attrnamespace;
  217         const char *attrname;
  218         char *value;
  219         int len;
  220         int error;
  221 
  222         switch (ap->a_type) {
  223         case ACL_TYPE_DEFAULT:
  224                 attrnamespace = POSIX1E_ACL_DEFAULT_EXTATTR_NAMESPACE;
  225                 attrname = POSIX1E_ACL_DEFAULT_EXTATTR_NAME;
  226                 break;
  227         case ACL_TYPE_ACCESS:
  228                 attrnamespace = POSIX1E_ACL_ACCESS_EXTATTR_NAMESPACE;
  229                 attrname = POSIX1E_ACL_ACCESS_EXTATTR_NAME;
  230                 break;
  231         default:
  232                 return (EINVAL);
  233         }
  234 
  235         len = sizeof(*ap->a_aclp) + sizeof(struct ext2_acl_header);
  236         value = malloc(len, M_ACL, M_WAITOK);
  237         if (!value)
  238                 return (ENOMEM);
  239 
  240         error = vn_extattr_get(ap->a_vp, IO_NODELOCKED, attrnamespace, attrname,
  241             &len, value, ap->a_td);
  242         if (error == ENOATTR) {
  243                 switch (ap->a_type) {
  244                 case ACL_TYPE_ACCESS:
  245                         ap->a_aclp->acl_cnt = 3;
  246                         ap->a_aclp->acl_entry[0].ae_tag = ACL_USER_OBJ;
  247                         ap->a_aclp->acl_entry[0].ae_id = ACL_UNDEFINED_ID;
  248                         ap->a_aclp->acl_entry[0].ae_perm = ACL_PERM_NONE;
  249                         ap->a_aclp->acl_entry[1].ae_tag = ACL_GROUP_OBJ;
  250                         ap->a_aclp->acl_entry[1].ae_id = ACL_UNDEFINED_ID;
  251                         ap->a_aclp->acl_entry[1].ae_perm = ACL_PERM_NONE;
  252                         ap->a_aclp->acl_entry[2].ae_tag = ACL_OTHER;
  253                         ap->a_aclp->acl_entry[2].ae_id = ACL_UNDEFINED_ID;
  254                         ap->a_aclp->acl_entry[2].ae_perm = ACL_PERM_NONE;
  255                         break;
  256 
  257                 case ACL_TYPE_DEFAULT:
  258                         ap->a_aclp->acl_cnt = 0;
  259                         break;
  260                 }
  261         } else if (error != 0)
  262                 goto out;
  263 
  264         if (!error) {
  265                 error = ext4_acl_from_disk(value, len, ap->a_aclp);
  266                 if (error)
  267                         goto out;
  268         }
  269 
  270         if (error == ENOATTR)
  271                 error = 0;
  272 
  273         if (ap->a_type == ACL_TYPE_ACCESS)
  274                 ext2_sync_acl_from_inode(VTOI(ap->a_vp), ap->a_aclp);
  275 
  276 out:
  277         free(value, M_TEMP);
  278         return (error);
  279 }
  280 
  281 int
  282 ext2_getacl(struct vop_getacl_args *ap)
  283 {
  284 
  285         if (((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0) ||
  286             ((ap->a_vp->v_mount->mnt_flag & MNT_NFS4ACLS) != 0))
  287                 return (EOPNOTSUPP);
  288 
  289         if (ap->a_type == ACL_TYPE_NFS4)
  290                 return (ENOTSUP);
  291 
  292         return (ext2_getacl_posix1e(ap));
  293 }
  294 
  295 /*
  296  * Convert from in-memory to filesystem representation.
  297  */
  298 static int
  299 ext4_acl_to_disk(const struct acl *acl, size_t *size, char *value)
  300 {
  301         struct ext2_acl_header *ext_acl;
  302         int disk_size;
  303         char *e;
  304         size_t n;
  305 
  306         if (acl->acl_cnt <= 4)
  307                 disk_size = sizeof(struct ext2_acl_header) +
  308                    acl->acl_cnt * sizeof(struct ext2_acl_entry_short);
  309         else
  310                 disk_size = sizeof(struct ext2_acl_header) +
  311                     4 * sizeof(struct ext2_acl_entry_short) +
  312                     (acl->acl_cnt - 4) * sizeof(struct ext2_acl_entry);
  313 
  314         if (disk_size > *size)
  315                 return (EINVAL);
  316 
  317         *size = disk_size;
  318         ext_acl = (struct ext2_acl_header *)value;
  319 
  320         ext_acl->a_version = EXT4_ACL_VERSION;
  321         e = (char *)ext_acl + sizeof(struct ext2_acl_header);
  322         for (n = 0; n < acl->acl_cnt; n++) {
  323                 const struct acl_entry *acl_e = &acl->acl_entry[n];
  324                 struct ext2_acl_entry *entry = (struct ext2_acl_entry *)e;
  325                 entry->ae_tag  = acl_e->ae_tag;
  326                 entry->ae_perm = acl_e->ae_perm;
  327                 switch (acl_e->ae_tag) {
  328                 case ACL_USER:
  329                         entry->ae_id = acl_e->ae_id;
  330                         e += sizeof(struct ext2_acl_entry);
  331                         break;
  332 
  333                 case ACL_GROUP:
  334                         entry->ae_id = acl_e->ae_id;
  335                         e += sizeof(struct ext2_acl_entry);
  336                         break;
  337 
  338                 case ACL_USER_OBJ:
  339                 case ACL_GROUP_OBJ:
  340                 case ACL_MASK:
  341                 case ACL_OTHER:
  342                         e += sizeof(struct ext2_acl_entry_short);
  343                         break;
  344 
  345                 default:
  346                         return (EINVAL);
  347                 }
  348         }
  349 
  350         return (0);
  351 }
  352 
  353 static int
  354 ext2_setacl_posix1e(struct vop_setacl_args *ap)
  355 {
  356         struct inode *ip = VTOI(ap->a_vp);
  357         char *value;
  358         size_t len;
  359         int error;
  360 
  361         if ((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0)
  362                 return (EINVAL);
  363 
  364         /*
  365          * If this is a set operation rather than a delete operation,
  366          * invoke VOP_ACLCHECK() on the passed ACL to determine if it is
  367          * valid for the target.  This will include a check on ap->a_type.
  368          */
  369         if (ap->a_aclp != NULL) {
  370                 /*
  371                  * Set operation.
  372                  */
  373                 error = VOP_ACLCHECK(ap->a_vp, ap->a_type, ap->a_aclp,
  374                     ap->a_cred, ap->a_td);
  375                 if (error)
  376                         return (error);
  377         } else {
  378                 /*
  379                  * Delete operation.
  380                  * POSIX.1e allows only deletion of the default ACL on a
  381                  * directory (ACL_TYPE_DEFAULT).
  382                  */
  383                 if (ap->a_type != ACL_TYPE_DEFAULT)
  384                         return (EINVAL);
  385                 if (ap->a_vp->v_type != VDIR)
  386                         return (ENOTDIR);
  387         }
  388 
  389         if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
  390                 return (EROFS);
  391 
  392         /*
  393          * Authorize the ACL operation.
  394          */
  395         if (ip->i_flags & (IMMUTABLE | APPEND))
  396                 return (EPERM);
  397 
  398         /*
  399          * Must hold VADMIN (be file owner) or have appropriate privilege.
  400          */
  401         if ((error = VOP_ACCESS(ap->a_vp, VADMIN, ap->a_cred, ap->a_td)))
  402                 return (error);
  403 
  404         switch (ap->a_type) {
  405         case ACL_TYPE_ACCESS:
  406                 len = sizeof(*ap->a_aclp) + sizeof(struct ext2_acl_header);
  407                 value = malloc(len, M_ACL, M_WAITOK | M_ZERO);
  408                 error = ext4_acl_to_disk(ap->a_aclp, &len, value);
  409                 if (error == 0)
  410                         error = vn_extattr_set(ap->a_vp, IO_NODELOCKED,
  411                             POSIX1E_ACL_ACCESS_EXTATTR_NAMESPACE,
  412                             POSIX1E_ACL_ACCESS_EXTATTR_NAME, len,
  413                             value, ap->a_td);
  414 
  415                 free(value, M_ACL);
  416                 break;
  417 
  418         case ACL_TYPE_DEFAULT:
  419                 if (ap->a_aclp == NULL) {
  420                         error = vn_extattr_rm(ap->a_vp, IO_NODELOCKED,
  421                             POSIX1E_ACL_DEFAULT_EXTATTR_NAMESPACE,
  422                             POSIX1E_ACL_DEFAULT_EXTATTR_NAME, ap->a_td);
  423 
  424                         /*
  425                          * Attempting to delete a non-present default ACL
  426                          * will return success for portability purposes.
  427                          * (TRIX)
  428                          *
  429                          * XXX: Note that since we can't distinguish
  430                          * "that EA is not supported" from "that EA is not
  431                          * defined", the success case here overlaps the
  432                          * the ENOATTR->EOPNOTSUPP case below.
  433                          */
  434                         if (error == ENOATTR)
  435                                 error = 0;
  436                 } else {
  437                         len = sizeof(*ap->a_aclp) + sizeof(struct ext2_acl_header);
  438                         value = malloc(len, M_ACL, M_WAITOK | M_ZERO);
  439                         error = ext4_acl_to_disk(ap->a_aclp, &len, value);
  440                         if (error == 0)
  441                                 error = vn_extattr_set(ap->a_vp, IO_NODELOCKED,
  442                                     POSIX1E_ACL_DEFAULT_EXTATTR_NAMESPACE,
  443                                     POSIX1E_ACL_DEFAULT_EXTATTR_NAME, len,
  444                                     value, ap->a_td);
  445 
  446                         free(value, M_ACL);
  447                 }
  448                 break;
  449 
  450         default:
  451                 error = EINVAL;
  452         }
  453 
  454         /*
  455          * Map lack of attribute definition in UFS_EXTATTR into lack of
  456          * support for ACLs on the filesystem.
  457          */
  458         if (error == ENOATTR)
  459                 return (EOPNOTSUPP);
  460 
  461         if (error != 0)
  462                 return (error);
  463 
  464         if (ap->a_type == ACL_TYPE_ACCESS) {
  465                 /*
  466                  * Now that the EA is successfully updated, update the
  467                  * inode and mark it as changed.
  468                  */
  469                 ext2_sync_inode_from_acl(ap->a_aclp, ip);
  470                 ip->i_flag |= IN_CHANGE;
  471                 error = ext2_update(ip->i_vnode, 1);
  472         }
  473 
  474         VN_KNOTE_UNLOCKED(ap->a_vp, NOTE_ATTRIB);
  475 
  476         return (error);
  477 }
  478 
  479 int
  480 ext2_setacl(struct vop_setacl_args *ap)
  481 {
  482         if (((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0) ||
  483             ((ap->a_vp->v_mount->mnt_flag & MNT_NFS4ACLS) != 0))
  484                 return (EOPNOTSUPP);
  485 
  486         if (ap->a_type == ACL_TYPE_NFS4)
  487                 return (ENOTSUP);
  488 
  489         return (ext2_setacl_posix1e(ap));
  490 }
  491 
  492 /*
  493  * Check the validity of an ACL for a file.
  494  */
  495 int
  496 ext2_aclcheck(struct vop_aclcheck_args *ap)
  497 {
  498 
  499         if (((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0) ||
  500             ((ap->a_vp->v_mount->mnt_flag & MNT_NFS4ACLS) != 0))
  501                 return (EOPNOTSUPP);
  502 
  503         if (ap->a_type == ACL_TYPE_NFS4)
  504                 return (ENOTSUP);
  505 
  506         if ((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0)
  507                 return (EINVAL);
  508 
  509         /*
  510          * Verify we understand this type of ACL, and that it applies
  511          * to this kind of object.
  512          * Rely on the acl_posix1e_check() routine to verify the contents.
  513          */
  514         switch (ap->a_type) {
  515                 case ACL_TYPE_ACCESS:
  516                 break;
  517 
  518                 case ACL_TYPE_DEFAULT:
  519                         if (ap->a_vp->v_type != VDIR)
  520                                 return (EINVAL);
  521                 break;
  522 
  523                 default:
  524                         return (EINVAL);
  525         }
  526 
  527         return (acl_posix1e_check(ap->a_aclp));
  528 }
  529 
  530 #endif /* UFS_ACL */

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