linux/fs/f2fs/acl.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * fs/f2fs/acl.c
   4 *
   5 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   6 *             http://www.samsung.com/
   7 *
   8 * Portions of this code from linux/fs/ext2/acl.c
   9 *
  10 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
  11 */
  12#include <linux/f2fs_fs.h>
  13#include "f2fs.h"
  14#include "xattr.h"
  15#include "acl.h"
  16
  17static inline size_t f2fs_acl_size(int count)
  18{
  19        if (count <= 4) {
  20                return sizeof(struct f2fs_acl_header) +
  21                        count * sizeof(struct f2fs_acl_entry_short);
  22        } else {
  23                return sizeof(struct f2fs_acl_header) +
  24                        4 * sizeof(struct f2fs_acl_entry_short) +
  25                        (count - 4) * sizeof(struct f2fs_acl_entry);
  26        }
  27}
  28
  29static inline int f2fs_acl_count(size_t size)
  30{
  31        ssize_t s;
  32
  33        size -= sizeof(struct f2fs_acl_header);
  34        s = size - 4 * sizeof(struct f2fs_acl_entry_short);
  35        if (s < 0) {
  36                if (size % sizeof(struct f2fs_acl_entry_short))
  37                        return -1;
  38                return size / sizeof(struct f2fs_acl_entry_short);
  39        } else {
  40                if (s % sizeof(struct f2fs_acl_entry))
  41                        return -1;
  42                return s / sizeof(struct f2fs_acl_entry) + 4;
  43        }
  44}
  45
  46static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
  47{
  48        int i, count;
  49        struct posix_acl *acl;
  50        struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value;
  51        struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
  52        const char *end = value + size;
  53
  54        if (size < sizeof(struct f2fs_acl_header))
  55                return ERR_PTR(-EINVAL);
  56
  57        if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
  58                return ERR_PTR(-EINVAL);
  59
  60        count = f2fs_acl_count(size);
  61        if (count < 0)
  62                return ERR_PTR(-EINVAL);
  63        if (count == 0)
  64                return NULL;
  65
  66        acl = posix_acl_alloc(count, GFP_NOFS);
  67        if (!acl)
  68                return ERR_PTR(-ENOMEM);
  69
  70        for (i = 0; i < count; i++) {
  71
  72                if ((char *)entry > end)
  73                        goto fail;
  74
  75                acl->a_entries[i].e_tag  = le16_to_cpu(entry->e_tag);
  76                acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm);
  77
  78                switch (acl->a_entries[i].e_tag) {
  79                case ACL_USER_OBJ:
  80                case ACL_GROUP_OBJ:
  81                case ACL_MASK:
  82                case ACL_OTHER:
  83                        entry = (struct f2fs_acl_entry *)((char *)entry +
  84                                        sizeof(struct f2fs_acl_entry_short));
  85                        break;
  86
  87                case ACL_USER:
  88                        acl->a_entries[i].e_uid =
  89                                make_kuid(&init_user_ns,
  90                                                le32_to_cpu(entry->e_id));
  91                        entry = (struct f2fs_acl_entry *)((char *)entry +
  92                                        sizeof(struct f2fs_acl_entry));
  93                        break;
  94                case ACL_GROUP:
  95                        acl->a_entries[i].e_gid =
  96                                make_kgid(&init_user_ns,
  97                                                le32_to_cpu(entry->e_id));
  98                        entry = (struct f2fs_acl_entry *)((char *)entry +
  99                                        sizeof(struct f2fs_acl_entry));
 100                        break;
 101                default:
 102                        goto fail;
 103                }
 104        }
 105        if ((char *)entry != end)
 106                goto fail;
 107        return acl;
 108fail:
 109        posix_acl_release(acl);
 110        return ERR_PTR(-EINVAL);
 111}
 112
 113static void *f2fs_acl_to_disk(struct f2fs_sb_info *sbi,
 114                                const struct posix_acl *acl, size_t *size)
 115{
 116        struct f2fs_acl_header *f2fs_acl;
 117        struct f2fs_acl_entry *entry;
 118        int i;
 119
 120        f2fs_acl = f2fs_kmalloc(sbi, sizeof(struct f2fs_acl_header) +
 121                        acl->a_count * sizeof(struct f2fs_acl_entry),
 122                        GFP_NOFS);
 123        if (!f2fs_acl)
 124                return ERR_PTR(-ENOMEM);
 125
 126        f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
 127        entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
 128
 129        for (i = 0; i < acl->a_count; i++) {
 130
 131                entry->e_tag  = cpu_to_le16(acl->a_entries[i].e_tag);
 132                entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
 133
 134                switch (acl->a_entries[i].e_tag) {
 135                case ACL_USER:
 136                        entry->e_id = cpu_to_le32(
 137                                        from_kuid(&init_user_ns,
 138                                                acl->a_entries[i].e_uid));
 139                        entry = (struct f2fs_acl_entry *)((char *)entry +
 140                                        sizeof(struct f2fs_acl_entry));
 141                        break;
 142                case ACL_GROUP:
 143                        entry->e_id = cpu_to_le32(
 144                                        from_kgid(&init_user_ns,
 145                                                acl->a_entries[i].e_gid));
 146                        entry = (struct f2fs_acl_entry *)((char *)entry +
 147                                        sizeof(struct f2fs_acl_entry));
 148                        break;
 149                case ACL_USER_OBJ:
 150                case ACL_GROUP_OBJ:
 151                case ACL_MASK:
 152                case ACL_OTHER:
 153                        entry = (struct f2fs_acl_entry *)((char *)entry +
 154                                        sizeof(struct f2fs_acl_entry_short));
 155                        break;
 156                default:
 157                        goto fail;
 158                }
 159        }
 160        *size = f2fs_acl_size(acl->a_count);
 161        return (void *)f2fs_acl;
 162
 163fail:
 164        kfree(f2fs_acl);
 165        return ERR_PTR(-EINVAL);
 166}
 167
 168static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
 169                                                struct page *dpage)
 170{
 171        int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
 172        void *value = NULL;
 173        struct posix_acl *acl;
 174        int retval;
 175
 176        if (type == ACL_TYPE_ACCESS)
 177                name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 178
 179        retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage);
 180        if (retval > 0) {
 181                value = f2fs_kmalloc(F2FS_I_SB(inode), retval, GFP_F2FS_ZERO);
 182                if (!value)
 183                        return ERR_PTR(-ENOMEM);
 184                retval = f2fs_getxattr(inode, name_index, "", value,
 185                                                        retval, dpage);
 186        }
 187
 188        if (retval > 0)
 189                acl = f2fs_acl_from_disk(value, retval);
 190        else if (retval == -ENODATA)
 191                acl = NULL;
 192        else
 193                acl = ERR_PTR(retval);
 194        kfree(value);
 195
 196        return acl;
 197}
 198
 199struct posix_acl *f2fs_get_acl(struct inode *inode, int type, bool rcu)
 200{
 201        if (rcu)
 202                return ERR_PTR(-ECHILD);
 203
 204        return __f2fs_get_acl(inode, type, NULL);
 205}
 206
 207static int f2fs_acl_update_mode(struct user_namespace *mnt_userns,
 208                                struct inode *inode, umode_t *mode_p,
 209                                struct posix_acl **acl)
 210{
 211        umode_t mode = inode->i_mode;
 212        int error;
 213
 214        if (is_inode_flag_set(inode, FI_ACL_MODE))
 215                mode = F2FS_I(inode)->i_acl_mode;
 216
 217        error = posix_acl_equiv_mode(*acl, &mode);
 218        if (error < 0)
 219                return error;
 220        if (error == 0)
 221                *acl = NULL;
 222        if (!in_group_p(i_gid_into_mnt(mnt_userns, inode)) &&
 223            !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID))
 224                mode &= ~S_ISGID;
 225        *mode_p = mode;
 226        return 0;
 227}
 228
 229static int __f2fs_set_acl(struct user_namespace *mnt_userns,
 230                        struct inode *inode, int type,
 231                        struct posix_acl *acl, struct page *ipage)
 232{
 233        int name_index;
 234        void *value = NULL;
 235        size_t size = 0;
 236        int error;
 237        umode_t mode = inode->i_mode;
 238
 239        switch (type) {
 240        case ACL_TYPE_ACCESS:
 241                name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
 242                if (acl && !ipage) {
 243                        error = f2fs_acl_update_mode(mnt_userns, inode,
 244                                                                &mode, &acl);
 245                        if (error)
 246                                return error;
 247                        set_acl_inode(inode, mode);
 248                }
 249                break;
 250
 251        case ACL_TYPE_DEFAULT:
 252                name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
 253                if (!S_ISDIR(inode->i_mode))
 254                        return acl ? -EACCES : 0;
 255                break;
 256
 257        default:
 258                return -EINVAL;
 259        }
 260
 261        if (acl) {
 262                value = f2fs_acl_to_disk(F2FS_I_SB(inode), acl, &size);
 263                if (IS_ERR(value)) {
 264                        clear_inode_flag(inode, FI_ACL_MODE);
 265                        return PTR_ERR(value);
 266                }
 267        }
 268
 269        error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0);
 270
 271        kfree(value);
 272        if (!error)
 273                set_cached_acl(inode, type, acl);
 274
 275        clear_inode_flag(inode, FI_ACL_MODE);
 276        return error;
 277}
 278
 279int f2fs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
 280                 struct posix_acl *acl, int type)
 281{
 282        if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
 283                return -EIO;
 284
 285        return __f2fs_set_acl(mnt_userns, inode, type, acl, NULL);
 286}
 287
 288/*
 289 * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
 290 * are copied from posix_acl.c
 291 */
 292static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
 293                                                        gfp_t flags)
 294{
 295        struct posix_acl *clone = NULL;
 296
 297        if (acl) {
 298                int size = sizeof(struct posix_acl) + acl->a_count *
 299                                sizeof(struct posix_acl_entry);
 300                clone = kmemdup(acl, size, flags);
 301                if (clone)
 302                        refcount_set(&clone->a_refcount, 1);
 303        }
 304        return clone;
 305}
 306
 307static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
 308{
 309        struct posix_acl_entry *pa, *pe;
 310        struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
 311        umode_t mode = *mode_p;
 312        int not_equiv = 0;
 313
 314        /* assert(atomic_read(acl->a_refcount) == 1); */
 315
 316        FOREACH_ACL_ENTRY(pa, acl, pe) {
 317                switch (pa->e_tag) {
 318                case ACL_USER_OBJ:
 319                        pa->e_perm &= (mode >> 6) | ~S_IRWXO;
 320                        mode &= (pa->e_perm << 6) | ~S_IRWXU;
 321                        break;
 322
 323                case ACL_USER:
 324                case ACL_GROUP:
 325                        not_equiv = 1;
 326                        break;
 327
 328                case ACL_GROUP_OBJ:
 329                        group_obj = pa;
 330                        break;
 331
 332                case ACL_OTHER:
 333                        pa->e_perm &= mode | ~S_IRWXO;
 334                        mode &= pa->e_perm | ~S_IRWXO;
 335                        break;
 336
 337                case ACL_MASK:
 338                        mask_obj = pa;
 339                        not_equiv = 1;
 340                        break;
 341
 342                default:
 343                        return -EIO;
 344                }
 345        }
 346
 347        if (mask_obj) {
 348                mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
 349                mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
 350        } else {
 351                if (!group_obj)
 352                        return -EIO;
 353                group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
 354                mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
 355        }
 356
 357        *mode_p = (*mode_p & ~S_IRWXUGO) | mode;
 358        return not_equiv;
 359}
 360
 361static int f2fs_acl_create(struct inode *dir, umode_t *mode,
 362                struct posix_acl **default_acl, struct posix_acl **acl,
 363                struct page *dpage)
 364{
 365        struct posix_acl *p;
 366        struct posix_acl *clone;
 367        int ret;
 368
 369        *acl = NULL;
 370        *default_acl = NULL;
 371
 372        if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
 373                return 0;
 374
 375        p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
 376        if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
 377                *mode &= ~current_umask();
 378                return 0;
 379        }
 380        if (IS_ERR(p))
 381                return PTR_ERR(p);
 382
 383        clone = f2fs_acl_clone(p, GFP_NOFS);
 384        if (!clone) {
 385                ret = -ENOMEM;
 386                goto release_acl;
 387        }
 388
 389        ret = f2fs_acl_create_masq(clone, mode);
 390        if (ret < 0)
 391                goto release_clone;
 392
 393        if (ret == 0)
 394                posix_acl_release(clone);
 395        else
 396                *acl = clone;
 397
 398        if (!S_ISDIR(*mode))
 399                posix_acl_release(p);
 400        else
 401                *default_acl = p;
 402
 403        return 0;
 404
 405release_clone:
 406        posix_acl_release(clone);
 407release_acl:
 408        posix_acl_release(p);
 409        return ret;
 410}
 411
 412int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
 413                                                        struct page *dpage)
 414{
 415        struct posix_acl *default_acl = NULL, *acl = NULL;
 416        int error;
 417
 418        error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
 419        if (error)
 420                return error;
 421
 422        f2fs_mark_inode_dirty_sync(inode, true);
 423
 424        if (default_acl) {
 425                error = __f2fs_set_acl(NULL, inode, ACL_TYPE_DEFAULT, default_acl,
 426                                       ipage);
 427                posix_acl_release(default_acl);
 428        } else {
 429                inode->i_default_acl = NULL;
 430        }
 431        if (acl) {
 432                if (!error)
 433                        error = __f2fs_set_acl(NULL, inode, ACL_TYPE_ACCESS, acl,
 434                                               ipage);
 435                posix_acl_release(acl);
 436        } else {
 437                inode->i_acl = NULL;
 438        }
 439
 440        return error;
 441}
 442