| 1 | /* $NetBSD: ext2fs_xattr.c,v 1.4 2016/08/23 06:40:54 christos Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2016 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Jaromir Dolecek. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 29 | * POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | #include <sys/cdefs.h> |
| 33 | __KERNEL_RCSID(0, "$NetBSD: ext2fs_xattr.c,v 1.4 2016/08/23 06:40:54 christos Exp $" ); |
| 34 | |
| 35 | #include <sys/param.h> |
| 36 | #include <sys/systm.h> |
| 37 | #include <sys/mount.h> |
| 38 | #include <sys/proc.h> |
| 39 | #include <sys/file.h> |
| 40 | #include <sys/buf.h> |
| 41 | #include <sys/vnode.h> |
| 42 | #include <sys/kernel.h> |
| 43 | #include <sys/kmem.h> |
| 44 | #include <sys/trace.h> |
| 45 | #include <sys/resourcevar.h> |
| 46 | #include <sys/kauth.h> |
| 47 | #include <sys/extattr.h> |
| 48 | |
| 49 | #include <ufs/ufs/inode.h> |
| 50 | #include <ufs/ufs/ufsmount.h> |
| 51 | #include <ufs/ufs/ufs_extern.h> |
| 52 | |
| 53 | #include <ufs/ext2fs/ext2fs.h> |
| 54 | #include <ufs/ext2fs/ext2fs_extern.h> |
| 55 | #include <ufs/ext2fs/ext2fs_xattr.h> |
| 56 | |
| 57 | static const char * const xattr_prefix_index[] = { |
| 58 | "" , |
| 59 | "user." , |
| 60 | "system.posix_acl_access" , |
| 61 | "system.posix_acl_default" , |
| 62 | "trusted." , |
| 63 | "" , /* unused */ |
| 64 | "security" , |
| 65 | "system." , |
| 66 | "system.richacl" , |
| 67 | "c" , |
| 68 | }; |
| 69 | |
| 70 | static int |
| 71 | ext2fs_find_xattr(struct ext2fs_xattr_entry *e, uint8_t *start, uint8_t *end, |
| 72 | int attrnamespace, struct uio *uio, size_t *size, uint8_t name_index, |
| 73 | const char *name) |
| 74 | { |
| 75 | uint8_t *value; |
| 76 | int error; |
| 77 | size_t value_offs, value_len, len, old_len; |
| 78 | |
| 79 | /* |
| 80 | * Individual entries follow the header. Each is aligned on 4-byte |
| 81 | * boundary. |
| 82 | */ |
| 83 | for(; !EXT2FS_XATTR_IS_LAST_ENTRY(e, end); e = EXT2FS_XATTR_NEXT(e)) { |
| 84 | /* |
| 85 | * Only EXT2FS_XATTR_PREFIX_USER is USER, anything else |
| 86 | * is considered SYSTEM. |
| 87 | */ |
| 88 | if ((attrnamespace == EXTATTR_NAMESPACE_USER |
| 89 | && e->e_name_index != EXT2FS_XATTR_PREFIX_USER) || |
| 90 | (attrnamespace == EXTATTR_NAMESPACE_SYSTEM |
| 91 | && e->e_name_index == EXT2FS_XATTR_PREFIX_USER)) { |
| 92 | continue; |
| 93 | } |
| 94 | |
| 95 | if (e->e_name_index != name_index || |
| 96 | e->e_name_len != strlen(name) || |
| 97 | strncmp(e->e_name, name, e->e_name_len) != 0) |
| 98 | continue; |
| 99 | |
| 100 | value_offs = fs2h32(e->e_value_offs); |
| 101 | value_len = fs2h32(e->e_value_size); |
| 102 | value = &start[value_offs]; |
| 103 | |
| 104 | /* make sure the value offset are sane */ |
| 105 | if (&value[value_len] > end) |
| 106 | return EINVAL; |
| 107 | |
| 108 | if (uio != NULL) { |
| 109 | /* |
| 110 | * Figure out maximum to transfer -- use buffer size |
| 111 | * and local data limit. |
| 112 | */ |
| 113 | len = MIN(uio->uio_resid, value_len); |
| 114 | old_len = uio->uio_resid; |
| 115 | uio->uio_resid = len; |
| 116 | |
| 117 | uio->uio_resid = old_len - (len - uio->uio_resid); |
| 118 | |
| 119 | error = uiomove(value, value_len, uio); |
| 120 | if (error) |
| 121 | return error; |
| 122 | } |
| 123 | |
| 124 | /* full data size */ |
| 125 | *size += value_len; |
| 126 | |
| 127 | goto found; |
| 128 | } |
| 129 | |
| 130 | /* requested attribute not found */ |
| 131 | return ENODATA; |
| 132 | |
| 133 | found: |
| 134 | return 0; |
| 135 | } |
| 136 | |
| 137 | static int |
| 138 | ext2fs_get_inode_xattr(struct inode *ip, int attrnamespace, struct uio *uio, |
| 139 | size_t *size, uint8_t name_index, const char *name) |
| 140 | { |
| 141 | struct ext2fs_dinode *di = ip->i_din.e2fs_din; |
| 142 | struct ext2fs_xattr_ibody_header *h; |
| 143 | uint8_t *start, *end; |
| 144 | |
| 145 | start = &((uint8_t *)di)[EXT2_REV0_DINODE_SIZE + di->e2di_extra_isize]; |
| 146 | h = (struct ext2fs_xattr_ibody_header *)start; |
| 147 | end = &((uint8_t *)di)[EXT2_DINODE_SIZE(ip->i_e2fs)]; |
| 148 | |
| 149 | if (end <= start || fs2h32(h->h_magic) != EXT2FS_XATTR_MAGIC) |
| 150 | return ENODATA; |
| 151 | |
| 152 | return ext2fs_find_xattr(EXT2FS_XATTR_IFIRST(h), start, end, |
| 153 | attrnamespace, uio, size, name_index, name); |
| 154 | } |
| 155 | |
| 156 | static int |
| 157 | ext2fs_get_block_xattr(struct inode *ip, int attrnamespace, struct uio *uio, |
| 158 | size_t *size, uint8_t name_index, const char *name) |
| 159 | { |
| 160 | struct ext2fs_dinode *di = ip->i_din.e2fs_din; |
| 161 | uint8_t *start, *end; |
| 162 | struct ext2fs_xattr_header *h; |
| 163 | int error = 0; |
| 164 | struct buf *bp = NULL; |
| 165 | daddr_t xblk; |
| 166 | |
| 167 | xblk = di->e2di_facl; |
| 168 | if (EXT2F_HAS_INCOMPAT_FEATURE(ip->i_e2fs, EXT2F_INCOMPAT_64BIT)) |
| 169 | xblk |= (((daddr_t)di->e2di_facl_high) << 32); |
| 170 | |
| 171 | /* don't do anything if no attr block was allocated */ |
| 172 | if (xblk == 0) |
| 173 | return 0; |
| 174 | |
| 175 | error = bread(ip->i_devvp, fsbtodb(ip->i_e2fs, xblk), |
| 176 | (int)ip->i_e2fs->e2fs_bsize, 0, &bp); |
| 177 | if (error) |
| 178 | goto out; |
| 179 | |
| 180 | start = (uint8_t *)bp->b_data; |
| 181 | h = (struct ext2fs_xattr_header *)start; |
| 182 | end = &((uint8_t *)bp->b_data)[bp->b_bcount]; |
| 183 | |
| 184 | if (end <= start || fs2h32(h->h_magic) != EXT2FS_XATTR_MAGIC) |
| 185 | goto out; |
| 186 | |
| 187 | error = ext2fs_find_xattr(EXT2FS_XATTR_BFIRST(h), start, end, |
| 188 | attrnamespace, uio, size, name_index, name); |
| 189 | |
| 190 | out: |
| 191 | if (bp) |
| 192 | brelse(bp, 0); |
| 193 | return error; |
| 194 | } |
| 195 | int |
| 196 | ext2fs_getextattr(void *v) |
| 197 | { |
| 198 | struct vop_getextattr_args /* { |
| 199 | const struct vnodeop_desc *a_desc; |
| 200 | struct vnode *a_vp; |
| 201 | int a_attrnamespace; |
| 202 | const char *a_name; |
| 203 | struct uio *a_uio; |
| 204 | size_t *a_size; |
| 205 | kauth_cred_t a_cred; |
| 206 | } */ *ap = v; |
| 207 | struct inode *ip = VTOI(ap->a_vp); |
| 208 | char namebuf[EXT2FS_XATTR_NAME_LEN_MAX + 1]; |
| 209 | int error; |
| 210 | const char *prefix, *name; |
| 211 | uint8_t name_index; |
| 212 | size_t name_match, valuesize = 0; |
| 213 | |
| 214 | if (ap->a_attrnamespace == EXTATTR_NAMESPACE_USER) |
| 215 | prefix = xattr_prefix_index[EXT2FS_XATTR_PREFIX_USER]; |
| 216 | else |
| 217 | prefix = xattr_prefix_index[EXT2FS_XATTR_PREFIX_SYSTEM]; |
| 218 | snprintf(namebuf, sizeof(namebuf), "%s%s" , prefix, ap->a_name); |
| 219 | |
| 220 | error = extattr_check_cred(ap->a_vp, namebuf, ap->a_cred, VREAD); |
| 221 | if (error) |
| 222 | return error; |
| 223 | |
| 224 | /* |
| 225 | * Allow only offsets of zero to encourage the read/replace |
| 226 | * extended attribute semantic. Otherwise we can't guarantee |
| 227 | * atomicity, as we don't provide locks for extended attributes. |
| 228 | */ |
| 229 | if (ap->a_uio != NULL && ap->a_uio->uio_offset != 0) |
| 230 | return ENXIO; |
| 231 | |
| 232 | /* figure out the name index */ |
| 233 | name = ap->a_name; |
| 234 | name_index = 0; |
| 235 | name_match = 0; |
| 236 | for(size_t i = 0; i < __arraycount(xattr_prefix_index); i++) { |
| 237 | prefix = xattr_prefix_index[i]; |
| 238 | size_t l = strlen(prefix); |
| 239 | if (l > 0 && strncmp(ap->a_name, prefix, l) == 0 && |
| 240 | name_match < l) { |
| 241 | name = &ap->a_name[l]; |
| 242 | name_index = i; |
| 243 | name_match = l; |
| 244 | continue; |
| 245 | } |
| 246 | } |
| 247 | |
| 248 | /* fetch the xattr */ |
| 249 | error = ext2fs_get_inode_xattr(ip, ap->a_attrnamespace, ap->a_uio, |
| 250 | &valuesize, name_index, name); |
| 251 | if (error == ENODATA) { |
| 252 | /* not found in inode, try facl */ |
| 253 | error = ext2fs_get_block_xattr(ip, ap->a_attrnamespace, |
| 254 | ap->a_uio, &valuesize, name_index, name); |
| 255 | } |
| 256 | |
| 257 | if (ap->a_size != NULL) |
| 258 | *ap->a_size = valuesize; |
| 259 | |
| 260 | return error; |
| 261 | } |
| 262 | |
| 263 | int |
| 264 | ext2fs_setextattr(void *v) |
| 265 | { |
| 266 | #if 0 |
| 267 | struct vop_setextattr_args /* { |
| 268 | const struct vnodeop_desc *a_desc; |
| 269 | struct vnode *a_vp; |
| 270 | int a_attrnamespace; |
| 271 | const char *a_name; |
| 272 | struct uio *a_uio; |
| 273 | kauth_cred_t a_cred; |
| 274 | } */ *ap = v; |
| 275 | |
| 276 | /* XXX set EXT2F_COMPAT_EXTATTR in superblock after successful set */ |
| 277 | #endif |
| 278 | |
| 279 | /* XXX Not implemented */ |
| 280 | return EOPNOTSUPP; |
| 281 | } |
| 282 | |
| 283 | static int |
| 284 | ext2fs_list_xattr(struct ext2fs_xattr_entry *e, uint8_t *end, |
| 285 | int attrnamespace, int flags, struct uio *uio, size_t *size) |
| 286 | { |
| 287 | char name[EXT2FS_XATTR_NAME_LEN_MAX + 1]; |
| 288 | uint8_t len; |
| 289 | int error; |
| 290 | const char *prefix; |
| 291 | |
| 292 | /* |
| 293 | * Individual entries follow the header. Each is aligned on 4-byte |
| 294 | * boundary. |
| 295 | */ |
| 296 | for(; !EXT2FS_XATTR_IS_LAST_ENTRY(e, end); e = EXT2FS_XATTR_NEXT(e)) { |
| 297 | /* |
| 298 | * Only EXT2FS_XATTR_PREFIX_USER is USER, anything else |
| 299 | * is considered SYSTEM. |
| 300 | */ |
| 301 | if ((attrnamespace == EXTATTR_NAMESPACE_USER |
| 302 | && e->e_name_index != EXT2FS_XATTR_PREFIX_USER) || |
| 303 | (attrnamespace == EXTATTR_NAMESPACE_SYSTEM |
| 304 | && e->e_name_index == EXT2FS_XATTR_PREFIX_USER)) { |
| 305 | continue; |
| 306 | } |
| 307 | |
| 308 | if (e->e_name_index < __arraycount(xattr_prefix_index)) |
| 309 | prefix = xattr_prefix_index[e->e_name_index]; |
| 310 | else |
| 311 | prefix = "" ; |
| 312 | |
| 313 | len = snprintf(name, sizeof(name), "%s%.*s" , |
| 314 | prefix, |
| 315 | e->e_name_len, e->e_name); |
| 316 | |
| 317 | if (uio != NULL) { |
| 318 | if (flags & EXTATTR_LIST_LENPREFIX) { |
| 319 | /* write name length */ |
| 320 | error = uiomove(&len, sizeof(uint8_t), uio); |
| 321 | if (error) |
| 322 | return error; |
| 323 | } else { |
| 324 | /* include trailing NUL */ |
| 325 | len++; |
| 326 | } |
| 327 | |
| 328 | error = uiomove(name, len, uio); |
| 329 | if (error) |
| 330 | return error; |
| 331 | |
| 332 | *size += len; |
| 333 | } |
| 334 | } |
| 335 | |
| 336 | return 0; |
| 337 | } |
| 338 | |
| 339 | static int |
| 340 | ext2fs_list_inode_xattr(struct inode *ip, int attrnamespace, int flags, |
| 341 | struct uio *uio, size_t *size) |
| 342 | { |
| 343 | struct ext2fs_dinode *di = ip->i_din.e2fs_din; |
| 344 | void *start, *end; |
| 345 | struct ext2fs_xattr_ibody_header *h; |
| 346 | |
| 347 | start = &((uint8_t *)di)[EXT2_REV0_DINODE_SIZE + di->e2di_extra_isize]; |
| 348 | h = start; |
| 349 | end = &((uint8_t *)di)[EXT2_DINODE_SIZE(ip->i_e2fs)]; |
| 350 | |
| 351 | if (end <= start || fs2h32(h->h_magic) != EXT2FS_XATTR_MAGIC) |
| 352 | return 0; |
| 353 | |
| 354 | return ext2fs_list_xattr(EXT2FS_XATTR_IFIRST(h), end, attrnamespace, |
| 355 | flags, uio, size); |
| 356 | } |
| 357 | |
| 358 | static int |
| 359 | ext2fs_list_block_xattr(struct inode *ip, int attrnamespace, int flags, |
| 360 | struct uio *uio, size_t *size) |
| 361 | { |
| 362 | struct ext2fs_dinode *di = ip->i_din.e2fs_din; |
| 363 | void *end; |
| 364 | struct ext2fs_xattr_header *h; |
| 365 | int error = 0; |
| 366 | struct buf *bp = NULL; |
| 367 | daddr_t xblk; |
| 368 | |
| 369 | xblk = di->e2di_facl; |
| 370 | if (EXT2F_HAS_INCOMPAT_FEATURE(ip->i_e2fs, EXT2F_INCOMPAT_64BIT)) |
| 371 | xblk |= (((daddr_t)di->e2di_facl_high) << 32); |
| 372 | |
| 373 | /* don't do anything if no attr block was allocated */ |
| 374 | if (xblk == 0) |
| 375 | return 0; |
| 376 | |
| 377 | error = bread(ip->i_devvp, fsbtodb(ip->i_e2fs, xblk), |
| 378 | (int)ip->i_e2fs->e2fs_bsize, 0, &bp); |
| 379 | if (error) |
| 380 | goto out; |
| 381 | |
| 382 | h = (struct ext2fs_xattr_header *)bp->b_data; |
| 383 | end = &((uint8_t *)bp->b_data)[bp->b_bcount]; |
| 384 | |
| 385 | if (end <= (void *)h || fs2h32(h->h_magic) != EXT2FS_XATTR_MAGIC) |
| 386 | goto out; |
| 387 | |
| 388 | error = ext2fs_list_xattr(EXT2FS_XATTR_BFIRST(h), end, attrnamespace, |
| 389 | flags, uio, size); |
| 390 | |
| 391 | out: |
| 392 | if (bp) |
| 393 | brelse(bp, 0); |
| 394 | return error; |
| 395 | } |
| 396 | |
| 397 | int |
| 398 | ext2fs_listextattr(void *v) |
| 399 | { |
| 400 | struct vop_listextattr_args /* { |
| 401 | const struct vnodeop_desc *a_desc; |
| 402 | struct vnode *a_vp; |
| 403 | int a_attrnamespace; |
| 404 | struct uio *a_uio; |
| 405 | size_t *a_size; |
| 406 | int a_flag; |
| 407 | kauth_cred_t a_cred; |
| 408 | } */ *ap = v; |
| 409 | struct inode *ip = VTOI(ap->a_vp); |
| 410 | int error; |
| 411 | const char *prefix; |
| 412 | size_t listsize = 0; |
| 413 | |
| 414 | if (!EXT2F_HAS_COMPAT_FEATURE(ip->i_e2fs, EXT2F_COMPAT_EXTATTR)) { |
| 415 | /* no EA on the filesystem */ |
| 416 | goto out; |
| 417 | } |
| 418 | |
| 419 | /* |
| 420 | * XXX: We can move this inside the loop and iterate on individual |
| 421 | * attributes. |
| 422 | */ |
| 423 | if (ap->a_attrnamespace == EXTATTR_NAMESPACE_USER) |
| 424 | prefix = xattr_prefix_index[EXT2FS_XATTR_PREFIX_USER]; |
| 425 | else |
| 426 | prefix = xattr_prefix_index[EXT2FS_XATTR_PREFIX_SYSTEM]; |
| 427 | error = extattr_check_cred(ap->a_vp, prefix, ap->a_cred, VREAD); |
| 428 | if (error) |
| 429 | return error; |
| 430 | |
| 431 | /* |
| 432 | * Allow only offsets of zero to encourage the read/replace |
| 433 | * extended attribute semantic. Otherwise we can't guarantee |
| 434 | * atomicity, as we don't provide locks for extended attributes. |
| 435 | * XXX revisit - vnode lock enough? |
| 436 | */ |
| 437 | if (ap->a_uio != NULL && ap->a_uio->uio_offset != 0) |
| 438 | return ENXIO; |
| 439 | |
| 440 | /* fetch inode xattrs */ |
| 441 | error = ext2fs_list_inode_xattr(ip, ap->a_attrnamespace, ap->a_flag, |
| 442 | ap->a_uio, &listsize); |
| 443 | if (error) |
| 444 | return error; |
| 445 | |
| 446 | error = ext2fs_list_block_xattr(ip, ap->a_attrnamespace, ap->a_flag, |
| 447 | ap->a_uio, &listsize); |
| 448 | if (error) |
| 449 | return error; |
| 450 | |
| 451 | out: |
| 452 | if (ap->a_size != NULL) |
| 453 | *ap->a_size = listsize; |
| 454 | |
| 455 | return 0; |
| 456 | } |
| 457 | |
| 458 | int |
| 459 | ext2fs_deleteextattr(void *v) |
| 460 | { |
| 461 | #if 0 |
| 462 | struct vop_deleteextattr_args /* { |
| 463 | const struct vnodeop_desc *a_desc; |
| 464 | struct vnode *a_vp; |
| 465 | int a_attrnamespace; |
| 466 | const char *a_name; |
| 467 | kauth_cred_t a_cred; |
| 468 | } */ *ap = v; |
| 469 | #endif |
| 470 | |
| 471 | /* XXX Not implemented */ |
| 472 | return EOPNOTSUPP; |
| 473 | } |
| 474 | |