1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2000-2006 Silicon Graphics, Inc. 4 * Copyright (c) 2012-2013 Red Hat, Inc. 5 * All rights reserved. 6 */ 7 #include "xfs.h" 8 #include "xfs_fs.h" 9 #include "xfs_format.h" 10 #include "xfs_log_format.h" 11 #include "xfs_shared.h" 12 #include "xfs_trans_resv.h" 13 #include "xfs_mount.h" 14 #include "xfs_inode.h" 15 #include "xfs_error.h" 16 #include "xfs_trans.h" 17 #include "xfs_buf_item.h" 18 #include "xfs_log.h" 19 #include "xfs_symlink_remote.h" 20 #include "xfs_bit.h" 21 #include "xfs_bmap.h" 22 #include "xfs_health.h" 23 24 /* 25 * Each contiguous block has a header, so it is not just a simple pathlen 26 * to FSB conversion. 27 */ 28 int 29 xfs_symlink_blocks( 30 struct xfs_mount *mp, 31 int pathlen) 32 { 33 int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize); 34 35 return (pathlen + buflen - 1) / buflen; 36 } 37 38 int 39 xfs_symlink_hdr_set( 40 struct xfs_mount *mp, 41 xfs_ino_t ino, 42 uint32_t offset, 43 uint32_t size, 44 struct xfs_buf *bp) 45 { 46 struct xfs_dsymlink_hdr *dsl = bp->b_addr; 47 48 if (!xfs_has_crc(mp)) 49 return 0; 50 51 memset(dsl, 0, sizeof(struct xfs_dsymlink_hdr)); 52 dsl->sl_magic = cpu_to_be32(XFS_SYMLINK_MAGIC); 53 dsl->sl_offset = cpu_to_be32(offset); 54 dsl->sl_bytes = cpu_to_be32(size); 55 uuid_copy(&dsl->sl_uuid, &mp->m_sb.sb_meta_uuid); 56 dsl->sl_owner = cpu_to_be64(ino); 57 dsl->sl_blkno = cpu_to_be64(xfs_buf_daddr(bp)); 58 bp->b_ops = &xfs_symlink_buf_ops; 59 60 return sizeof(struct xfs_dsymlink_hdr); 61 } 62 63 /* 64 * Checking of the symlink header is split into two parts. the verifier does 65 * CRC, location and bounds checking, the unpacking function checks the path 66 * parameters and owner. 67 */ 68 bool 69 xfs_symlink_hdr_ok( 70 xfs_ino_t ino, 71 uint32_t offset, 72 uint32_t size, 73 struct xfs_buf *bp) 74 { 75 struct xfs_dsymlink_hdr *dsl = bp->b_addr; 76 77 if (offset != be32_to_cpu(dsl->sl_offset)) 78 return false; 79 if (size != be32_to_cpu(dsl->sl_bytes)) 80 return false; 81 if (ino != be64_to_cpu(dsl->sl_owner)) 82 return false; 83 84 /* ok */ 85 return true; 86 } 87 88 static xfs_failaddr_t 89 xfs_symlink_verify( 90 struct xfs_buf *bp) 91 { 92 struct xfs_mount *mp = bp->b_mount; 93 struct xfs_dsymlink_hdr *dsl = bp->b_addr; 94 95 if (!xfs_has_crc(mp)) 96 return __this_address; 97 if (!xfs_verify_magic(bp, dsl->sl_magic)) 98 return __this_address; 99 if (!uuid_equal(&dsl->sl_uuid, &mp->m_sb.sb_meta_uuid)) 100 return __this_address; 101 if (xfs_buf_daddr(bp) != be64_to_cpu(dsl->sl_blkno)) 102 return __this_address; 103 if (be32_to_cpu(dsl->sl_offset) + 104 be32_to_cpu(dsl->sl_bytes) >= XFS_SYMLINK_MAXLEN) 105 return __this_address; 106 if (dsl->sl_owner == 0) 107 return __this_address; 108 if (!xfs_log_check_lsn(mp, be64_to_cpu(dsl->sl_lsn))) 109 return __this_address; 110 111 return NULL; 112 } 113 114 static void 115 xfs_symlink_read_verify( 116 struct xfs_buf *bp) 117 { 118 struct xfs_mount *mp = bp->b_mount; 119 xfs_failaddr_t fa; 120 121 /* no verification of non-crc buffers */ 122 if (!xfs_has_crc(mp)) 123 return; 124 125 if (!xfs_buf_verify_cksum(bp, XFS_SYMLINK_CRC_OFF)) 126 xfs_verifier_error(bp, -EFSBADCRC, __this_address); 127 else { 128 fa = xfs_symlink_verify(bp); 129 if (fa) 130 xfs_verifier_error(bp, -EFSCORRUPTED, fa); 131 } 132 } 133 134 static void 135 xfs_symlink_write_verify( 136 struct xfs_buf *bp) 137 { 138 struct xfs_mount *mp = bp->b_mount; 139 struct xfs_buf_log_item *bip = bp->b_log_item; 140 xfs_failaddr_t fa; 141 142 /* no verification of non-crc buffers */ 143 if (!xfs_has_crc(mp)) 144 return; 145 146 fa = xfs_symlink_verify(bp); 147 if (fa) { 148 xfs_verifier_error(bp, -EFSCORRUPTED, fa); 149 return; 150 } 151 152 if (bip) { 153 struct xfs_dsymlink_hdr *dsl = bp->b_addr; 154 dsl->sl_lsn = cpu_to_be64(bip->bli_item.li_lsn); 155 } 156 xfs_buf_update_cksum(bp, XFS_SYMLINK_CRC_OFF); 157 } 158 159 const struct xfs_buf_ops xfs_symlink_buf_ops = { 160 .name = "xfs_symlink", 161 .magic = { 0, cpu_to_be32(XFS_SYMLINK_MAGIC) }, 162 .verify_read = xfs_symlink_read_verify, 163 .verify_write = xfs_symlink_write_verify, 164 .verify_struct = xfs_symlink_verify, 165 }; 166 167 void 168 xfs_symlink_local_to_remote( 169 struct xfs_trans *tp, 170 struct xfs_buf *bp, 171 struct xfs_inode *ip, 172 struct xfs_ifork *ifp, 173 void *priv) 174 { 175 struct xfs_mount *mp = ip->i_mount; 176 char *buf; 177 178 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); 179 180 if (!xfs_has_crc(mp)) { 181 bp->b_ops = NULL; 182 memcpy(bp->b_addr, ifp->if_data, ifp->if_bytes); 183 xfs_trans_log_buf(tp, bp, 0, ifp->if_bytes - 1); 184 return; 185 } 186 187 /* 188 * As this symlink fits in an inode literal area, it must also fit in 189 * the smallest buffer the filesystem supports. 190 */ 191 ASSERT(BBTOB(bp->b_length) >= 192 ifp->if_bytes + sizeof(struct xfs_dsymlink_hdr)); 193 194 bp->b_ops = &xfs_symlink_buf_ops; 195 196 buf = bp->b_addr; 197 buf += xfs_symlink_hdr_set(mp, ip->i_ino, 0, ifp->if_bytes, bp); 198 memcpy(buf, ifp->if_data, ifp->if_bytes); 199 xfs_trans_log_buf(tp, bp, 0, sizeof(struct xfs_dsymlink_hdr) + 200 ifp->if_bytes - 1); 201 } 202 203 /* 204 * Verify the in-memory consistency of an inline symlink data fork. This 205 * does not do on-disk format checks. 206 */ 207 xfs_failaddr_t 208 xfs_symlink_shortform_verify( 209 void *sfp, 210 int64_t size) 211 { 212 char *endp = sfp + size; 213 214 /* 215 * Zero length symlinks should never occur in memory as they are 216 * never allowed to exist on disk. 217 */ 218 if (!size) 219 return __this_address; 220 221 /* No negative sizes or overly long symlink targets. */ 222 if (size < 0 || size > XFS_SYMLINK_MAXLEN) 223 return __this_address; 224 225 /* No NULLs in the target either. */ 226 if (memchr(sfp, 0, size - 1)) 227 return __this_address; 228 229 /* We /did/ null-terminate the buffer, right? */ 230 if (*endp != 0) 231 return __this_address; 232 return NULL; 233 } 234 235 /* Read a remote symlink target into the buffer. */ 236 int 237 xfs_symlink_remote_read( 238 struct xfs_inode *ip, 239 char *link) 240 { 241 struct xfs_mount *mp = ip->i_mount; 242 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 243 struct xfs_buf *bp; 244 xfs_daddr_t d; 245 char *cur_chunk; 246 int pathlen = ip->i_disk_size; 247 int nmaps = XFS_SYMLINK_MAPS; 248 int byte_cnt; 249 int n; 250 int error = 0; 251 int fsblocks = 0; 252 int offset; 253 254 xfs_assert_ilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL); 255 256 fsblocks = xfs_symlink_blocks(mp, pathlen); 257 error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0); 258 if (error) 259 goto out; 260 261 offset = 0; 262 for (n = 0; n < nmaps; n++) { 263 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 264 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 265 266 error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0, 267 &bp, &xfs_symlink_buf_ops); 268 if (xfs_metadata_is_sick(error)) 269 xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK); 270 if (error) 271 return error; 272 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 273 if (pathlen < byte_cnt) 274 byte_cnt = pathlen; 275 276 cur_chunk = bp->b_addr; 277 if (xfs_has_crc(mp)) { 278 if (!xfs_symlink_hdr_ok(ip->i_ino, offset, 279 byte_cnt, bp)) { 280 xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK); 281 error = -EFSCORRUPTED; 282 xfs_alert(mp, 283 "symlink header does not match required off/len/owner (0x%x/0x%x,0x%llx)", 284 offset, byte_cnt, ip->i_ino); 285 xfs_buf_relse(bp); 286 goto out; 287 288 } 289 290 cur_chunk += sizeof(struct xfs_dsymlink_hdr); 291 } 292 293 memcpy(link + offset, cur_chunk, byte_cnt); 294 295 pathlen -= byte_cnt; 296 offset += byte_cnt; 297 298 xfs_buf_relse(bp); 299 } 300 ASSERT(pathlen == 0); 301 302 link[ip->i_disk_size] = '\0'; 303 error = 0; 304 305 out: 306 return error; 307 } 308 309 /* Write the symlink target into the inode. */ 310 int 311 xfs_symlink_write_target( 312 struct xfs_trans *tp, 313 struct xfs_inode *ip, 314 xfs_ino_t owner, 315 const char *target_path, 316 int pathlen, 317 xfs_fsblock_t fs_blocks, 318 uint resblks) 319 { 320 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 321 struct xfs_mount *mp = tp->t_mountp; 322 const char *cur_chunk; 323 struct xfs_buf *bp; 324 xfs_daddr_t d; 325 int byte_cnt; 326 int nmaps; 327 int offset = 0; 328 int n; 329 int error; 330 331 /* 332 * If the symlink will fit into the inode, write it inline. 333 */ 334 if (pathlen <= xfs_inode_data_fork_size(ip)) { 335 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen); 336 337 ip->i_disk_size = pathlen; 338 ip->i_df.if_format = XFS_DINODE_FMT_LOCAL; 339 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE); 340 return 0; 341 } 342 343 nmaps = XFS_SYMLINK_MAPS; 344 error = xfs_bmapi_write(tp, ip, 0, fs_blocks, XFS_BMAPI_METADATA, 345 resblks, mval, &nmaps); 346 if (error) 347 return error; 348 349 ip->i_disk_size = pathlen; 350 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 351 352 cur_chunk = target_path; 353 offset = 0; 354 for (n = 0; n < nmaps; n++) { 355 char *buf; 356 357 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock); 358 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount); 359 error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, 360 BTOBB(byte_cnt), 0, &bp); 361 if (error) 362 return error; 363 bp->b_ops = &xfs_symlink_buf_ops; 364 365 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt); 366 byte_cnt = min(byte_cnt, pathlen); 367 368 buf = bp->b_addr; 369 buf += xfs_symlink_hdr_set(mp, owner, offset, byte_cnt, bp); 370 371 memcpy(buf, cur_chunk, byte_cnt); 372 373 cur_chunk += byte_cnt; 374 pathlen -= byte_cnt; 375 offset += byte_cnt; 376 377 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF); 378 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) - 379 (char *)bp->b_addr); 380 } 381 ASSERT(pathlen == 0); 382 return 0; 383 } 384 385 /* Remove all the blocks from a symlink and invalidate buffers. */ 386 int 387 xfs_symlink_remote_truncate( 388 struct xfs_trans *tp, 389 struct xfs_inode *ip) 390 { 391 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS]; 392 struct xfs_mount *mp = tp->t_mountp; 393 struct xfs_buf *bp; 394 int nmaps = XFS_SYMLINK_MAPS; 395 int done = 0; 396 int i; 397 int error; 398 399 /* Read mappings and invalidate buffers. */ 400 error = xfs_bmapi_read(ip, 0, XFS_MAX_FILEOFF, mval, &nmaps, 0); 401 if (error) 402 return error; 403 404 for (i = 0; i < nmaps; i++) { 405 if (!xfs_bmap_is_real_extent(&mval[i])) 406 break; 407 408 error = xfs_trans_get_buf(tp, mp->m_ddev_targp, 409 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock), 410 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0, 411 &bp); 412 if (error) 413 return error; 414 415 xfs_trans_binval(tp, bp); 416 } 417 418 /* Unmap the remote blocks. */ 419 error = xfs_bunmapi(tp, ip, 0, XFS_MAX_FILEOFF, 0, nmaps, &done); 420 if (error) 421 return error; 422 if (!done) { 423 ASSERT(done); 424 xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK); 425 return -EFSCORRUPTED; 426 } 427 428 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); 429 return 0; 430 } 431