1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 2007-2009 Google Inc. and Amit Singh 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 are 9 * met: 10 * 11 * * Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * * Redistributions in binary form must reproduce the above 14 * copyright notice, this list of conditions and the following disclaimer 15 * in the documentation and/or other materials provided with the 16 * distribution. 17 * * Neither the name of Google Inc. nor the names of its 18 * contributors may be used to endorse or promote products derived from 19 * this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 25 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 * 33 * Copyright (C) 2005 Csaba Henk. 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions 38 * are met: 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 45 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND 46 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 47 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 48 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 49 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 50 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 51 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 52 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 53 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 54 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 55 * SUCH DAMAGE. 56 */ 57 58 #include <sys/cdefs.h> 59 __FBSDID("$FreeBSD$"); 60 61 #include <sys/param.h> 62 #include <sys/buf.h> 63 #include <sys/module.h> 64 #include <sys/systm.h> 65 #include <sys/errno.h> 66 #include <sys/kernel.h> 67 #include <sys/capsicum.h> 68 #include <sys/conf.h> 69 #include <sys/filedesc.h> 70 #include <sys/uio.h> 71 #include <sys/malloc.h> 72 #include <sys/queue.h> 73 #include <sys/lock.h> 74 #include <sys/sx.h> 75 #include <sys/mutex.h> 76 #include <sys/proc.h> 77 #include <sys/vnode.h> 78 #include <sys/namei.h> 79 #include <sys/mount.h> 80 #include <sys/sysctl.h> 81 #include <sys/fcntl.h> 82 83 #include "fuse.h" 84 #include "fuse_param.h" 85 #include "fuse_node.h" 86 #include "fuse_ipc.h" 87 #include "fuse_internal.h" 88 89 #include <sys/priv.h> 90 #include <security/mac/mac_framework.h> 91 92 SDT_PROVIDER_DECLARE(fuse); 93 /* 94 * Fuse trace probe: 95 * arg0: verbosity. Higher numbers give more verbose messages 96 * arg1: Textual message 97 */ 98 SDT_PROBE_DEFINE2(fuse, , vfsops, trace, "int", "char*"); 99 100 /* This will do for privilege types for now */ 101 #ifndef PRIV_VFS_FUSE_ALLOWOTHER 102 #define PRIV_VFS_FUSE_ALLOWOTHER PRIV_VFS_MOUNT_NONUSER 103 #endif 104 #ifndef PRIV_VFS_FUSE_MOUNT_NONUSER 105 #define PRIV_VFS_FUSE_MOUNT_NONUSER PRIV_VFS_MOUNT_NONUSER 106 #endif 107 #ifndef PRIV_VFS_FUSE_SYNC_UNMOUNT 108 #define PRIV_VFS_FUSE_SYNC_UNMOUNT PRIV_VFS_MOUNT_NONUSER 109 #endif 110 111 static vfs_mount_t fuse_vfsop_mount; 112 static vfs_unmount_t fuse_vfsop_unmount; 113 static vfs_root_t fuse_vfsop_root; 114 static vfs_statfs_t fuse_vfsop_statfs; 115 116 struct vfsops fuse_vfsops = { 117 .vfs_mount = fuse_vfsop_mount, 118 .vfs_unmount = fuse_vfsop_unmount, 119 .vfs_root = fuse_vfsop_root, 120 .vfs_statfs = fuse_vfsop_statfs, 121 }; 122 123 SYSCTL_INT(_vfs_fusefs, OID_AUTO, init_backgrounded, CTLFLAG_RD, 124 SYSCTL_NULL_INT_PTR, 1, "indicate async handshake"); 125 static int fuse_enforce_dev_perms = 0; 126 127 SYSCTL_INT(_vfs_fusefs, OID_AUTO, enforce_dev_perms, CTLFLAG_RW, 128 &fuse_enforce_dev_perms, 0, 129 "enforce fuse device permissions for secondary mounts"); 130 static unsigned sync_unmount = 1; 131 132 SYSCTL_UINT(_vfs_fusefs, OID_AUTO, sync_unmount, CTLFLAG_RW, 133 &sync_unmount, 0, "specify when to use synchronous unmount"); 134 135 MALLOC_DEFINE(M_FUSEVFS, "fuse_filesystem", "buffer for fuse vfs layer"); 136 137 static int 138 fuse_getdevice(const char *fspec, struct thread *td, struct cdev **fdevp) 139 { 140 struct nameidata nd, *ndp = &nd; 141 struct vnode *devvp; 142 struct cdev *fdev; 143 int err; 144 145 /* 146 * Not an update, or updating the name: look up the name 147 * and verify that it refers to a sensible disk device. 148 */ 149 150 NDINIT(ndp, LOOKUP, FOLLOW, UIO_SYSSPACE, fspec, td); 151 if ((err = namei(ndp)) != 0) 152 return err; 153 NDFREE(ndp, NDF_ONLY_PNBUF); 154 devvp = ndp->ni_vp; 155 156 if (devvp->v_type != VCHR) { 157 vrele(devvp); 158 return ENXIO; 159 } 160 fdev = devvp->v_rdev; 161 dev_ref(fdev); 162 163 if (fuse_enforce_dev_perms) { 164 /* 165 * Check if mounter can open the fuse device. 166 * 167 * This has significance only if we are doing a secondary mount 168 * which doesn't involve actually opening fuse devices, but we 169 * still want to enforce the permissions of the device (in 170 * order to keep control over the circle of fuse users). 171 * 172 * (In case of primary mounts, we are either the superuser so 173 * we can do anything anyway, or we can mount only if the 174 * device is already opened by us, ie. we are permitted to open 175 * the device.) 176 */ 177 #if 0 178 #ifdef MAC 179 err = mac_check_vnode_open(td->td_ucred, devvp, VREAD | VWRITE); 180 if (!err) 181 #endif 182 #endif /* 0 */ 183 err = VOP_ACCESS(devvp, VREAD | VWRITE, td->td_ucred, td); 184 if (err) { 185 vrele(devvp); 186 dev_rel(fdev); 187 return err; 188 } 189 } 190 /* 191 * according to coda code, no extra lock is needed -- 192 * although in sys/vnode.h this field is marked "v" 193 */ 194 vrele(devvp); 195 196 if (!fdev->si_devsw || 197 strcmp("fuse", fdev->si_devsw->d_name)) { 198 dev_rel(fdev); 199 return ENXIO; 200 } 201 *fdevp = fdev; 202 203 return 0; 204 } 205 206 #define FUSE_FLAGOPT(fnam, fval) do { \ 207 vfs_flagopt(opts, #fnam, &mntopts, fval); \ 208 vfs_flagopt(opts, "__" #fnam, &__mntopts, fval); \ 209 } while (0) 210 211 SDT_PROBE_DEFINE1(fuse, , vfsops, mntopts, "uint64_t"); 212 SDT_PROBE_DEFINE4(fuse, , vfsops, mount_err, "char*", "struct fuse_data*", 213 "struct mount*", "int"); 214 215 static int 216 fuse_vfsop_mount(struct mount *mp) 217 { 218 int err; 219 220 uint64_t mntopts, __mntopts; 221 uint32_t max_read; 222 int daemon_timeout; 223 int fd; 224 225 size_t len; 226 227 struct cdev *fdev; 228 struct fuse_data *data = NULL; 229 struct thread *td; 230 struct file *fp, *fptmp; 231 char *fspec, *subtype; 232 struct vfsoptlist *opts; 233 234 subtype = NULL; 235 max_read = ~0; 236 err = 0; 237 mntopts = 0; 238 __mntopts = 0; 239 td = curthread; 240 241 if (mp->mnt_flag & MNT_UPDATE) 242 return EOPNOTSUPP; 243 244 MNT_ILOCK(mp); 245 mp->mnt_flag |= MNT_SYNCHRONOUS; 246 mp->mnt_data = NULL; 247 MNT_IUNLOCK(mp); 248 /* Get the new options passed to mount */ 249 opts = mp->mnt_optnew; 250 251 if (!opts) 252 return EINVAL; 253 254 /* `fspath' contains the mount point (eg. /mnt/fuse/sshfs); REQUIRED */ 255 if (!vfs_getopts(opts, "fspath", &err)) 256 return err; 257 258 /* `from' contains the device name (eg. /dev/fuse0); REQUIRED */ 259 fspec = vfs_getopts(opts, "from", &err); 260 if (!fspec) 261 return err; 262 263 /* `fd' contains the filedescriptor for this session; REQUIRED */ 264 if (vfs_scanopt(opts, "fd", "%d", &fd) != 1) 265 return EINVAL; 266 267 err = fuse_getdevice(fspec, td, &fdev); 268 if (err != 0) 269 return err; 270 271 /* 272 * With the help of underscored options the mount program 273 * can inform us from the flags it sets by default 274 */ 275 FUSE_FLAGOPT(allow_other, FSESS_DAEMON_CAN_SPY); 276 FUSE_FLAGOPT(push_symlinks_in, FSESS_PUSH_SYMLINKS_IN); 277 FUSE_FLAGOPT(default_permissions, FSESS_DEFAULT_PERMISSIONS); 278 FUSE_FLAGOPT(no_attrcache, FSESS_NO_ATTRCACHE); 279 FUSE_FLAGOPT(no_readahed, FSESS_NO_READAHEAD); 280 FUSE_FLAGOPT(no_datacache, FSESS_NO_DATACACHE); 281 FUSE_FLAGOPT(no_namecache, FSESS_NO_NAMECACHE); 282 FUSE_FLAGOPT(no_mmap, FSESS_NO_MMAP); 283 FUSE_FLAGOPT(brokenio, FSESS_BROKENIO); 284 285 (void)vfs_scanopt(opts, "max_read=", "%u", &max_read); 286 if (vfs_scanopt(opts, "timeout=", "%u", &daemon_timeout) == 1) { 287 if (daemon_timeout < FUSE_MIN_DAEMON_TIMEOUT) 288 daemon_timeout = FUSE_MIN_DAEMON_TIMEOUT; 289 else if (daemon_timeout > FUSE_MAX_DAEMON_TIMEOUT) 290 daemon_timeout = FUSE_MAX_DAEMON_TIMEOUT; 291 } else { 292 daemon_timeout = FUSE_DEFAULT_DAEMON_TIMEOUT; 293 } 294 subtype = vfs_getopts(opts, "subtype=", &err); 295 296 SDT_PROBE1(fuse, , vfsops, mntopts, mntopts); 297 298 err = fget(td, fd, &cap_read_rights, &fp); 299 if (err != 0) { 300 SDT_PROBE2(fuse, , vfsops, trace, 1, 301 "invalid or not opened device"); 302 goto out; 303 } 304 fptmp = td->td_fpop; 305 td->td_fpop = fp; 306 err = devfs_get_cdevpriv((void **)&data); 307 td->td_fpop = fptmp; 308 fdrop(fp, td); 309 FUSE_LOCK(); 310 if (err != 0 || data == NULL || data->mp != NULL) { 311 err = ENXIO; 312 SDT_PROBE4(fuse, , vfsops, mount_err, 313 "invalid or not opened device", data, mp, err); 314 FUSE_UNLOCK(); 315 goto out; 316 } 317 if (fdata_get_dead(data)) { 318 err = ENOTCONN; 319 SDT_PROBE4(fuse, , vfsops, mount_err, 320 "device is dead during mount", data, mp, err); 321 FUSE_UNLOCK(); 322 goto out; 323 } 324 /* Sanity + permission checks */ 325 if (!data->daemoncred) 326 panic("fuse daemon found, but identity unknown"); 327 if (mntopts & FSESS_DAEMON_CAN_SPY) 328 err = priv_check(td, PRIV_VFS_FUSE_ALLOWOTHER); 329 if (err == 0 && td->td_ucred->cr_uid != data->daemoncred->cr_uid) 330 /* are we allowed to do the first mount? */ 331 err = priv_check(td, PRIV_VFS_FUSE_MOUNT_NONUSER); 332 if (err) { 333 FUSE_UNLOCK(); 334 goto out; 335 } 336 data->ref++; 337 data->mp = mp; 338 data->dataflags |= mntopts; 339 data->max_read = max_read; 340 data->daemon_timeout = daemon_timeout; 341 FUSE_UNLOCK(); 342 343 vfs_getnewfsid(mp); 344 MNT_ILOCK(mp); 345 mp->mnt_data = data; 346 mp->mnt_flag |= MNT_LOCAL; 347 mp->mnt_kern_flag |= MNTK_USES_BCACHE; 348 MNT_IUNLOCK(mp); 349 /* We need this here as this slot is used by getnewvnode() */ 350 mp->mnt_stat.f_iosize = maxbcachebuf; 351 if (subtype) { 352 strlcat(mp->mnt_stat.f_fstypename, ".", MFSNAMELEN); 353 strlcat(mp->mnt_stat.f_fstypename, subtype, MFSNAMELEN); 354 } 355 copystr(fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &len); 356 bzero(mp->mnt_stat.f_mntfromname + len, MNAMELEN - len); 357 358 /* Now handshaking with daemon */ 359 fuse_internal_send_init(data, td); 360 361 out: 362 if (err) { 363 FUSE_LOCK(); 364 if (data != NULL && data->mp == mp) { 365 /* 366 * Destroy device only if we acquired reference to 367 * it 368 */ 369 SDT_PROBE4(fuse, , vfsops, mount_err, 370 "mount failed, destroy device", data, mp, err); 371 data->mp = NULL; 372 fdata_trydestroy(data); 373 } 374 FUSE_UNLOCK(); 375 dev_rel(fdev); 376 } 377 return err; 378 } 379 380 static int 381 fuse_vfsop_unmount(struct mount *mp, int mntflags) 382 { 383 int err = 0; 384 int flags = 0; 385 386 struct cdev *fdev; 387 struct fuse_data *data; 388 struct fuse_dispatcher fdi; 389 struct thread *td = curthread; 390 391 if (mntflags & MNT_FORCE) { 392 flags |= FORCECLOSE; 393 } 394 data = fuse_get_mpdata(mp); 395 if (!data) { 396 panic("no private data for mount point?"); 397 } 398 /* There is 1 extra root vnode reference (mp->mnt_data). */ 399 FUSE_LOCK(); 400 if (data->vroot != NULL) { 401 struct vnode *vroot = data->vroot; 402 403 data->vroot = NULL; 404 FUSE_UNLOCK(); 405 vrele(vroot); 406 } else 407 FUSE_UNLOCK(); 408 err = vflush(mp, 0, flags, td); 409 if (err) { 410 return err; 411 } 412 if (fdata_get_dead(data)) { 413 goto alreadydead; 414 } 415 fdisp_init(&fdi, 0); 416 fdisp_make(&fdi, FUSE_DESTROY, mp, 0, td, NULL); 417 418 err = fdisp_wait_answ(&fdi); 419 fdisp_destroy(&fdi); 420 421 fdata_set_dead(data); 422 423 alreadydead: 424 FUSE_LOCK(); 425 data->mp = NULL; 426 fdev = data->fdev; 427 fdata_trydestroy(data); 428 FUSE_UNLOCK(); 429 430 MNT_ILOCK(mp); 431 mp->mnt_data = NULL; 432 mp->mnt_flag &= ~MNT_LOCAL; 433 MNT_IUNLOCK(mp); 434 435 dev_rel(fdev); 436 437 return 0; 438 } 439 440 static int 441 fuse_vfsop_root(struct mount *mp, int lkflags, struct vnode **vpp) 442 { 443 struct fuse_data *data = fuse_get_mpdata(mp); 444 int err = 0; 445 446 if (data->vroot != NULL) { 447 err = vget(data->vroot, lkflags, curthread); 448 if (err == 0) 449 *vpp = data->vroot; 450 } else { 451 err = fuse_vnode_get(mp, NULL, FUSE_ROOT_ID, NULL, vpp, NULL, 452 VDIR); 453 if (err == 0) { 454 FUSE_LOCK(); 455 MPASS(data->vroot == NULL || data->vroot == *vpp); 456 if (data->vroot == NULL) { 457 SDT_PROBE2(fuse, , vfsops, trace, 1, 458 "new root vnode"); 459 data->vroot = *vpp; 460 FUSE_UNLOCK(); 461 vref(*vpp); 462 } else if (data->vroot != *vpp) { 463 SDT_PROBE2(fuse, , vfsops, trace, 1, 464 "root vnode race"); 465 FUSE_UNLOCK(); 466 VOP_UNLOCK(*vpp, 0); 467 vrele(*vpp); 468 vrecycle(*vpp); 469 *vpp = data->vroot; 470 } else 471 FUSE_UNLOCK(); 472 } 473 } 474 return err; 475 } 476 477 static int 478 fuse_vfsop_statfs(struct mount *mp, struct statfs *sbp) 479 { 480 struct fuse_dispatcher fdi; 481 int err = 0; 482 483 struct fuse_statfs_out *fsfo; 484 struct fuse_data *data; 485 486 data = fuse_get_mpdata(mp); 487 488 if (!(data->dataflags & FSESS_INITED)) 489 goto fake; 490 491 fdisp_init(&fdi, 0); 492 fdisp_make(&fdi, FUSE_STATFS, mp, FUSE_ROOT_ID, NULL, NULL); 493 err = fdisp_wait_answ(&fdi); 494 if (err) { 495 fdisp_destroy(&fdi); 496 if (err == ENOTCONN) { 497 /* 498 * We want to seem a legitimate fs even if the daemon 499 * is stiff dead... (so that, eg., we can still do path 500 * based unmounting after the daemon dies). 501 */ 502 goto fake; 503 } 504 return err; 505 } 506 fsfo = fdi.answ; 507 508 sbp->f_blocks = fsfo->st.blocks; 509 sbp->f_bfree = fsfo->st.bfree; 510 sbp->f_bavail = fsfo->st.bavail; 511 sbp->f_files = fsfo->st.files; 512 sbp->f_ffree = fsfo->st.ffree; /* cast from uint64_t to int64_t */ 513 sbp->f_namemax = fsfo->st.namelen; 514 sbp->f_bsize = fsfo->st.frsize; /* cast from uint32_t to uint64_t */ 515 516 fdisp_destroy(&fdi); 517 return 0; 518 519 fake: 520 sbp->f_blocks = 0; 521 sbp->f_bfree = 0; 522 sbp->f_bavail = 0; 523 sbp->f_files = 0; 524 sbp->f_ffree = 0; 525 sbp->f_namemax = 0; 526 sbp->f_bsize = FUSE_DEFAULT_BLOCKSIZE; 527 528 return 0; 529 } 530