/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 2007-2009 Google Inc. and Amit Singh * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * Copyright (C) 2005 Csaba Henk. * All rights reserved. * * Copyright (c) 2019 The FreeBSD Foundation * * Portions of this software were developed by BFF Storage Systems, LLC under * sponsorship from the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "fuse.h" #include "fuse_node.h" #include "fuse_ipc.h" #include "fuse_internal.h" #include #include SDT_PROVIDER_DECLARE(fusefs); /* * Fuse trace probe: * arg0: verbosity. Higher numbers give more verbose messages * arg1: Textual message */ SDT_PROBE_DEFINE2(fusefs, , vfsops, trace, "int", "char*"); /* This will do for privilege types for now */ #ifndef PRIV_VFS_FUSE_ALLOWOTHER #define PRIV_VFS_FUSE_ALLOWOTHER PRIV_VFS_MOUNT_NONUSER #endif #ifndef PRIV_VFS_FUSE_MOUNT_NONUSER #define PRIV_VFS_FUSE_MOUNT_NONUSER PRIV_VFS_MOUNT_NONUSER #endif #ifndef PRIV_VFS_FUSE_SYNC_UNMOUNT #define PRIV_VFS_FUSE_SYNC_UNMOUNT PRIV_VFS_MOUNT_NONUSER #endif static vfs_fhtovp_t fuse_vfsop_fhtovp; static vfs_mount_t fuse_vfsop_mount; static vfs_unmount_t fuse_vfsop_unmount; static vfs_root_t fuse_vfsop_root; static vfs_statfs_t fuse_vfsop_statfs; static vfs_vget_t fuse_vfsop_vget; struct vfsops fuse_vfsops = { .vfs_fhtovp = fuse_vfsop_fhtovp, .vfs_mount = fuse_vfsop_mount, .vfs_unmount = fuse_vfsop_unmount, .vfs_root = fuse_vfsop_root, .vfs_statfs = fuse_vfsop_statfs, .vfs_vget = fuse_vfsop_vget, }; static int fuse_enforce_dev_perms = 0; SYSCTL_INT(_vfs_fusefs, OID_AUTO, enforce_dev_perms, CTLFLAG_RW, &fuse_enforce_dev_perms, 0, "enforce fuse device permissions for secondary mounts"); MALLOC_DEFINE(M_FUSEVFS, "fuse_filesystem", "buffer for fuse vfs layer"); static int fuse_getdevice(const char *fspec, struct thread *td, struct cdev **fdevp) { struct nameidata nd, *ndp = &nd; struct vnode *devvp; struct cdev *fdev; int err; /* * Not an update, or updating the name: look up the name * and verify that it refers to a sensible disk device. */ NDINIT(ndp, LOOKUP, FOLLOW, UIO_SYSSPACE, fspec, td); if ((err = namei(ndp)) != 0) return err; NDFREE(ndp, NDF_ONLY_PNBUF); devvp = ndp->ni_vp; if (devvp->v_type != VCHR) { vrele(devvp); return ENXIO; } fdev = devvp->v_rdev; dev_ref(fdev); if (fuse_enforce_dev_perms) { /* * Check if mounter can open the fuse device. * * This has significance only if we are doing a secondary mount * which doesn't involve actually opening fuse devices, but we * still want to enforce the permissions of the device (in * order to keep control over the circle of fuse users). * * (In case of primary mounts, we are either the superuser so * we can do anything anyway, or we can mount only if the * device is already opened by us, ie. we are permitted to open * the device.) */ #if 0 #ifdef MAC err = mac_check_vnode_open(td->td_ucred, devvp, VREAD | VWRITE); if (!err) #endif #endif /* 0 */ err = VOP_ACCESS(devvp, VREAD | VWRITE, td->td_ucred, td); if (err) { vrele(devvp); dev_rel(fdev); return err; } } /* * according to coda code, no extra lock is needed -- * although in sys/vnode.h this field is marked "v" */ vrele(devvp); if (!fdev->si_devsw || strcmp("fuse", fdev->si_devsw->d_name)) { dev_rel(fdev); return ENXIO; } *fdevp = fdev; return 0; } #define FUSE_FLAGOPT(fnam, fval) do { \ vfs_flagopt(opts, #fnam, &mntopts, fval); \ vfs_flagopt(opts, "__" #fnam, &__mntopts, fval); \ } while (0) SDT_PROBE_DEFINE1(fusefs, , vfsops, mntopts, "uint64_t"); SDT_PROBE_DEFINE4(fusefs, , vfsops, mount_err, "char*", "struct fuse_data*", "struct mount*", "int"); static int fuse_vfs_remount(struct mount *mp, struct thread *td, uint64_t mntopts, uint32_t max_read, int daemon_timeout) { int err = 0; struct fuse_data *data = fuse_get_mpdata(mp); /* Don't allow these options to be changed */ const static unsigned long long cant_update_opts = MNT_USER; /* Mount owner must be the user running the daemon */ FUSE_LOCK(); if ((mp->mnt_flag ^ data->mnt_flag) & cant_update_opts) { err = EOPNOTSUPP; SDT_PROBE4(fusefs, , vfsops, mount_err, "Can't change these mount options during remount", data, mp, err); goto out; } if (((data->dataflags ^ mntopts) & FSESS_MNTOPTS_MASK) || (data->max_read != max_read) || (data->daemon_timeout != daemon_timeout)) { // TODO: allow changing options where it makes sense err = EOPNOTSUPP; SDT_PROBE4(fusefs, , vfsops, mount_err, "Can't change fuse mount options during remount", data, mp, err); goto out; } if (fdata_get_dead(data)) { err = ENOTCONN; SDT_PROBE4(fusefs, , vfsops, mount_err, "device is dead during mount", data, mp, err); goto out; } /* Sanity + permission checks */ if (!data->daemoncred) panic("fuse daemon found, but identity unknown"); if (mntopts & FSESS_DAEMON_CAN_SPY) err = priv_check(td, PRIV_VFS_FUSE_ALLOWOTHER); if (err == 0 && td->td_ucred->cr_uid != data->daemoncred->cr_uid) /* are we allowed to do the first mount? */ err = priv_check(td, PRIV_VFS_FUSE_MOUNT_NONUSER); out: FUSE_UNLOCK(); return err; } static int fuse_vfsop_fhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp) { struct fuse_fid *ffhp = (struct fuse_fid *)fhp; struct fuse_vnode_data *fvdat; struct vnode *nvp; int error; if (!(fuse_get_mpdata(mp)->dataflags & FSESS_EXPORT_SUPPORT)) return EOPNOTSUPP; error = VFS_VGET(mp, ffhp->nid, LK_EXCLUSIVE, &nvp); if (error) { *vpp = NULLVP; return (error); } fvdat = VTOFUD(nvp); if (fvdat->generation != ffhp->gen ) { vput(nvp); *vpp = NULLVP; return (ESTALE); } *vpp = nvp; vnode_create_vobject(*vpp, 0, curthread); return (0); } static int fuse_vfsop_mount(struct mount *mp) { int err; uint64_t mntopts, __mntopts; uint32_t max_read; int linux_errnos; int daemon_timeout; int fd; struct cdev *fdev; struct fuse_data *data = NULL; struct thread *td; struct file *fp, *fptmp; char *fspec, *subtype; struct vfsoptlist *opts; subtype = NULL; max_read = ~0; linux_errnos = 0; err = 0; mntopts = 0; __mntopts = 0; td = curthread; /* Get the new options passed to mount */ opts = mp->mnt_optnew; if (!opts) return EINVAL; /* `fspath' contains the mount point (eg. /mnt/fuse/sshfs); REQUIRED */ if (!vfs_getopts(opts, "fspath", &err)) return err; /* * With the help of underscored options the mount program * can inform us from the flags it sets by default */ FUSE_FLAGOPT(allow_other, FSESS_DAEMON_CAN_SPY); FUSE_FLAGOPT(push_symlinks_in, FSESS_PUSH_SYMLINKS_IN); FUSE_FLAGOPT(default_permissions, FSESS_DEFAULT_PERMISSIONS); FUSE_FLAGOPT(intr, FSESS_INTR); (void)vfs_scanopt(opts, "max_read=", "%u", &max_read); (void)vfs_scanopt(opts, "linux_errnos", "%d", &linux_errnos); if (vfs_scanopt(opts, "timeout=", "%u", &daemon_timeout) == 1) { if (daemon_timeout < FUSE_MIN_DAEMON_TIMEOUT) daemon_timeout = FUSE_MIN_DAEMON_TIMEOUT; else if (daemon_timeout > FUSE_MAX_DAEMON_TIMEOUT) daemon_timeout = FUSE_MAX_DAEMON_TIMEOUT; } else { daemon_timeout = FUSE_DEFAULT_DAEMON_TIMEOUT; } subtype = vfs_getopts(opts, "subtype=", &err); SDT_PROBE1(fusefs, , vfsops, mntopts, mntopts); if (mp->mnt_flag & MNT_UPDATE) { return fuse_vfs_remount(mp, td, mntopts, max_read, daemon_timeout); } /* `from' contains the device name (eg. /dev/fuse0); REQUIRED */ fspec = vfs_getopts(opts, "from", &err); if (!fspec) return err; /* `fd' contains the filedescriptor for this session; REQUIRED */ if (vfs_scanopt(opts, "fd", "%d", &fd) != 1) return EINVAL; err = fuse_getdevice(fspec, td, &fdev); if (err != 0) return err; err = fget(td, fd, &cap_read_rights, &fp); if (err != 0) { SDT_PROBE2(fusefs, , vfsops, trace, 1, "invalid or not opened device"); goto out; } fptmp = td->td_fpop; td->td_fpop = fp; err = devfs_get_cdevpriv((void **)&data); td->td_fpop = fptmp; fdrop(fp, td); FUSE_LOCK(); if (err != 0 || data == NULL) { err = ENXIO; SDT_PROBE4(fusefs, , vfsops, mount_err, "invalid or not opened device", data, mp, err); FUSE_UNLOCK(); goto out; } if (fdata_get_dead(data)) { err = ENOTCONN; SDT_PROBE4(fusefs, , vfsops, mount_err, "device is dead during mount", data, mp, err); FUSE_UNLOCK(); goto out; } /* Sanity + permission checks */ if (!data->daemoncred) panic("fuse daemon found, but identity unknown"); if (mntopts & FSESS_DAEMON_CAN_SPY) err = priv_check(td, PRIV_VFS_FUSE_ALLOWOTHER); if (err == 0 && td->td_ucred->cr_uid != data->daemoncred->cr_uid) /* are we allowed to do the first mount? */ err = priv_check(td, PRIV_VFS_FUSE_MOUNT_NONUSER); if (err) { FUSE_UNLOCK(); goto out; } data->ref++; data->mp = mp; data->dataflags |= mntopts; data->max_read = max_read; data->daemon_timeout = daemon_timeout; data->linux_errnos = linux_errnos; data->mnt_flag = mp->mnt_flag & MNT_UPDATEMASK; FUSE_UNLOCK(); vfs_getnewfsid(mp); MNT_ILOCK(mp); mp->mnt_data = data; /* * FUSE file systems can be either local or remote, but the kernel * can't tell the difference. */ mp->mnt_flag &= ~MNT_LOCAL; mp->mnt_kern_flag |= MNTK_USES_BCACHE; /* * Disable nullfs cacheing because it can consume too many resources in * the FUSE server. */ mp->mnt_kern_flag |= MNTK_NULL_NOCACHE; MNT_IUNLOCK(mp); /* We need this here as this slot is used by getnewvnode() */ mp->mnt_stat.f_iosize = maxbcachebuf; if (subtype) { strlcat(mp->mnt_stat.f_fstypename, ".", MFSNAMELEN); strlcat(mp->mnt_stat.f_fstypename, subtype, MFSNAMELEN); } memset(mp->mnt_stat.f_mntfromname, 0, MNAMELEN); strlcpy(mp->mnt_stat.f_mntfromname, fspec, MNAMELEN); mp->mnt_iosize_max = maxphys; /* Now handshaking with daemon */ fuse_internal_send_init(data, td); out: if (err) { FUSE_LOCK(); if (data != NULL && data->mp == mp) { /* * Destroy device only if we acquired reference to * it */ SDT_PROBE4(fusefs, , vfsops, mount_err, "mount failed, destroy device", data, mp, err); data->mp = NULL; mp->mnt_data = NULL; fdata_trydestroy(data); } FUSE_UNLOCK(); dev_rel(fdev); } return err; } static int fuse_vfsop_unmount(struct mount *mp, int mntflags) { int err = 0; int flags = 0; struct cdev *fdev; struct fuse_data *data; struct fuse_dispatcher fdi; struct thread *td = curthread; if (mntflags & MNT_FORCE) { flags |= FORCECLOSE; } data = fuse_get_mpdata(mp); if (!data) { panic("no private data for mount point?"); } /* There is 1 extra root vnode reference (mp->mnt_data). */ FUSE_LOCK(); if (data->vroot != NULL) { struct vnode *vroot = data->vroot; data->vroot = NULL; FUSE_UNLOCK(); vrele(vroot); } else FUSE_UNLOCK(); err = vflush(mp, 0, flags, td); if (err) { return err; } if (fdata_get_dead(data)) { goto alreadydead; } if (fsess_maybe_impl(mp, FUSE_DESTROY)) { fdisp_init(&fdi, 0); fdisp_make(&fdi, FUSE_DESTROY, mp, 0, td, NULL); (void)fdisp_wait_answ(&fdi); fdisp_destroy(&fdi); } fdata_set_dead(data); alreadydead: FUSE_LOCK(); data->mp = NULL; fdev = data->fdev; fdata_trydestroy(data); FUSE_UNLOCK(); MNT_ILOCK(mp); mp->mnt_data = NULL; MNT_IUNLOCK(mp); dev_rel(fdev); return 0; } SDT_PROBE_DEFINE1(fusefs, , vfsops, invalidate_without_export, "struct mount*"); static int fuse_vfsop_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp) { struct fuse_data *data = fuse_get_mpdata(mp); uint64_t nodeid = ino; struct thread *td = curthread; struct fuse_dispatcher fdi; struct fuse_entry_out *feo; struct fuse_vnode_data *fvdat; const char dot[] = "."; off_t filesize; enum vtype vtyp; int error; if (!(data->dataflags & FSESS_EXPORT_SUPPORT)) { /* * Unreachable unless you do something stupid, like export a * nullfs mount of a fusefs file system. */ SDT_PROBE1(fusefs, , vfsops, invalidate_without_export, mp); return (EOPNOTSUPP); } error = fuse_internal_get_cached_vnode(mp, ino, flags, vpp); if (error || *vpp != NULL) return error; /* Do a LOOKUP, using nodeid as the parent and "." as filename */ fdisp_init(&fdi, sizeof(dot)); fdisp_make(&fdi, FUSE_LOOKUP, mp, nodeid, td, td->td_ucred); memcpy(fdi.indata, dot, sizeof(dot)); error = fdisp_wait_answ(&fdi); if (error) return error; feo = (struct fuse_entry_out *)fdi.answ; if (feo->nodeid == 0) { /* zero nodeid means ENOENT and cache it */ error = ENOENT; goto out; } vtyp = IFTOVT(feo->attr.mode); error = fuse_vnode_get(mp, feo, nodeid, NULL, vpp, NULL, vtyp); if (error) goto out; filesize = feo->attr.size; /* * In the case where we are looking up a FUSE node represented by an * existing cached vnode, and the true size reported by FUSE_LOOKUP * doesn't match the vnode's cached size, then any cached writes beyond * the file's current size are lost. * * We can get here: * * following attribute cache expiration, or * * due a bug in the daemon, or */ fvdat = VTOFUD(*vpp); if (vnode_isreg(*vpp) && filesize != fvdat->cached_attrs.va_size && fvdat->flag & FN_SIZECHANGE) { if (data->cache_mode == fuse_data_cache_mode) { const char *msg; if (fuse_libabi_geq(data, 7, 23)) { msg = "writeback cache incoherent!." "To prevent data corruption, disable " "the writeback cache according to your " "FUSE server's documentation."; } else { msg = "writeback cache incoherent!." "To prevent data corruption, disable " "the writeback cache by setting " "vfs.fusefs.data_cache_mode to 0 or 1."; } fuse_warn(data, FSESS_WARN_WB_CACHE_INCOHERENT, msg); } else { /* If we get here, it's likely a fusefs kernel bug */ printf("%s: WB cache incoherent on %s!\n", __func__, vnode_mount(*vpp)->mnt_stat.f_mntonname); } fvdat->flag &= ~FN_SIZECHANGE; } fuse_internal_cache_attrs(*vpp, &feo->attr, feo->attr_valid, feo->attr_valid_nsec, NULL); fuse_validity_2_bintime(feo->entry_valid, feo->entry_valid_nsec, &fvdat->entry_cache_timeout); out: fdisp_destroy(&fdi); return error; } static int fuse_vfsop_root(struct mount *mp, int lkflags, struct vnode **vpp) { struct fuse_data *data = fuse_get_mpdata(mp); int err = 0; if (data->vroot != NULL) { err = vget(data->vroot, lkflags); if (err == 0) *vpp = data->vroot; } else { err = fuse_vnode_get(mp, NULL, FUSE_ROOT_ID, NULL, vpp, NULL, VDIR); if (err == 0) { FUSE_LOCK(); MPASS(data->vroot == NULL || data->vroot == *vpp); if (data->vroot == NULL) { SDT_PROBE2(fusefs, , vfsops, trace, 1, "new root vnode"); data->vroot = *vpp; FUSE_UNLOCK(); vref(*vpp); } else if (data->vroot != *vpp) { SDT_PROBE2(fusefs, , vfsops, trace, 1, "root vnode race"); FUSE_UNLOCK(); VOP_UNLOCK(*vpp); vrele(*vpp); vrecycle(*vpp); *vpp = data->vroot; } else FUSE_UNLOCK(); } } return err; } static int fuse_vfsop_statfs(struct mount *mp, struct statfs *sbp) { struct fuse_dispatcher fdi; int err = 0; struct fuse_statfs_out *fsfo; struct fuse_data *data; data = fuse_get_mpdata(mp); if (!(data->dataflags & FSESS_INITED)) goto fake; fdisp_init(&fdi, 0); fdisp_make(&fdi, FUSE_STATFS, mp, FUSE_ROOT_ID, NULL, NULL); err = fdisp_wait_answ(&fdi); if (err) { fdisp_destroy(&fdi); if (err == ENOTCONN) { /* * We want to seem a legitimate fs even if the daemon * is stiff dead... (so that, eg., we can still do path * based unmounting after the daemon dies). */ goto fake; } return err; } fsfo = fdi.answ; sbp->f_blocks = fsfo->st.blocks; sbp->f_bfree = fsfo->st.bfree; sbp->f_bavail = fsfo->st.bavail; sbp->f_files = fsfo->st.files; sbp->f_ffree = fsfo->st.ffree; /* cast from uint64_t to int64_t */ sbp->f_namemax = fsfo->st.namelen; sbp->f_bsize = fsfo->st.frsize; /* cast from uint32_t to uint64_t */ fdisp_destroy(&fdi); return 0; fake: sbp->f_blocks = 0; sbp->f_bfree = 0; sbp->f_bavail = 0; sbp->f_files = 0; sbp->f_ffree = 0; sbp->f_namemax = 0; sbp->f_bsize = S_BLKSIZE; return 0; }