freebsd-dev/sys/fs/fuse/fuse_vfsops.c
Alan Somers 192a918194 fusefs: attempt to support servers as old as protocol 7.4
Previously we allowed servers as old as 7.1 to connect (there never was a
7.0).  However, we wrongly assumed a few things about protocols older than
7.8.  This commit attempts to support servers as old as 7.4 but no older.  I
added no new tests because I'm not sure there actually _are_ any servers
this old in the wild.

Sponsored by:	The FreeBSD Foundation
2019-06-20 22:21:42 +00:00

692 lines
18 KiB
C

/*-
* 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.
*
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/buf.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/capsicum.h>
#include <sys/conf.h>
#include <sys/filedesc.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/lock.h>
#include <sys/sx.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <sys/fcntl.h>
#include "fuse.h"
#include "fuse_node.h"
#include "fuse_ipc.h"
#include "fuse_internal.h"
#include <sys/priv.h>
#include <security/mac/mac_framework.h>
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 daemon_timeout;
int fd;
size_t len;
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;
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(no_attrcache, FSESS_NO_ATTRCACHE);
FUSE_FLAGOPT(no_readahed, FSESS_NO_READAHEAD);
FUSE_FLAGOPT(no_datacache, FSESS_NO_DATACACHE);
FUSE_FLAGOPT(no_namecache, FSESS_NO_NAMECACHE);
FUSE_FLAGOPT(no_mmap, FSESS_NO_MMAP);
(void)vfs_scanopt(opts, "max_read=", "%u", &max_read);
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->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;
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);
}
copystr(fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &len);
bzero(mp->mnt_stat.f_mntfromname + len, MNAMELEN - len);
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_isimpl(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) {
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, curthread);
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, 0);
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;
}