freebsd-dev/sys/fs/fuse/fuse_vfsops.c
Attilio Rao 1750b7b9c8 - Protect mnt_data and mnt_flags under the mount interlock
- Move mp->mnt_stat manipulation where all of them happens

Reported by:	davide
Discussed with:	kib
Tested by:	flo
MFC after:	2 months
X-MFC:		241519, 242536,242616, 242727
2012-11-10 19:32:16 +00:00

533 lines
14 KiB
C

/*
* 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/types.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/capability.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_param.h"
#include "fuse_node.h"
#include "fuse_ipc.h"
#include "fuse_internal.h"
#include <sys/priv.h>
#include <security/mac/mac_framework.h>
#define FUSE_DEBUG_MODULE VFSOPS
#include "fuse_debug.h"
/* 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_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;
struct vfsops fuse_vfsops = {
.vfs_mount = fuse_vfsop_mount,
.vfs_unmount = fuse_vfsop_unmount,
.vfs_root = fuse_vfsop_root,
.vfs_statfs = fuse_vfsop_statfs,
};
SYSCTL_INT(_vfs_fuse, OID_AUTO, init_backgrounded, CTLFLAG_RD,
0, 1, "indicate async handshake");
static int fuse_enforce_dev_perms = 0;
SYSCTL_LONG(_vfs_fuse, OID_AUTO, enforce_dev_perms, CTLFLAG_RW,
&fuse_enforce_dev_perms, 0,
"enforce fuse device permissions for secondary mounts");
static unsigned sync_unmount = 1;
SYSCTL_UINT(_vfs_fuse, OID_AUTO, sync_unmount, CTLFLAG_RW,
&sync_unmount, 0, "specify when to use synchronous unmount");
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)
static int
fuse_vfsop_mount(struct mount *mp)
{
int err;
uint64_t mntopts, __mntopts;
int max_read_set;
uint32_t max_read;
int daemon_timeout;
int fd;
size_t len;
struct cdev *fdev;
struct fuse_data *data;
struct thread *td;
struct file *fp, *fptmp;
char *fspec, *subtype;
struct vfsoptlist *opts;
subtype = NULL;
max_read_set = 0;
max_read = ~0;
err = 0;
mntopts = 0;
__mntopts = 0;
td = curthread;
fuse_trace_printf_vfsop();
if (mp->mnt_flag & MNT_UPDATE)
return EOPNOTSUPP;
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_SYNCHRONOUS;
mp->mnt_data = NULL;
MNT_IUNLOCK(mp);
/* 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;
/* `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;
/*
* 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);
FUSE_FLAGOPT(brokenio, FSESS_BROKENIO);
if (vfs_scanopt(opts, "max_read=", "%u", &max_read) == 1)
max_read_set = 1;
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);
FS_DEBUG2G("mntopts 0x%jx\n", (uintmax_t)mntopts);
err = fget(td, fd, CAP_READ, &fp);
if (err != 0) {
FS_DEBUG("invalid or not opened device: data=%p\n", data);
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 || data->mp != NULL) {
FS_DEBUG("invalid or not opened device: data=%p data.mp=%p\n",
data, data != NULL ? data->mp : NULL);
err = ENXIO;
FUSE_UNLOCK();
goto out;
}
if (fdata_get_dead(data)) {
FS_DEBUG("device is dead during mount: data=%p\n", data);
err = ENOTCONN;
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;
FUSE_UNLOCK();
vfs_getnewfsid(mp);
MNT_ILOCK(mp);
mp->mnt_data = data;
mp->mnt_flag |= MNT_LOCAL;
MNT_IUNLOCK(mp);
/* We need this here as this slot is used by getnewvnode() */
mp->mnt_stat.f_iosize = PAGE_SIZE;
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);
FS_DEBUG2G("mp %p: %s\n", mp, mp->mnt_stat.f_mntfromname);
/* Now handshaking with daemon */
fuse_internal_send_init(data, td);
out:
if (err) {
FUSE_LOCK();
if (data->mp == mp) {
/*
* Destroy device only if we acquired reference to
* it
*/
FS_DEBUG("mount failed, destroy device: data=%p mp=%p"
" err=%d\n",
data, mp, err);
data->mp = 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;
fuse_trace_printf_vfsop();
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) {
debug_printf("vflush failed");
return err;
}
if (fdata_get_dead(data)) {
goto alreadydead;
}
fdisp_init(&fdi, 0);
fdisp_make(&fdi, FUSE_DESTROY, mp, 0, td, NULL);
err = 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;
mp->mnt_flag &= ~MNT_LOCAL;
MNT_IUNLOCK(mp);
dev_rel(fdev);
return 0;
}
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, FUSE_ROOT_ID, NULL, vpp, NULL, VDIR);
if (err == 0) {
FUSE_LOCK();
MPASS(data->vroot == NULL || data->vroot == *vpp);
if (data->vroot == NULL) {
FS_DEBUG("new root vnode\n");
data->vroot = *vpp;
FUSE_UNLOCK();
vref(*vpp);
} else if (data->vroot != *vpp) {
FS_DEBUG("root vnode race\n");
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;
FS_DEBUG2G("mp %p: %s\n", mp, mp->mnt_stat.f_mntfromname);
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 */
FS_DEBUG("fuse_statfs_out -- blocks: %llu, bfree: %llu, bavail: %llu, "
"fil es: %llu, ffree: %llu, bsize: %i, namelen: %i\n",
(unsigned long long)fsfo->st.blocks,
(unsigned long long)fsfo->st.bfree,
(unsigned long long)fsfo->st.bavail,
(unsigned long long)fsfo->st.files,
(unsigned long long)fsfo->st.ffree, fsfo->st.bsize,
fsfo->st.namelen);
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 = FUSE_DEFAULT_BLOCKSIZE;
return 0;
}