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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/nfsd/nfsfh.c

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14 KiB
C
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/*
* linux/fs/nfsd/nfsfh.c
*
* NFS server file handle treatment.
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
* Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
* Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
* ... and again Southern-Winter 2001 to support export_operations
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/fs.h>
#include <linux/unistd.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/dcache.h>
#include <linux/mount.h>
#include <asm/pgtable.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#define NFSDDBG_FACILITY NFSDDBG_FH
#define NFSD_PARANOIA 1
/* #define NFSD_DEBUG_VERBOSE 1 */
static int nfsd_nr_verified;
static int nfsd_nr_put;
extern struct export_operations export_op_default;
#define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
/*
* our acceptability function.
* if NOSUBTREECHECK, accept anything
* if not, require that we can walk up to exp->ex_dentry
* doing some checks on the 'x' bits
*/
static int nfsd_acceptable(void *expv, struct dentry *dentry)
{
struct svc_export *exp = expv;
int rv;
struct dentry *tdentry;
struct dentry *parent;
if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
return 1;
tdentry = dget(dentry);
while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
/* make sure parents give x permission to user */
int err;
parent = dget_parent(tdentry);
err = permission(parent->d_inode, MAY_EXEC, NULL);
if (err < 0) {
dput(parent);
break;
}
dput(tdentry);
tdentry = parent;
}
if (tdentry != exp->ex_dentry)
dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
rv = (tdentry == exp->ex_dentry);
dput(tdentry);
return rv;
}
/* Type check. The correct error return for type mismatches does not seem to be
* generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
* comment in the NFSv3 spec says this is incorrect (implementation notes for
* the write call).
*/
static inline __be32
nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
{
/* Type can be negative when creating hardlinks - not to a dir */
if (type > 0 && (mode & S_IFMT) != type) {
if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
return nfserr_symlink;
else if (type == S_IFDIR)
return nfserr_notdir;
else if ((mode & S_IFMT) == S_IFDIR)
return nfserr_isdir;
else
return nfserr_inval;
}
if (type < 0 && (mode & S_IFMT) == -type) {
if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
return nfserr_symlink;
else if (type == -S_IFDIR)
return nfserr_isdir;
else
return nfserr_notdir;
}
return 0;
}
/*
* Perform sanity checks on the dentry in a client's file handle.
*
* Note that the file handle dentry may need to be freed even after
* an error return.
*
* This is only called at the start of an nfsproc call, so fhp points to
* a svc_fh which is all 0 except for the over-the-wire file handle.
*/
__be32
fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
{
struct knfsd_fh *fh = &fhp->fh_handle;
struct svc_export *exp = NULL;
struct dentry *dentry;
__be32 error = 0;
dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
/* keep this filehandle for possible reference when encoding attributes */
rqstp->rq_reffh = fh;
if (!fhp->fh_dentry) {
__u32 *datap=NULL;
__u32 tfh[3]; /* filehandle fragment for oldstyle filehandles */
int fileid_type;
int data_left = fh->fh_size/4;
error = nfserr_stale;
if (rqstp->rq_client == NULL)
goto out;
if (rqstp->rq_vers > 2)
error = nfserr_badhandle;
if (rqstp->rq_vers == 4 && fh->fh_size == 0)
return nfserr_nofilehandle;
if (fh->fh_version == 1) {
int len;
datap = fh->fh_auth;
if (--data_left<0) goto out;
switch (fh->fh_auth_type) {
case 0: break;
default: goto out;
}
len = key_len(fh->fh_fsid_type) / 4;
if (len == 0) goto out;
if (fh->fh_fsid_type == 2) {
/* deprecated, convert to type 3 */
len = 3;
fh->fh_fsid_type = 3;
fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
fh->fh_fsid[1] = fh->fh_fsid[2];
}
if ((data_left -= len)<0) goto out;
exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
datap += len;
} else {
dev_t xdev;
ino_t xino;
if (fh->fh_size != NFS_FHSIZE)
goto out;
/* assume old filehandle format */
xdev = old_decode_dev(fh->ofh_xdev);
xino = u32_to_ino_t(fh->ofh_xino);
mk_fsid_v0(tfh, xdev, xino);
exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle);
}
if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
|| PTR_ERR(exp) == -ETIMEDOUT)) {
error = nfserrno(PTR_ERR(exp));
goto out;
}
error = nfserr_stale;
if (!exp || IS_ERR(exp))
goto out;
/* Check if the request originated from a secure port. */
error = nfserr_perm;
if (!rqstp->rq_secure && EX_SECURE(exp)) {
printk(KERN_WARNING
"nfsd: request from insecure port (%u.%u.%u.%u:%d)!\n",
NIPQUAD(rqstp->rq_addr.sin_addr.s_addr),
ntohs(rqstp->rq_addr.sin_port));
goto out;
}
/* Set user creds for this exportpoint */
error = nfserrno(nfsd_setuser(rqstp, exp));
if (error)
goto out;
/*
* Look up the dentry using the NFS file handle.
*/
error = nfserr_stale;
if (rqstp->rq_vers > 2)
error = nfserr_badhandle;
if (fh->fh_version != 1) {
tfh[0] = fh->ofh_ino;
tfh[1] = fh->ofh_generation;
tfh[2] = fh->ofh_dirino;
datap = tfh;
data_left = 3;
if (fh->ofh_dirino == 0)
fileid_type = 1;
else
fileid_type = 2;
} else
fileid_type = fh->fh_fileid_type;
if (fileid_type == 0)
dentry = dget(exp->ex_dentry);
else {
struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
datap, data_left,
fileid_type,
nfsd_acceptable, exp);
}
if (dentry == NULL)
goto out;
if (IS_ERR(dentry)) {
if (PTR_ERR(dentry) != -EINVAL)
error = nfserrno(PTR_ERR(dentry));
goto out;
}
#ifdef NFSD_PARANOIA
if (S_ISDIR(dentry->d_inode->i_mode) &&
(dentry->d_flags & DCACHE_DISCONNECTED)) {
printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
}
#endif
fhp->fh_dentry = dentry;
fhp->fh_export = exp;
nfsd_nr_verified++;
} else {
/* just rechecking permissions
* (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
*/
dprintk("nfsd: fh_verify - just checking\n");
dentry = fhp->fh_dentry;
exp = fhp->fh_export;
/* Set user creds for this exportpoint; necessary even
* in the "just checking" case because this may be a
* filehandle that was created by fh_compose, and that
* is about to be used in another nfsv4 compound
* operation */
error = nfserrno(nfsd_setuser(rqstp, exp));
if (error)
goto out;
}
cache_get(&exp->h);
error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
if (error)
goto out;
/* Finally, check access permissions. */
error = nfsd_permission(exp, dentry, access);
#ifdef NFSD_PARANOIA_EXTREME
if (error) {
printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n",
dentry->d_parent->d_name.name, dentry->d_name.name, access, (error >> 24));
}
#endif
out:
if (exp && !IS_ERR(exp))
exp_put(exp);
if (error == nfserr_stale)
nfsdstats.fh_stale++;
return error;
}
/*
* Compose a file handle for an NFS reply.
*
* Note that when first composed, the dentry may not yet have
* an inode. In this case a call to fh_update should be made
* before the fh goes out on the wire ...
*/
static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
__u32 *datap, int *maxsize)
{
struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
if (dentry == exp->ex_dentry) {
*maxsize = 0;
return 0;
}
return CALL(nop,encode_fh)(dentry, datap, maxsize,
!(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
}
/*
* for composing old style file handles
*/
static inline void _fh_update_old(struct dentry *dentry,
struct svc_export *exp,
struct knfsd_fh *fh)
{
fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
fh->ofh_generation = dentry->d_inode->i_generation;
if (S_ISDIR(dentry->d_inode->i_mode) ||
(exp->ex_flags & NFSEXP_NOSUBTREECHECK))
fh->ofh_dirino = 0;
}
__be32
fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, struct svc_fh *ref_fh)
{
/* ref_fh is a reference file handle.
* if it is non-null and for the same filesystem, then we should compose
* a filehandle which is of the same version, where possible.
* Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
* Then create a 32byte filehandle using nfs_fhbase_old
*
*/
u8 ref_fh_version = 0;
u8 ref_fh_fsid_type = 0;
struct inode * inode = dentry->d_inode;
struct dentry *parent = dentry->d_parent;
__u32 *datap;
dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
MAJOR(ex_dev), MINOR(ex_dev),
(long) exp->ex_dentry->d_inode->i_ino,
parent->d_name.name, dentry->d_name.name,
(inode ? inode->i_ino : 0));
if (ref_fh && ref_fh->fh_export == exp) {
ref_fh_version = ref_fh->fh_handle.fh_version;
if (ref_fh_version == 0xca)
ref_fh_fsid_type = 0;
else
ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type;
if (ref_fh_fsid_type > 3)
ref_fh_fsid_type = 0;
/* make sure ref_fh type works for given export */
if (ref_fh_fsid_type == 1 &&
!(exp->ex_flags & NFSEXP_FSID)) {
/* if we don't have an fsid, we cannot provide one... */
ref_fh_fsid_type = 0;
}
} else if (exp->ex_flags & NFSEXP_FSID)
ref_fh_fsid_type = 1;
if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) {
/* for newer device numbers, we must use a newer fsid format */
ref_fh_version = 1;
ref_fh_fsid_type = 3;
}
if (old_valid_dev(ex_dev) &&
(ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3))
/* must use type1 for smaller device numbers */
ref_fh_fsid_type = 0;
if (ref_fh == fhp)
fh_put(ref_fh);
if (fhp->fh_locked || fhp->fh_dentry) {
printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
parent->d_name.name, dentry->d_name.name);
}
if (fhp->fh_maxsize < NFS_FHSIZE)
printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);
fhp->fh_dentry = dget(dentry); /* our internal copy */
fhp->fh_export = exp;
cache_get(&exp->h);
if (ref_fh_version == 0xca) {
/* old style filehandle please */
memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
fhp->fh_handle.fh_size = NFS_FHSIZE;
fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev);
fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
if (inode)
_fh_update_old(dentry, exp, &fhp->fh_handle);
} else {
int len;
fhp->fh_handle.fh_version = 1;
fhp->fh_handle.fh_auth_type = 0;
datap = fhp->fh_handle.fh_auth+0;
fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type;
switch (ref_fh_fsid_type) {
case 0:
/*
* fsid_type 0:
* 2byte major, 2byte minor, 4byte inode
*/
mk_fsid_v0(datap, ex_dev,
exp->ex_dentry->d_inode->i_ino);
break;
case 1:
/* fsid_type 1 == 4 bytes filesystem id */
mk_fsid_v1(datap, exp->ex_fsid);
break;
case 2:
/*
* fsid_type 2:
* 4byte major, 4byte minor, 4byte inode
*/
mk_fsid_v2(datap, ex_dev,
exp->ex_dentry->d_inode->i_ino);
break;
case 3:
/*
* fsid_type 3:
* 4byte devicenumber, 4byte inode
*/
mk_fsid_v3(datap, ex_dev,
exp->ex_dentry->d_inode->i_ino);
break;
}
len = key_len(ref_fh_fsid_type);
datap += len/4;
fhp->fh_handle.fh_size = 4 + len;
if (inode) {
int size = (fhp->fh_maxsize-len-4)/4;
fhp->fh_handle.fh_fileid_type =
_fh_update(dentry, exp, datap, &size);
fhp->fh_handle.fh_size += size*4;
}
if (fhp->fh_handle.fh_fileid_type == 255)
return nfserr_opnotsupp;
}
nfsd_nr_verified++;
return 0;
}
/*
* Update file handle information after changing a dentry.
* This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
*/
__be32
fh_update(struct svc_fh *fhp)
{
struct dentry *dentry;
__u32 *datap;
if (!fhp->fh_dentry)
goto out_bad;
dentry = fhp->fh_dentry;
if (!dentry->d_inode)
goto out_negative;
if (fhp->fh_handle.fh_version != 1) {
_fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
} else {
int size;
if (fhp->fh_handle.fh_fileid_type != 0)
goto out;
datap = fhp->fh_handle.fh_auth+
fhp->fh_handle.fh_size/4 -1;
size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
fhp->fh_handle.fh_fileid_type =
_fh_update(dentry, fhp->fh_export, datap, &size);
fhp->fh_handle.fh_size += size*4;
if (fhp->fh_handle.fh_fileid_type == 255)
return nfserr_opnotsupp;
}
out:
return 0;
out_bad:
printk(KERN_ERR "fh_update: fh not verified!\n");
goto out;
out_negative:
printk(KERN_ERR "fh_update: %s/%s still negative!\n",
dentry->d_parent->d_name.name, dentry->d_name.name);
goto out;
}
/*
* Release a file handle.
*/
void
fh_put(struct svc_fh *fhp)
{
struct dentry * dentry = fhp->fh_dentry;
struct svc_export * exp = fhp->fh_export;
if (dentry) {
fh_unlock(fhp);
fhp->fh_dentry = NULL;
dput(dentry);
#ifdef CONFIG_NFSD_V3
fhp->fh_pre_saved = 0;
fhp->fh_post_saved = 0;
#endif
nfsd_nr_put++;
}
if (exp) {
cache_put(&exp->h, &svc_export_cache);
fhp->fh_export = NULL;
}
return;
}
/*
* Shorthand for dprintk()'s
*/
char * SVCFH_fmt(struct svc_fh *fhp)
{
struct knfsd_fh *fh = &fhp->fh_handle;
static char buf[80];
sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
fh->fh_size,
fh->fh_base.fh_pad[0],
fh->fh_base.fh_pad[1],
fh->fh_base.fh_pad[2],
fh->fh_base.fh_pad[3],
fh->fh_base.fh_pad[4],
fh->fh_base.fh_pad[5]);
return buf;
}
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