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OpenCloudOS-Kernel/fs/nfsd/nfsfh.c

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/*
* 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/exportfs.h>
#include <linux/sunrpc/svcauth_gss.h>
#include "nfsd.h"
#include "vfs.h"
#include "auth.h"
#define NFSDDBG_FACILITY NFSDDBG_FH
/*
* 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_path.dentry && !IS_ROOT(tdentry)) {
/* make sure parents give x permission to user */
int err;
parent = dget_parent(tdentry);
err = inode_permission(parent->d_inode, MAY_EXEC);
if (err < 0) {
dput(parent);
break;
}
dput(tdentry);
tdentry = parent;
}
if (tdentry != exp->ex_path.dentry)
dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
rv = (tdentry == exp->ex_path.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;
}
static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
struct svc_export *exp)
{
int flags = nfsexp_flags(rqstp, exp);
/* Check if the request originated from a secure port. */
if (!rqstp->rq_secure && !(flags & NFSEXP_INSECURE_PORT)) {
RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
dprintk(KERN_WARNING
"nfsd: request from insecure port %s!\n",
svc_print_addr(rqstp, buf, sizeof(buf)));
return nfserr_perm;
}
/* Set user creds for this exportpoint */
return nfserrno(nfsd_setuser(rqstp, exp));
}
static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
struct dentry *dentry, struct svc_export *exp)
{
if (!(exp->ex_flags & NFSEXP_V4ROOT))
return nfs_ok;
/*
* v2/v3 clients have no need for the V4ROOT export--they use
* the mount protocl instead; also, further V4ROOT checks may be
* in v4-specific code, in which case v2/v3 clients could bypass
* them.
*/
if (!nfsd_v4client(rqstp))
return nfserr_stale;
/*
* We're exposing only the directories and symlinks that have to be
* traversed on the way to real exports:
*/
if (unlikely(!S_ISDIR(dentry->d_inode->i_mode) &&
!S_ISLNK(dentry->d_inode->i_mode)))
return nfserr_stale;
/*
* A pseudoroot export gives permission to access only one
* single directory; the kernel has to make another upcall
* before granting access to anything else under it:
*/
if (unlikely(dentry != exp->ex_path.dentry))
return nfserr_stale;
return nfs_ok;
}
/*
* Use the given filehandle to look up the corresponding export and
* dentry. On success, the results are used to set fh_export and
* fh_dentry.
*/
static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
{
struct knfsd_fh *fh = &fhp->fh_handle;
struct fid *fid = NULL, sfid;
struct svc_export *exp;
struct dentry *dentry;
int fileid_type;
int data_left = fh->fh_size/4;
__be32 error;
error = nfserr_stale;
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;
if (--data_left < 0)
return error;
if (fh->fh_auth_type != 0)
return error;
len = key_len(fh->fh_fsid_type) / 4;
if (len == 0)
return error;
if (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
/* deprecated, convert to type 3 */
len = key_len(FSID_ENCODE_DEV)/4;
fh->fh_fsid_type = FSID_ENCODE_DEV;
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];
}
data_left -= len;
if (data_left < 0)
return error;
exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
fid = (struct fid *)(fh->fh_auth + len);
} else {
__u32 tfh[2];
dev_t xdev;
ino_t xino;
if (fh->fh_size != NFS_FHSIZE)
return error;
/* assume old filehandle format */
xdev = old_decode_dev(fh->ofh_xdev);
xino = u32_to_ino_t(fh->ofh_xino);
mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
}
error = nfserr_stale;
if (PTR_ERR(exp) == -ENOENT)
return error;
if (IS_ERR(exp))
return nfserrno(PTR_ERR(exp));
if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
/* Elevate privileges so that the lack of 'r' or 'x'
* permission on some parent directory will
* not stop exportfs_decode_fh from being able
* to reconnect a directory into the dentry cache.
* The same problem can affect "SUBTREECHECK" exports,
* but as nfsd_acceptable depends on correct
* access control settings being in effect, we cannot
* fix that case easily.
*/
struct cred *new = prepare_creds();
if (!new)
return nfserrno(-ENOMEM);
new->cap_effective =
cap_raise_nfsd_set(new->cap_effective,
new->cap_permitted);
put_cred(override_creds(new));
put_cred(new);
} else {
error = nfsd_setuser_and_check_port(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) {
sfid.i32.ino = fh->ofh_ino;
sfid.i32.gen = fh->ofh_generation;
sfid.i32.parent_ino = fh->ofh_dirino;
fid = &sfid;
data_left = 3;
if (fh->ofh_dirino == 0)
fileid_type = FILEID_INO32_GEN;
else
fileid_type = FILEID_INO32_GEN_PARENT;
} else
fileid_type = fh->fh_fileid_type;
if (fileid_type == FILEID_ROOT)
dentry = dget(exp->ex_path.dentry);
else {
dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
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;
}
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);
}
fhp->fh_dentry = dentry;
fhp->fh_export = exp;
return 0;
out:
exp_put(exp);
return error;
}
/**
* fh_verify - filehandle lookup and access checking
* @rqstp: pointer to current rpc request
* @fhp: filehandle to be verified
* @type: expected type of object pointed to by filehandle
* @access: type of access needed to object
*
* Look up a dentry from the on-the-wire filehandle, check the client's
* access to the export, and set the current task's credentials.
*
* Regardless of success or failure of fh_verify(), fh_put() should be
* called on @fhp when the caller is finished with the filehandle.
*
* fh_verify() may be called multiple times on a given filehandle, for
* example, when processing an NFSv4 compound. The first call will look
* up a dentry using the on-the-wire filehandle. Subsequent calls will
* skip the lookup and just perform the other checks and possibly change
* the current task's credentials.
*
* @type specifies the type of object expected using one of the S_IF*
* constants defined in include/linux/stat.h. The caller may use zero
* to indicate that it doesn't care, or a negative integer to indicate
* that it expects something not of the given type.
*
* @access is formed from the NFSD_MAY_* constants defined in
* include/linux/nfsd/nfsd.h.
*/
__be32
fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
{
struct svc_export *exp;
struct dentry *dentry;
__be32 error;
dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
if (!fhp->fh_dentry) {
error = nfsd_set_fh_dentry(rqstp, fhp);
if (error)
goto out;
}
dentry = fhp->fh_dentry;
exp = fhp->fh_export;
/*
* We still have to do all these permission checks, even when
* fh_dentry is already set:
* - fh_verify may be called multiple times with different
* "access" arguments (e.g. nfsd_proc_create calls
* fh_verify(...,NFSD_MAY_EXEC) first, then later (in
* nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
* - in the NFSv4 case, the filehandle may have been filled
* in by fh_compose, and given a dentry, but further
* compound operations performed with that filehandle
* still need permissions checks. In the worst case, a
* mountpoint crossing may have changed the export
* options, and we may now need to use a different uid
* (for example, if different id-squashing options are in
* effect on the new filesystem).
*/
error = check_pseudo_root(rqstp, dentry, exp);
if (error)
goto out;
error = nfsd_setuser_and_check_port(rqstp, exp);
if (error)
goto out;
error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
if (error)
goto out;
/*
* pseudoflavor restrictions are not enforced on NLM,
* which clients virtually always use auth_sys for,
* even while using RPCSEC_GSS for NFS.
*/
if (access & NFSD_MAY_LOCK)
goto skip_pseudoflavor_check;
/*
* Clients may expect to be able to use auth_sys during mount,
* even if they use gss for everything else; see section 2.3.2
* of rfc 2623.
*/
if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
&& exp->ex_path.dentry == dentry)
goto skip_pseudoflavor_check;
error = check_nfsd_access(exp, rqstp);
if (error)
goto out;
skip_pseudoflavor_check:
/* Finally, check access permissions. */
error = nfsd_permission(rqstp, exp, dentry, access);
if (error) {
dprintk("fh_verify: %s/%s permission failure, "
"acc=%x, error=%d\n",
dentry->d_parent->d_name.name,
dentry->d_name.name,
access, ntohl(error));
}
out:
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 void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
struct dentry *dentry)
{
if (dentry != exp->ex_path.dentry) {
struct fid *fid = (struct fid *)
(fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
fhp->fh_handle.fh_fileid_type =
exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
fhp->fh_handle.fh_size += maxsize * 4;
} else {
fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
}
}
/*
* 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;
}
static bool is_root_export(struct svc_export *exp)
{
return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
}
static struct super_block *exp_sb(struct svc_export *exp)
{
return exp->ex_path.dentry->d_inode->i_sb;
}
static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
{
switch (fsid_type) {
case FSID_DEV:
if (!old_valid_dev(exp_sb(exp)->s_dev))
return 0;
/* FALL THROUGH */
case FSID_MAJOR_MINOR:
case FSID_ENCODE_DEV:
return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
case FSID_NUM:
return exp->ex_flags & NFSEXP_FSID;
case FSID_UUID8:
case FSID_UUID16:
if (!is_root_export(exp))
return 0;
/* fall through */
case FSID_UUID4_INUM:
case FSID_UUID16_INUM:
return exp->ex_uuid != NULL;
}
return 1;
}
static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
{
u8 version;
u8 fsid_type;
retry:
version = 1;
if (ref_fh && ref_fh->fh_export == exp) {
version = ref_fh->fh_handle.fh_version;
fsid_type = ref_fh->fh_handle.fh_fsid_type;
ref_fh = NULL;
switch (version) {
case 0xca:
fsid_type = FSID_DEV;
break;
case 1:
break;
default:
goto retry;
}
/*
* As the fsid -> filesystem mapping was guided by
* user-space, there is no guarantee that the filesystem
* actually supports that fsid type. If it doesn't we
* loop around again without ref_fh set.
*/
if (!fsid_type_ok_for_exp(fsid_type, exp))
goto retry;
} else if (exp->ex_flags & NFSEXP_FSID) {
fsid_type = FSID_NUM;
} else if (exp->ex_uuid) {
if (fhp->fh_maxsize >= 64) {
if (is_root_export(exp))
fsid_type = FSID_UUID16;
else
fsid_type = FSID_UUID16_INUM;
} else {
if (is_root_export(exp))
fsid_type = FSID_UUID8;
else
fsid_type = FSID_UUID4_INUM;
}
} else if (!old_valid_dev(exp_sb(exp)->s_dev))
/* for newer device numbers, we must use a newer fsid format */
fsid_type = FSID_ENCODE_DEV;
else
fsid_type = FSID_DEV;
fhp->fh_handle.fh_version = version;
if (version)
fhp->fh_handle.fh_fsid_type = fsid_type;
}
__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
*
*/
struct inode * inode = dentry->d_inode;
struct dentry *parent = dentry->d_parent;
__u32 *datap;
dev_t ex_dev = exp_sb(exp)->s_dev;
dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
MAJOR(ex_dev), MINOR(ex_dev),
(long) exp->ex_path.dentry->d_inode->i_ino,
parent->d_name.name, dentry->d_name.name,
(inode ? inode->i_ino : 0));
/* Choose filehandle version and fsid type based on
* the reference filehandle (if it is in the same export)
* or the export options.
*/
set_version_and_fsid_type(fhp, exp, ref_fh);
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 (fhp->fh_handle.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_path.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_auth_type = 0;
datap = fhp->fh_handle.fh_auth+0;
mk_fsid(fhp->fh_handle.fh_fsid_type, datap, ex_dev,
exp->ex_path.dentry->d_inode->i_ino,
exp->ex_fsid, exp->ex_uuid);
len = key_len(fhp->fh_handle.fh_fsid_type);
datap += len/4;
fhp->fh_handle.fh_size = 4 + len;
if (inode)
_fh_update(fhp, exp, dentry);
if (fhp->fh_handle.fh_fileid_type == 255) {
fh_put(fhp);
return nfserr_opnotsupp;
}
}
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;
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 {
if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
goto out;
_fh_update(fhp, fhp->fh_export, dentry);
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
}
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;
}
enum fsid_source fsid_source(struct svc_fh *fhp)
{
if (fhp->fh_handle.fh_version != 1)
return FSIDSOURCE_DEV;
switch(fhp->fh_handle.fh_fsid_type) {
case FSID_DEV:
case FSID_ENCODE_DEV:
case FSID_MAJOR_MINOR:
if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
return FSIDSOURCE_DEV;
break;
case FSID_NUM:
if (fhp->fh_export->ex_flags & NFSEXP_FSID)
return FSIDSOURCE_FSID;
break;
default:
break;
}
/* either a UUID type filehandle, or the filehandle doesn't
* match the export.
*/
if (fhp->fh_export->ex_flags & NFSEXP_FSID)
return FSIDSOURCE_FSID;
if (fhp->fh_export->ex_uuid)
return FSIDSOURCE_UUID;
return FSIDSOURCE_DEV;
}
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