linux/fs/ocfs2/export.c
Kees Cook 7585d12f65 ocfs2: Use ERR_CAST() to avoid cross-structure cast
When trying to propagate an error result, the error return path attempts
to retain the error, but does this with an open cast across very different
types, which the upcoming structure layout randomization plugin flags as
being potentially dangerous in the face of randomization. This is a false
positive, but what this code actually wants to do is use ERR_CAST() to
retain the error value.

Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
2017-05-28 10:11:49 -07:00

272 lines
6.2 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* export.c
*
* Functions to facilitate NFS exporting
*
* Copyright (C) 2002, 2005 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/fs.h>
#include <linux/types.h>
#include <cluster/masklog.h>
#include "ocfs2.h"
#include "alloc.h"
#include "dir.h"
#include "dlmglue.h"
#include "dcache.h"
#include "export.h"
#include "inode.h"
#include "buffer_head_io.h"
#include "suballoc.h"
#include "ocfs2_trace.h"
struct ocfs2_inode_handle
{
u64 ih_blkno;
u32 ih_generation;
};
static struct dentry *ocfs2_get_dentry(struct super_block *sb,
struct ocfs2_inode_handle *handle)
{
struct inode *inode;
struct ocfs2_super *osb = OCFS2_SB(sb);
u64 blkno = handle->ih_blkno;
int status, set;
struct dentry *result;
trace_ocfs2_get_dentry_begin(sb, handle, (unsigned long long)blkno);
if (blkno == 0) {
result = ERR_PTR(-ESTALE);
goto bail;
}
inode = ocfs2_ilookup(sb, blkno);
/*
* If the inode exists in memory, we only need to check it's
* generation number
*/
if (inode)
goto check_gen;
/*
* This will synchronize us against ocfs2_delete_inode() on
* all nodes
*/
status = ocfs2_nfs_sync_lock(osb, 1);
if (status < 0) {
mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
goto check_err;
}
status = ocfs2_test_inode_bit(osb, blkno, &set);
if (status < 0) {
if (status == -EINVAL) {
/*
* The blkno NFS gave us doesn't even show up
* as an inode, we return -ESTALE to be
* nice
*/
status = -ESTALE;
} else
mlog(ML_ERROR, "test inode bit failed %d\n", status);
goto unlock_nfs_sync;
}
trace_ocfs2_get_dentry_test_bit(status, set);
/* If the inode allocator bit is clear, this inode must be stale */
if (!set) {
status = -ESTALE;
goto unlock_nfs_sync;
}
inode = ocfs2_iget(osb, blkno, 0, 0);
unlock_nfs_sync:
ocfs2_nfs_sync_unlock(osb, 1);
check_err:
if (status < 0) {
if (status == -ESTALE) {
trace_ocfs2_get_dentry_stale((unsigned long long)blkno,
handle->ih_generation);
}
result = ERR_PTR(status);
goto bail;
}
if (IS_ERR(inode)) {
mlog_errno(PTR_ERR(inode));
result = ERR_CAST(inode);
goto bail;
}
check_gen:
if (handle->ih_generation != inode->i_generation) {
iput(inode);
trace_ocfs2_get_dentry_generation((unsigned long long)blkno,
handle->ih_generation,
inode->i_generation);
result = ERR_PTR(-ESTALE);
goto bail;
}
result = d_obtain_alias(inode);
if (IS_ERR(result))
mlog_errno(PTR_ERR(result));
bail:
trace_ocfs2_get_dentry_end(result);
return result;
}
static struct dentry *ocfs2_get_parent(struct dentry *child)
{
int status;
u64 blkno;
struct dentry *parent;
struct inode *dir = d_inode(child);
trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
(unsigned long long)OCFS2_I(dir)->ip_blkno);
status = ocfs2_inode_lock(dir, NULL, 0);
if (status < 0) {
if (status != -ENOENT)
mlog_errno(status);
parent = ERR_PTR(status);
goto bail;
}
status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
if (status < 0) {
parent = ERR_PTR(-ENOENT);
goto bail_unlock;
}
parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
bail_unlock:
ocfs2_inode_unlock(dir, 0);
bail:
trace_ocfs2_get_parent_end(parent);
return parent;
}
static int ocfs2_encode_fh(struct inode *inode, u32 *fh_in, int *max_len,
struct inode *parent)
{
int len = *max_len;
int type = 1;
u64 blkno;
u32 generation;
__le32 *fh = (__force __le32 *) fh_in;
#ifdef TRACE_HOOKS_ARE_NOT_BRAINDEAD_IN_YOUR_OPINION
#error "You go ahead and fix that mess, then. Somehow"
trace_ocfs2_encode_fh_begin(dentry, dentry->d_name.len,
dentry->d_name.name,
fh, len, connectable);
#endif
if (parent && (len < 6)) {
*max_len = 6;
type = FILEID_INVALID;
goto bail;
} else if (len < 3) {
*max_len = 3;
type = FILEID_INVALID;
goto bail;
}
blkno = OCFS2_I(inode)->ip_blkno;
generation = inode->i_generation;
trace_ocfs2_encode_fh_self((unsigned long long)blkno, generation);
len = 3;
fh[0] = cpu_to_le32((u32)(blkno >> 32));
fh[1] = cpu_to_le32((u32)(blkno & 0xffffffff));
fh[2] = cpu_to_le32(generation);
if (parent) {
blkno = OCFS2_I(parent)->ip_blkno;
generation = parent->i_generation;
fh[3] = cpu_to_le32((u32)(blkno >> 32));
fh[4] = cpu_to_le32((u32)(blkno & 0xffffffff));
fh[5] = cpu_to_le32(generation);
len = 6;
type = 2;
trace_ocfs2_encode_fh_parent((unsigned long long)blkno,
generation);
}
*max_len = len;
bail:
trace_ocfs2_encode_fh_type(type);
return type;
}
static struct dentry *ocfs2_fh_to_dentry(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
struct ocfs2_inode_handle handle;
if (fh_len < 3 || fh_type > 2)
return NULL;
handle.ih_blkno = (u64)le32_to_cpu(fid->raw[0]) << 32;
handle.ih_blkno |= (u64)le32_to_cpu(fid->raw[1]);
handle.ih_generation = le32_to_cpu(fid->raw[2]);
return ocfs2_get_dentry(sb, &handle);
}
static struct dentry *ocfs2_fh_to_parent(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
struct ocfs2_inode_handle parent;
if (fh_type != 2 || fh_len < 6)
return NULL;
parent.ih_blkno = (u64)le32_to_cpu(fid->raw[3]) << 32;
parent.ih_blkno |= (u64)le32_to_cpu(fid->raw[4]);
parent.ih_generation = le32_to_cpu(fid->raw[5]);
return ocfs2_get_dentry(sb, &parent);
}
const struct export_operations ocfs2_export_ops = {
.encode_fh = ocfs2_encode_fh,
.fh_to_dentry = ocfs2_fh_to_dentry,
.fh_to_parent = ocfs2_fh_to_parent,
.get_parent = ocfs2_get_parent,
};