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alistair23-linux/fs/hfsplus/dir.c
Christoph Hellwig f6089ff87d hfsplus: fix link corruption 
HFS implements hardlink by using indirect catalog entries that refer to a hidden
directly.  The link target is cached in the dev field in the HFS+ specific
inode, which is also used for the device number for device files, and inside
for passing the nlink value of the indirect node from hfsplus_cat_write_inode
to a helper function.  Now if we happen to write out the indirect node while
hfsplus_link is creating the catalog entry we'll get a link pointing to the
linkid of the current nlink value.  This can easily be reproduced by a large
enough loop of local git-clone operations.

Stop abusing the dev field in the HFS+ inode for short term storage by
refactoring the way the permission structure in the catalog entry is
set up, and rename the dev field to linkid to avoid any confusion.

While we're at it also prevent creating hard links to special files, as
the HFS+ dev and linkid share the same space in the on-disk structure.

Signed-off-by: Christoph Hellwig <hch@tuxera.com>
2010-10-14 09:54:28 -04:00

492 lines
12 KiB
C
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/*
* linux/fs/hfsplus/dir.c
*
* Copyright (C) 2001
* Brad Boyer (flar@allandria.com)
* (C) 2003 Ardis Technologies <roman@ardistech.com>
*
* Handling of directories
*/
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/random.h>
#include "hfsplus_fs.h"
#include "hfsplus_raw.h"
static inline void hfsplus_instantiate(struct dentry *dentry,
struct inode *inode, u32 cnid)
{
dentry->d_fsdata = (void *)(unsigned long)cnid;
d_instantiate(dentry, inode);
}
/* Find the entry inside dir named dentry->d_name */
static struct dentry *hfsplus_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
struct inode *inode = NULL;
struct hfs_find_data fd;
struct super_block *sb;
hfsplus_cat_entry entry;
int err;
u32 cnid, linkid = 0;
u16 type;
sb = dir->i_sb;
dentry->d_op = &hfsplus_dentry_operations;
dentry->d_fsdata = NULL;
hfs_find_init(HFSPLUS_SB(sb)->cat_tree, &fd);
hfsplus_cat_build_key(sb, fd.search_key, dir->i_ino, &dentry->d_name);
again:
err = hfs_brec_read(&fd, &entry, sizeof(entry));
if (err) {
if (err == -ENOENT) {
hfs_find_exit(&fd);
/* No such entry */
inode = NULL;
goto out;
}
goto fail;
}
type = be16_to_cpu(entry.type);
if (type == HFSPLUS_FOLDER) {
if (fd.entrylength < sizeof(struct hfsplus_cat_folder)) {
err = -EIO;
goto fail;
}
cnid = be32_to_cpu(entry.folder.id);
dentry->d_fsdata = (void *)(unsigned long)cnid;
} else if (type == HFSPLUS_FILE) {
if (fd.entrylength < sizeof(struct hfsplus_cat_file)) {
err = -EIO;
goto fail;
}
cnid = be32_to_cpu(entry.file.id);
if (entry.file.user_info.fdType == cpu_to_be32(HFSP_HARDLINK_TYPE) &&
entry.file.user_info.fdCreator == cpu_to_be32(HFSP_HFSPLUS_CREATOR) &&
(entry.file.create_date == HFSPLUS_I(HFSPLUS_SB(sb)->hidden_dir)->create_date ||
entry.file.create_date == HFSPLUS_I(sb->s_root->d_inode)->create_date) &&
HFSPLUS_SB(sb)->hidden_dir) {
struct qstr str;
char name[32];
if (dentry->d_fsdata) {
/*
* We found a link pointing to another link,
* so ignore it and treat it as regular file.
*/
cnid = (unsigned long)dentry->d_fsdata;
linkid = 0;
} else {
dentry->d_fsdata = (void *)(unsigned long)cnid;
linkid = be32_to_cpu(entry.file.permissions.dev);
str.len = sprintf(name, "iNode%d", linkid);
str.name = name;
hfsplus_cat_build_key(sb, fd.search_key,
HFSPLUS_SB(sb)->hidden_dir->i_ino, &str);
goto again;
}
} else if (!dentry->d_fsdata)
dentry->d_fsdata = (void *)(unsigned long)cnid;
} else {
printk(KERN_ERR "hfs: invalid catalog entry type in lookup\n");
err = -EIO;
goto fail;
}
hfs_find_exit(&fd);
inode = hfsplus_iget(dir->i_sb, cnid);
if (IS_ERR(inode))
return ERR_CAST(inode);
if (S_ISREG(inode->i_mode))
HFSPLUS_I(inode)->linkid = linkid;
out:
d_add(dentry, inode);
return NULL;
fail:
hfs_find_exit(&fd);
return ERR_PTR(err);
}
static int hfsplus_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct inode *inode = filp->f_path.dentry->d_inode;
struct super_block *sb = inode->i_sb;
int len, err;
char strbuf[HFSPLUS_MAX_STRLEN + 1];
hfsplus_cat_entry entry;
struct hfs_find_data fd;
struct hfsplus_readdir_data *rd;
u16 type;
if (filp->f_pos >= inode->i_size)
return 0;
hfs_find_init(HFSPLUS_SB(sb)->cat_tree, &fd);
hfsplus_cat_build_key(sb, fd.search_key, inode->i_ino, NULL);
err = hfs_brec_find(&fd);
if (err)
goto out;
switch ((u32)filp->f_pos) {
case 0:
/* This is completely artificial... */
if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR))
goto out;
filp->f_pos++;
/* fall through */
case 1:
hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);
if (be16_to_cpu(entry.type) != HFSPLUS_FOLDER_THREAD) {
printk(KERN_ERR "hfs: bad catalog folder thread\n");
err = -EIO;
goto out;
}
if (fd.entrylength < HFSPLUS_MIN_THREAD_SZ) {
printk(KERN_ERR "hfs: truncated catalog thread\n");
err = -EIO;
goto out;
}
if (filldir(dirent, "..", 2, 1,
be32_to_cpu(entry.thread.parentID), DT_DIR))
goto out;
filp->f_pos++;
/* fall through */
default:
if (filp->f_pos >= inode->i_size)
goto out;
err = hfs_brec_goto(&fd, filp->f_pos - 1);
if (err)
goto out;
}
for (;;) {
if (be32_to_cpu(fd.key->cat.parent) != inode->i_ino) {
printk(KERN_ERR "hfs: walked past end of dir\n");
err = -EIO;
goto out;
}
hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);
type = be16_to_cpu(entry.type);
len = HFSPLUS_MAX_STRLEN;
err = hfsplus_uni2asc(sb, &fd.key->cat.name, strbuf, &len);
if (err)
goto out;
if (type == HFSPLUS_FOLDER) {
if (fd.entrylength < sizeof(struct hfsplus_cat_folder)) {
printk(KERN_ERR "hfs: small dir entry\n");
err = -EIO;
goto out;
}
if (HFSPLUS_SB(sb)->hidden_dir &&
HFSPLUS_SB(sb)->hidden_dir->i_ino ==
be32_to_cpu(entry.folder.id))
goto next;
if (filldir(dirent, strbuf, len, filp->f_pos,
be32_to_cpu(entry.folder.id), DT_DIR))
break;
} else if (type == HFSPLUS_FILE) {
if (fd.entrylength < sizeof(struct hfsplus_cat_file)) {
printk(KERN_ERR "hfs: small file entry\n");
err = -EIO;
goto out;
}
if (filldir(dirent, strbuf, len, filp->f_pos,
be32_to_cpu(entry.file.id), DT_REG))
break;
} else {
printk(KERN_ERR "hfs: bad catalog entry type\n");
err = -EIO;
goto out;
}
next:
filp->f_pos++;
if (filp->f_pos >= inode->i_size)
goto out;
err = hfs_brec_goto(&fd, 1);
if (err)
goto out;
}
rd = filp->private_data;
if (!rd) {
rd = kmalloc(sizeof(struct hfsplus_readdir_data), GFP_KERNEL);
if (!rd) {
err = -ENOMEM;
goto out;
}
filp->private_data = rd;
rd->file = filp;
list_add(&rd->list, &HFSPLUS_I(inode)->open_dir_list);
}
memcpy(&rd->key, fd.key, sizeof(struct hfsplus_cat_key));
out:
hfs_find_exit(&fd);
return err;
}
static int hfsplus_dir_release(struct inode *inode, struct file *file)
{
struct hfsplus_readdir_data *rd = file->private_data;
if (rd) {
mutex_lock(&inode->i_mutex);
list_del(&rd->list);
mutex_unlock(&inode->i_mutex);
kfree(rd);
}
return 0;
}
static int hfsplus_link(struct dentry *src_dentry, struct inode *dst_dir,
struct dentry *dst_dentry)
{
struct hfsplus_sb_info *sbi = HFSPLUS_SB(dst_dir->i_sb);
struct inode *inode = src_dentry->d_inode;
struct inode *src_dir = src_dentry->d_parent->d_inode;
struct qstr str;
char name[32];
u32 cnid, id;
int res;
if (HFSPLUS_IS_RSRC(inode))
return -EPERM;
if (!S_ISREG(inode->i_mode))
return -EPERM;
mutex_lock(&sbi->vh_mutex);
if (inode->i_ino == (u32)(unsigned long)src_dentry->d_fsdata) {
for (;;) {
get_random_bytes(&id, sizeof(cnid));
id &= 0x3fffffff;
str.name = name;
str.len = sprintf(name, "iNode%d", id);
res = hfsplus_rename_cat(inode->i_ino,
src_dir, &src_dentry->d_name,
sbi->hidden_dir, &str);
if (!res)
break;
if (res != -EEXIST)
goto out;
}
HFSPLUS_I(inode)->linkid = id;
cnid = sbi->next_cnid++;
src_dentry->d_fsdata = (void *)(unsigned long)cnid;
res = hfsplus_create_cat(cnid, src_dir, &src_dentry->d_name, inode);
if (res)
/* panic? */
goto out;
sbi->file_count++;
}
cnid = sbi->next_cnid++;
res = hfsplus_create_cat(cnid, dst_dir, &dst_dentry->d_name, inode);
if (res)
goto out;
inc_nlink(inode);
hfsplus_instantiate(dst_dentry, inode, cnid);
atomic_inc(&inode->i_count);
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
sbi->file_count++;
dst_dir->i_sb->s_dirt = 1;
out:
mutex_unlock(&sbi->vh_mutex);
return res;
}
static int hfsplus_unlink(struct inode *dir, struct dentry *dentry)
{
struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
struct inode *inode = dentry->d_inode;
struct qstr str;
char name[32];
u32 cnid;
int res;
if (HFSPLUS_IS_RSRC(inode))
return -EPERM;
mutex_lock(&sbi->vh_mutex);
cnid = (u32)(unsigned long)dentry->d_fsdata;
if (inode->i_ino == cnid &&
atomic_read(&HFSPLUS_I(inode)->opencnt)) {
str.name = name;
str.len = sprintf(name, "temp%lu", inode->i_ino);
res = hfsplus_rename_cat(inode->i_ino,
dir, &dentry->d_name,
sbi->hidden_dir, &str);
if (!res)
inode->i_flags |= S_DEAD;
goto out;
}
res = hfsplus_delete_cat(cnid, dir, &dentry->d_name);
if (res)
goto out;
if (inode->i_nlink > 0)
drop_nlink(inode);
if (inode->i_ino == cnid)
clear_nlink(inode);
if (!inode->i_nlink) {
if (inode->i_ino != cnid) {
sbi->file_count--;
if (!atomic_read(&HFSPLUS_I(inode)->opencnt)) {
res = hfsplus_delete_cat(inode->i_ino,
sbi->hidden_dir,
NULL);
if (!res)
hfsplus_delete_inode(inode);
} else
inode->i_flags |= S_DEAD;
} else
hfsplus_delete_inode(inode);
} else
sbi->file_count--;
inode->i_ctime = CURRENT_TIME_SEC;
mark_inode_dirty(inode);
out:
mutex_unlock(&sbi->vh_mutex);
return res;
}
static int hfsplus_rmdir(struct inode *dir, struct dentry *dentry)
{
struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
struct inode *inode = dentry->d_inode;
int res;
if (inode->i_size != 2)
return -ENOTEMPTY;
mutex_lock(&sbi->vh_mutex);
res = hfsplus_delete_cat(inode->i_ino, dir, &dentry->d_name);
if (res)
goto out;
clear_nlink(inode);
inode->i_ctime = CURRENT_TIME_SEC;
hfsplus_delete_inode(inode);
mark_inode_dirty(inode);
out:
mutex_unlock(&sbi->vh_mutex);
return res;
}
static int hfsplus_symlink(struct inode *dir, struct dentry *dentry,
const char *symname)
{
struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
struct inode *inode;
int res = -ENOSPC;
mutex_lock(&sbi->vh_mutex);
inode = hfsplus_new_inode(dir->i_sb, S_IFLNK | S_IRWXUGO);
if (!inode)
goto out;
res = page_symlink(inode, symname, strlen(symname) + 1);
if (res)
goto out_err;
res = hfsplus_create_cat(inode->i_ino, dir, &dentry->d_name, inode);
if (res)
goto out_err;
hfsplus_instantiate(dentry, inode, inode->i_ino);
mark_inode_dirty(inode);
goto out;
out_err:
inode->i_nlink = 0;
hfsplus_delete_inode(inode);
iput(inode);
out:
mutex_unlock(&sbi->vh_mutex);
return res;
}
static int hfsplus_mknod(struct inode *dir, struct dentry *dentry,
int mode, dev_t rdev)
{
struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
struct inode *inode;
int res = -ENOSPC;
mutex_lock(&sbi->vh_mutex);
inode = hfsplus_new_inode(dir->i_sb, mode);
if (!inode)
goto out;
res = hfsplus_create_cat(inode->i_ino, dir, &dentry->d_name, inode);
if (res) {
inode->i_nlink = 0;
hfsplus_delete_inode(inode);
iput(inode);
goto out;
}
if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode))
init_special_inode(inode, mode, rdev);
hfsplus_instantiate(dentry, inode, inode->i_ino);
mark_inode_dirty(inode);
out:
mutex_unlock(&sbi->vh_mutex);
return res;
}
static int hfsplus_create(struct inode *dir, struct dentry *dentry, int mode,
struct nameidata *nd)
{
return hfsplus_mknod(dir, dentry, mode, 0);
}
static int hfsplus_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
return hfsplus_mknod(dir, dentry, mode | S_IFDIR, 0);
}
static int hfsplus_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry)
{
int res;
/* Unlink destination if it already exists */
if (new_dentry->d_inode) {
if (S_ISDIR(new_dentry->d_inode->i_mode))
res = hfsplus_rmdir(new_dir, new_dentry);
else
res = hfsplus_unlink(new_dir, new_dentry);
if (res)
return res;
}
res = hfsplus_rename_cat((u32)(unsigned long)old_dentry->d_fsdata,
old_dir, &old_dentry->d_name,
new_dir, &new_dentry->d_name);
if (!res)
new_dentry->d_fsdata = old_dentry->d_fsdata;
return res;
}
const struct inode_operations hfsplus_dir_inode_operations = {
.lookup = hfsplus_lookup,
.create = hfsplus_create,
.link = hfsplus_link,
.unlink = hfsplus_unlink,
.mkdir = hfsplus_mkdir,
.rmdir = hfsplus_rmdir,
.symlink = hfsplus_symlink,
.mknod = hfsplus_mknod,
.rename = hfsplus_rename,
};
const struct file_operations hfsplus_dir_operations = {
.read = generic_read_dir,
.readdir = hfsplus_readdir,
.unlocked_ioctl = hfsplus_ioctl,
.llseek = generic_file_llseek,
.release = hfsplus_dir_release,
};
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