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linux/fs/reiserfs/xattr_acl.c
Jan Kara b9251b823b [PATCH] Fix reiserfs deadlock 
reiserfs_cache_default_acl() should return whether we successfully found
the acl or not.  We have to return correct value even if reiserfs_get_acl()
returns error code and not just 0.  Otherwise callers such as
reiserfs_mkdir() can unnecessarily lock the xattrs and later functions such
as reiserfs_new_inode() fail to notice that we have already taken the lock
and try to take it again with obvious consequences.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: <reiserfs-dev@namesys.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-22 09:19:53 -07:00

566 lines
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#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/posix_acl.h>
#include <linux/reiserfs_fs.h>
#include <linux/errno.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/reiserfs_xattr.h>
#include <linux/reiserfs_acl.h>
#include <asm/uaccess.h>
static int reiserfs_set_acl(struct inode *inode, int type,
struct posix_acl *acl);
static int
xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
{
struct posix_acl *acl;
int error;
if (!reiserfs_posixacl(inode->i_sb))
return -EOPNOTSUPP;
if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
return -EPERM;
if (value) {
acl = posix_acl_from_xattr(value, size);
if (IS_ERR(acl)) {
return PTR_ERR(acl);
} else if (acl) {
error = posix_acl_valid(acl);
if (error)
goto release_and_out;
}
} else
acl = NULL;
error = reiserfs_set_acl(inode, type, acl);
release_and_out:
posix_acl_release(acl);
return error;
}
static int
xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
{
struct posix_acl *acl;
int error;
if (!reiserfs_posixacl(inode->i_sb))
return -EOPNOTSUPP;
acl = reiserfs_get_acl(inode, type);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl == NULL)
return -ENODATA;
error = posix_acl_to_xattr(acl, buffer, size);
posix_acl_release(acl);
return error;
}
/*
* Convert from filesystem to in-memory representation.
*/
static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
{
const char *end = (char *)value + size;
int n, count;
struct posix_acl *acl;
if (!value)
return NULL;
if (size < sizeof(reiserfs_acl_header))
return ERR_PTR(-EINVAL);
if (((reiserfs_acl_header *) value)->a_version !=
cpu_to_le32(REISERFS_ACL_VERSION))
return ERR_PTR(-EINVAL);
value = (char *)value + sizeof(reiserfs_acl_header);
count = reiserfs_acl_count(size);
if (count < 0)
return ERR_PTR(-EINVAL);
if (count == 0)
return NULL;
acl = posix_acl_alloc(count, GFP_NOFS);
if (!acl)
return ERR_PTR(-ENOMEM);
for (n = 0; n < count; n++) {
reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
goto fail;
acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
switch (acl->a_entries[n].e_tag) {
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
value = (char *)value +
sizeof(reiserfs_acl_entry_short);
acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
break;
case ACL_USER:
case ACL_GROUP:
value = (char *)value + sizeof(reiserfs_acl_entry);
if ((char *)value > end)
goto fail;
acl->a_entries[n].e_id = le32_to_cpu(entry->e_id);
break;
default:
goto fail;
}
}
if (value != end)
goto fail;
return acl;
fail:
posix_acl_release(acl);
return ERR_PTR(-EINVAL);
}
/*
* Convert from in-memory to filesystem representation.
*/
static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
{
reiserfs_acl_header *ext_acl;
char *e;
int n;
*size = reiserfs_acl_size(acl->a_count);
ext_acl = (reiserfs_acl_header *) kmalloc(sizeof(reiserfs_acl_header) +
acl->a_count *
sizeof(reiserfs_acl_entry),
GFP_NOFS);
if (!ext_acl)
return ERR_PTR(-ENOMEM);
ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
e = (char *)ext_acl + sizeof(reiserfs_acl_header);
for (n = 0; n < acl->a_count; n++) {
reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
switch (acl->a_entries[n].e_tag) {
case ACL_USER:
case ACL_GROUP:
entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
e += sizeof(reiserfs_acl_entry);
break;
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
e += sizeof(reiserfs_acl_entry_short);
break;
default:
goto fail;
}
}
return (char *)ext_acl;
fail:
kfree(ext_acl);
return ERR_PTR(-EINVAL);
}
/*
* Inode operation get_posix_acl().
*
* inode->i_mutex: down
* BKL held [before 2.5.x]
*/
struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
{
char *name, *value;
struct posix_acl *acl, **p_acl;
int size;
int retval;
struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
switch (type) {
case ACL_TYPE_ACCESS:
name = POSIX_ACL_XATTR_ACCESS;
p_acl = &reiserfs_i->i_acl_access;
break;
case ACL_TYPE_DEFAULT:
name = POSIX_ACL_XATTR_DEFAULT;
p_acl = &reiserfs_i->i_acl_default;
break;
default:
return ERR_PTR(-EINVAL);
}
if (IS_ERR(*p_acl)) {
if (PTR_ERR(*p_acl) == -ENODATA)
return NULL;
} else if (*p_acl != NULL)
return posix_acl_dup(*p_acl);
size = reiserfs_xattr_get(inode, name, NULL, 0);
if (size < 0) {
if (size == -ENODATA || size == -ENOSYS) {
*p_acl = ERR_PTR(-ENODATA);
return NULL;
}
return ERR_PTR(size);
}
value = kmalloc(size, GFP_NOFS);
if (!value)
return ERR_PTR(-ENOMEM);
retval = reiserfs_xattr_get(inode, name, value, size);
if (retval == -ENODATA || retval == -ENOSYS) {
/* This shouldn't actually happen as it should have
been caught above.. but just in case */
acl = NULL;
*p_acl = ERR_PTR(-ENODATA);
} else if (retval < 0) {
acl = ERR_PTR(retval);
} else {
acl = posix_acl_from_disk(value, retval);
if (!IS_ERR(acl))
*p_acl = posix_acl_dup(acl);
}
kfree(value);
return acl;
}
/*
* Inode operation set_posix_acl().
*
* inode->i_mutex: down
* BKL held [before 2.5.x]
*/
static int
reiserfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
char *name;
void *value = NULL;
struct posix_acl **p_acl;
size_t size;
int error;
struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
switch (type) {
case ACL_TYPE_ACCESS:
name = POSIX_ACL_XATTR_ACCESS;
p_acl = &reiserfs_i->i_acl_access;
if (acl) {
mode_t mode = inode->i_mode;
error = posix_acl_equiv_mode(acl, &mode);
if (error < 0)
return error;
else {
inode->i_mode = mode;
if (error == 0)
acl = NULL;
}
}
break;
case ACL_TYPE_DEFAULT:
name = POSIX_ACL_XATTR_DEFAULT;
p_acl = &reiserfs_i->i_acl_default;
if (!S_ISDIR(inode->i_mode))
return acl ? -EACCES : 0;
break;
default:
return -EINVAL;
}
if (acl) {
value = posix_acl_to_disk(acl, &size);
if (IS_ERR(value))
return (int)PTR_ERR(value);
error = reiserfs_xattr_set(inode, name, value, size, 0);
} else {
error = reiserfs_xattr_del(inode, name);
if (error == -ENODATA) {
/* This may seem odd here, but it means that the ACL was set
* with a value representable with mode bits. If there was
* an ACL before, reiserfs_xattr_del already dirtied the inode.
*/
mark_inode_dirty(inode);
error = 0;
}
}
kfree(value);
if (!error) {
/* Release the old one */
if (!IS_ERR(*p_acl) && *p_acl)
posix_acl_release(*p_acl);
if (acl == NULL)
*p_acl = ERR_PTR(-ENODATA);
else
*p_acl = posix_acl_dup(acl);
}
return error;
}
/* dir->i_mutex: locked,
* inode is new and not released into the wild yet */
int
reiserfs_inherit_default_acl(struct inode *dir, struct dentry *dentry,
struct inode *inode)
{
struct posix_acl *acl;
int err = 0;
/* ACLs only get applied to files and directories */
if (S_ISLNK(inode->i_mode))
return 0;
/* ACLs can only be used on "new" objects, so if it's an old object
* there is nothing to inherit from */
if (get_inode_sd_version(dir) == STAT_DATA_V1)
goto apply_umask;
/* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
* would be useless since permissions are ignored, and a pain because
* it introduces locking cycles */
if (is_reiserfs_priv_object(dir)) {
reiserfs_mark_inode_private(inode);
goto apply_umask;
}
acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
if (IS_ERR(acl)) {
if (PTR_ERR(acl) == -ENODATA)
goto apply_umask;
return PTR_ERR(acl);
}
if (acl) {
struct posix_acl *acl_copy;
mode_t mode = inode->i_mode;
int need_acl;
/* Copy the default ACL to the default ACL of a new directory */
if (S_ISDIR(inode->i_mode)) {
err = reiserfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
if (err)
goto cleanup;
}
/* Now we reconcile the new ACL and the mode,
potentially modifying both */
acl_copy = posix_acl_clone(acl, GFP_NOFS);
if (!acl_copy) {
err = -ENOMEM;
goto cleanup;
}
need_acl = posix_acl_create_masq(acl_copy, &mode);
if (need_acl >= 0) {
if (mode != inode->i_mode) {
inode->i_mode = mode;
}
/* If we need an ACL.. */
if (need_acl > 0) {
err =
reiserfs_set_acl(inode, ACL_TYPE_ACCESS,
acl_copy);
if (err)
goto cleanup_copy;
}
}
cleanup_copy:
posix_acl_release(acl_copy);
cleanup:
posix_acl_release(acl);
} else {
apply_umask:
/* no ACL, apply umask */
inode->i_mode &= ~current->fs->umask;
}
return err;
}
/* Looks up and caches the result of the default ACL.
* We do this so that we don't need to carry the xattr_sem into
* reiserfs_new_inode if we don't need to */
int reiserfs_cache_default_acl(struct inode *inode)
{
int ret = 0;
if (reiserfs_posixacl(inode->i_sb) && !is_reiserfs_priv_object(inode)) {
struct posix_acl *acl;
reiserfs_read_lock_xattr_i(inode);
reiserfs_read_lock_xattrs(inode->i_sb);
acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
reiserfs_read_unlock_xattrs(inode->i_sb);
reiserfs_read_unlock_xattr_i(inode);
ret = (acl && !IS_ERR(acl));
if (ret)
posix_acl_release(acl);
}
return ret;
}
int reiserfs_acl_chmod(struct inode *inode)
{
struct posix_acl *acl, *clone;
int error;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
!reiserfs_posixacl(inode->i_sb)) {
return 0;
}
reiserfs_read_lock_xattrs(inode->i_sb);
acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
reiserfs_read_unlock_xattrs(inode->i_sb);
if (!acl)
return 0;
if (IS_ERR(acl))
return PTR_ERR(acl);
clone = posix_acl_clone(acl, GFP_NOFS);
posix_acl_release(acl);
if (!clone)
return -ENOMEM;
error = posix_acl_chmod_masq(clone, inode->i_mode);
if (!error) {
int lock = !has_xattr_dir(inode);
reiserfs_write_lock_xattr_i(inode);
if (lock)
reiserfs_write_lock_xattrs(inode->i_sb);
else
reiserfs_read_lock_xattrs(inode->i_sb);
error = reiserfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
if (lock)
reiserfs_write_unlock_xattrs(inode->i_sb);
else
reiserfs_read_unlock_xattrs(inode->i_sb);
reiserfs_write_unlock_xattr_i(inode);
}
posix_acl_release(clone);
return error;
}
static int
posix_acl_access_get(struct inode *inode, const char *name,
void *buffer, size_t size)
{
if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
return -EINVAL;
return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
}
static int
posix_acl_access_set(struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
return -EINVAL;
return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
}
static int posix_acl_access_del(struct inode *inode, const char *name)
{
struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
struct posix_acl **acl = &reiserfs_i->i_acl_access;
if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
return -EINVAL;
if (!IS_ERR(*acl) && *acl) {
posix_acl_release(*acl);
*acl = ERR_PTR(-ENODATA);
}
return 0;
}
static int
posix_acl_access_list(struct inode *inode, const char *name, int namelen,
char *out)
{
int len = namelen;
if (!reiserfs_posixacl(inode->i_sb))
return 0;
if (out)
memcpy(out, name, len);
return len;
}
struct reiserfs_xattr_handler posix_acl_access_handler = {
.prefix = POSIX_ACL_XATTR_ACCESS,
.get = posix_acl_access_get,
.set = posix_acl_access_set,
.del = posix_acl_access_del,
.list = posix_acl_access_list,
};
static int
posix_acl_default_get(struct inode *inode, const char *name,
void *buffer, size_t size)
{
if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
return -EINVAL;
return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
}
static int
posix_acl_default_set(struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
return -EINVAL;
return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
}
static int posix_acl_default_del(struct inode *inode, const char *name)
{
struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
struct posix_acl **acl = &reiserfs_i->i_acl_default;
if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
return -EINVAL;
if (!IS_ERR(*acl) && *acl) {
posix_acl_release(*acl);
*acl = ERR_PTR(-ENODATA);
}
return 0;
}
static int
posix_acl_default_list(struct inode *inode, const char *name, int namelen,
char *out)
{
int len = namelen;
if (!reiserfs_posixacl(inode->i_sb))
return 0;
if (out)
memcpy(out, name, len);
return len;
}
struct reiserfs_xattr_handler posix_acl_default_handler = {
.prefix = POSIX_ACL_XATTR_DEFAULT,
.get = posix_acl_default_get,
.set = posix_acl_default_set,
.del = posix_acl_default_del,
.list = posix_acl_default_list,
};
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