linux/fs/jfs/acl.c
William Burrow e31da3f98d JFS: Check for NULL before calling posix_acl_equiv_mode()
Check for NULL before using the acl in the access type switch
statement. This seems to be consistent with what is done in the JFFS
and ext4 filesystems and with the behaviour of JFS in the 3.13 kernel.
The bug seemed to be introduced in commit 2cc6a5a0.

The bug results in a kernel Oops, NULL dereference could not be handled
when accessing a JFS filesystem. The rdiff-backup process seemed to
trigger the bug. See also reported bug #75341:

   https://bugzilla.kernel.org/show_bug.cgi?id=75341

Signed-off-by: William Burrow <wbkernel@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2014-05-28 21:19:02 -05:00

162 lines
3.7 KiB
C

/*
* Copyright (C) International Business Machines Corp., 2002-2004
* Copyright (C) Andreas Gruenbacher, 2001
* Copyright (C) Linus Torvalds, 1991, 1992
*
* 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 02111-1307 USA
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/posix_acl_xattr.h>
#include "jfs_incore.h"
#include "jfs_txnmgr.h"
#include "jfs_xattr.h"
#include "jfs_acl.h"
struct posix_acl *jfs_get_acl(struct inode *inode, int type)
{
struct posix_acl *acl;
char *ea_name;
int size;
char *value = NULL;
acl = get_cached_acl(inode, type);
if (acl != ACL_NOT_CACHED)
return acl;
switch(type) {
case ACL_TYPE_ACCESS:
ea_name = POSIX_ACL_XATTR_ACCESS;
break;
case ACL_TYPE_DEFAULT:
ea_name = POSIX_ACL_XATTR_DEFAULT;
break;
default:
return ERR_PTR(-EINVAL);
}
size = __jfs_getxattr(inode, ea_name, NULL, 0);
if (size > 0) {
value = kmalloc(size, GFP_KERNEL);
if (!value)
return ERR_PTR(-ENOMEM);
size = __jfs_getxattr(inode, ea_name, value, size);
}
if (size < 0) {
if (size == -ENODATA)
acl = NULL;
else
acl = ERR_PTR(size);
} else {
acl = posix_acl_from_xattr(&init_user_ns, value, size);
}
kfree(value);
if (!IS_ERR(acl))
set_cached_acl(inode, type, acl);
return acl;
}
static int __jfs_set_acl(tid_t tid, struct inode *inode, int type,
struct posix_acl *acl)
{
char *ea_name;
int rc;
int size = 0;
char *value = NULL;
switch (type) {
case ACL_TYPE_ACCESS:
ea_name = POSIX_ACL_XATTR_ACCESS;
if (acl) {
rc = posix_acl_equiv_mode(acl, &inode->i_mode);
if (rc < 0)
return rc;
inode->i_ctime = CURRENT_TIME;
mark_inode_dirty(inode);
if (rc == 0)
acl = NULL;
}
break;
case ACL_TYPE_DEFAULT:
ea_name = POSIX_ACL_XATTR_DEFAULT;
break;
default:
return -EINVAL;
}
if (acl) {
size = posix_acl_xattr_size(acl->a_count);
value = kmalloc(size, GFP_KERNEL);
if (!value)
return -ENOMEM;
rc = posix_acl_to_xattr(&init_user_ns, acl, value, size);
if (rc < 0)
goto out;
}
rc = __jfs_setxattr(tid, inode, ea_name, value, size, 0);
out:
kfree(value);
if (!rc)
set_cached_acl(inode, type, acl);
return rc;
}
int jfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
int rc;
tid_t tid;
tid = txBegin(inode->i_sb, 0);
mutex_lock(&JFS_IP(inode)->commit_mutex);
rc = __jfs_set_acl(tid, inode, type, acl);
if (!rc)
rc = txCommit(tid, 1, &inode, 0);
txEnd(tid);
mutex_unlock(&JFS_IP(inode)->commit_mutex);
return rc;
}
int jfs_init_acl(tid_t tid, struct inode *inode, struct inode *dir)
{
struct posix_acl *default_acl, *acl;
int rc = 0;
rc = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
if (rc)
return rc;
if (default_acl) {
rc = __jfs_set_acl(tid, inode, ACL_TYPE_DEFAULT, default_acl);
posix_acl_release(default_acl);
}
if (acl) {
if (!rc)
rc = __jfs_set_acl(tid, inode, ACL_TYPE_ACCESS, acl);
posix_acl_release(acl);
}
JFS_IP(inode)->mode2 = (JFS_IP(inode)->mode2 & 0xffff0000) |
inode->i_mode;
return rc;
}