linux/fs/reiserfs/xattr.h
Tetsuo Handa 5e46d1b78a reiserfs: update reiserfs_xattrs_initialized() condition
syzbot is reporting NULL pointer dereference at reiserfs_security_init()
[1], for commit ab17c4f021 ("reiserfs: fixup xattr_root caching")
is assuming that REISERFS_SB(s)->xattr_root != NULL in
reiserfs_xattr_jcreate_nblocks() despite that commit made
REISERFS_SB(sb)->priv_root != NULL && REISERFS_SB(s)->xattr_root == NULL
case possible.

I guess that commit 6cb4aff0a7 ("reiserfs: fix oops while creating
privroot with selinux enabled") wanted to check xattr_root != NULL
before reiserfs_xattr_jcreate_nblocks(), for the changelog is talking
about the xattr root.

  The issue is that while creating the privroot during mount
  reiserfs_security_init calls reiserfs_xattr_jcreate_nblocks which
  dereferences the xattr root. The xattr root doesn't exist, so we get
  an oops.

Therefore, update reiserfs_xattrs_initialized() to check both the
privroot and the xattr root.

Link: https://syzkaller.appspot.com/bug?id=8abaedbdeb32c861dc5340544284167dd0e46cde # [1]
Reported-and-tested-by: syzbot <syzbot+690cb1e51970435f9775@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Fixes: 6cb4aff0a7 ("reiserfs: fix oops while creating privroot with selinux enabled")
Acked-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Jan Kara <jack@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-03-30 14:27:32 -07:00

118 lines
3.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/reiserfs_xattr.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/rwsem.h>
#include <linux/xattr.h>
struct inode;
struct dentry;
struct iattr;
struct super_block;
int reiserfs_xattr_register_handlers(void) __init;
void reiserfs_xattr_unregister_handlers(void);
int reiserfs_xattr_init(struct super_block *sb, int mount_flags);
int reiserfs_lookup_privroot(struct super_block *sb);
int reiserfs_delete_xattrs(struct inode *inode);
int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs);
int reiserfs_permission(struct user_namespace *mnt_userns,
struct inode *inode, int mask);
#ifdef CONFIG_REISERFS_FS_XATTR
#define has_xattr_dir(inode) (REISERFS_I(inode)->i_flags & i_has_xattr_dir)
ssize_t reiserfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
int reiserfs_xattr_get(struct inode *, const char *, void *, size_t);
int reiserfs_xattr_set(struct inode *, const char *, const void *, size_t, int);
int reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *,
struct inode *, const char *, const void *,
size_t, int);
extern const struct xattr_handler reiserfs_xattr_user_handler;
extern const struct xattr_handler reiserfs_xattr_trusted_handler;
extern const struct xattr_handler reiserfs_xattr_security_handler;
#ifdef CONFIG_REISERFS_FS_SECURITY
int reiserfs_security_init(struct inode *dir, struct inode *inode,
const struct qstr *qstr,
struct reiserfs_security_handle *sec);
int reiserfs_security_write(struct reiserfs_transaction_handle *th,
struct inode *inode,
struct reiserfs_security_handle *sec);
void reiserfs_security_free(struct reiserfs_security_handle *sec);
#endif
static inline int reiserfs_xattrs_initialized(struct super_block *sb)
{
return REISERFS_SB(sb)->priv_root && REISERFS_SB(sb)->xattr_root;
}
#define xattr_size(size) ((size) + sizeof(struct reiserfs_xattr_header))
static inline loff_t reiserfs_xattr_nblocks(struct inode *inode, loff_t size)
{
loff_t ret = 0;
if (reiserfs_file_data_log(inode)) {
ret = _ROUND_UP(xattr_size(size), inode->i_sb->s_blocksize);
ret >>= inode->i_sb->s_blocksize_bits;
}
return ret;
}
/*
* We may have to create up to 3 objects: xattr root, xattr dir, xattr file.
* Let's try to be smart about it.
* xattr root: We cache it. If it's not cached, we may need to create it.
* xattr dir: If anything has been loaded for this inode, we can set a flag
* saying so.
* xattr file: Since we don't cache xattrs, we can't tell. We always include
* blocks for it.
*
* However, since root and dir can be created between calls - YOU MUST SAVE
* THIS VALUE.
*/
static inline size_t reiserfs_xattr_jcreate_nblocks(struct inode *inode)
{
size_t nblocks = JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
if ((REISERFS_I(inode)->i_flags & i_has_xattr_dir) == 0) {
nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
if (d_really_is_negative(REISERFS_SB(inode->i_sb)->xattr_root))
nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
}
return nblocks;
}
static inline void reiserfs_init_xattr_rwsem(struct inode *inode)
{
init_rwsem(&REISERFS_I(inode)->i_xattr_sem);
}
#else
#define reiserfs_listxattr NULL
static inline void reiserfs_init_xattr_rwsem(struct inode *inode)
{
}
#endif /* CONFIG_REISERFS_FS_XATTR */
#ifndef CONFIG_REISERFS_FS_SECURITY
static inline int reiserfs_security_init(struct inode *dir,
struct inode *inode,
const struct qstr *qstr,
struct reiserfs_security_handle *sec)
{
return 0;
}
static inline int
reiserfs_security_write(struct reiserfs_transaction_handle *th,
struct inode *inode,
struct reiserfs_security_handle *sec)
{
return 0;
}
static inline void reiserfs_security_free(struct reiserfs_security_handle *sec)
{}
#endif