OpenE2K
/
linux
6
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

fat: fix uninit-memory access for partial initialized inode 

commit bc87302a09 upstream.

When get an error in the middle of reading an inode, some fields in the
inode might be still not initialized.  And then the evict_inode path may
access those fields via iput().

To fix, this makes sure that inode fields are initialized.

Reported-by: syzbot+9d82b8de2992579da5d0@syzkaller.appspotmail.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/871rqnreqx.fsf@mail.parknet.co.jp
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
OGAWA Hirofumi 2020-03-05 22:28:36 -08:00 committed by Greg Kroah-Hartman
parent d467fbc93c
commit 557693d1d3
1 changed files with 7 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
fs/fat/inode.c
View File

@ -749,6 +749,13 @@ static struct inode *fat_alloc_inode(struct super_block *sb)
return NULL;
init_rwsem(&ei->truncate_lock);
/* Zeroing to allow iput() even if partial initialized inode. */
ei->mmu_private = 0;
ei->i_start = 0;
ei->i_logstart = 0;
ei->i_attrs = 0;
ei->i_pos = 0;
return &ei->vfs_inode;
}
@ -1373,16 +1380,6 @@ out:
return 0;
}
static void fat_dummy_inode_init(struct inode *inode)
{
/* Initialize this dummy inode to work as no-op. */
MSDOS_I(inode)->mmu_private = 0;
MSDOS_I(inode)->i_start = 0;
MSDOS_I(inode)->i_logstart = 0;
MSDOS_I(inode)->i_attrs = 0;
MSDOS_I(inode)->i_pos = 0;
}
static int fat_read_root(struct inode *inode)
{
struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
@ -1843,13 +1840,11 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
fat_inode = new_inode(sb);
if (!fat_inode)
goto out_fail;
fat_dummy_inode_init(fat_inode);
sbi->fat_inode = fat_inode;
fsinfo_inode = new_inode(sb);
if (!fsinfo_inode)
goto out_fail;
fat_dummy_inode_init(fsinfo_inode);
fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
sbi->fsinfo_inode = fsinfo_inode;
insert_inode_hash(fsinfo_inode);