diff options
| author | Theodore Ts'o <tytso@mit.edu> | 2018-08-27 01:47:09 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-29 03:07:34 -0700 |
| commit | 23f57cb1f1a3bddfccddc6f7026461b2a4d9bcc7 (patch) | |
| tree | 171a3a10d58d906aea7ab1140640d8fe6879cb17 | |
| parent | 0ec459ec174031fad02a55e622cf2fc0d2e75a25 (diff) | |
ext4: check to make sure the rename(2)'s destination is not freed
commit b50282f3241acee880514212d88b6049fb5039c8 upstream.
If the destination of the rename(2) system call exists, the inode's
link count (i_nlinks) must be non-zero. If it is, the inode can end
up on the orphan list prematurely, leading to all sorts of hilarity,
including a use-after-free.
https://bugzilla.kernel.org/show_bug.cgi?id=200931
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: Wen Xu <wen.xu@gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/ext4/namei.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index a225a21d04ad..bc727c393a89 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3527,6 +3527,12 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, int credits; u8 old_file_type; + if (new.inode && new.inode->i_nlink == 0) { + EXT4_ERROR_INODE(new.inode, + "target of rename is already freed"); + return -EFSCORRUPTED; + } + if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT)) && (!projid_eq(EXT4_I(new_dir)->i_projid, EXT4_I(old_dentry->d_inode)->i_projid))) |