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| author | Theodore Ts'o <tytso@mit.edu> | 2018-08-27 07:47:09 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2018-08-27 07:47:09 +0200 |
| commit | b50282f3241acee880514212d88b6049fb5039c8 (patch) | |
| tree | b848cc5a2dce967053f7e1c63ee782e619100b07 /fs | |
| parent | ext4: add nonstring annotations to ext4.h (diff) | |
| download | linux-b50282f3241acee880514212d88b6049fb5039c8.tar.xz linux-b50282f3241acee880514212d88b6049fb5039c8.zip | |
ext4: check to make sure the rename(2)'s destination is not freed
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
Diffstat (limited to 'fs')
| -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 116ff68c5bd4..377d516c475f 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3478,6 +3478,12 @@ 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))) |