Messages in this thread Patch in this message | | | Date | Fri, 08 Jun 2012 05:19:18 +0100 | From | Ben Hutchings <> | Subject | [ 38/82] ext4: disallow hard-linked directory in ext4_lookup |
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3.2-stable review patch. If anyone has any objections, please let me know.
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From: Andreas Dilger <adilger@dilger.ca>
commit 7e936b737211e6b54e34b71a827e56b872e958d8 upstream.
A hard-linked directory to its parent can cause the VFS to deadlock, and is a sign of a corrupted file system. So detect this case in ext4_lookup(), before the rmdir() lockup scenario can take place.
Signed-off-by: Andreas Dilger <adilger@dilger.ca> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- fs/ext4/namei.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index a9fd5f4..daf8260 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1330,6 +1330,12 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, stru EXT4_ERROR_INODE(dir, "bad inode number: %u", ino); return ERR_PTR(-EIO); } + if (unlikely(ino == dir->i_ino)) { + EXT4_ERROR_INODE(dir, "'%.*s' linked to parent dir", + dentry->d_name.len, + dentry->d_name.name); + return ERR_PTR(-EIO); + } inode = ext4_iget(dir->i_sb, ino); if (inode == ERR_PTR(-ESTALE)) { EXT4_ERROR_INODE(dir,
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