From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: [PATCH 2/2] ext4: add ext4_iget_normal() which is to be used for dir tree lookups Date: Sun, 5 Oct 2014 22:48:02 -0400 Message-ID: <1412563682-5720-2-git-send-email-tytso@mit.edu> References: <20141005001239.GD27150@sli.dy.fi> <1412563682-5720-1-git-send-email-tytso@mit.edu> Cc: Theodore Ts'o To: Ext4 Developers List Return-path: Received: from imap.thunk.org ([74.207.234.97]:37565 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751926AbaJFCsJ (ORCPT ); Sun, 5 Oct 2014 22:48:09 -0400 In-Reply-To: <1412563682-5720-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: If there is a corrupted file system which has directory entries that point at reserved, metadata inodes, prohibit them from being used by treating them the same way we treat Boot Loader inodes --- that is, mark them to be bad inodes. This prohibits them from being opened, deleted, or modified via chmod, chown, utimes, etc. In particular, this prevents a corrupted file system which has a directory entry which points at the journal inode from being deleted and being released, after which point Much Hilarity Ensues. Reported-by: Sami Liedes Signed-off-by: Theodore Ts'o --- fs/ext4/ext4.h | 1 + fs/ext4/inode.c | 10 ++++++++++ fs/ext4/namei.c | 4 ++-- fs/ext4/super.c | 2 +- 4 files changed, 14 insertions(+), 3 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 1eb5b7b..012e89b 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2109,6 +2109,7 @@ int do_journal_get_write_access(handle_t *handle, #define CONVERT_INLINE_DATA 2 extern struct inode *ext4_iget(struct super_block *, unsigned long); +extern struct inode *ext4_iget_normal(struct super_block *, unsigned long); extern int ext4_write_inode(struct inode *, struct writeback_control *); extern int ext4_setattr(struct dentry *, struct iattr *); extern int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry, diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 59983b2..437622c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4104,6 +4104,16 @@ bad_inode: return ERR_PTR(ret); } +struct inode *ext4_iget_normal(struct super_block *sb, unsigned long ino) +{ + struct inode *ret_inode = ext4_iget(sb, ino); + + if (ret_inode && !IS_ERR(ret_inode) && + ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO) + make_bad_inode(ret_inode); + return ret_inode; +} + static int ext4_inode_blocks_set(handle_t *handle, struct ext4_inode *raw_inode, struct ext4_inode_info *ei) diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index a2a9d40..7037ecf 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1417,7 +1417,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi dentry); return ERR_PTR(-EIO); } - inode = ext4_iget(dir->i_sb, ino); + inode = ext4_iget_normal(dir->i_sb, ino); if (inode == ERR_PTR(-ESTALE)) { EXT4_ERROR_INODE(dir, "deleted inode referenced: %u", @@ -1450,7 +1450,7 @@ struct dentry *ext4_get_parent(struct dentry *child) return ERR_PTR(-EIO); } - return d_obtain_alias(ext4_iget(child->d_inode->i_sb, ino)); + return d_obtain_alias(ext4_iget_normal(child->d_inode->i_sb, ino)); } /* diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 1070d6e..a0811cc 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1001,7 +1001,7 @@ static struct inode *ext4_nfs_get_inode(struct super_block *sb, * Currently we don't know the generation for parent directory, so * a generation of 0 means "accept any" */ - inode = ext4_iget(sb, ino); + inode = ext4_iget_normal(sb, ino); if (IS_ERR(inode)) return ERR_CAST(inode); if (generation && inode->i_generation != generation) { -- 2.1.0