[PATCH 3.10 068/123] ext4: add ext4_iget_normal() which is to be used for dir tree lookups

From: Greg Kroah-Hartman
Date: Tue Nov 11 2014 - 20:53:25 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Theodore Ts'o <tytso@xxxxxxx>

commit f4bb2981024fc91b23b4d09a8817c415396dbabb upstream.

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 its blocks released, after which point Much Hilarity Ensues.

Reported-by: Sami Liedes <sami.liedes@xxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/ext4/ext4.h | 1 +
fs/ext4/inode.c | 7 +++++++
fs/ext4/namei.c | 4 ++--
fs/ext4/super.c | 2 +-
4 files changed, 11 insertions(+), 3 deletions(-)

--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2088,6 +2088,7 @@ int do_journal_get_write_access(handle_t
#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,
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4351,6 +4351,13 @@ bad_inode:
return ERR_PTR(ret);
}

+struct inode *ext4_iget_normal(struct super_block *sb, unsigned long ino)
+{
+ if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
+ return ERR_PTR(-EIO);
+ return ext4_iget(sb, ino);
+}
+
static int ext4_inode_blocks_set(handle_t *handle,
struct ext4_inode *raw_inode,
struct ext4_inode_info *ei)
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1430,7 +1430,7 @@ static struct dentry *ext4_lookup(struct
dentry->d_name.name);
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",
@@ -1461,7 +1461,7 @@ struct dentry *ext4_get_parent(struct de
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));
}

/*
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -964,7 +964,7 @@ static struct inode *ext4_nfs_get_inode(
* 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) {


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/