From 10a7a1b8babbdd5684684da31482eab1931316f0 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Stefan=20Br=C3=BCns?= <stefan.bruens@rwth-aachen.de>
Date: Tue, 6 Sep 2016 04:36:45 +0200
Subject: [PATCH] ext4: Avoid corruption of directories with hash tree indexes
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit
While directories can be read using the old linear scan method, adding a
new file would require updating the index tree (alternatively, the whole
tree could be removed).
Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
---
fs/ext4/ext4_write.c | 5 +++++
include/ext4fs.h | 1 +
2 files changed, 6 insertions(+)
diff --git a/fs/ext4/ext4_write.c b/fs/ext4/ext4_write.c
index a52804e8e1..8554793f4f 100644
--- a/fs/ext4/ext4_write.c
+++ b/fs/ext4/ext4_write.c
@@ -881,6 +881,11 @@ int ext4fs_write(const char *fname, unsigned char *buffer,
goto fail;
if (ext4fs_iget(parent_inodeno, g_parent_inode))
goto fail;
+ /* do not mess up a directory using hash trees */
+ if (le32_to_cpu(g_parent_inode->flags) & EXT4_INDEX_FL) {
+ printf("hash tree directory\n");
+ goto fail;
+ }
/* check if the filename is already present in root */
existing_file_inodeno = ext4fs_filename_unlink(filename);
if (existing_file_inodeno != -1) {
diff --git a/include/ext4fs.h b/include/ext4fs.h
index e3f6216fa9..6e31c73812 100644
--- a/include/ext4fs.h
+++ b/include/ext4fs.h
@@ -28,6 +28,7 @@
#define __EXT4__
#include <ext_common.h>
+#define EXT4_INDEX_FL 0x00001000 /* Inode uses hash tree index */
#define EXT4_EXTENTS_FL 0x00080000 /* Inode uses extents */
#define EXT4_EXT_MAGIC 0xf30a
#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM 0x0010
--
2.39.5