ext4: recover from filesystem corruption when reading
Some fixes when reading EXT files and directory entries were identified
after using e2fuzz to corrupt an EXT3 filesystem:
- Stop reading directory entries if the offset becomes badly aligned.
- Avoid overwriting memory by clamping the length used to zero the buffer
in ext4fs_read_file. Also sanity check blocksize.
Signed-off-by: Ian Ray <ian.ray@ge.com>
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Reviewed-by: Stefano Babic <sbabic@denx.de>
diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index 31952f4..dac9545 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -660,6 +660,11 @@
offset = 0;
do {
+ if (offset & 3) {
+ printf("Badly aligned ext2_dirent\n");
+ break;
+ }
+
dir = (struct ext2_dirent *)(block_buffer + offset);
direntname = (char*)(dir) + sizeof(struct ext2_dirent);
@@ -880,6 +885,11 @@
offset = 0;
do {
+ if (offset & 3) {
+ printf("Badly aligned ext2_dirent\n");
+ break;
+ }
+
previous_dir = dir;
dir = (struct ext2_dirent *)(block_buffer + offset);
direntname = (char *)(dir) + sizeof(struct ext2_dirent);