From: Jerry Lee <jerrylee@qnap.com>
Date: Sun, 6 Aug 2017 01:18:31 -0400
Subject: [PATCH] ext4: fix overflow caused by missing cast in ext4_resize_fs()
References: bnc#1060662
Patch-mainline: v4.12.6
Git-commit: aec51758ce10a9c847a62a48a168f8c804c6e053
commit aec51758ce10a9c847a62a48a168f8c804c6e053 upstream.
On a 32-bit platform, the value of n_blcoks_count may be wrong during
the file system is resized to size larger than 2^32 blocks. This may
caused the superblock being corrupted with zero blocks count.
Fixes: 1c6bd7173d66
Signed-off-by: Jerry Lee <jerrylee@qnap.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
fs/ext4/resize.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index c3ed9021b781..035cd3f4785e 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1927,7 +1927,8 @@ retry:
n_desc_blocks = o_desc_blocks +
le16_to_cpu(es->s_reserved_gdt_blocks);
n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
- n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
+ n_blocks_count = (ext4_fsblk_t)n_group *
+ EXT4_BLOCKS_PER_GROUP(sb);
n_group--; /* set to last group number */
}
--
2.14.2