| From | Willy Tarreau <> | Subject | [PATCH 3.10 042/139] ext4: fix overflow caused by missing cast in ext4_resize_fs() | Date | Wed, 1 Nov 2017 22:17:42 +0100 |
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From: Jerry Lee <jerrylee@qnap.com>
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> Cc: stable@vger.kernel.org Signed-off-by: Willy Tarreau <w@1wt.eu> --- 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 cf0a704..f6190fd 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1911,7 +1911,8 @@ 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 */ } -- 2.8.0.rc2.1.gbe9624a
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