[PATCH 7/8] staging: erofs: fix integer overflow on 32-bit platform

Chao Yu
2018-08-12T14:02:52Z

From: Gao Xiang <gaoxiang25@huawei.com>

This patch fixes integer overflow on multiplication
of 32-bit `lcn' in z_erofs_map_blocks_iter.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
drivers/staging/erofs/unzip_vle.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
index ae99b6811d4a..6c5b0a312592 100644
--- a/drivers/staging/erofs/unzip_vle.c
+++ b/drivers/staging/erofs/unzip_vle.c
@@ -1513,7 +1513,7 @@ static erofs_off_t vle_get_logical_extent_head(
*flags ^= EROFS_MAP_ZIPPED;
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
/* clustersize should be a power of two */
- ofs = ((unsigned long long)lcn << clusterbits) +
+ ofs = ((u64)lcn << clusterbits) +
(le16_to_cpu(di->di_clusterofs) & (clustersize - 1));
*pcn = le32_to_cpu(di->di_u.blkaddr);
break;
@@ -1595,7 +1595,7 @@ int z_erofs_map_blocks_iter(struct inode *inode,
/* by default, compressed */
map->m_flags |= EROFS_MAP_ZIPPED;

- end = (u64)(lcn + 1) * clustersize;
+ end = ((u64)lcn + 1) * clustersize;

cluster_type = vle_cluster_type(di);

@@ -1611,7 +1611,7 @@ int z_erofs_map_blocks_iter(struct inode *inode,
}

if (ofs_rem > logical_cluster_ofs) {
- ofs = lcn * clustersize | logical_cluster_ofs;
+ ofs = (u64)lcn * clustersize | logical_cluster_ofs;
pcn = le32_to_cpu(di->di_u.blkaddr);
break;
}
@@ -1623,7 +1623,7 @@ int z_erofs_map_blocks_iter(struct inode *inode,
err = -EIO;
goto unmap_out;
}
- end = (lcn-- * clustersize) | logical_cluster_ofs;
+ end = ((u64)lcn-- * clustersize) | logical_cluster_ofs;
/* fallthrough */
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
/* get the correspoinding first chunk */
--
2.18.0