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authorJerry Lee <jerrylee@qnap.com>2017-08-06 01:18:31 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-08-11 09:08:48 -0700
commit31cd127ca69a1aedd24b9aa7ac806e6071c84655 (patch)
tree3de3062ec8247747959bf4be8cd167bbcb7f1f84
parentbad9f6142ce1141b7e4969d898cf0e2d61e90d5b (diff)
ext4: fix overflow caused by missing cast in ext4_resize_fs()
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>
-rw-r--r--fs/ext4/resize.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 34038e3598d5..74516efd874c 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1926,7 +1926,8 @@ 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 */
}