Unaligned direct writes are invalid and should return an error
without making any changes, rather than extending ->valid_size
and then returning an error. Therefore, alignment checking is
required before extending ->valid_size.
Fixes: 11a347fb6cef ("exfat: change to get file size from DataLength")
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
Co-developed-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
---
fs/exfat/file.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index a25d7eb789f4..a00f3f1b2cbb 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -584,6 +584,12 @@ static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
if (ret < 0)
goto unlock;
+ if ((iocb->ki_flags & IOCB_DIRECT) &&
+ EXFAT_BLK_OFFSET(pos | ret, inode->i_sb)) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
if (pos > valid_size) {
ret = exfat_extend_valid_size(file, pos);
if (ret < 0 && ret != -ENOSPC) {
--
2.43.0
