6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
[ Upstream commit 2e94e5bb94a3e641a25716a560bf474225fda83c ]
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>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/exfat/file.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 64c31867bc761..525c3ad411ea3 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -578,6 +578,16 @@ 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) {
+ unsigned long align = pos | iov_iter_alignment(iter);
+
+ if (!IS_ALIGNED(align, i_blocksize(inode)) &&
+ !IS_ALIGNED(align, bdev_logical_block_size(inode->i_sb->s_bdev))) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ }
+
if (pos > valid_size) {
ret = exfat_file_zeroed_range(file, valid_size, pos);
if (ret < 0 && ret != -ENOSPC) {
--
2.43.0
