[PATCH] ksmbd: use u8 for SMB2 oplock level values

[Karl Mehltretter]

The SMB2 oplock level is an unsigned 8-bit wire value, but
smb20_oplock_break_ack() stores it in a plain char. On architectures where
plain char is signed, the value 0xff becomes -1 and cannot compare equal to
SMB2_OPLOCK_LEVEL_LEASE (0xff). The acknowledgment is consequently rejected
with STATUS_INVALID_OPLOCK_PROTOCOL instead of the intended
STATUS_INVALID_PARAMETER.

Use u8 for the request and response oplock-level variables. This preserves
all wire values in their original representation.

Fixes: 80a56d4a826c ("ksmbd: align SMB2 oplock break ack handling")
Cc: stable@xxxxxxxxxxxxxxx
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehltretter@xxxxxxxxx>
---
 fs/smb/server/smb2pdu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 6b8809f..6074bdd 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -11444,7 +11444,7 @@ static void smb20_oplock_break_ack(struct ksmbd_work *work)
 	__le32 status = STATUS_SUCCESS;
 	int ret;
 	u64 volatile_id, persistent_id;
-	char req_oplevel = 0, rsp_oplevel = 0;
+	u8 req_oplevel = 0, rsp_oplevel = 0;
 
 	WORK_BUFFERS(work, req, rsp);
 
-- 
2.53.0