[PATCH 5.15.y] ksmbd: smbdirect: verify remaining_data_length respects max_fragmented_recv_size

[Sasha Levin <sashal@kernel.org>]

From: Stefan Metzmacher <metze@samba.org>

[ Upstream commit e1868ba37fd27c6a68e31565402b154beaa65df0 ]

This is inspired by the check for data_offset + data_length.

Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Cc: stable@vger.kernel.org
Fixes: 2ea086e35c3d ("ksmbd: add buffer validation for smb direct")
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
[ No data_offset ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ksmbd/transport_rdma.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/ksmbd/transport_rdma.c b/fs/ksmbd/transport_rdma.c
index 2f02632905842..53e543129fe12 100644
--- a/fs/ksmbd/transport_rdma.c
+++ b/fs/ksmbd/transport_rdma.c
@@ -548,7 +548,7 @@ static void recv_done(struct ib_cq *cq, struct ib_wc *wc)
 	case SMB_DIRECT_MSG_DATA_TRANSFER: {
 		struct smb_direct_data_transfer *data_transfer =
 			(struct smb_direct_data_transfer *)recvmsg->packet;
-		unsigned int data_length;
+		u32 remaining_data_length, data_length;
 		int avail_recvmsg_count, receive_credits;
 
 		if (wc->byte_len <
@@ -558,7 +558,16 @@ static void recv_done(struct ib_cq *cq, struct ib_wc *wc)
 			return;
 		}
 
+		remaining_data_length = le32_to_cpu(data_transfer->remaining_data_length);
 		data_length = le32_to_cpu(data_transfer->data_length);
+		if (remaining_data_length > t->max_fragmented_recv_size ||
+		    data_length > t->max_fragmented_recv_size ||
+		    (u64)remaining_data_length + (u64)data_length >
+		    (u64)t->max_fragmented_recv_size) {
+			put_recvmsg(t, recvmsg);
+			smb_direct_disconnect_rdma_connection(t);
+			return;
+		}
 		if (data_length) {
 			if (wc->byte_len < sizeof(struct smb_direct_data_transfer) +
 			    (u64)data_length) {
-- 
2.51.0