ksmbd: smbd: fix missing client's memory region invalidation

if the Channel of a SMB2 WRITE request is
SMB2_CHANNEL_RDMA_V1_INVALIDTE, a client
does not invalidate its memory regions but
ksmbd must do it by sending a SMB2 WRITE response
with IB_WR_SEND_WITH_INV.

But if errors occur while processing a SMB2
READ/WRITE request, ksmbd sends a response
with IB_WR_SEND. So a client could use memory
regions already in use.
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/smb2pdu.c

@@ -6124,25 +6124,33 @@ static noinline int smb2_read_pipe(struct ksmbd_work *work)
 	return err;
 }
 
-static ssize_t smb2_read_rdma_channel(struct ksmbd_work *work,
-				      struct smb2_read_req *req, void *data_buf,
-				      size_t length)
+static int smb2_set_remote_key_for_rdma(struct ksmbd_work *work,
+					struct smb2_buffer_desc_v1 *desc,
+					__le32 Channel,
+					__le16 ChannelInfoOffset,
+					__le16 ChannelInfoLength)
 {
-	struct smb2_buffer_desc_v1 *desc =
-		(struct smb2_buffer_desc_v1 *)&req->Buffer[0];
-	int err;
-
 	if (work->conn->dialect == SMB30_PROT_ID &&
-	    req->Channel != SMB2_CHANNEL_RDMA_V1)
+	    Channel != SMB2_CHANNEL_RDMA_V1)
 		return -EINVAL;
 
-	if (req->ReadChannelInfoOffset == 0 ||
-	    le16_to_cpu(req->ReadChannelInfoLength) < sizeof(*desc))
+	if (ChannelInfoOffset == 0 ||
+	    le16_to_cpu(ChannelInfoLength) < sizeof(*desc))
 		return -EINVAL;
 
 	work->need_invalidate_rkey =
-		(req->Channel == SMB2_CHANNEL_RDMA_V1_INVALIDATE);
+		(Channel == SMB2_CHANNEL_RDMA_V1_INVALIDATE);
 	work->remote_key = le32_to_cpu(desc->token);
+	return 0;
+}
+
+static ssize_t smb2_read_rdma_channel(struct ksmbd_work *work,
+				      struct smb2_read_req *req, void *data_buf,
+				      size_t length)
+{
+	struct smb2_buffer_desc_v1 *desc =
+		(struct smb2_buffer_desc_v1 *)&req->Buffer[0];
+	int err;
 
 	err = ksmbd_conn_rdma_write(work->conn, data_buf, length,
 				    le32_to_cpu(desc->token),
@@ -6165,7 +6173,7 @@ int smb2_read(struct ksmbd_work *work)
 	struct ksmbd_conn *conn = work->conn;
 	struct smb2_read_req *req;
 	struct smb2_read_rsp *rsp;
-	struct ksmbd_file *fp;
+	struct ksmbd_file *fp = NULL;
 	loff_t offset;
 	size_t length, mincount;
 	ssize_t nbytes = 0, remain_bytes = 0;
@@ -6179,6 +6187,18 @@ int smb2_read(struct ksmbd_work *work)
 		return smb2_read_pipe(work);
 	}
 
+	if (req->Channel == SMB2_CHANNEL_RDMA_V1_INVALIDATE ||
+	    req->Channel == SMB2_CHANNEL_RDMA_V1) {
+		err = smb2_set_remote_key_for_rdma(work,
+						   (struct smb2_buffer_desc_v1 *)
+						   &req->Buffer[0],
+						   req->Channel,
+						   req->ReadChannelInfoOffset,
+						   req->ReadChannelInfoLength);
+		if (err)
+			goto out;
+	}
+
 	fp = ksmbd_lookup_fd_slow(work, le64_to_cpu(req->VolatileFileId),
 				  le64_to_cpu(req->PersistentFileId));
 	if (!fp) {
@@ -6364,21 +6384,6 @@ static ssize_t smb2_write_rdma_channel(struct ksmbd_work *work,
 
 	desc = (struct smb2_buffer_desc_v1 *)&req->Buffer[0];
 
-	if (work->conn->dialect == SMB30_PROT_ID &&
-	    req->Channel != SMB2_CHANNEL_RDMA_V1)
-		return -EINVAL;
-
-	if (req->Length != 0 || req->DataOffset != 0)
-		return -EINVAL;
-
-	if (req->WriteChannelInfoOffset == 0 ||
-	    le16_to_cpu(req->WriteChannelInfoLength) < sizeof(*desc))
-		return -EINVAL;
-
-	work->need_invalidate_rkey =
-		(req->Channel == SMB2_CHANNEL_RDMA_V1_INVALIDATE);
-	work->remote_key = le32_to_cpu(desc->token);
-
 	data_buf = kvmalloc(length, GFP_KERNEL | __GFP_ZERO);
 	if (!data_buf)
 		return -ENOMEM;
@@ -6425,6 +6430,20 @@ int smb2_write(struct ksmbd_work *work)
 		return smb2_write_pipe(work);
 	}
 
+	if (req->Channel == SMB2_CHANNEL_RDMA_V1 ||
+	    req->Channel == SMB2_CHANNEL_RDMA_V1_INVALIDATE) {
+		if (req->Length != 0 || req->DataOffset != 0)
+			return -EINVAL;
+		err = smb2_set_remote_key_for_rdma(work,
+						   (struct smb2_buffer_desc_v1 *)
+						   &req->Buffer[0],
+						   req->Channel,
+						   req->WriteChannelInfoOffset,
+						   req->WriteChannelInfoLength);
+		if (err)
+			goto out;
+	}
+
 	if (!test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE)) {
 		ksmbd_debug(SMB, "User does not have write permission\n");
 		err = -EACCES;