ksmbd: remove smb2_buf_length in smb2_hdr

To move smb2_hdr to smbfs_common, This patch remove smb2_buf_length
variable in smb2_hdr. Also, declare smb2_get_msg function to get smb2
request/response from ->request/response_buf.

Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/auth.c

@@ -873,9 +873,9 @@ int ksmbd_gen_preauth_integrity_hash(struct ksmbd_conn *conn, char *buf,
 				     __u8 *pi_hash)
 {
 	int rc;
-	struct smb2_hdr *rcv_hdr = (struct smb2_hdr *)buf;
+	struct smb2_hdr *rcv_hdr = smb2_get_msg(buf);
 	char *all_bytes_msg = (char *)&rcv_hdr->ProtocolId;
-	int msg_size = be32_to_cpu(rcv_hdr->smb2_buf_length);
+	int msg_size = get_rfc1002_len(buf);
 	struct ksmbd_crypto_ctx *ctx = NULL;
 
 	if (conn->preauth_info->Preauth_HashId !=

fs/ksmbd/connection.c

@@ -158,14 +158,13 @@ void ksmbd_conn_wait_idle(struct ksmbd_conn *conn)
 int ksmbd_conn_write(struct ksmbd_work *work)
 {
 	struct ksmbd_conn *conn = work->conn;
-	struct smb_hdr *rsp_hdr = work->response_buf;
 	size_t len = 0;
 	int sent;
 	struct kvec iov[3];
 	int iov_idx = 0;
 
 	ksmbd_conn_try_dequeue_request(work);
-	if (!rsp_hdr) {
+	if (!work->response_buf) {
 		pr_err("NULL response header\n");
 		return -EINVAL;
 	}
@@ -177,7 +176,7 @@ int ksmbd_conn_write(struct ksmbd_work *work)
 	}
 
 	if (work->aux_payload_sz) {
-		iov[iov_idx] = (struct kvec) { rsp_hdr, work->resp_hdr_sz };
+		iov[iov_idx] = (struct kvec) { work->response_buf, work->resp_hdr_sz };
 		len += iov[iov_idx++].iov_len;
 		iov[iov_idx] = (struct kvec) { work->aux_payload_buf, work->aux_payload_sz };
 		len += iov[iov_idx++].iov_len;
@@ -185,8 +184,8 @@ int ksmbd_conn_write(struct ksmbd_work *work)
 		if (work->tr_buf)
 			iov[iov_idx].iov_len = work->resp_hdr_sz;
 		else
-			iov[iov_idx].iov_len = get_rfc1002_len(rsp_hdr) + 4;
-		iov[iov_idx].iov_base = rsp_hdr;
+			iov[iov_idx].iov_len = get_rfc1002_len(work->response_buf) + 4;
+		iov[iov_idx].iov_base = work->response_buf;
 		len += iov[iov_idx++].iov_len;
 	}
 

fs/ksmbd/ksmbd_work.h

@@ -92,7 +92,7 @@ struct ksmbd_work {
  */
 static inline void *ksmbd_resp_buf_next(struct ksmbd_work *work)
 {
-	return work->response_buf + work->next_smb2_rsp_hdr_off;
+	return work->response_buf + work->next_smb2_rsp_hdr_off + 4;
 }
 
 /**
@@ -101,7 +101,7 @@ static inline void *ksmbd_resp_buf_next(struct ksmbd_work *work)
  */
 static inline void *ksmbd_req_buf_next(struct ksmbd_work *work)
 {
-	return work->request_buf + work->next_smb2_rcv_hdr_off;
+	return work->request_buf + work->next_smb2_rcv_hdr_off + 4;
 }
 
 struct ksmbd_work *ksmbd_alloc_work_struct(void);

fs/ksmbd/oplock.c

@@ -629,10 +629,10 @@ static void __smb2_oplock_break_noti(struct work_struct *wk)
 		return;
 	}
 
-	rsp_hdr = work->response_buf;
+	rsp_hdr = smb2_get_msg(work->response_buf);
 	memset(rsp_hdr, 0, sizeof(struct smb2_hdr) + 2);
-	rsp_hdr->smb2_buf_length =
-		cpu_to_be32(smb2_hdr_size_no_buflen(conn->vals));
+	*(__be32 *)work->response_buf =
+		cpu_to_be32(conn->vals->header_size);
 	rsp_hdr->ProtocolId = SMB2_PROTO_NUMBER;
 	rsp_hdr->StructureSize = SMB2_HEADER_STRUCTURE_SIZE;
 	rsp_hdr->CreditRequest = cpu_to_le16(0);
@@ -645,7 +645,7 @@ static void __smb2_oplock_break_noti(struct work_struct *wk)
 	rsp_hdr->SessionId = 0;
 	memset(rsp_hdr->Signature, 0, 16);
 
-	rsp = work->response_buf;
+	rsp = smb2_get_msg(work->response_buf);
 
 	rsp->StructureSize = cpu_to_le16(24);
 	if (!br_info->open_trunc &&
@@ -659,7 +659,7 @@ static void __smb2_oplock_break_noti(struct work_struct *wk)
 	rsp->PersistentFid = cpu_to_le64(fp->persistent_id);
 	rsp->VolatileFid = cpu_to_le64(fp->volatile_id);
 
-	inc_rfc1001_len(rsp, 24);
+	inc_rfc1001_len(work->response_buf, 24);
 
 	ksmbd_debug(OPLOCK,
 		    "sending oplock break v_id %llu p_id = %llu lock level = %d\n",
@@ -736,10 +736,10 @@ static void __smb2_lease_break_noti(struct work_struct *wk)
 		return;
 	}
 
-	rsp_hdr = work->response_buf;
+	rsp_hdr = smb2_get_msg(work->response_buf);
 	memset(rsp_hdr, 0, sizeof(struct smb2_hdr) + 2);
-	rsp_hdr->smb2_buf_length =
-		cpu_to_be32(smb2_hdr_size_no_buflen(conn->vals));
+	*(__be32 *)work->response_buf =
+		cpu_to_be32(conn->vals->header_size);
 	rsp_hdr->ProtocolId = SMB2_PROTO_NUMBER;
 	rsp_hdr->StructureSize = SMB2_HEADER_STRUCTURE_SIZE;
 	rsp_hdr->CreditRequest = cpu_to_le16(0);
@@ -752,7 +752,7 @@ static void __smb2_lease_break_noti(struct work_struct *wk)
 	rsp_hdr->SessionId = 0;
 	memset(rsp_hdr->Signature, 0, 16);
 
-	rsp = work->response_buf;
+	rsp = smb2_get_msg(work->response_buf);
 	rsp->StructureSize = cpu_to_le16(44);
 	rsp->Epoch = br_info->epoch;
 	rsp->Flags = 0;
@@ -768,7 +768,7 @@ static void __smb2_lease_break_noti(struct work_struct *wk)
 	rsp->AccessMaskHint = 0;
 	rsp->ShareMaskHint = 0;
 
-	inc_rfc1001_len(rsp, 44);
+	inc_rfc1001_len(work->response_buf, 44);
 
 	ksmbd_conn_write(work);
 	ksmbd_free_work_struct(work);
@@ -1398,7 +1398,7 @@ struct lease_ctx_info *parse_lease_state(void *open_req)
 	if (!lreq)
 		return NULL;
 
-	data_offset = (char *)req + 4 + le32_to_cpu(req->CreateContextsOffset);
+	data_offset = (char *)req + le32_to_cpu(req->CreateContextsOffset);
 	cc = (struct create_context *)data_offset;
 	do {
 		cc = (struct create_context *)((char *)cc + next);
@@ -1462,7 +1462,7 @@ struct create_context *smb2_find_context_vals(void *open_req, const char *tag)
 	 * CreateContextsOffset and CreateContextsLength are guaranteed to
 	 * be valid because of ksmbd_smb2_check_message().
 	 */
-	cc = (struct create_context *)((char *)req + 4 +
+	cc = (struct create_context *)((char *)req +
 				       le32_to_cpu(req->CreateContextsOffset));
 	remain_len = le32_to_cpu(req->CreateContextsLength);
 	do {

fs/ksmbd/smb2misc.c

@@ -351,7 +351,7 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work)
 	struct smb2_hdr *hdr = &pdu->hdr;
 	int command;
 	__u32 clc_len;  /* calculated length */
-	__u32 len = get_rfc1002_len(pdu);
+	__u32 len = get_rfc1002_len(work->request_buf);
 
 	if (le32_to_cpu(hdr->NextCommand) > 0)
 		len = le32_to_cpu(hdr->NextCommand);

fs/ksmbd/smb2pdu.h

@@ -130,11 +130,6 @@
 	cpu_to_le16(__SMB2_HEADER_STRUCTURE_SIZE)
 
 struct smb2_hdr {
-	__be32 smb2_buf_length;	/* big endian on wire */
-				/*
-				 * length is only two or three bytes - with
-				 * one or two byte type preceding it that MBZ
-				 */
 	__le32 ProtocolId;	/* 0xFE 'S' 'M' 'B' */
 	__le16 StructureSize;	/* 64 */
 	__le16 CreditCharge;	/* MBZ */
@@ -253,14 +248,14 @@ struct preauth_integrity_info {
 	__u8			Preauth_HashValue[PREAUTH_HASHVALUE_SIZE];
 };
 
-/* offset is sizeof smb2_negotiate_rsp - 4 but rounded up to 8 bytes. */
+/* offset is sizeof smb2_negotiate_rsp but rounded up to 8 bytes. */
 #ifdef CONFIG_SMB_SERVER_KERBEROS5
-/* sizeof(struct smb2_negotiate_rsp) - 4 =
+/* sizeof(struct smb2_negotiate_rsp) =
  * header(64) + response(64) + GSS_LENGTH(96) + GSS_PADDING(0)
  */
 #define OFFSET_OF_NEG_CONTEXT	0xe0
 #else
-/* sizeof(struct smb2_negotiate_rsp) - 4 =
+/* sizeof(struct smb2_negotiate_rsp) =
  * header(64) + response(64) + GSS_LENGTH(74) + GSS_PADDING(6)
  */
 #define OFFSET_OF_NEG_CONTEXT	0xd0
@@ -1705,4 +1700,13 @@ int smb2_ioctl(struct ksmbd_work *work);
 int smb2_oplock_break(struct ksmbd_work *work);
 int smb2_notify(struct ksmbd_work *ksmbd_work);
 
+/*
+ * Get the body of the smb2 message excluding the 4 byte rfc1002 headers
+ * from request/response buffer.
+ */
+static inline void *smb2_get_msg(void *buf)
+{
+	return buf + 4;
+}
+
 #endif	/* _SMB2PDU_H */

fs/ksmbd/smb_common.c

@@ -239,14 +239,14 @@ int ksmbd_lookup_dialect_by_id(__le16 *cli_dialects, __le16 dialects_count)
 static int ksmbd_negotiate_smb_dialect(void *buf)
 {
 	int smb_buf_length = get_rfc1002_len(buf);
-	__le32 proto = ((struct smb2_hdr *)buf)->ProtocolId;
+	__le32 proto = ((struct smb2_hdr *)smb2_get_msg(buf))->ProtocolId;
 
 	if (proto == SMB2_PROTO_NUMBER) {
 		struct smb2_negotiate_req *req;
 		int smb2_neg_size =
-			offsetof(struct smb2_negotiate_req, Dialects) - 4;
+			offsetof(struct smb2_negotiate_req, Dialects);
 
-		req = (struct smb2_negotiate_req *)buf;
+		req = (struct smb2_negotiate_req *)smb2_get_msg(buf);
 		if (smb2_neg_size > smb_buf_length)
 			goto err_out;
 
@@ -445,11 +445,12 @@ int ksmbd_smb_negotiate_common(struct ksmbd_work *work, unsigned int command)
 	struct ksmbd_conn *conn = work->conn;
 	int ret;
 
-	conn->dialect = ksmbd_negotiate_smb_dialect(work->request_buf);
+	conn->dialect =
+		ksmbd_negotiate_smb_dialect(work->request_buf);
 	ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
 
 	if (command == SMB2_NEGOTIATE_HE) {
-		struct smb2_hdr *smb2_hdr = work->request_buf;
+		struct smb2_hdr *smb2_hdr = smb2_get_msg(work->request_buf);
 
 		if (smb2_hdr->ProtocolId != SMB2_PROTO_NUMBER) {
 			ksmbd_debug(SMB, "Downgrade to SMB1 negotiation\n");

fs/ksmbd/smb_common.h

@@ -477,12 +477,6 @@ struct smb_version_cmds {
 	int (*proc)(struct ksmbd_work *swork);
 };
 
-static inline size_t
-smb2_hdr_size_no_buflen(struct smb_version_values *vals)
-{
-	return vals->header_size - 4;
-}
-
 int ksmbd_min_protocol(void);
 int ksmbd_max_protocol(void);
 

fs/ksmbd/transport_rdma.c

@@ -484,7 +484,7 @@ static int smb_direct_check_recvmsg(struct smb_direct_recvmsg *recvmsg)
 		struct smb_direct_data_transfer *req =
 			(struct smb_direct_data_transfer *)recvmsg->packet;
 		struct smb2_hdr *hdr = (struct smb2_hdr *)(recvmsg->packet
-				+ le32_to_cpu(req->data_offset) - 4);
+				+ le32_to_cpu(req->data_offset));
 		ksmbd_debug(RDMA,
 			    "CreditGranted: %u, CreditRequested: %u, DataLength: %u, RemainingDataLength: %u, SMB: %x, Command: %u\n",
 			    le16_to_cpu(req->credits_granted),