Ensure we correctly calculate reply credits over all returned

SMB2 replies, and do as Windows does and return the total in the
last SMB2 reply. Fixes an issue found by Christian M Ambach <christian.ambach@de.ibm.com>
(and thanks to Christian for the initial patch this was based on).

1 files changed, 13 insertions, 4 deletions

diff --git a/source3/smbd/smb2_server.c b/source3/smbd/smb2_server.c
index dbb0089d70..851e2fd7ef 100644
--- a/source3/smbd/smb2_server.c
+++ b/source3/smbd/smb2_server.c
@@ -517,13 +517,24 @@ static void smb2_calculate_credits(const struct smbd_smb2_request *inreq,
 				struct smbd_smb2_request *outreq)
 {
 	int count, idx;
+	uint16_t total_credits = 0;
 
 	count = outreq->out.vector_count;
 
 	for (idx=1; idx < count; idx += 3) {
+		uint8_t *outhdr = (uint8_t *)outreq->out.vector[idx].iov_base;
 		smb2_set_operation_credit(outreq->sconn,
 			&inreq->in.vector[idx],
 			&outreq->out.vector[idx]);
+		/* To match Windows, count up what we
+		   just granted. */
+		total_credits += SVAL(outhdr, SMB2_HDR_CREDIT);
+		/* Set to zero in all but the last reply. */
+		if (idx + 3 < count) {
+			SSVAL(outhdr, SMB2_HDR_CREDIT, 0);
+		} else {
+			SSVAL(outhdr, SMB2_HDR_CREDIT, total_credits);
+		}
 	}
 }
 
@@ -1851,11 +1862,9 @@ static NTSTATUS smbd_smb2_request_reply(struct smbd_smb2_request *req)
 
 	smb2_setup_nbt_length(req->out.vector, req->out.vector_count);
 
-	/* Set credit for this operation (zero credits if this
+	/* Set credit for these operations (zero credits if this
 	   is a final reply for an async operation). */
-	smb2_set_operation_credit(req->sconn,
-			&req->in.vector[i],
-			&req->out.vector[i]);
+	smb2_calculate_credits(req, req);
 
 	if (req->do_signing) {
 		NTSTATUS status;