s3:smb2cli_base: make use of tevent_req_defer_callback()

In order to notify requests of transport layer errors,
we need to defer the triggering of the callbacks,
otherwise we may crash, if one of the callbacks
destroys the cli_state.

metze

1 files changed, 64 insertions, 28 deletions

diff --git a/source3/libsmb/smb2cli_base.c b/source3/libsmb/smb2cli_base.c
index 1b5a8a6798..ac7d423b57 100644
--- a/source3/libsmb/smb2cli_base.c
+++ b/source3/libsmb/smb2cli_base.c
@@ -139,6 +139,36 @@ static bool smb2cli_req_set_pending(struct tevent_req *req)
 	return true;
 }
 
+static void smb2cli_notify_pending(struct cli_state *cli, NTSTATUS status)
+{
+	if (cli->fd != -1) {
+		close(cli->fd);
+		cli->fd = -1;
+	}
+
+	/*
+	 * Cancel all pending requests. We don't do a for-loop walking
+	 * cli->pending because that array changes in
+	 * cli_smb_req_destructor().
+	 */
+	while (talloc_array_length(cli->pending) > 0) {
+		struct tevent_req *req;
+		struct smb2cli_req_state *state;
+
+		req = cli->pending[0];
+		state = tevent_req_data(req, struct smb2cli_req_state);
+
+		smb2cli_req_unset_pending(req);
+
+		/*
+		 * we need to defer the callback, because we may notify more
+		 * then one caller.
+		 */
+		tevent_req_defer_callback(req, state->ev);
+		tevent_req_nterror(req, status);
+	}
+}
+
 struct tevent_req *smb2cli_req_create(TALLOC_CTX *mem_ctx,
 				      struct tevent_context *ev,
 				      struct cli_state *cli,
@@ -312,11 +342,8 @@ static void smb2cli_writev_done(struct tevent_req *subreq)
 	nwritten = writev_recv(subreq, &err);
 	TALLOC_FREE(subreq);
 	if (nwritten == -1) {
-		if (state->cli->fd != -1) {
-			close(state->cli->fd);
-			state->cli->fd = -1;
-		}
-		tevent_req_nterror(req, map_nt_error_from_unix(err));
+		/* here, we need to notify all pending requests */
+		smb2cli_notify_pending(state->cli, map_nt_error_from_unix(err));
 		return;
 	}
 }
@@ -457,18 +484,28 @@ static void smb2cli_inbuf_received(struct tevent_req *subreq)
 	received = read_smb_recv(subreq, frame, &inbuf, &err);
 	TALLOC_FREE(subreq);
 	if (received == -1) {
-		if (cli->fd != -1) {
-			close(cli->fd);
-			cli->fd = -1;
-		}
-		status = map_nt_error_from_unix(err);
-		goto fail;
+		/*
+		 * We need to close the connection and notify
+		 * all pending requests.
+		 */
+		smb2cli_notify_pending(cli, map_nt_error_from_unix(err));
+		TALLOC_FREE(frame);
+		return;
 	}
 
 	status = smb2cli_inbuf_parse_compound(inbuf, frame,
 					      &iov, &num_iov);
 	if (!NT_STATUS_IS_OK(status)) {
-		goto fail;
+		/*
+		 * if we cannot parse the incoming pdu,
+		 * the connection becomes unusable.
+		 *
+		 * We need to close the connection and notify
+		 * all pending requests.
+		 */
+		smb2cli_notify_pending(cli, status);
+		TALLOC_FREE(frame);
+		return;
 	}
 
 	for (i=1; i<num_iov; i+=3) {
@@ -481,14 +518,27 @@ static void smb2cli_inbuf_received(struct tevent_req *subreq)
 			cli, BVAL(inhdr, SMB2_HDR_MESSAGE_ID));
 		if (req == NULL) {
 			/*
-			 * oplock breaks ??
+			 * TODO: handle oplock breaks and async responses
+			 */
+
+			/*
+			 * We need to close the connection and notify
+			 * all pending requests.
 			 */
-			goto fail;
+			smb2cli_notify_pending(cli, status);
+			TALLOC_FREE(frame);
+			return;
 		}
 		smb2cli_req_unset_pending(req);
 		state = tevent_req_data(req, struct smb2cli_req_state);
 
 		/*
+		 * There might be more than one response
+		 * we need to defer the notifications
+		 */
+		tevent_req_defer_callback(req, state->ev);
+
+		/*
 		 * Note: here we use talloc_reference() in a way
 		 *       that does not expose it to the caller.
 		 */
@@ -506,20 +556,6 @@ static void smb2cli_inbuf_received(struct tevent_req *subreq)
 	}
 
 	TALLOC_FREE(frame);
-	return;
- fail:
-	/*
-	 * Cancel all pending requests. We don't do a for-loop walking
-	 * cli->pending because that array changes in
-	 * cli_smb_req_destructor().
-	 */
-	while (talloc_array_length(cli->pending) > 0) {
-		req = cli->pending[0];
-		smb2cli_req_unset_pending(req);
-		tevent_req_nterror(req, status);
-	}
-
-	TALLOC_FREE(frame);
 }
 
 NTSTATUS smb2cli_req_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,