libubus: limit stack depth for incoming invoke requests

diff --git a/libubus.c b/libubus.c
index 94b0044957e275deab7391545205485dae0071d5..4502f245323a7d47b604f4bc1cb2d18d1615cc9c 100644 (file)
--- a/libubus.c
+++ b/libubus.c
@@ -56,6 +56,13 @@ struct ubus_pending_data {
        struct blob_attr data[];
 };
 
+struct ubus_pending_invoke {
+       struct list_head list;
+       struct ubus_msghdr hdr;
+};
+
+static void ubus_process_pending_invoke(struct ubus_context *ctx);
+
 static int ubus_cmp_id(const void *k1, const void *k2, void *ptr)
 {
        const uint32_t *id1 = k1, *id2 = k2;
@@ -387,6 +394,7 @@ send:
 
 static void ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
 {
+       struct ubus_pending_invoke *pending;
        struct ubus_request *req;
 
        switch(hdr->type) {
@@ -405,11 +413,36 @@ static void ubus_process_msg(struct ubus_context *ctx, struct ubus_msghdr *hdr)
                break;
 
        case UBUS_MSG_INVOKE:
-               ubus_process_invoke(ctx, hdr);
+               if (ctx->stack_depth > 2) {
+                       pending = calloc(1, sizeof(*pending) +
+                               blob_raw_len(hdr->data));
+
+                       if (!pending)
+                               return;
+
+                       memcpy(&pending->hdr, hdr, sizeof(*hdr) +
+                               blob_raw_len(hdr->data));
+                       list_add(&pending->list, &ctx->pending);
+               } else {
+                       ubus_process_invoke(ctx, hdr);
+               }
                break;
        }
 }
 
+static void ubus_process_pending_invoke(struct ubus_context *ctx)
+{
+       struct ubus_pending_invoke *pending, *tmp;
+
+       list_for_each_entry_safe(pending, tmp, &ctx->pending, list) {
+               list_del(&pending->list);
+               ubus_process_msg(ctx, &pending->hdr);
+               free(pending);
+               if (ctx->stack_depth > 2)
+                       break;
+       }
+}
+
 void ubus_abort_request(struct ubus_context *ctx, struct ubus_request *req)
 {
        if (!list_empty(&req->list))
@@ -486,12 +519,14 @@ int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req,
        ubus_complete_request_async(ctx, req);
        req->complete_cb = ubus_sync_req_cb;
 
+       ctx->stack_depth++;
        while (!req->status_msg) {
                bool cancelled = uloop_cancelled;
                uloop_cancelled = false;
                uloop_run();
                uloop_cancelled = cancelled;
        }
+       ctx->stack_depth--;
 
        if (timeout)
                uloop_timeout_cancel(&cb.timeout);
@@ -506,6 +541,9 @@ int ubus_complete_request(struct ubus_context *ctx, struct ubus_request *req,
        if (!registered)
                uloop_fd_delete(&ctx->sock);
 
+       if (!ctx->stack_depth)
+               ubus_process_pending_invoke(ctx);
+
        return status;
 }
 
@@ -868,6 +906,7 @@ struct ubus_context *ubus_connect(const char *path)
        ctx->connection_lost = ubus_default_connection_lost;
 
        INIT_LIST_HEAD(&ctx->requests);
+       INIT_LIST_HEAD(&ctx->pending);
        avl_init(&ctx->objects, ubus_cmp_id, false, NULL);
 
        if (!ctx->local_id)

diff --git a/libubus.h b/libubus.h
index 55c59e4ae8b03b6bbc82dd6468f1199fda966405..0dcbb6d3e93da0825e64813da1a43c8115db7b78 100644 (file)
--- a/libubus.h
+++ b/libubus.h
@@ -93,11 +93,13 @@ struct ubus_event_handler {
 struct ubus_context {
        struct list_head requests;
        struct avl_tree objects;
+       struct list_head pending;
 
        struct uloop_fd sock;
 
        uint32_t local_id;
        uint32_t request_seq;
+       int stack_depth;
 
        void (*connection_lost)(struct ubus_context *ctx);