http: Fix parsing invalid url cause to crash

Reason:
For example, if an url is lack of leading 'http:' by mistake, it causes to http_parser_parse_url() cannot parse http host item,
and then pass the null host pointer to _get_host_header(), crash happens.

Fix:
http added null pointer check now.

Closes https://jira.espressif.com:8443/browse/ESPAT-953

components/esp_http_client/esp_http_client.c

@@ -665,6 +665,10 @@ esp_http_client_handle_t esp_http_client_init(const esp_http_client_config_t *co
     const char *user_agent = config->user_agent == NULL ? DEFAULT_HTTP_USER_AGENT : config->user_agent;
 
     if (config->host != NULL && config->path != NULL) {
+        if (client->connection_info.host == NULL) {
+            ESP_LOGE(TAG, "invalid host");
+            goto error;
+        }
         host_name = _get_host_header(client->connection_info.host, client->connection_info.port);
         if (host_name == NULL) {
             ESP_LOGE(TAG, "Failed to allocate memory for host header");
@@ -684,6 +688,10 @@ esp_http_client_handle_t esp_http_client_init(const esp_http_client_config_t *co
             ESP_LOGE(TAG, "Failed to set URL");
             goto error;
         }
+        if (client->connection_info.host == NULL) {
+            ESP_LOGE(TAG, "invalid host");
+            goto error;
+        }
         host_name = _get_host_header(client->connection_info.host, client->connection_info.port);
         if (host_name == NULL) {
             ESP_LOGE(TAG, "Failed to allocate memory for host header");

components/esp_http_client/test/test_http_client.c

@@ -132,3 +132,16 @@ TEST_CASE("Username and password will not reset if new absolute URL doesnot spec
     TEST_ASSERT_NOT_NULL(value);
     esp_http_client_cleanup(client);
 }
+
+/**
+ * Test case to verify that, esp_http_client_init() should return NULL if configuration has url with empty hostname.
+ **/
+TEST_CASE("esp_http_client_init() should return NULL if configured with wrong url", "[ESP HTTP CLIENT]")
+{
+    esp_http_client_config_t config = {
+        .url = "//httpbin.org/post",
+    };
+    esp_http_client_handle_t client = esp_http_client_init(&config);
+    TEST_ASSERT_NULL(client);
+    esp_http_client_cleanup(client);
+}