From patchwork Sat Dec 25 21:55:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marian Postevca X-Patchwork-Id: 528270 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DDCBDC433EF for ; Sat, 25 Dec 2021 21:55:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232965AbhLYVz1 (ORCPT ); Sat, 25 Dec 2021 16:55:27 -0500 Received: from mail.mutex.one ([62.77.152.124]:45978 "EHLO mail.mutex.one" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232964AbhLYVz0 (ORCPT ); Sat, 25 Dec 2021 16:55:26 -0500 Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.mutex.one (Postfix) with ESMTP id 7E0EE16C0042; Sat, 25 Dec 2021 23:55:25 +0200 (EET) X-Virus-Scanned: Debian amavisd-new at mail.mutex.one Received: from mail.mutex.one ([127.0.0.1]) by localhost (mail.mutex.one [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mGfHLR-yuOM4; Sat, 25 Dec 2021 23:55:25 +0200 (EET) From: Marian Postevca DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mutex.one; s=default; t=1640469325; bh=r2japACvwnnpQt1HvqvEF9hq63V9GWftBQ1aWH5sseY=; h=From:To:Cc:Subject:Date:From; b=mps57X4hclXkxUXoRC4nfP1GDmcnYjkBA+1YzAWfbyAOl0CL9i8rBWjhMAkEnsdoP ofFdnPs6bvU0FE+ecVEpSrgYlLO/244r3weitCmDNBllWvHSZGOAZRgySomRXd81Z1 Avohhihx0HwnihH4axm1SqdXPGNDdB/Itd9EFVhI= To: stable@vger.kernel.org Cc: Marian Postevca Subject: [PATCH 4.19] usb: gadget: u_ether: fix race in setting MAC address in setup phase Date: Sat, 25 Dec 2021 23:55:08 +0200 Message-Id: <20211225215508.22282-1-posteuca@mutex.one> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 890d5b40908bfd1a79be018d2d297cf9df60f4ee upstream. When listening for notifications through netlink of a new interface being registered, sporadically, it is possible for the MAC to be read as zero. The zero MAC address lasts a short period of time and then switches to a valid random MAC address. This causes problems for netd in Android, which assumes that the interface is malfunctioning and will not use it. In the good case we get this log: InterfaceController::getCfg() ifName usb0 hwAddr 92:a8:f0:73:79:5b ipv4Addr 0.0.0.0 flags 0x1002 In the error case we get these logs: InterfaceController::getCfg() ifName usb0 hwAddr 00:00:00:00:00:00 ipv4Addr 0.0.0.0 flags 0x1002 netd : interfaceGetCfg("usb0") netd : interfaceSetCfg() -> ServiceSpecificException (99, "[Cannot assign requested address] : ioctl() failed") The reason for the issue is the order in which the interface is setup, it is first registered through register_netdev() and after the MAC address is set. Fixed by first setting the MAC address of the net_device and after that calling register_netdev(). Cc: stable@vger.kernel.org Signed-off-by: Marian Postevca Fixes: bcd4a1c40bee885e ("usb: gadget: u_ether: construct with default values and add setters/getters") --- drivers/usb/gadget/function/u_ether.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c index d7a12161e5531..1b3e674e6330d 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -860,19 +860,23 @@ int gether_register_netdev(struct net_device *net) { struct eth_dev *dev; struct usb_gadget *g; - struct sockaddr sa; int status; if (!net->dev.parent) return -EINVAL; dev = netdev_priv(net); g = dev->gadget; + + memcpy(net->dev_addr, dev->dev_mac, ETH_ALEN); + net->addr_assign_type = NET_ADDR_RANDOM; + status = register_netdev(net); if (status < 0) { dev_dbg(&g->dev, "register_netdev failed, %d\n", status); return status; } else { INFO(dev, "HOST MAC %pM\n", dev->host_mac); + INFO(dev, "MAC %pM\n", dev->dev_mac); /* two kinds of host-initiated state changes: * - iff DATA transfer is active, carrier is "on" @@ -880,15 +884,6 @@ int gether_register_netdev(struct net_device *net) */ netif_carrier_off(net); } - sa.sa_family = net->type; - memcpy(sa.sa_data, dev->dev_mac, ETH_ALEN); - rtnl_lock(); - status = dev_set_mac_address(net, &sa); - rtnl_unlock(); - if (status) - pr_warn("cannot set self ethernet address: %d\n", status); - else - INFO(dev, "MAC %pM\n", dev->dev_mac); return status; }