From mboxrd@z Thu Jan 1 00:00:00 1970 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 5F264C38145 for ; Wed, 7 Sep 2022 11:57:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230031AbiIGL5Q (ORCPT ); Wed, 7 Sep 2022 07:57:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229577AbiIGL5N (ORCPT ); Wed, 7 Sep 2022 07:57:13 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DBBECE79; Wed, 7 Sep 2022 04:57:11 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D32646189F; Wed, 7 Sep 2022 11:57:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ADD70C433C1; Wed, 7 Sep 2022 11:57:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1662551830; bh=LBURqqGm6uHN296hjpUzL5apDqPzW15rc2NLka5Q+GM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iwG0EOgf6p6wl8IrIbXNzXxgI1Iyo8SlmLWuyq+cu9HLnX8fszNZqZm/2bBYzPRVB 6moL5BBSPSeaPjItW9o9/ywtu6Qu+OlhsiB2U25ySXW/sXzAHoeu4DzJ+3g1LDC6KP GkvymYRcBDNo+dR100YOOEfyPPX8HWvGXhxyep/U= Date: Wed, 7 Sep 2022 13:57:07 +0200 From: Greg KH To: Rondreis Cc: balbi@kernel.org, stern@rowland.harvard.edu, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb: gadget: Assign a unique name for each configfs driver Message-ID: References: <20220907112210.11949-1-linhaoguo86@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220907112210.11949-1-linhaoguo86@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 07, 2022 at 07:22:10PM +0800, Rondreis wrote: > When fuzzing the kernel, I couldn't use configfs to attach more than one > gadget. When attaching the second gadget with a different UDC it always > failed and the kernel message said: > > Error: Driver 'configfs-gadget' is already registered, aborting... > UDC core: g1: driver registration failed: -16 > > The problem is that when creating multiple gadgets with configfs and > binding them to different UDCs, the UDC drivers have the same name > "configfs-gadget". Because of the addition of the "gadget" bus, > naming conflicts will occur when more than one UDC drivers > registered to the bus. > > It's not an isolated case, this patch refers to the commit f2d8c2606825 > ("usb: gadget: Fix non-unique driver names in raw-gadget driver"). > Each configfs-gadget driver will be assigned a unique name > "configfs-gadget.N", with a different value of N for each driver instance. Please wrap your changelog text at 72 columns like the documentation asks for. > Reported-and-tested-by: Rondreis > Signed-off-by: Rondreis You can't reported and test your own patch :) Also, I need a full name here, what you use to sign legal documents. And, what commit does this "fix"? This should have worked before the gadget bus happened, so it is a regression and needs a valid "Fixes:" tag, right? > --- > drivers/usb/gadget/configfs.c | 39 ++++++++++++++++++++++++++++++++--- > 1 file changed, 36 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c > index 3a6b4926193e..7e7ff94dbaab 100644 > --- a/drivers/usb/gadget/configfs.c > +++ b/drivers/usb/gadget/configfs.c > @@ -4,12 +4,18 @@ > #include > #include > #include > +#include > #include > #include > #include "configfs.h" > #include "u_f.h" > #include "u_os_desc.h" > > +#define DRIVER_NAME "configfs-gadget" > + > +static DEFINE_IDA(driver_id_numbers); > +#define DRIVER_DRIVER_NAME_LENGTH_MAX 32 Why this number? > + > int check_user_usb_string(const char *name, > struct usb_gadget_strings *stringtab_dev) > { > @@ -46,6 +52,7 @@ struct gadget_info { > > struct usb_composite_driver composite; > struct usb_composite_dev cdev; > + int driver_id_number; > bool use_os_desc; > char b_vendor_code; > char qw_sign[OS_STRING_QW_SIGN_LEN]; > @@ -252,6 +259,11 @@ static int unregister_gadget(struct gadget_info *gi) > return ret; > kfree(gi->composite.gadget_driver.udc_name); > gi->composite.gadget_driver.udc_name = NULL; > + > + kfree(gi->composite.gadget_driver.driver.name); Are you sure the driver name is safe to free here? You don't own the lifecycle of this structure, so this feels very risky. > + if (gi->driver_id_number >= 0) How would that ever be negative? > + ida_free(&driver_id_numbers, gi->driver_id_number); > + > return 0; > } > > @@ -1571,7 +1583,6 @@ static const struct usb_gadget_driver configfs_driver_template = { > .max_speed = USB_SPEED_SUPER_PLUS, > .driver = { > .owner = THIS_MODULE, > - .name = "configfs-gadget", > }, > .match_existing_only = 1, > }; > @@ -1580,6 +1591,8 @@ static struct config_group *gadgets_make( > struct config_group *group, > const char *name) > { > + int ret = 0; > + char *driver_driver_name; Why not just "driver_name"? > struct gadget_info *gi; > > gi = kzalloc(sizeof(*gi), GFP_KERNEL); > @@ -1609,6 +1622,7 @@ static struct config_group *gadgets_make( > gi->composite.suspend = NULL; > gi->composite.resume = NULL; > gi->composite.max_speed = USB_SPEED_SUPER_PLUS; > + gi->driver_id_number = -1; What is this magic "-1"? > > spin_lock_init(&gi->spinlock); > mutex_init(&gi->lock); > @@ -1622,16 +1636,35 @@ static struct config_group *gadgets_make( > > gi->composite.gadget_driver = configfs_driver_template; > > + ret = ida_alloc(&driver_id_numbers, GFP_KERNEL); > + if (ret < 0) > + goto err; > + gi->driver_id_number = ret; > + > + driver_driver_name = kmalloc(DRIVER_DRIVER_NAME_LENGTH_MAX, GFP_KERNEL); > + if (!driver_driver_name) { > + ret = -ENOMEM; > + goto err_free_driver_id_number; > + } > + snprintf(driver_driver_name, DRIVER_DRIVER_NAME_LENGTH_MAX, > + DRIVER_NAME ".%d", gi->driver_id_number); What happens if this fails? And please use the recommended function for this string operation, which isn't snprintf(). > + gi->composite.gadget_driver.driver.name = driver_driver_name; > + > gi->composite.gadget_driver.function = kstrdup(name, GFP_KERNEL); > gi->composite.name = gi->composite.gadget_driver.function; > > - if (!gi->composite.gadget_driver.function) > + if (!gi->composite.gadget_driver.function) { > + ret = -ENOMEM; > goto err; > + } > > return &gi->group; > + > +err_free_driver_id_number: > + ida_free(&driver_id_numbers, gi->driver_id_number); > err: > kfree(gi); > - return ERR_PTR(-ENOMEM); > + return ERR_PTR(ret); You leaked the memory you allocated for "driver_driver_name" :( thanks, greg k-h