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 X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E7A8C433DB for ; Thu, 11 Mar 2021 10:54:10 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B3E9F64FC4 for ; Thu, 11 Mar 2021 10:54:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B3E9F64FC4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=canonical.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ovoGnMSmqqJxL+dHtjKnjxBLScxMVThUy6fmLWFoZLw=; b=Sd9gksIsviL6X9kbAkOJ3NGsX dsMvNCbHe7FV5bTA3HJ9hEFvCk8tRbB7S3bLherk85WZa/ajS+VKv6+zdFrAhMYAuQylV1SksO5+X wvwq5Dl0oD1YA/QqM2IIOTmYq3QFdcgi766/sz9ajKiA+leSQ3XkxoiFD0PT8dHmINB12a6sMVGuV y9e1HrMvJb/NG7aFUcjBCvtxH9s4ecAV0tmiuwOfNuoFcl1+PT/iPc0lfDmHL3oDhSxLt203BIlvu IIBPvXN81qc3gtsjGbHFrS+TBGaCAs0smjQ8Pa4Zd/RDtCQC39Xv4ste6qG+vvElW6m87rGsLX3rS cr8nM7HUw==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lKIvg-008spd-GA; Thu, 11 Mar 2021 10:52:32 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lKIvZ-008soY-TE; Thu, 11 Mar 2021 10:52:30 +0000 Received: from [179.93.213.27] (helo=mussarela) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1lKIvR-0008VO-Pm; Thu, 11 Mar 2021 10:52:18 +0000 Date: Thu, 11 Mar 2021 07:52:10 -0300 From: Thadeu Lima de Souza Cascardo To: Macpaul Lin Cc: Jim Lin , Felipe Balbi , Greg Kroah-Hartman , Matthias Brugger , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Ainge Hsu , Eddie Hung , Kuohong Wang , Mediatek WSD Upstream , Macpaul Lin , stable@vger.kernel.org Subject: Re: [PATCH v4] usb: gadget: configfs: Fix KASAN use-after-free Message-ID: <20210311105210.GS10958@mussarela> References: <1484647168-30135-1-git-send-email-jilin@nvidia.com> <1615444961-13376-1-git-send-email-macpaul.lin@mediatek.com> <1615445632.13420.2.camel@mtkswgap22> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1615445632.13420.2.camel@mtkswgap22> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210311_105226_955032_52126F5D X-CRM114-Status: GOOD ( 28.74 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Mar 11, 2021 at 02:53:52PM +0800, Macpaul Lin wrote: > On Thu, 2021-03-11 at 14:42 +0800, Macpaul Lin wrote: > > From: Jim Lin > > > > When gadget is disconnected, running sequence is like this. > > . composite_disconnect > > . Call trace: > > usb_string_copy+0xd0/0x128 > > gadget_config_name_configuration_store+0x4 > > gadget_config_name_attr_store+0x40/0x50 > > configfs_write_file+0x198/0x1f4 > > vfs_write+0x100/0x220 > > SyS_write+0x58/0xa8 > > . configfs_composite_unbind > > . configfs_composite_bind > > > > In configfs_composite_bind, it has > > "cn->strings.s = cn->configuration;" > > > > When usb_string_copy is invoked. it would > > allocate memory, copy input string, release previous pointed memory space, > > and use new allocated memory. > > > > When gadget is connected, host sends down request to get information. > > Call trace: > > usb_gadget_get_string+0xec/0x168 > > lookup_string+0x64/0x98 > > composite_setup+0xa34/0x1ee8 > > > > If gadget is disconnected and connected quickly, in the failed case, > > cn->configuration memory has been released by usb_string_copy kfree but > > configfs_composite_bind hasn't been run in time to assign new allocated > > "cn->configuration" pointer to "cn->strings.s". > > > > When "strlen(s->s) of usb_gadget_get_string is being executed, the dangling > > memory is accessed, "BUG: KASAN: use-after-free" error occurs. > > > > Signed-off-by: Jim Lin > > Signed-off-by: Macpaul Lin > > Cc: stable@vger.kernel.org > > --- > > Changes in v2: > > Changes in v3: > > - Change commit description > > Changes in v4: > > - Fix build error and adapt patch to kernel-5.12-rc1. > > Replace definition "MAX_USB_STRING_WITH_NULL_LEN" with > > "USB_MAX_STRING_WITH_NULL_LEN". > > - Note: The patch v2 and v3 has been verified by > > Thadeu Lima de Souza Cascardo > > http://spinics.net/lists/kernel/msg3840792.html > > Dear Cascardo, > > Would you please help to confirm if you've tested it on Linux PC, > Chrome OS, or an Android OS? I tested v3 on Ubuntu GNU/Linux. I will test v4. Cascardo. > > Thanks! > Macpaul Lin > > > and > > Macpaul Lin on Android kernels. > > http://lkml.org/lkml/2020/6/11/8 > > - The patch is suggested to be applied to LTS versions. > > > > drivers/usb/gadget/configfs.c | 14 ++++++++++---- > > 1 file changed, 10 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c > > index 0d56f33..15a607c 100644 > > --- a/drivers/usb/gadget/configfs.c > > +++ b/drivers/usb/gadget/configfs.c > > @@ -97,6 +97,8 @@ struct gadget_config_name { > > struct list_head list; > > }; > > > > +#define USB_MAX_STRING_WITH_NULL_LEN (USB_MAX_STRING_LEN+1) > > + > > static int usb_string_copy(const char *s, char **s_copy) > > { > > int ret; > > @@ -106,12 +108,16 @@ static int usb_string_copy(const char *s, char **s_copy) > > if (ret > USB_MAX_STRING_LEN) > > return -EOVERFLOW; > > > > - str = kstrdup(s, GFP_KERNEL); > > - if (!str) > > - return -ENOMEM; > > + if (copy) { > > + str = copy; > > + } else { > > + str = kmalloc(USB_MAX_STRING_WITH_NULL_LEN, GFP_KERNEL); > > + if (!str) > > + return -ENOMEM; > > + } > > + strcpy(str, s); > > if (str[ret - 1] == '\n') > > str[ret - 1] = '\0'; > > - kfree(copy); > > *s_copy = str; > > return 0; > > } > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel