From: Peter Chen <peter.chen@nxp.com>
To: Macpaul Lin <macpaul.lin@mediatek.com>
Cc: Felipe Balbi <balbi@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-mediatek@lists.infradead.org"
<linux-mediatek@lists.infradead.org>,
Mediatek WSD Upstream <wsd_upstream@mediatek.com>,
Macpaul Lin <macpaul.lin@gmail.com>,
Eddie Hung <eddie.hung@mediatek.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH] usb: gadget: configfs: Fix use-after-free issue with udc_name
Date: Fri, 17 Jul 2020 04:14:08 +0000 [thread overview]
Message-ID: <20200717041406.GC17070@b29397-desktop> (raw)
In-Reply-To: <1594881666-8843-1-git-send-email-macpaul.lin@mediatek.com>
On 20-07-16 14:41:06, Macpaul Lin wrote:
> There is a use-after-free issue, if access udc_name
> in function gadget_dev_desc_UDC_store after another context
> free udc_name in function unregister_gadget.
>
> Contex 1:
%s/contex/context
> gadget_dev_desc_UDC_store()->unregister_gadget()->
> free udc_name->set udc_name to NULL
>
> Contex 2:
The same, otherwise:
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Peter
> gadget_dev_desc_UDC_show()-> access udc_name
>
> Call trace:
> dump_backtrace+0x0/0x340
> show_stack+0x14/0x1c
> dump_stack+0xe4/0x134
> print_address_description+0x78/0x478
> __kasan_report+0x270/0x2ec
> kasan_report+0x10/0x18
> __asan_report_load1_noabort+0x18/0x20
> string+0xf4/0x138
> vsnprintf+0x428/0x14d0
> sprintf+0xe4/0x12c
> gadget_dev_desc_UDC_show+0x54/0x64
> configfs_read_file+0x210/0x3a0
> __vfs_read+0xf0/0x49c
> vfs_read+0x130/0x2b4
> SyS_read+0x114/0x208
> el0_svc_naked+0x34/0x38
>
> Add mutex_lock to protect this kind of scenario.
>
> Signed-off-by: Eddie Hung <eddie.hung@mediatek.com>
> Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
> Cc: stable@vger.kernel.org
> ---
> drivers/usb/gadget/configfs.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
> index 9dc06a4e1b30..21110b2865b9 100644
> --- a/drivers/usb/gadget/configfs.c
> +++ b/drivers/usb/gadget/configfs.c
> @@ -221,9 +221,16 @@ static ssize_t gadget_dev_desc_bcdUSB_store(struct config_item *item,
>
> static ssize_t gadget_dev_desc_UDC_show(struct config_item *item, char *page)
> {
> - char *udc_name = to_gadget_info(item)->composite.gadget_driver.udc_name;
> + struct gadget_info *gi = to_gadget_info(item);
> + char *udc_name;
> + int ret;
> +
> + mutex_lock(&gi->lock);
> + udc_name = gi->composite.gadget_driver.udc_name;
> + ret = sprintf(page, "%s\n", udc_name ?: "");
> + mutex_unlock(&gi->lock);
>
> - return sprintf(page, "%s\n", udc_name ?: "");
> + return ret;
> }
>
> static int unregister_gadget(struct gadget_info *gi)
> --
> 2.18.0
--
Thanks,
Peter Chen
next prev parent reply other threads:[~2020-07-17 4:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-16 6:41 [PATCH] usb: gadget: configfs: Fix use-after-free issue with udc_name Macpaul Lin
2020-07-17 4:14 ` Peter Chen [this message]
2020-07-18 2:45 ` [PATCH v2] " Macpaul Lin
2020-07-18 2:58 ` Macpaul Lin
2020-07-21 11:33 ` Greg Kroah-Hartman
2020-07-22 1:59 ` Macpaul Lin
2020-10-20 6:36 ` Macpaul Lin
2020-10-27 9:23 ` Felipe Balbi
2020-11-01 5:37 ` [RESEND PATCH " Macpaul Lin
2020-12-29 10:53 ` [PATCH RESEND " Macpaul Lin
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