From: Greg KH <gregkh@linuxfoundation.org>
To: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Cc: stable@vger.kernel.org, sashal@kernel.org,
Eddie Hung <eddie.hung@mediatek.com>,
Macpaul Lin <macpaul.lin@mediatek.com>,
Peter Chen <peter.chen@nxp.com>
Subject: Re: [RFC/PATCH for 4.4.y] usb: gadget: configfs: Fix use-after-free issue with udc_name
Date: Mon, 27 Dec 2021 14:10:54 +0100 [thread overview]
Message-ID: <Ycm7Xh2oBEGqSZPi@kroah.com> (raw)
In-Reply-To: <Ycm151MQzlAC0tC3@kroah.com>
On Mon, Dec 27, 2021 at 01:47:35PM +0100, Greg KH wrote:
> On Thu, Dec 23, 2021 at 02:26:26PM +0900, Nobuhiro Iwamatsu wrote:
> > From: Eddie Hung <eddie.hung@mediatek.com>
> >
> > commit 64e6bbfff52db4bf6785fab9cffab850b2de6870 upstream.
> >
> > 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.
> >
> > Context 1:
> > gadget_dev_desc_UDC_store()->unregister_gadget()->
> > free udc_name->set udc_name to NULL
> >
> > Context 2:
> > 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>
> > Reviewed-by: Peter Chen <peter.chen@nxp.com>
> > Cc: stable@vger.kernel.org
> > Link: https://lore.kernel.org/r/1609239215-21819-1-git-send-email-macpaul.lin@mediatek.com
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > [Reference: CVE-2021-39648]
> > [iwamatsu: struct usb_gadget_driver does not have udc_name variable.
> > Change struct gadget_info's udc_name.]
> > Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
> > ---
> > drivers/usb/gadget/configfs.c | 11 ++++++++++-
> > 1 file changed, 10 insertions(+), 1 deletion(-)
>
> Now queued up, thanks.
>
> greg k-h
Oops, nope, this gives me a build warning, something is wrong with this
change:
CC [M] drivers/usb/gadget/configfs.o
drivers/usb/gadget/configfs.c: In function ‘gadget_dev_desc_UDC_show’:
drivers/usb/gadget/configfs.c:249:18: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
249 | udc_name = gi->udc_name;
| ^
Please always test-build your patches :(
thanks,
greg k-h
prev parent reply other threads:[~2021-12-27 13:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-23 5:26 [RFC/PATCH for 4.4.y] usb: gadget: configfs: Fix use-after-free issue with udc_name Nobuhiro Iwamatsu
2021-12-27 12:47 ` Greg KH
2021-12-27 13:10 ` Greg KH [this message]
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