* [RFC/PATCH for 4.4.y] usb: gadget: configfs: Fix use-after-free issue with udc_name
@ 2021-12-23 5:26 Nobuhiro Iwamatsu
2021-12-27 12:47 ` Greg KH
0 siblings, 1 reply; 3+ messages in thread
From: Nobuhiro Iwamatsu @ 2021-12-23 5:26 UTC (permalink / raw)
To: stable
Cc: gregkh, sashal, Eddie Hung, Macpaul Lin, Peter Chen,
Nobuhiro Iwamatsu
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(-)
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 0ef3f4e452428c..6e1172450c7345 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -241,7 +241,16 @@ 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)
{
- return sprintf(page, "%s\n", to_gadget_info(item)->udc_name ?: "");
+ struct gadget_info *gi = to_gadget_info(item);
+ char *udc_name;
+ int ret;
+
+ mutex_lock(&gi->lock);
+ udc_name = gi->udc_name;
+ ret = sprintf(page, "%s\n", udc_name ?: "");
+ mutex_unlock(&gi->lock);
+
+ return ret;
}
static int unregister_gadget(struct gadget_info *gi)
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [RFC/PATCH for 4.4.y] usb: gadget: configfs: Fix use-after-free issue with udc_name
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
0 siblings, 1 reply; 3+ messages in thread
From: Greg KH @ 2021-12-27 12:47 UTC (permalink / raw)
To: Nobuhiro Iwamatsu; +Cc: stable, sashal, Eddie Hung, Macpaul Lin, Peter Chen
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC/PATCH for 4.4.y] usb: gadget: configfs: Fix use-after-free issue with udc_name
2021-12-27 12:47 ` Greg KH
@ 2021-12-27 13:10 ` Greg KH
0 siblings, 0 replies; 3+ messages in thread
From: Greg KH @ 2021-12-27 13:10 UTC (permalink / raw)
To: Nobuhiro Iwamatsu; +Cc: stable, sashal, Eddie Hung, Macpaul Lin, Peter Chen
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
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-12-27 13:11 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
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 is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox