| Message ID | 20211223052626.1631331-1-nobuhiro1.iwamatsu@toshiba.co.jp |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC/PATCH,for,4.4.y] usb: gadget: configfs: Fix use-after-free issue with udc_name | expand |
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
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
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)