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@medi... 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