| Message ID | 1603907723-19499-1-git-send-email-macpaul.lin@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] usb: gadget: configfs: Fix use-after-free issue with udc_name | expand |
On Thu, 2020-10-29 at 01:55 +0800, Macpaul Lin wrote: > From: Eddie Hung <eddie.hung@mediatek.com> > > 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 > --- > Changes for v2: > - Fix typo %s/contex/context, Thanks Peter. > > 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 56051bb..d9743f4 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) Sorry, it looks like still a base64 encoded mail. I'll feedback to our IT department again. Please ignore this mail. Thanks Macpaul Lin
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c index 56051bb..d9743f4 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)