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authorEddie Hung <eddie.hung@mediatek.com>2020-12-29 13:53:35 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-01-04 18:53:06 +0300
commit64e6bbfff52db4bf6785fab9cffab850b2de6870 (patch)
tree7cda7fe656a8ece2d887f9ba007fb5b0a1c8baa8 /drivers/usb/gadget
parenta1383b3537a7bea1c213baa7878ccc4ecf4413b5 (diff)
downloadlinux-64e6bbfff52db4bf6785fab9cffab850b2de6870.tar.xz
usb: gadget: configfs: Fix use-after-free issue with udc_name
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>
Diffstat (limited to 'drivers/usb/gadget')
-rw-r--r--drivers/usb/gadget/configfs.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 56051bb97349..d9743f4b56c3 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)