On Fri, 10 May 2019, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 43151d6c usb-fuzzer: main usb gadget fuzzer driver > git tree: https://github.com/google/kasan.git usb-fuzzer > console output: https://syzkaller.appspot.com/x/log.txt?x=124794d8a00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=4183eeef650d1234 > dashboard link: https://syzkaller.appspot.com/bug?extid=71f1e64501a309fcc012 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=176a53d0a00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+71f1e64501a309fcc012@xxxxxxxxxxxxxxxxxxxxxxxxx > > usb 1-1: Using ep0 maxpacket: 8 > ================================================================== > BUG: KASAN: slab-out-of-bounds in usb_get_bos_descriptor+0x8be/0x8fb > drivers/usb/core/config.c:976 > Write of size 1 at addr ffff8880a48e38ec by task kworker/0:2/533 Insufficient descriptor size check. Alan Stern #syz test: https://github.com/google/kasan.git usb-fuzzer drivers/usb/core/config.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) Index: usb-devel/drivers/usb/core/config.c =================================================================== --- usb-devel.orig/drivers/usb/core/config.c +++ usb-devel/drivers/usb/core/config.c @@ -932,8 +932,8 @@ int usb_get_bos_descriptor(struct usb_de /* Get BOS descriptor */ ret = usb_get_descriptor(dev, USB_DT_BOS, 0, bos, USB_DT_BOS_SIZE); - if (ret < USB_DT_BOS_SIZE) { - dev_err(ddev, "unable to get BOS descriptor\n"); + if (ret < USB_DT_BOS_SIZE || bos->bLength < USB_DT_BOS_SIZE) { + dev_err(ddev, "unable to get BOS descriptor or descriptor too short\n"); if (ret >= 0) ret = -ENOMSG; kfree(bos);
