On Tue, 3 Sep 2019, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: eea39f24 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=174761b6600000 > kernel config: https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e > dashboard link: https://syzkaller.appspot.com/bug?extid=35f4d916c623118d576e > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1706275a600000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+35f4d916c623118d576e@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KASAN: slab-out-of-bounds in memcmp+0xa6/0xb0 lib/string.c:904 > Read of size 1 at addr ffff8881d175bed6 by task kworker/0:3/2746 > > CPU: 0 PID: 2746 Comm: kworker/0:3 Not tainted 5.3.0-rc5+ #28 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Workqueue: usb_hub_wq hub_event > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0xca/0x13e lib/dump_stack.c:113 > print_address_description+0x6a/0x32c mm/kasan/report.c:351 > __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482 > kasan_report+0xe/0x12 mm/kasan/common.c:612 > memcmp+0xa6/0xb0 lib/string.c:904 > memcmp include/linux/string.h:400 [inline] > descriptors_changed drivers/usb/core/hub.c:5579 [inline] > usb_reset_and_verify_device+0x564/0x1300 drivers/usb/core/hub.c:5729 Diagnostic patch. #syz test: https://github.com/google/kasan.git eea39f24 Index: usb-devel/drivers/usb/core/hub.c =================================================================== --- usb-devel.orig/drivers/usb/core/hub.c +++ usb-devel/drivers/usb/core/hub.c @@ -5721,6 +5721,13 @@ static int usb_reset_and_verify_device(s if (ret < 0) goto re_enumerate; + if (bos) + dev_info(&udev->dev, "Old BOS %p Len 0x%x\n", + bos, le16_to_cpu(bos->desc->wTotalLength)); + if (udev->bos) + dev_info(&udev->dev, "New BOS %p Len 0x%x\n", + udev->bos, le16_to_cpu(udev->bos->desc->wTotalLength)); + /* Device might have changed firmware (DFU or similar) */ if (descriptors_changed(udev, &descriptor, bos)) { dev_info(&udev->dev, "device firmware changed\n");
