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From:   Andrey Konovalov <andreyknvl@google.com>
Date:   Fri, 19 Jun 2020 18:10:07 +0200
Message-ID: <CAAeHK+xT12YpnLYw78RVS5PAFK=yFnYNhq0vny7C2O+zUsFwdg@mail.gmail.com>
Subject: Re: KASAN: use-after-free Read in uvc_probe
To:     syzbot <syzbot+9a48339b077c5a80b869@syzkaller.appspotmail.com>
Cc:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        LKML <linux-kernel@vger.kernel.org>, linux-media@vger.kernel.org,
        USB list <linux-usb@vger.kernel.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
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On Mon, Jan 13, 2020 at 1:24 PM syzbot
<syzbot+9a48339b077c5a80b869@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    ae179410 usb: gadget: add raw-gadget interface
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=132223fee00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ad1d751a3a72ae57
> dashboard link: https://syzkaller.appspot.com/bug?extid=9a48339b077c5a80b869
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16857325e00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142e069ee00000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+9a48339b077c5a80b869@syzkaller.appspotmail.com
>
> usb 1-1: New USB device found, idVendor=0bd3, idProduct=0555,
> bcdDevice=69.6a
> usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
> usb 1-1: config 0 descriptor??
> usb 1-1: string descriptor 0 read error: -71
> uvcvideo: Found UVC 0.00 device <unnamed> (0bd3:0555)
> ==================================================================
> BUG: KASAN: use-after-free in uvc_register_terms
> drivers/media/usb/uvc/uvc_driver.c:2038 [inline]
> BUG: KASAN: use-after-free in uvc_register_chains
> drivers/media/usb/uvc/uvc_driver.c:2070 [inline]
> BUG: KASAN: use-after-free in uvc_probe.cold+0x2193/0x29de
> drivers/media/usb/uvc/uvc_driver.c:2201
> Read of size 2 at addr ffff8881d4f1bc2e by task kworker/1:2/94
>
> CPU: 1 PID: 94 Comm: kworker/1:2 Not tainted 5.5.0-rc3-syzkaller #0
> 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+0xef/0x16e lib/dump_stack.c:118
>   print_address_description.constprop.0.cold+0xd3/0x314 mm/kasan/report.c:374
>   __kasan_report.cold+0x37/0x85 mm/kasan/report.c:506
>   kasan_report+0xe/0x20 mm/kasan/common.c:639
>   uvc_register_terms drivers/media/usb/uvc/uvc_driver.c:2038 [inline]
>   uvc_register_chains drivers/media/usb/uvc/uvc_driver.c:2070 [inline]
>   uvc_probe.cold+0x2193/0x29de drivers/media/usb/uvc/uvc_driver.c:2201
>   usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:361
>   really_probe+0x290/0xad0 drivers/base/dd.c:548
>   driver_probe_device+0x223/0x350 drivers/base/dd.c:721
>   __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
>   __device_attach+0x217/0x390 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
>   device_add+0x1459/0x1bf0 drivers/base/core.c:2487
>   usb_set_configuration+0xe47/0x17d0 drivers/usb/core/message.c:2023
>   generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
>   usb_probe_device+0xaf/0x140 drivers/usb/core/driver.c:266
>   really_probe+0x290/0xad0 drivers/base/dd.c:548
>   driver_probe_device+0x223/0x350 drivers/base/dd.c:721
>   __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
>   __device_attach+0x217/0x390 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
>   device_add+0x1459/0x1bf0 drivers/base/core.c:2487
>   usb_new_device.cold+0x540/0xcd0 drivers/usb/core/hub.c:2537
>   hub_port_connect drivers/usb/core/hub.c:5184 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
>   port_event drivers/usb/core/hub.c:5470 [inline]
>   hub_event+0x21cb/0x4300 drivers/usb/core/hub.c:5552
>   process_one_work+0x945/0x15c0 kernel/workqueue.c:2264
>   worker_thread+0x96/0xe20 kernel/workqueue.c:2410
>   kthread+0x318/0x420 kernel/kthread.c:255
>   ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
>
> Allocated by task 94:
>   save_stack+0x1b/0x80 mm/kasan/common.c:72
>   set_track mm/kasan/common.c:80 [inline]
>   __kasan_kmalloc mm/kasan/common.c:513 [inline]
>   __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:486
>   kmalloc include/linux/slab.h:556 [inline]
>   kzalloc include/linux/slab.h:670 [inline]
>   uvc_alloc_chain+0x48/0xfa drivers/media/usb/uvc/uvc_driver.c:1692
>   uvc_scan_device drivers/media/usb/uvc/uvc_driver.c:1818 [inline]
>   uvc_probe.cold+0x15f0/0x29de drivers/media/usb/uvc/uvc_driver.c:2197
>   usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:361
>   really_probe+0x290/0xad0 drivers/base/dd.c:548
>   driver_probe_device+0x223/0x350 drivers/base/dd.c:721
>   __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
>   __device_attach+0x217/0x390 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
>   device_add+0x1459/0x1bf0 drivers/base/core.c:2487
>   usb_set_configuration+0xe47/0x17d0 drivers/usb/core/message.c:2023
>   generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
>   usb_probe_device+0xaf/0x140 drivers/usb/core/driver.c:266
>   really_probe+0x290/0xad0 drivers/base/dd.c:548
>   driver_probe_device+0x223/0x350 drivers/base/dd.c:721
>   __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
>   __device_attach+0x217/0x390 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
>   device_add+0x1459/0x1bf0 drivers/base/core.c:2487
>   usb_new_device.cold+0x540/0xcd0 drivers/usb/core/hub.c:2537
>   hub_port_connect drivers/usb/core/hub.c:5184 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
>   port_event drivers/usb/core/hub.c:5470 [inline]
>   hub_event+0x21cb/0x4300 drivers/usb/core/hub.c:5552
>   process_one_work+0x945/0x15c0 kernel/workqueue.c:2264
>   worker_thread+0x96/0xe20 kernel/workqueue.c:2410
>   kthread+0x318/0x420 kernel/kthread.c:255
>   ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
>
> Freed by task 94:
>   save_stack+0x1b/0x80 mm/kasan/common.c:72
>   set_track mm/kasan/common.c:80 [inline]
>   kasan_set_free_info mm/kasan/common.c:335 [inline]
>   __kasan_slab_free+0x117/0x160 mm/kasan/common.c:474
>   slab_free_hook mm/slub.c:1425 [inline]
>   slab_free_freelist_hook mm/slub.c:1458 [inline]
>   slab_free mm/slub.c:3005 [inline]
>   kfree+0xd5/0x300 mm/slub.c:3957
>   uvc_scan_device drivers/media/usb/uvc/uvc_driver.c:1825 [inline]
>   uvc_probe.cold+0x16fd/0x29de drivers/media/usb/uvc/uvc_driver.c:2197
>   usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:361
>   really_probe+0x290/0xad0 drivers/base/dd.c:548
>   driver_probe_device+0x223/0x350 drivers/base/dd.c:721
>   __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
>   __device_attach+0x217/0x390 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
>   device_add+0x1459/0x1bf0 drivers/base/core.c:2487
>   usb_set_configuration+0xe47/0x17d0 drivers/usb/core/message.c:2023
>   generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
>   usb_probe_device+0xaf/0x140 drivers/usb/core/driver.c:266
>   really_probe+0x290/0xad0 drivers/base/dd.c:548
>   driver_probe_device+0x223/0x350 drivers/base/dd.c:721
>   __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
>   __device_attach+0x217/0x390 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
>   device_add+0x1459/0x1bf0 drivers/base/core.c:2487
>   usb_new_device.cold+0x540/0xcd0 drivers/usb/core/hub.c:2537
>   hub_port_connect drivers/usb/core/hub.c:5184 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
>   port_event drivers/usb/core/hub.c:5470 [inline]
>   hub_event+0x21cb/0x4300 drivers/usb/core/hub.c:5552
>   process_one_work+0x945/0x15c0 kernel/workqueue.c:2264
>   worker_thread+0x96/0xe20 kernel/workqueue.c:2410
>   kthread+0x318/0x420 kernel/kthread.c:255
>   ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
>
> The buggy address belongs to the object at ffff8881d4f1bc00
>   which belongs to the cache kmalloc-256 of size 256
> The buggy address is located 46 bytes inside of
>   256-byte region [ffff8881d4f1bc00, ffff8881d4f1bd00)
> The buggy address belongs to the page:
> page:ffffea000753c680 refcount:1 mapcount:0 mapping:ffff8881da002780
> index:0x0 compound_mapcount: 0
> raw: 0200000000010200 ffffea000753c600 0000000300000003 ffff8881da002780
> raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>   ffff8881d4f1bb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>   ffff8881d4f1bb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > ffff8881d4f1bc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                    ^
>   ffff8881d4f1bc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>   ffff8881d4f1bd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this bug, for details see:
> https://goo.gl/tpsmEJ#testing-patches

Fixed by something.

#syz invalid