On Tue, Aug 20, 2019 at 10:00 PM Alan Stern <st...@rowland.harvard.edu> wrote:
>
> The syzbot fuzzer found a general protection fault in the HID subsystem:
>
> kasan: CONFIG_KASAN_INLINE enabled
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> general protection fault: 0000 [#1] SMP KASAN
> CPU: 0 PID: 3715 Comm: syz-executor.3 Not tainted 5.2.0-rc6+ #15
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:__pm_runtime_resume+0x49/0x180 drivers/base/power/runtime.c:1069
> Code: ed 74 d5 fe 45 85 ed 0f 85 9a 00 00 00 e8 6f 73 d5 fe 48 8d bd c1 02
> 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48
> 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 fe 00 00 00
> RSP: 0018:ffff8881d99d78e0 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: 0000000000000020 RCX: ffffc90003f3f000
> RDX: 0000000416d8686d RSI: ffffffff82676841 RDI: 00000020b6c3436a
> RBP: 00000020b6c340a9 R08: ffff8881c6d64800 R09: fffffbfff0e84c25
> R10: ffff8881d99d7940 R11: ffffffff87426127 R12: 0000000000000004
> R13: 0000000000000000 R14: ffff8881d9b94000 R15: ffffffff897f9048
> FS: 00007f047f542700(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b30f21000 CR3: 00000001ca032000 CR4: 00000000001406f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> pm_runtime_get_sync include/linux/pm_runtime.h:226 [inline]
> usb_autopm_get_interface+0x1b/0x50 drivers/usb/core/driver.c:1707
> usbhid_power+0x7c/0xe0 drivers/hid/usbhid/hid-core.c:1234
> hid_hw_power include/linux/hid.h:1038 [inline]
> hidraw_open+0x20d/0x740 drivers/hid/hidraw.c:282
> chrdev_open+0x219/0x5c0 fs/char_dev.c:413
> do_dentry_open+0x497/0x1040 fs/open.c:778
> do_last fs/namei.c:3416 [inline]
> path_openat+0x1430/0x3ff0 fs/namei.c:3533
> do_filp_open+0x1a1/0x280 fs/namei.c:3563
> do_sys_open+0x3c0/0x580 fs/open.c:1070
> do_syscall_64+0xb7/0x560 arch/x86/entry/common.c:301
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> It turns out the fault was caused by a bug in the HID Logitech driver,
> which violates the requirement that every pathway calling
> hid_hw_start() must also call hid_hw_stop(). This patch fixes the bug
> by making sure the requirement is met.
>
> Reported-and-tested-by: syzbot+3cbe5cd105d2ad56a...@syzkaller.appspotmail.com
> Signed-off-by: Alan Stern <st...@rowland.harvard.edu>
> CC: <sta...@vger.kernel.org>
This bug has manifested in a bunch of different ways and produced
multiple confusing syzbot reports. Thank you for tracking this down
and fixing it, Alan!
>
> ---
>
> [as1909]
>
>
> drivers/hid/hid-lg.c | 10 ++++++----
> drivers/hid/hid-lg4ff.c | 1 -
> 2 files changed, 6 insertions(+), 5 deletions(-)
>
> Index: usb-devel/drivers/hid/hid-lg.c
> ===================================================================
> --- usb-devel.orig/drivers/hid/hid-lg.c
> +++ usb-devel/drivers/hid/hid-lg.c
> @@ -818,7 +818,7 @@ static int lg_probe(struct hid_device *h
>
> if (!buf) {
> ret = -ENOMEM;
> - goto err_free;
> + goto err_stop;
> }
>
> ret = hid_hw_raw_request(hdev, buf[0], buf, sizeof(cbuf),
> @@ -850,9 +850,12 @@ static int lg_probe(struct hid_device *h
> ret = lg4ff_init(hdev);
>
> if (ret)
> - goto err_free;
> + goto err_stop;
>
> return 0;
> +
> +err_stop:
> + hid_hw_stop(hdev);
> err_free:
> kfree(drv_data);
> return ret;
> @@ -863,8 +866,7 @@ static void lg_remove(struct hid_device
> struct lg_drv_data *drv_data = hid_get_drvdata(hdev);
> if (drv_data->quirks & LG_FF4)
> lg4ff_deinit(hdev);
> - else
> - hid_hw_stop(hdev);
> + hid_hw_stop(hdev);
> kfree(drv_data);
> }
>
> Index: usb-devel/drivers/hid/hid-lg4ff.c
> ===================================================================
> --- usb-devel.orig/drivers/hid/hid-lg4ff.c
> +++ usb-devel/drivers/hid/hid-lg4ff.c
> @@ -1477,7 +1477,6 @@ int lg4ff_deinit(struct hid_device *hid)
> }
> }
> #endif
> - hid_hw_stop(hid);
> drv_data->device_props = NULL;
>
> kfree(entry);
>
