• Bjørn Mork's avatar
    net: qmi_wwan: fix divide by 0 on bad descriptors · 7fd07833
    Bjørn Mork authored
    A CDC Ethernet functional descriptor with wMaxSegmentSize = 0 will
    cause a divide error in usbnet_probe:
    
    divide error: 0000 [#1] PREEMPT SMP KASAN
    Modules linked in:
    CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.14.0-rc8-44453-g1fdc1a82c34f #56
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    Workqueue: usb_hub_wq hub_event
    task: ffff88006bef5c00 task.stack: ffff88006bf60000
    RIP: 0010:usbnet_update_max_qlen+0x24d/0x390 drivers/net/usb/usbnet.c:355
    RSP: 0018:ffff88006bf67508 EFLAGS: 00010246
    RAX: 00000000000163c8 RBX: ffff8800621fce40 RCX: ffff8800621fcf34
    RDX: 0000000000000000 RSI: ffffffff837ecb7a RDI: ffff8800621fcf34
    RBP: ffff88006bf67520 R08: ffff88006bef5c00 R09: ffffed000c43f881
    R10: ffffed000c43f880 R11: ffff8800621fc406 R12: 0000000000000003
    R13: ffffffff85c71de0 R14: 0000000000000000 R15: 0000000000000000
    FS:  0000000000000000(0000) GS:ffff88006ca00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007ffe9c0d6dac CR3: 00000000614f4000 CR4: 00000000000006f0
    Call Trace:
     usbnet_probe+0x18b5/0x2790 drivers/net/usb/usbnet.c:1783
     qmi_wwan_probe+0x133/0x220 drivers/net/usb/qmi_wwan.c:1338
     usb_probe_interface+0x324/0x940 drivers/usb/core/driver.c:361
     really_probe drivers/base/dd.c:413
     driver_probe_device+0x522/0x740 drivers/base/dd.c:557
    
    Fix by simply ignoring the bogus descriptor, as it is optional
    for QMI devices anyway.
    
    Fixes: 423ce8ca ("net: usb: qmi_wwan: New driver for Huawei QMI based WWAN devices")
    Reported-by: default avatarAndrey Konovalov <andreyknvl@google.com>
    Signed-off-by: default avatarBjørn Mork <bjorn@mork.no>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    7fd07833
qmi_wwan.c 46.6 KB