usb/net/qmi_wwan: divide error in qmi_wwan_probe/usbnet_probe
Hi! I've got the following report while fuzzing the kernel with syzkaller. On commit 39dae59d66acd86d1de24294bd2f343fd5e7a625 (4.14-rc8). qmi_wwan 1-1:0.4: cdc-wdm0: USB WDM device divide error: [#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: 88006bef5c00 task.stack: 88006bf6 RIP: 0010:usbnet_update_max_qlen+0x24d/0x390 drivers/net/usb/usbnet.c:355 RSP: 0018:88006bf67508 EFLAGS: 00010246 RAX: 000163c8 RBX: 8800621fce40 RCX: 8800621fcf34 RDX: RSI: 837ecb7a RDI: 8800621fcf34 RBP: 88006bf67520 R08: 88006bef5c00 R09: ed000c43f881 R10: ed000c43f880 R11: 8800621fc406 R12: 0003 R13: 85c71de0 R14: R15: FS: () GS:88006ca0() knlGS: CS: 0010 DS: ES: CR0: 80050033 CR2: 7ffe9c0d6dac CR3: 614f4000 CR4: 06f0 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 __device_attach_driver+0x25d/0x2d0 drivers/base/dd.c:653 bus_for_each_drv+0xff/0x160 drivers/base/bus.c:463 __device_attach+0x1a8/0x2a0 drivers/base/dd.c:710 device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 bus_probe_device+0x1fc/0x2a0 drivers/base/bus.c:523 device_add+0xc27/0x15a0 drivers/base/core.c:1835 usb_set_configuration+0xd4f/0x17a0 drivers/usb/core/message.c:1932 generic_probe+0xbb/0x120 drivers/usb/core/generic.c:174 usb_probe_device+0xab/0x100 drivers/usb/core/driver.c:266 really_probe drivers/base/dd.c:413 driver_probe_device+0x522/0x740 drivers/base/dd.c:557 __device_attach_driver+0x25d/0x2d0 drivers/base/dd.c:653 bus_for_each_drv+0xff/0x160 drivers/base/bus.c:463 __device_attach+0x1a8/0x2a0 drivers/base/dd.c:710 device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 bus_probe_device+0x1fc/0x2a0 drivers/base/bus.c:523 device_add+0xc27/0x15a0 drivers/base/core.c:1835 usb_new_device+0x7fa/0x1090 drivers/usb/core/hub.c:2538 hub_port_connect drivers/usb/core/hub.c:4987 hub_port_connect_change drivers/usb/core/hub.c:5093 port_event drivers/usb/core/hub.c:5199 hub_event_impl+0x17b8/0x3440 drivers/usb/core/hub.c:5311 hub_event+0x38/0x50 drivers/usb/core/hub.c:5209 process_one_work+0x925/0x15d0 kernel/workqueue.c:2113 worker_thread+0xef/0x10d0 kernel/workqueue.c:2247 kthread+0x346/0x410 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:432 Code: b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 46 01 00 00 48 8d bb f4 00 00 00 31 d2 b8 c8 63 01 00 48 89 f9 <48> f7 b3 b0 01 00 00 48 ba 00 00 00 00 00 fc ff df 48 c1 e9 03 RIP: usbnet_update_max_qlen+0x24d/0x390 RSP: 88006bf67508 ---[ end trace 834034903d6f2b37 ]--- -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: usb/net/qmi_wwan: divide error in qmi_wwan_probe/usbnet_probe
Andrey Konovalov writes: > Hi! > > I've got the following report while fuzzing the kernel with syzkaller. Thanks. It would have helped a lot of you said *what* you were fuzzing, though But based on where the bug is, I assume it is USB descriptors? > On commit 39dae59d66acd86d1de24294bd2f343fd5e7a625 (4.14-rc8). > > qmi_wwan 1-1:0.4: cdc-wdm0: USB WDM device > divide error: [#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: 88006bef5c00 task.stack: 88006bf6 > RIP: 0010:usbnet_update_max_qlen+0x24d/0x390 drivers/net/usb/usbnet.c:355 > RSP: 0018:88006bf67508 EFLAGS: 00010246 > RAX: 000163c8 RBX: 8800621fce40 RCX: 8800621fcf34 > RDX: RSI: 837ecb7a RDI: 8800621fcf34 > RBP: 88006bf67520 R08: 88006bef5c00 R09: ed000c43f881 > R10: ed000c43f880 R11: 8800621fc406 R12: 0003 > R13: 85c71de0 R14: R15: > FS: () GS:88006ca0() knlGS: > CS: 0010 DS: ES: CR0: 80050033 > CR2: 7ffe9c0d6dac CR3: 614f4000 CR4: 06f0 > Call Trace: > usbnet_probe+0x18b5/0x2790 drivers/net/usb/usbnet.c:1783 > qmi_wwan_probe+0x133/0x220 drivers/net/usb/qmi_wwan.c:1338 So, looking over this again and again, the only obviously risky division I can see is the usbnet_update_max_qlen() call where we divide on both dev->rx_urb_size and dev->hard_mtu. I don't think dev->rx_urb_size can be 0 unless dev->hard_mtu is 0. But the latter is possible, and this is a bug. In qmi_wwan_bind(), which is called by usbnet_probe() prior to the usbnet_update_max_qlen() call, we do if (cdc_ether) { dev->hard_mtu = le16_to_cpu(cdc_ether->wMaxSegmentSize); usbnet_get_ethernet_addr(dev, cdc_ether->iMACAddress); } which will be fatal if cdc_ether->wMaxSegmentSize is 0. I assume that is what your fuzzer did? Fix coming up RSN. Thanks a lot for pointing this out. Bjørn -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: usb/net/qmi_wwan: divide error in qmi_wwan_probe/usbnet_probe
On Mon, Nov 6, 2017 at 3:06 PM, Bjørn Mork wrote: > Andrey Konovalov writes: > >> Hi! >> >> I've got the following report while fuzzing the kernel with syzkaller. > > Thanks. It would have helped a lot of you said *what* you were fuzzing, > though But based on where the bug is, I assume it is USB > descriptors? Yes, I was connecting USB devices with random descriptors. I though it's obvious from the stack trace, but I'll include that in the following reports. Thanks! > > >> On commit 39dae59d66acd86d1de24294bd2f343fd5e7a625 (4.14-rc8). >> >> qmi_wwan 1-1:0.4: cdc-wdm0: USB WDM device >> divide error: [#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: 88006bef5c00 task.stack: 88006bf6 >> RIP: 0010:usbnet_update_max_qlen+0x24d/0x390 drivers/net/usb/usbnet.c:355 >> RSP: 0018:88006bf67508 EFLAGS: 00010246 >> RAX: 000163c8 RBX: 8800621fce40 RCX: 8800621fcf34 >> RDX: RSI: 837ecb7a RDI: 8800621fcf34 >> RBP: 88006bf67520 R08: 88006bef5c00 R09: ed000c43f881 >> R10: ed000c43f880 R11: 8800621fc406 R12: 0003 >> R13: 85c71de0 R14: R15: >> FS: () GS:88006ca0() knlGS: >> CS: 0010 DS: ES: CR0: 80050033 >> CR2: 7ffe9c0d6dac CR3: 614f4000 CR4: 06f0 >> Call Trace: >> usbnet_probe+0x18b5/0x2790 drivers/net/usb/usbnet.c:1783 >> qmi_wwan_probe+0x133/0x220 drivers/net/usb/qmi_wwan.c:1338 > > So, looking over this again and again, the only obviously risky division > I can see is the usbnet_update_max_qlen() call where we divide on both > dev->rx_urb_size and dev->hard_mtu. > > I don't think dev->rx_urb_size can be 0 unless dev->hard_mtu is 0. But > the latter is possible, and this is a bug. In qmi_wwan_bind(), which is > called by usbnet_probe() prior to the usbnet_update_max_qlen() call, we > do > > if (cdc_ether) { > dev->hard_mtu = le16_to_cpu(cdc_ether->wMaxSegmentSize); > usbnet_get_ethernet_addr(dev, cdc_ether->iMACAddress); > } > > which will be fatal if cdc_ether->wMaxSegmentSize is 0. I assume that > is what your fuzzer did? Fix coming up RSN. Thanks a lot for pointing > this out. I don't see the crash with your patches. Thanks for a quick fix! > > > Bjørn -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html