On Tue, Sep 19, 2017 at 1:47 PM, Kim Jaejoong <climbbb.kim@xxxxxxxxx> wrote: > Hi, Andrey Konovalov > > Thanks for the report. > > 2017-09-19 2:33 GMT+09:00 Andrey Konovalov <andreyknvl@xxxxxxxxxx>: >> Hi! >> >> I've got the following crash while fuzzing the kernel with syzkaller. >> >> On commit ebb2c2437d8008d46796902ff390653822af6cc4 (Sep 18). >> >> It seems that there's no proper check on the hdesc->bNumDescriptors >> value in usbhid_parse(). it iterates over hdesc->desc and accesses >> hdesc->desc[n] fields, which might be out-of-bounds. > > The bNumDescriptors in hid descriptor means 'numeric expression > specifying the number of class descriptors'. > The value bNumberDescriptors identifies the number of additional class > specific descriptors present. > (refer to the 6.1.2 HID Descriptor in hid documents : > http://www.usb.org/developers/hidpage/HID1_11.pdf) > > So, it can be out-of-bounds in hdesc->desc[n] if there is an > additional class descriptor. > > Does the patch below fix this? Hi Kim, I'm not sure. Is there a check on the bLength field of a hid_descriptor struct? Can it be less than sizeof(struct hid_descriptor)? If so, we still do an out-of-bounds access to hdesc->desc[0] (or some other fields). Thanks! > > Thanks, jaejoong > ------ > > diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c > index 089bad8..7b6a0b6 100644 > --- a/drivers/hid/usbhid/hid-core.c > +++ b/drivers/hid/usbhid/hid-core.c > @@ -974,7 +974,7 @@ static int usbhid_parse(struct hid_device *hid) > u32 quirks = 0; > unsigned int rsize = 0; > char *rdesc; > - int ret, n; > + int ret; > > quirks = usbhid_lookup_quirk(le16_to_cpu(dev->descriptor.idVendor), > le16_to_cpu(dev->descriptor.idProduct)); > @@ -1000,9 +1000,8 @@ static int usbhid_parse(struct hid_device *hid) > hid->version = le16_to_cpu(hdesc->bcdHID); > hid->country = hdesc->bCountryCode; > > - for (n = 0; n < hdesc->bNumDescriptors; n++) > - if (hdesc->desc[n].bDescriptorType == HID_DT_REPORT) > - rsize = le16_to_cpu(hdesc->desc[n].wDescriptorLength); > + if (hdesc->desc[0].bDescriptorType == HID_DT_REPORT) > + rsize = le16_to_cpu(hdesc->desc[0].wDescriptorLength); > > if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) { > dbg_hid("weird size of report descriptor (%u)\n", rsize); > > >> >> ================================================================== >> BUG: KASAN: slab-out-of-bounds in usbhid_parse+0x9b1/0xa20 >> Read of size 1 at addr ffff88006c5f8edf by task kworker/1:2/1261 >> >> CPU: 1 PID: 1261 Comm: kworker/1:2 Not tainted >> 4.14.0-rc1-42251-gebb2c2437d80 #169 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 >> Workqueue: usb_hub_wq hub_event >> Call Trace: >> __dump_stack lib/dump_stack.c:16 >> dump_stack+0x292/0x395 lib/dump_stack.c:52 >> print_address_description+0x78/0x280 mm/kasan/report.c:252 >> kasan_report_error mm/kasan/report.c:351 >> kasan_report+0x22f/0x340 mm/kasan/report.c:409 >> __asan_report_load1_noabort+0x19/0x20 mm/kasan/report.c:427 >> usbhid_parse+0x9b1/0xa20 drivers/hid/usbhid/hid-core.c:1004 >> hid_add_device+0x16b/0xb30 drivers/hid/hid-core.c:2944 >> usbhid_probe+0xc28/0x1100 drivers/hid/usbhid/hid-core.c:1369 >> usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361 >> really_probe drivers/base/dd.c:413 >> driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 >> __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 >> bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 >> __device_attach+0x26e/0x3d0 drivers/base/dd.c:710 >> device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 >> bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 >> device_add+0xd0b/0x1660 drivers/base/core.c:1835 >> usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932 >> generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174 >> usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266 >> really_probe drivers/base/dd.c:413 >> driver_probe_device+0x610/0xa00 drivers/base/dd.c:557 >> __device_attach_driver+0x230/0x290 drivers/base/dd.c:653 >> bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463 >> __device_attach+0x26e/0x3d0 drivers/base/dd.c:710 >> device_initial_probe+0x1f/0x30 drivers/base/dd.c:757 >> bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523 >> device_add+0xd0b/0x1660 drivers/base/core.c:1835 >> usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457 >> hub_port_connect drivers/usb/core/hub.c:4903 >> hub_port_connect_change drivers/usb/core/hub.c:5009 >> port_event drivers/usb/core/hub.c:5115 >> hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195 >> process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119 >> worker_thread+0x221/0x1850 kernel/workqueue.c:2253 >> kthread+0x3a1/0x470 kernel/kthread.c:231 >> ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 >> >> Allocated by task 1261: >> save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59 >> save_stack+0x43/0xd0 mm/kasan/kasan.c:447 >> set_track mm/kasan/kasan.c:459 >> kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 >> __kmalloc+0x14e/0x310 mm/slub.c:3782 >> kmalloc ./include/linux/slab.h:498 >> usb_get_configuration+0x372/0x2a60 drivers/usb/core/config.c:848 >> usb_enumerate_device drivers/usb/core/hub.c:2290 >> usb_new_device+0xaae/0x1020 drivers/usb/core/hub.c:2426 >> hub_port_connect drivers/usb/core/hub.c:4903 >> hub_port_connect_change drivers/usb/core/hub.c:5009 >> port_event drivers/usb/core/hub.c:5115 >> hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195 >> process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119 >> worker_thread+0x221/0x1850 kernel/workqueue.c:2253 >> kthread+0x3a1/0x470 kernel/kthread.c:231 >> ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 >> >> Freed by task 2927: >> save_stack_trace+0x1b/0x20 arch/x86/kernel/stacktrace.c:59 >> save_stack+0x43/0xd0 mm/kasan/kasan.c:447 >> set_track mm/kasan/kasan.c:459 >> kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:524 >> slab_free_hook mm/slub.c:1390 >> slab_free_freelist_hook mm/slub.c:1412 >> slab_free mm/slub.c:2988 >> kfree+0xf6/0x2f0 mm/slub.c:3919 >> free_rb_tree_fname+0x8a/0xe0 fs/ext4/dir.c:402 >> ext4_htree_free_dir_info fs/ext4/dir.c:424 >> ext4_release_dir+0x49/0x70 fs/ext4/dir.c:622 >> __fput+0x33e/0x800 fs/file_table.c:210 >> ____fput+0x1a/0x20 fs/file_table.c:244 >> task_work_run+0x1af/0x280 kernel/task_work.c:112 >> tracehook_notify_resume ./include/linux/tracehook.h:191 >> exit_to_usermode_loop+0x1e1/0x220 arch/x86/entry/common.c:162 >> prepare_exit_to_usermode arch/x86/entry/common.c:197 >> syscall_return_slowpath+0x414/0x480 arch/x86/entry/common.c:266 >> entry_SYSCALL_64_fastpath+0xc0/0xc2 arch/x86/entry/entry_64.S:238 >> >> The buggy address belongs to the object at ffff88006c5f8ea0 >> which belongs to the cache kmalloc-64 of size 64 >> The buggy address is located 63 bytes inside of >> 64-byte region [ffff88006c5f8ea0, ffff88006c5f8ee0) >> The buggy address belongs to the page: >> page:ffffea0001b17e00 count:1 mapcount:0 mapping: (null) index:0x0 >> flags: 0x100000000000100(slab) >> raw: 0100000000000100 0000000000000000 0000000000000000 00000001002a002a >> raw: ffffea0001a83000 0000001500000015 ffff88006c403800 0000000000000000 >> page dumped because: kasan: bad access detected >> >> Memory state around the buggy address: >> ffff88006c5f8d80: fb fb fb fb fb fb fb fb fc fc fc fc 00 00 00 00 >> ffff88006c5f8e00: 00 fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >>>ffff88006c5f8e80: fc fc fc fc 00 00 00 00 00 00 00 07 fc fc fc fc >> ^ >> ffff88006c5f8f00: fb fb fb fb fb fb fb fb fc fc fc fc fb fb fb fb >> ffff88006c5f8f80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc >> ================================================================== >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-input" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > You received this message because you are subscribed to the Google Groups "syzkaller" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller+unsubscribe@xxxxxxxxxxxxxxxx. > For more options, visit https://groups.google.com/d/optout. -- To unsubscribe from this 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