Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967461AbdIZHb7 (ORCPT ); Tue, 26 Sep 2017 03:31:59 -0400 Received: from mail-pg0-f67.google.com ([74.125.83.67]:36880 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935108AbdIZHb4 (ORCPT ); Tue, 26 Sep 2017 03:31:56 -0400 X-Google-Smtp-Source: AOwi7QC5LsTDheNcXqY1pNK0VDtgpzvbK3YQLCblCSmjz1oX9gRUqZTntJ7OKZps/TgiiUtZPdmomQ== From: Jaejoong Kim To: Alan Stern , Jiri Kosina Cc: Andrey Konovalov , Benjamin Tissoires , USB list , linux-input@vger.kernel.org, LKML , syzkaller , Dmitry Vyukov , Kostya Serebryany , Jaejoong Kim Subject: [PATCH] HID: usbhid: fix out-of-bounds bug Date: Tue, 26 Sep 2017 16:31:24 +0900 Message-Id: <1506411084-7324-1-git-send-email-climbbb.kim@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8908 Lines: 213 The starting address of the hid descriptor is obtained via usb_get_extra_descriptor(). If the hid descriptor has the wrong size, it is possible to access the wrong address. So, before accessing the hid descriptor, we need to check the entire size through the bLength field. It also shows how many class descriptors it has through the bNumDescriptors of the hid descriptor. Assuming that the connected hid descriptor has two class descriptors(report and physical descriptors), the code below can cause OOB because hdesc->desc is an array of size 1. for (n = 0; n < hdesc->bNumDescriptors; n++) if (hdesc->desc[n].bDescriptorType == HID_DT_REPORT) rsize = le16_to_cpu(hdesc->desc[n].wDescriptorLength); Since we know the starting address of the hid descriptor and the value of the bNumDescriptors is variable, we directly access the buffer containing the hid descriptor without usbing hdesc->desc to obtain the size of the report descriptor. ================================================================== 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 ================================================================== Reported-by: Alexander Potapenko Signed-off-by: Jaejoong Kim --- drivers/hid/usbhid/hid-core.c | 39 +++++++++++++++++++++++++++------------ include/linux/hid.h | 2 ++ 2 files changed, 29 insertions(+), 12 deletions(-) diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c index 089bad8..7bad173 100644 --- a/drivers/hid/usbhid/hid-core.c +++ b/drivers/hid/usbhid/hid-core.c @@ -970,12 +970,19 @@ static int usbhid_parse(struct hid_device *hid) struct usb_interface *intf = to_usb_interface(hid->dev.parent); struct usb_host_interface *interface = intf->cur_altsetting; struct usb_device *dev = interface_to_usbdev (intf); - struct hid_descriptor *hdesc; + unsigned char *buffer = intf->altsetting->extra; + int buflen = intf->altsetting->extralen; + int length; u32 quirks = 0; unsigned int rsize = 0; char *rdesc; int ret, n; + if (!buffer) { + dbg_hid("class descriptor not present\n"); + return -ENODEV; + } + quirks = usbhid_lookup_quirk(le16_to_cpu(dev->descriptor.idVendor), le16_to_cpu(dev->descriptor.idProduct)); @@ -990,19 +997,27 @@ static int usbhid_parse(struct hid_device *hid) quirks |= HID_QUIRK_NOGET; } - if (usb_get_extra_descriptor(interface, HID_DT_HID, &hdesc) && - (!interface->desc.bNumEndpoints || - usb_get_extra_descriptor(&interface->endpoint[0], HID_DT_HID, &hdesc))) { - dbg_hid("class descriptor not present\n"); - return -ENODEV; - } + while (buflen > 2) { + length = buffer[0]; + if (!length || length < HID_DESCRIPTOR_MIN_SIZE) + goto next_desc; - hid->version = le16_to_cpu(hdesc->bcdHID); - hid->country = hdesc->bCountryCode; + if (buffer[1] == HID_DT_HID) { + hid->version = get_unaligned_le16(&buffer[2]); + hid->country = buffer[4]; - for (n = 0; n < hdesc->bNumDescriptors; n++) - if (hdesc->desc[n].bDescriptorType == HID_DT_REPORT) - rsize = le16_to_cpu(hdesc->desc[n].wDescriptorLength); + for (n = 0; n < buffer[5]; n++) { + /* we are just interested in report descriptor */ + if (buffer[6+3*n] != HID_DT_REPORT) + continue; + rsize = get_unaligned_le16(&buffer[7+3*n]); + } + } + +next_desc: + buflen -= length; + buffer += length; + } if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) { dbg_hid("weird size of report descriptor (%u)\n", rsize); diff --git a/include/linux/hid.h b/include/linux/hid.h index ab05a86..2d53c0f 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -638,6 +638,8 @@ struct hid_descriptor { struct hid_class_descriptor desc[1]; } __attribute__ ((packed)); +#define HID_DESCRIPTOR_MIN_SIZE 9 + #define HID_DEVICE(b, g, ven, prod) \ .bus = (b), .group = (g), .vendor = (ven), .product = (prod) #define HID_USB_DEVICE(ven, prod) \ -- 2.7.4