Re: [PATCH] usbhid: fix array-index-out-of-bounds in usbhid_parse UBSAN warning

From: Dan Carpenter
Date: Wed Jan 03 2024 - 09:13:08 EST


Hi syzbot,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/syzbot/usbhid-fix-array-index-out-of-bounds-in-usbhid_parse-UBSAN-warning/20231225-153341
base: https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git for-next
patch link: https://lore.kernel.org/r/0000000000009ae37b060d32c643%40google.com
patch subject: [PATCH] usbhid: fix array-index-out-of-bounds in usbhid_parse UBSAN warning
config: x86_64-randconfig-161-20231225 (https://download.01.org/0day-ci/archive/20231226/202312260900.gRDPofL9-lkp@xxxxxxxxx/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202312260900.gRDPofL9-lkp@xxxxxxxxx/

smatch warnings:
drivers/hid/usbhid/hid-core.c:1026 usbhid_parse() warn: curly braces intended?
drivers/hid/usbhid/hid-core.c:1029 usbhid_parse() warn: inconsistent indenting

vim +1026 drivers/hid/usbhid/hid-core.c

c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 979 static int usbhid_parse(struct hid_device *hid)
c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 980 {
c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 981 struct usb_interface *intf = to_usb_interface(hid->dev.parent);
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 982 struct usb_host_interface *interface = intf->cur_altsetting;
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 983 struct usb_device *dev = interface_to_usbdev (intf);
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 984 struct hid_descriptor *hdesc;
2eb5dc30eb87aa drivers/hid/usbhid/hid-core.c Paul Walmsley 2007-04-19 985 u32 quirks = 0;
c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 986 unsigned int rsize = 0;
c5b7c7c395a34f drivers/usb/input/hid-core.c Dmitry Torokhov 2005-09-15 987 char *rdesc;
c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 988 int ret, n;
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 989 int num_descriptors;
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 990 size_t offset = offsetof(struct hid_descriptor, desc);
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 991
d5d3e202753cc0 drivers/hid/usbhid/hid-core.c Benjamin Tissoires 2017-11-20 992 quirks = hid_lookup_quirk(hid);
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 993
6f4303fb2ec680 drivers/hid/usbhid/hid-core.c Jiri Kosina 2009-01-29 994 if (quirks & HID_QUIRK_IGNORE)
6f4303fb2ec680 drivers/hid/usbhid/hid-core.c Jiri Kosina 2009-01-29 995 return -ENODEV;
6f4303fb2ec680 drivers/hid/usbhid/hid-core.c Jiri Kosina 2009-01-29 996
0f28b55db54300 drivers/usb/input/hid-core.c Alan Stern 2006-05-15 997 /* Many keyboards and mice don't like to be polled for reports,
0f28b55db54300 drivers/usb/input/hid-core.c Alan Stern 2006-05-15 998 * so we will always set the HID_QUIRK_NOGET flag for them. */
0f28b55db54300 drivers/usb/input/hid-core.c Alan Stern 2006-05-15 999 if (interface->desc.bInterfaceSubClass == USB_INTERFACE_SUBCLASS_BOOT) {
0f28b55db54300 drivers/usb/input/hid-core.c Alan Stern 2006-05-15 1000 if (interface->desc.bInterfaceProtocol == USB_INTERFACE_PROTOCOL_KEYBOARD ||
0f28b55db54300 drivers/usb/input/hid-core.c Alan Stern 2006-05-15 1001 interface->desc.bInterfaceProtocol == USB_INTERFACE_PROTOCOL_MOUSE)
0f28b55db54300 drivers/usb/input/hid-core.c Alan Stern 2006-05-15 1002 quirks |= HID_QUIRK_NOGET;
0f28b55db54300 drivers/usb/input/hid-core.c Alan Stern 2006-05-15 1003 }
0f28b55db54300 drivers/usb/input/hid-core.c Alan Stern 2006-05-15 1004
c5b7c7c395a34f drivers/usb/input/hid-core.c Dmitry Torokhov 2005-09-15 1005 if (usb_get_extra_descriptor(interface, HID_DT_HID, &hdesc) &&
c5b7c7c395a34f drivers/usb/input/hid-core.c Dmitry Torokhov 2005-09-15 1006 (!interface->desc.bNumEndpoints ||
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 1007 usb_get_extra_descriptor(&interface->endpoint[0], HID_DT_HID, &hdesc))) {
58037eb961f859 drivers/hid/usbhid/hid-core.c Jiri Kosina 2007-05-30 1008 dbg_hid("class descriptor not present\n");
c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 1009 return -ENODEV;
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 1010 }
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 1011
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 1012 if (hdesc->bLength < sizeof(struct hid_descriptor)) {
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 1013 dbg_hid("hid descriptor is too short\n");
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 1014 return -EINVAL;
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 1015 }
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 1016
c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 1017 hid->version = le16_to_cpu(hdesc->bcdHID);
c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 1018 hid->country = hdesc->bCountryCode;
c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 1019
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 1020 num_descriptors = min_t(int, hdesc->bNumDescriptors,
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 1021 (hdesc->bLength - offset) / sizeof(struct hid_class_descriptor));
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 1022
f043bfc98c193c drivers/hid/usbhid/hid-core.c Jaejoong Kim 2017-09-28 1023 for (n = 0; n < num_descriptors; n++)

This for loop needs curly braces now.

d3e0d5b253c73b drivers/hid/usbhid/hid-core.c syzbot 2023-12-23 1024 if (n >= ARRAY_SIZE(hdesc->desc))
d3e0d5b253c73b drivers/hid/usbhid/hid-core.c syzbot 2023-12-23 1025 break;
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 @1026 if (hdesc->desc[n].bDescriptorType == HID_DT_REPORT)
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 1027 rsize = le16_to_cpu(hdesc->desc[n].wDescriptorLength);
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 1028
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 @1029 if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
58037eb961f859 drivers/hid/usbhid/hid-core.c Jiri Kosina 2007-05-30 1030 dbg_hid("weird size of report descriptor (%u)\n", rsize);
c500c9714011ed drivers/hid/usbhid/hid-core.c Jiri Slaby 2008-05-16 1031 return -EINVAL;
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 1032 }
^1da177e4c3f41 drivers/usb/input/hid-core.c Linus Torvalds 2005-04-16 1033
52150c78270db5 drivers/hid/usbhid/hid-core.c Joe Perches 2017-03-01 1034 rdesc = kmalloc(rsize, GFP_KERNEL);

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