Hi! I've got the following crash while fuzzing the kernel with syzkaller. On commit ebb2c2437d8008d46796902ff390653822af6cc4 (Sep 18). It seems there's no proper size check of a USB_DT_INTERFACE_ASSOCIATION descriptor. It's only checked that the size is >= 2 in usb_parse_configuration(), so find_iad() might do out-of-bounds access to intf_assoc->bInterfaceCount. gadgetfs: bound to dummy_udc driver usb 1-1: new full-speed USB device number 2 using dummy_hcd gadgetfs: connected gadgetfs: disconnected gadgetfs: connected usb 1-1: config 1 interface 0 altsetting 0 has an invalid endpoint with address 0x0, skipping usb 1-1: New USB device found, idVendor=0020, idProduct=410e usb 1-1: New USB device strings: Mfr=0, Product=8, SerialNumber=3 usb 1-1: Product: a usb 1-1: SerialNumber: a ================================================================== BUG: KASAN: slab-out-of-bounds in usb_set_configuration+0x1859/0x1870 Read of size 1 at addr ffff88006a9d00de by task kworker/0:2/1260 CPU: 0 PID: 1260 Comm: kworker/0:2 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 find_iad drivers/usb/core/message.c:1644 usb_set_configuration+0x1859/0x1870 drivers/usb/core/message.c:1855 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 1260: 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 2870: 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 load_elf_binary+0x39c2/0x4fa0 fs/binfmt_elf.c:1087 search_binary_handler+0x146/0x480 fs/exec.c:1634 exec_binprm fs/exec.c:1676 do_execveat_common.isra.31+0x16d2/0x2200 fs/exec.c:1798 do_execve fs/exec.c:1842 SYSC_execve fs/exec.c:1923 SyS_execve+0x3e/0x50 fs/exec.c:1918 do_syscall_64+0x2c5/0x830 arch/x86/entry/common.c:287 return_from_SYSCALL_64+0x0/0x7a arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88006a9d00c0 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 30 bytes inside of 32-byte region [ffff88006a9d00c0, ffff88006a9d00e0) The buggy address belongs to the page: page:ffffea0001aa7400 count:1 mapcount:0 mapping: (null) index:0xffff88006a9d05a0 flags: 0x100000000000100(slab) raw: 0100000000000100 0000000000000000 ffff88006a9d05a0 0000000180550054 raw: ffffea000193fa00 0000001400000014 ffff88006c403980 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88006a9cff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88006a9d0000: fb fb fb fb fc fc fb fb fb fb fc fc fb fb fb fb >ffff88006a9d0080: fc fc fb fb fb fb fc fc 00 00 00 05 fc fc fb fb ^ ffff88006a9d0100: fb fb fc fc fb fb fb fb fc fc fb fb fb fb fc fc ffff88006a9d0180: 00 00 00 00 fc fc 00 00 00 00 fc fc fb fb fb fb ================================================================== -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a 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