Re: KASAN: use-after-free Write in ld_usb_interrupt_in_callback

[Andrey Konovalov <andreyknvl@google.com>]

On Mon, Aug 12, 2019 at 2:18 PM syzbot
<syzbot+a4b088ebfbadf5f82150@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    e96407b4 usb-fuzzer: main usb gadget fuzzer driver
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=1327f2ee600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> dashboard link: https://syzkaller.appspot.com/bug?extid=a4b088ebfbadf5f82150
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=128acc6a600000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1082c8e2600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+a4b088ebfbadf5f82150@syzkaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: use-after-free in ld_usb_interrupt_in_callback+0x40c/0x4c0
> drivers/usb/misc/ldusb.c:276
> Write of size 4 at addr ffff8881cdf0b55c by task udevd/238
>
> CPU: 1 PID: 238 Comm: udevd Not tainted 5.3.0-rc2+ #25
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>   <IRQ>
>   __dump_stack lib/dump_stack.c:77 [inline]
>   dump_stack+0xca/0x13e lib/dump_stack.c:113
>   print_address_description+0x6a/0x32c mm/kasan/report.c:351
>   __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
>   kasan_report+0xe/0x12 mm/kasan/common.c:612
>   ld_usb_interrupt_in_callback+0x40c/0x4c0 drivers/usb/misc/ldusb.c:276

#syz dup: KASAN: use-after-free Read in ld_usb_release

>   __usb_hcd_giveback_urb+0x1f2/0x470 drivers/usb/core/hcd.c:1757
>   usb_hcd_giveback_urb+0x368/0x420 drivers/usb/core/hcd.c:1822
>   dummy_timer+0x120f/0x2fa2 drivers/usb/gadget/udc/dummy_hcd.c:1965
>   call_timer_fn+0x179/0x650 kernel/time/timer.c:1322
>   expire_timers kernel/time/timer.c:1366 [inline]
>   __run_timers kernel/time/timer.c:1685 [inline]
>   __run_timers kernel/time/timer.c:1653 [inline]
>   run_timer_softirq+0x5cc/0x14b0 kernel/time/timer.c:1698
>   __do_softirq+0x221/0x912 kernel/softirq.c:292
>   invoke_softirq kernel/softirq.c:373 [inline]
>   irq_exit+0x178/0x1a0 kernel/softirq.c:413
>   exiting_irq arch/x86/include/asm/apic.h:537 [inline]
>   smp_apic_timer_interrupt+0x12f/0x500 arch/x86/kernel/apic/apic.c:1095
>   apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828
>   </IRQ>
> RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
> RIP: 0010:check_kcov_mode kernel/kcov.c:140 [inline]
> RIP: 0010:__sanitizer_cov_trace_pc+0x9/0x50 kernel/kcov.c:174
> Code: 25 8c c4 cf 07 41 bc f4 ff ff ff e8 8a a0 ea ff 48 c7 05 76 c4 cf 07
> 00 00 00 00 e9 ee eb ff ff 90 65 48 8b 04 25 00 ef 01 00 <65> 8b 15 e8 ff
> c3 7e 81 e2 00 01 1f 00 48 8b 34 24 75 2b 8b 90 20
> RSP: 0018:ffff8881d391fd80 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
> RAX: ffff8881d38b9800 RBX: dffffc0000000000 RCX: ffffffff815ab382
> RDX: 00007fefa32f1000 RSI: 00007fefa32f1000 RDI: 0000000000000006
> RBP: ffff8881d3822b20 R08: ffff8881d38b9800 R09: ffffed103a7f68a7
> R10: ffffed103a7f68a6 R11: ffff8881d3fb4533 R12: 00007fefa32f1000
> R13: 00007fefa32f1000 R14: ffff8881d3822b00 R15: ffff8881d3822b20
>   browse_rb mm/mmap.c:346 [inline]
>   validate_mm+0x2f0/0x610 mm/mmap.c:418
>   remove_vma_list mm/mmap.c:2592 [inline]
>   __do_munmap+0x847/0xf90 mm/mmap.c:2833
>   __vm_munmap+0xe6/0x170 mm/mmap.c:2853
>   __do_sys_munmap mm/mmap.c:2878 [inline]
>   __se_sys_munmap mm/mmap.c:2875 [inline]
>   __x64_sys_munmap+0x62/0x80 mm/mmap.c:2875
>   do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
>   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x7fefa33ccd37
> Code: f0 ff ff 73 01 c3 48 8b 0d fe c0 2a 00 31 d2 48 29 c2 64 89 11 48 83
> c8 ff eb ea 90 90 90 90 90 90 90 90 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff
> ff 73 01 c3 48 8b 0d d1 c0 2a 00 31 d2 48 29 c2 64
> RSP: 002b:00007ffc17b3cfe8 EFLAGS: 00000206 ORIG_RAX: 000000000000000b
> RAX: ffffffffffffffda RBX: 0000000000ffdd10 RCX: 00007fefa33ccd37
> RDX: 0000000000000000 RSI: 0000000000001000 RDI: 00007fefa3cc2000
> RBP: 0000000000000000 R08: 00007fefa3cbc7a0 R09: 0000000000000000
> R10: 5f4344555f425355 R11: 0000000000000206 R12: 0000000000000000
> R13: 0000000000ffdd10 R14: 0000000000000006 R15: 0000000000000000
>
> Allocated by task 1757:
>   save_stack+0x1b/0x80 mm/kasan/common.c:69
>   set_track mm/kasan/common.c:77 [inline]
>   __kasan_kmalloc mm/kasan/common.c:487 [inline]
>   __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:460
>   kmalloc include/linux/slab.h:552 [inline]
>   kzalloc include/linux/slab.h:748 [inline]
>   ld_usb_probe+0x6e/0xa65 drivers/usb/misc/ldusb.c:661
>   usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
>   really_probe+0x281/0x650 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:709
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:816
>   bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:882
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2114
>   usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
>   generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
>   usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
>   really_probe+0x281/0x650 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:709
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:816
>   bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:882
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2114
>   usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
>   hub_port_connect drivers/usb/core/hub.c:5098 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
>   port_event drivers/usb/core/hub.c:5359 [inline]
>   hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
>   process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
>   worker_thread+0x96/0xe20 kernel/workqueue.c:2415
>   kthread+0x318/0x420 kernel/kthread.c:255
>   ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
>
> Freed by task 1757:
>   save_stack+0x1b/0x80 mm/kasan/common.c:69
>   set_track mm/kasan/common.c:77 [inline]
>   __kasan_slab_free+0x130/0x180 mm/kasan/common.c:449
>   slab_free_hook mm/slub.c:1423 [inline]
>   slab_free_freelist_hook mm/slub.c:1470 [inline]
>   slab_free mm/slub.c:3012 [inline]
>   kfree+0xe4/0x2f0 mm/slub.c:3953
>   ld_usb_probe+0x728/0xa65 drivers/usb/misc/ldusb.c:744
>   usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
>   really_probe+0x281/0x650 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:709
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:816
>   bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:882
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2114
>   usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
>   generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
>   usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
>   really_probe+0x281/0x650 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:709
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:816
>   bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:882
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2114
>   usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
>   hub_port_connect drivers/usb/core/hub.c:5098 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
>   port_event drivers/usb/core/hub.c:5359 [inline]
>   hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
>   process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
>   worker_thread+0x96/0xe20 kernel/workqueue.c:2415
>   kthread+0x318/0x420 kernel/kthread.c:255
>   ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
>
> The buggy address belongs to the object at ffff8881cdf0b400
>   which belongs to the cache kmalloc-512 of size 512
> The buggy address is located 348 bytes inside of
>   512-byte region [ffff8881cdf0b400, ffff8881cdf0b600)
> The buggy address belongs to the page:
> page:ffffea000737c280 refcount:1 mapcount:0 mapping:ffff8881da002500
> index:0x0 compound_mapcount: 0
> flags: 0x200000000010200(slab|head)
> raw: 0200000000010200 ffffea00072c5400 0000000200000002 ffff8881da002500
> raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>   ffff8881cdf0b400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>   ffff8881cdf0b480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ffff8881cdf0b500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                                      ^
>   ffff8881cdf0b580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>   ffff8881cdf0b600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ---
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>
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