linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* KASAN: use-after-free Read in usb_kill_urb
@ 2019-08-09 17:48 syzbot
  2019-08-09 18:44 ` Prashant Malani
  2019-08-09 19:26 ` Alan Stern
  0 siblings, 2 replies; 7+ messages in thread
From: syzbot @ 2019-08-09 17:48 UTC (permalink / raw)
  To: andreyknvl, gregkh, gustavo, linux-kernel, linux-usb, syzkaller-bugs

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=1799392c600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
dashboard link: https://syzkaller.appspot.com/bug?extid=22ae4e3b9fcc8a5c153a
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1134c802600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13278c4a600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+22ae4e3b9fcc8a5c153a@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in atomic_read  
include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in usb_kill_urb drivers/usb/core/urb.c:695  
[inline]
BUG: KASAN: use-after-free in usb_kill_urb+0x24b/0x2c0  
drivers/usb/core/urb.c:687
Read of size 4 at addr ffff8881d635b110 by task syz-executor672/1999

CPU: 1 PID: 1999 Comm: syz-executor672 Not tainted 5.3.0-rc2+ #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __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
  check_memory_region_inline mm/kasan/generic.c:185 [inline]
  check_memory_region+0x128/0x190 mm/kasan/generic.c:192
  atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
  usb_kill_urb drivers/usb/core/urb.c:695 [inline]
  usb_kill_urb+0x24b/0x2c0 drivers/usb/core/urb.c:687
  ld_usb_abort_transfers+0xb7/0x1d0 drivers/usb/misc/ldusb.c:196
  ld_usb_release+0x19f/0x400 drivers/usb/misc/ldusb.c:406
  __fput+0x2d7/0x840 fs/file_table.c:280
  task_work_run+0x13f/0x1c0 kernel/task_work.c:113
  exit_task_work include/linux/task_work.h:22 [inline]
  do_exit+0x8ef/0x2c50 kernel/exit.c:878
  do_group_exit+0x125/0x340 kernel/exit.c:982
  __do_sys_exit_group kernel/exit.c:993 [inline]
  __se_sys_exit_group kernel/exit.c:991 [inline]
  __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:991
  do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440418
Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0  
0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff  
ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00
RSP: 002b:00007ffe884abf88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440418
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004bff50 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 22:
  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:557 [inline]
  usb_alloc_urb+0x65/0xb0 drivers/usb/core/urb.c:73
  ld_usb_probe+0x3e1/0xa65 drivers/usb/misc/ldusb.c:708
  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 22:
  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
  urb_destroy drivers/usb/core/urb.c:26 [inline]
  kref_put include/linux/kref.h:65 [inline]
  usb_free_urb.part.0+0x7a/0xc0 drivers/usb/core/urb.c:95
  usb_free_urb+0x1b/0x30 drivers/usb/core/urb.c:94
  ld_usb_delete+0x3f/0x130 drivers/usb/misc/ldusb.c:211
  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 ffff8881d635b100
  which belongs to the cache kmalloc-192 of size 192
The buggy address is located 16 bytes inside of
  192-byte region [ffff8881d635b100, ffff8881d635b1c0)
The buggy address belongs to the page:
page:ffffea000758d6c0 refcount:1 mapcount:0 mapping:ffff8881da002a00  
index:0x0
flags: 0x200000000000200(slab)
raw: 0200000000000200 dead000000000100 dead000000000122 ffff8881da002a00
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8881d635b000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8881d635b080: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
> ffff8881d635b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                          ^
  ffff8881d635b180: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
  ffff8881d635b200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: KASAN: use-after-free Read in usb_kill_urb
  2019-08-09 17:48 KASAN: use-after-free Read in usb_kill_urb syzbot
@ 2019-08-09 18:44 ` Prashant Malani
  2019-08-09 19:00   ` Alan Stern
  2019-08-09 19:26 ` Alan Stern
  1 sibling, 1 reply; 7+ messages in thread
From: Prashant Malani @ 2019-08-09 18:44 UTC (permalink / raw)
  To: syzbot
  Cc: andreyknvl, gregkh, gustavo, linux-kernel, linux-usb, syzkaller-bugs

(Sorry for the resend, I was in HTML mode earlier :S)
Hi,

I'm trying to get up to speed on USB kernel code. Sounds like
dev->intf should have been set to NULL for the error path in
ld_usb_probe() ?

https://elixir.bootlin.com/linux/latest/source/drivers/usb/misc/ldusb.c#L666


On Fri, Aug 9, 2019 at 10:48 AM syzbot
<syzbot+22ae4e3b9fcc8a5c153a@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=1799392c600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> dashboard link: https://syzkaller.appspot.com/bug?extid=22ae4e3b9fcc8a5c153a
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1134c802600000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13278c4a600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+22ae4e3b9fcc8a5c153a@syzkaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: use-after-free in atomic_read
> include/asm-generic/atomic-instrumented.h:26 [inline]
> BUG: KASAN: use-after-free in usb_kill_urb drivers/usb/core/urb.c:695
> [inline]
> BUG: KASAN: use-after-free in usb_kill_urb+0x24b/0x2c0
> drivers/usb/core/urb.c:687
> Read of size 4 at addr ffff8881d635b110 by task syz-executor672/1999
>
> CPU: 1 PID: 1999 Comm: syz-executor672 Not tainted 5.3.0-rc2+ #25
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>   __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
>   check_memory_region_inline mm/kasan/generic.c:185 [inline]
>   check_memory_region+0x128/0x190 mm/kasan/generic.c:192
>   atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
>   usb_kill_urb drivers/usb/core/urb.c:695 [inline]
>   usb_kill_urb+0x24b/0x2c0 drivers/usb/core/urb.c:687
>   ld_usb_abort_transfers+0xb7/0x1d0 drivers/usb/misc/ldusb.c:196
>   ld_usb_release+0x19f/0x400 drivers/usb/misc/ldusb.c:406
>   __fput+0x2d7/0x840 fs/file_table.c:280
>   task_work_run+0x13f/0x1c0 kernel/task_work.c:113
>   exit_task_work include/linux/task_work.h:22 [inline]
>   do_exit+0x8ef/0x2c50 kernel/exit.c:878
>   do_group_exit+0x125/0x340 kernel/exit.c:982
>   __do_sys_exit_group kernel/exit.c:993 [inline]
>   __se_sys_exit_group kernel/exit.c:991 [inline]
>   __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:991
>   do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
>   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x440418
> Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0
> 0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff
> ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00
> RSP: 002b:00007ffe884abf88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440418
> RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
> RBP: 00000000004bff50 R08: 00000000000000e7 R09: ffffffffffffffd0
> R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000001
> R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000
>
> Allocated by task 22:
>   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:557 [inline]
>   usb_alloc_urb+0x65/0xb0 drivers/usb/core/urb.c:73
>   ld_usb_probe+0x3e1/0xa65 drivers/usb/misc/ldusb.c:708
>   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 22:
>   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
>   urb_destroy drivers/usb/core/urb.c:26 [inline]
>   kref_put include/linux/kref.h:65 [inline]
>   usb_free_urb.part.0+0x7a/0xc0 drivers/usb/core/urb.c:95
>   usb_free_urb+0x1b/0x30 drivers/usb/core/urb.c:94
>   ld_usb_delete+0x3f/0x130 drivers/usb/misc/ldusb.c:211
>   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 ffff8881d635b100
>   which belongs to the cache kmalloc-192 of size 192
> The buggy address is located 16 bytes inside of
>   192-byte region [ffff8881d635b100, ffff8881d635b1c0)
> The buggy address belongs to the page:
> page:ffffea000758d6c0 refcount:1 mapcount:0 mapping:ffff8881da002a00
> index:0x0
> flags: 0x200000000000200(slab)
> raw: 0200000000000200 dead000000000100 dead000000000122 ffff8881da002a00
> raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>   ffff8881d635b000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>   ffff8881d635b080: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
> > ffff8881d635b100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                           ^
>   ffff8881d635b180: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>   ffff8881d635b200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this bug, for details see:
> https://goo.gl/tpsmEJ#testing-patches

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: KASAN: use-after-free Read in usb_kill_urb
  2019-08-09 18:44 ` Prashant Malani
@ 2019-08-09 19:00   ` Alan Stern
  0 siblings, 0 replies; 7+ messages in thread
From: Alan Stern @ 2019-08-09 19:00 UTC (permalink / raw)
  To: Prashant Malani
  Cc: syzbot, andreyknvl, gregkh, gustavo, linux-kernel, linux-usb,
	syzkaller-bugs

On Fri, 9 Aug 2019, Prashant Malani wrote:

> Hi,
> 
> I'm trying to get up to speed on USB kernel code. Sounds like
> dev->intf should have been set to NULL for the error path in
> ld_usb_probe() ?

Why should it?

After all, dev gets deallocated at the end of ld_usb_probe(), where 
ld_usb_delete() is called.  Who cares what value is stored in 
deallocated memory?

Alan Stern


^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: KASAN: use-after-free Read in usb_kill_urb
  2019-08-09 17:48 KASAN: use-after-free Read in usb_kill_urb syzbot
  2019-08-09 18:44 ` Prashant Malani
@ 2019-08-09 19:26 ` Alan Stern
  2019-08-09 19:46   ` syzbot
  1 sibling, 1 reply; 7+ messages in thread
From: Alan Stern @ 2019-08-09 19:26 UTC (permalink / raw)
  To: syzbot
  Cc: andreyknvl, gregkh, gustavo, linux-kernel, linux-usb, syzkaller-bugs

On Fri, 9 Aug 2019, syzbot 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=1799392c600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> dashboard link: https://syzkaller.appspot.com/bug?extid=22ae4e3b9fcc8a5c153a
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1134c802600000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13278c4a600000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+22ae4e3b9fcc8a5c153a@syzkaller.appspotmail.com
> 
> ==================================================================
> BUG: KASAN: use-after-free in atomic_read  
> include/asm-generic/atomic-instrumented.h:26 [inline]
> BUG: KASAN: use-after-free in usb_kill_urb drivers/usb/core/urb.c:695  
> [inline]
> BUG: KASAN: use-after-free in usb_kill_urb+0x24b/0x2c0  
> drivers/usb/core/urb.c:687
> Read of size 4 at addr ffff8881d635b110 by task syz-executor672/1999
> 
> CPU: 1 PID: 1999 Comm: syz-executor672 Not tainted 5.3.0-rc2+ #25
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
> Google 01/01/2011
> Call Trace:
>   __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
>   check_memory_region_inline mm/kasan/generic.c:185 [inline]
>   check_memory_region+0x128/0x190 mm/kasan/generic.c:192
>   atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
>   usb_kill_urb drivers/usb/core/urb.c:695 [inline]
>   usb_kill_urb+0x24b/0x2c0 drivers/usb/core/urb.c:687
>   ld_usb_abort_transfers+0xb7/0x1d0 drivers/usb/misc/ldusb.c:196
>   ld_usb_release+0x19f/0x400 drivers/usb/misc/ldusb.c:406

Since this also involves ldusb.c, maybe it will be fixed by the same 
patch as the other bug.

Alan Stern


#syz test: https://github.com/google/kasan.git e96407b4

Index: usb-devel/drivers/usb/core/file.c
===================================================================
--- usb-devel.orig/drivers/usb/core/file.c
+++ usb-devel/drivers/usb/core/file.c
@@ -193,9 +193,10 @@ int usb_register_dev(struct usb_interfac
 		intf->minor = minor;
 		break;
 	}
-	up_write(&minor_rwsem);
-	if (intf->minor < 0)
+	if (intf->minor < 0) {
+		up_write(&minor_rwsem);
 		return -EXFULL;
+	}
 
 	/* create a usb class device for this usb interface */
 	snprintf(name, sizeof(name), class_driver->name, minor - minor_base);
@@ -203,12 +204,11 @@ int usb_register_dev(struct usb_interfac
 				      MKDEV(USB_MAJOR, minor), class_driver,
 				      "%s", kbasename(name));
 	if (IS_ERR(intf->usb_dev)) {
-		down_write(&minor_rwsem);
 		usb_minors[minor] = NULL;
 		intf->minor = -1;
-		up_write(&minor_rwsem);
 		retval = PTR_ERR(intf->usb_dev);
 	}
+	up_write(&minor_rwsem);
 	return retval;
 }
 EXPORT_SYMBOL_GPL(usb_register_dev);
@@ -234,12 +234,12 @@ void usb_deregister_dev(struct usb_inter
 		return;
 
 	dev_dbg(&intf->dev, "removing %d minor\n", intf->minor);
+	device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
 
 	down_write(&minor_rwsem);
 	usb_minors[intf->minor] = NULL;
 	up_write(&minor_rwsem);
 
-	device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
 	intf->usb_dev = NULL;
 	intf->minor = -1;
 	destroy_usb_class();


^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: KASAN: use-after-free Read in usb_kill_urb
  2019-08-09 19:26 ` Alan Stern
@ 2019-08-09 19:46   ` syzbot
  2019-08-09 20:52     ` Alan Stern
  0 siblings, 1 reply; 7+ messages in thread
From: syzbot @ 2019-08-09 19:46 UTC (permalink / raw)
  To: andreyknvl, gregkh, gustavo, linux-kernel, linux-usb, stern,
	syzkaller-bugs

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger  
crash:

Reported-and-tested-by:  
syzbot+22ae4e3b9fcc8a5c153a@syzkaller.appspotmail.com

Tested on:

commit:         e96407b4 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git
kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
patch:          https://syzkaller.appspot.com/x/patch.diff?x=173f2d2c600000

Note: testing is done by a robot and is best-effort only.

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: KASAN: use-after-free Read in usb_kill_urb
  2019-08-09 19:46   ` syzbot
@ 2019-08-09 20:52     ` Alan Stern
  2019-08-12 12:03       ` Andrey Konovalov
  0 siblings, 1 reply; 7+ messages in thread
From: Alan Stern @ 2019-08-09 20:52 UTC (permalink / raw)
  To: syzbot
  Cc: andreyknvl, gregkh, gustavo, linux-kernel, linux-usb, syzkaller-bugs

On Fri, 9 Aug 2019, syzbot wrote:

> Hello,
> 
> syzbot has tested the proposed patch and the reproducer did not trigger  
> crash:
> 
> Reported-and-tested-by:  
> syzbot+22ae4e3b9fcc8a5c153a@syzkaller.appspotmail.com
> 
> Tested on:
> 
> commit:         e96407b4 usb-fuzzer: main usb gadget fuzzer driver
> git tree:       https://github.com/google/kasan.git
> kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=173f2d2c600000
> 
> Note: testing is done by a robot and is best-effort only.

This shows that this bug is a duplicate of extid=30cf45ebfe0b0c4847a1.  
This fact is also visible in the console logs; both have lines saying 
something like:

[  549.416341][   T22] sysfs: cannot create duplicate filename '/class/usbmisc/ldusb0'

and

[  549.958755][   T22] ldusb 1-1:0.28: Not able to get a minor for this device.

preceding the invalid access.

Alan Stern


^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: KASAN: use-after-free Read in usb_kill_urb
  2019-08-09 20:52     ` Alan Stern
@ 2019-08-12 12:03       ` Andrey Konovalov
  0 siblings, 0 replies; 7+ messages in thread
From: Andrey Konovalov @ 2019-08-12 12:03 UTC (permalink / raw)
  To: Alan Stern
  Cc: syzbot, Greg Kroah-Hartman, Gustavo A. R. Silva, LKML, USB list,
	syzkaller-bugs

On Fri, Aug 9, 2019 at 10:52 PM Alan Stern <stern@rowland.harvard.edu> wrote:
>
> On Fri, 9 Aug 2019, syzbot wrote:
>
> > Hello,
> >
> > syzbot has tested the proposed patch and the reproducer did not trigger
> > crash:
> >
> > Reported-and-tested-by:
> > syzbot+22ae4e3b9fcc8a5c153a@syzkaller.appspotmail.com
> >
> > Tested on:
> >
> > commit:         e96407b4 usb-fuzzer: main usb gadget fuzzer driver
> > git tree:       https://github.com/google/kasan.git
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=cfa2c18fb6a8068e
> > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > patch:          https://syzkaller.appspot.com/x/patch.diff?x=173f2d2c600000
> >
> > Note: testing is done by a robot and is best-effort only.
>
> This shows that this bug is a duplicate of extid=30cf45ebfe0b0c4847a1.

Let's mark it as one:

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

I'll also mark all bugs that involve ldusb as duplicates, as they all
likely are.

> This fact is also visible in the console logs; both have lines saying
> something like:
>
> [  549.416341][   T22] sysfs: cannot create duplicate filename '/class/usbmisc/ldusb0'
>
> and
>
> [  549.958755][   T22] ldusb 1-1:0.28: Not able to get a minor for this device.
>
> preceding the invalid access.
>
> Alan Stern
>

^ permalink raw reply	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2019-08-12 12:04 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-09 17:48 KASAN: use-after-free Read in usb_kill_urb syzbot
2019-08-09 18:44 ` Prashant Malani
2019-08-09 19:00   ` Alan Stern
2019-08-09 19:26 ` Alan Stern
2019-08-09 19:46   ` syzbot
2019-08-09 20:52     ` Alan Stern
2019-08-12 12:03       ` Andrey Konovalov

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).