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* divide error in usbtmc_generic_read
@ 2019-08-14 11:38 syzbot
  2019-08-14 13:25 ` Oliver Neukum
  2019-08-15 14:28 ` Oliver Neukum
  0 siblings, 2 replies; 7+ messages in thread
From: syzbot @ 2019-08-14 11:38 UTC (permalink / raw)
  To: andreyknvl, gregkh, guido.kiener, linux-kernel, linux-usb,
	steve_bayless, syzkaller-bugs

Hello,

syzbot found the following crash on:

HEAD commit:    d0847550 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=16295d4a600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dbc9c80cc095da19
dashboard link: https://syzkaller.appspot.com/bug?extid=55b0304b360654a7537b
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1288a31c600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15282e86600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+55b0304b360654a7537b@syzkaller.appspotmail.com

divide error: 0000 [#1] SMP KASAN
CPU: 1 PID: 1761 Comm: syz-executor063 Not tainted 5.3.0-rc4+ #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:usbtmc_generic_read+0x135/0x1190 drivers/usb/class/usbtmc.c:816
Code: 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2  
0f 85 50 08 00 00 41 0f b7 6e 34 31 d2 31 ff 8b 44 24 28 <f7> f5 89 d6 41  
89 d4 e8 2f 54 c9 fd 44 8b 6c 24 28 45 85 e4 44 89
RSP: 0018:ffff8881d2b77a58 EFLAGS: 00010246
RAX: 0000000000000002 RBX: 000000004f894bad RCX: ffffffff837487cd
RDX: 0000000000000000 RSI: ffffffff837487da RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff8881d20a0000 R09: ffffed103a56ef90
R10: ffffed103a56ef8f R11: 0000000000000003 R12: ffff8881d08e7180
R13: 0000000020000000 R14: ffff8881d0404c80 R15: ffff8881d08e7180
FS:  0000555555b74880(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006cc090 CR3: 00000001d615e000 CR4: 00000000001406e0
Call Trace:
  usbtmc_ioctl_generic_read drivers/usb/class/usbtmc.c:1029 [inline]
  usbtmc_ioctl+0x27d/0x2ab0 drivers/usb/class/usbtmc.c:2089
  vfs_ioctl fs/ioctl.c:46 [inline]
  file_ioctl fs/ioctl.c:509 [inline]
  do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696
  ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
  __do_sys_ioctl fs/ioctl.c:720 [inline]
  __se_sys_ioctl fs/ioctl.c:718 [inline]
  __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
  do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4419a9
Code: e8 8c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 cb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd0abd6738 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004419a9
RDX: 0000000020000000 RSI: 00000000c0145b0e RDI: 0000000000000004
RBP: 000000000000a984 R08: 000000000000000f R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402700
R13: 0000000000402790 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace a91d281a4d83213c ]---
RIP: 0010:usbtmc_generic_read+0x135/0x1190 drivers/usb/class/usbtmc.c:816
Code: 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2  
0f 85 50 08 00 00 41 0f b7 6e 34 31 d2 31 ff 8b 44 24 28 <f7> f5 89 d6 41  
89 d4 e8 2f 54 c9 fd 44 8b 6c 24 28 45 85 e4 44 89
RSP: 0018:ffff8881d2b77a58 EFLAGS: 00010246
RAX: 0000000000000002 RBX: 000000004f894bad RCX: ffffffff837487cd
RDX: 0000000000000000 RSI: ffffffff837487da RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff8881d20a0000 R09: ffffed103a56ef90
R10: ffffed103a56ef8f R11: 0000000000000003 R12: ffff8881d08e7180
R13: 0000000020000000 R14: ffff8881d0404c80 R15: ffff8881d08e7180
FS:  0000555555b74880(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006cc090 CR3: 00000001d615e000 CR4: 00000000001406e0


---
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: divide error in usbtmc_generic_read
  2019-08-14 11:38 divide error in usbtmc_generic_read syzbot
@ 2019-08-14 13:25 ` Oliver Neukum
  2019-08-14 13:38   ` syzbot
  2019-08-15 14:28 ` Oliver Neukum
  1 sibling, 1 reply; 7+ messages in thread
From: Oliver Neukum @ 2019-08-14 13:25 UTC (permalink / raw)
  To: syzbot, andreyknvl, syzkaller-bugs, steve_bayless, gregkh,
	guido.kiener, linux-usb

Am Mittwoch, den 14.08.2019, 04:38 -0700 schrieb syzbot:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    d0847550 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=16295d4a600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=dbc9c80cc095da19
> dashboard link: https://syzkaller.appspot.com/bug?extid=55b0304b360654a7537b
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1288a31c600000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15282e86600000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+55b0304b360654a7537b@syzkaller.appspotmail.com


#syz test: https://github.com/google/kasan.git d0847550

From 5fa900e86e57d92a0b23a1a60ff4f4f13e997a93 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@suse.com>
Date: Wed, 14 Aug 2019 15:21:41 +0200
Subject: [PATCH] usbtmc: more sanity checking for packet size

A malicious device can make the driver divide ny zero
with a nonsense maximum packet size.

SIgned-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/class/usbtmc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 4942122b2346..11042ca56818 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -2364,6 +2364,8 @@ static int usbtmc_probe(struct usb_interface *intf,
 
 	data->bulk_in = bulk_in->bEndpointAddress;
 	data->wMaxPacketSize = usb_endpoint_maxp(bulk_in);
+	if (!data->wMaxPacketSize)
+		goto err_put;
 	dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n", data->bulk_in);
 
 	data->bulk_out = bulk_out->bEndpointAddress;
-- 
2.16.4


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: divide error in usbtmc_generic_read
  2019-08-14 13:25 ` Oliver Neukum
@ 2019-08-14 13:38   ` syzbot
  2019-08-14 13:52     ` Andrey Konovalov
  2019-08-15 13:31     ` Oliver Neukum
  0 siblings, 2 replies; 7+ messages in thread
From: syzbot @ 2019-08-14 13:38 UTC (permalink / raw)
  To: andreyknvl, gregkh, guido.kiener, linux-usb, oneukum,
	steve_bayless, syzkaller-bugs

Hello,

syzbot has tested the proposed patch but the reproducer still triggered  
crash:
KASAN: use-after-free Read in usbtmc_disconnect

usb 5-1: USB disconnect, device number 2
==================================================================
BUG: KASAN: use-after-free in __mutex_lock_common  
kernel/locking/mutex.c:912 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0xf23/0x1360  
kernel/locking/mutex.c:1077
Read of size 8 at addr ffff8881d63299c8 by task kworker/1:0/17

CPU: 1 PID: 17 Comm: kworker/1:0 Not tainted 5.3.0-rc4+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
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
  __mutex_lock_common kernel/locking/mutex.c:912 [inline]
  __mutex_lock+0xf23/0x1360 kernel/locking/mutex.c:1077
  usbtmc_disconnect+0x58/0x180 drivers/usb/class/usbtmc.c:2443
  usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
  __device_release_driver drivers/base/dd.c:1134 [inline]
  device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
  bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
  device_del+0x420/0xb10 drivers/base/core.c:2339
  usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
  usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
  hub_port_connect drivers/usb/core/hub.c:4949 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
  port_event drivers/usb/core/hub.c:5359 [inline]
  hub_event+0x1454/0x3640 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

Allocated by task 1737:
  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]
  usbtmc_probe+0xad/0x1360 drivers/usb/class/usbtmc.c:2328
  usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
  really_probe+0x281/0x6d0 drivers/base/dd.c:548
  driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
  bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
  __device_attach+0x217/0x360 drivers/base/dd.c:894
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
  device_add+0xae6/0x16f0 drivers/base/core.c:2165
  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+0x281/0x6d0 drivers/base/dd.c:548
  driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
  bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
  __device_attach+0x217/0x360 drivers/base/dd.c:894
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
  device_add+0xae6/0x16f0 drivers/base/core.c:2165
  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 1737:
  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:1474 [inline]
  slab_free mm/slub.c:3016 [inline]
  kfree+0xe4/0x2f0 mm/slub.c:3957
  kref_put include/linux/kref.h:65 [inline]
  usbtmc_probe+0x55c/0x1360 drivers/usb/class/usbtmc.c:2433
  usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
  really_probe+0x281/0x6d0 drivers/base/dd.c:548
  driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
  bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
  __device_attach+0x217/0x360 drivers/base/dd.c:894
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
  device_add+0xae6/0x16f0 drivers/base/core.c:2165
  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+0x281/0x6d0 drivers/base/dd.c:548
  driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
  __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
  bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
  __device_attach+0x217/0x360 drivers/base/dd.c:894
  bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
  device_add+0xae6/0x16f0 drivers/base/core.c:2165
  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 ffff8881d6329900
  which belongs to the cache kmalloc-512 of size 512
The buggy address is located 200 bytes inside of
  512-byte region [ffff8881d6329900, ffff8881d6329b00)
The buggy address belongs to the page:
page:ffffea000758ca00 refcount:1 mapcount:0 mapping:ffff8881da002500  
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 ffffea0007585680 0000000700000007 ffff8881da002500
raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff8881d6329880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffff8881d6329900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8881d6329980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                               ^
  ffff8881d6329a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff8881d6329a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit:         d0847550 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10ac29ee600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dbc9c80cc095da19
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11f3b2e2600000


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: divide error in usbtmc_generic_read
  2019-08-14 13:38   ` syzbot
@ 2019-08-14 13:52     ` Andrey Konovalov
  2019-08-15 13:31     ` Oliver Neukum
  1 sibling, 0 replies; 7+ messages in thread
From: Andrey Konovalov @ 2019-08-14 13:52 UTC (permalink / raw)
  To: syzbot
  Cc: Greg Kroah-Hartman, guido.kiener, USB list, Oliver Neukum,
	steve_bayless, syzkaller-bugs

On Wed, Aug 14, 2019 at 3:38 PM syzbot
<syzbot+55b0304b360654a7537b@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot has tested the proposed patch but the reproducer still triggered
> crash:
> KASAN: use-after-free Read in usbtmc_disconnect

Looks like a different bug in the same driver that gets triggered by
the same reproducer =)

You fix looks good to me.

>
> usb 5-1: USB disconnect, device number 2
> ==================================================================
> BUG: KASAN: use-after-free in __mutex_lock_common
> kernel/locking/mutex.c:912 [inline]
> BUG: KASAN: use-after-free in __mutex_lock+0xf23/0x1360
> kernel/locking/mutex.c:1077
> Read of size 8 at addr ffff8881d63299c8 by task kworker/1:0/17
>
> CPU: 1 PID: 17 Comm: kworker/1:0 Not tainted 5.3.0-rc4+ #1
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Workqueue: usb_hub_wq hub_event
> 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
>   __mutex_lock_common kernel/locking/mutex.c:912 [inline]
>   __mutex_lock+0xf23/0x1360 kernel/locking/mutex.c:1077
>   usbtmc_disconnect+0x58/0x180 drivers/usb/class/usbtmc.c:2443
>   usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
>   __device_release_driver drivers/base/dd.c:1134 [inline]
>   device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
>   bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
>   device_del+0x420/0xb10 drivers/base/core.c:2339
>   usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
>   usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2199
>   hub_port_connect drivers/usb/core/hub.c:4949 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
>   port_event drivers/usb/core/hub.c:5359 [inline]
>   hub_event+0x1454/0x3640 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
>
> Allocated by task 1737:
>   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]
>   usbtmc_probe+0xad/0x1360 drivers/usb/class/usbtmc.c:2328
>   usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
>   really_probe+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   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+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   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 1737:
>   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:1474 [inline]
>   slab_free mm/slub.c:3016 [inline]
>   kfree+0xe4/0x2f0 mm/slub.c:3957
>   kref_put include/linux/kref.h:65 [inline]
>   usbtmc_probe+0x55c/0x1360 drivers/usb/class/usbtmc.c:2433
>   usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
>   really_probe+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   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+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   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 ffff8881d6329900
>   which belongs to the cache kmalloc-512 of size 512
> The buggy address is located 200 bytes inside of
>   512-byte region [ffff8881d6329900, ffff8881d6329b00)
> The buggy address belongs to the page:
> page:ffffea000758ca00 refcount:1 mapcount:0 mapping:ffff8881da002500
> index:0x0 compound_mapcount: 0
> flags: 0x200000000010200(slab|head)
> raw: 0200000000010200 ffffea0007585680 0000000700000007 ffff8881da002500
> raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>   ffff8881d6329880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>   ffff8881d6329900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ffff8881d6329980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                                ^
>   ffff8881d6329a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>   ffff8881d6329a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================
>
>
> Tested on:
>
> commit:         d0847550 usb-fuzzer: main usb gadget fuzzer driver
> git tree:       https://github.com/google/kasan.git
> console output: https://syzkaller.appspot.com/x/log.txt?x=10ac29ee600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=dbc9c80cc095da19
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=11f3b2e2600000
>

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: divide error in usbtmc_generic_read
  2019-08-14 13:38   ` syzbot
  2019-08-14 13:52     ` Andrey Konovalov
@ 2019-08-15 13:31     ` Oliver Neukum
  1 sibling, 0 replies; 7+ messages in thread
From: Oliver Neukum @ 2019-08-15 13:31 UTC (permalink / raw)
  To: syzbot, andreyknvl, syzkaller-bugs, steve_bayless, gregkh,
	guido.kiener, linux-usb

Am Mittwoch, den 14.08.2019, 06:38 -0700 schrieb syzbot:
> syzbot has tested the proposed patch but the reproducer still triggered  
> crash:
> KASAN: use-after-free Read in usbtmc_disconnect

I am afraid that is a difficiency in KASAN that should be fixed.
Is the class of the error compared if I leave in more of the
original bug report? Actually the ID is still there, so it really
should return an inconclusive in these cases.

	Regards
		Oliver


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: divide error in usbtmc_generic_read
  2019-08-14 11:38 divide error in usbtmc_generic_read syzbot
  2019-08-14 13:25 ` Oliver Neukum
@ 2019-08-15 14:28 ` Oliver Neukum
  2019-08-15 14:48   ` syzbot
  1 sibling, 1 reply; 7+ messages in thread
From: Oliver Neukum @ 2019-08-15 14:28 UTC (permalink / raw)
  To: syzbot, andreyknvl, syzkaller-bugs, steve_bayless, gregkh,
	guido.kiener, linux-usb

Am Mittwoch, den 14.08.2019, 04:38 -0700 schrieb syzbot:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    d0847550 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=16295d4a600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=dbc9c80cc095da19
> dashboard link: https://syzkaller.appspot.com/bug?extid=55b0304b360654a7537b
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1288a31c600000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15282e86600000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+55b0304b360654a7537b@syzkaller.appspotmail.com

#syz test: https://github.com/google/kasan.git d0847550

From df64f5cd2e6a9b43c75bb7e3276b8805a225db75 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@suse.com>
Date: Wed, 14 Aug 2019 15:21:41 +0200
Subject: [PATCH] usbtmc: more sanity checking for packet size

A malicious device can make the driver divide ny zero
with a nonsense maximum packet size.

V2: return a sensible error code

SIgned-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/class/usbtmc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 4942122b2346..36858ddd8d9b 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -2362,8 +2362,11 @@ static int usbtmc_probe(struct usb_interface *intf,
 		goto err_put;
 	}
 
+	retcode = -EINVAL;
 	data->bulk_in = bulk_in->bEndpointAddress;
 	data->wMaxPacketSize = usb_endpoint_maxp(bulk_in);
+	if (!data->wMaxPacketSize)
+		goto err_put;
 	dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n", data->bulk_in);
 
 	data->bulk_out = bulk_out->bEndpointAddress;
-- 
2.16.4


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: divide error in usbtmc_generic_read
  2019-08-15 14:28 ` Oliver Neukum
@ 2019-08-15 14:48   ` syzbot
  0 siblings, 0 replies; 7+ messages in thread
From: syzbot @ 2019-08-15 14:48 UTC (permalink / raw)
  To: andreyknvl, gregkh, guido.kiener, linux-usb, oneukum,
	steve_bayless, syzkaller-bugs

Hello,

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

Reported-and-tested-by:  
syzbot+55b0304b360654a7537b@syzkaller.appspotmail.com

Tested on:

commit:         d0847550 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git
kernel config:  https://syzkaller.appspot.com/x/.config?x=dbc9c80cc095da19
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15e22d02600000

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

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, back to index

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-14 11:38 divide error in usbtmc_generic_read syzbot
2019-08-14 13:25 ` Oliver Neukum
2019-08-14 13:38   ` syzbot
2019-08-14 13:52     ` Andrey Konovalov
2019-08-15 13:31     ` Oliver Neukum
2019-08-15 14:28 ` Oliver Neukum
2019-08-15 14:48   ` syzbot

Linux-USB Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-usb/0 linux-usb/git/0.git

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	# initialize and index your mirror using the following commands:
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	public-inbox-index linux-usb


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