Linux-USB Archive on lore.kernel.org
 help / color / Atom feed
* KMSAN: uninit-value in smsc75xx_bind
@ 2019-08-09  8:48 syzbot
  2019-08-13 12:43 ` Oliver Neukum
  0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2019-08-09  8:48 UTC (permalink / raw)
  To: davem, glider, linux-kernel, linux-usb, netdev,
	steve.glendinning, syzkaller-bugs

Hello,

syzbot found the following crash on:

HEAD commit:    beaab8a3 fix KASAN build
git tree:       kmsan
console output: https://syzkaller.appspot.com/x/log.txt?x=13d7b65c600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4db781fe35a84ef5
dashboard link: https://syzkaller.appspot.com/bug?extid=6966546b78d050bb0b5d
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14ab9ef0600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11be2b34600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6966546b78d050bb0b5d@syzkaller.appspotmail.com

==================================================================
BUG: KMSAN: uninit-value in smsc75xx_wait_ready  
drivers/net/usb/smsc75xx.c:976 [inline]
BUG: KMSAN: uninit-value in smsc75xx_bind+0x541/0x12d0  
drivers/net/usb/smsc75xx.c:1483
CPU: 0 PID: 2892 Comm: kworker/0:2 Not tainted 5.2.0+ #15
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+0x191/0x1f0 lib/dump_stack.c:113
  kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109
  __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
  smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:976 [inline]
  smsc75xx_bind+0x541/0x12d0 drivers/net/usb/smsc75xx.c:1483
  usbnet_probe+0x10d3/0x3950 drivers/net/usb/usbnet.c:1722
  usb_probe_interface+0xd19/0x1310 drivers/usb/core/driver.c:361
  really_probe+0x1344/0x1d90 drivers/base/dd.c:513
  driver_probe_device+0x1ba/0x510 drivers/base/dd.c:670
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:777
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x489/0x750 drivers/base/dd.c:843
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:890
  bus_probe_device+0x131/0x390 drivers/base/bus.c:514
  device_add+0x25b5/0x2df0 drivers/base/core.c:2111
  usb_set_configuration+0x309f/0x3710 drivers/usb/core/message.c:2027
  generic_probe+0xe7/0x280 drivers/usb/core/generic.c:210
  usb_probe_device+0x146/0x200 drivers/usb/core/driver.c:266
  really_probe+0x1344/0x1d90 drivers/base/dd.c:513
  driver_probe_device+0x1ba/0x510 drivers/base/dd.c:670
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:777
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x489/0x750 drivers/base/dd.c:843
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:890
  bus_probe_device+0x131/0x390 drivers/base/bus.c:514
  device_add+0x25b5/0x2df0 drivers/base/core.c:2111
  usb_new_device+0x23e5/0x2fb0 drivers/usb/core/hub.c:2534
  hub_port_connect drivers/usb/core/hub.c:5089 [inline]
  hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
  port_event drivers/usb/core/hub.c:5350 [inline]
  hub_event+0x5853/0x7320 drivers/usb/core/hub.c:5432
  process_one_work+0x1572/0x1f00 kernel/workqueue.c:2269
  process_scheduled_works kernel/workqueue.c:2331 [inline]
  worker_thread+0x189c/0x2460 kernel/workqueue.c:2417
  kthread+0x4b5/0x4f0 kernel/kthread.c:256
  ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355

Local variable description: ----buf.i93@smsc75xx_bind
Variable was created at:
  __smsc75xx_read_reg drivers/net/usb/smsc75xx.c:83 [inline]
  smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:969 [inline]
  smsc75xx_bind+0x44c/0x12d0 drivers/net/usb/smsc75xx.c:1483
  usbnet_probe+0x10d3/0x3950 drivers/net/usb/usbnet.c:1722
==================================================================


---
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] 4+ messages in thread

* Re: KMSAN: uninit-value in smsc75xx_bind
  2019-08-09  8:48 KMSAN: uninit-value in smsc75xx_bind syzbot
@ 2019-08-13 12:43 ` Oliver Neukum
  2019-08-13 15:08   ` Andrey Konovalov
  0 siblings, 1 reply; 4+ messages in thread
From: Oliver Neukum @ 2019-08-13 12:43 UTC (permalink / raw)
  To: syzbot, davem, glider, syzkaller-bugs, steve.glendinning,
	linux-kernel, linux-usb, netdev

Am Freitag, den 09.08.2019, 01:48 -0700 schrieb syzbot:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    beaab8a3 fix KASAN build
> git tree:       kmsan

[..]
> Call Trace:
>   __dump_stack lib/dump_stack.c:77 [inline]
>   dump_stack+0x191/0x1f0 lib/dump_stack.c:113
>   kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109
>   __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
>   smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:976 [inline]
>   smsc75xx_bind+0x541/0x12d0 drivers/net/usb/smsc75xx.c:1483

> 
> Local variable description: ----buf.i93@smsc75xx_bind
> Variable was created at:
>   __smsc75xx_read_reg drivers/net/usb/smsc75xx.c:83 [inline]
>   smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:969 [inline]
>   smsc75xx_bind+0x44c/0x12d0 drivers/net/usb/smsc75xx.c:1483
>   usbnet_probe+0x10d3/0x3950 drivers/net/usb/usbnet.c:1722

Hi,

this looks like a false positive to me.
The offending code is likely this:

        if (size) {
                buf = kmalloc(size, GFP_KERNEL);
                if (!buf)
                        goto out;
        }

        err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
                              cmd, reqtype, value, index, buf, size,
                              USB_CTRL_GET_TIMEOUT);

which uses 'buf' uninitialized. But it is used for input.
What is happening here?

	Regards
		Oliver




^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: KMSAN: uninit-value in smsc75xx_bind
  2019-08-13 12:43 ` Oliver Neukum
@ 2019-08-13 15:08   ` Andrey Konovalov
  2019-08-14 10:16     ` Oliver Neukum
  0 siblings, 1 reply; 4+ messages in thread
From: Andrey Konovalov @ 2019-08-13 15:08 UTC (permalink / raw)
  To: Oliver Neukum
  Cc: syzbot, David S. Miller, Alexander Potapenko, syzkaller-bugs,
	steve.glendinning, LKML, USB list, netdev

On Tue, Aug 13, 2019 at 2:43 PM Oliver Neukum <oneukum@suse.com> wrote:
>
> Am Freitag, den 09.08.2019, 01:48 -0700 schrieb syzbot:
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit:    beaab8a3 fix KASAN build
> > git tree:       kmsan
>
> [..]
> > Call Trace:
> >   __dump_stack lib/dump_stack.c:77 [inline]
> >   dump_stack+0x191/0x1f0 lib/dump_stack.c:113
> >   kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109
> >   __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
> >   smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:976 [inline]
> >   smsc75xx_bind+0x541/0x12d0 drivers/net/usb/smsc75xx.c:1483
>
> >
> > Local variable description: ----buf.i93@smsc75xx_bind
> > Variable was created at:
> >   __smsc75xx_read_reg drivers/net/usb/smsc75xx.c:83 [inline]
> >   smsc75xx_wait_ready drivers/net/usb/smsc75xx.c:969 [inline]
> >   smsc75xx_bind+0x44c/0x12d0 drivers/net/usb/smsc75xx.c:1483
> >   usbnet_probe+0x10d3/0x3950 drivers/net/usb/usbnet.c:1722
>
> Hi,
>
> this looks like a false positive to me.
> The offending code is likely this:
>
>         if (size) {
>                 buf = kmalloc(size, GFP_KERNEL);
>                 if (!buf)
>                         goto out;
>         }
>
>         err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
>                               cmd, reqtype, value, index, buf, size,
>                               USB_CTRL_GET_TIMEOUT);
>
> which uses 'buf' uninitialized. But it is used for input.
> What is happening here?

AFAICS, the uninitialized use of buf that KMSAN points out is in the
"if (buf & PMT_CTL_DEV_RDY)"  statement in smsc75xx_wait_ready(). Does
__smsc75xx_read_reg/usb_control_msg() always initialize buf? Can it
just initialize the first few bytes for example?

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: KMSAN: uninit-value in smsc75xx_bind
  2019-08-13 15:08   ` Andrey Konovalov
@ 2019-08-14 10:16     ` Oliver Neukum
  0 siblings, 0 replies; 4+ messages in thread
From: Oliver Neukum @ 2019-08-14 10:16 UTC (permalink / raw)
  To: Andrey Konovalov
  Cc: David S. Miller, Alexander Potapenko, syzkaller-bugs,
	steve.glendinning, syzbot, LKML, USB list, netdev

Am Dienstag, den 13.08.2019, 17:08 +0200 schrieb Andrey Konovalov:
> On Tue, Aug 13, 2019 at 2:43 PM Oliver Neukum <oneukum@suse.com> wrote:
> > 
> > 
> > Hi,
> > 
> > this looks like a false positive to me.
> > The offending code is likely this:
> > 
> >         if (size) {
> >                 buf = kmalloc(size, GFP_KERNEL);
> >                 if (!buf)
> >                         goto out;
> >         }
> > 
> >         err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
> >                               cmd, reqtype, value, index, buf, size,
> >                               USB_CTRL_GET_TIMEOUT);
> > 
> > which uses 'buf' uninitialized. But it is used for input.
> > What is happening here?
> 
> AFAICS, the uninitialized use of buf that KMSAN points out is in the
> "if (buf & PMT_CTL_DEV_RDY)"  statement in smsc75xx_wait_ready(). Does
> __smsc75xx_read_reg/usb_control_msg() always initialize buf? Can it
> just initialize the first few bytes for example?
> 

Hi,

you are unfortunately right and this is not the only driver vulnerable
in this way. I am going through them.

	Regards
		Oliver


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, back to index

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-09  8:48 KMSAN: uninit-value in smsc75xx_bind syzbot
2019-08-13 12:43 ` Oliver Neukum
2019-08-13 15:08   ` Andrey Konovalov
2019-08-14 10:16     ` Oliver Neukum

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

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-usb linux-usb/ https://lore.kernel.org/linux-usb \
		linux-usb@vger.kernel.org linux-usb@archiver.kernel.org
	public-inbox-index linux-usb


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-usb


AGPL code for this site: git clone https://public-inbox.org/ public-inbox