Re: [ 105/124] af_unix: dont send SCM_CREDENTIAL when dest socket is NULL

From: Stefan Lippers-Hollmann
Date: Wed Apr 03 2013 - 15:11:41 EST


Hi

On Wednesday 03 April 2013, Greg Kroah-Hartman wrote:
> On Wed, Apr 03, 2013 at 05:10:40PM +0200, Sven Joachim wrote:
> > On 2013-04-03 16:00 +0200, Eric Dumazet wrote:
> > > On Wed, 2013-04-03 at 13:41 +0200, Sven Joachim wrote:
> > >> On 2013-04-03 00:11 +0200, Greg Kroah-Hartman wrote:
> > >> > 3.8-stable review patch. If anyone has any objections, please let me know.
> > >>
> > >> I'm seeing several complaints from udevd at boot in both 3.8.6-rc1 and
> > >> 3.9-rc5: "udevd[56]: sender uid=65534, message ignored". Reverting the
> > >> patch below on top of 3.8.6-rc1 fixes that. I'm using udev version 175
> > >> here, and 65534 is the uid of user "nobody".
[â]

I can reproduce this issue on several systems with a Debian unstable
(udev 175, same version as in the upcoming Debian 7.0 'wheezy')
userland. Reverting only this patch from 3.8.6-rc1 avoids the problem.

> > > It might be a wrong sender (application bug or bad identity), and udevd
> > > correctly discards the incoming message.
> >
> > How would I find out the culprit?
>
> Try running 'udevadm monitor' as root and see if something shows up
> there.

There are no re-occuring messages on an idle system, connecting a USB
stick (not mounting) results in these messages.

broken (3.8.6-rc1, with "af_unix: dont send SCM_CREDENTIAL when dest
socket is NULL" applied):

KERNEL[11739.713368] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1 (usb)
KERNEL[11739.713514] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0 (usb)
UDEV [11739.713663] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1 (usb)
KERNEL[11739.713677] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7 (scsi)
KERNEL[11739.713688] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/scsi_host/host7 (scsi_host)
UDEV [11739.713734] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0 (usb)
UDEV [11739.713797] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7 (scsi)
UDEV [11739.713893] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/scsi_host/host7 (scsi_host)
UDEV [11739.718583] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1 (usb)
UDEV [11739.720709] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0 (usb)
UDEV [11739.720900] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7 (scsi)
UDEV [11739.721191] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/scsi_host/host7 (scsi_host)
KERNEL[11740.747996] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0 (scsi)
KERNEL[11740.748032] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0 (scsi)
KERNEL[11740.748042] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/scsi_disk/7:0:0:0 (scsi_disk)
KERNEL[11740.748048] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/scsi_device/7:0:0:0 (scsi_device)
KERNEL[11740.748103] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/scsi_generic/sg5 (scsi_generic)
UDEV [11740.748129] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0 (scsi)
KERNEL[11740.748146] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/bsg/7:0:0:0 (bsg)
UDEV [11740.748251] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0 (scsi)
UDEV [11740.748349] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0 (scsi)
UDEV [11740.748459] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/scsi_disk/7:0:0:0 (scsi_disk)
UDEV [11740.748533] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/scsi_device/7:0:0:0 (scsi_device)
UDEV [11740.748910] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/scsi_generic/sg5 (scsi_generic)
UDEV [11740.749039] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/bsg/7:0:0:0 (bsg)
UDEV [11740.750204] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0 (scsi)
UDEV [11740.750531] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/scsi_disk/7:0:0:0 (scsi_disk)
UDEV [11740.750652] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/scsi_device/7:0:0:0 (scsi_device)
UDEV [11740.751143] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/bsg/7:0:0:0 (bsg)
UDEV [11740.751323] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/scsi_generic/sg5 (scsi_generic)
KERNEL[11740.943534] add /devices/virtual/bdi/8:80 (bdi)
UDEV [11740.943700] add /devices/virtual/bdi/8:80 (bdi)
UDEV [11740.943807] add /devices/virtual/bdi/8:80 (bdi)
KERNEL[11740.987877] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/block/sdf (block)
KERNEL[11740.987921] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/block/sdf/sdf1 (block)
UDEV [11740.988152] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/block/sdf (block)
UDEV [11740.988307] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/block/sdf/sdf1 (block)
UDEV [11741.047184] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/block/sdf (block)
UDEV [11741.104796] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host7/target7:0:0/7:0:0:0/block/sdf/sdf1 (block)

working (3.8.6-rc1, with "af_unix: dont send SCM_CREDENTIAL when dest
socket is NULL" reverted):

KERNEL[637.018561] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1 (usb)
KERNEL[637.018607] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0 (usb)
UDEV [637.023544] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1 (usb)
KERNEL[637.028060] add /module/usb_storage (module)
UDEV [637.028268] add /module/usb_storage (module)
KERNEL[637.028293] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6 (scsi)
KERNEL[637.028332] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/scsi_host/host6 (scsi_host)
KERNEL[637.028364] add /bus/usb/drivers/usb-storage (drivers)
UDEV [637.028586] add /bus/usb/drivers/usb-storage (drivers)
UDEV [637.028614] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0 (usb)
UDEV [637.028910] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6 (scsi)
UDEV [637.029294] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/scsi_host/host6 (scsi_host)
KERNEL[638.062158] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0 (scsi)
KERNEL[638.062191] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0 (scsi)
KERNEL[638.062238] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/scsi_disk/6:0:0:0 (scsi_disk)
KERNEL[638.062280] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/scsi_device/6:0:0:0 (scsi_device)
KERNEL[638.062347] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/scsi_generic/sg5 (scsi_generic)
KERNEL[638.062410] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/bsg/6:0:0:0 (bsg)
UDEV [638.062455] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0 (scsi)
UDEV [638.064574] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0 (scsi)
UDEV [638.064941] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/scsi_disk/6:0:0:0 (scsi_disk)
UDEV [638.064974] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/scsi_device/6:0:0:0 (scsi_device)
UDEV [638.065568] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/bsg/6:0:0:0 (bsg)
UDEV [638.065766] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/scsi_generic/sg5 (scsi_generic)
KERNEL[638.257660] add /devices/virtual/bdi/8:80 (bdi)
UDEV [638.258029] add /devices/virtual/bdi/8:80 (bdi)
KERNEL[638.301820] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/block/sdf (block)
KERNEL[638.301864] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/block/sdf/sdf1 (block)
UDEV [638.361377] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/block/sdf (block)
UDEV [638.420664] add /devices/pci0000:00/0000:00:1a.0/usb7/7-1/7-1.1/7-1.1:1.0/host6/target6:0:0/6:0:0:0/block/sdf/sdf1 (block)


> I can't reproduce this here, running a newer version of udev (195),
> sorry, I don't have any systems with older udev releases.
>
> Note, someone else posted this same error earlier today on the linux-usb
> mailing list, saying that USB storage devices would not automount
> anymore. Does that work properly for you?

Yes, this patch breaks automounting or USB devices under KDE 4.8.4.

Regards
Stefan Lippers-Hollmann
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