Re: [CHECKER] 8 potential user-pointer errors that allow arbitrary writes to kernel

From: Junfeng Yang (yjf@stanford.edu)
Date: Mon Apr 28 2003 - 14:11:37 EST


Thanks a lot for the confirmations!

-Junfeng

On 28 Apr 2003, Alan Cox wrote:

> On Llu, 2003-04-28 at 07:50, Junfeng Yang wrote:
> > /home/junfeng/linux-tainted/drivers/usb/media/vicam.c:617:vicam_ioctl:
> > ERROR:TAINTED:617:617: dereferencing tainted ptr 'vp' [Callstack:
> > /home/junfeng/linux-tainted/drivers/scsi/sg.c:1002:vicam_ioctl((tainted
> > 3))]
> >
> > struct video_picture *vp = (struct video_picture
> > *) arg;
> >
> > DBG("VIDIOCSPICT depth = %d, pal = %d\n",
> > vp->depth,
> > vp->palette);
> >
> >
> > Error --->
>
> Correct report. Fixed in 2.4.21-ac now
>
> > /home/junfeng/linux-tainted/drivers/video/sis/sis_main.c:2476:sisfb_ioctl:
> > ERROR:TAINTED:2476:2476: dereferencing tainted ptr 'x' [Callstack:
> > /home/junfeng/linux-tainted/drivers/video/sstfb.c:808:sisfb_ioctl((tainted
> > 3))]
> >
>
> Correct - already fixed in 2.4.21-ac
>
> > ---------------------------------------------------------
> > [BUG] can write to anywhere in kernel. do_read is assigned to
> > file_operations.read, which can take tainted inputs. even the parm itself
> > has a name pUserBuffer
> >
> > /home/junfeng/linux-tainted/drivers/isdn/eicon/linchr.c:166:do_read:
> > ERROR:TAINTED:166:166: passing tainted ptr 'pClientLogBuffer' to
> > __constant_memcpy [Callstack:
> > /home/junfeng/linux-tainted/drivers/scsi/sg.c:362:do_read((tainted 1))]
> >
> >
> > pHeadItem = (klog_t *) DivasLogFifoRead();
> >
> Correct - fixed in 2.4.21-ac now
>
> > [BUG] can write to anywhere in kernel. in the same subdir,
> > midi_synth.c:midi_synth_ioctl does __copy_to_user(not copy_to_user?). it
> > could be that there are some assumptions about the devices.
> >
> > /home/junfeng/linux-tainted/sound/oss/mpu401.c:792:mpu_synth_ioctl:
> > ERROR:TAINTED:792:792: passing tainted ptr 'arg' to __constant_memcpy
> > [Callstack:
> > /home/junfeng/linux-tainted/sound/oss/midi_synth.c:270:mpu_synth_ioctl((tainted
> > 2))]
>
> The verify is done in soundcard.c
> Fixed mpu_synth_ioctl in 2.4.21-ac
>
> > [BUG] can write to anywhere in kernel. mdc800_device_read is assigned to
> > file_operations.read, which can take tainted inputs
> >
> > /home/junfeng/linux-tainted/drivers/usb/image/mdc800.c:750:mdc800_device_read:
> > ERROR:TAINTED:750:750: passing tainted ptr 'ptr' to __memcpy [Callstack:
> > /home/junfeng/linux-tainted/drivers/scsi/sg.c:362:mdc800_device_read((tainted
> > 1))]
>
> Correct. Fixed in 2.4.21-ac
>
>
> > [BUG] can write to anywhere in kernel. file_operations.write
> >
> > /home/junfeng/linux-tainted/drivers/usb/image/mdc800.c:805:mdc800_device_write:
> > ERROR:TAINTED:805:805: dereferencing tainted ptr 'buf + i' [Callstack:
> > /home/junfeng/linux-tainted/drivers/media/dvb/av7110/av7110.c:3858:mdc800_device_write((tainted
> > 1))]
>
> Correct, fixed in 2.4.21-ac
>
>
> > [BUG] can write to anywhere in kernel. awe_ioctl is assigned to
> > file_operations.ioctl
> >
> > /home/junfeng/linux-tainted/sound/oss/awe_wave.c:2049:awe_ioctl:
> > ERROR:TAINTED:2049:2049: passing tainted ptr 'arg' to __constant_memcpy
> > [Callstack:
> > /home/junfeng/linux-tainted/sound/oss/midi_synth.c:270:awe_ioctl((tainted
> > 2))]
> >
> > case SNDCTL_SYNTH_INFO:
> > if (playing_mode == AWE_PLAY_DIRECT)
> > awe_info.nr_voices = awe_max_voices;
> > else
> > awe_info.nr_voices = AWE_MAX_CHANNELS;
> >
> > Error --->
> > memcpy((char*)arg, &awe_info, sizeof(awe_info));
>
> Already fixed in 2.4, but correct report
>

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