Ok, only Stradis driver actually uses it. I doubt that stradis still work
nowadays, and it is not compiled on RHEL5/RHEL6. Need to check mrg. Patch is as
simple as remove the compat bits for this ioctl.

(In reply to comment #1)
> Ok, only Stradis driver actually uses it. I doubt that stradis still work
> nowadays, and it is not compiled on RHEL5/RHEL6.

Well in that case we may close this as notabug, right Eugene?

(In reply to comment #2)
> (In reply to comment #1)
> > Ok, only Stradis driver actually uses it. I doubt that stradis still work
> > nowadays, and it is not compiled on RHEL5/RHEL6.
> 
> Well in that case we may close this as notabug, right Eugene?

No, we can't. The v4l2-compat layer is called for all V4L2 drivers. The other drivers will return an error code for a VIDIOCSMICROCODE call, but, as the bug is at compat layer, it will affect any system with a V4L hardware.

The effects are limited to machines with some V4L hardware (like a webcam or a TV capture board), so, it affects more workstations and notebooks with RHEL.

rhel5/drivers/media/video/compat_ioctl32.c
static inline int microcode32(struct video_code *kp, struct video_code32 __user *up)
{
        if(!access_ok(VERIFY_READ, up, sizeof(struct video_code32)) ||
                copy_from_user(kp->loadwhat, up->loadwhat, sizeof (up->loadwhat)) ||
                get_user(kp->datasize, &up->datasize) ||
                copy_from_user(kp->data, up->data, up->datasize))
                        return -EFAULT;
        return 0;
}

$ grep compat_ioctl32 Makefile 
obj-$(CONFIG_VIDEO_DEV) += videodev.o v4l2-common.o compat_ioctl32.o

#ifdef CONFIG_VIDEO_V4L1_COMPAT
        case VIDIOCSMICROCODE:
                err = microcode32(&karg.vc, up);
                compatible_arg = 0;
                break;
#endif  

CONFIG_VIDEO_V4L1_COMPAT=y

Even if no drivers uses it, we should just disable it.

in kernel 2.6.18-194.21.1.el5

linux-2.6-v4l-remove-compat-code-for-vidiocsmicrocode.patch

See https://bugzilla.redhat.com/show_bug.cgi?id=642465#c8. Thanks.

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2010-0839.html

    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
A vulnerability was discovered in the 32-bit compatibility code for the VIDIOCSMICROCODE IOCTL (Input/Output Control) in the Video4Linux implementation. It does not affect Red Hat Enterprise Linux 5, but as a preventive measure, this update removes the code. Red Hat would like to thank Kees Cook for reporting this vulnerability.