The ioctl32 v4l1 compat code for VIDIOCSMICROCODE does not check the destination buffer for a copy_from_user() call, which allows anyone with access to a v4l device to write to arbitrary kernel memory locations. This allocates the memory and uses a compat pointer for the copy. Acknowledgements: Red Hat would like to thank Kees Cook for reporting this issue.
Introduced in eb4eeccc (v2.6.18-rc4), also see in 92f45bad (v2.6.29-rc1).
Public demo..: http://www.youtube.com/watch?v=CLxpae-M7Js
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.
Statement: This issue did not affect the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 3 and 4 as they did not include the upstream commit eb4eeccc that introduced the problem. It did not affect Red Hat Enterprise Linux 5 and Red Hat Enterprise MRG as they did not provide support for the Stradis driver that uses the vulnerable compat code for VIDIOCSMICROCODE. As a preventive measure, we have removed the vulnerable code in Red Hat Enterprise Linux 5 via https://rhn.redhat.com/errata/RHSA-2010-0839.html. We plan to remove the vulnerable code in a future kernel update in Red Hat Enterprise MRG.
http://www.outflux.net/blog/archives/2010/10/19/cve-2010-2963-v4l-compat-exploit/
Upstream commit: http://git.kernel.org/linus/3e645d6b485446c54c6745c5e2cf5c528fe4deec
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Via RHSA-2010:0839 https://rhn.redhat.com/errata/RHSA-2010-0839.html
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2010:0842 https://rhn.redhat.com/errata/RHSA-2010-0842.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.