[PATCH 0/1][T/X/B/C/D] CVE-2018-18710 - Information leak in cdrom driver

[Tyler Hicks]

https://people.canonical.com/~ubuntu-security/cve/2018/CVE-2018-18710.html

 An issue was discovered in the Linux kernel through 4.19. An information
 leak in cdrom_ioctl_select_disc in drivers/cdrom/cdrom.c could be used by
 local attackers to read kernel memory because a cast from unsigned long to
 int interferes with bounds checking. This is similar to CVE-2018-10940 and
 CVE-2018-16658.

Clean cherry pick all the way back to Trusty. I was unable to test this
specific line of code in the cdrom ioctl handler because I think it requires a
cdrom with multiple disc slots. However, the build logs are clean and the fix
is easy to review.

Tyler