Description: Reference counting error in overlayfs/shiftfs error path when used in conjuction with aufs
References:
 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-15794
 https://usn.ubuntu.com/usn/usn-4208-1
 https://usn.ubuntu.com/usn/usn-4209-1
 https://bugs.launchpad.net/bugs/1850994
Notes:
Bugs:
upstream: N/A "introduced by aufs support patch"
5.10-upstream-stable: N/A "introduced by aufs support patch"
4.19-upstream-stable: N/A "introduced by aufs support patch"
4.9-upstream-stable: N/A "introduced by aufs support patch"
3.16-upstream-stable: N/A "introduced by aufs support patch"
sid: needed
5.10-bullseye-security: needed
4.19-buster-security: needed
4.9-stretch-security: N/A "overlayfs passes through mmap"
3.16-jessie-security: N/A "overlayfs not present"