A flaw was found in the Linux kernels implementation of overlayfs. An attacker can leak a file resources in the system by opening a large file with write permissions on a overlay filesystem that is insufficient to deal with the size of the write.
When unmounting the underlying device, the system is unable to free an inode and this will consume resources. Repeating this for all available inodes and memory will create a denial of service situation.
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1370467]
This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6 as the code with the flaw is not present in the products listed.
This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 7 and MRG-2. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
Name: CAI Qian (Red Hat Engineering)