Description
fs/overlayfs/copy_up.c in the Linux kernel before 4.2.6 uses an incorrect cleanup code path, which allows local users to cause a denial of service (dentry reference leak) via filesystem operations on a large file in a lower overlayfs layer.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 4.2.6-1 | — |
| Debian 13 | linux | 4.2.6-1 | — |
| Debian 12 | linux | 4.2.6-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | linux-lts-vivid | 3.19.0-41.46~14.04.2 | — |
| Ubuntu 14.04 LTS | linux-lts-wily | 4.2.0-19.23~14.04.1 | — |
References
- [oss-security] 20160823 cve request: overlayfs: Fix dentry reference leak mailing-list
- https://bugzilla.redhat.com/show_bug.cgi?id=1367814
- http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.2.6
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ab79efab0a0ba01a74df782eb7fa44b044dae8b5
- https://github.com/torvalds/linux/commit/ab79efab0a0ba01a74df782eb7fa44b044dae8b5
- 92611 vdb-entry