| Name | CVE-2019-15794 |
| Description | Overlayfs in the Linux kernel and shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, both replace vma->vm_file in their mmap handlers. On error the original value is not restored, and the reference is put for the file to which vm_file points. On upstream kernels this is not an issue, as no callers dereference vm_file following after call_mmap() returns an error. However, the aufs patchs change mmap_region() to replace the fput() using a local variable with vma_fput(), which will fput() vm_file, leading to a refcount underflow. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| linux (PTS) | jessie, jessie (lts) | 3.16.84-1 | fixed |
| stretch (security) | 4.9.320-2 | fixed | |
| stretch (lts), stretch | 4.9.320-3 | fixed | |
| buster (security), buster, buster (lts) | 4.19.316-1 | vulnerable | |
| bullseye | 5.10.223-1 | vulnerable | |
| bullseye (security) | 5.10.226-1 | vulnerable | |
| bookworm | 6.1.106-3 | fixed | |
| bookworm (security) | 6.1.112-1 | fixed | |
| sid, trixie | 6.11.5-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| linux | source | wheezy | (unfixed) | end-of-life | ||
| linux | source | jessie | (not affected) | |||
| linux | source | stretch | (not affected) | |||
| linux | source | buster | (unfixed) | end-of-life | ||
| linux | source | (unstable) | 5.16.7-1 |
[stretch] - linux <not-affected> (overlayfs passes through mmap)
[jessie] - linux <not-affected> (overlayfs not present)
https://bugs.launchpad.net/bugs/1850994