Skip to content
CVE PROGRAM SOURCE RECORD7.1 High

CVE-2019-15794

Reference counting error in overlayfs/shiftfs error path when used in conjuction with aufs

Read JSON ↗CVE.org ↗
Status
Published
Published
Updated
Assigning organization
canonical

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Ubuntu Linux kernel

  • 5.3 kernel to < 5.3.0-24.26affected
  • 5.0 kernel to < 5.0.0-37.40affected

References