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.
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History
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MITRE
Status: PUBLISHED
Assigner: canonical
Published: 2020-04-23T23:55:25.039982Z
Updated: 2024-09-16T19:52:18.313Z
Reserved: 2019-08-29T00:00:00
Link: CVE-2019-15794
Vulnrichment
No data.
NVD
Status : Modified
Published: 2020-04-24T00:15:11.933
Modified: 2024-11-21T04:29:28.880
Link: CVE-2019-15794
Redhat