"TITLE":"Reference counting error in overlayfs/shiftfs error path when used in conjuction with aufs"
},
"affects":{
"vendor":{
"vendor_data":[
{
"product":{
"product_data":[
{
"product_name":"Linux kernel",
"version":{
"version_data":[
{
"version_affected":"<",
"version_name":"5.3 kernel",
"version_value":"5.3.0-24.26"
},
{
"version_affected":"<",
"version_name":"5.0 kernel",
"version_value":"5.0.0-37.40"
}
]
}
}
]
},
"vendor_name":"Ubuntu"
}
]
}
},
"credit":[
{
"lang":"eng",
"value":"Jann Horn of Google Project Zero"
}
],
"data_format":"MITRE",
"data_type":"CVE",
"data_version":"4.0",
"description":{
"description_data":[
{
"lang":"eng",
"value":"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."
