Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()
netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it is wanting to unlock and compares that to rreq->no_unlock_folio so that it doesn’t unlock a folio being read for netfs_perform_write() or netfs_write_begin().
However, given that netfs_unlock_abandoned_read_pages() is called after NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it’s not allowed to dereference is the one specified by ->no_unlock_folio as ownership immediately reverts to the caller.
Fix this by storing the folio pointer instead and using that rather than the index. Also fix netfs_unlock_read_folio() where the same applies.
Details
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 13 | Planned | — |