KVM: arm64: vgic-v3: take an LPI reference in vgic_v3_save_pending_tables
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.12.114, 6.18.51, 7.2.5
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: vgic-v3: take an LPI reference in vgic_v3_save_pending_tables vgic_v3_save_pending_tables() iterates dist->lpi_xa using xa_for_each() and dereferences the returned struct vgic_irq in the loop body without holding a reference on the LPI. The xarray iterator only provides temporary RCU coverage while looking up the current entry. That is not sufficient for this loop body, which reads fields from struct vgic_irq and performs guest memory accesses before the iteration completes. A concurrent path can trigger this race: the irqfd cached injection path (vgic_its_inject_cached_translation) obtains a transient LPI reference via vgic_its_check_cache() without holding kvm->lock, vcpu->mutex, config_lock, or its_lock. If guest ITS DISCARD then drops the cache and ITE references under its_lock, the transient inject reference may become the final one. When vgic_put_irq() drops it, the LPI is erased from lpi_xa and freed via kfree_rcu(). Meanwhile, vgic_v3_save_pending_tables() may still hold a stale pointer obtained from the xarray iterator and dereference it after the RCU grace period completes. Fix this by re-fetching each iterated LPI via vgic_get_irq(), which takes a stable reference, and dropping it with vgic_put_irq() on all paths. This matches the pattern already used by other lpi_xa iterators in the vgic ITS code.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 280771252c1bae0947215c59fb9ea6a8d9f8399d · fixed in 4000462866bc71f16d1bfb3cf8e969f95150cd64; From 280771252c1bae0947215c59fb9ea6a8d9f8399d · fixed in 7631f95297560157d3a9283cb999e3be00103348; From 280771252c1bae0947215c59fb9ea6a8d9f8399d · fixed in d3a2d20b7248ea67465af1cf79c79f90ff70926c; From 280771252c1bae0947215c59fb9ea6a8d9f8399d · fixed in f5b8f203bfc07a5a257dff859e66d2c500f9f509
- Linux Linux
4.12
- KernelLinux
From 4.12.0 · fixed in 6.12.114; From 6.13.0 · fixed in 6.18.51; From 6.19.0 · fixed in 7.2.5