[PATCH v3 0/3] KVM: guest_memfd: Fix signed offset+size goof
From: Sean Christopherson
Date: Wed May 27 2026 - 22:11:27 EST
Fix a bug where KVM fails to reject a comically large offset into guest_memfd
if offset+size results in a signed, negative value. Add a testcase to prove
the bug, and to serve as a regression test.
Note, v1 and v2 was part of larger series.
v3:
- Use uoff_t, not u64. [the combined might of Sean and Ackerley]
- Explaining exactly what is broken. [Ackerley]
- Add a regression test.
v2: https://lore.kernel.org/all/20260522-fix-sev-gmem-post-populate-v2-0-3f196bfad5a1@xxxxxxxxxx
v1: https://lore.kernel.org/r/20260522-fix-sev-gmem-post-populate-v1-0-9fc8d6437b65@xxxxxxxxxx
Sean Christopherson (3):
KVM: guest_memfd: Treat memslot binding offset+size as unsigned values
KVM: selftests: Expand the guest_memfd test macros to allow passing
the VM
KVM: selftests: Add guest_memfd regression test signed offset+size bug
.../testing/selftests/kvm/guest_memfd_test.c | 24 +++++++++++++++++--
virt/kvm/guest_memfd.c | 8 +++----
virt/kvm/kvm_mm.h | 7 ++++--
3 files changed, 31 insertions(+), 8 deletions(-)
base-commit: 9f2a49c511cb05b85745e1578e4fd425bff87f58
--
2.54.0.794.g4f17f83d09-goog