diff options
| author | Michael Bommarito <michael.bommarito@gmail.com> | 2026-05-19 09:25:19 -0400 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2026-05-20 08:08:11 +0100 |
| commit | 9ce754ed8e7ab4e3999767ce1505f85c449ccb07 (patch) | |
| tree | e9cce53630fc63508aa3c5a4620b615171fb880b | |
| parent | effc0a39b8e0f30670fe24f51e44329d4324e566 (diff) | |
KVM: arm64: vgic-its: Reject restored DTE with out-of-range num_eventid_bits
Userspace can restore an ITS Device Table Entry whose Size field encodes
more EventID bits than the virtual ITS supports. The live MAPD path
rejects that state, but vgic_its_restore_dte() accepts it and stores the
out-of-range value in dev->num_eventid_bits.
Reject restored DTEs with num_eventid_bits > VITS_TYPER_IDBITS before
allocating the device. This mirrors the MAPD check and prevents the
restored state from reaching vgic_its_restore_itt(), where the unchecked
value can be converted into an oversized scan_its_table() range.
Fixes: 57a9a117154c ("KVM: arm64: vgic-its: Device table save/restore")
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Link: https://lore.kernel.org/r/20260519132519.2142458-1-michael.bommarito@gmail.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
| -rw-r--r-- | arch/arm64/kvm/vgic/vgic-its.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c index 2ea9f1c7ebcd..1d7e5d560af4 100644 --- a/arch/arm64/kvm/vgic/vgic-its.c +++ b/arch/arm64/kvm/vgic/vgic-its.c @@ -2307,6 +2307,10 @@ static int vgic_its_restore_dte(struct vgic_its *its, u32 id, /* dte entry is valid */ offset = (entry & KVM_ITS_DTE_NEXT_MASK) >> KVM_ITS_DTE_NEXT_SHIFT; + /* Mimic the MAPD behaviour and reject invalid EID bits. */ + if (num_eventid_bits > VITS_TYPER_IDBITS) + return -EINVAL; + if (!vgic_its_check_id(its, baser, id, NULL)) return -EINVAL; |