From: Michael Bommarito <michael.bommarito@gmail.com> stable inclusion from stable-v6.6.142 commit dab9f93251b2c86a033de6098d0c73afddd55d4a category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/16271 CVE: CVE-2026-64106 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 9ce754ed8e7ab4e3999767ce1505f85c449ccb07 upstream. 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.c... Signed-off-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: arch/arm64/kvm/vgic/vgic-its.c [ context conflict. ] Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> --- arch/arm64/kvm/vgic/vgic-its.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c index 86e3914e3148..acf611bc6f7e 100644 --- a/arch/arm64/kvm/vgic/vgic-its.c +++ b/arch/arm64/kvm/vgic/vgic-its.c @@ -2424,6 +2424,10 @@ 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; + dev = vgic_its_alloc_device(its, id, itt_addr, num_eventid_bits); if (IS_ERR(dev)) return PTR_ERR(dev); -- 2.34.1