High · published September 12, 2026
In the Linux kernel, the following vulnerability has been resolved:
iommu/tegra241-cmdqv: Reject a vSID wider than the SID_MATCH field
tegra241_vintf_init_vsid() programs the guest-provided vSID into SID_MATCH,
whose VIRT_SID field spans bits [20:1] with bit 0 as the match-enable flag.
The HW therefore matches only a 20-bit Stream ID.
The bound check rejects only virt_sid > UINT_MAX, which admits a value far
wider than the field. The write "virt_sid << 1 | 0x1" then drops every bit
above 20: a virt_sid of 0x80000000 lands as SID_MATCH = 0x1, a valid match
on vSID 0, so the entry aliases the wrong Stream ID. Because vdev->virt_id
is guest-controlled, a VMM can trigger it.
Validate virt_sid against the field width with FIELD_MAX(), and program the
register with FIELD_PREP() so the value and the field stay consistent.