CVE-2026-89450iommu/tegra241-cmdqv: Reject a vSID wider than the SID_MATCH field

Official description

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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/d903d99ffd22b0180bd745a43f221c21bcdd8d7c
• https://git.kernel.org/stable/c/445204550f894ca325ac80a21e3df177ad073798
• https://git.kernel.org/stable/c/4379610c79bd88ddbea10e7f6c21e16d4b338c6b