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

Overview

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

• Linux >= 4dc0d12474f9d4833c3dd96b73d61e406d3f5dc7 < d903d99ffd22b0180bd745a43f221c21bcdd8d7c
• Linux >= 4dc0d12474f9d4833c3dd96b73d61e406d3f5dc7 < 445204550f894ca325ac80a21e3df177ad073798
• Linux >= 4dc0d12474f9d4833c3dd96b73d61e406d3f5dc7 < 4379610c79bd88ddbea10e7f6c21e16d4b338c6b
• Linux 6.17

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

Vendor advisories

• Red Hat VEX · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-09-27 · vex