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feat(rebinding): update MIGTD_DATA to GHCI 1.5 TDINFO format #778

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Merged
jyao1 merged 1 commit into from
Apr 8, 2026
Merged

feat(rebinding): update MIGTD_DATA to GHCI 1.5 TDINFO format #778

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106 changes: 56 additions & 50 deletions src/migtd/src/migration/rebinding.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,6 @@ use crate::migration::servtd_ext::read_servtd_ext;
#[cfg(feature = "spdm_attestation")]
use crate::spdm;
use crate::{event_log, migration::transport::*};
use crypto::hash::digest_sha384;

use crate::{
config,
Expand Down Expand Up @@ -47,9 +46,7 @@ const TDCS_FIELD_WRITE_MASK: u64 = u64::MAX;
const TLS_TIMEOUT: Duration = Duration::from_secs(60); // 60 seconds
// FIXME: Need VMM provide socket information
const MIGTD_DATA_SIGNATURE: &[u8] = b"MIGTDATA";
const MIGTD_DATA_TYPE_INIT_MIG_POLICY: u32 = 0;
const MIGTD_DATA_TYPE_INIT_TD_REPORT: u32 = 1;
const MIGTD_DATA_TYPE_INIT_EVENT_LOG: u32 = 2;
const MIGTD_DATA_TYPE_TDINFO: u32 = 0;

#[repr(C)]
pub struct RebindingToken {
Expand Down Expand Up @@ -126,12 +123,31 @@ impl RebindingInfo {
}

pub struct InitData {
pub init_report: Vec<u8>,
pub init_policy: Vec<u8>,
pub init_event_log: Vec<u8>,
/// The TDINFO_STRUCT of the initial MigTD (per GHCI 1.5, MIGTD_DATA type 0).
pub init_tdinfo: Vec<u8>,
}

impl InitData {
/// TDINFO_STRUCT field offsets and sizes (per TDX Module ABI).
const TDINFO_MROWNER_OFFSET: usize = 112; // attributes(8) + xfam(8) + mrtd(48) + mrconfig_id(48)
const TDINFO_MROWNERCONFIG_OFFSET: usize = 160; // MROWNER_OFFSET + 48
const TDINFO_FIELD_SIZE: usize = SHA384_DIGEST_SIZE;
const TDINFO_MIN_SIZE: usize = 512;

/// Extract mrowner from the TDINFO_STRUCT.
/// Per GHCI 1.5: VMM puts migpolicy.policy_key in tdinfo.mrowner.
pub fn mrowner(&self) -> &[u8] {
&self.init_tdinfo
[Self::TDINFO_MROWNER_OFFSET..Self::TDINFO_MROWNER_OFFSET + Self::TDINFO_FIELD_SIZE]
}

/// Extract mrownerconfig from the TDINFO_STRUCT.
/// Per GHCI 1.5: VMM puts migpolicy.policy_svn in tdinfo.mrownerconfig.
pub fn mrownerconfig(&self) -> &[u8] {
&self.init_tdinfo[Self::TDINFO_MROWNERCONFIG_OFFSET
..Self::TDINFO_MROWNERCONFIG_OFFSET + Self::TDINFO_FIELD_SIZE]
}

pub fn read_from_bytes(b: &[u8]) -> Option<Self> {
if b.len() < 20 || &b[..8] != MIGTD_DATA_SIGNATURE {
return None;
Expand All @@ -141,34 +157,22 @@ impl InitData {
let length = u32::from_le_bytes(b[12..16].try_into().unwrap());
let num_entries = u32::from_le_bytes(b[16..20].try_into().unwrap());

if version != 0x00010000 || b.len() < length as usize {
// Per GHCI 1.5: version must be 0x00010000, numberOfEntry must be 1 (tdinfo)
if version != 0x00010000 || b.len() < length as usize || num_entries != 1 {
return None;
}

let entry = MigtdDataEntry::read_from_bytes(&b[20..])?;
if entry.r#type != MIGTD_DATA_TYPE_TDINFO {
return None;
}

let mut offset = 20;
let mut init_report = None;
let mut init_policy = None;
let mut init_event_log = None;
for _ in 0..num_entries {
let entry = MigtdDataEntry::read_from_bytes(&b[offset..])?;
match entry.r#type {
MIGTD_DATA_TYPE_INIT_MIG_POLICY => init_policy = Some(entry.value),
MIGTD_DATA_TYPE_INIT_TD_REPORT => {
if entry.value.len() > 1024 {
return None;
}
init_report = Some(entry.value.to_vec())
}
MIGTD_DATA_TYPE_INIT_EVENT_LOG => init_event_log = Some(entry.value),
_ => return None,
}
offset += entry.length as usize + 8;
if entry.value.len() < Self::TDINFO_MIN_SIZE {
return None;
}

Some(Self {
init_report: init_report?,
init_policy: init_policy?.to_vec(),
init_event_log: init_event_log?.to_vec(),
init_tdinfo: entry.value.to_vec(),
})
}

Expand All @@ -180,18 +184,12 @@ impl InitData {
// Placeholder for length.
buf.extend_from_slice(&0u32.to_le_bytes());

buf.extend_from_slice(&3u32.to_le_bytes()); // num_entries

// Helper to write entries
let mut write_entry = |type_: u32, value: &[u8]| {
buf.extend_from_slice(&type_.to_le_bytes());
buf.extend_from_slice(&(value.len() as u32).to_le_bytes());
buf.extend_from_slice(value);
};
// Per GHCI 1.5: numberOfEntry = 1, entry type 0 = tdinfo
buf.extend_from_slice(&1u32.to_le_bytes()); // num_entries

write_entry(MIGTD_DATA_TYPE_INIT_MIG_POLICY, &self.init_policy);
write_entry(MIGTD_DATA_TYPE_INIT_TD_REPORT, &self.init_report);
write_entry(MIGTD_DATA_TYPE_INIT_EVENT_LOG, &self.init_event_log);
buf.extend_from_slice(&MIGTD_DATA_TYPE_TDINFO.to_le_bytes());
buf.extend_from_slice(&(self.init_tdinfo.len() as u32).to_le_bytes());
buf.extend_from_slice(&self.init_tdinfo);

let total_size = (buf.len() - start_len) as u32;

Expand All @@ -201,13 +199,9 @@ impl InitData {
}

pub fn get_from_local(report_data: &[u8; 64]) -> Option<Self> {
let report = tdx_tdcall::tdreport::tdcall_report(report_data).ok()?;
Some(Self {
init_report: tdx_tdcall::tdreport::tdcall_report(report_data)
.ok()?
.as_bytes()
.to_vec(),
init_policy: config::get_policy()?.to_vec(),
init_event_log: event_log::get_event_log()?.to_vec(),
init_tdinfo: report.td_info.as_bytes().to_vec(),
})
}
}
Expand Down Expand Up @@ -395,7 +389,7 @@ pub async fn start_rebinding(
.ok_or(MigrationResult::InvalidParameter)?;
let remote_policy = Box::pin(with_timeout(
PRE_SESSION_TIMEOUT,
rebinding_old_pre_session_data_exchange(&mut transport, &init_migtd_data.init_policy),
rebinding_old_pre_session_data_exchange(&mut transport, &init_migtd_data.init_tdinfo),
))
.await
.map_err(|e| {
Expand Down Expand Up @@ -574,15 +568,27 @@ async fn rebinding_old_prepare(
remote_policy: Vec<u8>,
) -> Result<(), MigrationResult> {
let servtd_ext = read_servtd_ext(info.binding_handle, &info.target_td_uuid)?;
let init_policy_hash = digest_sha384(&init_migtd_data.init_policy)?;

// Per GHCI 1.5: init policy key hash is in tdinfo.mrowner.
// Use mrowner directly as the init_policy_hash equivalent.
let init_policy_hash = init_migtd_data.mrowner().to_vec();

// Per GHCI 1.5: init_tdinfo replaces the old init_report (full TDREPORT).
// The TDINFO_STRUCT contains all the measurement fields needed for verification.
let init_tdinfo = &init_migtd_data.init_tdinfo;

// Per GHCI 1.5: init_event_log is no longer part of MIGTD_DATA.
// Use local event log; RATLS cert still carries init_event_log extension
// for responder-side verification of init RTMRs.
let init_event_log = event_log::get_event_log().unwrap_or(&[]);

// TLS client
let mut ratls_client = ratls::client_rebinding(
transport,
remote_policy,
&init_policy_hash,
&init_migtd_data.init_report,
&init_migtd_data.init_event_log,
init_tdinfo,
init_event_log,
&servtd_ext,
)
.map_err(|_| {
Expand Down
20 changes: 12 additions & 8 deletions src/migtd/src/spdm/spdm_req.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -959,21 +959,25 @@ pub async fn send_and_receive_sdm_rebind_attest_info(
.extend_from_slice(servtd_ext.as_bytes())
.ok_or(SPDM_STATUS_BUFFER_FULL)?;

//TD report init
let tdreport_init = &init_migtd_data.init_report;
//TD info init (per GHCI 1.5: MIGTD_DATA type 0 = TDINFO_STRUCT)
// NOTE: VdmMessageElementType::TdReportInit name retained for wire compatibility;
// payload is now TDINFO_STRUCT, not full TDREPORT.
let tdinfo_init = &init_migtd_data.init_tdinfo;
let tdreport_init_element = VdmMessageElement {
element_type: VdmMessageElementType::TdReportInit,
length: tdreport_init.len() as u32,
length: tdinfo_init.len() as u32,
};
cnt += tdreport_init_element
.encode(&mut writer)
.map_err(|_| SPDM_STATUS_BUFFER_FULL)?;
cnt += writer
.extend_from_slice(tdreport_init)
.extend_from_slice(tdinfo_init)
.ok_or(SPDM_STATUS_BUFFER_FULL)?;

//event log init
let event_log_init = &init_migtd_data.init_event_log;
// Per GHCI 1.5: init_event_log is no longer in MIGTD_DATA; use local event log.
// NOTE: EventLogInit VDM element retained for wire compatibility with responder.
let event_log_init = crate::event_log::get_event_log().unwrap_or(&[]);
let event_log_init_element = VdmMessageElement {
element_type: VdmMessageElementType::EventLogInit,
length: event_log_init.len() as u32,
Expand All @@ -986,9 +990,9 @@ pub async fn send_and_receive_sdm_rebind_attest_info(
.ok_or(SPDM_STATUS_BUFFER_FULL)?;

//mig policy init hash
let mig_policy_init = &init_migtd_data.init_policy;
let mig_policy_init_hash =
digest_sha384(mig_policy_init).map_err(|_| SPDM_STATUS_CRYPTO_ERROR)?;
// Per GHCI 1.5: policy_key is in tdinfo.mrowner; sent as init_policy_hash.
// NOTE: MigPolicyInit VDM element name retained for wire compatibility.
let mig_policy_init_hash = init_migtd_data.mrowner().to_vec();
let mig_policy_init_element = VdmMessageElement {
element_type: VdmMessageElementType::MigPolicyInit,
length: mig_policy_init_hash.len() as u32,
Expand Down
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