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Move min-SVN calculation from FMC to ROM. (#1812)
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This change moves the min-SVN check from FMC to ROM.
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@bluegate010
bluegate010 authored Nov 25, 2024
1 parent 0076a1b commit f22cbca
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Showing 6 changed files with 8 additions and 94 deletions.
13 changes: 0 additions & 13 deletions drivers/src/hand_off.rs
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Expand Up @@ -293,19 +293,13 @@ pub struct FirmwareHandoffTable {
pub rtalias_tbs_size: u16,

/// Maximum value RT FW SVN can take.
#[cfg(any(feature = "fmc", feature = "runtime"))]
pub rt_hash_chain_max_svn: u16,

/// Index of RT hash chain value in the Key Vault.
#[cfg(any(feature = "fmc", feature = "runtime"))]
pub rt_hash_chain_kv_hdl: HandOffDataHandle,

/// Reserved for future use.
#[cfg(any(feature = "fmc", feature = "runtime"))]
pub reserved: [u8; 1632],

#[cfg(not(any(feature = "fmc", feature = "runtime")))]
pub reserved: [u8; 1638],
}

impl Default for FirmwareHandoffTable {
Expand Down Expand Up @@ -347,16 +341,9 @@ impl Default for FirmwareHandoffTable {
idev_dice_mldsa_pub_key_load_addr: 0,
rom_info_addr: RomAddr::new(FHT_INVALID_ADDRESS),
rtalias_tbs_size: 0,

#[cfg(any(feature = "fmc", feature = "runtime"))]
rt_hash_chain_max_svn: 0,
#[cfg(any(feature = "fmc", feature = "runtime"))]
rt_hash_chain_kv_hdl: HandOffDataHandle(0),
#[cfg(any(feature = "fmc", feature = "runtime"))]
reserved: [0u8; 1632],

#[cfg(not(any(feature = "fmc", feature = "runtime")))]
reserved: [0u8; 1638],
}
}
}
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24 changes: 0 additions & 24 deletions fmc/src/flow/rt_alias.rs
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Expand Up @@ -111,9 +111,6 @@ impl RtAliasLayer {
.set_pcr_lock(caliptra_common::RT_FW_JOURNEY_PCR);
cprintln!("[alias rt] Lock RT PCRs Done");

cprintln!("[alias rt] Populate DV");
Self::populate_dv(env)?;
cprintln!("[alias rt] Populate DV Done");
report_boot_status(crate::FmcBootStatus::RtMeasurementComplete as u32);

// Retrieve Dice Input Layer from Hand Off and Derive Key
Expand Down Expand Up @@ -183,27 +180,6 @@ impl RtAliasLayer {
}
}

/// Populate Data Vault
///
/// # Arguments
///
/// * `env` - FMC Environment
/// * `hand_off` - HandOff
#[cfg_attr(not(feature = "no-cfi"), cfi_impl_fn)]
pub fn populate_dv(env: &mut FmcEnv) -> CaliptraResult<()> {
let rt_svn = HandOff::rt_svn(env);
let reset_reason = env.soc_ifc.reset_reason();

let rt_min_svn = if reset_reason == ResetReason::ColdReset {
cfi_assert_eq(reset_reason, ResetReason::ColdReset);
rt_svn
} else {
core::cmp::min(rt_svn, HandOff::rt_min_svn(env))
};

HandOff::set_and_lock_rt_min_svn(env, rt_min_svn)
}

fn get_cert_validity_info(
manifest: &caliptra_image_types::ImageManifest,
) -> (NotBefore, NotAfter) {
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56 changes: 0 additions & 56 deletions fmc/src/hand_off.rs
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Expand Up @@ -196,50 +196,6 @@ impl HandOff {
}
}

/// Retrieve runtime minimum SVN.
pub fn rt_min_svn(env: &FmcEnv) -> u32 {
let ds: DataStore =
Self::fht(env)
.rt_min_svn_dv_hdl
.try_into()
.unwrap_or_else(|e: CaliptraError| {
cprintln!("[fht] Invalid RT Min SVN handle");
handle_fatal_error(e.into())
});

// The data store must be a warm reset entry.
match ds {
DataVaultNonSticky4(dv_entry) => env.data_vault.read_warm_reset_entry4(dv_entry),
_ => {
handle_fatal_error(CaliptraError::FMC_HANDOFF_INVALID_PARAM.into());
}
}
}

#[cfg_attr(not(feature = "no-cfi"), cfi_impl_fn)]
pub fn set_and_lock_rt_min_svn(env: &mut FmcEnv, min_svn: u32) -> CaliptraResult<()> {
let ds: DataStore =
Self::fht(env)
.rt_min_svn_dv_hdl
.try_into()
.unwrap_or_else(|e: CaliptraError| {
cprintln!("[fht] Invalid RT Min SVN handle");
handle_fatal_error(e.into())
});

// The data store must be a warm reset entry.
match ds {
DataVaultNonSticky4(dv_entry) => {
env.data_vault.write_warm_reset_entry4(dv_entry, min_svn);
env.data_vault.lock_warm_reset_entry4(dv_entry);
Ok(())
}
_ => {
handle_fatal_error(CaliptraError::FMC_HANDOFF_INVALID_PARAM.into());
}
}
}

/// Store runtime Dice Signature
#[cfg_attr(not(feature = "no-cfi"), cfi_impl_fn)]
pub fn set_rt_dice_signature(env: &mut FmcEnv, sig: &Ecc384Signature) {
Expand Down Expand Up @@ -270,18 +226,6 @@ impl HandOff {
}
}

#[allow(dead_code)]
#[cfg_attr(not(feature = "no-cfi"), cfi_impl_fn)]
pub fn set_rt_hash_chain_max_svn(env: &mut FmcEnv, max_svn: u16) {
Self::fht_mut(env).rt_hash_chain_max_svn = max_svn;
}

#[allow(dead_code)]
#[cfg_attr(not(feature = "no-cfi"), cfi_impl_fn)]
pub fn set_rt_hash_chain_kv_hdl(env: &mut FmcEnv, kv_slot: KeyId) {
Self::fht_mut(env).rt_hash_chain_kv_hdl = Self::key_id_to_handle(kv_slot)
}

/// The FMC CDI is stored in a 32-bit DataVault sticky register.
fn key_id_to_handle(key_id: KeyId) -> HandOffDataHandle {
HandOffDataHandle(((Vault::KeyVault as u32) << 12) | key_id as u32)
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1 change: 1 addition & 0 deletions rom/dev/src/flow/cold_reset/fw_processor.rs
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Expand Up @@ -567,6 +567,7 @@ impl FirmwareProcessor {
data_vault.write_warm_reset_entry48(WarmResetEntry48::RtTci, &info.runtime.digest.into());

data_vault.write_warm_reset_entry4(WarmResetEntry4::RtSvn, info.fw_svn);
data_vault.write_warm_reset_entry4(WarmResetEntry4::RtMinSvn, info.fw_svn); // At cold-boot, min_svn == curr_svn

data_vault.write_warm_reset_entry4(WarmResetEntry4::RtEntryPoint, info.runtime.entry_point);

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4 changes: 4 additions & 0 deletions rom/dev/src/flow/update_reset.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -215,7 +215,11 @@ impl UpdateResetFlow {
fn populate_data_vault(data_vault: &mut DataVault, info: &ImageVerificationInfo) {
data_vault.write_warm_reset_entry48(WarmResetEntry48::RtTci, &info.runtime.digest.into());

let cur_min_svn = data_vault.read_warm_reset_entry4(WarmResetEntry4::RtMinSvn);
let new_min_svn = core::cmp::min(cur_min_svn, info.fw_svn);

data_vault.write_warm_reset_entry4(WarmResetEntry4::RtSvn, info.fw_svn);
data_vault.write_warm_reset_entry4(WarmResetEntry4::RtMinSvn, new_min_svn);

data_vault.write_warm_reset_entry4(WarmResetEntry4::RtEntryPoint, info.runtime.entry_point);

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4 changes: 3 additions & 1 deletion rom/dev/src/lock.rs
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Expand Up @@ -99,7 +99,9 @@ fn lock_common_reg_set(env: &mut RomEnv) {
env.data_vault
.lock_warm_reset_entry4(WarmResetEntry4::RtSvn);

// Do not lock Runtime minimum SVN; FMC will manage this.
// Lock the Firmware Min-SVN in data vault until next reset
env.data_vault
.lock_warm_reset_entry4(WarmResetEntry4::RtMinSvn);

// Lock the Runtime entry point in data vault until next reset
env.data_vault
Expand Down

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