Feat: Add NIST SP800-108 KDF mechanisms

cryptoki/src/mechanism/kbkdf.rs

@@ -0,0 +1,374 @@
+// Copyright 2025 Contributors to the Parsec project.
+// SPDX-License-Identifier: Apache-2.0
+//! Mechanisms of NIST key-based key derive functions (SP 800-108, informally KBKDF)
+//! See: <https://docs.oasis-open.org/pkcs11/pkcs11-curr/v3.0/os/pkcs11-curr-v3.0-os.html#_Toc30061446>
+
+use core::{convert::TryInto, marker::PhantomData, pin::Pin, ptr};
+use std::num::NonZeroUsize;
+
+use cryptoki_sys::{
+    CK_ATTRIBUTE, CK_ATTRIBUTE_PTR, CK_DERIVED_KEY, CK_DERIVED_KEY_PTR, CK_INVALID_HANDLE,
+    CK_OBJECT_HANDLE, CK_OBJECT_HANDLE_PTR, CK_PRF_DATA_PARAM, CK_PRF_DATA_PARAM_PTR,
+    CK_SP800_108_BYTE_ARRAY, CK_SP800_108_COUNTER, CK_SP800_108_COUNTER_FORMAT,
+    CK_SP800_108_DKM_LENGTH, CK_SP800_108_DKM_LENGTH_FORMAT, CK_SP800_108_DKM_LENGTH_SUM_OF_KEYS,
+    CK_SP800_108_DKM_LENGTH_SUM_OF_SEGMENTS, CK_SP800_108_FEEDBACK_KDF_PARAMS,
+    CK_SP800_108_ITERATION_VARIABLE, CK_SP800_108_KDF_PARAMS, CK_ULONG,
+};
+
+use crate::object::{Attribute, ObjectHandle};
+
+use super::MechanismType;
+
+/// Endianness of byte representation of data.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Endianness {
+    /// Little endian.
+    Little,
+    /// Big endian.
+    Big,
+}
+
+/// Defines encoding format for a counter value.
+///
+/// This structure wraps a `CK_SP800_108_COUNTER_FORMAT` structure.
+#[derive(Debug, Clone, Copy)]
+#[repr(transparent)]
+pub struct KbkdfCounterFormat(CK_SP800_108_COUNTER_FORMAT);
+
+impl KbkdfCounterFormat {
+    /// Construct encoding format for KDF's internal counter variable.
+    ///
+    /// # Arguments
+    ///
+    /// * `endianness` - The endianness of the counter's bit representation.
+    ///
+    /// * `width_in_bits` - The number of bits used to represent the counter value.
+    pub fn new(endianness: Endianness, width_in_bits: NonZeroUsize) -> Self {
+        Self(CK_SP800_108_COUNTER_FORMAT {
+            bLittleEndian: (endianness == Endianness::Little).into(),
+            ulWidthInBits: width_in_bits
+                .get()
+                .try_into()
+                .expect("bit width of KBKDF internal counter does not fit in CK_ULONG"),
+        })
+    }
+}
+
+/// Method for calculating length of DKM (derived key material).
+///
+/// Corresponds to CK_SP800_108_DKM_LENGTH_METHOD.
+#[derive(Debug, Clone, Copy)]
+pub enum KbkdfDkmLengthMethod {
+    /// Sum of length of all keys derived by given invocation of KDF.
+    SumOfKeys,
+    /// Sum of length of all segments of output produced by PRF in given invocation of KDF.
+    SumOfSegments,
+}
+
+/// Defines encoding format for DKM (derived key material).
+///
+/// This structure wraps a `CK_SP800_108_DKM_LENGTH_FORMAT` structure.
+#[derive(Debug, Clone, Copy)]
+#[repr(transparent)]
+pub struct KbkdfDkmLengthFormat(CK_SP800_108_DKM_LENGTH_FORMAT);
+
+impl KbkdfDkmLengthFormat {
+    /// Construct encoding format for length value of DKM (derived key material) from KDF.
+    ///
+    /// # Arguments
+    ///
+    /// * `dkm_length_method` - The method used to calculate the DKM length value.
+    ///
+    /// * `endianness` - The endianness of the DKM length value's bit representation.
+    ///
+    /// * `width_in_bits` - The number of bits used to represent the DKM length value.
+    pub fn new(
+        dkm_length_method: KbkdfDkmLengthMethod,
+        endianness: Endianness,
+        width_in_bits: NonZeroUsize,
+    ) -> Self {
+        Self(CK_SP800_108_DKM_LENGTH_FORMAT {
+            dkmLengthMethod: match dkm_length_method {
+                KbkdfDkmLengthMethod::SumOfKeys => CK_SP800_108_DKM_LENGTH_SUM_OF_KEYS,
+                KbkdfDkmLengthMethod::SumOfSegments => CK_SP800_108_DKM_LENGTH_SUM_OF_SEGMENTS,
+            },
+            bLittleEndian: (endianness == Endianness::Little).into(),
+            ulWidthInBits: width_in_bits
+                .get()
+                .try_into()
+                .expect("bit width of KBKDF DKM length value does not fit in CK_ULONG"),
+        })
+    }
+}
+
+/// The type of a segment of input data for the PRF, for a KBKDF operating in feedback- or double pipeline-mode.
+#[derive(Debug, Clone, Copy)]
+pub enum PrfDataParamType<'a> {
+    /// Identifies location of predefined iteration variable in constructed PRF input data.
+    ///
+    /// For counter-mode, this must contain a [`KbkdfCounterFormat`].
+    /// For feedback- and double-pipeline mode, this must contain [`None`].
+    IterationVariable(Option<&'a KbkdfCounterFormat>),
+    /// Identifies location of counter in constructed PRF input data.
+    Counter(&'a KbkdfCounterFormat),
+    /// Identifies location of DKM (derived key material) length value in constructed PRF input data.
+    DkmLength(&'a KbkdfDkmLengthFormat),
+    /// Identifies location and value of byte array of data in constructed PRF input data.
+    ByteArray(&'a [u8]),
+}
+
+/// A segment of input data for the PRF, to be used to construct a sequence of input.
+///
+/// This structure wraps a `CK_PRF_DATA_PARAM` structure.
+///
+/// * [`PrfDataParamType::IterationVariable`] is required for the KDF in all modes.
+///   * In counter-mode, [`PrfDataParamType::IterationVariable`] must contain [`KbkdfCounterFormat`].
+///     In feedback- and double pipeline-mode, it must contain [`None`].
+/// * [`PrfDataParamType::Counter`] must not be present in counter-mode, and can be present at most
+///   once in feedback- and double-pipeline modes.
+/// * [`PrfDataParamType::DkmLength`] can be present at most once, in any mode.
+/// * [`PrfDataParamType::ByteArray`] can be present any amount of times, in any mode.
+#[derive(Debug, Clone, Copy)]
+#[repr(transparent)]
+pub struct PrfDataParam<'a> {
+    inner: CK_PRF_DATA_PARAM,
+    /// Marker type to ensure we don't outlive the data
+    _marker: PhantomData<&'a [u8]>,
+}
+
+impl<'a> PrfDataParam<'a> {
+    /// Construct data parameter for input of the PRF internal to the KBKDF.
+    ///
+    /// # Arguments
+    ///
+    /// * `type_` - The specific type and parameters for the data parameter.
+    pub fn new(type_: PrfDataParamType<'a>) -> Self {
+        Self {
+            inner: match type_ {
+                PrfDataParamType::IterationVariable(None) => CK_PRF_DATA_PARAM {
+                    type_: CK_SP800_108_ITERATION_VARIABLE,
+                    pValue: ptr::null_mut(),
+                    ulValueLen: 0,
+                },
+                PrfDataParamType::IterationVariable(Some(counter_format)) => CK_PRF_DATA_PARAM {
+                    type_: CK_SP800_108_ITERATION_VARIABLE,
+                    pValue: counter_format as *const _ as *mut _,
+                    ulValueLen: size_of::<CK_SP800_108_COUNTER_FORMAT>() as CK_ULONG,
+                },
+                PrfDataParamType::Counter(counter_format) => CK_PRF_DATA_PARAM {
+                    type_: CK_SP800_108_COUNTER,
+                    pValue: counter_format as *const _ as *mut _,
+                    ulValueLen: size_of::<CK_SP800_108_COUNTER_FORMAT>() as CK_ULONG,
+                },
+                PrfDataParamType::DkmLength(dkm_length_format) => CK_PRF_DATA_PARAM {
+                    type_: CK_SP800_108_DKM_LENGTH,
+                    pValue: dkm_length_format as *const _ as *mut _,
+                    ulValueLen: size_of::<CK_SP800_108_DKM_LENGTH_FORMAT>() as CK_ULONG,
+                },
+                PrfDataParamType::ByteArray(data) => CK_PRF_DATA_PARAM {
+                    type_: CK_SP800_108_BYTE_ARRAY,
+                    pValue: data.as_ptr() as *mut _,
+                    ulValueLen: data
+                        .len()
+                        .try_into()
+                        .expect("length of PRF data parameter does not fit in CK_ULONG"),
+                },
+            },
+            _marker: PhantomData,
+        }
+    }
+}
+
+/// Container for information on an additional key to be derived.
+#[derive(Debug)]
+pub struct DerivedKey {
+    template: Pin<Box<[CK_ATTRIBUTE]>>,
+    handle: CK_OBJECT_HANDLE,
+}
+
+impl DerivedKey {
+    /// Construct template for additional key to be derived by KDF.
+    ///
+    /// # Arguments
+    ///
+    /// * `template` - The template for the key to be derived.
+    pub fn new(template: &[Attribute]) -> Self {
+        let template: Box<[CK_ATTRIBUTE]> = template.iter().map(Into::into).collect();
+        let template = Pin::new(template);
+
+        Self {
+            template,
+            handle: CK_INVALID_HANDLE,
+        }
+    }
+
+    /// Return handle for derived key, if it has been created yet
+    pub fn handle(&self) -> Option<ObjectHandle> {
+        if self.handle == CK_INVALID_HANDLE {
+            None
+        } else {
+            Some(ObjectHandle::new(self.handle))
+        }
+    }
+}
+
+impl From<&mut DerivedKey> for CK_DERIVED_KEY {
+    fn from(value: &mut DerivedKey) -> Self {
+        CK_DERIVED_KEY {
+            pTemplate: value.template.as_ptr() as CK_ATTRIBUTE_PTR,
+            ulAttributeCount: value
+                .template
+                .len()
+                .try_into()
+                .expect("number of attributes in template does not fit in CK_ULONG"),
+            phKey: &mut value.handle as CK_OBJECT_HANDLE_PTR,
+        }
+    }
+}
+
+/// NIST SP 800-108 (aka KBKDF) counter and double pipeline-mode parameters.
+///
+/// This structure wraps a `CK_SP800_108_KDF_PARAMS` structure.
+#[derive(Debug)]
+pub struct KbkdfParams<'a> {
+    /// Holds own data so that we have a contiguous memory region to give to backend
+    _additional_derived_keys: Option<Pin<Box<[CK_DERIVED_KEY]>>>,
+
+    inner: CK_SP800_108_KDF_PARAMS,
+    /// Marker type to ensure we don't outlive the data
+    _marker: PhantomData<&'a mut [u8]>,
+}
+
+impl<'a> KbkdfParams<'a> {
+    /// Construct parameters for NIST SP 800-108 KDF (aka KBKDF) pseudorandom function-based key
+    /// derivation function, in counter or double pipeline-mode.
+    ///
+    /// # Arguments
+    ///
+    /// * `prf_mechanism` - The pseudorandom function that underlies the KBKDF operation.
+    ///
+    /// * `prf_data_params` - The sequence of data segments used as input data for the PRF. Requires at least [`PrfDataParamType::IterationVariable`].
+    ///
+    /// * `additional_derived_keys` - Any additional keys to be generated by the KDF from the base key.
+    pub fn new(
+        prf_mechanism: MechanismType,
+        prf_data_params: &'a [PrfDataParam<'a>],
+        additional_derived_keys: Option<&'a mut [DerivedKey]>,
+    ) -> Self {
+        let mut additional_derived_keys = additional_derived_keys
+            .map(|keys| {
+                keys.iter_mut()
+                    .map(Into::into)
+                    .collect::<Box<[CK_DERIVED_KEY]>>()
+            })
+            .map(Pin::new);
+
+        let inner = CK_SP800_108_KDF_PARAMS {
+            prfType: prf_mechanism.into(),
+            ulNumberOfDataParams: prf_data_params
+                .len()
+                .try_into()
+                .expect("number of PRF data parameters does not fit in CK_ULONG"),
+            pDataParams: prf_data_params.as_ptr() as CK_PRF_DATA_PARAM_PTR,
+            ulAdditionalDerivedKeys: additional_derived_keys.as_ref().map_or(0, |keys| {
+                keys.len()
+                    .try_into()
+                    .expect("number of additional derived keys does not fit in CK_ULONG")
+            }),
+            pAdditionalDerivedKeys: additional_derived_keys
+                .as_mut()
+                .map_or(ptr::null_mut(), |keys| {
+                    keys.as_mut_ptr() as CK_DERIVED_KEY_PTR
+                }),
+        };
+
+        Self {
+            _additional_derived_keys: additional_derived_keys,
+
+            inner,
+            _marker: PhantomData,
+        }
+    }
+
+    pub(crate) fn inner(&self) -> &CK_SP800_108_KDF_PARAMS {
+        &self.inner
+    }
+}
+
+/// NIST SP 800-108 (aka KBKDF) feedback-mode parameters.
+///
+/// This structure wraps a `CK_SP800_108_FEEDBACK_KDF_PARAMS` structure.
+#[derive(Debug)]
+pub struct KbkdfFeedbackParams<'a> {
+    /// Holds own data so that we have a contiguous memory region to give to backend
+    _additional_derived_keys: Option<Pin<Box<[CK_DERIVED_KEY]>>>,
+
+    inner: CK_SP800_108_FEEDBACK_KDF_PARAMS,
+    /// Marker type to ensure we don't outlive the data
+    _marker: PhantomData<&'a mut [u8]>,
+}
+
+impl<'a> KbkdfFeedbackParams<'a> {
+    /// Construct parameters for NIST SP 800-108 KDF (aka KBKDF) pseuderandom function-based key
+    /// derivation function, in feedback-mode.
+    ///
+    /// # Arguments
+    ///
+    /// * `prf_mechanism` - The pseudorandom function that underlies the KBKDF operation.
+    ///
+    /// * `prf_data_params` - The sequence of data segments used as input data for the PRF. Requires at least [`PrfDataParamType::IterationVariable`].
+    ///
+    /// * `iv` - The IV to be used for the feedback-mode KDF.
+    ///
+    /// * `additional_derived_keys` - Any additional keys to be generated by the KDF from the base key.
+    pub fn new(
+        prf_mechanism: MechanismType,
+        prf_data_params: &'a [PrfDataParam<'a>],
+        iv: Option<&'a [u8]>,
+        additional_derived_keys: Option<&'a mut [DerivedKey]>,
+    ) -> Self {
+        let mut additional_derived_keys = additional_derived_keys
+            .map(|keys| {
+                keys.iter_mut()
+                    .map(Into::into)
+                    .collect::<Box<[CK_DERIVED_KEY]>>()
+            })
+            .map(Pin::new);
+
+        let inner = CK_SP800_108_FEEDBACK_KDF_PARAMS {
+            prfType: prf_mechanism.into(),
+            ulNumberOfDataParams: prf_data_params
+                .len()
+                .try_into()
+                .expect("number of PRF data parameters does not fit in CK_ULONG"),
+            pDataParams: prf_data_params.as_ptr() as CK_PRF_DATA_PARAM_PTR,
+            ulIVLen: iv.map_or(0, |iv| {
+                iv.len()
+                    .try_into()
+                    .expect("IV length does not fit in CK_ULONG")
+            }),
+            pIV: iv.map_or(ptr::null_mut(), |iv| iv.as_ptr() as *mut _),
+            ulAdditionalDerivedKeys: additional_derived_keys.as_ref().map_or(0, |keys| {
+                keys.len()
+                    .try_into()
+                    .expect("number of additional derived keys does not fit in CK_ULONG")
+            }),
+            pAdditionalDerivedKeys: additional_derived_keys
+                .as_mut()
+                .map_or(ptr::null_mut(), |keys| {
+                    keys.as_mut_ptr() as CK_DERIVED_KEY_PTR
+                }),
+        };
+
+        Self {
+            _additional_derived_keys: additional_derived_keys,
+
+            inner,
+            _marker: PhantomData,
+        }
+    }
+
+    pub(crate) fn inner(&self) -> &CK_SP800_108_FEEDBACK_KDF_PARAMS {
+        &self.inner
+    }
+}