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Refactor of key_derivation
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Signed-off-by: Samuel Bailey <samuel.bailey@arm.com>
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@sbailey-arm
sbailey-arm committed Aug 10, 2020
1 parent 1067036 commit 400b1fa
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Showing 2 changed files with 134 additions and 19 deletions.
83 changes: 81 additions & 2 deletions psa-crypto/src/operations/key_derivation.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ use core::convert::{TryFrom, TryInto};
/// use psa_crypto::operations::{key_derivation, key_management};
/// use psa_crypto::types::key::{Attributes, Type, Lifetime, Policy, UsageFlags};
/// use psa_crypto::types::algorithm::{Hash, KeyDerivation};
/// use psa_crypto::types::key_derivation::{Operation, Inputs, Input};
/// use psa_crypto::types::key_derivation::{Operation, Inputs, Input, InputSecret};
///
/// # const KEY_DATA: [u8; 23] = [0; 23];
/// # let mut attributes = Attributes {
Expand Down Expand Up @@ -59,7 +59,7 @@ use core::convert::{TryFrom, TryInto};
/// inputs: Inputs::Hkdf {
/// hash_alg: Hash::Sha256,
/// salt: None,
/// secret: Input::Key(my_key),
/// secret: InputSecret::Input(Input::Key(my_key)),
/// info: Input::Bytes(&info),
/// },
/// capacity: None,
Expand Down Expand Up @@ -94,3 +94,82 @@ pub fn output_key(operation: Operation, attributes: Attributes, id: Option<u32>)
key_deriv_res?; // All other error can now return after abort
complete_new_key_operation(attributes.lifetime, id, handle_for_new_key)
}

/*/// This function calculates output bytes from a key derivation algorithm and returns those bytes.
/// # Example
///
/// ```
/// use psa_crypto::operations::{key_derivation, key_management, key_agreement};
/// use psa_crypto::types::key::{Attributes, Type, Lifetime, Policy, UsageFlags, EccFamily};
/// use psa_crypto::types::algorithm::{Hash, KeyDerivation, KeyAgreement, RawKeyAgreement};
/// use psa_crypto::types::key_derivation::{Operation, Inputs, Input, InputSecret};
/// # const PEER_PUBLIC_KEY: [u8; 65] = [0x04, 0xd1, 0x2d, 0xfb, 0x52, 0x89, 0xc8, 0xd4, 0xf8, 0x12, 0x08, 0xb7, 0x02,
/// # 0x70, 0x39, 0x8c, 0x34, 0x22, 0x96, 0x97, 0x0a, 0x0b, 0xcc, 0xb7, 0x4c, 0x73, 0x6f, 0xc7, 0x55, 0x44, 0x94, 0xbf, 0x63,
/// # 0x56, 0xfb, 0xf3, 0xca, 0x36, 0x6c, 0xc2, 0x3e, 0x81, 0x57, 0x85, 0x4c, 0x13, 0xc5, 0x8d, 0x6a, 0xac, 0x23, 0xf0, 0x46,
/// # 0xad, 0xa3, 0x0f, 0x83, 0x53, 0xe7, 0x4f, 0x33, 0x03, 0x98, 0x72, 0xab];
/// # const PRIVATE_KEY_DATA: [u8; 32] = [0xc8, 0x8f, 0x01, 0xf5, 0x10, 0xd9, 0xac, 0x3f, 0x70, 0xa2, 0x92, 0xda, 0xa2,
/// # 0x31, 0x6d, 0xe5, 0x44, 0xe9, 0xaa, 0xb8, 0xaf, 0xe8, 0x40, 0x49, 0xc6, 0x2a, 0x9c, 0x57, 0x86, 0x2d, 0x14, 0x33];
/// # let key_agreement_alg = RawKeyAgreement::Ecdh;
/// # let mut key_agr_attributes = Attributes {
/// # key_type: Type::EccKeyPair {curve_family: EccFamily::SecpR1 },
/// # bits: 0,
/// # lifetime: Lifetime::Volatile,
/// # policy: Policy {
/// # usage_flags: UsageFlags {
/// # derive: true,
/// # ..Default::default()
/// # },
/// # permitted_algorithms: KeyAgreement::WithKeyDerivation {ka_alg: key_agreement_alg, kdf_alg: KeyDerivation::Hkdf {hash_alg: Hash::Sha256}}.into(),
/// # },
/// # };
///
/// # const KEY_DATA: [u8; 23] = [0; 23];
/// # let mut attributes = Attributes {
/// # key_type: Type::RawData,
/// # bits: 0,
/// # lifetime: Lifetime::Volatile,
/// # policy: Policy {
/// # usage_flags: UsageFlags {
/// # derive: true,
/// # ..Default::default()
/// # },
/// # permitted_algorithms: KeyAgreement::WithKeyDerivation {ka_alg: key_agreement_alg, kdf_alg: KeyDerivation::Hkdf {hash_alg: Hash::Sha256}}.into(),
/// # }
/// # };
///
/// # let mut derived_key_attributes = Attributes {
/// # key_type: Type::RawData,
/// # bits: 8,
/// # lifetime: Lifetime::Volatile,
/// # policy: Policy {
/// # usage_flags: UsageFlags {
/// # derive: true,
/// # ..Default::default()
/// # },
/// # permitted_algorithms: KeyDerivation::Hkdf {
/// # hash_alg: Hash::Sha256,
/// # }.into()
/// # }
/// # };
///
/// psa_crypto::init().unwrap();
/// let key_agreement_key = key_management::import(key_agr_attributes, None, &PRIVATE_KEY_DATA).unwrap();
/// let my_key = key_management::import(attributes, None, &KEY_DATA).unwrap();
/// //let mut output = vec![0; 1024];
/// //let _size = key_agreement::raw_key_agreement(key_agreement_alg, key_agreement_key, &PEER_PUBLIC_KEY, &mut output).unwrap();
/// let info = vec![20; 0x3f];
/// let mut operation = Operation {
/// inputs: Inputs::Hkdf {
/// hash_alg: Hash::Sha256,
/// salt: None,
/// secret: InputSecret::KeyAgreement {
/// alg: key_agreement_alg,
/// private_key: key_agreement_key,
/// peer_key: &PEER_PUBLIC_KEY,
/// },
/// info: Input::Key(my_key),
/// },
/// capacity: None,
/// };
/// let _new_key = key_derivation::output_key(operation, derived_key_attributes, None).unwrap();*/
// pub fn output_key(operation: Operation, attributes: Attributes, id: Option<u32>) -> Result<Id> {}
70 changes: 53 additions & 17 deletions psa-crypto/src/types/key_derivation.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@

//! # PSA Key Derivation Operation types
use super::algorithm::{Hash, KeyDerivation};
use super::algorithm::{Hash, KeyDerivation, RawKeyAgreement};
use super::key::Id;
#[cfg(feature = "interface")]
use super::status::{Error, Result, Status};
Expand Down Expand Up @@ -32,7 +32,7 @@ pub enum Inputs<'a> {
/// Secret, used in the "extract" step. This is typically a key of type `Derive` , or the shared secret
/// resulting from a key agreement, using `Input::KeyAgreement`.
/// Must be a key or key agreement input if used with `psa_key_derivation_output_key`.
secret: Input<'a>,
secret: InputSecret<'a>,
/// Info, used in the "expand" step. Typically a direct input, can also be a key of type `RawData`.
info: Input<'a>,
},
Expand All @@ -45,7 +45,7 @@ pub enum Inputs<'a> {
/// Secret, used in the "extract" step. This is typically a key of type `Derive` , or the shared secret
/// resulting from a key agreement, using `Input::KeyAgreement`.
/// Must be a key or key agreement input if used with `psa_key_derivation_output_key`.
secret: Input<'a>,
secret: InputSecret<'a>,
/// Label. Typically a direct input, can also be a key of type `RawData`.
label: Input<'a>,
},
Expand All @@ -59,7 +59,7 @@ pub enum Inputs<'a> {
/// resulting from a key agreement, using `Input::KeyAgreement`.
/// Must be a key or key agreement input if used with `psa_key_derivation_output_key`.
/// Must not be larger than `PSA_TLS12_PSK_TO_MS_PSK_MAX_SIZE`.
secret: Input<'a>,
secret: InputSecret<'a>,
/// Label. Typically a direct input, can also be a key of type `RawData`.
label: Input<'a>,
},
Expand Down Expand Up @@ -133,7 +133,7 @@ impl Inputs<'_> {
if let Some(salt) = salt {
Inputs::apply_input_step_to_op(op, DerivationStep::Salt, salt)?;
}
Inputs::apply_input_step_to_op(op, DerivationStep::Secret, secret)?;
Inputs::apply_input_secret_step_to_op(op, secret)?;
Inputs::apply_input_step_to_op(op, DerivationStep::Info, info)
}
Inputs::Tls12Prf {
Expand All @@ -149,7 +149,7 @@ impl Inputs<'_> {
..
} => {
Inputs::apply_input_step_to_op(op, DerivationStep::Seed, seed)?;
Inputs::apply_input_step_to_op(op, DerivationStep::Secret, secret)?;
Inputs::apply_input_secret_step_to_op(op, secret)?;
Inputs::apply_input_step_to_op(op, DerivationStep::Label, label)
}
}
Expand Down Expand Up @@ -179,22 +179,37 @@ impl Inputs<'_> {
.to_result()?;
key_id.close_handle(handle)
}
Input::KeyAgreement {
}
}

#[cfg(feature = "interface")]
fn apply_input_secret_step_to_op(
op: &mut psa_crypto_sys::psa_key_derivation_operation_t,
secret: &InputSecret,
) -> Result<()> {
match secret {
InputSecret::Input(input) => {
Inputs::apply_input_step_to_op(op, DerivationStep::Secret, &input)
}
InputSecret::KeyAgreement {
private_key,
peer_key,
..
} => {
let handle = private_key.handle()?;
Status::from(unsafe {
let key_agreement_res = Status::from(unsafe {
psa_crypto_sys::psa_key_derivation_key_agreement(
op,
step.into(),
DerivationStep::Secret.into(),
handle,
peer_key.as_ptr(),
(**peer_key).as_ptr(),
peer_key.len(),
)
})
.to_result()?;
private_key.close_handle(handle)
.to_result();
let close_handle_res = private_key.close_handle(handle);
key_agreement_res?;
close_handle_res
}
}
}
Expand All @@ -207,11 +222,20 @@ pub enum Input<'a> {
Bytes(&'a [u8]),
/// Key input for key derivation
Key(Id),
}

/// Enumeration of supported input data for different input steps
#[derive(Debug, Clone, Copy)]
pub enum InputSecret<'a> {
/// Regular input of bytes or a key ID
Input(Input<'a>),
/// Output of a key agreement
KeyAgreement {
/// Key agreement algorithm to use
alg: RawKeyAgreement,
/// Private key to use in key agreement
private_key: Id,
/// Public key data of peer key to use. Must be in the same format that `psa_import_key()` accepts for the public key
/// Public key data of peer key to use. Must be in the same format that `key_management::import` accepts for the public key
/// corresponding to the type of private key.
peer_key: &'a [u8],
},
Expand All @@ -224,11 +248,23 @@ impl TryFrom<Operation<'_>> for psa_crypto_sys::psa_key_derivation_operation_t {
fn try_from(operation: Operation) -> Result<Self> {
let mut op = psa_crypto_sys::psa_key_derivation_operation_init();
let mut setup_deriv_op = || -> Result<()> {
let mut key_derivation_alg: psa_crypto_sys::psa_algorithm_t =
operation.inputs.key_derivation().into();

// If key agreement is used as the input for secret step, extract key agreement alg and combine it with key derivation alg
let secret = match operation.inputs {
Inputs::Hkdf { secret, .. }
| Inputs::Tls12Prf { secret, .. }
| Inputs::Tls12PskToMs { secret, .. } => secret,
};
if let InputSecret::KeyAgreement { alg, .. } = secret {
key_derivation_alg = unsafe {
psa_crypto_sys::PSA_ALG_KEY_AGREEMENT(alg.into(), key_derivation_alg)
};
}

Status::from(unsafe {
psa_crypto_sys::psa_key_derivation_setup(
&mut op,
operation.inputs.key_derivation().into(),
)
psa_crypto_sys::psa_key_derivation_setup(&mut op, key_derivation_alg)
})
.to_result()?;
operation.inputs.apply_inputs_to_op(&mut op)
Expand Down

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