Skip to content

Commit

Permalink
Refactor of key_derivation
Browse files Browse the repository at this point in the history 
Signed-off-by: Samuel Bailey <samuel.bailey@arm.com>
  • Loading branch information
@sbailey-arm
sbailey-arm committed Aug 12, 2020
1 parent a007a30 commit d3a903c
Show file tree
Hide file tree
Showing 3 changed files with 206 additions and 19 deletions.
4 changes: 2 additions & 2 deletions psa-crypto/src/operations/key_derivation.rs
View file
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
76 changes: 59 additions & 17 deletions psa-crypto/src/types/key_derivation.rs
View file
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 @@ -207,28 +222,55 @@ 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],
},
}

impl<'a> From<Input<'a>> for InputSecret<'a> {
fn from(input: Input<'a>) -> Self {
InputSecret::<'a>::Input(input)
}
}

#[cfg(feature = "interface")]
impl TryFrom<Operation<'_>> for psa_crypto_sys::psa_key_derivation_operation_t {
type Error = Error;

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
145 changes: 145 additions & 0 deletions psa-crypto/tests/key_derivation.rs
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,145 @@
use psa_crypto::operations::{key_derivation, key_management};
use psa_crypto::types::algorithm::{Hash, KeyAgreement, KeyDerivation, RawKeyAgreement};
use psa_crypto::types::key::{Attributes, EccFamily, Lifetime, Policy, Type, UsageFlags};
use psa_crypto::types::key_derivation::{Input, InputSecret, Inputs, Operation};

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,
];

#[test]
fn output_key() {
const KEY_DATA: [u8; 23] = [0; 23];
let attributes = Attributes {
key_type: Type::Derive,
bits: 0,
lifetime: Lifetime::Volatile,
policy: Policy {
usage_flags: UsageFlags {
derive: true,
..Default::default()
},
permitted_algorithms: KeyDerivation::Hkdf {
hash_alg: Hash::Sha256,
}
.into(),
},
};

let 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 my_key = key_management::import(attributes, None, &KEY_DATA).unwrap();
let info = vec![20; 0x3f];
let operation = Operation {
inputs: Inputs::Hkdf {
hash_alg: Hash::Sha256,
salt: None,
secret: InputSecret::Input(Input::Key(my_key)),
info: Input::Bytes(&info),
},
capacity: None,
};
let _new_key = key_derivation::output_key(operation, derived_key_attributes, None).unwrap();
}

#[test]
#[ignore]
fn output_key_with_key_agreement() {
let key_agreement_alg = RawKeyAgreement::Ecdh;
let 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 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 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 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();
}

0 comments on commit d3a903c

Please sign in to comment.