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ek abstraction: align with TCG EK Credential Profile
Signed-off-by: Thore Sommer <[email protected]>
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  • tss-esapi/src/abstraction

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+118
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‎tss-esapi/src/abstraction/ek.rs‎

Lines changed: 118 additions & 48 deletions
Original file line numberDiff line numberDiff line change
@@ -32,6 +32,28 @@ const ECC_P256_SM2_EK_CERTIFICATE_NV_INDEX: u32 = 0x01c0001a;
3232
const RSA_3072_EK_CERTIFICATE_NV_INDEX: u32 = 0x01c0001c;
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const RSA_4096_EK_CERTIFICATE_NV_INDEX: u32 = 0x01c0001e;
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35+
// Source: TCG EK Credential Profile for TPM Family 2.0; Level 0 Version 2.3 Revision 2
36+
// Section B.3 and B.4
37+
const AUTHPOLICY_SHA256: [u8; 32] = [
38+
0x83, 0x71, 0x97, 0x67, 0x44, 0x84, 0xb3, 0xf8, 0x1a, 0x90, 0xcc, 0x8d, 0x46, 0xa5, 0xd7, 0x24,
39+
0xfd, 0x52, 0xd7, 0x6e, 0x06, 0x52, 0x0b, 0x64, 0xf2, 0xa1, 0xda, 0x1b, 0x33, 0x14, 0x69, 0xaa,
40+
];
41+
const AUTHPOLICY_SHA384: [u8; 48] = [
42+
0xb2, 0x6e, 0x7d, 0x28, 0xd1, 0x1a, 0x50, 0xbc, 0x53, 0xd8, 0x82, 0xbc, 0xf5, 0xfd, 0x3a, 0x1a,
43+
0x07, 0x41, 0x48, 0xbb, 0x35, 0xd3, 0xb4, 0xe4, 0xcb, 0x1c, 0x0a, 0xd9, 0xbd, 0xe4, 0x19, 0xca,
44+
0xcb, 0x47, 0xba, 0x09, 0x69, 0x96, 0x46, 0x15, 0x0f, 0x9f, 0xc0, 0x00, 0xf3, 0xf8, 0x0e, 0x12,
45+
];
46+
const AUTHPOLICY_SHA512: [u8; 64] = [
47+
0xb8, 0x22, 0x1c, 0xa6, 0x9e, 0x85, 0x50, 0xa4, 0x91, 0x4d, 0xe3, 0xfa, 0xa6, 0xa1, 0x8c, 0x07,
48+
0x2c, 0xc0, 0x12, 0x08, 0x07, 0x3a, 0x92, 0x8d, 0x5d, 0x66, 0xd5, 0x9e, 0xf7, 0x9e, 0x49, 0xa4,
49+
0x29, 0xc4, 0x1a, 0x6b, 0x26, 0x95, 0x71, 0xd5, 0x7e, 0xdb, 0x25, 0xfb, 0xdb, 0x18, 0x38, 0x42,
50+
0x56, 0x08, 0xb4, 0x13, 0xcd, 0x61, 0x6a, 0x5f, 0x6d, 0xb5, 0xb6, 0x07, 0x1a, 0xf9, 0x9b, 0xea,
51+
];
52+
const AUTHPOLICY_SM3_256: [u8; 32] = [
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0x16, 0x78, 0x60, 0xa3, 0x5f, 0x2c, 0x5c, 0x35, 0x67, 0xf9, 0xc9, 0x27, 0xac, 0x56, 0xc0, 0x32,
54+
0xf3, 0xb3, 0xa6, 0x46, 0x2f, 0x8d, 0x03, 0x79, 0x98, 0xe7, 0xa1, 0x0f, 0x77, 0xfa, 0x45, 0x4a,
55+
];
56+
3557
/// Get the [`Public`] representing a default Endorsement Key
3658
///
3759
/// Source: TCG EK Credential Profile for TPM Family 2.0; Level 0 Version 2.3 Revision 2
@@ -42,12 +64,19 @@ pub fn create_ek_public_from_default_template<IKC: IntoKeyCustomization>(
4264
) -> Result<Public> {
4365
let key_customization = key_customization.into_key_customization();
4466

67+
// user_with_auth is not set for the lower profiles (RSA 20248 and ECC P256)
68+
let user_with_auth = match alg {
69+
AsymmetricAlgorithmSelection::Rsa(RsaKeyBits::Rsa2048)
70+
| AsymmetricAlgorithmSelection::Ecc(EccCurve::NistP256) => false,
71+
_ => true,
72+
};
73+
4574
let obj_attrs_builder = ObjectAttributesBuilder::new()
4675
.with_fixed_tpm(true)
4776
.with_st_clear(false)
4877
.with_fixed_parent(true)
4978
.with_sensitive_data_origin(true)
50-
.with_user_with_auth(false)
79+
.with_user_with_auth(user_with_auth)
5180
.with_admin_with_policy(true)
5281
.with_no_da(false)
5382
.with_encrypted_duplication(false)
@@ -62,54 +91,95 @@ pub fn create_ek_public_from_default_template<IKC: IntoKeyCustomization>(
6291
}
6392
.build()?;
6493

65-
// TPM2_PolicySecret(TPM_RH_ENDORSEMENT)
66-
// With 32 null-bytes attached, because of the type of with_auth_policy
67-
let authpolicy: [u8; 64] = [
68-
0x83, 0x71, 0x97, 0x67, 0x44, 0x84, 0xb3, 0xf8, 0x1a, 0x90, 0xcc, 0x8d, 0x46, 0xa5, 0xd7,
69-
0x24, 0xfd, 0x52, 0xd7, 0x6e, 0x06, 0x52, 0x0b, 0x64, 0xf2, 0xa1, 0xda, 0x1b, 0x33, 0x14,
70-
0x69, 0xaa, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
71-
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
72-
0x00, 0x00, 0x00, 0x00,
73-
];
74-
7594
let key_builder = match alg {
76-
AsymmetricAlgorithmSelection::Rsa(key_bits) => PublicBuilder::new()
77-
.with_public_algorithm(PublicAlgorithm::Rsa)
78-
.with_name_hashing_algorithm(HashingAlgorithm::Sha256)
79-
.with_object_attributes(obj_attrs)
80-
.with_auth_policy(Digest::try_from(authpolicy[0..32].to_vec())?)
81-
.with_rsa_parameters(
82-
PublicRsaParametersBuilder::new()
83-
.with_symmetric(SymmetricDefinitionObject::AES_128_CFB)
84-
.with_scheme(RsaScheme::Null)
85-
.with_key_bits(key_bits)
86-
.with_exponent(RsaExponent::default())
87-
.with_is_signing_key(obj_attrs.sign_encrypt())
88-
.with_is_decryption_key(obj_attrs.decrypt())
89-
.with_restricted(obj_attrs.decrypt())
90-
.build()?,
91-
)
92-
.with_rsa_unique_identifier(PublicKeyRsa::new_empty_with_size(RsaKeyBits::Rsa2048)),
93-
AsymmetricAlgorithmSelection::Ecc(ecc_curve) => PublicBuilder::new()
94-
.with_public_algorithm(PublicAlgorithm::Ecc)
95-
.with_name_hashing_algorithm(HashingAlgorithm::Sha256)
96-
.with_object_attributes(obj_attrs)
97-
.with_auth_policy(Digest::try_from(authpolicy[0..32].to_vec())?)
98-
.with_ecc_parameters(
99-
PublicEccParametersBuilder::new()
100-
.with_symmetric(SymmetricDefinitionObject::AES_128_CFB)
101-
.with_ecc_scheme(EccScheme::Null)
102-
.with_curve(ecc_curve)
103-
.with_key_derivation_function_scheme(KeyDerivationFunctionScheme::Null)
104-
.with_is_signing_key(obj_attrs.sign_encrypt())
105-
.with_is_decryption_key(obj_attrs.decrypt())
106-
.with_restricted(obj_attrs.decrypt())
107-
.build()?,
108-
)
109-
.with_ecc_unique_identifier(EccPoint::new(
110-
EccParameter::try_from(vec![0u8; 32])?,
111-
EccParameter::try_from(vec![0u8; 32])?,
112-
)),
95+
AsymmetricAlgorithmSelection::Rsa(key_bits) => {
96+
let (hash_alg, authpolicy, symmetric) = match key_bits {
97+
RsaKeyBits::Rsa2048 => (
98+
HashingAlgorithm::Sha256,
99+
AUTHPOLICY_SHA256.into(),
100+
SymmetricDefinitionObject::AES_128_CFB,
101+
),
102+
RsaKeyBits::Rsa3072 | RsaKeyBits::Rsa4096 => (
103+
HashingAlgorithm::Sha384,
104+
AUTHPOLICY_SHA384.into(),
105+
SymmetricDefinitionObject::AES_256_CFB,
106+
),
107+
// Other key sizes are not specified in the spec, so fall back to default RSA profile
108+
_ => (
109+
HashingAlgorithm::Sha256,
110+
AUTHPOLICY_SHA256.into(),
111+
SymmetricDefinitionObject::AES_128_CFB,
112+
),
113+
};
114+
115+
PublicBuilder::new()
116+
.with_public_algorithm(PublicAlgorithm::Rsa)
117+
.with_name_hashing_algorithm(hash_alg)
118+
.with_object_attributes(obj_attrs)
119+
.with_auth_policy(authpolicy)
120+
.with_rsa_parameters(
121+
PublicRsaParametersBuilder::new()
122+
.with_symmetric(symmetric)
123+
.with_scheme(RsaScheme::Null)
124+
.with_key_bits(key_bits)
125+
.with_exponent(RsaExponent::default())
126+
.with_is_signing_key(obj_attrs.sign_encrypt())
127+
.with_is_decryption_key(obj_attrs.decrypt())
128+
.with_restricted(obj_attrs.decrypt())
129+
.build()?,
130+
)
131+
.with_rsa_unique_identifier(PublicKeyRsa::new_empty_with_size(RsaKeyBits::Rsa2048))
132+
}
133+
AsymmetricAlgorithmSelection::Ecc(ecc_curve) => {
134+
let (hash_alg, authpolicy, symmetric) = match ecc_curve {
135+
EccCurve::NistP256 => (
136+
HashingAlgorithm::Sha256,
137+
AUTHPOLICY_SHA256.into(),
138+
SymmetricDefinitionObject::AES_128_CFB,
139+
),
140+
EccCurve::NistP384 => (
141+
HashingAlgorithm::Sha384,
142+
AUTHPOLICY_SHA384.into(),
143+
SymmetricDefinitionObject::AES_256_CFB,
144+
),
145+
EccCurve::NistP521 => (
146+
HashingAlgorithm::Sha512,
147+
AUTHPOLICY_SHA512.into(),
148+
SymmetricDefinitionObject::AES_256_CFB,
149+
),
150+
EccCurve::Sm2P256 => (
151+
HashingAlgorithm::Sm3_256,
152+
AUTHPOLICY_SM3_256.into(),
153+
SymmetricDefinitionObject::SM4_128_CFB,
154+
),
155+
// Other curves are not specicied in the spec, so fallback on default ECC profile
156+
_ => (
157+
HashingAlgorithm::Sha256,
158+
Digest::try_from(AUTHPOLICY_SHA256.to_vec())?,
159+
SymmetricDefinitionObject::AES_128_CFB,
160+
),
161+
};
162+
PublicBuilder::new()
163+
.with_public_algorithm(PublicAlgorithm::Ecc)
164+
.with_name_hashing_algorithm(hash_alg)
165+
.with_object_attributes(obj_attrs)
166+
.with_auth_policy(authpolicy)
167+
.with_ecc_parameters(
168+
PublicEccParametersBuilder::new()
169+
.with_symmetric(symmetric)
170+
.with_ecc_scheme(EccScheme::Null)
171+
.with_curve(ecc_curve)
172+
.with_key_derivation_function_scheme(KeyDerivationFunctionScheme::Null)
173+
.with_is_signing_key(obj_attrs.sign_encrypt())
174+
.with_is_decryption_key(obj_attrs.decrypt())
175+
.with_restricted(obj_attrs.decrypt())
176+
.build()?,
177+
)
178+
.with_ecc_unique_identifier(EccPoint::new(
179+
EccParameter::try_from(vec![0u8; 32])?,
180+
EccParameter::try_from(vec![0u8; 32])?,
181+
))
182+
}
113183
};
114184

115185
let key_builder = if let Some(ref k) = key_customization {

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