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| 1 | +use core::str; |
| 2 | +use std::fs; |
| 3 | +use std::convert::TryFrom; |
| 4 | +use tss_esapi::{ |
| 5 | + attributes::ObjectAttributesBuilder, |
| 6 | + interface_types::{ |
| 7 | + algorithm::{HashingAlgorithm, PublicAlgorithm, SymmetricMode}, reserved_handles::Hierarchy, |
| 8 | + }, |
| 9 | + structures::{ |
| 10 | + CreatePrimaryKeyResult, Digest, InitialValue, MaxBuffer, PublicBuilder, |
| 11 | + SymmetricCipherParameters, SymmetricDefinitionObject, |
| 12 | + }, |
| 13 | + Context, TctiNameConf, |
| 14 | +}; |
| 15 | + |
| 16 | +fn main() { |
| 17 | + // Create a new TPM context. This reads from the environment variable `TPM2TOOLS_TCTI` or `TCTI` |
| 18 | + // |
| 19 | + // It's recommended you use `TCTI=device:/dev/tpmrm0` for the linux kernel |
| 20 | + // tpm resource manager. |
| 21 | + let mut context = Context::new( |
| 22 | + TctiNameConf::from_environment_variable() |
| 23 | + .expect("Failed to get TCTI / TPM2TOOLS_TCTI from environment. Try `export TCTI=device:/dev/tpmrm0`"), |
| 24 | + ) |
| 25 | + .expect("Failed to create Context"); |
| 26 | + |
| 27 | + // This example won't go over the process to create a new parent. For more detail see `examples/hmac.rs`. |
| 28 | + let primary = create_primary(&mut context); |
| 29 | + |
| 30 | + // Create the AES key. This key exists under the primary key in it's hierarchy |
| 31 | + // and can only be used if the same primary key is recreated from the parameters |
| 32 | + // defined above. |
| 33 | + let object_attributes = ObjectAttributesBuilder::new() |
| 34 | + .with_fixed_tpm(true) |
| 35 | + .with_fixed_parent(true) |
| 36 | + .with_st_clear(false) |
| 37 | + .with_sensitive_data_origin(true) |
| 38 | + .with_user_with_auth(true) |
| 39 | + .with_sign_encrypt(true) |
| 40 | + .with_decrypt(true) |
| 41 | + .build() |
| 42 | + .expect("Failed to build object attributes"); |
| 43 | + |
| 44 | + let key_pub = PublicBuilder::new() |
| 45 | + // This key is a AES key |
| 46 | + .with_public_algorithm(PublicAlgorithm::SymCipher) |
| 47 | + .with_name_hashing_algorithm(HashingAlgorithm::Sha256) |
| 48 | + .with_symmetric_cipher_parameters(SymmetricCipherParameters::new( |
| 49 | + SymmetricDefinitionObject::AES_128_CFB, |
| 50 | + )) |
| 51 | + .with_object_attributes(object_attributes) |
| 52 | + .with_symmetric_cipher_unique_identifier(Digest::default()) |
| 53 | + .build() |
| 54 | + .unwrap(); |
| 55 | + |
| 56 | + let (private, public) = context |
| 57 | + .execute_with_nullauth_session(|ctx| { |
| 58 | + // Create the AES key given our primary key as it's parent. This returns the private |
| 59 | + // and public portions of the key. It's *important* to note that the private component |
| 60 | + // is *encrypted* by a key associated with the primary key. It is not plaintext or |
| 61 | + // leaked in this step. |
| 62 | + ctx.create(primary.key_handle, key_pub, None, None, None, None) |
| 63 | + .map(|key| (key.out_private, key.out_public)) |
| 64 | + }) |
| 65 | + .unwrap(); |
| 66 | + |
| 67 | + // Once the key is created, we have it's parameters in the private and public values. |
| 68 | + // We now need to load it into the tpm so that it can be used. |
| 69 | + // |
| 70 | + // The enc_private and public values can be serialised and persisted - that way they can |
| 71 | + // be reloaded for future use. |
| 72 | + |
| 73 | + // We load the data from a file system file, it can be somewhat large (like a certificate), larger than MaxBuffer::MAX_SIZE |
| 74 | + let initial_data = fs::read("tss-esapi/examples/symmetric_file_encrypt_decrypt_example.txt").expect("could not open data file"); |
| 75 | + |
| 76 | + // We create an initialisation vector, since it is needed for decryption, it should be persisted in a real world use case |
| 77 | + let iv = context |
| 78 | + .execute_with_nullauth_session(|ctx| { |
| 79 | + InitialValue::from_bytes( |
| 80 | + ctx.get_random(16) |
| 81 | + .expect("could not get random bytes for initialisation vector") |
| 82 | + .as_bytes(), |
| 83 | + ) |
| 84 | + }) |
| 85 | + .expect("could not create iv from random bytes"); |
| 86 | + |
| 87 | + // We encrypt the data |
| 88 | + let encrypted_data = context |
| 89 | + .execute_with_nullauth_session(|ctx| { |
| 90 | + let mut encrypted_data = Vec::new(); |
| 91 | + let handle = ctx |
| 92 | + .load(primary.key_handle, private.clone(), public.clone()) |
| 93 | + .expect("could not load child key"); |
| 94 | + |
| 95 | + let mut chunk_iv = iv.clone(); |
| 96 | + |
| 97 | + // This file is larger than the MaxBuffer::MAX_SIZE, so we need to chunk it |
| 98 | + // The iv must be different for every chunk, the encrypt_decrypt_2 function conveniently provide a new one at each iteration |
| 99 | + for chunk in initial_data.chunks(MaxBuffer::MAX_SIZE) { |
| 100 | + let data = MaxBuffer::try_from(Vec::from(chunk)) |
| 101 | + .expect("failed to create data from file buffer chunk"); |
| 102 | + let (enc_data, chunk_iv_out) = ctx.encrypt_decrypt_2( |
| 103 | + handle, // Handle to a symmetric key |
| 104 | + false, // false, indicates that the data should be encrypted |
| 105 | + SymmetricMode::Cfb, // The symmetric mode of the encryption |
| 106 | + data, // The data that is to be encrypted |
| 107 | + chunk_iv, // Initial value needed by the algorithm |
| 108 | + )?; |
| 109 | + chunk_iv = chunk_iv_out; |
| 110 | + encrypted_data.push(enc_data); |
| 111 | + } |
| 112 | + Ok::<Vec<MaxBuffer>, tss_esapi::Error>(encrypted_data) |
| 113 | + }) |
| 114 | + .expect("Call to encrypt_decrypt_2 failed when encrypting data"); |
| 115 | + let encrypted_data = encrypted_data |
| 116 | + .iter() |
| 117 | + .map(|e| e.as_bytes()) |
| 118 | + .collect::<Vec<_>>() |
| 119 | + .concat(); |
| 120 | + |
| 121 | + // Decrypting is exactly the opposite, with the same first iv |
| 122 | + let decrypted_data = context |
| 123 | + .execute_with_nullauth_session(|ctx| { |
| 124 | + let mut decrypted_data = Vec::new(); |
| 125 | + let handle = ctx |
| 126 | + .load(primary.key_handle, private.clone(), public.clone()) |
| 127 | + .expect("could not load child key"); |
| 128 | + |
| 129 | + let mut chunk_iv = iv; |
| 130 | + |
| 131 | + for chunk in encrypted_data.chunks(MaxBuffer::MAX_SIZE) { |
| 132 | + let data = MaxBuffer::try_from(Vec::from(chunk)) |
| 133 | + .expect("failed to create data from encrypted data chunk"); |
| 134 | + let (enc_data, chunk_iv_out) = ctx.encrypt_decrypt_2( |
| 135 | + handle, // Handle to a symmetric key |
| 136 | + true, // true, indicates that the data should be decrypted |
| 137 | + SymmetricMode::Cfb, // The symmetric mode of the encryption |
| 138 | + data, // The data that is to be encrypted |
| 139 | + chunk_iv, // Initial value needed by the algorithm |
| 140 | + )?; |
| 141 | + chunk_iv = chunk_iv_out; |
| 142 | + decrypted_data.push(enc_data); |
| 143 | + } // |
| 144 | + Ok::<Vec<MaxBuffer>, tss_esapi::Error>(decrypted_data) |
| 145 | + }) |
| 146 | + .expect("Call to encrypt_decrypt_2 failed when encrypting data"); |
| 147 | + let decrypted_data = decrypted_data |
| 148 | + .iter() |
| 149 | + .map(|e| e.as_bytes()) |
| 150 | + .collect::<Vec<_>>() |
| 151 | + .concat(); |
| 152 | + |
| 153 | + println!( |
| 154 | + "=== Initial data ===\n\n{}\n\n\n\n", |
| 155 | + str::from_utf8(&initial_data).unwrap() |
| 156 | + ); |
| 157 | + print!(""); |
| 158 | + println!( |
| 159 | + "=== Decrypted data ===\n\n{}", |
| 160 | + str::from_utf8(&decrypted_data).unwrap() |
| 161 | + ); |
| 162 | + // They are the same! |
| 163 | + assert_eq!(initial_data, decrypted_data); |
| 164 | +} |
| 165 | + |
| 166 | +fn create_primary(context: &mut Context) -> CreatePrimaryKeyResult { |
| 167 | + // Create the primary key. A primary key is the "root" of a collection of objects. |
| 168 | + // These other objects are encrypted by the primary key allowing them to persist |
| 169 | + // over a reboot and reloads. |
| 170 | + // |
| 171 | + // A primary key is derived from a seed, and provided that the same inputs are given |
| 172 | + // the same primary key will be derived in the tpm. This means that you do not need |
| 173 | + // to store or save the details of this key - only the parameters of how it was created. |
| 174 | + let object_attributes = ObjectAttributesBuilder::new() |
| 175 | + // Indicate the key can only exist within this tpm and can not be exported. |
| 176 | + .with_fixed_tpm(true) |
| 177 | + // The primary key and it's descendent keys can't be moved to other primary |
| 178 | + // keys. |
| 179 | + .with_fixed_parent(true) |
| 180 | + // The primary key will persist over suspend and resume of the system. |
| 181 | + .with_st_clear(false) |
| 182 | + // The primary key was generated entirely inside the TPM - only this TPM |
| 183 | + // knows it's content. |
| 184 | + .with_sensitive_data_origin(true) |
| 185 | + // This key requires "authentication" to the TPM to access - this can be |
| 186 | + // an HMAC or password session. HMAC sessions are used by default with |
| 187 | + // the "execute_with_nullauth_session" function. |
| 188 | + .with_user_with_auth(true) |
| 189 | + // This key has the ability to decrypt |
| 190 | + .with_decrypt(true) |
| 191 | + // This key may only be used to encrypt or sign objects that are within |
| 192 | + // the TPM - it can not encrypt or sign external data. |
| 193 | + .with_restricted(true) |
| 194 | + .build() |
| 195 | + .expect("Failed to build object attributes"); |
| 196 | + |
| 197 | + let primary_pub = PublicBuilder::new() |
| 198 | + // This key is a symmetric key. |
| 199 | + .with_public_algorithm(PublicAlgorithm::SymCipher) |
| 200 | + .with_name_hashing_algorithm(HashingAlgorithm::Sha256) |
| 201 | + .with_object_attributes(object_attributes) |
| 202 | + .with_symmetric_cipher_parameters(SymmetricCipherParameters::new( |
| 203 | + SymmetricDefinitionObject::AES_128_CFB, |
| 204 | + )) |
| 205 | + .with_symmetric_cipher_unique_identifier(Digest::default()) |
| 206 | + .build() |
| 207 | + .unwrap(); |
| 208 | + |
| 209 | + context |
| 210 | + .execute_with_nullauth_session(|ctx| { |
| 211 | + // Create the key under the "owner" hierarchy. Other hierarchies are platform |
| 212 | + // which is for boot services, null which is ephemeral and resets after a reboot, |
| 213 | + // and endorsement which allows key certification by the TPM manufacturer. |
| 214 | + ctx.create_primary(Hierarchy::Owner, primary_pub, None, None, None, None) |
| 215 | + }) |
| 216 | + .unwrap() |
| 217 | +} |
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