[dice] Add DiceKdf wrapper to libdiced_open_dice
This function will be used to derived the sealing key for
encrypted storage in Microdroid later.
Bug: 267575445
Test: atest libdiced_open_dice_nostd.integration_test \
libdiced_open_dice.integration_test \
diced_open_dice_cbor_test
Change-Id: I7c2e2eb49c3942a3d0c67f076d311a939da754d4
diff --git a/diced/open_dice/src/lib.rs b/diced/open_dice/src/lib.rs
index 9184a44..0efea61 100644
--- a/diced/open_dice/src/lib.rs
+++ b/diced/open_dice/src/lib.rs
@@ -34,6 +34,6 @@
PRIVATE_KEY_SEED_SIZE,
};
pub use error::{check_result, DiceError, Result};
-pub use ops::hash;
+pub use ops::{hash, kdf};
#[cfg(feature = "std")]
pub use retry::{retry_bcc_format_config_descriptor, retry_bcc_main_flow, OwnedDiceArtifacts};
diff --git a/diced/open_dice/src/ops.rs b/diced/open_dice/src/ops.rs
index ca0e341..0eab116 100644
--- a/diced/open_dice/src/ops.rs
+++ b/diced/open_dice/src/ops.rs
@@ -18,7 +18,7 @@
use crate::dice::{Hash, HASH_SIZE};
use crate::error::{check_result, Result};
-use open_dice_cbor_bindgen::DiceHash;
+use open_dice_cbor_bindgen::{DiceHash, DiceKdf};
use std::ptr;
/// Hashes the provided input using DICE's hash function `DiceHash`.
@@ -36,3 +36,23 @@
})?;
Ok(output)
}
+
+/// An implementation of HKDF-SHA512. Derives a key of `derived_key.len()` bytes from `ikm`, `salt`,
+/// and `info`. The derived key is written to the `derived_key`.
+pub fn kdf(ikm: &[u8], salt: &[u8], info: &[u8], derived_key: &mut [u8]) -> Result<()> {
+ // SAFETY: The function writes to the `derived_key`, within the given bounds, and only reads the
+ // input values. The first argument context is not used in this function.
+ check_result(unsafe {
+ DiceKdf(
+ ptr::null_mut(), // context
+ derived_key.len(),
+ ikm.as_ptr(),
+ ikm.len(),
+ salt.as_ptr(),
+ salt.len(),
+ info.as_ptr(),
+ info.len(),
+ derived_key.as_mut_ptr(),
+ )
+ })
+}
diff --git a/diced/open_dice/tests/api_test.rs b/diced/open_dice/tests/api_test.rs
index 5b36f8d..3823bb7 100644
--- a/diced/open_dice/tests/api_test.rs
+++ b/diced/open_dice/tests/api_test.rs
@@ -14,20 +14,32 @@
* limitations under the License.
*/
-use diced_open_dice::{derive_cdi_certificate_id, hash, ID_SIZE};
+use diced_open_dice::{
+ derive_cdi_certificate_id, hash, kdf, HASH_SIZE, ID_SIZE, PRIVATE_KEY_SEED_SIZE,
+};
#[test]
fn hash_succeeds() {
- assert_eq!(
- hash(b"hello world").expect("hash failed"),
- [
- 0x30, 0x9e, 0xcc, 0x48, 0x9c, 0x12, 0xd6, 0xeb, 0x4c, 0xc4, 0x0f, 0x50, 0xc9, 0x02,
- 0xf2, 0xb4, 0xd0, 0xed, 0x77, 0xee, 0x51, 0x1a, 0x7c, 0x7a, 0x9b, 0xcd, 0x3c, 0xa8,
- 0x6d, 0x4c, 0xd8, 0x6f, 0x98, 0x9d, 0xd3, 0x5b, 0xc5, 0xff, 0x49, 0x96, 0x70, 0xda,
- 0x34, 0x25, 0x5b, 0x45, 0xb0, 0xcf, 0xd8, 0x30, 0xe8, 0x1f, 0x60, 0x5d, 0xcf, 0x7d,
- 0xc5, 0x54, 0x2e, 0x93, 0xae, 0x9c, 0xd7, 0x6f
- ]
- );
+ const EXPECTED_HASH: [u8; HASH_SIZE] = [
+ 0x30, 0x9e, 0xcc, 0x48, 0x9c, 0x12, 0xd6, 0xeb, 0x4c, 0xc4, 0x0f, 0x50, 0xc9, 0x02, 0xf2,
+ 0xb4, 0xd0, 0xed, 0x77, 0xee, 0x51, 0x1a, 0x7c, 0x7a, 0x9b, 0xcd, 0x3c, 0xa8, 0x6d, 0x4c,
+ 0xd8, 0x6f, 0x98, 0x9d, 0xd3, 0x5b, 0xc5, 0xff, 0x49, 0x96, 0x70, 0xda, 0x34, 0x25, 0x5b,
+ 0x45, 0xb0, 0xcf, 0xd8, 0x30, 0xe8, 0x1f, 0x60, 0x5d, 0xcf, 0x7d, 0xc5, 0x54, 0x2e, 0x93,
+ 0xae, 0x9c, 0xd7, 0x6f,
+ ];
+ assert_eq!(EXPECTED_HASH, hash(b"hello world").expect("hash failed"));
+}
+
+#[test]
+fn kdf_succeeds() {
+ let mut derived_key = [0u8; PRIVATE_KEY_SEED_SIZE];
+ kdf(b"myInitialKeyMaterial", b"mySalt", b"myInfo", &mut derived_key).unwrap();
+ const EXPECTED_DERIVED_KEY: [u8; PRIVATE_KEY_SEED_SIZE] = [
+ 0x91, 0x9b, 0x8d, 0x29, 0xc4, 0x1b, 0x93, 0xd7, 0xeb, 0x09, 0xfa, 0xd7, 0xc9, 0x87, 0xb0,
+ 0xd1, 0xcc, 0x26, 0xef, 0x07, 0x83, 0x42, 0xcf, 0xa3, 0x45, 0x0a, 0x57, 0xe9, 0x19, 0x86,
+ 0xef, 0x48,
+ ];
+ assert_eq!(EXPECTED_DERIVED_KEY, derived_key);
}
#[test]