refactor: use constants instead of magic numbers

openwsn-berkeley · Oct 25, 2023 · 774c8ca · 774c8ca
1 parent 439c326
commit 774c8ca
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Showing 2 changed files with 18 additions and 3 deletions.
diff --git a/consts/src/lib.rs b/consts/src/lib.rs
@@ -10,9 +10,12 @@ mod consts {
     // TODO: find a way to configure the buffer size
     // need 128 to handle EAD fields, and 256 for the EAD_1 voucher
     pub const MAX_MESSAGE_SIZE_LEN: usize = 128 + 64;
-    pub const MAX_EAD_SIZE_LEN: usize = 64;
     pub type EADMessageBuffer = EdhocMessageBuffer; // TODO: make it of size MAX_EAD_SIZE_LEN
+
+    pub const MAX_EAD_SIZE_LEN: usize = 64;
     pub const EAD_ZEROCONF_LABEL: u8 = 0x1; // NOTE: in lake-authz-draft-02 it is still TBD1
+    pub const EAD_ZEROCONF_INFO_K_1_LABEL: u8 = 0x0;
+    pub const EAD_ZEROCONF_INFO_IV_1_LABEL: u8 = 0x1;
 
     pub const ID_CRED_LEN: usize = 4;
     pub const SUITES_LEN: usize = 9;

diff --git a/ead/edhoc-ead-zeroconf/src/lib.rs b/ead/edhoc-ead-zeroconf/src/lib.rs
@@ -174,13 +174,25 @@ fn compute_prk(a: &BytesP256ElemLen, g_b: &BytesP256ElemLen) -> BytesHashLen {
 fn compute_k_1_iv_1(prk: &BytesHashLen) -> (BytesCcmKeyLen, BytesCcmIvLen) {
     // K_1 = EDHOC-Expand(PRK, info = (0, h'', AES_CCM_KEY_LEN), length)
     let mut k_1: BytesCcmKeyLen = [0x00; AES_CCM_KEY_LEN];
-    let k_1_buf = edhoc_kdf(prk, 0, &[0x00; MAX_KDF_CONTEXT_LEN], 0, AES_CCM_KEY_LEN);
+    let k_1_buf = edhoc_kdf(
+        prk,
+        EAD_ZEROCONF_INFO_K_1_LABEL,
+        &[0x00; MAX_KDF_CONTEXT_LEN],
+        0,
+        AES_CCM_KEY_LEN,
+    );
     k_1[..].copy_from_slice(&k_1_buf[..AES_CCM_KEY_LEN]);
 
     // IV_1 = EDHOC-Expand(PRK, info = (1, h'', AES_CCM_KEY_LEN), length)
     let mut iv_1: BytesCcmIvLen = [0x00; AES_CCM_IV_LEN];
     // NOTE (FIXME?): here we actually generate AES_CCM_KEY_LEN bytes, but then we only use AES_CCM_IV_LEN of them (next line)
-    let iv_1_buf = edhoc_kdf(prk, 1, &[0x00; MAX_KDF_CONTEXT_LEN], 0, AES_CCM_KEY_LEN);
+    let iv_1_buf = edhoc_kdf(
+        prk,
+        EAD_ZEROCONF_INFO_IV_1_LABEL,
+        &[0x00; MAX_KDF_CONTEXT_LEN],
+        0,
+        AES_CCM_KEY_LEN,
+    );
     iv_1[..].copy_from_slice(&iv_1_buf[..AES_CCM_IV_LEN]);
 
     (k_1, iv_1)