Handle value_len == 0

Yubico · Mar 21, 2024 · 108c11a · 108c11a
1 parent 89006ae
commit 108c11a
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/pkcs11/util_pkcs11.c b/pkcs11/util_pkcs11.c
@@ -5331,7 +5331,7 @@ CK_RV ecdh_kdf(ecdh_session_key *shared_secret, uint8_t *fixed_info, size_t fixe
     uint8_t res[ECDH_KEY_BUF_SIZE] = {0};
     size_t res_len = 0;
 
-    while (res_len < value_len) {
+    do {
       increment_ctr(ctr, sizeof(ctr));
       hash_init(hash);
       hash_update(hash, ctr, sizeof(ctr));
@@ -5340,6 +5340,10 @@ CK_RV ecdh_kdf(ecdh_session_key *shared_secret, uint8_t *fixed_info, size_t fixe
       size_t len = sizeof(res) - res_len;
       hash_final(hash, res + res_len, &len);
       res_len += len;
+    } while(res_len < value_len);
+
+    if(value_len == 0) {
+      value_len = res_len;
     }
 
     memcpy(shared_secret->ecdh_key, res, value_len);