Merge remote-tracking branch 'kuon/patch-2'

c_src/enacl_nif.c

@@ -11,6 +11,7 @@
 #include "kx.h"
 #include "public.h"
 #include "pwhash.h"
+#include "kdf.h"
 #include "randombytes.h"
 #include "secret.h"
 #include "secretstream.h"
@@ -294,6 +295,11 @@ static ErlNifFunc nif_funcs[] = {
     erl_nif_dirty_job_cpu_bound_macro("crypto_pwhash_str_verify", 2,
                                       enacl_crypto_pwhash_str_verify),
 
+    {"crypto_kdf_KEYBYTES", 0, enacl_crypto_kdf_KEYBYTES},
+    {"crypto_kdf_CONTEXTBYTES", 0, enacl_crypto_kdf_CONTEXTBYTES},
+    erl_nif_dirty_job_cpu_bound_macro("crypto_kdf_derive_from_key", 3,
+                                      enacl_crypto_kdf_derive_from_key),
+
     erl_nif_dirty_job_cpu_bound_macro("crypto_curve25519_scalarmult", 2,
                                       enacl_crypto_curve25519_scalarmult),
     erl_nif_dirty_job_cpu_bound_macro("crypto_curve25519_scalarmult_base", 1,

c_src/kdf.c

@@ -0,0 +1,59 @@
+#include <sodium.h>
+
+#include <erl_nif.h>
+
+#include "enacl.h"
+#include "kdf.h"
+
+
+ERL_NIF_TERM enacl_crypto_kdf_KEYBYTES(ErlNifEnv *env, int argc,
+                                       ERL_NIF_TERM const argv[]) {
+  return enif_make_int64(env, crypto_kdf_KEYBYTES);
+}
+
+ERL_NIF_TERM enacl_crypto_kdf_CONTEXTBYTES(ErlNifEnv *env, int argc,
+                                       ERL_NIF_TERM const argv[]) {
+  return enif_make_int64(env, crypto_kdf_CONTEXTBYTES);
+}
+
+
+ERL_NIF_TERM enacl_crypto_kdf_derive_from_key(ErlNifEnv *env, int argc,
+                                              ERL_NIF_TERM const argv[]) {
+  ErlNifBinary m, c, r;
+  uint64_t id;
+
+  // Validate the arguments
+  if ((argc != 3) ||
+      (!enif_inspect_iolist_as_binary(env, argv[0], &m)) ||
+      (!enif_inspect_binary(env, argv[1], &c)) ||
+      (!enif_get_uint64(env, argv[2], &id))) {
+    return enif_make_badarg(env);
+  }
+
+  // Check Master Key length
+  if (m.size != crypto_kdf_KEYBYTES) {
+    return enif_make_badarg(env);
+  }
+
+  // Check Context Key length
+  if (c.size != crypto_kdf_CONTEXTBYTES) {
+    return enif_make_badarg(env);
+  }
+
+  // Allocate memory for return binary
+  if (!enif_alloc_binary(crypto_kdf_KEYBYTES, &r)) {
+    return enacl_internal_error(env);
+  }
+
+  if (crypto_kdf_derive_from_key(r.data, r.size,
+                    id,
+                    (const char *)c.data,
+                    m.data) != 0) {
+    /* out of memory */
+    enif_release_binary(&r);
+    return enacl_internal_error(env);
+  }
+
+  return enif_make_binary(env, &r);
+}
+

c_src/kdf.h

@@ -0,0 +1,15 @@
+#ifndef ENACL_KDF_H
+#define ENACL_KDF_H
+
+#include <erl_nif.h>
+
+ERL_NIF_TERM enacl_crypto_kdf_KEYBYTES(ErlNifEnv *env, int argc,
+                                       ERL_NIF_TERM const argv[]);
+
+ERL_NIF_TERM enacl_crypto_kdf_CONTEXTBYTES(ErlNifEnv *env, int argc,
+                                           ERL_NIF_TERM const argv[]);
+
+ERL_NIF_TERM enacl_crypto_kdf_derive_from_key(ErlNifEnv *env, int argc,
+                                              ERL_NIF_TERM const argv[]);
+
+#endif