common: add PBKDF2-HMAC-SHA512 helper

Author: Chapoly1305

src/common/crypto.h

@@ -35,6 +35,9 @@ int decrypt_rfbdes(void *out, int *out_len, const unsigned char key[8], const vo
 /* Encrypts 'in' with the the 16-byte key in 'key' using AES-128-ECB and writes the result to 'out'. */
 int encrypt_aes128ecb(void *out, int *out_len, const unsigned char key[16], const void *in, const size_t in_len);
 
+/* Derives key material with PBKDF2-HMAC-SHA512. */
+int pbkdf2_hmac_sha512(const uint8_t *password, size_t password_len, const uint8_t *salt, size_t salt_len, uint32_t rounds, uint8_t *out, size_t out_len);
+
 /*
    Generates a Diffie-Hellman public-private keypair using the generator value 'gen' and prime modulo
    'prime', writing the result to 'pub_out' and 'priv_out', which must be 'keylen' in size.

src/common/crypto_included.c

@@ -90,6 +90,18 @@ int encrypt_aes128ecb(void *out, int *out_len, const unsigned char key[16], cons
     return 0;
 }
 
+int pbkdf2_hmac_sha512(const uint8_t *password, size_t password_len, const uint8_t *salt, size_t salt_len, uint32_t rounds, uint8_t *out, size_t out_len)
+{
+    (void)password;
+    (void)password_len;
+    (void)salt;
+    (void)salt_len;
+    (void)rounds;
+    (void)out;
+    (void)out_len;
+    return 0;
+}
+
 int dh_generate_keypair(uint8_t *priv_out, uint8_t *pub_out, const uint8_t *gen, const size_t gen_len, const uint8_t *prime, const size_t keylen)
 {
     return 0;

src/common/crypto_libgcrypt.c

@@ -220,6 +220,20 @@ int encrypt_aes128ecb(void *out, int *out_len, const unsigned char key[16], cons
     return result;
 }
 
+int pbkdf2_hmac_sha512(const uint8_t *password, size_t password_len,
+		       const uint8_t *salt, size_t salt_len, uint32_t rounds,
+		       uint8_t *out, size_t out_len)
+{
+    gcry_error_t error;
+
+    if (!password || !salt || !out || out_len == 0)
+	return 0;
+
+    error = gcry_kdf_derive(password, password_len, GCRY_KDF_PBKDF2, GCRY_MD_SHA512,
+			    salt, salt_len, rounds ? rounds : 1, out_len, out);
+    return gcry_err_code(error) == GPG_ERR_NO_ERROR;
+}
+
 int dh_generate_keypair(uint8_t *priv_out, uint8_t *pub_out, const uint8_t *gen, const size_t gen_len, const uint8_t *prime, const size_t keylen)
 {
     int result = 0;

src/common/crypto_openssl.c

@@ -199,6 +199,17 @@ int encrypt_aes128ecb(void *out, int *out_len, const unsigned char key[16], cons
     return result;
 }
 
+int pbkdf2_hmac_sha512(const uint8_t *password, size_t password_len,
+		       const uint8_t *salt, size_t salt_len, uint32_t rounds,
+		       uint8_t *out, size_t out_len)
+{
+    if (!password || !salt || !out || out_len == 0)
+	return 0;
+    return PKCS5_PBKDF2_HMAC((const char *)password, (int)password_len, salt,
+			     (int)salt_len, rounds ? (int)rounds : 1,
+			     EVP_sha512(), (int)out_len, out) == 1;
+}
+
 static void pad_leading_zeros(uint8_t *out, const size_t current_len, const size_t expected_len) {
     if (current_len >= expected_len || expected_len < 1)
         return;