From 49b279e8d329a21cbc120186dd25852f302c02a3 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@anytun.org>
Date: Sat, 21 Jun 2014 19:46:49 +0000
Subject: implemented key derivation in nettle fixed key length for cipher

---
 src/cipher.c         |  2 +-
 src/key_derivation.c | 24 ++++++++++++++++--------
 src/key_derivation.h |  3 +--
 3 files changed, 18 insertions(+), 11 deletions(-)

(limited to 'src')

diff --git a/src/cipher.c b/src/cipher.c
index bf9ac25..9afd84a 100644
--- a/src/cipher.c
+++ b/src/cipher.c
@@ -303,7 +303,7 @@ int32_t cipher_aesctr_crypt(cipher_t* c, key_derivation_t* kd, key_derivation_di
     return -1;
   }
 #elif defined(USE_NETTLE)
-  aes_set_encrypt_key(&params->ctx_, c->key_length_, c->key_.buf_);
+  aes_set_encrypt_key(&params->ctx_, c->key_.length_, c->key_.buf_);
 #else  // USE_GCRYPT is the default
   gcry_error_t err = gcry_cipher_setkey(params->handle_, c->key_.buf_, c->key_.length_);
   if(err) {
diff --git a/src/key_derivation.c b/src/key_derivation.c
index 998c10b..75ce4a5 100644
--- a/src/key_derivation.c
+++ b/src/key_derivation.c
@@ -42,6 +42,7 @@
 #elif defined(USE_NETTLE)
 #include <nettle/sha1.h>
 #include <nettle/sha2.h>
+#include <nettle/ctr.h>
 #endif
 
 #include "log.h"
@@ -165,8 +166,10 @@ int key_derivation_generate_master_key(key_derivation_t* kd, const char* passphr
 #if defined(USE_SSL_CRYPTO)
   SHA256((const u_int8_t*)passphrase, strlen(passphrase), digest.buf_);
 #elif defined(USE_NETTLE)
-      // TODO: nettle
-
+  struct sha256_ctx ctx;
+  sha256_init(&ctx);
+  sha256_update(&ctx, strlen(passphrase), (const u_int8_t*)passphrase);
+  sha256_digest(&ctx, digest.length_, digest.buf_);
 #else  // USE_GCRYPT is the default
   gcry_md_hash_buffer(GCRY_MD_SHA256, digest.buf_, passphrase, strlen(passphrase));
 #endif
@@ -227,8 +230,10 @@ int key_derivation_generate_master_salt(key_derivation_t* kd, const char* passph
 #if defined(USE_SSL_CRYPTO)
   SHA1((const u_int8_t*)passphrase, strlen(passphrase), digest.buf_);
 #elif defined(USE_NETTLE)
-      // TODO: nettle
-
+  struct sha1_ctx ctx;
+  sha1_init(&ctx);
+  sha1_update(&ctx, strlen(passphrase), (const u_int8_t*)passphrase);
+  sha1_digest(&ctx, digest.length_, digest.buf_);
 #else  // USE_GCRYPT is the default
   gcry_md_hash_buffer(GCRY_MD_SHA1, digest.buf_, passphrase, strlen(passphrase));
 #endif
@@ -369,8 +374,7 @@ int key_derivation_aesctr_init(key_derivation_t* kd, const char* passphrase)
     return -1;
   }
 #elif defined(USE_NETTLE)
-      // TODO: nettle
-
+  aes_set_encrypt_key(&params->ctx_, kd->master_key_.length_, kd->master_key_.buf_);
 #else  // USE_GCRYPT is the default
   int algo;
   switch(kd->key_length_) {
@@ -458,8 +462,12 @@ int key_derivation_aesctr_generate(key_derivation_t* kd, key_derivation_dir_t di
   memset(key, 0, len);
   AES_ctr128_encrypt(key, key, len, &params->aes_key_, params->ctr_.buf_, params->ecount_buf_, &num);
 #elif defined(USE_NETTLE)
-      // TODO: nettle
-
+  if(KD_AESCTR_CTR_LENGTH != AES_BLOCK_SIZE) {
+    log_printf(ERROR, "failed to set cipher CTR: size doesn't fit");
+    return -1;
+  }
+  memset(key, 0, len);
+  ctr_crypt(&params->ctx_, (nettle_crypt_func *)(aes_encrypt), AES_BLOCK_SIZE, params->ctr_.buf_, len, key, key);
 #else  // USE_GCRYPT is the default
   gcry_error_t err = gcry_cipher_reset(params->handle_);
   if(err) {
diff --git a/src/key_derivation.h b/src/key_derivation.h
index 01c9a26..df97765 100644
--- a/src/key_derivation.h
+++ b/src/key_derivation.h
@@ -109,8 +109,7 @@ struct key_derivation_aesctr_param_struct {
   AES_KEY aes_key_;
   u_int8_t ecount_buf_[AES_BLOCK_SIZE];
 #elif defined(USE_NETTLE)
-      // TODO: nettle
-
+  struct aes_ctx ctx_;
 #else  // USE_GCRYPT is the default
   gcry_cipher_hd_t handle_;
 #endif
-- 
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