From 4426f95b08521cb2356a54ece0e4c803c8cab309 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@anytun.org>
Date: Sun, 4 Jan 2009 22:13:06 +0000
Subject: added libgmp free ctr calc implementation to key derivation

---
 src/Makefile         |  2 +-
 src/key_derivation.c | 24 ++++++++++++++++++------
 src/key_derivation.h | 41 ++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 59 insertions(+), 8 deletions(-)

diff --git a/src/Makefile b/src/Makefile
index 45ae277..30aebf9 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -34,7 +34,7 @@
 
 TARGET=$(shell uname -s)
 CC = gcc
-CCFLAGS = -g -O2 -DANYTUN_02_COMPAT #-DNO_LIBGMP -DNO_CRYPT
+CCFLAGS = -g -O2 # -DNO_LIBGMP # -DANYTUN_02_COMPAT #-DNO_CRYPT
 LD = gcc
 LDFLAGS = -g -Wall -O2 -lgcrypt -lgpg-error -lgmp
 
diff --git a/src/key_derivation.c b/src/key_derivation.c
index aec90a1..eaf80e5 100644
--- a/src/key_derivation.c
+++ b/src/key_derivation.c
@@ -188,17 +188,20 @@ int key_derivation_aesctr_init(key_derivation_t* kd)
   key_derivation_aesctr_param_t* params = kd->params_;
 
 #ifndef NO_LIBGMP
-  mpz_init2(params->mp_ctr, 128);
-  mpz_init2(params->mp_key_id, 128);
-#endif
+  mpz_init2(params->mp_ctr, KD_AES_CTR_LENGTH * 8);
+  mpz_init2(params->mp_key_id, KD_AES_CTR_LENGTH * 8);
 
-  params->ctr_.length_ = 16;
+  params->ctr_.length_ = KD_AES_CTR_LENGTH;
   params->ctr_.buf_ = malloc(params->ctr_.length_);
   if(!params->ctr_.buf_) {
     free(kd->params_);
     kd->params_ = NULL;
     return -2;
   }
+#else
+  params->ctr_.length_ = KD_AES_CTR_LENGTH;
+  params->ctr_.buf_ = params->ctr_.ctr_.buf_;
+#endif
 
   gcry_error_t err = gcry_cipher_open(&params->handle_, algo, GCRY_CIPHER_MODE_CTR, 0);
   if(err) {
@@ -225,9 +228,9 @@ void key_derivation_aesctr_close(key_derivation_t* kd)
 #ifndef NO_LIBGMP
     mpz_clear(params->mp_ctr);
     mpz_clear(params->mp_key_id);
-#endif
     if(params->ctr_.buf_)
       free(params->ctr_.buf_);
+#endif
 
     if(params->handle_)
       gcry_cipher_close(params->handle_);
@@ -273,7 +276,7 @@ int key_derivation_aesctr_calc_ctr(key_derivation_t* kd, seq_nr_t* r, satp_prf_l
   mpz_add_ui(params->mp_key_id, params->mp_key_id, *r);
 
   mpz_xor(params->mp_ctr, params->mp_ctr, params->mp_key_id);
-  mpz_mul_2exp(params->mp_ctr, params->mp_ctr, 16);
+  mpz_mul_2exp(params->mp_ctr, params->mp_ctr, KD_AES_CTR_ZERO_LENGTH * 8);
 
   int out_size = (mpz_sizeinbase(params->mp_ctr, 2) + 7) / 8;
   if(out_size > params->ctr_.length_) {
@@ -281,6 +284,15 @@ int key_derivation_aesctr_calc_ctr(key_derivation_t* kd, seq_nr_t* r, satp_prf_l
     return -1;
   }
   mpz_export(params->ctr_.buf_, NULL, 1, 1, 0, 0, params->mp_ctr);
+#else
+  if(kd->master_salt_.length_ != sizeof(params->ctr_.ctr_.salt_.buf_)) {
+    log_printf(ERR, "master salt has the wrong length");
+    return -1;
+  }
+  memcpy(params->ctr_.ctr_.salt_.buf_, kd->master_salt_.buf_, sizeof(params->ctr_.ctr_.salt_.buf_));
+  memset(params->ctr_.ctr_.salt_.zero_, 0, sizeof(params->ctr_.ctr_.salt_.zero_));
+  params->ctr_.ctr_.params_.label_ ^= label;
+  params->ctr_.ctr_.params_.r_ ^= SEQ_NR_T_HTON(*r);
 #endif
 
 #ifndef ANYTUN_02_COMPAT
diff --git a/src/key_derivation.h b/src/key_derivation.h
index 72037bf..1b8cd40 100644
--- a/src/key_derivation.h
+++ b/src/key_derivation.h
@@ -74,12 +74,51 @@ int key_derivation_generate(key_derivation_t* kd, satp_prf_label_t label, seq_nr
 
 int key_derivation_null_generate(u_int8_t* key, u_int32_t len);
 
+
+#define KD_AES_CTR_LENGTH 16
+#define KD_AES_CTR_ZERO_LENGTH 2
+#ifdef NO_LIBGMP
+union __attribute__ ((__packed__)) key_derivation_aesctr_ctr_buf_union {
+  u_int8_t buf_[KD_AES_CTR_LENGTH];
+  struct __attribute__ ((__packed__)) {
+    u_int8_t buf_[KD_AES_CTR_LENGTH - KD_AES_CTR_ZERO_LENGTH];
+    u_int8_t zero_[KD_AES_CTR_ZERO_LENGTH];
+  } salt_;
+#ifndef ANYTUN_02_COMPAT
+  struct __attribute__ ((__packed__)) {
+    u_int8_t fill_[KD_AES_CTR_LENGTH - sizeof(u_int8_t) - sizeof(seq_nr_t) - KD_AES_CTR_ZERO_LENGTH];
+    u_int8_t label_;
+    seq_nr_t r_;
+    u_int8_t zero_[KD_AES_CTR_ZERO_LENGTH];
+  } params_;
+#else
+  struct __attribute__ ((__packed__)) {
+    u_int8_t fill_[KD_AES_CTR_LENGTH - sizeof(u_int8_t) - 2 - sizeof(seq_nr_t) - KD_AES_CTR_ZERO_LENGTH];
+    u_int8_t label_;
+    u_int8_t r_fill_[2];
+    seq_nr_t r_;
+    u_int8_t zero_[KD_AES_CTR_ZERO_LENGTH];
+  } params_;
+#endif
+};
+typedef union key_derivation_aesctr_ctr_buf_union key_derivation_aesctr_ctr_buf_t;
+
+struct key_derivation_aesctr_ctr_struct {
+  u_int32_t length_;
+  u_int8_t* buf_;
+  key_derivation_aesctr_ctr_buf_t ctr_;
+};
+typedef struct key_derivation_aesctr_ctr_struct key_derivation_aesctr_ctr_t;
+#endif
+
 struct key_derivation_aesctr_param_struct {
   gcry_cipher_hd_t handle_;
-  buffer_t ctr_;
 #ifndef NO_LIBGMP
+  buffer_t ctr_;
   mpz_t mp_ctr;
   mpz_t mp_key_id;
+#else
+  key_derivation_aesctr_ctr_t ctr_;
 #endif
 };
 typedef struct key_derivation_aesctr_param_struct key_derivation_aesctr_param_t;
-- 
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