From 7f67e79ddcacf9c0f98ae9749bc1c61d75570ce1 Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@anytun.org>
Date: Sun, 4 Jan 2009 14:21:20 +0000
Subject: get rid of some mallocs and mpz_inits at cipher

---
 src/cipher.c | 124 ++++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 81 insertions(+), 43 deletions(-)

(limited to 'src/cipher.c')

diff --git a/src/cipher.c b/src/cipher.c
index 07c9f32..ff9e4e9 100644
--- a/src/cipher.c
+++ b/src/cipher.c
@@ -77,9 +77,7 @@ int cipher_init(cipher_t* c, const char* type)
     return -1;
   }
 
-#ifndef NO_CRYPT
-  c->handle_ = 0;
-#endif
+  c->params_ = NULL;
 
   c->key_.buf_ = NULL;
   c->key_.length_ = 0;
@@ -209,6 +207,29 @@ int cipher_aesctr_init(cipher_t* c)
   if(!c->salt_.buf_)
     return -2;
 
+  if(c->params_)
+    free(c->params_);
+  c->params_ = malloc(sizeof(cipher_aesctr_param_t));
+  if(!c->params_)
+    return -2;
+
+  cipher_aesctr_param_t* params = c->params_;
+
+#ifndef NO_LIBGMP
+  mpz_init2(params->mp_ctr, 128);
+  mpz_init2(params->mp_sid_mux, 128);
+  mpz_init2(params->mp_seq, 128);
+#endif
+
+  params->ctr_.length_ = 16;
+  params->ctr_.buf_ = malloc(params->ctr_.length_);
+  if(!params->ctr_.buf_) {
+    free(c->params_);
+    c->params_ = NULL;
+    return -2;
+  }
+
+
   int algo;
   switch(c->key_length_) {
   case 128: algo = GCRY_CIPHER_AES128; break;
@@ -220,7 +241,7 @@ int cipher_aesctr_init(cipher_t* c)
   }
   }
 
-  gcry_error_t err = gcry_cipher_open(&c->handle_, algo, GCRY_CIPHER_MODE_CTR, 0);
+  gcry_error_t err = gcry_cipher_open(&params->handle_, algo, GCRY_CIPHER_MODE_CTR, 0);
   if(err) {
     log_printf(ERR, "failed to open cipher: %s/%s", gcry_strerror(err), gcry_strsource(err));
     return -1;
@@ -234,22 +255,35 @@ void cipher_aesctr_close(cipher_t* c)
   if(!c)
     return;
 
-  if(c->handle_)
-    gcry_cipher_close(c->handle_);
+  if(c->params_) {
+    cipher_aesctr_param_t* params = c->params_;
+#ifndef NO_LIBGMP
+    mpz_clear(params->mp_ctr);
+    mpz_clear(params->mp_sid_mux);
+    mpz_clear(params->mp_seq);
+#endif
+    if(params->ctr_.buf_)
+      free(params->ctr_.buf_);
+
+    if(params->handle_)
+      gcry_cipher_close(params->handle_);
+
+    free(c->params_);
+  }
 }
 
-buffer_t cipher_aesctr_calc_ctr(cipher_t* c, key_derivation_t* kd, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
+int cipher_aesctr_calc_ctr(cipher_t* c, key_derivation_t* kd, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
 {
-  buffer_t result;
-  result.buf_ = NULL;
-  result.length_ = 0;
-
-  if(!c)
-    return result;
+  if(!c || !c->params_)
+    return -1;
   
+  cipher_aesctr_param_t* params = c->params_;
+  if(!params->ctr_.buf_)
+    return -1;
+
   int ret = key_derivation_generate(kd, LABEL_SATP_SALT, seq_nr, c->salt_.buf_, c->salt_.length_);
   if(ret < 0)
-    return result;
+    return ret;
 
   int faked_msb = 0;
   if(!c->salt_.buf_[0]) {
@@ -258,45 +292,50 @@ buffer_t cipher_aesctr_calc_ctr(cipher_t* c, key_derivation_t* kd, seq_nr_t seq_
   }
 
 #ifndef NO_LIBGMP
-  mpz_t ctr, sid_mux, seq;
-  mpz_init2(ctr, 128);
-  mpz_init2(sid_mux, 128);
-  mpz_init2(seq, 128);
-  
-  mpz_import(ctr, c->salt_.length_, 1, 1, 0, 0, c->salt_.buf_);
+  mpz_import(params->mp_ctr, c->salt_.length_, 1, 1, 0, 0, c->salt_.buf_);
 
-  mpz_set_ui(sid_mux, mux);
-  mpz_mul_2exp(sid_mux, sid_mux, (sizeof(sender_id) * 8));
-  mpz_add_ui(sid_mux, sid_mux, sender_id);
-  mpz_mul_2exp(sid_mux, sid_mux, 48);
+  mpz_set_ui(params->mp_sid_mux, mux);
+  mpz_mul_2exp(params->mp_sid_mux, params->mp_sid_mux, (sizeof(sender_id) * 8));
+  mpz_add_ui(params->mp_sid_mux, params->mp_sid_mux, sender_id);
+  mpz_mul_2exp(params->mp_sid_mux, params->mp_sid_mux, 48);
 
-  mpz_set_ui(seq, seq_nr);
+  mpz_set_ui(params->mp_seq, seq_nr);
 
-  mpz_xor(ctr, ctr, sid_mux);
-  mpz_xor(ctr, ctr, seq);
+  mpz_xor(params->mp_ctr, params->mp_ctr, params->mp_sid_mux);
+  mpz_xor(params->mp_ctr, params->mp_ctr, params->mp_seq);
 
-  mpz_mul_2exp(ctr, ctr, 16);
+  mpz_mul_2exp(params->mp_ctr, params->mp_ctr, 16);
 
-  result.buf_ = mpz_export(NULL, (size_t*)&result.length_, 1, 1, 0, 0, ctr);
-  mpz_clear(ctr);
-  mpz_clear(sid_mux);
-  mpz_clear(seq);
+  int out_size = (mpz_sizeinbase(params->mp_ctr, 2) + 7) / 8;
+  if(out_size > params->ctr_.length_) {
+    log_printf(ERR, "computed cipher ctr is too big ?!?");
+    return -1;
+  }
+  mpz_export(params->ctr_.buf_, NULL, 1, 1, 0, 0, params->mp_ctr);
 #endif
 
 #ifndef ANYTUN_02_COMPAT
   if(faked_msb) {
     c->salt_.buf_[0] = 0;
-    result.buf_[0] = 0;
+    params->ctr_.buf_[0] = 0;
   }
 #endif
 
-  return result;
+  return 0;
 }
 
 int32_t cipher_aesctr_crypt(cipher_t* c, key_derivation_t* kd, u_int8_t* in, u_int32_t ilen, u_int8_t* out, u_int32_t olen, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
 {
-  if(!c)
+  if(!c || !c->params_) {
+    log_printf(ERR, "cipher not initialized");
+    return -1;
+  }
+
+  cipher_aesctr_param_t* params = c->params_;
+  if(!params->ctr_.buf_) {
+    log_printf(ERR, "cipher not initialized");
     return -1;
+  }
 
   if(!kd) {
     log_printf(ERR, "no key derivation supplied");
@@ -309,34 +348,33 @@ int32_t cipher_aesctr_crypt(cipher_t* c, key_derivation_t* kd, u_int8_t* in, u_i
   
   gcry_error_t err;
   if(ret) { // a new key got generated
-    err = gcry_cipher_setkey(c->handle_, c->key_.buf_, c->key_.length_);
+    err = gcry_cipher_setkey(params->handle_, c->key_.buf_, c->key_.length_);
     if(err) {
       log_printf(ERR, "failed to set cipher key: %s/%s", gcry_strerror(err), gcry_strsource(err));
       return -1;
     }
   } // no new key got generated
   else {
-    err = gcry_cipher_reset(c->handle_);
+    err = gcry_cipher_reset(params->handle_);
     if(err) {
       log_printf(ERR, "failed to reset cipher: %s/%s", gcry_strerror(err), gcry_strsource(err));
       return -1;
     }
   }
 
-  buffer_t ctr = cipher_aesctr_calc_ctr(c, kd, seq_nr, sender_id, mux);
-  if(!ctr.buf_) {
+  ret = cipher_aesctr_calc_ctr(c, kd, seq_nr, sender_id, mux);
+  if(ret < 0) {
     log_printf(ERR, "failed to calculate cipher CTR");
-    return -1;
+    return ret;
   }
-  err = gcry_cipher_setctr(c->handle_, ctr.buf_, ctr.length_);
-  free(ctr.buf_);
+  err = gcry_cipher_setctr(params->handle_, params->ctr_.buf_, params->ctr_.length_);
 
   if(err) {
     log_printf(ERR, "failed to set cipher CTR: %s/%s", gcry_strerror(err), gcry_strsource(err));
     return -1;
   }
 
-  err = gcry_cipher_encrypt(c->handle_, out, olen, in, ilen);
+  err = gcry_cipher_encrypt(params->handle_, out, olen, in, ilen);
   if(err) {
     log_printf(ERR, "failed to de/encrypt packet: %s/%s", gcry_strerror(err), gcry_strsource(err));
     return -1;
-- 
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