From 01b5d29136b37105c7e533bd3ec2299d31551627 Mon Sep 17 00:00:00 2001
From: bg <daniel.otte@rub.de>
Date: Sat, 15 Feb 2014 01:23:43 +0100
Subject: [PATCH] fixing problem with shifting 0

---
 bigint/bigint.c           | 32 ++++++++++++++++++--------------
 bigint/bigint.h           |  4 ++--
 mkfiles/rsaes_pkcs1v15.mk |  2 +-
 rsa/rsa_basic.c           |  3 ++-
 rsa/rsa_basic.h           |  1 -
 5 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/bigint/bigint.c b/bigint/bigint.c
index c5f799e..8524daa 100644
--- a/bigint/bigint.c
+++ b/bigint/bigint.c
@@ -97,9 +97,9 @@ bigint_length_t bigint_length_B(const bigint_t *a){
 
 /******************************************************************************/
 
-uint32_t bigint_get_first_set_bit(const bigint_t *a){
+int32_t bigint_get_first_set_bit(const bigint_t *a){
 	if(a->length_W == 0) {
-		return (uint32_t)(-1);
+		return -1;
 	}
 	return (a->length_W-1) * sizeof(bigint_word_t) * CHAR_BIT + GET_FBS(a);
 }
@@ -107,24 +107,24 @@ uint32_t bigint_get_first_set_bit(const bigint_t *a){
 
 /******************************************************************************/
 
-uint32_t bigint_get_last_set_bit(const bigint_t *a){
-	uint32_t r=0;
-	uint8_t b=0;
-	bigint_word_t x=1;
-	if(a->length_W==0){
-		return (uint32_t)(-1);
+int32_t bigint_get_last_set_bit(const bigint_t *a){
+	uint32_t r = 0;
+	uint8_t b = 0;
+	bigint_word_t x = 1;
+	if (a->length_W == 0) {
+		return -1;
 	}
-	while(a->wordv[r]==0 && r<a->length_W){
+	while (a->wordv[r] == 0 && r < a->length_W) {
 		++r;
 	}
-	if(a->wordv[r] == 0){
+	if (a->wordv[r] == 0) {
 		return (uint32_t)(-1);
 	}
-	while((x&a->wordv[r])==0){
+	while ((x&a->wordv[r])==0) {
 		++b;
 		x <<= 1;
 	}
-	return r*BIGINT_WORD_SIZE+b;
+	return r * BIGINT_WORD_SIZE + b;
 }
 
 /******************************************************************************/
@@ -374,7 +374,7 @@ void bigint_shiftleft(bigint_t *a, bigint_length_t shift){
 	bigint_word_t *p;
 	bigint_wordplus_t t = 0;
 
-	if (shift == 0) {
+	if (a->length_W == 0 || shift == 0) {
 		return;
 	}
 	byteshift = shift / 8;
@@ -416,6 +416,10 @@ void bigint_shiftright(bigint_t *a, bigint_length_t shift){
 	byteshift = shift / 8;
 	bitshift = shift & 7;
 
+	if (a->length_W == 0) {
+	    return;
+	}
+
 	if(bigint_get_first_set_bit(a) < shift){ /* we would shift out more than we have */
 		bigint_set_zero(a);
 		return;
@@ -424,9 +428,9 @@ void bigint_shiftright(bigint_t *a, bigint_length_t shift){
 	if(byteshift){
 		memmove(a->wordv, (uint8_t*)a->wordv + byteshift, a->length_W * sizeof(bigint_word_t) - byteshift);
 		memset((uint8_t*)&a->wordv[a->length_W] - byteshift, 0, byteshift);
+	    a->length_W -= byteshift / sizeof(bigint_word_t);
 	}
 
-    a->length_W -= byteshift / sizeof(bigint_word_t);
 
     if(bitshift != 0 && a->length_W){
 	 /* shift to the right */
diff --git a/bigint/bigint.h b/bigint/bigint.h
index f909795..82e10f8 100644
--- a/bigint/bigint.h
+++ b/bigint/bigint.h
@@ -68,8 +68,8 @@ typedef struct{
 /******************************************************************************/
 
 void   bigint_adjust(bigint_t *a);
-uint32_t bigint_get_first_set_bit(const bigint_t *a);
-uint32_t bigint_get_last_set_bit(const bigint_t *a);
+int32_t bigint_get_first_set_bit(const bigint_t *a);
+int32_t bigint_get_last_set_bit(const bigint_t *a);
 bigint_length_t bigint_length_b(const bigint_t *a);
 bigint_length_t bigint_length_B(const bigint_t *a);
 void   bigint_copy(bigint_t *dest, const bigint_t *src);
diff --git a/mkfiles/rsaes_pkcs1v15.mk b/mkfiles/rsaes_pkcs1v15.mk
index 8d15289..b2c14fd 100644
--- a/mkfiles/rsaes_pkcs1v15.mk
+++ b/mkfiles/rsaes_pkcs1v15.mk
@@ -2,7 +2,7 @@
 ALGO_NAME := RSAES_PKCS1V15
 
 # comment out the following line for removement of RSA from the build process
-SIGNATURE += $(ALGO_NAME)
+PK_CIPHERS += $(ALGO_NAME)
 
 $(ALGO_NAME)_DIR      := rsa/
 $(ALGO_NAME)_INCDIR   := memxor/ bigint/ noekeon/
diff --git a/rsa/rsa_basic.c b/rsa/rsa_basic.c
index 3d6581f..a7c3219 100644
--- a/rsa/rsa_basic.c
+++ b/rsa/rsa_basic.c
@@ -28,6 +28,7 @@
 
 #if DEBUG
 #include "cli.h"
+#include <stdio.h>
 #endif
 
 void rsa_enc(bigint_t *data, const rsa_publickey_t *key){
@@ -101,7 +102,7 @@ uint8_t rsa_dec_crt_mono(bigint_t *data, const rsa_privatekey_t *key){
 	while(BIGINT_NEG_MASK & m1.info){
 #if DEBUG
 	cli_putstr_P(PSTR("\r\nDBG: adding "));
-	bigint_print_hex(key->components[0]);
+	bigint_print_hex(&key->components[0]);
 	cli_putstr_P(PSTR("\r\nDBG: to "));
 	bigint_print_hex(&m1);
 #endif
diff --git a/rsa/rsa_basic.h b/rsa/rsa_basic.h
index 200c0fb..ccce4b0 100644
--- a/rsa/rsa_basic.h
+++ b/rsa/rsa_basic.h
@@ -33,7 +33,6 @@ typedef struct {
 	bigint_t *components;
 } rsa_privatekey_t;
 
-
 typedef struct {
 	rsa_privatekey_t priv;
 	rsa_publickey_t  pub;
-- 
2.39.5