now with rsassa-pkcs1v15 (old rsa signatures) + many new things

[arm-crypto-lib.git] / bigint / bigint.c

diff --git a/bigint/bigint.c b/bigint/bigint.c
index f0d7d6e6394e2ac8d889206d272b0bd86109e846..58661792f8fa856d8b1e657b2746c9135925386e 100644 (file)
--- a/bigint/bigint.c
+++ b/bigint/bigint.c
@@ -53,9 +53,9 @@
 #define SET_NEG(a)   (a)->info |= BIGINT_NEG_MASK
 #define SET_POS(a)   (a)->info &= ~BIGINT_NEG_MASK
 #define XCHG(a,b)    do{(a)^=(b); (b)^=(a); (a)^=(b);}while(0)
-#define XCHG_PTR(a,b)    do{ a = (void*)(((bigint_ptr_int_t)(a)) ^ ((bigint_ptr_int_t)(b))); \
-                                b = (void*)(((bigint_ptr_int_t)(a)) ^ ((bigint_ptr_int_t)(b))); \
-                                a = (void*)(((bigint_ptr_int_t)(a)) ^ ((bigint_ptr_int_t)(b)));}while(0)
+#define XCHG_PTR(a,b)    do{ a = (void*)(((intptr_t)(a)) ^ ((intptr_t)(b))); \
+                                b = (void*)(((intptr_t)(a)) ^ ((intptr_t)(b))); \
+                                a = (void*)(((intptr_t)(a)) ^ ((intptr_t)(b)));}while(0)
 
 #define GET_SIGN(a) ((a)->info&BIGINT_NEG_MASK)
 
@@ -80,7 +80,7 @@ void bigint_adjust(bigint_t* a){
 
 /******************************************************************************/
 
-uint16_t bigint_length_b(bigint_t* a){
+uint16_t bigint_length_b(const bigint_t* a){
        if(!a->length_B || a->length_B==0){
                return 0;
        }
@@ -89,13 +89,13 @@ uint16_t bigint_length_b(bigint_t* a){
 
 /******************************************************************************/
 
-uint16_t bigint_length_B(bigint_t* a){
+uint16_t bigint_length_B(const bigint_t* a){
        return a->length_B * sizeof(bigint_word_t);
 }
 
 /******************************************************************************/
 
-uint32_t bigint_get_first_set_bit(bigint_t* a){
+uint32_t bigint_get_first_set_bit(const bigint_t* a){
        if(a->length_B==0){
                return (uint32_t)(-1);
        }
@@ -105,7 +105,7 @@ uint32_t bigint_get_first_set_bit(bigint_t* a){
 
 /******************************************************************************/
 
-uint32_t bigint_get_last_set_bit(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;
@@ -403,7 +403,7 @@ int8_t bigint_cmp_s(const bigint_t* a, const bigint_t* b){
 /******************************************************************************/
 
 void bigint_shiftleft(bigint_t* a, uint16_t shift){
-       uint16_t byteshift, word_alloc;
+       uint16_t byteshift, word_alloc, words_to_shift;
        int16_t i;
        uint8_t bitshift;
        bigint_word_t *p;
@@ -417,14 +417,15 @@ void bigint_shiftleft(bigint_t* a, uint16_t shift){
                a->wordv[a->length_B+i] = 0;
        }
        if(byteshift){
-               memmove(((uint8_t*)a->wordv)+byteshift, a->wordv, a->length_B*sizeof(bigint_word_t));
+               memmove(((uint8_t*)a->wordv) + byteshift, a->wordv, a->length_B * sizeof(bigint_word_t));
                memset(a->wordv, 0, byteshift);
        }
-       p = (bigint_word_t*)(((uint8_t*)a->wordv)+byteshift);
-       word_alloc = a->length_B+(byteshift+sizeof(bigint_word_t)-1)/sizeof(bigint_word_t)+1;
+       p = a->wordv + byteshift / sizeof(bigint_word_t);
+       words_to_shift = a->length_B + (byteshift % sizeof(bigint_word_t)?1:0);
+       word_alloc = a->length_B + (byteshift + sizeof(bigint_word_t) - 1) / sizeof(bigint_word_t) + 1;
        a->wordv[word_alloc-1]=0;
        if(bitshift!=0){
-               for(i=0; i<a->length_B; ++i){
+               for(i=0; i < words_to_shift; ++i){
                        t |= ((bigint_wordplus_t)p[i])<<bitshift;
                        p[i] = (bigint_word_t)t;
                        t >>= BIGINT_WORD_SIZE;
@@ -444,30 +445,29 @@ void bigint_shiftright(bigint_t* a, uint16_t shift){
        bigint_wordplus_t t=0;
        byteshift = shift/8;
        bitshift = shift&7;
-       if(byteshift >= a->length_B*sizeof(bigint_word_t)){ /* we would shift out more than we have */
+       if(byteshift >= a->length_B * sizeof(bigint_word_t)){ /* we would shift out more than we have */
                bigint_set_zero(a);
                return;
        }
-       if(byteshift == a->length_B*sizeof(bigint_word_t)-1 && bitshift>GET_FBS(a)){
+       if(byteshift == a->length_B * sizeof(bigint_word_t) - 1 && bitshift > GET_FBS(a)){
                bigint_set_zero(a);
                return;
        }
        if(byteshift){
-               memmove(a->wordv, (uint8_t*)a->wordv+byteshift, a->length_B-byteshift);
-               memset((uint8_t*)a->wordv+a->length_B-byteshift, 0,  byteshift);
+               memmove(a->wordv, (uint8_t*)a->wordv + byteshift, a->length_B * sizeof(bigint_word_t) - byteshift);
+               memset((uint8_t*)a->wordv + a->length_B * sizeof(bigint_word_t) - byteshift, 0,  byteshift);
        }
        byteshift /= sizeof(bigint_word_t);
-       if(bitshift!=0){
+    a->length_B -= (byteshift  + sizeof(bigint_word_t) - 1) / sizeof(bigint_word_t);
+       if(bitshift != 0 && a->length_B){
         /* shift to the right */
-               for(i=a->length_B-byteshift-1; i>0; --i){
-                       t |= ((bigint_wordplus_t)(a->wordv[i]))<<(BIGINT_WORD_SIZE-bitshift);
-                       a->wordv[i] = (bigint_word_t)(t>>BIGINT_WORD_SIZE);
+               i = a->length_B - 1;
+               do{
+                       t |= ((bigint_wordplus_t)(a->wordv[i])) << (BIGINT_WORD_SIZE - bitshift);
+                       a->wordv[i] = (bigint_word_t)(t >> BIGINT_WORD_SIZE);
                        t <<= BIGINT_WORD_SIZE;
-               }
-               t |= ((bigint_wordplus_t)(a->wordv[0]))<<(BIGINT_WORD_SIZE-bitshift);
-               a->wordv[0] = (bigint_word_t)(t>>BIGINT_WORD_SIZE);
+               }while(i--);
        }
-    a->length_B -= ((shift/8)+sizeof(bigint_word_t)-1)/sizeof(bigint_word_t);
        bigint_adjust(a);
 }
 
@@ -792,12 +792,12 @@ void bigint_expmod_u(bigint_t* dest, const bigint_t* a, const bigint_t* exp, con
                        if(flag){
                                bigint_square(&res, &res);
                                bigint_reduce(&res, r);
-                               if(t & (1<<(BIGINT_WORD_SIZE-1))){
+                               if(t & (1 << (BIGINT_WORD_SIZE - 1))){
                                        bigint_mul_u(&res, &res, &base);
                                        bigint_reduce(&res, r);
                                }
                        }
-                       t<<=1;
+                       t <<= 1;
                }
        }