Some 'const's for BNs.

crypto/bn/bn.h

@@ -356,7 +356,7 @@ int	BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, const BIGNUM *d,
 	       BN_CTX *ctx);
 int	BN_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_CTX *ctx);
 int	BN_sqr(BIGNUM *r, BIGNUM *a,BN_CTX *ctx);
-BN_ULONG BN_mod_word(BIGNUM *a, BN_ULONG w);
+BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);
 BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w);
 int	BN_mul_word(BIGNUM *a, BN_ULONG w);
 int	BN_add_word(BIGNUM *a, BN_ULONG w);

crypto/bn/bn_prime.c

@@ -121,8 +121,8 @@
  */
 #include "bn_prime.h"
 
-static int witness(BIGNUM *w, BIGNUM *a, BIGNUM *a1, BIGNUM *a1_odd, int k,
-	BN_CTX *ctx, BN_MONT_CTX *mont);
+static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
+	const BIGNUM *a1_odd, int k, BN_CTX *ctx, BN_MONT_CTX *mont);
 static int probable_prime(BIGNUM *rnd, int bits);
 static int probable_prime_dh(BIGNUM *rnd, int bits,
 	BIGNUM *add, BIGNUM *rem, BN_CTX *ctx);
@@ -223,7 +223,7 @@ int BN_is_prime_fasttest(const BIGNUM *a, int checks,
 	BN_CTX *ctx = NULL;
 	BIGNUM *A1, *A1_odd, *check; /* taken from ctx */
 	BN_MONT_CTX *mont = NULL;
-	BIGNUM *A;
+	const BIGNUM *A;
 
 	if (checks == BN_prime_checks)
 		checks = BN_prime_checks_for_size(BN_num_bits(a));
@@ -247,9 +247,10 @@ int BN_is_prime_fasttest(const BIGNUM *a, int checks,
 	/* A := abs(a) */
 	if (a->neg)
 		{
-		A = &(ctx->bn[ctx->tos++]);
-		BN_copy(A, a);
-		A->neg = 0;
+		BIGNUM *t = &(ctx->bn[ctx->tos++]);
+		BN_copy(t, a);
+		t->neg = 0;
+		A = t;
 		}
 	else
 		A = a;
@@ -318,8 +319,8 @@ err:
 	return(ret);
 	}
 
-static int witness(BIGNUM *w, BIGNUM *a, BIGNUM *a1, BIGNUM *a1_odd, int k,
-	BN_CTX *ctx, BN_MONT_CTX *mont)
+static int witness(BIGNUM *w, const BIGNUM *a, const BIGNUM *a1,
+	const BIGNUM *a1_odd, int k, BN_CTX *ctx, BN_MONT_CTX *mont)
 	{
 	if (!BN_mod_exp_mont(w, w, a1_odd, a, ctx, mont)) /* w := w^a1_odd mod a */
 		return -1;

crypto/bn/bn_word.c

@@ -60,7 +60,7 @@
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
-BN_ULONG BN_mod_word(BIGNUM *a, BN_ULONG w)
+BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w)
 	{
 #ifndef BN_LLONG
 	BN_ULONG ret=0;

doc/crypto/BN_add_word.pod

@@ -17,7 +17,7 @@ functions on BIGNUMs with integers
 
  BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w);
 
- BN_ULONG BN_mod_word(BIGNUM *a, BN_ULONG w);
+ BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);
 
 =head1 DESCRIPTION
 

doc/crypto/bn.pod

@@ -43,7 +43,7 @@ bn - Multiprecision integer arithmetics
  int BN_sub_word(BIGNUM *a, BN_ULONG w);
  int BN_mul_word(BIGNUM *a, BN_ULONG w);
  BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w);
- BN_ULONG BN_mod_word(BIGNUM *a, BN_ULONG w);
+ BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);
 
  int BN_cmp(BIGNUM *a, BIGNUM *b);
  int BN_ucmp(BIGNUM *a, BIGNUM *b);
@@ -63,7 +63,7 @@ bn - Multiprecision integer arithmetics
 
  BIGNUM *BN_generate_prime(BIGNUM *ret,int bits,int safe,BIGNUM *add,
          BIGNUM *rem,void (*callback)(int,int,void *),void *cb_arg);
- int BN_is_prime(BIGNUM *p,int nchecks,void (*callback)(int,int,void *),
+ int BN_is_prime(const BIGNUM *p,int nchecks,void (*callback)(int,int,void *),
          BN_CTX *ctx,void *cb_arg);
 
  int BN_set_bit(BIGNUM *a, int n);