Commit e1064adf authored by Geoff Thorpe's avatar Geoff Thorpe
Browse files

Some changes for bn_gf2m.c: better error checking plus some minor 

optimizations.

Submitted by: Nils Larsch
parent d7559f16

crypto/bn/bn_gf2m.c

+48 −30
Original line number Diff line number Diff line
@@ -323,8 +323,12 @@ int BN_GF2m_mod_arr(BIGNUM *r, const BIGNUM *a, const unsigned int p[]) 
	int n, dN, d0, d1;

	BN_ULONG zz, *z;

	

	/* Since the algorithm does reduction in the r value, if a != r, copy the

	 * contents of a into r so we can do reduction in r. 

	if (!p[0])

		/* reduction mod 1 => return 0 */

		return BN_zero(r);



	/* Since the algorithm does reduction in the r value, if a != r, copy

	 * the contents of a into r so we can do reduction in r. 

	 */

	if (a != r)

		{
@@ -345,7 +349,7 @@ int BN_GF2m_mod_arr(BIGNUM *r, const BIGNUM *a, const unsigned int p[]) 
		if (z[j] == 0) { j--; continue; }

		z[j] = 0;



		for (k = 1; p[k] > 0; k++)

		for (k = 1; p[k] != 0; k++)

			{

			/* reducing component t^p[k] */

			n = p[0] - p[k];
@@ -375,7 +379,7 @@ int BN_GF2m_mod_arr(BIGNUM *r, const BIGNUM *a, const unsigned int p[]) 
		if (d0) z[dN] = (z[dN] << d1) >> d1; /* clear up the top d1 bits */

		z[0] ^= zz; /* reduction t^0 component */



		for (k = 1; p[k] > 0; k++)

		for (k = 1; p[k] != 0; k++)

			{

			BN_ULONG tmp_ulong;
@@ -408,7 +412,8 @@ int BN_GF2m_mod(BIGNUM *r, const BIGNUM *a, const BIGNUM *p) 
	const int max = BN_num_bits(p);

	unsigned int *arr=NULL, ret = 0;

	if ((arr = (unsigned int *)OPENSSL_malloc(sizeof(unsigned int) * max)) == NULL) goto err;

	if (BN_GF2m_poly2arr(p, arr, max) > max)

	ret = BN_GF2m_poly2arr(p, arr, max);

	if (!ret || ret > max)

		{

		BNerr(BN_F_BN_GF2M_MOD,BN_R_INVALID_LENGTH);

		goto err;
@@ -459,9 +464,9 @@ int BN_GF2m_mod_mul_arr(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const unsig 
		}



	bn_correct_top(s);

	BN_GF2m_mod_arr(r, s, p);

	bn_check_top(r);

	if (BN_GF2m_mod_arr(r, s, p))

		ret = 1;

	bn_check_top(r);



  err:

	BN_CTX_end(ctx);
@@ -481,7 +486,8 @@ int BN_GF2m_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *p 
	const int max = BN_num_bits(p);

	unsigned int *arr=NULL, ret = 0;

	if ((arr = (unsigned int *)OPENSSL_malloc(sizeof(unsigned int) * max)) == NULL) goto err;

	if (BN_GF2m_poly2arr(p, arr, max) > max)

	ret = BN_GF2m_poly2arr(p, arr, max);

	if (!ret || ret > max)

		{

		BNerr(BN_F_BN_GF2M_MOD_MUL,BN_R_INVALID_LENGTH);

		goto err;
@@ -531,7 +537,8 @@ int BN_GF2m_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) 
	const int max = BN_num_bits(p);

	unsigned int *arr=NULL, ret = 0;

	if ((arr = (unsigned int *)OPENSSL_malloc(sizeof(unsigned int) * max)) == NULL) goto err;

	if (BN_GF2m_poly2arr(p, arr, max) > max)

	ret = BN_GF2m_poly2arr(p, arr, max);

	if (!ret || ret > max)

		{

		BNerr(BN_F_BN_GF2M_MOD_SQR,BN_R_INVALID_LENGTH);

		goto err;
@@ -567,10 +574,6 @@ int BN_GF2m_mod_inv(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) 
	if (!BN_GF2m_mod(u, a, p)) goto err;

	if (!BN_copy(v, p)) goto err;



	u->neg = 0; /* Need to set u->neg = 0 because BN_is_one(u) checks

	             * the neg flag of the bignum.

	             */



	if (BN_is_zero(u)) goto err;



	while (1)
@@ -585,7 +588,7 @@ int BN_GF2m_mod_inv(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) 
			if (!BN_rshift1(b, b)) goto err;

			}



		if (BN_is_one(u)) break;

		if (BN_abs_is_word(u, 1)) break;



		if (BN_num_bits(u) < BN_num_bits(v))

			{
@@ -679,10 +682,6 @@ int BN_GF2m_mod_div(BIGNUM *r, const BIGNUM *y, const BIGNUM *x, const BIGNUM *p 
	if (!BN_copy(b, p)) goto err;

	if (!BN_zero(v)) goto err;

	

	a->neg = 0; /* Need to set a->neg = 0 because BN_is_one(a) checks

	             * the neg flag of the bignum.

	             */



	while (!BN_is_odd(a))

		{

		if (!BN_rshift1(a, a)) goto err;
@@ -703,7 +702,7 @@ int BN_GF2m_mod_div(BIGNUM *r, const BIGNUM *y, const BIGNUM *x, const BIGNUM *p 
				if (!BN_rshift1(v, v)) goto err;

				} while (!BN_is_odd(b));

			}

		else if (BN_is_one(a))

		else if (BN_abs_is_word(a, 1))

			break;

		else

			{
@@ -763,9 +762,10 @@ int BN_GF2m_mod_exp_arr(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const unsig 
	BIGNUM *u;

	

	if (BN_is_zero(b))

		{

		return(BN_one(r));

		}



	if (BN_abs_is_word(b, 1))

		return (BN_copy(r, a) != NULL);

	



	BN_CTX_start(ctx);
@@ -804,7 +804,8 @@ int BN_GF2m_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *p 
	const int max = BN_num_bits(p);

	unsigned int *arr=NULL, ret = 0;

	if ((arr = (unsigned int *)OPENSSL_malloc(sizeof(unsigned int) * max)) == NULL) goto err;

	if (BN_GF2m_poly2arr(p, arr, max) > max)

	ret = BN_GF2m_poly2arr(p, arr, max);

	if (!ret || ret > max)

		{

		BNerr(BN_F_BN_GF2M_MOD_EXP,BN_R_INVALID_LENGTH);

		goto err;
@@ -825,6 +826,10 @@ int BN_GF2m_mod_sqrt_arr(BIGNUM *r, const BIGNUM *a, const unsigned int p[], BN_ 
	int ret = 0;

	BIGNUM *u;



	if (!p[0])

		/* reduction mod 1 => return 0 */

		return BN_zero(r);

	

	BN_CTX_start(ctx);

	if ((u = BN_CTX_get(ctx)) == NULL) goto err;
@@ -850,7 +855,8 @@ int BN_GF2m_mod_sqrt(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) 
	const int max = BN_num_bits(p);

	unsigned int *arr=NULL, ret = 0;

	if ((arr = (unsigned int *)OPENSSL_malloc(sizeof(unsigned int) * max)) == NULL) goto err;

	if (BN_GF2m_poly2arr(p, arr, max) > max)

	ret = BN_GF2m_poly2arr(p, arr, max);

	if (!ret || ret > max)

		{

		BNerr(BN_F_BN_GF2M_MOD_EXP,BN_R_INVALID_LENGTH);

		goto err;
@@ -871,6 +877,10 @@ int BN_GF2m_mod_solve_quad_arr(BIGNUM *r, const BIGNUM *a_, const unsigned int p 
	unsigned int j;

	BIGNUM *a, *z, *rho, *w, *w2, *tmp;



	if (!p[0])

		/* reduction mod 1 => return 0 */

		return BN_zero(r);



	BN_CTX_start(ctx);

	a = BN_CTX_get(ctx);

	z = BN_CTX_get(ctx);
@@ -951,7 +961,8 @@ int BN_GF2m_mod_solve_quad(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX * 
	const int max = BN_num_bits(p);

	unsigned int *arr=NULL, ret = 0;

	if ((arr = (unsigned int *)OPENSSL_malloc(sizeof(unsigned int) * max)) == NULL) goto err;

	if (BN_GF2m_poly2arr(p, arr, max) > max)

	ret = BN_GF2m_poly2arr(p, arr, max);

	if (!ret || ret > max)

		{

		BNerr(BN_F_BN_GF2M_MOD_SOLVE_QUAD,BN_R_INVALID_LENGTH);

		goto err;
@@ -963,21 +974,28 @@ int BN_GF2m_mod_solve_quad(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX * 
	return ret;

	}



/* Convert the bit-string representation of a polynomial a into an array

/* Convert the bit-string representation of a polynomial

 * ( \sum_{i=0}^n a_i * x^i , where a_0 is *not* zero) into an array

 * of integers corresponding to the bits with non-zero coefficient.

 * Up to max elements of the array will be filled.  Return value is total

 * number of coefficients that would be extracted if array was large enough.

 */

int BN_GF2m_poly2arr(const BIGNUM *a, unsigned int p[], int max)

	{

	int i, j, k;

	int i, j, k = 0;

	BN_ULONG mask;



	for (k = 0; k < max; k++) p[k] = 0;

	k = 0;

	if (BN_is_zero(a) || !BN_is_bit_set(a, 0))

		/* a_0 == 0 => return error (the unsigned int array

		 * must be terminated by 0)

		 */

		return 0;



	for (i = a->top - 1; i >= 0; i--)

		{

		if (!a->d[i])

			/* skip word if a->d[i] == 0 */

			continue;

		mask = BN_TBIT;

		for (j = BN_BITS2 - 1; j >= 0; j--)

			{
@@ -1001,7 +1019,7 @@ int BN_GF2m_arr2poly(const unsigned int p[], BIGNUM *a) 
	int i;



	BN_zero(a);

	for (i = 0; p[i] > 0; i++)

	for (i = 0; p[i] != 0; i++)

		{

		BN_set_bit(a, p[i]);

		}