Commit message: Fix for CVE-2014-0076

Fix for the attack described in the paper "Recovering OpenSSL
ECDSA Nonces Using the FLUSH+RELOAD Cache Side-channel Attack"
by Yuval Yarom and Naomi Benger. Details can be obtained from:
http://eprint.iacr.org/2014/140

Thanks to Yuval Yarom and Naomi Benger for discovering this
flaw and to Yuval Yarom for supplying a fix.
(cherry picked from commit 2198be3483259de374f91e57d247d0fc667aef29)

Conflicts:

	CHANGES
CVE: CVE-2014-0076
CWE: CWE-310
Vulnerability description: The Montgomery ladder implementation in OpenSSL through 1.0.0l does not ensure that certain swap operations have a constant-time behavior, which makes it easier for local users to obtain ECDSA nonces via a FLUSH+RELOAD cache side-channel attack.

Project: openssl

int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
	{
	int i;
	BN_ULONG aa,bb;

	aa=a[n-1];
	bb=b[n-1];
	if (aa != bb) return((aa > bb)?1:-1);
	for (i=n-2; i>=0; i--)
		{
		aa=a[i];
		bb=b[i];
		if (aa != bb) return((aa > bb)?1:-1);
		}
	return(0);
	}

Project: openssl

void BN_set_params(int mult, int high, int low, int mont)
	{
	if (mult >= 0)
		{
		if (mult > (int)(sizeof(int)*8)-1)
			mult=sizeof(int)*8-1;
		bn_limit_bits=mult;
		bn_limit_num=1<<mult;
		}
	if (high >= 0)
		{
		if (high > (int)(sizeof(int)*8)-1)
			high=sizeof(int)*8-1;
		bn_limit_bits_high=high;
		bn_limit_num_high=1<<high;
		}
	if (low >= 0)
		{
		if (low > (int)(sizeof(int)*8)-1)
			low=sizeof(int)*8-1;
		bn_limit_bits_low=low;
		bn_limit_num_low=1<<low;
		}
	if (mont >= 0)
		{
		if (mont > (int)(sizeof(int)*8)-1)
			mont=sizeof(int)*8-1;
		bn_limit_bits_mont=mont;
		bn_limit_num_mont=1<<mont;
		}
	}

Project: openssl

int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
	int cl, int dl)
	{
	int n,i;
	n = cl-1;

	if (dl < 0)
		{
		for (i=dl; i<0; i++)
			{
			if (b[n-i] != 0)
				return -1; /* a < b */
			}
		}
	if (dl > 0)
		{
		for (i=dl; i>0; i--)
			{
			if (a[n+i] != 0)
				return 1; /* a > b */
			}
		}
	return bn_cmp_words(a,b,cl);
	}

Project: openssl

BIGNUM *bn_dup_expand(const BIGNUM *b, int words)
	{
	BIGNUM *r = NULL;

	bn_check_top(b);

	/* This function does not work if
	 *      words <= b->dmax && top < words
	 * because BN_dup() does not preserve 'dmax'!
	 * (But bn_dup_expand() is not used anywhere yet.)
	 */

	if (words > b->dmax)
		{
		BN_ULONG *a = bn_expand_internal(b, words);

		if (a)
			{
			r = BN_new();
			if (r)
				{
				r->top = b->top;
				r->dmax = words;
				r->neg = b->neg;
				r->d = a;
				}
			else
				{
				/* r == NULL, BN_new failure */
				OPENSSL_free(a);
				}
			}
		/* If a == NULL, there was an error in allocation in
		   bn_expand_internal(), and NULL should be returned */
		}
	else
		{
		r = BN_dup(b);
		}

	bn_check_top(r);
	return r;
	}

Project: openssl

int ec_GF2m_precompute_mult(EC_GROUP *group, BN_CTX *ctx)
	{
	return ec_wNAF_precompute_mult(group, ctx);
 	}

Project: openssl

int BN_cmp(const BIGNUM *a, const BIGNUM *b)
	{
	int i;
	int gt,lt;
	BN_ULONG t1,t2;

	if ((a == NULL) || (b == NULL))
		{
		if (a != NULL)
			return(-1);
		else if (b != NULL)
			return(1);
		else
			return(0);
		}

	bn_check_top(a);
	bn_check_top(b);

	if (a->neg != b->neg)
		{
		if (a->neg)
			return(-1);
		else	return(1);
		}
	if (a->neg == 0)
		{ gt=1; lt= -1; }
	else	{ gt= -1; lt=1; }

	if (a->top > b->top) return(gt);
	if (a->top < b->top) return(lt);
	for (i=a->top-1; i>=0; i--)
		{
		t1=a->d[i];
		t2=b->d[i];
		if (t1 > t2) return(gt);
		if (t1 < t2) return(lt);
		}
	return(0);
	}

Project: openssl

static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
	{
	BN_ULONG *A,*a = NULL;
	const BN_ULONG *B;
	int i;

	bn_check_top(b);

	if (words > (INT_MAX/(4*BN_BITS2)))
		{
		BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG);
		return NULL;
		}
	if (BN_get_flags(b,BN_FLG_STATIC_DATA))
		{
		BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
		return(NULL);
		}
	a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*words);
	if (A == NULL)
		{
		BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);
		return(NULL);
		}
#if 1
	B=b->d;
	/* Check if the previous number needs to be copied */
	if (B != NULL)
		{
		for (i=b->top>>2; i>0; i--,A+=4,B+=4)
			{
			/*
			 * The fact that the loop is unrolled
			 * 4-wise is a tribute to Intel. It's
			 * the one that doesn't have enough
			 * registers to accomodate more data.
			 * I'd unroll it 8-wise otherwise:-)
			 *
			 *		<appro@fy.chalmers.se>
			 */
			BN_ULONG a0,a1,a2,a3;
			a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
			A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
			}
		switch (b->top&3)
			{
		case 3:	A[2]=B[2];
		case 2:	A[1]=B[1];
		case 1:	A[0]=B[0];
		case 0: /* workaround for ultrix cc: without 'case 0', the optimizer does
		         * the switch table by doing a=top&3; a--; goto jump_table[a];
		         * which fails for top== 0 */
			;
			}
		}

#else
	memset(A,0,sizeof(BN_ULONG)*words);
	memcpy(A,b->d,sizeof(b->d[0])*b->top);
#endif
		
	return(a);
	}

Project: openssl

void BN_clear_free(BIGNUM *a)
	{
	int i;

	if (a == NULL) return;
	bn_check_top(a);
	if (a->d != NULL)
		{
		OPENSSL_cleanse(a->d,a->dmax*sizeof(a->d[0]));
		if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
			OPENSSL_free(a->d);
		}
	i=BN_get_flags(a,BN_FLG_MALLOCED);
	OPENSSL_cleanse(a,sizeof(BIGNUM));
	if (i)
		OPENSSL_free(a);
	}

Project: openssl

static int gf2m_Mdouble(const EC_GROUP *group, BIGNUM *x, BIGNUM *z, BN_CTX *ctx)
	{
	BIGNUM *t1;
	int ret = 0;
	
	/* Since Mdouble is static we can guarantee that ctx != NULL. */
	BN_CTX_start(ctx);
	t1 = BN_CTX_get(ctx);
	if (t1 == NULL) goto err;

	if (!group->meth->field_sqr(group, x, x, ctx)) goto err;
	if (!group->meth->field_sqr(group, t1, z, ctx)) goto err;
	if (!group->meth->field_mul(group, z, x, t1, ctx)) goto err;
	if (!group->meth->field_sqr(group, x, x, ctx)) goto err;
	if (!group->meth->field_sqr(group, t1, t1, ctx)) goto err;
	if (!group->meth->field_mul(group, t1, &group->b, t1, ctx)) goto err;
	if (!BN_GF2m_add(x, x, t1)) goto err;

	ret = 1;

 err:
	BN_CTX_end(ctx);
	return ret;
	}

Project: openssl

const BIGNUM *BN_value_one(void)
	{
	static const BN_ULONG data_one=1L;
	static const BIGNUM const_one={(BN_ULONG *)&data_one,1,1,0,BN_FLG_STATIC_DATA};

	return(&const_one);
	}

Project: openssl

int BN_mask_bits(BIGNUM *a, int n)
	{
	int b,w;

	bn_check_top(a);
	if (n < 0) return 0;

	w=n/BN_BITS2;
	b=n%BN_BITS2;
	if (w >= a->top) return 0;
	if (b == 0)
		a->top=w;
	else
		{
		a->top=w+1;
		a->d[w]&= ~(BN_MASK2<<b);
		}
	bn_correct_top(a);
	return(1);
	}

Project: openssl

static int gf2m_Mxy(const EC_GROUP *group, const BIGNUM *x, const BIGNUM *y, BIGNUM *x1, 
	BIGNUM *z1, BIGNUM *x2, BIGNUM *z2, BN_CTX *ctx)
	{
	BIGNUM *t3, *t4, *t5;
	int ret = 0;
	
	if (BN_is_zero(z1))
		{
		BN_zero(x2);
		BN_zero(z2);
		return 1;
		}
	
	if (BN_is_zero(z2))
		{
		if (!BN_copy(x2, x)) return 0;
		if (!BN_GF2m_add(z2, x, y)) return 0;
		return 2;
		}
		
	/* Since Mxy is static we can guarantee that ctx != NULL. */
	BN_CTX_start(ctx);
	t3 = BN_CTX_get(ctx);
	t4 = BN_CTX_get(ctx);
	t5 = BN_CTX_get(ctx);
	if (t5 == NULL) goto err;

	if (!BN_one(t5)) goto err;

	if (!group->meth->field_mul(group, t3, z1, z2, ctx)) goto err;

	if (!group->meth->field_mul(group, z1, z1, x, ctx)) goto err;
	if (!BN_GF2m_add(z1, z1, x1)) goto err;
	if (!group->meth->field_mul(group, z2, z2, x, ctx)) goto err;
	if (!group->meth->field_mul(group, x1, z2, x1, ctx)) goto err;
	if (!BN_GF2m_add(z2, z2, x2)) goto err;

	if (!group->meth->field_mul(group, z2, z2, z1, ctx)) goto err;
	if (!group->meth->field_sqr(group, t4, x, ctx)) goto err;
	if (!BN_GF2m_add(t4, t4, y)) goto err;
	if (!group->meth->field_mul(group, t4, t4, t3, ctx)) goto err;
	if (!BN_GF2m_add(t4, t4, z2)) goto err;

	if (!group->meth->field_mul(group, t3, t3, x, ctx)) goto err;
	if (!group->meth->field_div(group, t3, t5, t3, ctx)) goto err;
	if (!group->meth->field_mul(group, t4, t3, t4, ctx)) goto err;
	if (!group->meth->field_mul(group, x2, x1, t3, ctx)) goto err;
	if (!BN_GF2m_add(z2, x2, x)) goto err;

	if (!group->meth->field_mul(group, z2, z2, t4, ctx)) goto err;
	if (!BN_GF2m_add(z2, z2, y)) goto err;

	ret = 2;

 err:
	BN_CTX_end(ctx);
	return ret;
	}

Project: openssl

void BN_init(BIGNUM *a)
	{
	memset(a,0,sizeof(BIGNUM));
	bn_check_top(a);
	}

Project: openssl

int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
	{
	int i;
	BN_ULONG t1,t2,*ap,*bp;

	bn_check_top(a);
	bn_check_top(b);

	i=a->top-b->top;
	if (i != 0) return(i);
	ap=a->d;
	bp=b->d;
	for (i=a->top-1; i>=0; i--)
		{
		t1= ap[i];
		t2= bp[i];
		if (t1 != t2)
			return((t1 > t2) ? 1 : -1);
		}
	return(0);
	}

Project: openssl

void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
	{
	BN_ULONG t;
	int i;

	bn_wcheck_size(a, nwords);
	bn_wcheck_size(b, nwords);

	assert(a != b);
	assert((condition & (condition - 1)) == 0);
	assert(sizeof(BN_ULONG) >= sizeof(int));

	condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;

	t = (a->top^b->top) & condition;
	a->top ^= t;
	b->top ^= t;

#define BN_CONSTTIME_SWAP(ind) \
	do { \
		t = (a->d[ind] ^ b->d[ind]) & condition; \
		a->d[ind] ^= t; \
		b->d[ind] ^= t; \
	} while (0)


	switch (nwords) {
	default:
		for (i = 10; i < nwords; i++) 
			BN_CONSTTIME_SWAP(i);
		/* Fallthrough */
	case 10: BN_CONSTTIME_SWAP(9); /* Fallthrough */
	case 9: BN_CONSTTIME_SWAP(8); /* Fallthrough */
	case 8: BN_CONSTTIME_SWAP(7); /* Fallthrough */
	case 7: BN_CONSTTIME_SWAP(6); /* Fallthrough */
	case 6: BN_CONSTTIME_SWAP(5); /* Fallthrough */
	case 5: BN_CONSTTIME_SWAP(4); /* Fallthrough */
	case 4: BN_CONSTTIME_SWAP(3); /* Fallthrough */
	case 3: BN_CONSTTIME_SWAP(2); /* Fallthrough */
	case 2: BN_CONSTTIME_SWAP(1); /* Fallthrough */
	case 1: BN_CONSTTIME_SWAP(0);
	}
#undef BN_CONSTTIME_SWAP
}

Project: openssl

int ec_GF2m_simple_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
	size_t num, const EC_POINT *points[], const BIGNUM *scalars[], BN_CTX *ctx)
	{
	BN_CTX *new_ctx = NULL;
	int ret = 0;
	size_t i;
	EC_POINT *p=NULL;
	EC_POINT *acc = NULL;

	if (ctx == NULL)
		{
		ctx = new_ctx = BN_CTX_new();
		if (ctx == NULL)
			return 0;
		}

	/* This implementation is more efficient than the wNAF implementation for 2
	 * or fewer points.  Use the ec_wNAF_mul implementation for 3 or more points,
	 * or if we can perform a fast multiplication based on precomputation.
	 */
	if ((scalar && (num > 1)) || (num > 2) || (num == 0 && EC_GROUP_have_precompute_mult(group)))
		{
		ret = ec_wNAF_mul(group, r, scalar, num, points, scalars, ctx);
		goto err;
		}

	if ((p = EC_POINT_new(group)) == NULL) goto err;
	if ((acc = EC_POINT_new(group)) == NULL) goto err;

	if (!EC_POINT_set_to_infinity(group, acc)) goto err;

	if (scalar)
		{
		if (!ec_GF2m_montgomery_point_multiply(group, p, scalar, group->generator, ctx)) goto err;
		if (BN_is_negative(scalar))
			if (!group->meth->invert(group, p, ctx)) goto err;
		if (!group->meth->add(group, acc, acc, p, ctx)) goto err;
		}

	for (i = 0; i < num; i++)
		{
		if (!ec_GF2m_montgomery_point_multiply(group, p, scalars[i], points[i], ctx)) goto err;
		if (BN_is_negative(scalars[i]))
			if (!group->meth->invert(group, p, ctx)) goto err;
		if (!group->meth->add(group, acc, acc, p, ctx)) goto err;
		}

	if (!EC_POINT_copy(r, acc)) goto err;

	ret = 1;

  err:
	if (p) EC_POINT_free(p);
	if (acc) EC_POINT_free(acc);
	if (new_ctx != NULL)
		BN_CTX_free(new_ctx);
	return ret;
	}

Project: openssl

int ec_GF2m_have_precompute_mult(const EC_GROUP *group)
	{
	return ec_wNAF_have_precompute_mult(group);
 	}

Project: openssl

int BN_set_word(BIGNUM *a, BN_ULONG w)
	{
	bn_check_top(a);
	if (bn_expand(a,(int)sizeof(BN_ULONG)*8) == NULL) return(0);
	a->neg = 0;
	a->d[0] = w;
	a->top = (w ? 1 : 0);
	bn_check_top(a);
	return(1);
	}

Project: openssl

BIGNUM *bn_expand2(BIGNUM *b, int words)
	{
	bn_check_top(b);

	if (words > b->dmax)
		{
		BN_ULONG *a = bn_expand_internal(b, words);
		if(!a) return NULL;
		if(b->d) OPENSSL_free(b->d);
		b->d=a;
		b->dmax=words;
		}

/* None of this should be necessary because of what b->top means! */
#if 0
	/* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
	if (b->top < b->dmax)
		{
		int i;
		BN_ULONG *A = &(b->d[b->top]);
		for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
			{
			A[0]=0; A[1]=0; A[2]=0; A[3]=0;
			A[4]=0; A[5]=0; A[6]=0; A[7]=0;
			}
		for (i=(b->dmax - b->top)&7; i>0; i--,A++)
			A[0]=0;
		assert(A == &(b->d[b->dmax]));
		}
#endif
	bn_check_top(b);
	return b;
	}

Project: openssl

BIGNUM *BN_dup(const BIGNUM *a)
	{
	BIGNUM *t;

	if (a == NULL) return NULL;
	bn_check_top(a);

	t = BN_new();
	if (t == NULL) return NULL;
	if(!BN_copy(t, a))
		{
		BN_free(t);
		return NULL;
		}
	bn_check_top(t);
	return t;
	}

Project: openssl

int BN_bn2bin(const BIGNUM *a, unsigned char *to)
	{
	int n,i;
	BN_ULONG l;

	bn_check_top(a);
	n=i=BN_num_bytes(a);
	while (i--)
		{
		l=a->d[i/BN_BYTES];
		*(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;
		}
	return(n);
	}

Project: openssl

int BN_clear_bit(BIGNUM *a, int n)
	{
	int i,j;

	bn_check_top(a);
	if (n < 0) return 0;

	i=n/BN_BITS2;
	j=n%BN_BITS2;
	if (a->top <= i) return(0);

	a->d[i]&=(~(((BN_ULONG)1)<<j));
	bn_correct_top(a);
	return(1);
	}

Project: openssl

static int gf2m_Madd(const EC_GROUP *group, const BIGNUM *x, BIGNUM *x1, BIGNUM *z1, 
	const BIGNUM *x2, const BIGNUM *z2, BN_CTX *ctx)
	{
	BIGNUM *t1, *t2;
	int ret = 0;
	
	/* Since Madd is static we can guarantee that ctx != NULL. */
	BN_CTX_start(ctx);
	t1 = BN_CTX_get(ctx);
	t2 = BN_CTX_get(ctx);
	if (t2 == NULL) goto err;

	if (!BN_copy(t1, x)) goto err;
	if (!group->meth->field_mul(group, x1, x1, z2, ctx)) goto err;
	if (!group->meth->field_mul(group, z1, z1, x2, ctx)) goto err;
	if (!group->meth->field_mul(group, t2, x1, z1, ctx)) goto err;
	if (!BN_GF2m_add(z1, z1, x1)) goto err;
	if (!group->meth->field_sqr(group, z1, z1, ctx)) goto err;
	if (!group->meth->field_mul(group, x1, z1, t1, ctx)) goto err;
	if (!BN_GF2m_add(x1, x1, t2)) goto err;

	ret = 1;

 err:
	BN_CTX_end(ctx);
	return ret;
	}

Project: openssl

void BN_swap(BIGNUM *a, BIGNUM *b)
	{
	int flags_old_a, flags_old_b;
	BN_ULONG *tmp_d;
	int tmp_top, tmp_dmax, tmp_neg;
	
	bn_check_top(a);
	bn_check_top(b);

	flags_old_a = a->flags;
	flags_old_b = b->flags;

	tmp_d = a->d;
	tmp_top = a->top;
	tmp_dmax = a->dmax;
	tmp_neg = a->neg;
	
	a->d = b->d;
	a->top = b->top;
	a->dmax = b->dmax;
	a->neg = b->neg;
	
	b->d = tmp_d;
	b->top = tmp_top;
	b->dmax = tmp_dmax;
	b->neg = tmp_neg;
	
	a->flags = (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
	b->flags = (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
	bn_check_top(a);
	bn_check_top(b);
	}

Project: openssl

int BN_num_bits_word(BN_ULONG l)
	{
	__fips_constseg
	static const unsigned char bits[256]={
		0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
		5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
		6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
		6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
		7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
		};

#if defined(SIXTY_FOUR_BIT_LONG)
	if (l & 0xffffffff00000000L)
		{
		if (l & 0xffff000000000000L)
			{
			if (l & 0xff00000000000000L)
				{
				return(bits[(int)(l>>56)]+56);
				}
			else	return(bits[(int)(l>>48)]+48);
			}
		else
			{
			if (l & 0x0000ff0000000000L)
				{
				return(bits[(int)(l>>40)]+40);
				}
			else	return(bits[(int)(l>>32)]+32);
			}
		}
	else
#else
#ifdef SIXTY_FOUR_BIT
	if (l & 0xffffffff00000000LL)
		{
		if (l & 0xffff000000000000LL)
			{
			if (l & 0xff00000000000000LL)
				{
				return(bits[(int)(l>>56)]+56);
				}
			else	return(bits[(int)(l>>48)]+48);
			}
		else
			{
			if (l & 0x0000ff0000000000LL)
				{
				return(bits[(int)(l>>40)]+40);
				}
			else	return(bits[(int)(l>>32)]+32);
			}
		}
	else
#endif
#endif
		{
#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
		if (l & 0xffff0000L)
			{
			if (l & 0xff000000L)
				return(bits[(int)(l>>24L)]+24);
			else	return(bits[(int)(l>>16L)]+16);
			}
		else
#endif
			{
#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
			if (l & 0xff00L)
				return(bits[(int)(l>>8)]+8);
			else	
#endif
				return(bits[(int)(l   )]  );
			}
		}
	}

Project: openssl

int BN_is_bit_set(const BIGNUM *a, int n)
	{
	int i,j;

	bn_check_top(a);
	if (n < 0) return 0;
	i=n/BN_BITS2;
	j=n%BN_BITS2;
	if (a->top <= i) return 0;
	return (int)(((a->d[i])>>j)&((BN_ULONG)1));
	}

Project: openssl

BIGNUM *BN_new(void)
	{
	BIGNUM *ret;

	if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
		{
		BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
		return(NULL);
		}
	ret->flags=BN_FLG_MALLOCED;
	ret->top=0;
	ret->neg=0;
	ret->dmax=0;
	ret->d=NULL;
	bn_check_top(ret);
	return(ret);
	}

Project: openssl

void BN_set_negative(BIGNUM *a, int b)
	{
	if (b && !BN_is_zero(a))
		a->neg = 1;
	else
		a->neg = 0;
	}

Project: openssl

int BN_num_bits(const BIGNUM *a)
	{
	int i = a->top - 1;
	bn_check_top(a);

	if (BN_is_zero(a)) return 0;
	return ((i*BN_BITS2) + BN_num_bits_word(a->d[i]));
	}

Project: openssl

int BN_set_bit(BIGNUM *a, int n)
	{
	int i,j,k;

	if (n < 0)
		return 0;

	i=n/BN_BITS2;
	j=n%BN_BITS2;
	if (a->top <= i)
		{
		if (bn_wexpand(a,i+1) == NULL) return(0);
		for(k=a->top; k<i+1; k++)
			a->d[k]=0;
		a->top=i+1;
		}

	a->d[i]|=(((BN_ULONG)1)<<j);
	bn_check_top(a);
	return(1);
	}

Project: openssl

BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
	{
	unsigned int i,m;
	unsigned int n;
	BN_ULONG l;
	BIGNUM  *bn = NULL;

	if (ret == NULL)
		ret = bn = BN_new();
	if (ret == NULL) return(NULL);
	bn_check_top(ret);
	l=0;
	n=len;
	if (n == 0)
		{
		ret->top=0;
		return(ret);
		}
	i=((n-1)/BN_BYTES)+1;
	m=((n-1)%(BN_BYTES));
	if (bn_wexpand(ret, (int)i) == NULL)
		{
		if (bn) BN_free(bn);
		return NULL;
		}
	ret->top=i;
	ret->neg=0;
	while (n--)
		{
		l=(l<<8L)| *(s++);
		if (m-- == 0)
			{
			ret->d[--i]=l;
			l=0;
			m=BN_BYTES-1;
			}
		}
	/* need to call this due to clear byte at top if avoiding
	 * having the top bit set (-ve number) */
	bn_correct_top(ret);
	return(ret);
	}

Project: openssl

int BN_get_params(int which)
	{
	if      (which == 0) return(bn_limit_bits);
	else if (which == 1) return(bn_limit_bits_high);
	else if (which == 2) return(bn_limit_bits_low);
	else if (which == 3) return(bn_limit_bits_mont);
	else return(0);
	}

Project: openssl

BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
	{
	int i;
	BN_ULONG *A;
	const BN_ULONG *B;

	bn_check_top(b);

	if (a == b) return(a);
	if (bn_wexpand(a,b->top) == NULL) return(NULL);

#if 1
	A=a->d;
	B=b->d;
	for (i=b->top>>2; i>0; i--,A+=4,B+=4)
		{
		BN_ULONG a0,a1,a2,a3;
		a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
		A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
		}
	switch (b->top&3)
		{
		case 3: A[2]=B[2];
		case 2: A[1]=B[1];
		case 1: A[0]=B[0];
		case 0: ; /* ultrix cc workaround, see comments in bn_expand_internal */
		}
#else
	memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
#endif

	a->top=b->top;
	a->neg=b->neg;
	bn_check_top(a);
	return(a);
	}

Project: openssl

void BN_clear(BIGNUM *a)
	{
	bn_check_top(a);
	if (a->d != NULL)
		memset(a->d,0,a->dmax*sizeof(a->d[0]));
	a->top=0;
	a->neg=0;
	}

Project: openssl

void BN_free(BIGNUM *a)
	{
	if (a == NULL) return;
	bn_check_top(a);
	if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
		OPENSSL_free(a->d);
	if (a->flags & BN_FLG_MALLOCED)
		OPENSSL_free(a);
	else
		{
#ifndef OPENSSL_NO_DEPRECATED
		a->flags|=BN_FLG_FREE;
#endif
		a->d = NULL;
		}
	}

Project: openssl

BN_ULONG BN_get_word(const BIGNUM *a)
	{
	if (a->top > 1)
		return BN_MASK2;
	else if (a->top == 1)
		return a->d[0];
	/* a->top == 0 */
	return 0;
	}

Project: openssl

static int ec_GF2m_montgomery_point_multiply(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
	const EC_POINT *point, BN_CTX *ctx)
	{
	BIGNUM *x1, *x2, *z1, *z2;
	int ret = 0, i;
	BN_ULONG mask,word;

	if (r == point)
		{
		ECerr(EC_F_EC_GF2M_MONTGOMERY_POINT_MULTIPLY, EC_R_INVALID_ARGUMENT);
		return 0;
		}
	
	/* if result should be point at infinity */
	if ((scalar == NULL) || BN_is_zero(scalar) || (point == NULL) || 
		EC_POINT_is_at_infinity(group, point))
		{
		return EC_POINT_set_to_infinity(group, r);
		}

	/* only support affine coordinates */
	if (!point->Z_is_one) return 0;

	/* Since point_multiply is static we can guarantee that ctx != NULL. */
	BN_CTX_start(ctx);
	x1 = BN_CTX_get(ctx);
	z1 = BN_CTX_get(ctx);
	if (z1 == NULL) goto err;

	x2 = &r->X;
	z2 = &r->Y;

	bn_wexpand(x1, group->field.top);
	bn_wexpand(z1, group->field.top);
	bn_wexpand(x2, group->field.top);
	bn_wexpand(z2, group->field.top);

	if (!BN_GF2m_mod_arr(x1, &point->X, group->poly)) goto err; /* x1 = x */
	if (!BN_one(z1)) goto err; /* z1 = 1 */
	if (!group->meth->field_sqr(group, z2, x1, ctx)) goto err; /* z2 = x1^2 = x^2 */
	if (!group->meth->field_sqr(group, x2, z2, ctx)) goto err;
	if (!BN_GF2m_add(x2, x2, &group->b)) goto err; /* x2 = x^4 + b */

	/* find top most bit and go one past it */
	i = scalar->top - 1;
	mask = BN_TBIT;
	word = scalar->d[i];
	while (!(word & mask)) mask >>= 1;
	mask >>= 1;
	/* if top most bit was at word break, go to next word */
	if (!mask) 
		{
		i--;
		mask = BN_TBIT;
		}

	for (; i >= 0; i--)
		{
		word = scalar->d[i];
		while (mask)
			{
			BN_consttime_swap(word & mask, x1, x2, group->field.top);
			BN_consttime_swap(word & mask, z1, z2, group->field.top);
			if (!gf2m_Madd(group, &point->X, x2, z2, x1, z1, ctx)) goto err;
			if (!gf2m_Mdouble(group, x1, z1, ctx)) goto err;
			BN_consttime_swap(word & mask, x1, x2, group->field.top);
			BN_consttime_swap(word & mask, z1, z2, group->field.top);
			mask >>= 1;
			}
		mask = BN_TBIT;
		}

	/* convert out of "projective" coordinates */
	i = gf2m_Mxy(group, &point->X, &point->Y, x1, z1, x2, z2, ctx);
	if (i == 0) goto err;
	else if (i == 1) 
		{
		if (!EC_POINT_set_to_infinity(group, r)) goto err;
		}
	else
		{
		if (!BN_one(&r->Z)) goto err;
		r->Z_is_one = 1;
		}

	/* GF(2^m) field elements should always have BIGNUM::neg = 0 */
	BN_set_negative(&r->X, 0);
	BN_set_negative(&r->Y, 0);

	ret = 1;

 err:
	BN_CTX_end(ctx);
	return ret;
	}