Commit eaffe377 authored by Daniele Alessandrelli's avatar Daniele Alessandrelli Committed by Herbert Xu
Browse files

crypto: ecc - Export additional helper functions 



Export the following additional ECC helper functions:
- ecc_alloc_point()
- ecc_free_point()
- vli_num_bits()
- ecc_point_is_zero()

This is done to allow future ECC device drivers to re-use existing code,
thus simplifying their implementation.

Functions are exported using EXPORT_SYMBOL() (instead of
EXPORT_SYMBOL_GPL()) to be consistent with the functions already
exported by crypto/ecc.c.

Exported functions are documented in include/crypto/internal/ecc.h.

Signed-off-by: default avatarDaniele Alessandrelli <daniele.alessandrelli@intel.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent a745d3ac

crypto/ecc.c

+8 −4
Original line number Diff line number Diff line
@@ -81,7 +81,7 @@ static void ecc_free_digits_space(u64 *space) 
	kfree_sensitive(space);

}



static struct ecc_point *ecc_alloc_point(unsigned int ndigits)

struct ecc_point *ecc_alloc_point(unsigned int ndigits)

{

	struct ecc_point *p = kmalloc(sizeof(*p), GFP_KERNEL);
@@ -106,8 +106,9 @@ static struct ecc_point *ecc_alloc_point(unsigned int ndigits) 
	kfree(p);

	return NULL;

}

EXPORT_SYMBOL(ecc_alloc_point);



static void ecc_free_point(struct ecc_point *p)

void ecc_free_point(struct ecc_point *p)

{

	if (!p)

		return;
@@ -116,6 +117,7 @@ static void ecc_free_point(struct ecc_point *p) 
	kfree_sensitive(p->y);

	kfree_sensitive(p);

}

EXPORT_SYMBOL(ecc_free_point);



static void vli_clear(u64 *vli, unsigned int ndigits)

{
@@ -165,7 +167,7 @@ static unsigned int vli_num_digits(const u64 *vli, unsigned int ndigits) 
}



/* Counts the number of bits required for vli. */

static unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits)

unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits)

{

	unsigned int i, num_digits;

	u64 digit;
@@ -180,6 +182,7 @@ static unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits) 


	return ((num_digits - 1) * 64 + i);

}

EXPORT_SYMBOL(vli_num_bits);



/* Set dest from unaligned bit string src. */

void vli_from_be64(u64 *dest, const void *src, unsigned int ndigits)
@@ -1062,11 +1065,12 @@ EXPORT_SYMBOL(vli_mod_inv); 
/* ------ Point operations ------ */



/* Returns true if p_point is the point at infinity, false otherwise. */

static bool ecc_point_is_zero(const struct ecc_point *point)

bool ecc_point_is_zero(const struct ecc_point *point)

{

	return (vli_is_zero(point->x, point->ndigits) &&

		vli_is_zero(point->y, point->ndigits));

}

EXPORT_SYMBOL(ecc_point_is_zero);



/* Point multiplication algorithm using Montgomery's ladder with co-Z

 * coordinates. From https://eprint.iacr.org/2011/338.pdf

include/crypto/internal/ecc.h

+36 −0
Original line number Diff line number Diff line
@@ -225,6 +225,41 @@ void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod, 
void vli_mod_mult_slow(u64 *result, const u64 *left, const u64 *right,

		       const u64 *mod, unsigned int ndigits);



/**

 * vli_num_bits() - Counts the number of bits required for vli.

 *

 * @vli:		vli to check.

 * @ndigits:		Length of the @vli

 *

 * Return: The number of bits required to represent @vli.

 */

unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits);



/**

 * ecc_aloc_point() - Allocate ECC point.

 *

 * @ndigits:		Length of vlis in u64 qwords.

 *

 * Return: Pointer to the allocated point or NULL if allocation failed.

 */

struct ecc_point *ecc_alloc_point(unsigned int ndigits);



/**

 * ecc_free_point() - Free ECC point.

 *

 * @p:			The point to free.

 */

void ecc_free_point(struct ecc_point *p);



/**

 * ecc_point_is_zero() - Check if point is zero.

 *

 * @p:			Point to check for zero.

 *

 * Return: true if point is the point at infinity, false otherwise.

 */

bool ecc_point_is_zero(const struct ecc_point *point);



/**

 * ecc_point_mult_shamir() - Add two points multiplied by scalars

 *
@@ -242,4 +277,5 @@ void ecc_point_mult_shamir(const struct ecc_point *result, 
			   const u64 *x, const struct ecc_point *p,

			   const u64 *y, const struct ecc_point *q,

			   const struct ecc_curve *curve);



#endif