crypto: Add wrappers for OpenSSL BIGNUM and EC_POINT

These new crypto wrappers can be used to implement bignum and EC
operations using various crypto libraries.

Signed-hostap: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2012-12-31 19:40:08 +02:00
parent d136c376f2
commit 619c70a0b2
2 changed files with 456 additions and 0 deletions

View file

@ -457,4 +457,209 @@ int rc4_skip(const u8 *key, size_t keylen, size_t skip,
*/ */
int crypto_get_random(void *buf, size_t len); int crypto_get_random(void *buf, size_t len);
/**
* struct crypto_bignum - bignum
*
* Internal data structure for bignum implementation. The contents is specific
* to the used crypto library.
*/
struct crypto_bignum;
/**
* crypto_bignum_init - Allocate memory for bignum
* Returns: Pointer to allocated bignum or %NULL on failure
*/
struct crypto_bignum * crypto_bignum_init(void);
/**
* crypto_bignum_init_set - Allocate memory for bignum and set the value
* @buf: Buffer with unsigned binary value
* @len: Length of buf in octets
* Returns: Pointer to allocated bignum or %NULL on failure
*/
struct crypto_bignum * crypto_bignum_init_set(const u8 *buf, size_t len);
/**
* crypto_bignum_deinit - Free bignum
* @n: Bignum from crypto_bignum_init() or crypto_bignum_init_set()
* @clear: Whether to clear the value from memory
*/
void crypto_bignum_deinit(struct crypto_bignum *n, int clear);
/**
* crypto_bignum_to_bin - Set binary buffer to unsigned bignum
* @a: Bignum
* @buf: Buffer for the binary number
* @len: Length of @buf in octets
* @padlen: Length in octets to pad the result to or 0 to indicate no padding
* Returns: Number of octets written on success, -1 on failure
*/
int crypto_bignum_to_bin(const struct crypto_bignum *a,
u8 *buf, size_t buflen, size_t padlen);
/**
* crypto_bignum_add - c = a + b
* @a: Bignum
* @b: Bignum
* @c: Bignum; used to store the result of a + b
* Returns: 0 on success, -1 on failure
*/
int crypto_bignum_add(const struct crypto_bignum *a,
const struct crypto_bignum *b,
struct crypto_bignum *c);
/**
* crypto_bignum_mod - c = a % b
* @a: Bignum
* @b: Bignum
* @c: Bignum; used to store the result of a % b
* Returns: 0 on success, -1 on failure
*/
int crypto_bignum_mod(const struct crypto_bignum *a,
const struct crypto_bignum *b,
struct crypto_bignum *c);
/**
* struct crypto_ec - Elliptic curve context
*
* Internal data structure for EC implementation. The contents is specific
* to the used crypto library.
*/
struct crypto_ec;
/**
* crypto_ec_init - Initialize elliptic curve context
* @group: Identifying number for the ECC group (IANA "Group Description"
* attribute registrty for RFC 2409)
* Returns: Pointer to EC context or %NULL on failure
*/
struct crypto_ec * crypto_ec_init(int group);
/**
* crypto_ec_deinit - Deinitialize elliptic curve context
* @e: EC context from crypto_ec_init()
*/
void crypto_ec_deinit(struct crypto_ec *e);
/**
* crypto_ec_prime_len - Get length of the prime in octets
* @e: EC context from crypto_ec_init()
* Returns: Length of the prime defining the group
*/
size_t crypto_ec_prime_len(struct crypto_ec *e);
/**
* struct crypto_ec_point - Elliptic curve point
*
* Internal data structure for EC implementation to represent a point. The
* contents is specific to the used crypto library.
*/
struct crypto_ec_point;
/**
* crypto_ec_point_init - Initialize data for an EC point
* @e: EC context from crypto_ec_init()
* Returns: Pointer to EC point data or %NULL on failure
*/
struct crypto_ec_point * crypto_ec_point_init(struct crypto_ec *e);
/**
* crypto_ec_point_deinit - Deinitialize EC point data
* @p: EC point data from crypto_ec_point_init()
* @clear: Whether to clear the EC point value from memory
*/
void crypto_ec_point_deinit(struct crypto_ec_point *p, int clear);
/**
* crypto_ec_point_to_bin - Write EC point value as binary data
* @e: EC context from crypto_ec_init()
* @p: EC point data from crypto_ec_point_init()
* @x: Buffer for writing the binary data for x coordinate or %NULL if not used
* @y: Buffer for writing the binary data for y coordinate or %NULL if not used
* Returns: 0 on success, -1 on failure
*
* This function can be used to write an EC point as binary data in a format
* that has the x and y coordinates in big endian byte order fields padded to
* the length of the prime defining the group.
*/
int crypto_ec_point_to_bin(struct crypto_ec *e,
const struct crypto_ec_point *point, u8 *x, u8 *y);
/**
* crypto_ec_point_from_bin - Create EC point from binary data
* @e: EC context from crypto_ec_init()
* @val: Binary data to read the EC point from
* Returns: Pointer to EC point data or %NULL on failure
*
* This function readers x and y coordinates of the EC point from the provided
* buffer assuming the values are in big endian byte order with fields padded to
* the length of the prime defining the group.
*/
struct crypto_ec_point * crypto_ec_point_from_bin(struct crypto_ec *e,
const u8 *val);
/**
* crypto_bignum_add - c = a + b
* @e: EC context from crypto_ec_init()
* @a: Bignum
* @b: Bignum
* @c: Bignum; used to store the result of a + b
* Returns: 0 on success, -1 on failure
*/
int crypto_ec_point_add(struct crypto_ec *e, const struct crypto_ec_point *a,
const struct crypto_ec_point *b,
struct crypto_ec_point *c);
/**
* crypto_bignum_mul - res = b * p
* @e: EC context from crypto_ec_init()
* @p: EC point
* @b: Bignum
* @res: EC point; used to store the result of b * p
* Returns: 0 on success, -1 on failure
*/
int crypto_ec_point_mul(struct crypto_ec *e, const struct crypto_ec_point *p,
const struct crypto_bignum *b,
struct crypto_ec_point *res);
/**
* crypto_ec_point_invert - Compute inverse of an EC point
* @e: EC context from crypto_ec_init()
* @p: EC point to invert (and result of the operation)
* Returns: 0 on success, -1 on failure
*/
int crypto_ec_point_invert(struct crypto_ec *e, struct crypto_ec_point *p);
/**
* crypto_ec_point_solve_y_coord - Solve y coordinate for an x coordinate
* @e: EC context from crypto_ec_init()
* @p: EC point to use for the returning the result
* @x: x coordinate
* @y_bit: y-bit (0 or 1) for selecting the y value to use
* Returns: 0 on success, -1 on failure
*/
int crypto_ec_point_solve_y_coord(struct crypto_ec *e,
struct crypto_ec_point *p,
const struct crypto_bignum *x, int y_bit);
/**
* crypto_ec_point_is_at_infinity - Check whether EC point is neutral element
* @e: EC context from crypto_ec_init()
* @p: EC point
* Returns: 1 if the specified EC point is the neutral element of the group or
* 0 if not
*/
int crypto_ec_point_is_at_infinity(struct crypto_ec *e,
const struct crypto_ec_point *p);
/**
* crypto_ec_point_is_on_curve - Check whether EC point is on curve
* @e: EC context from crypto_ec_init()
* @p: EC point
* Returns: 1 if the specified EC point is on the curve or 0 if not
*/
int crypto_ec_point_is_on_curve(struct crypto_ec *e,
const struct crypto_ec_point *p);
#endif /* CRYPTO_H */ #endif /* CRYPTO_H */

View file

@ -19,6 +19,9 @@
#ifdef CONFIG_OPENSSL_CMAC #ifdef CONFIG_OPENSSL_CMAC
#include <openssl/cmac.h> #include <openssl/cmac.h>
#endif /* CONFIG_OPENSSL_CMAC */ #endif /* CONFIG_OPENSSL_CMAC */
#ifdef CONFIG_ECC
#include <openssl/ec.h>
#endif /* CONFIG_ECC */
#include "common.h" #include "common.h"
#include "wpabuf.h" #include "wpabuf.h"
@ -818,3 +821,251 @@ int omac1_aes_128(const u8 *key, const u8 *data, size_t data_len, u8 *mac)
return omac1_aes_128_vector(key, 1, &data, &data_len, mac); return omac1_aes_128_vector(key, 1, &data, &data_len, mac);
} }
#endif /* CONFIG_OPENSSL_CMAC */ #endif /* CONFIG_OPENSSL_CMAC */
struct crypto_bignum * crypto_bignum_init(void)
{
return (struct crypto_bignum *) BN_new();
}
struct crypto_bignum * crypto_bignum_init_set(const u8 *buf, size_t len)
{
BIGNUM *bn = BN_bin2bn(buf, len, NULL);
return (struct crypto_bignum *) bn;
}
void crypto_bignum_deinit(struct crypto_bignum *n, int clear)
{
if (clear)
BN_clear_free((BIGNUM *) n);
else
BN_free((BIGNUM *) n);
}
int crypto_bignum_to_bin(const struct crypto_bignum *a,
u8 *buf, size_t buflen, size_t padlen)
{
int num_bytes, offset;
if (padlen > buflen)
return -1;
num_bytes = BN_num_bytes((const BIGNUM *) a);
if ((size_t) num_bytes > buflen)
return -1;
if (padlen > (size_t) num_bytes)
offset = padlen - num_bytes;
else
offset = 0;
os_memset(buf, 0, offset);
BN_bn2bin((const BIGNUM *) a, buf + offset);
return num_bytes + offset;
}
int crypto_bignum_add(const struct crypto_bignum *a,
const struct crypto_bignum *b,
struct crypto_bignum *c)
{
return BN_add((BIGNUM *) c, (const BIGNUM *) a, (const BIGNUM *) b) ?
0 : -1;
}
int crypto_bignum_mod(const struct crypto_bignum *a,
const struct crypto_bignum *b,
struct crypto_bignum *c)
{
int res;
BN_CTX *bnctx;
bnctx = BN_CTX_new();
if (bnctx == NULL)
return -1;
res = BN_mod((BIGNUM *) c, (const BIGNUM *) a, (const BIGNUM *) b,
bnctx);
BN_CTX_free(bnctx);
return res ? 0 : -1;
}
#ifdef CONFIG_ECC
struct crypto_ec {
EC_GROUP *group;
BN_CTX *bnctx;
size_t prime_len;
};
struct crypto_ec * crypto_ec_init(int group)
{
struct crypto_ec *e;
if (group != 19)
return NULL;
e = os_zalloc(sizeof(*e));
if (e == NULL)
return NULL;
e->prime_len = 32;
e->bnctx = BN_CTX_new();
e->group = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
if (e->group == NULL || e->bnctx == NULL) {
crypto_ec_deinit(e);
e = NULL;
}
return e;
}
void crypto_ec_deinit(struct crypto_ec *e)
{
if (e == NULL)
return;
EC_GROUP_free(e->group);
BN_CTX_free(e->bnctx);
os_free(e);
}
struct crypto_ec_point * crypto_ec_point_init(struct crypto_ec *e)
{
if (e == NULL)
return NULL;
return (struct crypto_ec_point *) EC_POINT_new(e->group);
}
size_t crypto_ec_prime_len(struct crypto_ec *e)
{
return e->prime_len;
}
void crypto_ec_point_deinit(struct crypto_ec_point *p, int clear)
{
if (clear)
EC_POINT_clear_free((EC_POINT *) p);
else
EC_POINT_free((EC_POINT *) p);
}
int crypto_ec_point_to_bin(struct crypto_ec *e,
const struct crypto_ec_point *point, u8 *x, u8 *y)
{
BIGNUM *x_bn, *y_bn;
int ret = -1;
x_bn = BN_new();
y_bn = BN_new();
if (x_bn && y_bn &&
EC_POINT_get_affine_coordinates_GFp(e->group, (EC_POINT *) point,
x_bn, y_bn, e->bnctx)) {
if (x) {
crypto_bignum_to_bin((struct crypto_bignum *) x_bn,
x, e->prime_len, e->prime_len);
}
if (y) {
crypto_bignum_to_bin((struct crypto_bignum *) y_bn,
y, e->prime_len, e->prime_len);
}
ret = 0;
}
BN_free(x_bn);
BN_free(y_bn);
return ret;
}
struct crypto_ec_point * crypto_ec_point_from_bin(struct crypto_ec *e,
const u8 *val)
{
BIGNUM *x, *y;
EC_POINT *elem;
x = BN_bin2bn(val, e->prime_len, NULL);
y = BN_bin2bn(val + e->prime_len, e->prime_len, NULL);
elem = EC_POINT_new(e->group);
if (x == NULL || y == NULL || elem == NULL) {
BN_free(x);
BN_free(y);
EC_POINT_free(elem);
return NULL;
}
if (!EC_POINT_set_affine_coordinates_GFp(e->group, elem, x, y,
e->bnctx)) {
EC_POINT_free(elem);
elem = NULL;
}
BN_free(x);
BN_free(y);
return (struct crypto_ec_point *) elem;
}
int crypto_ec_point_add(struct crypto_ec *e, const struct crypto_ec_point *a,
const struct crypto_ec_point *b,
struct crypto_ec_point *c)
{
return EC_POINT_add(e->group, (EC_POINT *) c, (const EC_POINT *) a,
(const EC_POINT *) b, e->bnctx) ? 0 : -1;
}
int crypto_ec_point_mul(struct crypto_ec *e, const struct crypto_ec_point *p,
const struct crypto_bignum *b,
struct crypto_ec_point *res)
{
return EC_POINT_mul(e->group, (EC_POINT *) res, NULL,
(const EC_POINT *) p, (const BIGNUM *) b, e->bnctx)
? 0 : -1;
}
int crypto_ec_point_invert(struct crypto_ec *e, struct crypto_ec_point *p)
{
return EC_POINT_invert(e->group, (EC_POINT *) p, e->bnctx) ? 0 : -1;
}
int crypto_ec_point_solve_y_coord(struct crypto_ec *e,
struct crypto_ec_point *p,
const struct crypto_bignum *x, int y_bit)
{
if (!EC_POINT_set_compressed_coordinates_GFp(e->group, (EC_POINT *) p,
(const BIGNUM *) x, y_bit,
e->bnctx) ||
!EC_POINT_is_on_curve(e->group, (EC_POINT *) p, e->bnctx))
return -1;
return 0;
}
int crypto_ec_point_is_at_infinity(struct crypto_ec *e,
const struct crypto_ec_point *p)
{
return EC_POINT_is_at_infinity(e->group, (const EC_POINT *) p);
}
int crypto_ec_point_is_on_curve(struct crypto_ec *e,
const struct crypto_ec_point *p)
{
return EC_POINT_is_on_curve(e->group, (const EC_POINT *) p, e->bnctx);
}
#endif /* CONFIG_ECC */