[PATCH v8 07/10] crypto: ecc - make ecc into separate module

Vitaly Chikunov
2019-03-26T12:59:44Z

ecc.c have algorithms that could be used togeter by ecdh and ecrdsa.
Make it separate module. Add CRYPTO_ECC into Kconfig. EXPORT_SYMBOL and
document to what seems appropriate. Move structs ecc_point and ecc_curve
from ecc_curve_defs.h into ecc.h.

No code changes.

Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
---
crypto/Kconfig | 4 ++
crypto/Makefile | 2 +-
crypto/ecc.c | 25 +++++++++----
crypto/ecc.h | 99 +++++++++++++++++++++++++++++++++++++++++++++++++
crypto/ecc_curve_defs.h | 15 --------
5 files changed, 122 insertions(+), 23 deletions(-)

diff --git a/crypto/Kconfig b/crypto/Kconfig
index b8493d470550..291dda4e8ebf 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -248,8 +248,12 @@ config CRYPTO_DH
help
Generic implementation of the Diffie-Hellman algorithm.

+config CRYPTO_ECC
+ tristate
+
config CRYPTO_ECDH
tristate "ECDH algorithm"
+ select CRYPTO_ECC
select CRYPTO_KPP
select CRYPTO_RNG_DEFAULT
help
diff --git a/crypto/Makefile b/crypto/Makefile
index fb5bf2a3a666..b5685a01ad31 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -147,8 +147,8 @@ obj-$(CONFIG_CRYPTO_USER_API_RNG) += algif_rng.o
obj-$(CONFIG_CRYPTO_USER_API_AEAD) += algif_aead.o
obj-$(CONFIG_CRYPTO_ZSTD) += zstd.o
obj-$(CONFIG_CRYPTO_OFB) += ofb.o
+obj-$(CONFIG_CRYPTO_ECC) += ecc.o

-ecdh_generic-y := ecc.o
ecdh_generic-y += ecdh.o
ecdh_generic-y += ecdh_helper.o
obj-$(CONFIG_CRYPTO_ECDH) += ecdh_generic.o
diff --git a/crypto/ecc.c b/crypto/ecc.c
index ed1237115066..5f36792d143d 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -24,6 +24,7 @@
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

+#include <linux/module.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/swab.h>
@@ -112,7 +113,7 @@ static void vli_clear(u64 *vli, unsigned int ndigits)
}

/* Returns true if vli == 0, false otherwise. */
-static bool vli_is_zero(const u64 *vli, unsigned int ndigits)
+bool vli_is_zero(const u64 *vli, unsigned int ndigits)
{
int i;

@@ -123,6 +124,7 @@ static bool vli_is_zero(const u64 *vli, unsigned int ndigits)

return true;
}
+EXPORT_SYMBOL(vli_is_zero);

/* Returns nonzero if bit bit of vli is set. */
static u64 vli_test_bit(const u64 *vli, unsigned int bit)
@@ -171,7 +173,7 @@ static void vli_set(u64 *dest, const u64 *src, unsigned int ndigits)
}

/* Returns sign of left - right. */
-static int vli_cmp(const u64 *left, const u64 *right, unsigned int ndigits)
+int vli_cmp(const u64 *left, const u64 *right, unsigned int ndigits)
{
int i;

@@ -184,6 +186,7 @@ static int vli_cmp(const u64 *left, const u64 *right, unsigned int ndigits)

return 0;
}
+EXPORT_SYMBOL(vli_cmp);

/* Computes result = in << c, returning carry. Can modify in place
* (if result == in). 0 < shift < 64.
@@ -240,7 +243,7 @@ static u64 vli_add(u64 *result, const u64 *left, const u64 *right,
}

/* Computes result = left - right, returning borrow. Can modify in place. */
-static u64 vli_sub(u64 *result, const u64 *left, const u64 *right,
+u64 vli_sub(u64 *result, const u64 *left, const u64 *right,
unsigned int ndigits)
{
u64 borrow = 0;
@@ -258,6 +261,7 @@ static u64 vli_sub(u64 *result, const u64 *left, const u64 *right,

return borrow;
}
+EXPORT_SYMBOL(vli_sub);

static uint128_t mul_64_64(u64 left, u64 right)
{
@@ -557,7 +561,7 @@ static void vli_mod_square_fast(u64 *result, const u64 *left,
* See "From Euclid's GCD to Montgomery Multiplication to the Great Divide"
* https://labs.oracle.com/techrep/2001/smli_tr-2001-95.pdf
*/
-static void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod,
+void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod,
unsigned int ndigits)
{
u64 a[ECC_MAX_DIGITS], b[ECC_MAX_DIGITS];
@@ -630,6 +634,7 @@ static void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod,

vli_set(result, u, ndigits);
}
+EXPORT_SYMBOL(vli_mod_inv);

/* ------ Point operations ------ */

@@ -948,6 +953,7 @@ int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,

return __ecc_is_key_valid(curve, private_key, ndigits);
}
+EXPORT_SYMBOL(ecc_is_key_valid);

/*
* ECC private keys are generated using the method of extra random bits,
@@ -1000,6 +1006,7 @@ int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey)

return 0;
}
+EXPORT_SYMBOL(ecc_gen_privkey);

int ecc_make_pub_key(unsigned int curve_id, unsigned int ndigits,
const u64 *private_key, u64 *public_key)
@@ -1036,10 +1043,11 @@ int ecc_make_pub_key(unsigned int curve_id, unsigned int ndigits,
out:
return ret;
}
+EXPORT_SYMBOL(ecc_make_pub_key);

/* SP800-56A section 5.6.2.3.4 partial verification: ephemeral keys only */
-static int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
- struct ecc_point *pk)
+int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
+ struct ecc_point *pk)
{
u64 yy[ECC_MAX_DIGITS], xxx[ECC_MAX_DIGITS], w[ECC_MAX_DIGITS];

@@ -1064,8 +1072,8 @@ static int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
return -EINVAL;

return 0;
-
}
+EXPORT_SYMBOL(ecc_is_pubkey_valid_partial);

int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
const u64 *private_key, const u64 *public_key,
@@ -1121,3 +1129,6 @@ int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
out:
return ret;
}
+EXPORT_SYMBOL(crypto_ecdh_shared_secret);
+
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/crypto/ecc.h b/crypto/ecc.h
index f75a86baa3bd..3809dbeb699a 100644
--- a/crypto/ecc.h
+++ b/crypto/ecc.h
@@ -33,6 +33,41 @@
#define ECC_DIGITS_TO_BYTES_SHIFT 3

/**
+ * struct ecc_point - elliptic curve point in affine coordinates
+ *
+ * @x: X coordinate in vli form.
+ * @y: Y coordinate in vli form.
+ * @ndigits: Length of vlis in u64 qwords.
+ */
+struct ecc_point {
+ u64 *x;
+ u64 *y;
+ u8 ndigits;
+};
+
+/**
+ * struct ecc_curve - definition of elliptic curve
+ *
+ * @name: Short name of the curve.
+ * @g: Generator point of the curve.
+ * @p: Prime number, if Barrett's reduction is used for this curve
+ * pre-calculated value 'mu' is appended to the @p after ndigits.
+ * Use of Barrett's reduction is heuristically determined in
+ * vli_mmod_fast().
+ * @n: Order of the curve group.
+ * @a: Curve parameter a.
+ * @b: Curve parameter b.
+ */
+struct ecc_curve {
+ char *name;
+ struct ecc_point g;
+ u64 *p;
+ u64 *n;
+ u64 *a;
+ u64 *b;
+};
+
+/**
* ecc_is_key_valid() - Validate a given ECDH private key
*
* @curve_id: id representing the curve to use
@@ -91,4 +126,68 @@ int ecc_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
const u64 *private_key, const u64 *public_key,
u64 *secret);
+
+/**
+ * ecc_is_pubkey_valid_partial() - Partial public key validation
+ *
+ * @curve: elliptic curve domain parameters
+ * @pk: public key as a point
+ *
+ * Valdiate public key according to SP800-56A section 5.6.2.3.4 ECC Partial
+ * Public-Key Validation Routine.
+ *
+ * Note: There is no check that the public key is in the correct elliptic curve
+ * subgroup.
+ *
+ * Return: 0 if validation is successful, -EINVAL if validation is failed.
+ */
+int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
+ struct ecc_point *pk);
+
+/**
+ * vli_is_zero() - Determine is vli is zero
+ *
+ * @vli: vli to check.
+ * @ndigits: length of the @vli
+ */
+bool vli_is_zero(const u64 *vli, unsigned int ndigits);
+
+/**
+ * vli_cmp() - compare left and right vlis
+ *
+ * @left: vli
+ * @right: vli
+ * @ndigits: length of both vlis
+ *
+ * Returns sign of @left - @right, i.e. -1 if @left < @right,
+ * 0 if @left == @right, 1 if @left > @right.
+ */
+int vli_cmp(const u64 *left, const u64 *right, unsigned int ndigits);
+
+/**
+ * vli_sub() - Subtracts right from left
+ *
+ * @result: where to write result
+ * @left: vli
+ * @right vli
+ * @ndigits: length of all vlis
+ *
+ * Note: can modify in-place.
+ *
+ * Return: carry bit.
+ */
+u64 vli_sub(u64 *result, const u64 *left, const u64 *right,
+ unsigned int ndigits);
+
+/**
+ * vli_mod_inv() - Modular inversion
+ *
+ * @result: where to write vli number
+ * @input: vli value to operate on
+ * @mod: modulus
+ * @ndigits: length of all vlis
+ */
+void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod,
+ unsigned int ndigits);
+
#endif
diff --git a/crypto/ecc_curve_defs.h b/crypto/ecc_curve_defs.h
index 336ab1805639..69be6c7d228f 100644
--- a/crypto/ecc_curve_defs.h
+++ b/crypto/ecc_curve_defs.h
@@ -2,21 +2,6 @@
#ifndef _CRYTO_ECC_CURVE_DEFS_H
#define _CRYTO_ECC_CURVE_DEFS_H

-struct ecc_point {
- u64 *x;
- u64 *y;
- u8 ndigits;
-};
-
-struct ecc_curve {
- char *name;
- struct ecc_point g;
- u64 *p;
- u64 *n;
- u64 *a;
- u64 *b;
-};
-
/* NIST P-192: a = p - 3 */
static u64 nist_p192_g_x[] = { 0xF4FF0AFD82FF1012ull, 0x7CBF20EB43A18800ull,
0x188DA80EB03090F6ull };
--
2.11.0