Commit f9ed236c authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'for-upstream' of... 

Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next



Johan Hedberg says:

====================
pull request: bluetooth-next 2017-04-30

Here's one last batch of Bluetooth patches in the bluetooth-next tree
targeting the 4.12 kernel.

 - Remove custom ECDH implementation and use new KPP API instead
 - Add protocol checks to hci_ldisc
 - Add module license to HCI UART Nokia H4+ driver
 - Minor fix for 32bit user space - 64 bit kernel combination

Please let me know if there are any issues pulling. Thanks.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents d5066c46 71653eb6

drivers/bluetooth/hci_ldisc.c

+11 −3
Original line number Diff line number Diff line
@@ -113,16 +113,21 @@ static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu) 
{

	struct sk_buff *skb = hu->tx_skb;



	if (!skb)

	if (!skb) {

		if (test_bit(HCI_UART_PROTO_READY, &hu->flags))

			skb = hu->proto->dequeue(hu);

	else

	} else {

		hu->tx_skb = NULL;

	}



	return skb;

}



int hci_uart_tx_wakeup(struct hci_uart *hu)

{

	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))

		return 0;



	if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {

		set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);

		return 0;
@@ -256,6 +261,9 @@ static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb) 
	BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),

	       skb->len);



	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))

		return -EUNATCH;



	hu->proto->enqueue(hu, skb);



	hci_uart_tx_wakeup(hu);

drivers/bluetooth/hci_nokia.c

+7 −0
Original line number Diff line number Diff line
@@ -36,6 +36,8 @@ 
#include "hci_uart.h"

#include "btbcm.h"



#define VERSION "0.1"



#define NOKIA_ID_BCM2048	0x04

#define NOKIA_ID_TI1271		0x31
@@ -818,3 +820,8 @@ static struct serdev_device_driver nokia_bluetooth_serdev_driver = { 
};



module_serdev_device_driver(nokia_bluetooth_serdev_driver);



MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");

MODULE_DESCRIPTION("Bluetooth HCI UART Nokia H4+ driver ver " VERSION);

MODULE_VERSION(VERSION);

MODULE_LICENSE("GPL");

net/bluetooth/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ menuconfig BT 
	select CRYPTO_CMAC

	select CRYPTO_ECB

	select CRYPTO_SHA256

	select CRYPTO_ECDH

	help

	  Bluetooth is low-cost, low-power, short-range wireless technology.

	  It was designed as a replacement for cables and other short-range

net/bluetooth/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ bluetooth_6lowpan-y := 6lowpan.o 


bluetooth-y := af_bluetooth.o hci_core.o hci_conn.o hci_event.o mgmt.o \

	hci_sock.o hci_sysfs.o l2cap_core.o l2cap_sock.o smp.o lib.o \

	ecc.o hci_request.o mgmt_util.o

	ecdh_helper.o hci_request.o mgmt_util.o



bluetooth-$(CONFIG_BT_BREDR) += sco.o

bluetooth-$(CONFIG_BT_HS) += a2mp.o amp.o

net/bluetooth/ecc.c

deleted100644 → 0
+0 −816
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2013, Kenneth MacKay

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are

 * met:

 *  * Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 *  * Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */



#include <linux/random.h>



#include "ecc.h"



/* 256-bit curve */

#define ECC_BYTES 32



#define MAX_TRIES 16



/* Number of u64's needed */

#define NUM_ECC_DIGITS (ECC_BYTES / 8)



struct ecc_point {

	u64 x[NUM_ECC_DIGITS];

	u64 y[NUM_ECC_DIGITS];

};



typedef struct {

	u64 m_low;

	u64 m_high;

} uint128_t;



#define CURVE_P_32 {	0xFFFFFFFFFFFFFFFFull, 0x00000000FFFFFFFFull, \

			0x0000000000000000ull, 0xFFFFFFFF00000001ull }



#define CURVE_G_32 { \

		{	0xF4A13945D898C296ull, 0x77037D812DEB33A0ull,	\

			0xF8BCE6E563A440F2ull, 0x6B17D1F2E12C4247ull }, \

		{	0xCBB6406837BF51F5ull, 0x2BCE33576B315ECEull,	\

			0x8EE7EB4A7C0F9E16ull, 0x4FE342E2FE1A7F9Bull }	\

}



#define CURVE_N_32 {	0xF3B9CAC2FC632551ull, 0xBCE6FAADA7179E84ull,	\

			0xFFFFFFFFFFFFFFFFull, 0xFFFFFFFF00000000ull }



static u64 curve_p[NUM_ECC_DIGITS] = CURVE_P_32;

static struct ecc_point curve_g = CURVE_G_32;

static u64 curve_n[NUM_ECC_DIGITS] = CURVE_N_32;



static void vli_clear(u64 *vli)

{

	int i;



	for (i = 0; i < NUM_ECC_DIGITS; i++)

		vli[i] = 0;

}



/* Returns true if vli == 0, false otherwise. */

static bool vli_is_zero(const u64 *vli)

{

	int i;



	for (i = 0; i < NUM_ECC_DIGITS; i++) {

		if (vli[i])

			return false;

	}



	return true;

}



/* Returns nonzero if bit bit of vli is set. */

static u64 vli_test_bit(const u64 *vli, unsigned int bit)

{

	return (vli[bit / 64] & ((u64) 1 << (bit % 64)));

}



/* Counts the number of 64-bit "digits" in vli. */

static unsigned int vli_num_digits(const u64 *vli)

{

	int i;



	/* Search from the end until we find a non-zero digit.

	 * We do it in reverse because we expect that most digits will

	 * be nonzero.

	 */

	for (i = NUM_ECC_DIGITS - 1; i >= 0 && vli[i] == 0; i--);



	return (i + 1);

}



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

static unsigned int vli_num_bits(const u64 *vli)

{

	unsigned int i, num_digits;

	u64 digit;



	num_digits = vli_num_digits(vli);

	if (num_digits == 0)

		return 0;



	digit = vli[num_digits - 1];

	for (i = 0; digit; i++)

		digit >>= 1;



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

}



/* Sets dest = src. */

static void vli_set(u64 *dest, const u64 *src)

{

	int i;



	for (i = 0; i < NUM_ECC_DIGITS; i++)

		dest[i] = src[i];

}



/* Returns sign of left - right. */

static int vli_cmp(const u64 *left, const u64 *right)

{

    int i;



    for (i = NUM_ECC_DIGITS - 1; i >= 0; i--) {

	    if (left[i] > right[i])

		    return 1;

	    else if (left[i] < right[i])

		    return -1;

    }



    return 0;

}



/* Computes result = in << c, returning carry. Can modify in place

 * (if result == in). 0 < shift < 64.

 */

static u64 vli_lshift(u64 *result, const u64 *in,

			   unsigned int shift)

{

	u64 carry = 0;

	int i;



	for (i = 0; i < NUM_ECC_DIGITS; i++) {

		u64 temp = in[i];



		result[i] = (temp << shift) | carry;

		carry = temp >> (64 - shift);

	}



	return carry;

}



/* Computes vli = vli >> 1. */

static void vli_rshift1(u64 *vli)

{

	u64 *end = vli;

	u64 carry = 0;



	vli += NUM_ECC_DIGITS;



	while (vli-- > end) {

		u64 temp = *vli;

		*vli = (temp >> 1) | carry;

		carry = temp << 63;

	}

}



/* Computes result = left + right, returning carry. Can modify in place. */

static u64 vli_add(u64 *result, const u64 *left,

			const u64 *right)

{

	u64 carry = 0;

	int i;



	for (i = 0; i < NUM_ECC_DIGITS; i++) {

		u64 sum;



		sum = left[i] + right[i] + carry;

		if (sum != left[i])

			carry = (sum < left[i]);



		result[i] = sum;

	}



	return carry;

}



/* Computes result = left - right, returning borrow. Can modify in place. */

static u64 vli_sub(u64 *result, const u64 *left, const u64 *right)

{

	u64 borrow = 0;

	int i;



	for (i = 0; i < NUM_ECC_DIGITS; i++) {

		u64 diff;



		diff = left[i] - right[i] - borrow;

		if (diff != left[i])

			borrow = (diff > left[i]);



		result[i] = diff;

	}



	return borrow;

}



static uint128_t mul_64_64(u64 left, u64 right)

{

	u64 a0 = left & 0xffffffffull;

	u64 a1 = left >> 32;

	u64 b0 = right & 0xffffffffull;

	u64 b1 = right >> 32;

	u64 m0 = a0 * b0;

	u64 m1 = a0 * b1;

	u64 m2 = a1 * b0;

	u64 m3 = a1 * b1;

	uint128_t result;



	m2 += (m0 >> 32);

	m2 += m1;



	/* Overflow */

	if (m2 < m1)

		m3 += 0x100000000ull;



	result.m_low = (m0 & 0xffffffffull) | (m2 << 32);

	result.m_high = m3 + (m2 >> 32);



	return result;

}



static uint128_t add_128_128(uint128_t a, uint128_t b)

{

	uint128_t result;



	result.m_low = a.m_low + b.m_low;

	result.m_high = a.m_high + b.m_high + (result.m_low < a.m_low);



	return result;

}



static void vli_mult(u64 *result, const u64 *left, const u64 *right)

{

	uint128_t r01 = { 0, 0 };

	u64 r2 = 0;

	unsigned int i, k;



	/* Compute each digit of result in sequence, maintaining the

	 * carries.

	 */

	for (k = 0; k < NUM_ECC_DIGITS * 2 - 1; k++) {

		unsigned int min;



		if (k < NUM_ECC_DIGITS)

			min = 0;

		else

			min = (k + 1) - NUM_ECC_DIGITS;



		for (i = min; i <= k && i < NUM_ECC_DIGITS; i++) {

			uint128_t product;



			product = mul_64_64(left[i], right[k - i]);



			r01 = add_128_128(r01, product);

			r2 += (r01.m_high < product.m_high);

		}



		result[k] = r01.m_low;

		r01.m_low = r01.m_high;

		r01.m_high = r2;

		r2 = 0;

	}



	result[NUM_ECC_DIGITS * 2 - 1] = r01.m_low;

}



static void vli_square(u64 *result, const u64 *left)

{

	uint128_t r01 = { 0, 0 };

	u64 r2 = 0;

	int i, k;



	for (k = 0; k < NUM_ECC_DIGITS * 2 - 1; k++) {

		unsigned int min;



		if (k < NUM_ECC_DIGITS)

			min = 0;

		else

			min = (k + 1) - NUM_ECC_DIGITS;



		for (i = min; i <= k && i <= k - i; i++) {

			uint128_t product;



			product = mul_64_64(left[i], left[k - i]);



			if (i < k - i) {

				r2 += product.m_high >> 63;

				product.m_high = (product.m_high << 1) |

						 (product.m_low >> 63);

				product.m_low <<= 1;

			}



			r01 = add_128_128(r01, product);

			r2 += (r01.m_high < product.m_high);

		}



		result[k] = r01.m_low;

		r01.m_low = r01.m_high;

		r01.m_high = r2;

		r2 = 0;

	}



	result[NUM_ECC_DIGITS * 2 - 1] = r01.m_low;

}



/* Computes result = (left + right) % mod.

 * Assumes that left < mod and right < mod, result != mod.

 */

static void vli_mod_add(u64 *result, const u64 *left, const u64 *right,

			const u64 *mod)

{

	u64 carry;



	carry = vli_add(result, left, right);



	/* result > mod (result = mod + remainder), so subtract mod to

	 * get remainder.

	 */

	if (carry || vli_cmp(result, mod) >= 0)

		vli_sub(result, result, mod);

}



/* Computes result = (left - right) % mod.

 * Assumes that left < mod and right < mod, result != mod.

 */

static void vli_mod_sub(u64 *result, const u64 *left, const u64 *right,

			const u64 *mod)

{

	u64 borrow = vli_sub(result, left, right);



	/* In this case, p_result == -diff == (max int) - diff.

	 * Since -x % d == d - x, we can get the correct result from

	 * result + mod (with overflow).

	 */

	if (borrow)

		vli_add(result, result, mod);

}



/* Computes result = product % curve_p

   from http://www.nsa.gov/ia/_files/nist-routines.pdf */

static void vli_mmod_fast(u64 *result, const u64 *product)

{

	u64 tmp[NUM_ECC_DIGITS];

	int carry;



	/* t */

	vli_set(result, product);



	/* s1 */

	tmp[0] = 0;

	tmp[1] = product[5] & 0xffffffff00000000ull;

	tmp[2] = product[6];

	tmp[3] = product[7];

	carry = vli_lshift(tmp, tmp, 1);

	carry += vli_add(result, result, tmp);



	/* s2 */

	tmp[1] = product[6] << 32;

	tmp[2] = (product[6] >> 32) | (product[7] << 32);

	tmp[3] = product[7] >> 32;

	carry += vli_lshift(tmp, tmp, 1);

	carry += vli_add(result, result, tmp);



	/* s3 */

	tmp[0] = product[4];

	tmp[1] = product[5] & 0xffffffff;

	tmp[2] = 0;

	tmp[3] = product[7];

	carry += vli_add(result, result, tmp);



	/* s4 */

	tmp[0] = (product[4] >> 32) | (product[5] << 32);

	tmp[1] = (product[5] >> 32) | (product[6] & 0xffffffff00000000ull);

	tmp[2] = product[7];

	tmp[3] = (product[6] >> 32) | (product[4] << 32);

	carry += vli_add(result, result, tmp);



	/* d1 */

	tmp[0] = (product[5] >> 32) | (product[6] << 32);

	tmp[1] = (product[6] >> 32);

	tmp[2] = 0;

	tmp[3] = (product[4] & 0xffffffff) | (product[5] << 32);

	carry -= vli_sub(result, result, tmp);



	/* d2 */

	tmp[0] = product[6];

	tmp[1] = product[7];

	tmp[2] = 0;

	tmp[3] = (product[4] >> 32) | (product[5] & 0xffffffff00000000ull);

	carry -= vli_sub(result, result, tmp);



	/* d3 */

	tmp[0] = (product[6] >> 32) | (product[7] << 32);

	tmp[1] = (product[7] >> 32) | (product[4] << 32);

	tmp[2] = (product[4] >> 32) | (product[5] << 32);

	tmp[3] = (product[6] << 32);

	carry -= vli_sub(result, result, tmp);



	/* d4 */

	tmp[0] = product[7];

	tmp[1] = product[4] & 0xffffffff00000000ull;

	tmp[2] = product[5];

	tmp[3] = product[6] & 0xffffffff00000000ull;

	carry -= vli_sub(result, result, tmp);



	if (carry < 0) {

		do {

			carry += vli_add(result, result, curve_p);

		} while (carry < 0);

	} else {

		while (carry || vli_cmp(curve_p, result) != 1)

			carry -= vli_sub(result, result, curve_p);

	}

}



/* Computes result = (left * right) % curve_p. */

static void vli_mod_mult_fast(u64 *result, const u64 *left, const u64 *right)

{

	u64 product[2 * NUM_ECC_DIGITS];



	vli_mult(product, left, right);

	vli_mmod_fast(result, product);

}



/* Computes result = left^2 % curve_p. */

static void vli_mod_square_fast(u64 *result, const u64 *left)

{

	u64 product[2 * NUM_ECC_DIGITS];



	vli_square(product, left);

	vli_mmod_fast(result, product);

}



#define EVEN(vli) (!(vli[0] & 1))

/* Computes result = (1 / p_input) % mod. All VLIs are the same size.

 * 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)

{

	u64 a[NUM_ECC_DIGITS], b[NUM_ECC_DIGITS];

	u64 u[NUM_ECC_DIGITS], v[NUM_ECC_DIGITS];

	u64 carry;

	int cmp_result;



	if (vli_is_zero(input)) {

		vli_clear(result);

		return;

	}



	vli_set(a, input);

	vli_set(b, mod);

	vli_clear(u);

	u[0] = 1;

	vli_clear(v);



	while ((cmp_result = vli_cmp(a, b)) != 0) {

		carry = 0;



		if (EVEN(a)) {

			vli_rshift1(a);



			if (!EVEN(u))

				carry = vli_add(u, u, mod);



			vli_rshift1(u);

			if (carry)

				u[NUM_ECC_DIGITS - 1] |= 0x8000000000000000ull;

		} else if (EVEN(b)) {

			vli_rshift1(b);



			if (!EVEN(v))

				carry = vli_add(v, v, mod);



			vli_rshift1(v);

			if (carry)

				v[NUM_ECC_DIGITS - 1] |= 0x8000000000000000ull;

		} else if (cmp_result > 0) {

			vli_sub(a, a, b);

			vli_rshift1(a);



			if (vli_cmp(u, v) < 0)

				vli_add(u, u, mod);



			vli_sub(u, u, v);

			if (!EVEN(u))

				carry = vli_add(u, u, mod);



			vli_rshift1(u);

			if (carry)

				u[NUM_ECC_DIGITS - 1] |= 0x8000000000000000ull;

		} else {

			vli_sub(b, b, a);

			vli_rshift1(b);



			if (vli_cmp(v, u) < 0)

				vli_add(v, v, mod);



			vli_sub(v, v, u);

			if (!EVEN(v))

				carry = vli_add(v, v, mod);



			vli_rshift1(v);

			if (carry)

				v[NUM_ECC_DIGITS - 1] |= 0x8000000000000000ull;

		}

	}



	vli_set(result, u);

}



/* ------ 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)

{

	return (vli_is_zero(point->x) && vli_is_zero(point->y));

}



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

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

 */



/* Double in place */

static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1)

{

	/* t1 = x, t2 = y, t3 = z */

	u64 t4[NUM_ECC_DIGITS];

	u64 t5[NUM_ECC_DIGITS];



	if (vli_is_zero(z1))

		return;



	vli_mod_square_fast(t4, y1);   /* t4 = y1^2 */

	vli_mod_mult_fast(t5, x1, t4); /* t5 = x1*y1^2 = A */

	vli_mod_square_fast(t4, t4);   /* t4 = y1^4 */

	vli_mod_mult_fast(y1, y1, z1); /* t2 = y1*z1 = z3 */

	vli_mod_square_fast(z1, z1);   /* t3 = z1^2 */



	vli_mod_add(x1, x1, z1, curve_p); /* t1 = x1 + z1^2 */

	vli_mod_add(z1, z1, z1, curve_p); /* t3 = 2*z1^2 */

	vli_mod_sub(z1, x1, z1, curve_p); /* t3 = x1 - z1^2 */

	vli_mod_mult_fast(x1, x1, z1);    /* t1 = x1^2 - z1^4 */



	vli_mod_add(z1, x1, x1, curve_p); /* t3 = 2*(x1^2 - z1^4) */

	vli_mod_add(x1, x1, z1, curve_p); /* t1 = 3*(x1^2 - z1^4) */

	if (vli_test_bit(x1, 0)) {

		u64 carry = vli_add(x1, x1, curve_p);

		vli_rshift1(x1);

		x1[NUM_ECC_DIGITS - 1] |= carry << 63;

	} else {

		vli_rshift1(x1);

	}

	/* t1 = 3/2*(x1^2 - z1^4) = B */



	vli_mod_square_fast(z1, x1);      /* t3 = B^2 */

	vli_mod_sub(z1, z1, t5, curve_p); /* t3 = B^2 - A */

	vli_mod_sub(z1, z1, t5, curve_p); /* t3 = B^2 - 2A = x3 */

	vli_mod_sub(t5, t5, z1, curve_p); /* t5 = A - x3 */

	vli_mod_mult_fast(x1, x1, t5);    /* t1 = B * (A - x3) */

	vli_mod_sub(t4, x1, t4, curve_p); /* t4 = B * (A - x3) - y1^4 = y3 */



	vli_set(x1, z1);

	vli_set(z1, y1);

	vli_set(y1, t4);

}



/* Modify (x1, y1) => (x1 * z^2, y1 * z^3) */

static void apply_z(u64 *x1, u64 *y1, u64 *z)

{

	u64 t1[NUM_ECC_DIGITS];



	vli_mod_square_fast(t1, z);    /* z^2 */

	vli_mod_mult_fast(x1, x1, t1); /* x1 * z^2 */

	vli_mod_mult_fast(t1, t1, z);  /* z^3 */

	vli_mod_mult_fast(y1, y1, t1); /* y1 * z^3 */

}



/* P = (x1, y1) => 2P, (x2, y2) => P' */

static void xycz_initial_double(u64 *x1, u64 *y1, u64 *x2, u64 *y2,

				u64 *p_initial_z)

{

	u64 z[NUM_ECC_DIGITS];



	vli_set(x2, x1);

	vli_set(y2, y1);



	vli_clear(z);

	z[0] = 1;



	if (p_initial_z)

		vli_set(z, p_initial_z);



	apply_z(x1, y1, z);



	ecc_point_double_jacobian(x1, y1, z);



	apply_z(x2, y2, z);

}



/* Input P = (x1, y1, Z), Q = (x2, y2, Z)

 * Output P' = (x1', y1', Z3), P + Q = (x3, y3, Z3)

 * or P => P', Q => P + Q

 */

static void xycz_add(u64 *x1, u64 *y1, u64 *x2, u64 *y2)

{

	/* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */

	u64 t5[NUM_ECC_DIGITS];



	vli_mod_sub(t5, x2, x1, curve_p); /* t5 = x2 - x1 */

	vli_mod_square_fast(t5, t5);      /* t5 = (x2 - x1)^2 = A */

	vli_mod_mult_fast(x1, x1, t5);    /* t1 = x1*A = B */

	vli_mod_mult_fast(x2, x2, t5);    /* t3 = x2*A = C */

	vli_mod_sub(y2, y2, y1, curve_p); /* t4 = y2 - y1 */

	vli_mod_square_fast(t5, y2);      /* t5 = (y2 - y1)^2 = D */



	vli_mod_sub(t5, t5, x1, curve_p); /* t5 = D - B */

	vli_mod_sub(t5, t5, x2, curve_p); /* t5 = D - B - C = x3 */

	vli_mod_sub(x2, x2, x1, curve_p); /* t3 = C - B */

	vli_mod_mult_fast(y1, y1, x2);    /* t2 = y1*(C - B) */

	vli_mod_sub(x2, x1, t5, curve_p); /* t3 = B - x3 */

	vli_mod_mult_fast(y2, y2, x2);    /* t4 = (y2 - y1)*(B - x3) */

	vli_mod_sub(y2, y2, y1, curve_p); /* t4 = y3 */



	vli_set(x2, t5);

}



/* Input P = (x1, y1, Z), Q = (x2, y2, Z)

 * Output P + Q = (x3, y3, Z3), P - Q = (x3', y3', Z3)

 * or P => P - Q, Q => P + Q

 */

static void xycz_add_c(u64 *x1, u64 *y1, u64 *x2, u64 *y2)

{

	/* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */

	u64 t5[NUM_ECC_DIGITS];

	u64 t6[NUM_ECC_DIGITS];

	u64 t7[NUM_ECC_DIGITS];



	vli_mod_sub(t5, x2, x1, curve_p); /* t5 = x2 - x1 */

	vli_mod_square_fast(t5, t5);      /* t5 = (x2 - x1)^2 = A */

	vli_mod_mult_fast(x1, x1, t5);    /* t1 = x1*A = B */

	vli_mod_mult_fast(x2, x2, t5);    /* t3 = x2*A = C */

	vli_mod_add(t5, y2, y1, curve_p); /* t4 = y2 + y1 */

	vli_mod_sub(y2, y2, y1, curve_p); /* t4 = y2 - y1 */



	vli_mod_sub(t6, x2, x1, curve_p); /* t6 = C - B */

	vli_mod_mult_fast(y1, y1, t6);    /* t2 = y1 * (C - B) */

	vli_mod_add(t6, x1, x2, curve_p); /* t6 = B + C */

	vli_mod_square_fast(x2, y2);      /* t3 = (y2 - y1)^2 */

	vli_mod_sub(x2, x2, t6, curve_p); /* t3 = x3 */



	vli_mod_sub(t7, x1, x2, curve_p); /* t7 = B - x3 */

	vli_mod_mult_fast(y2, y2, t7);    /* t4 = (y2 - y1)*(B - x3) */

	vli_mod_sub(y2, y2, y1, curve_p); /* t4 = y3 */



	vli_mod_square_fast(t7, t5);      /* t7 = (y2 + y1)^2 = F */

	vli_mod_sub(t7, t7, t6, curve_p); /* t7 = x3' */

	vli_mod_sub(t6, t7, x1, curve_p); /* t6 = x3' - B */

	vli_mod_mult_fast(t6, t6, t5);    /* t6 = (y2 + y1)*(x3' - B) */

	vli_mod_sub(y1, t6, y1, curve_p); /* t2 = y3' */



	vli_set(x1, t7);

}



static void ecc_point_mult(struct ecc_point *result,

			   const struct ecc_point *point, u64 *scalar,

			   u64 *initial_z, int num_bits)

{

	/* R0 and R1 */

	u64 rx[2][NUM_ECC_DIGITS];

	u64 ry[2][NUM_ECC_DIGITS];

	u64 z[NUM_ECC_DIGITS];

	int i, nb;



	vli_set(rx[1], point->x);

	vli_set(ry[1], point->y);



	xycz_initial_double(rx[1], ry[1], rx[0], ry[0], initial_z);



	for (i = num_bits - 2; i > 0; i--) {

		nb = !vli_test_bit(scalar, i);

		xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb]);

		xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb]);

	}



	nb = !vli_test_bit(scalar, 0);

	xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb]);



	/* Find final 1/Z value. */

	vli_mod_sub(z, rx[1], rx[0], curve_p); /* X1 - X0 */

	vli_mod_mult_fast(z, z, ry[1 - nb]); /* Yb * (X1 - X0) */

	vli_mod_mult_fast(z, z, point->x);   /* xP * Yb * (X1 - X0) */

	vli_mod_inv(z, z, curve_p);          /* 1 / (xP * Yb * (X1 - X0)) */

	vli_mod_mult_fast(z, z, point->y);   /* yP / (xP * Yb * (X1 - X0)) */

	vli_mod_mult_fast(z, z, rx[1 - nb]); /* Xb * yP / (xP * Yb * (X1 - X0)) */

	/* End 1/Z calculation */



	xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb]);



	apply_z(rx[0], ry[0], z);



	vli_set(result->x, rx[0]);

	vli_set(result->y, ry[0]);

}



static void ecc_bytes2native(const u8 bytes[ECC_BYTES],

			     u64 native[NUM_ECC_DIGITS])

{

	int i;



	for (i = 0; i < NUM_ECC_DIGITS; i++) {

		const u8 *digit = bytes + 8 * (NUM_ECC_DIGITS - 1 - i);



		native[NUM_ECC_DIGITS - 1 - i] =

				((u64) digit[0] << 0) |

				((u64) digit[1] << 8) |

				((u64) digit[2] << 16) |

				((u64) digit[3] << 24) |

				((u64) digit[4] << 32) |

				((u64) digit[5] << 40) |

				((u64) digit[6] << 48) |

				((u64) digit[7] << 56);

	}

}



static void ecc_native2bytes(const u64 native[NUM_ECC_DIGITS],

			     u8 bytes[ECC_BYTES])

{

	int i;



	for (i = 0; i < NUM_ECC_DIGITS; i++) {

		u8 *digit = bytes + 8 * (NUM_ECC_DIGITS - 1 - i);



		digit[0] = native[NUM_ECC_DIGITS - 1 - i] >> 0;

		digit[1] = native[NUM_ECC_DIGITS - 1 - i] >> 8;

		digit[2] = native[NUM_ECC_DIGITS - 1 - i] >> 16;

		digit[3] = native[NUM_ECC_DIGITS - 1 - i] >> 24;

		digit[4] = native[NUM_ECC_DIGITS - 1 - i] >> 32;

		digit[5] = native[NUM_ECC_DIGITS - 1 - i] >> 40;

		digit[6] = native[NUM_ECC_DIGITS - 1 - i] >> 48;

		digit[7] = native[NUM_ECC_DIGITS - 1 - i] >> 56;

	}

}



bool ecc_make_key(u8 public_key[64], u8 private_key[32])

{

	struct ecc_point pk;

	u64 priv[NUM_ECC_DIGITS];

	unsigned int tries = 0;



	do {

		if (tries++ >= MAX_TRIES)

			return false;



		get_random_bytes(priv, ECC_BYTES);



		if (vli_is_zero(priv))

			continue;



		/* Make sure the private key is in the range [1, n-1]. */

		if (vli_cmp(curve_n, priv) != 1)

			continue;



		ecc_point_mult(&pk, &curve_g, priv, NULL, vli_num_bits(priv));

	} while (ecc_point_is_zero(&pk));



	ecc_native2bytes(priv, private_key);

	ecc_native2bytes(pk.x, public_key);

	ecc_native2bytes(pk.y, &public_key[32]);



	return true;

}



bool ecdh_shared_secret(const u8 public_key[64], const u8 private_key[32],

		        u8 secret[32])

{

	u64 priv[NUM_ECC_DIGITS];

	u64 rand[NUM_ECC_DIGITS];

	struct ecc_point product, pk;



	get_random_bytes(rand, ECC_BYTES);



	ecc_bytes2native(public_key, pk.x);

	ecc_bytes2native(&public_key[32], pk.y);

	ecc_bytes2native(private_key, priv);



	ecc_point_mult(&product, &pk, priv, rand, vli_num_bits(priv));



	ecc_native2bytes(product.x, secret);



	return !ecc_point_is_zero(&product);

}

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