1 files changed, 726 insertions, 130 deletions

diff --git a/crypto/ecc.c b/crypto/ecc.c
index ed1237115066..6cf9a945fc6c 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 2013, Kenneth MacKay
- * All rights reserved.
+ * Copyright (c) 2013, 2014 Kenneth MacKay. All rights reserved.
+ * Copyright (c) 2019 Vitaly Chikunov <vt@altlinux.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -24,14 +24,18 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <crypto/ecc_curve.h>
+#include <linux/module.h>
 #include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/swab.h>
 #include <linux/fips.h>
 #include <crypto/ecdh.h>
 #include <crypto/rng.h>
+#include <crypto/internal/ecc.h>
+#include <linux/unaligned.h>
+#include <linux/ratelimit.h>
 
-#include "ecc.h"
 #include "ecc_curve_defs.h"
 
 typedef struct {
@@ -39,7 +43,14 @@ typedef struct {
 	u64 m_high;
 } uint128_t;
 
-static inline const struct ecc_curve *ecc_get_curve(unsigned int curve_id)
+/* Returns curv25519 curve param */
+const struct ecc_curve *ecc_get_curve25519(void)
+{
+	return &ecc_25519;
+}
+EXPORT_SYMBOL(ecc_get_curve25519);
+
+const struct ecc_curve *ecc_get_curve(unsigned int curve_id)
 {
 	switch (curve_id) {
 	/* In FIPS mode only allow P256 and higher */
@@ -47,10 +58,37 @@ static inline const struct ecc_curve *ecc_get_curve(unsigned int curve_id)
 		return fips_enabled ? NULL : &nist_p192;
 	case ECC_CURVE_NIST_P256:
 		return &nist_p256;
+	case ECC_CURVE_NIST_P384:
+		return &nist_p384;
+	case ECC_CURVE_NIST_P521:
+		return &nist_p521;
 	default:
 		return NULL;
 	}
 }
+EXPORT_SYMBOL(ecc_get_curve);
+
+void ecc_digits_from_bytes(const u8 *in, unsigned int nbytes,
+			   u64 *out, unsigned int ndigits)
+{
+	int diff = ndigits - DIV_ROUND_UP_POW2(nbytes, sizeof(u64));
+	unsigned int o = nbytes & 7;
+	__be64 msd = 0;
+
+	/* diff > 0: not enough input bytes: set most significant digits to 0 */
+	if (diff > 0) {
+		ndigits -= diff;
+		memset(&out[ndigits], 0, diff * sizeof(u64));
+	}
+
+	if (o) {
+		memcpy((u8 *)&msd + sizeof(msd) - o, in, o);
+		out[--ndigits] = be64_to_cpu(msd);
+		in += o;
+	}
+	ecc_swap_digits(in, out, ndigits);
+}
+EXPORT_SYMBOL(ecc_digits_from_bytes);
 
 static u64 *ecc_alloc_digits_space(unsigned int ndigits)
 {
@@ -64,10 +102,10 @@ static u64 *ecc_alloc_digits_space(unsigned int ndigits)
 
 static void ecc_free_digits_space(u64 *space)
 {
-	kzfree(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);
 
@@ -92,16 +130,18 @@ err_alloc_x:
 	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;
 
-	kzfree(p->x);
-	kzfree(p->y);
-	kzfree(p);
+	kfree_sensitive(p->x);
+	kfree_sensitive(p->y);
+	kfree_sensitive(p);
 }
+EXPORT_SYMBOL(ecc_free_point);
 
 static void vli_clear(u64 *vli, unsigned int ndigits)
 {
@@ -112,7 +152,7 @@ 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;
 
@@ -123,13 +163,19 @@ 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. */
+/* Returns nonzero if bit of vli is set. */
 static u64 vli_test_bit(const u64 *vli, unsigned int bit)
 {
 	return (vli[bit / 64] & ((u64)1 << (bit % 64)));
 }
 
+static bool vli_is_negative(const u64 *vli, unsigned int ndigits)
+{
+	return vli_test_bit(vli, ndigits * 64 - 1);
+}
+
 /* Counts the number of 64-bit "digits" in vli. */
 static unsigned int vli_num_digits(const u64 *vli, unsigned int ndigits)
 {
@@ -145,7 +191,7 @@ 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;
@@ -160,6 +206,28 @@ 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)
+{
+	int i;
+	const u64 *from = src;
+
+	for (i = 0; i < ndigits; i++)
+		dest[i] = get_unaligned_be64(&from[ndigits - 1 - i]);
+}
+EXPORT_SYMBOL(vli_from_be64);
+
+void vli_from_le64(u64 *dest, const void *src, unsigned int ndigits)
+{
+	int i;
+	const u64 *from = src;
+
+	for (i = 0; i < ndigits; i++)
+		dest[i] = get_unaligned_le64(&from[i]);
+}
+EXPORT_SYMBOL(vli_from_le64);
 
 /* Sets dest = src. */
 static void vli_set(u64 *dest, const u64 *src, unsigned int ndigits)
@@ -171,7 +239,7 @@ 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 +252,7 @@ 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.
@@ -239,8 +308,30 @@ static u64 vli_add(u64 *result, const u64 *left, const u64 *right,
 	return carry;
 }
 
+/* Computes result = left + right, returning carry. Can modify in place. */
+static u64 vli_uadd(u64 *result, const u64 *left, u64 right,
+		    unsigned int ndigits)
+{
+	u64 carry = right;
+	int i;
+
+	for (i = 0; i < ndigits; i++) {
+		u64 sum;
+
+		sum = left[i] + carry;
+		if (sum != left[i])
+			carry = (sum < left[i]);
+		else
+			carry = !!carry;
+
+		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 vli_sub(u64 *result, const u64 *left, const u64 *right,
 		   unsigned int ndigits)
 {
 	u64 borrow = 0;
@@ -258,9 +349,37 @@ static u64 vli_sub(u64 *result, const u64 *left, const u64 *right,
 
 	return borrow;
 }
+EXPORT_SYMBOL(vli_sub);
+
+/* Computes result = left - right, returning borrow. Can modify in place. */
+static u64 vli_usub(u64 *result, const u64 *left, u64 right,
+	     unsigned int ndigits)
+{
+	u64 borrow = right;
+	int i;
+
+	for (i = 0; i < ndigits; i++) {
+		u64 diff;
+
+		diff = left[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)
 {
+	uint128_t result;
+#if defined(CONFIG_ARCH_SUPPORTS_INT128)
+	unsigned __int128 m = (unsigned __int128)left * right;
+
+	result.m_low  = m;
+	result.m_high = m >> 64;
+#else
 	u64 a0 = left & 0xffffffffull;
 	u64 a1 = left >> 32;
 	u64 b0 = right & 0xffffffffull;
@@ -269,7 +388,6 @@ static uint128_t mul_64_64(u64 left, u64 right)
 	u64 m1 = a0 * b1;
 	u64 m2 = a1 * b0;
 	u64 m3 = a1 * b1;
-	uint128_t result;
 
 	m2 += (m0 >> 32);
 	m2 += m1;
@@ -280,7 +398,7 @@ static uint128_t mul_64_64(u64 left, u64 right)
 
 	result.m_low = (m0 & 0xffffffffull) | (m2 << 32);
 	result.m_high = m3 + (m2 >> 32);
-
+#endif
 	return result;
 }
 
@@ -330,6 +448,28 @@ static void vli_mult(u64 *result, const u64 *left, const u64 *right,
 	result[ndigits * 2 - 1] = r01.m_low;
 }
 
+/* Compute product = left * right, for a small right value. */
+static void vli_umult(u64 *result, const u64 *left, u32 right,
+		      unsigned int ndigits)
+{
+	uint128_t r01 = { 0 };
+	unsigned int k;
+
+	for (k = 0; k < ndigits; k++) {
+		uint128_t product;
+
+		product = mul_64_64(left[k], right);
+		r01 = add_128_128(r01, product);
+		/* no carry */
+		result[k] = r01.m_low;
+		r01.m_low = r01.m_high;
+		r01.m_high = 0;
+	}
+	result[k] = r01.m_low;
+	for (++k; k < ndigits * 2; k++)
+		result[k] = 0;
+}
+
 static void vli_square(u64 *result, const u64 *left, unsigned int ndigits)
 {
 	uint128_t r01 = { 0, 0 };
@@ -402,6 +542,170 @@ static void vli_mod_sub(u64 *result, const u64 *left, const u64 *right,
 		vli_add(result, result, mod, ndigits);
 }
 
+/*
+ * Computes result = product % mod
+ * for special form moduli: p = 2^k-c, for small c (note the minus sign)
+ *
+ * References:
+ * R. Crandall, C. Pomerance. Prime Numbers: A Computational Perspective.
+ * 9 Fast Algorithms for Large-Integer Arithmetic. 9.2.3 Moduli of special form
+ * Algorithm 9.2.13 (Fast mod operation for special-form moduli).
+ */
+static void vli_mmod_special(u64 *result, const u64 *product,
+			      const u64 *mod, unsigned int ndigits)
+{
+	u64 c = -mod[0];
+	u64 t[ECC_MAX_DIGITS * 2];
+	u64 r[ECC_MAX_DIGITS * 2];
+
+	vli_set(r, product, ndigits * 2);
+	while (!vli_is_zero(r + ndigits, ndigits)) {
+		vli_umult(t, r + ndigits, c, ndigits);
+		vli_clear(r + ndigits, ndigits);
+		vli_add(r, r, t, ndigits * 2);
+	}
+	vli_set(t, mod, ndigits);
+	vli_clear(t + ndigits, ndigits);
+	while (vli_cmp(r, t, ndigits * 2) >= 0)
+		vli_sub(r, r, t, ndigits * 2);
+	vli_set(result, r, ndigits);
+}
+
+/*
+ * Computes result = product % mod
+ * for special form moduli: p = 2^{k-1}+c, for small c (note the plus sign)
+ * where k-1 does not fit into qword boundary by -1 bit (such as 255).
+
+ * References (loosely based on):
+ * A. Menezes, P. van Oorschot, S. Vanstone. Handbook of Applied Cryptography.
+ * 14.3.4 Reduction methods for moduli of special form. Algorithm 14.47.
+ * URL: http://cacr.uwaterloo.ca/hac/about/chap14.pdf
+ *
+ * H. Cohen, G. Frey, R. Avanzi, C. Doche, T. Lange, K. Nguyen, F. Vercauteren.
+ * Handbook of Elliptic and Hyperelliptic Curve Cryptography.
+ * Algorithm 10.25 Fast reduction for special form moduli
+ */
+static void vli_mmod_special2(u64 *result, const u64 *product,
+			       const u64 *mod, unsigned int ndigits)
+{
+	u64 c2 = mod[0] * 2;
+	u64 q[ECC_MAX_DIGITS];
+	u64 r[ECC_MAX_DIGITS * 2];
+	u64 m[ECC_MAX_DIGITS * 2]; /* expanded mod */
+	int carry; /* last bit that doesn't fit into q */
+	int i;
+
+	vli_set(m, mod, ndigits);
+	vli_clear(m + ndigits, ndigits);
+
+	vli_set(r, product, ndigits);
+	/* q and carry are top bits */
+	vli_set(q, product + ndigits, ndigits);
+	vli_clear(r + ndigits, ndigits);
+	carry = vli_is_negative(r, ndigits);
+	if (carry)
+		r[ndigits - 1] &= (1ull << 63) - 1;
+	for (i = 1; carry || !vli_is_zero(q, ndigits); i++) {
+		u64 qc[ECC_MAX_DIGITS * 2];
+
+		vli_umult(qc, q, c2, ndigits);
+		if (carry)
+			vli_uadd(qc, qc, mod[0], ndigits * 2);
+		vli_set(q, qc + ndigits, ndigits);
+		vli_clear(qc + ndigits, ndigits);
+		carry = vli_is_negative(qc, ndigits);
+		if (carry)
+			qc[ndigits - 1] &= (1ull << 63) - 1;
+		if (i & 1)
+			vli_sub(r, r, qc, ndigits * 2);
+		else
+			vli_add(r, r, qc, ndigits * 2);
+	}
+	while (vli_is_negative(r, ndigits * 2))
+		vli_add(r, r, m, ndigits * 2);
+	while (vli_cmp(r, m, ndigits * 2) >= 0)
+		vli_sub(r, r, m, ndigits * 2);
+
+	vli_set(result, r, ndigits);
+}
+
+/*
+ * Computes result = product % mod, where product is 2N words long.
+ * Reference: Ken MacKay's micro-ecc.
+ * Currently only designed to work for curve_p or curve_n.
+ */
+static void vli_mmod_slow(u64 *result, u64 *product, const u64 *mod,
+			  unsigned int ndigits)
+{
+	u64 mod_m[2 * ECC_MAX_DIGITS];
+	u64 tmp[2 * ECC_MAX_DIGITS];
+	u64 *v[2] = { tmp, product };
+	u64 carry = 0;
+	unsigned int i;
+	/* Shift mod so its highest set bit is at the maximum position. */
+	int shift = (ndigits * 2 * 64) - vli_num_bits(mod, ndigits);
+	int word_shift = shift / 64;
+	int bit_shift = shift % 64;
+
+	vli_clear(mod_m, word_shift);
+	if (bit_shift > 0) {
+		for (i = 0; i < ndigits; ++i) {
+			mod_m[word_shift + i] = (mod[i] << bit_shift) | carry;
+			carry = mod[i] >> (64 - bit_shift);
+		}
+	} else
+		vli_set(mod_m + word_shift, mod, ndigits);
+
+	for (i = 1; shift >= 0; --shift) {
+		u64 borrow = 0;
+		unsigned int j;
+
+		for (j = 0; j < ndigits * 2; ++j) {
+			u64 diff = v[i][j] - mod_m[j] - borrow;
+
+			if (diff != v[i][j])
+				borrow = (diff > v[i][j]);
+			v[1 - i][j] = diff;
+		}
+		i = !(i ^ borrow); /* Swap the index if there was no borrow */
+		vli_rshift1(mod_m, ndigits);
+		mod_m[ndigits - 1] |= mod_m[ndigits] << (64 - 1);
+		vli_rshift1(mod_m + ndigits, ndigits);
+	}
+	vli_set(result, v[i], ndigits);
+}
+
+/* Computes result = product % mod using Barrett's reduction with precomputed
+ * value mu appended to the mod after ndigits, mu = (2^{2w} / mod) and have
+ * length ndigits + 1, where mu * (2^w - 1) should not overflow ndigits
+ * boundary.
+ *
+ * Reference:
+ * R. Brent, P. Zimmermann. Modern Computer Arithmetic. 2010.
+ * 2.4.1 Barrett's algorithm. Algorithm 2.5.
+ */
+static void vli_mmod_barrett(u64 *result, u64 *product, const u64 *mod,
+			     unsigned int ndigits)
+{
+	u64 q[ECC_MAX_DIGITS * 2];
+	u64 r[ECC_MAX_DIGITS * 2];
+	const u64 *mu = mod + ndigits;
+
+	vli_mult(q, product + ndigits, mu, ndigits);
+	if (mu[ndigits])
+		vli_add(q + ndigits, q + ndigits, product + ndigits, ndigits);
+	vli_mult(r, mod, q + ndigits, ndigits);
+	vli_sub(r, product, r, ndigits * 2);
+	while (!vli_is_zero(r + ndigits, ndigits) ||
+	       vli_cmp(r, mod, ndigits) != -1) {
+		u64 carry;
+
+		carry = vli_sub(r, r, mod, ndigits);
+		vli_usub(r + ndigits, r + ndigits, carry, ndigits);
+	}
+	vli_set(result, r, ndigits);
+}
+
 /* Computes p_result = p_product % curve_p.
  * See algorithm 5 and 6 from
  * http://www.isys.uni-klu.ac.at/PDF/2001-0126-MT.pdf
@@ -409,7 +713,7 @@ static void vli_mod_sub(u64 *result, const u64 *left, const u64 *right,
 static void vli_mmod_fast_192(u64 *result, const u64 *product,
 			      const u64 *curve_prime, u64 *tmp)
 {
-	const unsigned int ndigits = 3;
+	const unsigned int ndigits = ECC_CURVE_NIST_P192_DIGITS;
 	int carry;
 
 	vli_set(result, product, ndigits);
@@ -437,7 +741,7 @@ static void vli_mmod_fast_256(u64 *result, const u64 *product,
 			      const u64 *curve_prime, u64 *tmp)
 {
 	int carry;
-	const unsigned int ndigits = 4;
+	const unsigned int ndigits = ECC_CURVE_NIST_P256_DIGITS;
 
 	/* t */
 	vli_set(result, product, ndigits);
@@ -509,47 +813,222 @@ static void vli_mmod_fast_256(u64 *result, const u64 *product,
 	}
 }
 
+#define SL32OR32(x32, y32) (((u64)x32 << 32) | y32)
+#define AND64H(x64)  (x64 & 0xffFFffFF00000000ull)
+#define AND64L(x64)  (x64 & 0x00000000ffFFffFFull)
+
 /* Computes result = product % curve_prime
- *  from http://www.nsa.gov/ia/_files/nist-routines.pdf
-*/
+ * from "Mathematical routines for the NIST prime elliptic curves"
+ */
+static void vli_mmod_fast_384(u64 *result, const u64 *product,
+				const u64 *curve_prime, u64 *tmp)
+{
+	int carry;
+	const unsigned int ndigits = ECC_CURVE_NIST_P384_DIGITS;
+
+	/* t */
+	vli_set(result, product, ndigits);
+
+	/* s1 */
+	tmp[0] = 0;		// 0 || 0
+	tmp[1] = 0;		// 0 || 0
+	tmp[2] = SL32OR32(product[11], (product[10]>>32));	//a22||a21
+	tmp[3] = product[11]>>32;	// 0 ||a23
+	tmp[4] = 0;		// 0 || 0
+	tmp[5] = 0;		// 0 || 0
+	carry = vli_lshift(tmp, tmp, 1, ndigits);
+	carry += vli_add(result, result, tmp, ndigits);
+
+	/* s2 */
+	tmp[0] = product[6];	//a13||a12
+	tmp[1] = product[7];	//a15||a14
+	tmp[2] = product[8];	//a17||a16
+	tmp[3] = product[9];	//a19||a18
+	tmp[4] = product[10];	//a21||a20
+	tmp[5] = product[11];	//a23||a22
+	carry += vli_add(result, result, tmp, ndigits);
+
+	/* s3 */
+	tmp[0] = SL32OR32(product[11], (product[10]>>32));	//a22||a21
+	tmp[1] = SL32OR32(product[6], (product[11]>>32));	//a12||a23
+	tmp[2] = SL32OR32(product[7], (product[6])>>32);	//a14||a13
+	tmp[3] = SL32OR32(product[8], (product[7]>>32));	//a16||a15
+	tmp[4] = SL32OR32(product[9], (product[8]>>32));	//a18||a17
+	tmp[5] = SL32OR32(product[10], (product[9]>>32));	//a20||a19
+	carry += vli_add(result, result, tmp, ndigits);
+
+	/* s4 */
+	tmp[0] = AND64H(product[11]);	//a23|| 0
+	tmp[1] = (product[10]<<32);	//a20|| 0
+	tmp[2] = product[6];	//a13||a12
+	tmp[3] = product[7];	//a15||a14
+	tmp[4] = product[8];	//a17||a16
+	tmp[5] = product[9];	//a19||a18
+	carry += vli_add(result, result, tmp, ndigits);
+
+	/* s5 */
+	tmp[0] = 0;		//  0|| 0
+	tmp[1] = 0;		//  0|| 0
+	tmp[2] = product[10];	//a21||a20
+	tmp[3] = product[11];	//a23||a22
+	tmp[4] = 0;		//  0|| 0
+	tmp[5] = 0;		//  0|| 0
+	carry += vli_add(result, result, tmp, ndigits);
+
+	/* s6 */
+	tmp[0] = AND64L(product[10]);	// 0 ||a20
+	tmp[1] = AND64H(product[10]);	//a21|| 0
+	tmp[2] = product[11];	//a23||a22
+	tmp[3] = 0;		// 0 || 0
+	tmp[4] = 0;		// 0 || 0
+	tmp[5] = 0;		// 0 || 0
+	carry += vli_add(result, result, tmp, ndigits);
+
+	/* d1 */
+	tmp[0] = SL32OR32(product[6], (product[11]>>32));	//a12||a23
+	tmp[1] = SL32OR32(product[7], (product[6]>>32));	//a14||a13
+	tmp[2] = SL32OR32(product[8], (product[7]>>32));	//a16||a15
+	tmp[3] = SL32OR32(product[9], (product[8]>>32));	//a18||a17
+	tmp[4] = SL32OR32(product[10], (product[9]>>32));	//a20||a19
+	tmp[5] = SL32OR32(product[11], (product[10]>>32));	//a22||a21
+	carry -= vli_sub(result, result, tmp, ndigits);
+
+	/* d2 */
+	tmp[0] = (product[10]<<32);	//a20|| 0
+	tmp[1] = SL32OR32(product[11], (product[10]>>32));	//a22||a21
+	tmp[2] = (product[11]>>32);	// 0 ||a23
+	tmp[3] = 0;		// 0 || 0
+	tmp[4] = 0;		// 0 || 0
+	tmp[5] = 0;		// 0 || 0
+	carry -= vli_sub(result, result, tmp, ndigits);
+
+	/* d3 */
+	tmp[0] = 0;		// 0 || 0
+	tmp[1] = AND64H(product[11]);	//a23|| 0
+	tmp[2] = product[11]>>32;	// 0 ||a23
+	tmp[3] = 0;		// 0 || 0
+	tmp[4] = 0;		// 0 || 0
+	tmp[5] = 0;		// 0 || 0
+	carry -= vli_sub(result, result, tmp, ndigits);
+
+	if (carry < 0) {
+		do {
+			carry += vli_add(result, result, curve_prime, ndigits);
+		} while (carry < 0);
+	} else {
+		while (carry || vli_cmp(curve_prime, result, ndigits) != 1)
+			carry -= vli_sub(result, result, curve_prime, ndigits);
+	}
+
+}
+
+#undef SL32OR32
+#undef AND64H
+#undef AND64L
+
+/*
+ * Computes result = product % curve_prime
+ * from "Recommendations for Discrete Logarithm-Based Cryptography:
+ *       Elliptic Curve Domain Parameters" section G.1.4
+ */
+static void vli_mmod_fast_521(u64 *result, const u64 *product,
+			      const u64 *curve_prime, u64 *tmp)
+{
+	const unsigned int ndigits = ECC_CURVE_NIST_P521_DIGITS;
+	size_t i;
+
+	/* Initialize result with lowest 521 bits from product */
+	vli_set(result, product, ndigits);
+	result[8] &= 0x1ff;
+
+	for (i = 0; i < ndigits; i++)
+		tmp[i] = (product[8 + i] >> 9) | (product[9 + i] << 55);
+	tmp[8] &= 0x1ff;
+
+	vli_mod_add(result, result, tmp, curve_prime, ndigits);
+}
+
+/* Computes result = product % curve_prime for different curve_primes.
+ *
+ * Note that curve_primes are distinguished just by heuristic check and
+ * not by complete conformance check.
+ */
 static bool vli_mmod_fast(u64 *result, u64 *product,
-			  const u64 *curve_prime, unsigned int ndigits)
+			  const struct ecc_curve *curve)
 {
 	u64 tmp[2 * ECC_MAX_DIGITS];
+	const u64 *curve_prime = curve->p;
+	const unsigned int ndigits = curve->g.ndigits;
+
+	/* All NIST curves have name prefix 'nist_' */
+	if (strncmp(curve->name, "nist_", 5) != 0) {
+		/* Try to handle Pseudo-Marsenne primes. */
+		if (curve_prime[ndigits - 1] == -1ull) {
+			vli_mmod_special(result, product, curve_prime,
+					 ndigits);
+			return true;
+		} else if (curve_prime[ndigits - 1] == 1ull << 63 &&
+			   curve_prime[ndigits - 2] == 0) {
+			vli_mmod_special2(result, product, curve_prime,
+					  ndigits);
+			return true;
+		}
+		vli_mmod_barrett(result, product, curve_prime, ndigits);
+		return true;
+	}
 
 	switch (ndigits) {
-	case 3:
+	case ECC_CURVE_NIST_P192_DIGITS:
 		vli_mmod_fast_192(result, product, curve_prime, tmp);
 		break;
-	case 4:
+	case ECC_CURVE_NIST_P256_DIGITS:
 		vli_mmod_fast_256(result, product, curve_prime, tmp);
 		break;
+	case ECC_CURVE_NIST_P384_DIGITS:
+		vli_mmod_fast_384(result, product, curve_prime, tmp);
+		break;
+	case ECC_CURVE_NIST_P521_DIGITS:
+		vli_mmod_fast_521(result, product, curve_prime, tmp);
+		break;
 	default:
-		pr_err("unsupports digits size!\n");
+		pr_err_ratelimited("ecc: unsupported digits size!\n");
 		return false;
 	}
 
 	return true;
 }
 
+/* Computes result = (left * right) % mod.
+ * Assumes that mod is big enough curve order.
+ */
+void vli_mod_mult_slow(u64 *result, const u64 *left, const u64 *right,
+		       const u64 *mod, unsigned int ndigits)
+{
+	u64 product[ECC_MAX_DIGITS * 2];
+
+	vli_mult(product, left, right, ndigits);
+	vli_mmod_slow(result, product, mod, ndigits);
+}
+EXPORT_SYMBOL(vli_mod_mult_slow);
+
 /* Computes result = (left * right) % curve_prime. */
 static void vli_mod_mult_fast(u64 *result, const u64 *left, const u64 *right,
-			      const u64 *curve_prime, unsigned int ndigits)
+			      const struct ecc_curve *curve)
 {
 	u64 product[2 * ECC_MAX_DIGITS];
 
-	vli_mult(product, left, right, ndigits);
-	vli_mmod_fast(result, product, curve_prime, ndigits);
+	vli_mult(product, left, right, curve->g.ndigits);
+	vli_mmod_fast(result, product, curve);
 }
 
 /* Computes result = left^2 % curve_prime. */
 static void vli_mod_square_fast(u64 *result, const u64 *left,
-				const u64 *curve_prime, unsigned int ndigits)
+				const struct ecc_curve *curve)
 {
 	u64 product[2 * ECC_MAX_DIGITS];
 
-	vli_square(product, left, ndigits);
-	vli_mmod_fast(result, product, curve_prime, ndigits);
+	vli_square(product, left, curve->g.ndigits);
+	vli_mmod_fast(result, product, curve);
 }
 
 #define EVEN(vli) (!(vli[0] & 1))
@@ -557,7 +1036,7 @@ 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];
@@ -630,41 +1109,45 @@ 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 ------ */
 
 /* 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 http://eprint.iacr.org/2011/338.pdf
+ * coordinates. From https://eprint.iacr.org/2011/338.pdf
  */
 
 /* Double in place */
 static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1,
-				      u64 *curve_prime, unsigned int ndigits)
+					const struct ecc_curve *curve)
 {
 	/* t1 = x, t2 = y, t3 = z */
 	u64 t4[ECC_MAX_DIGITS];
 	u64 t5[ECC_MAX_DIGITS];
+	const u64 *curve_prime = curve->p;
+	const unsigned int ndigits = curve->g.ndigits;
 
 	if (vli_is_zero(z1, ndigits))
 		return;
 
 	/* t4 = y1^2 */
-	vli_mod_square_fast(t4, y1, curve_prime, ndigits);
+	vli_mod_square_fast(t4, y1, curve);
 	/* t5 = x1*y1^2 = A */
-	vli_mod_mult_fast(t5, x1, t4, curve_prime, ndigits);
+	vli_mod_mult_fast(t5, x1, t4, curve);
 	/* t4 = y1^4 */
-	vli_mod_square_fast(t4, t4, curve_prime, ndigits);
+	vli_mod_square_fast(t4, t4, curve);
 	/* t2 = y1*z1 = z3 */
-	vli_mod_mult_fast(y1, y1, z1, curve_prime, ndigits);
+	vli_mod_mult_fast(y1, y1, z1, curve);
 	/* t3 = z1^2 */
-	vli_mod_square_fast(z1, z1, curve_prime, ndigits);
+	vli_mod_square_fast(z1, z1, curve);
 
 	/* t1 = x1 + z1^2 */
 	vli_mod_add(x1, x1, z1, curve_prime, ndigits);
@@ -673,7 +1156,7 @@ static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1,
 	/* t3 = x1 - z1^2 */
 	vli_mod_sub(z1, x1, z1, curve_prime, ndigits);
 	/* t1 = x1^2 - z1^4 */
-	vli_mod_mult_fast(x1, x1, z1, curve_prime, ndigits);
+	vli_mod_mult_fast(x1, x1, z1, curve);
 
 	/* t3 = 2*(x1^2 - z1^4) */
 	vli_mod_add(z1, x1, x1, curve_prime, ndigits);
@@ -690,7 +1173,7 @@ static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1,
 	/* t1 = 3/2*(x1^2 - z1^4) = B */
 
 	/* t3 = B^2 */
-	vli_mod_square_fast(z1, x1, curve_prime, ndigits);
+	vli_mod_square_fast(z1, x1, curve);
 	/* t3 = B^2 - A */
 	vli_mod_sub(z1, z1, t5, curve_prime, ndigits);
 	/* t3 = B^2 - 2A = x3 */
@@ -698,7 +1181,7 @@ static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1,
 	/* t5 = A - x3 */
 	vli_mod_sub(t5, t5, z1, curve_prime, ndigits);
 	/* t1 = B * (A - x3) */
-	vli_mod_mult_fast(x1, x1, t5, curve_prime, ndigits);
+	vli_mod_mult_fast(x1, x1, t5, curve);
 	/* t4 = B * (A - x3) - y1^4 = y3 */
 	vli_mod_sub(t4, x1, t4, curve_prime, ndigits);
 
@@ -708,23 +1191,22 @@ static void ecc_point_double_jacobian(u64 *x1, u64 *y1, u64 *z1,
 }
 
 /* Modify (x1, y1) => (x1 * z^2, y1 * z^3) */
-static void apply_z(u64 *x1, u64 *y1, u64 *z, u64 *curve_prime,
-		    unsigned int ndigits)
+static void apply_z(u64 *x1, u64 *y1, u64 *z, const struct ecc_curve *curve)
 {
 	u64 t1[ECC_MAX_DIGITS];
 
-	vli_mod_square_fast(t1, z, curve_prime, ndigits);    /* z^2 */
-	vli_mod_mult_fast(x1, x1, t1, curve_prime, ndigits); /* x1 * z^2 */
-	vli_mod_mult_fast(t1, t1, z, curve_prime, ndigits);  /* z^3 */
-	vli_mod_mult_fast(y1, y1, t1, curve_prime, ndigits); /* y1 * z^3 */
+	vli_mod_square_fast(t1, z, curve);		/* z^2 */
+	vli_mod_mult_fast(x1, x1, t1, curve);	/* x1 * z^2 */
+	vli_mod_mult_fast(t1, t1, z, curve);	/* z^3 */
+	vli_mod_mult_fast(y1, y1, t1, curve);	/* 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 *curve_prime,
-				unsigned int ndigits)
+				u64 *p_initial_z, const struct ecc_curve *curve)
 {
 	u64 z[ECC_MAX_DIGITS];
+	const unsigned int ndigits = curve->g.ndigits;
 
 	vli_set(x2, x1, ndigits);
 	vli_set(y2, y1, ndigits);
@@ -735,35 +1217,37 @@ static void xycz_initial_double(u64 *x1, u64 *y1, u64 *x2, u64 *y2,
 	if (p_initial_z)
 		vli_set(z, p_initial_z, ndigits);
 
-	apply_z(x1, y1, z, curve_prime, ndigits);
+	apply_z(x1, y1, z, curve);
 
-	ecc_point_double_jacobian(x1, y1, z, curve_prime, ndigits);
+	ecc_point_double_jacobian(x1, y1, z, curve);
 
-	apply_z(x2, y2, z, curve_prime, ndigits);
+	apply_z(x2, y2, z, curve);
 }
 
 /* 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, u64 *curve_prime,
-		     unsigned int ndigits)
+static void xycz_add(u64 *x1, u64 *y1, u64 *x2, u64 *y2,
+			const struct ecc_curve *curve)
 {
 	/* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
 	u64 t5[ECC_MAX_DIGITS];
+	const u64 *curve_prime = curve->p;
+	const unsigned int ndigits = curve->g.ndigits;
 
 	/* t5 = x2 - x1 */
 	vli_mod_sub(t5, x2, x1, curve_prime, ndigits);
 	/* t5 = (x2 - x1)^2 = A */
-	vli_mod_square_fast(t5, t5, curve_prime, ndigits);
+	vli_mod_square_fast(t5, t5, curve);
 	/* t1 = x1*A = B */
-	vli_mod_mult_fast(x1, x1, t5, curve_prime, ndigits);
+	vli_mod_mult_fast(x1, x1, t5, curve);
 	/* t3 = x2*A = C */
-	vli_mod_mult_fast(x2, x2, t5, curve_prime, ndigits);
+	vli_mod_mult_fast(x2, x2, t5, curve);
 	/* t4 = y2 - y1 */
 	vli_mod_sub(y2, y2, y1, curve_prime, ndigits);
 	/* t5 = (y2 - y1)^2 = D */
-	vli_mod_square_fast(t5, y2, curve_prime, ndigits);
+	vli_mod_square_fast(t5, y2, curve);
 
 	/* t5 = D - B */
 	vli_mod_sub(t5, t5, x1, curve_prime, ndigits);
@@ -772,11 +1256,11 @@ static void xycz_add(u64 *x1, u64 *y1, u64 *x2, u64 *y2, u64 *curve_prime,
 	/* t3 = C - B */
 	vli_mod_sub(x2, x2, x1, curve_prime, ndigits);
 	/* t2 = y1*(C - B) */
-	vli_mod_mult_fast(y1, y1, x2, curve_prime, ndigits);
+	vli_mod_mult_fast(y1, y1, x2, curve);
 	/* t3 = B - x3 */
 	vli_mod_sub(x2, x1, t5, curve_prime, ndigits);
 	/* t4 = (y2 - y1)*(B - x3) */
-	vli_mod_mult_fast(y2, y2, x2, curve_prime, ndigits);
+	vli_mod_mult_fast(y2, y2, x2, curve);
 	/* t4 = y3 */
 	vli_mod_sub(y2, y2, y1, curve_prime, ndigits);
 
@@ -787,22 +1271,24 @@ static void xycz_add(u64 *x1, u64 *y1, u64 *x2, u64 *y2, u64 *curve_prime,
  * 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, u64 *curve_prime,
-		       unsigned int ndigits)
+static void xycz_add_c(u64 *x1, u64 *y1, u64 *x2, u64 *y2,
+			const struct ecc_curve *curve)
 {
 	/* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */
 	u64 t5[ECC_MAX_DIGITS];
 	u64 t6[ECC_MAX_DIGITS];
 	u64 t7[ECC_MAX_DIGITS];
+	const u64 *curve_prime = curve->p;
+	const unsigned int ndigits = curve->g.ndigits;
 
 	/* t5 = x2 - x1 */
 	vli_mod_sub(t5, x2, x1, curve_prime, ndigits);
 	/* t5 = (x2 - x1)^2 = A */
-	vli_mod_square_fast(t5, t5, curve_prime, ndigits);
+	vli_mod_square_fast(t5, t5, curve);
 	/* t1 = x1*A = B */
-	vli_mod_mult_fast(x1, x1, t5, curve_prime, ndigits);
+	vli_mod_mult_fast(x1, x1, t5, curve);
 	/* t3 = x2*A = C */
-	vli_mod_mult_fast(x2, x2, t5, curve_prime, ndigits);
+	vli_mod_mult_fast(x2, x2, t5, curve);
 	/* t4 = y2 + y1 */
 	vli_mod_add(t5, y2, y1, curve_prime, ndigits);
 	/* t4 = y2 - y1 */
@@ -811,29 +1297,29 @@ static void xycz_add_c(u64 *x1, u64 *y1, u64 *x2, u64 *y2, u64 *curve_prime,
 	/* t6 = C - B */
 	vli_mod_sub(t6, x2, x1, curve_prime, ndigits);
 	/* t2 = y1 * (C - B) */
-	vli_mod_mult_fast(y1, y1, t6, curve_prime, ndigits);
+	vli_mod_mult_fast(y1, y1, t6, curve);
 	/* t6 = B + C */
 	vli_mod_add(t6, x1, x2, curve_prime, ndigits);
 	/* t3 = (y2 - y1)^2 */
-	vli_mod_square_fast(x2, y2, curve_prime, ndigits);
+	vli_mod_square_fast(x2, y2, curve);
 	/* t3 = x3 */
 	vli_mod_sub(x2, x2, t6, curve_prime, ndigits);
 
 	/* t7 = B - x3 */
 	vli_mod_sub(t7, x1, x2, curve_prime, ndigits);
 	/* t4 = (y2 - y1)*(B - x3) */
-	vli_mod_mult_fast(y2, y2, t7, curve_prime, ndigits);
+	vli_mod_mult_fast(y2, y2, t7, curve);
 	/* t4 = y3 */
 	vli_mod_sub(y2, y2, y1, curve_prime, ndigits);
 
 	/* t7 = (y2 + y1)^2 = F */
-	vli_mod_square_fast(t7, t5, curve_prime, ndigits);
+	vli_mod_square_fast(t7, t5, curve);
 	/* t7 = x3' */
 	vli_mod_sub(t7, t7, t6, curve_prime, ndigits);
 	/* t6 = x3' - B */
 	vli_mod_sub(t6, t7, x1, curve_prime, ndigits);
 	/* t6 = (y2 + y1)*(x3' - B) */
-	vli_mod_mult_fast(t6, t6, t5, curve_prime, ndigits);
+	vli_mod_mult_fast(t6, t6, t5, curve);
 	/* t2 = y3' */
 	vli_mod_sub(y1, t6, y1, curve_prime, ndigits);
 
@@ -858,60 +1344,136 @@ static void ecc_point_mult(struct ecc_point *result,
 	carry = vli_add(sk[0], scalar, curve->n, ndigits);
 	vli_add(sk[1], sk[0], curve->n, ndigits);
 	scalar = sk[!carry];
-	num_bits = sizeof(u64) * ndigits * 8 + 1;
+	if (curve->nbits == 521)	/* NIST P521 */
+		num_bits = curve->nbits + 2;
+	else
+		num_bits = sizeof(u64) * ndigits * 8 + 1;
 
 	vli_set(rx[1], point->x, ndigits);
 	vli_set(ry[1], point->y, ndigits);
 
-	xycz_initial_double(rx[1], ry[1], rx[0], ry[0], initial_z, curve_prime,
-			    ndigits);
+	xycz_initial_double(rx[1], ry[1], rx[0], ry[0], initial_z, curve);
 
 	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], curve_prime,
-			   ndigits);
-		xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb], curve_prime,
-			 ndigits);
+		xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb], curve);
+		xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb], curve);
 	}
 
 	nb = !vli_test_bit(scalar, 0);
-	xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb], curve_prime,
-		   ndigits);
+	xycz_add_c(rx[1 - nb], ry[1 - nb], rx[nb], ry[nb], curve);
 
 	/* Find final 1/Z value. */
 	/* X1 - X0 */
 	vli_mod_sub(z, rx[1], rx[0], curve_prime, ndigits);
 	/* Yb * (X1 - X0) */
-	vli_mod_mult_fast(z, z, ry[1 - nb], curve_prime, ndigits);
+	vli_mod_mult_fast(z, z, ry[1 - nb], curve);
 	/* xP * Yb * (X1 - X0) */
-	vli_mod_mult_fast(z, z, point->x, curve_prime, ndigits);
+	vli_mod_mult_fast(z, z, point->x, curve);
 
 	/* 1 / (xP * Yb * (X1 - X0)) */
 	vli_mod_inv(z, z, curve_prime, point->ndigits);
 
 	/* yP / (xP * Yb * (X1 - X0)) */
-	vli_mod_mult_fast(z, z, point->y, curve_prime, ndigits);
+	vli_mod_mult_fast(z, z, point->y, curve);
 	/* Xb * yP / (xP * Yb * (X1 - X0)) */
-	vli_mod_mult_fast(z, z, rx[1 - nb], curve_prime, ndigits);
+	vli_mod_mult_fast(z, z, rx[1 - nb], curve);
 	/* End 1/Z calculation */
 
-	xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb], curve_prime, ndigits);
+	xycz_add(rx[nb], ry[nb], rx[1 - nb], ry[1 - nb], curve);
 
-	apply_z(rx[0], ry[0], z, curve_prime, ndigits);
+	apply_z(rx[0], ry[0], z, curve);
 
 	vli_set(result->x, rx[0], ndigits);
 	vli_set(result->y, ry[0], ndigits);
 }
 
-static inline void ecc_swap_digits(const u64 *in, u64 *out,
-				   unsigned int ndigits)
+/* Computes R = P + Q mod p */
+static void ecc_point_add(const struct ecc_point *result,
+		   const struct ecc_point *p, const struct ecc_point *q,
+		   const struct ecc_curve *curve)
 {
+	u64 z[ECC_MAX_DIGITS];
+	u64 px[ECC_MAX_DIGITS];
+	u64 py[ECC_MAX_DIGITS];
+	unsigned int ndigits = curve->g.ndigits;
+
+	vli_set(result->x, q->x, ndigits);
+	vli_set(result->y, q->y, ndigits);
+	vli_mod_sub(z, result->x, p->x, curve->p, ndigits);
+	vli_set(px, p->x, ndigits);
+	vli_set(py, p->y, ndigits);
+	xycz_add(px, py, result->x, result->y, curve);
+	vli_mod_inv(z, z, curve->p, ndigits);
+	apply_z(result->x, result->y, z, curve);
+}
+
+/* Computes R = u1P + u2Q mod p using Shamir's trick.
+ * Based on: Kenneth MacKay's micro-ecc (2014).
+ */
+void ecc_point_mult_shamir(const struct ecc_point *result,
+			   const u64 *u1, const struct ecc_point *p,
+			   const u64 *u2, const struct ecc_point *q,
+			   const struct ecc_curve *curve)
+{
+	u64 z[ECC_MAX_DIGITS];
+	u64 sump[2][ECC_MAX_DIGITS];
+	u64 *rx = result->x;
+	u64 *ry = result->y;
+	unsigned int ndigits = curve->g.ndigits;
+	unsigned int num_bits;
+	struct ecc_point sum = ECC_POINT_INIT(sump[0], sump[1], ndigits);
+	const struct ecc_point *points[4];
+	const struct ecc_point *point;
+	unsigned int idx;
 	int i;
 
-	for (i = 0; i < ndigits; i++)
-		out[i] = __swab64(in[ndigits - 1 - i]);
+	ecc_point_add(&sum, p, q, curve);
+	points[0] = NULL;
+	points[1] = p;
+	points[2] = q;
+	points[3] = &sum;
+
+	num_bits = max(vli_num_bits(u1, ndigits), vli_num_bits(u2, ndigits));
+	i = num_bits - 1;
+	idx = !!vli_test_bit(u1, i);
+	idx |= (!!vli_test_bit(u2, i)) << 1;
+	point = points[idx];
+
+	vli_set(rx, point->x, ndigits);
+	vli_set(ry, point->y, ndigits);
+	vli_clear(z + 1, ndigits - 1);
+	z[0] = 1;
+
+	for (--i; i >= 0; i--) {
+		ecc_point_double_jacobian(rx, ry, z, curve);
+		idx = !!vli_test_bit(u1, i);
+		idx |= (!!vli_test_bit(u2, i)) << 1;
+		point = points[idx];
+		if (point) {
+			u64 tx[ECC_MAX_DIGITS];
+			u64 ty[ECC_MAX_DIGITS];
+			u64 tz[ECC_MAX_DIGITS];
+
+			vli_set(tx, point->x, ndigits);
+			vli_set(ty, point->y, ndigits);
+			apply_z(tx, ty, z, curve);
+			vli_mod_sub(tz, rx, tx, curve->p, ndigits);
+			xycz_add(tx, ty, rx, ry, curve);
+			vli_mod_mult_fast(z, z, tz, curve);
+		}
+	}
+	vli_mod_inv(z, z, curve->p, ndigits);
+	apply_z(rx, ry, z, curve);
 }
+EXPORT_SYMBOL(ecc_point_mult_shamir);
 
+/*
+ * This function performs checks equivalent to Appendix A.4.2 of FIPS 186-5.
+ * Whereas A.4.2 results in an integer in the interval [1, n-1], this function
+ * ensures that the integer is in the range of [2, n-3]. We are slightly
+ * stricter because of the currently used scalar multiplication algorithm.
+ */
 static int __ecc_is_key_valid(const struct ecc_curve *curve,
 			      const u64 *private_key, unsigned int ndigits)
 {
@@ -948,33 +1510,32 @@ 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,
- * equivalent to that described in FIPS 186-4, Appendix B.4.1.
- *
- * d = (c mod(n–1)) + 1    where c is a string of random bits, 64 bits longer
- *                         than requested
- * 0 <= c mod(n-1) <= n-2  and implies that
- * 1 <= d <= n-1
+ * ECC private keys are generated using the method of rejection sampling,
+ * equivalent to that described in FIPS 186-5, Appendix A.2.2.
  *
  * This method generates a private key uniformly distributed in the range
- * [1, n-1].
+ * [2, n-3].
  */
-int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey)
+int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits,
+		    u64 *private_key)
 {
 	const struct ecc_curve *curve = ecc_get_curve(curve_id);
-	u64 priv[ECC_MAX_DIGITS];
 	unsigned int nbytes = ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
 	unsigned int nbits = vli_num_bits(curve->n, ndigits);
 	int err;
 
-	/* Check that N is included in Table 1 of FIPS 186-4, section 6.1.1 */
-	if (nbits < 160 || ndigits > ARRAY_SIZE(priv))
+	/*
+	 * Step 1 & 2: check that N is included in Table 1 of FIPS 186-5,
+	 * section 6.1.1.
+	 */
+	if (nbits < 224)
 		return -EINVAL;
 
 	/*
-	 * FIPS 186-4 recommends that the private key should be obtained from a
+	 * FIPS 186-5 recommends that the private key should be obtained from a
 	 * RBG with a security strength equal to or greater than the security
 	 * strength associated with N.
 	 *
@@ -987,43 +1548,43 @@ int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey)
 	if (crypto_get_default_rng())
 		return -EFAULT;
 
-	err = crypto_rng_get_bytes(crypto_default_rng, (u8 *)priv, nbytes);
+	/* Step 3: obtain N returned_bits from the DRBG. */
+	err = crypto_rng_get_bytes(crypto_default_rng,
+				   (u8 *)private_key, nbytes);
 	crypto_put_default_rng();
 	if (err)
 		return err;
 
-	/* Make sure the private key is in the valid range. */
-	if (__ecc_is_key_valid(curve, priv, ndigits))
+	/* Step 4: make sure the private key is in the valid range. */
+	if (__ecc_is_key_valid(curve, private_key, ndigits))
 		return -EINVAL;
 
-	ecc_swap_digits(priv, privkey, ndigits);
-
 	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)
 {
 	int ret = 0;
 	struct ecc_point *pk;
-	u64 priv[ECC_MAX_DIGITS];
 	const struct ecc_curve *curve = ecc_get_curve(curve_id);
 
-	if (!private_key || !curve || ndigits > ARRAY_SIZE(priv)) {
+	if (!private_key) {
 		ret = -EINVAL;
 		goto out;
 	}
 
-	ecc_swap_digits(private_key, priv, ndigits);
-
 	pk = ecc_alloc_point(ndigits);
 	if (!pk) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	ecc_point_mult(pk, &curve->g, priv, NULL, curve, ndigits);
-	if (ecc_point_is_zero(pk)) {
+	ecc_point_mult(pk, &curve->g, private_key, NULL, curve, ndigits);
+
+	/* SP800-56A rev 3 5.6.2.1.3 key check */
+	if (ecc_is_pubkey_valid_full(curve, pk)) {
 		ret = -EAGAIN;
 		goto err_free_point;
 	}
@@ -1036,13 +1597,17 @@ err_free_point:
 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];
 
+	if (WARN_ON(pk->ndigits != curve->g.ndigits))
+		return -EINVAL;
+
 	/* Check 1: Verify key is not the zero point. */
 	if (ecc_point_is_zero(pk))
 		return -EINVAL;
@@ -1054,18 +1619,45 @@ static int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
 		return -EINVAL;
 
 	/* Check 3: Verify that y^2 == (x^3 + a·x + b) mod p */
-	vli_mod_square_fast(yy, pk->y, curve->p, pk->ndigits); /* y^2 */
-	vli_mod_square_fast(xxx, pk->x, curve->p, pk->ndigits); /* x^2 */
-	vli_mod_mult_fast(xxx, xxx, pk->x, curve->p, pk->ndigits); /* x^3 */
-	vli_mod_mult_fast(w, curve->a, pk->x, curve->p, pk->ndigits); /* a·x */
+	vli_mod_square_fast(yy, pk->y, curve); /* y^2 */
+	vli_mod_square_fast(xxx, pk->x, curve); /* x^2 */
+	vli_mod_mult_fast(xxx, xxx, pk->x, curve); /* x^3 */
+	vli_mod_mult_fast(w, curve->a, pk->x, curve); /* a·x */
 	vli_mod_add(w, w, curve->b, curve->p, pk->ndigits); /* a·x + b */
 	vli_mod_add(w, w, xxx, curve->p, pk->ndigits); /* x^3 + a·x + b */
 	if (vli_cmp(yy, w, pk->ndigits) != 0) /* Equation */
 		return -EINVAL;
 
 	return 0;
+}
+EXPORT_SYMBOL(ecc_is_pubkey_valid_partial);
 
+/* SP800-56A section 5.6.2.3.3 full verification */
+int ecc_is_pubkey_valid_full(const struct ecc_curve *curve,
+			     struct ecc_point *pk)
+{
+	struct ecc_point *nQ;
+
+	/* Checks 1 through 3 */
+	int ret = ecc_is_pubkey_valid_partial(curve, pk);
+
+	if (ret)
+		return ret;
+
+	/* Check 4: Verify that nQ is the zero point. */
+	nQ = ecc_alloc_point(pk->ndigits);
+	if (!nQ)
+		return -ENOMEM;
+
+	ecc_point_mult(nQ, pk, curve->n, NULL, curve, pk->ndigits);
+	if (!ecc_point_is_zero(nQ))
+		ret = -EINVAL;
+
+	ecc_free_point(nQ);
+
+	return ret;
 }
+EXPORT_SYMBOL(ecc_is_pubkey_valid_full);
 
 int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
 			      const u64 *private_key, const u64 *public_key,
@@ -1073,13 +1665,11 @@ int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
 {
 	int ret = 0;
 	struct ecc_point *product, *pk;
-	u64 priv[ECC_MAX_DIGITS];
 	u64 rand_z[ECC_MAX_DIGITS];
 	unsigned int nbytes;
 	const struct ecc_curve *curve = ecc_get_curve(curve_id);
 
-	if (!private_key || !public_key || !curve ||
-	    ndigits > ARRAY_SIZE(priv) || ndigits > ARRAY_SIZE(rand_z)) {
+	if (!private_key || !public_key || ndigits > ARRAY_SIZE(rand_z)) {
 		ret = -EINVAL;
 		goto out;
 	}
@@ -1100,24 +1690,30 @@ int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
 	if (ret)
 		goto err_alloc_product;
 
-	ecc_swap_digits(private_key, priv, ndigits);
-
 	product = ecc_alloc_point(ndigits);
 	if (!product) {
 		ret = -ENOMEM;
 		goto err_alloc_product;
 	}
 
-	ecc_point_mult(product, pk, priv, rand_z, curve, ndigits);
+	ecc_point_mult(product, pk, private_key, rand_z, curve, ndigits);
 
-	ecc_swap_digits(product->x, secret, ndigits);
-
-	if (ecc_point_is_zero(product))
+	if (ecc_point_is_zero(product)) {
 		ret = -EFAULT;
+		goto err_validity;
+	}
 
+	ecc_swap_digits(product->x, secret, ndigits);
+
+err_validity:
+	memzero_explicit(rand_z, sizeof(rand_z));
 	ecc_free_point(product);
 err_alloc_product:
 	ecc_free_point(pk);
 out:
 	return ret;
 }
+EXPORT_SYMBOL(crypto_ecdh_shared_secret);
+
+MODULE_DESCRIPTION("core elliptic curve module");
+MODULE_LICENSE("Dual BSD/GPL");