From 1cbf181a80d4e4fb9bfdcf41bd686afd3e7dea83 Mon Sep 17 00:00:00 2001
From: HC Yen <hc.yen@mediatek.com>
Date: Wed, 21 Dec 2016 11:12:24 +0800
Subject: [PATCH 3/3] rsa: extend bits of n0-inverse

Extend "rsa,n0-inverse" property to 64 bits.
---
 lib/rsa/rsa-sign.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/lib/rsa/rsa-sign.c b/lib/rsa/rsa-sign.c
index 1f04938..f7bdb54 100644
--- a/lib/rsa/rsa-sign.c
+++ b/lib/rsa/rsa-sign.c
@@ -361,25 +361,26 @@ cleanup:
 /*
  * rsa_get_params(): - Get the important parameters of an RSA public key
  */
-int rsa_get_params(RSA *key, uint64_t *exponent, uint32_t *n0_invp,
+int rsa_get_params(RSA *key, uint64_t *exponent, BIGNUM **n0_invp,
 		   BIGNUM **modulusp, BIGNUM **r_squaredp)
 {
-	BIGNUM *big1, *big2, *big32, *big2_32;
-	BIGNUM *n, *r, *r_squared, *tmp;
+	BIGNUM *big1, *big2, *big64, *big2_64;
+	BIGNUM *n0, *n, *r, *r_squared, *tmp;
 	BN_CTX *bn_ctx = BN_CTX_new();
 	int ret = 0;
 
 	/* Initialize BIGNUMs */
 	big1 = BN_new();
 	big2 = BN_new();
-	big32 = BN_new();
+	big64 = BN_new();
 	r = BN_new();
 	r_squared = BN_new();
 	tmp = BN_new();
-	big2_32 = BN_new();
+	big2_64 = BN_new();
+	n0 = BN_new();
 	n = BN_new();
-	if (!big1 || !big2 || !big32 || !r || !r_squared || !tmp || !big2_32 ||
-	    !n) {
+	if (!big1 || !big2 || !big64 || !r || !r_squared || !tmp || !big2_64 ||
+	    !n0 || !n) {
 		fprintf(stderr, "Out of memory (bignum)\n");
 		return -ENOMEM;
 	}
@@ -388,18 +389,18 @@ int rsa_get_params(RSA *key, uint64_t *exponent, uint32_t *n0_invp,
 		ret = -1;
 
 	if (!BN_copy(n, key->n) || !BN_set_word(big1, 1L) ||
-	    !BN_set_word(big2, 2L) || !BN_set_word(big32, 32L))
+	    !BN_set_word(big2, 2L) || !BN_set_word(big64, 64L))
 		ret = -1;
 
-	/* big2_32 = 2^32 */
-	if (!BN_exp(big2_32, big2, big32, bn_ctx))
+	/* big2_64 = 2^64 */
+	if (!BN_exp(big2_64, big2, big64, bn_ctx))
 		ret = -1;
 
-	/* Calculate n0_inv = -1 / n[0] mod 2^32 */
-	if (!BN_mod_inverse(tmp, n, big2_32, bn_ctx) ||
-	    !BN_sub(tmp, big2_32, tmp))
+	/* Calculate n0_inv = -1 / n[0] mod 2^64 */
+	if (!BN_mod_inverse(n0, n, big2_64, bn_ctx) ||
+	    !BN_sub(n0, big2_64, n0))
 		ret = -1;
-	*n0_invp = BN_get_word(tmp);
+	*n0_invp = n0;
 
 	/* Calculate R = 2^(# of key bits) */
 	if (!BN_set_word(tmp, BN_num_bits(n)) ||
@@ -417,10 +418,10 @@ int rsa_get_params(RSA *key, uint64_t *exponent, uint32_t *n0_invp,
 
 	BN_free(big1);
 	BN_free(big2);
-	BN_free(big32);
+	BN_free(big64);
 	BN_free(r);
 	BN_free(tmp);
-	BN_free(big2_32);
+	BN_free(big2_64);
 	if (ret) {
 		fprintf(stderr, "Bignum operations failed\n");
 		return -ENOMEM;
@@ -490,7 +491,7 @@ int rsa_add_verify_data(struct image_sign_info *info, void *keydest)
 {
 	BIGNUM *modulus, *r_squared;
 	uint64_t exponent;
-	uint32_t n0_inv;
+	BIGNUM *n0_inv;
 	int parent, node;
 	char name[100];
 	int ret;
@@ -544,7 +545,8 @@ int rsa_add_verify_data(struct image_sign_info *info, void *keydest)
 	if (!ret)
 		ret = fdt_setprop_u32(keydest, node, "rsa,num-bits", bits);
 	if (!ret)
-		ret = fdt_setprop_u32(keydest, node, "rsa,n0-inverse", n0_inv);
+		ret = fdt_add_bignum(keydest, node, "rsa,n0-inverse", n0_inv,
+				     64);
 	if (!ret) {
 		ret = fdt_setprop_u64(keydest, node, "rsa,exponent", exponent);
 	}
@@ -567,6 +569,7 @@ int rsa_add_verify_data(struct image_sign_info *info, void *keydest)
 done:
 	BN_free(modulus);
 	BN_free(r_squared);
+	BN_free(n0_inv);
 	if (ret)
 		return ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
 
-- 
1.9.1