Add more crypto_bignum_*() wrappers

These operations will be needed for SAE FCC group operations.

Signed-hostap: Jouni Malinen <j@w1.fi>

src/crypto/crypto.h

@@ -520,6 +520,75 @@ int crypto_bignum_mod(const struct crypto_bignum *a,
 		      const struct crypto_bignum *b,
 		      struct crypto_bignum *c);
 
+/**
+ * crypto_bignum_exptmod - Modular exponentiation: d = a^b (mod c)
+ * @a: Bignum; base
+ * @b: Bignum; exponent
+ * @c: Bignum; modulus
+ * @d: Bignum; used to store the result of a^b (mod c)
+ * Returns: 0 on success, -1 on failure
+ */
+int crypto_bignum_exptmod(const struct crypto_bignum *a,
+			  const struct crypto_bignum *b,
+			  const struct crypto_bignum *c,
+			  struct crypto_bignum *d);
+
+/**
+ * crypto_bignum_rshift - b = a >> n
+ * @a: Bignum
+ * @n: Number of bits to shift
+ * @b: Bignum; used to store the result of a >> n
+ * Returns: 0 on success, -1 on failure
+ */
+int crypto_bignum_rshift(const struct crypto_bignum *a, int n,
+			 struct crypto_bignum *b);
+
+/**
+ * crypto_bignum_inverse - Inverse a bignum so that a * c = 1 (mod b)
+ * @a: Bignum
+ * @b: Bignum
+ * @c: Bignum; used to store the result
+ * Returns: 0 on success, -1 on failure
+ */
+int crypto_bignum_inverse(const struct crypto_bignum *a,
+			  const struct crypto_bignum *b,
+			  struct crypto_bignum *c);
+
+/**
+ * crypto_bignum_sub - 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_sub(const struct crypto_bignum *a,
+		      const struct crypto_bignum *b,
+		      struct crypto_bignum *c);
+
+/**
+ * crypto_bignum_div - 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_div(const struct crypto_bignum *a,
+		      const struct crypto_bignum *b,
+		      struct crypto_bignum *c);
+
+/**
+ * crypto_bignum_mulmod - d = a * b (mod c)
+ * @a: Bignum
+ * @b: Bignum
+ * @c: Bignum
+ * @d: Bignum; used to store the result of (a * b) % c
+ * Returns: 0 on success, -1 on failure
+ */
+int crypto_bignum_mulmod(const struct crypto_bignum *a,
+			 const struct crypto_bignum *b,
+			 const struct crypto_bignum *c,
+			 struct crypto_bignum *d);
+
 /**
  * struct crypto_ec - Elliptic curve context
  *

src/crypto/crypto_openssl.c

@@ -895,6 +895,98 @@ int crypto_bignum_mod(const struct crypto_bignum *a,
 }
 
 
+int crypto_bignum_exptmod(const struct crypto_bignum *a,
+			  const struct crypto_bignum *b,
+			  const struct crypto_bignum *c,
+			  struct crypto_bignum *d)
+{
+	int res;
+	BN_CTX *bnctx;
+
+	bnctx = BN_CTX_new();
+	if (bnctx == NULL)
+		return -1;
+	res = BN_mod_exp((BIGNUM *) d, (const BIGNUM *) a, (const BIGNUM *) b,
+			 (const BIGNUM *) c, bnctx);
+	BN_CTX_free(bnctx);
+
+	return res ? 0 : -1;
+}
+
+
+int crypto_bignum_rshift(const struct crypto_bignum *a, int n,
+			 struct crypto_bignum *b)
+{
+	return BN_rshift((BIGNUM *) b, (const BIGNUM *) a, n) ? 0 : -1;
+}
+
+
+int crypto_bignum_inverse(const struct crypto_bignum *a,
+			  const struct crypto_bignum *b,
+			  struct crypto_bignum *c)
+{
+	BIGNUM *res;
+	BN_CTX *bnctx;
+
+	bnctx = BN_CTX_new();
+	if (bnctx == NULL)
+		return -1;
+	res = BN_mod_inverse((BIGNUM *) c, (const BIGNUM *) a,
+			     (const BIGNUM *) b, bnctx);
+	BN_CTX_free(bnctx);
+
+	return res ? 0 : -1;
+}
+
+
+int crypto_bignum_sub(const struct crypto_bignum *a,
+		      const struct crypto_bignum *b,
+		      struct crypto_bignum *c)
+{
+	return BN_sub((BIGNUM *) c, (const BIGNUM *) a, (const BIGNUM *) b) ?
+		0 : -1;
+}
+
+
+int crypto_bignum_div(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_div((BIGNUM *) c, NULL, (const BIGNUM *) a,
+		     (const BIGNUM *) b, bnctx);
+	BN_CTX_free(bnctx);
+
+	return res ? 0 : -1;
+}
+
+
+int crypto_bignum_mulmod(const struct crypto_bignum *a,
+			 const struct crypto_bignum *b,
+			 const struct crypto_bignum *c,
+			 struct crypto_bignum *d)
+{
+	int res;
+
+	BN_CTX *bnctx;
+
+	bnctx = BN_CTX_new();
+	if (bnctx == NULL)
+		return -1;
+	res = BN_mod_mul((BIGNUM *) d, (const BIGNUM *) a, (const BIGNUM *) b,
+			 (const BIGNUM *) c, bnctx);
+	BN_CTX_free(bnctx);
+
+	return res ? 0 : -1;
+}
+
+
 #ifdef CONFIG_ECC
 
 struct crypto_ec {