external/boringssl: support arbitrary elliptic curve groups.

This change exposes the functions needed to support arbitrary elliptic
curve groups for Android.

Change-Id: I66a3662d393deadd718e43d91420fecf050502c2

3 files changed, 54 insertions, 4 deletions

diff --git a/src/crypto/ec/ec.c b/src/crypto/ec/ec.c
index 5426b8f..5e30730 100644
--- a/src/crypto/ec/ec.c
+++ b/src/crypto/ec/ec.c
@@ -265,8 +265,8 @@ EC_GROUP *ec_group_new(const EC_METHOD *meth) {
   return ret;
 }
 
-static EC_GROUP *ec_group_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
-                                        const BIGNUM *b, BN_CTX *ctx) {
+EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
+                                 const BIGNUM *b, BN_CTX *ctx) {
   const EC_METHOD *meth = EC_GFp_mont_method();
   EC_GROUP *ret;
 
@@ -276,7 +276,7 @@ static EC_GROUP *ec_group_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
   }
 
   if (ret->meth->group_set_curve == 0) {
-    OPENSSL_PUT_ERROR(EC, ec_group_new_curve_GFp,
+    OPENSSL_PUT_ERROR(EC, EC_GROUP_new_curve_GFp,
                       ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
     return 0;
   }
@@ -287,6 +287,38 @@ static EC_GROUP *ec_group_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
   return ret;
 }
 
+int EC_GROUP_set_generator(EC_GROUP *group, const EC_POINT *generator,
+                           const BIGNUM *order, const BIGNUM *cofactor) {
+  if (group->generator == NULL) {
+    group->generator = EC_POINT_new(group);
+    if (group->generator == NULL) {
+      return 0;
+    }
+  }
+
+  if (!EC_POINT_copy(group->generator, generator)) {
+    return 0;
+  }
+
+  if (order != NULL) {
+    if (!BN_copy(&group->order, order)) {
+      return 0;
+    }
+  } else {
+    BN_zero(&group->order);
+  }
+
+  if (cofactor != NULL) {
+    if (!BN_copy(&group->cofactor, cofactor)) {
+      return 0;
+    }
+  } else {
+    BN_zero(&group->cofactor);
+  }
+
+  return 1;
+}
+
 static EC_GROUP *ec_group_new_from_data(const struct built_in_curve *curve) {
   EC_GROUP *group = NULL;
   EC_POINT *P = NULL;
@@ -322,7 +354,7 @@ static EC_GROUP *ec_group_new_from_data(const struct built_in_curve *curve) {
       goto err;
     }
   } else {
-    if ((group = ec_group_new_curve_GFp(p, a, b, ctx)) == NULL) {
+    if ((group = EC_GROUP_new_curve_GFp(p, a, b, ctx)) == NULL) {
       OPENSSL_PUT_ERROR(EC, ec_group_new_from_data, ERR_R_EC_LIB);
       goto err;
     }
diff --git a/src/crypto/err/ec.errordata b/src/crypto/err/ec.errordata
index 3b815c8..252f7ab 100644
--- a/src/crypto/err/ec.errordata
+++ b/src/crypto/err/ec.errordata
@@ -3,9 +3,11 @@ EC,function,100,EC_GROUP_copy
 EC,function,101,EC_GROUP_get_curve_GFp
 EC,function,102,EC_GROUP_get_degree
 EC,function,103,EC_GROUP_new_by_curve_name
+EC,function,166,EC_GROUP_new_curve_GFp
 EC,function,104,EC_KEY_check_key
 EC,function,105,EC_KEY_copy
 EC,function,106,EC_KEY_generate_key
+EC,function,165,EC_KEY_new_by_curve_name
 EC,function,107,EC_KEY_new_method
 EC,function,108,EC_KEY_set_public_key_affine_coordinates
 EC,function,109,EC_POINT_add
diff --git a/src/include/openssl/ec.h b/src/include/openssl/ec.h
index 633b11b..617cb19 100644
--- a/src/include/openssl/ec.h
+++ b/src/include/openssl/ec.h
@@ -286,6 +286,21 @@ OPENSSL_EXPORT int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r,
 
 /* Deprecated functions. */
 
+/* EC_GROUP_new_curve_GFp creates a new, arbitrary elliptic curve group based
+ * on the equation y² = x³ + a·x + b. It returns the new group or NULL on
+ * error. */
+OPENSSL_EXPORT EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p,
+                                                const BIGNUM *a,
+                                                const BIGNUM *b, BN_CTX *ctx);
+
+/* EC_GROUP_set_generator sets the generator for |group| to |generator|, which
+ * must have the given order and cofactor. This should only be used with
+ * |EC_GROUP| objects returned by |EC_GROUP_new_curve_GFp|. */
+OPENSSL_EXPORT int EC_GROUP_set_generator(EC_GROUP *group,
+                                          const EC_POINT *generator,
+                                          const BIGNUM *order,
+                                          const BIGNUM *cofactor);
+
 /* EC_GROUP_set_asn1_flag does nothing. */
 OPENSSL_EXPORT void EC_GROUP_set_asn1_flag(EC_GROUP *group, int flag);
 
@@ -381,6 +396,7 @@ OPENSSL_EXPORT void EC_GROUP_set_point_conversion_form(
 #define EC_F_ec_group_copy 163
 #define EC_F_nistp256_pre_comp_new 164
 #define EC_F_EC_KEY_new_by_curve_name 165
+#define EC_F_EC_GROUP_new_curve_GFp 166
 #define EC_R_BUFFER_TOO_SMALL 100
 #define EC_R_COORDINATES_OUT_OF_RANGE 101
 #define EC_R_D2I_ECPKPARAMETERS_FAILURE 102