Fix for processing of EC public key

Prevents segmentation fault while reading EC private key without public key.
Generates missing EC public key when reading EC private key.

Refer to these OpenSSL commits:
1f2b943254ce590867717375e4f364860a9b7154
2083f7c465d07867dd9867b8742bb71c03d1f203

Reported on GitHub https://github.com/libressl-portable/portable/issues/395
by Anton Bukov (@k06a) .

ok beck@

1 files changed, 8 insertions, 6 deletions

diff --git a/src/lib/libcrypto/ec/ec_ameth.c b/src/lib/libcrypto/ec/ec_ameth.c
index 8d0cdb733b..0932f1e3c9 100644
--- a/src/lib/libcrypto/ec/ec_ameth.c
+++ b/src/lib/libcrypto/ec/ec_ameth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ec_ameth.c,v 1.18 2017/01/29 17:49:23 beck Exp $ */
+/* $OpenBSD: ec_ameth.c,v 1.19 2018/03/12 13:14:21 inoguchi Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -433,13 +433,15 @@ do_EC_KEY_print(BIO * bp, const EC_KEY * x, int off, int ktype)
         }
         if (ktype > 0) {
                 public_key = EC_KEY_get0_public_key(x);
-                if ((pub_key = EC_POINT_point2bn(group, public_key,
+                if (public_key != NULL) {
+                        if ((pub_key = EC_POINT_point2bn(group, public_key,
                             EC_KEY_get_conv_form(x), NULL, ctx)) == NULL) {
-                        reason = ERR_R_EC_LIB;
-                        goto err;
+                                reason = ERR_R_EC_LIB;
+                                goto err;
+                        }
+                        if (pub_key)
+                                buf_len = (size_t) BN_num_bytes(pub_key);
                 }
-                if (pub_key)
-                        buf_len = (size_t) BN_num_bytes(pub_key);
         }
         if (ktype == 2) {
                 priv_key = EC_KEY_get0_private_key(x);