3 files changed, 11 insertions, 4 deletions

diff --git a/src/lib/libcrypto/ecdh/ecdh.h b/src/lib/libcrypto/ecdh/ecdh.h
index e1cc8404d0..ccc1312fd8 100644
--- a/src/lib/libcrypto/ecdh/ecdh.h
+++ b/src/lib/libcrypto/ecdh/ecdh.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ecdh.h,v 1.4 2015/09/13 11:49:44 jsing Exp $ */
+/* $OpenBSD: ecdh.h,v 1.5 2015/09/13 12:03:07 jsing Exp $ */
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
@@ -91,6 +91,7 @@ void ECDH_set_default_method(const ECDH_METHOD *);
 const ECDH_METHOD *ECDH_get_default_method(void);
 int ECDH_set_method(EC_KEY *, const ECDH_METHOD *);
 
+int ECDH_size(const EC_KEY *ecdh);
 int ECDH_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
     EC_KEY *ecdh,
     void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen));
diff --git a/src/lib/libcrypto/ecdh/ech_lib.c b/src/lib/libcrypto/ecdh/ech_lib.c
index 579dfc4b4f..bb70d2d95f 100644
--- a/src/lib/libcrypto/ecdh/ech_lib.c
+++ b/src/lib/libcrypto/ecdh/ech_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ech_lib.c,v 1.10 2015/09/13 10:46:20 jsing Exp $ */
+/* $OpenBSD: ech_lib.c,v 1.11 2015/09/13 12:03:07 jsing Exp $ */
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
@@ -239,3 +239,9 @@ ECDH_get_ex_data(EC_KEY *d, int idx)
                 return NULL;
         return (CRYPTO_get_ex_data(&ecdh->ex_data, idx));
 }
+
+int
+ECDH_size(const EC_KEY *d)
+{
+        return ((EC_GROUP_get_degree(EC_KEY_get0_group(d)) + 7) / 8);
+}
diff --git a/src/lib/libcrypto/ecdh/ech_ossl.c b/src/lib/libcrypto/ecdh/ech_ossl.c
index 746eb12ea3..7956edc0e6 100644
--- a/src/lib/libcrypto/ecdh/ech_ossl.c
+++ b/src/lib/libcrypto/ecdh/ech_ossl.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ech_ossl.c,v 1.11 2015/09/13 11:49:44 jsing Exp $ */
+/* $OpenBSD: ech_ossl.c,v 1.12 2015/09/13 12:03:07 jsing Exp $ */
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
@@ -166,7 +166,7 @@ ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
         }
 #endif
 
-        buflen = (EC_GROUP_get_degree(group) + 7)/8;
+        buflen = ECDH_size(ecdh);
         len = BN_num_bytes(x);
         if (len > buflen) {
                 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_INTERNAL_ERROR);