Only check for key truncation if no KDF function is being used.

ok beck@ miod@

2 files changed, 8 insertions, 8 deletions

diff --git a/src/lib/libcrypto/ecdh/ech_key.c b/src/lib/libcrypto/ecdh/ech_key.c
index 7202c497cf..e695b0b9ad 100644
--- a/src/lib/libcrypto/ecdh/ech_key.c
+++ b/src/lib/libcrypto/ecdh/ech_key.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ech_key.c,v 1.4 2015/09/13 12:27:14 jsing Exp $ */
+/* $OpenBSD: ech_key.c,v 1.5 2015/09/13 14:11:57 jsing Exp $ */
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
@@ -162,7 +162,7 @@ ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
                 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_INTERNAL_ERROR);
                 goto err;
         }
-        if (outlen < buflen) {
+        if (KDF == NULL && outlen < buflen) {
                 /* The resulting key would be truncated. */
                 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_KEY_TRUNCATION);
                 goto err;
@@ -178,14 +178,14 @@ ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
                 goto err;
         }
 
-        if (KDF != 0) {
+        if (KDF != NULL) {
                 if (KDF(buf, buflen, out, &outlen) == NULL) {
                         ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_KDF_FAILED);
                         goto err;
                 }
                 ret = outlen;
         } else {
-                /* No KDF, just copy as much as we can and zero the rest. */
+                /* No KDF, just copy out the key and zero the rest. */
                 if (outlen > buflen) {
                         memset(out + buflen, 0, outlen - buflen);
                         outlen = buflen;
diff --git a/src/lib/libssl/src/crypto/ecdh/ech_key.c b/src/lib/libssl/src/crypto/ecdh/ech_key.c
index 7202c497cf..e695b0b9ad 100644
--- a/src/lib/libssl/src/crypto/ecdh/ech_key.c
+++ b/src/lib/libssl/src/crypto/ecdh/ech_key.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ech_key.c,v 1.4 2015/09/13 12:27:14 jsing Exp $ */
+/* $OpenBSD: ech_key.c,v 1.5 2015/09/13 14:11:57 jsing Exp $ */
 /* ====================================================================
  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
  *
@@ -162,7 +162,7 @@ ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
                 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_INTERNAL_ERROR);
                 goto err;
         }
-        if (outlen < buflen) {
+        if (KDF == NULL && outlen < buflen) {
                 /* The resulting key would be truncated. */
                 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_KEY_TRUNCATION);
                 goto err;
@@ -178,14 +178,14 @@ ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
                 goto err;
         }
 
-        if (KDF != 0) {
+        if (KDF != NULL) {
                 if (KDF(buf, buflen, out, &outlen) == NULL) {
                         ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_KDF_FAILED);
                         goto err;
                 }
                 ret = outlen;
         } else {
-                /* No KDF, just copy as much as we can and zero the rest. */
+                /* No KDF, just copy out the key and zero the rest. */
                 if (outlen > buflen) {
                         memset(out + buflen, 0, outlen - buflen);
                         outlen = buflen;