diff options
Diffstat (limited to 'kexc25519.c')
| -rw-r--r-- | kexc25519.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/kexc25519.c b/kexc25519.c index 712dd523..acddcab3 100644 --- a/kexc25519.c +++ b/kexc25519.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kexc25519.c,v 1.11 2018/12/27 03:25:25 djm Exp $ */ +/* $OpenBSD: kexc25519.c,v 1.12 2019/01/21 09:49:37 djm Exp $ */ /* * Copyright (c) 2001, 2013 Markus Friedl. All rights reserved. * Copyright (c) 2010 Damien Miller. All rights reserved. @@ -64,14 +64,16 @@ kexc25519_shared_key(const u_char key[CURVE25519_SIZE], const u_char pub[CURVE25519_SIZE], struct sshbuf *out) { u_char shared_key[CURVE25519_SIZE]; + u_char zero[CURVE25519_SIZE]; int r; - /* Check for all-zero public key */ - explicit_bzero(shared_key, CURVE25519_SIZE); - if (timingsafe_bcmp(pub, shared_key, CURVE25519_SIZE) == 0) + crypto_scalarmult_curve25519(shared_key, key, pub); + + /* Check for all-zero shared secret */ + explicit_bzero(zero, CURVE25519_SIZE); + if (timingsafe_bcmp(zero, shared_key, CURVE25519_SIZE) == 0) return SSH_ERR_KEY_INVALID_EC_VALUE; - crypto_scalarmult_curve25519(shared_key, key, pub); #ifdef DEBUG_KEXECDH dump_digest("shared secret", shared_key, CURVE25519_SIZE); #endif |