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| author | djm@openbsd.org <djm@openbsd.org> | 2019-01-21 09:49:37 +0000 |
|---|---|---|
| committer | Damien Miller <djm@mindrot.org> | 2019-01-21 21:46:05 +1100 |
| commit | f3ebaffd8714be31d4345f90af64992de4b3bba2 (patch) | |
| tree | d0a73c727dc9aaf21842426908581531f4a7d741 /kexc25519.c | |
| parent | 9d1a9771d0ad3a83af733bf3d2650b53f43c269f (diff) | |
| download | openssh-git-f3ebaffd8714be31d4345f90af64992de4b3bba2.tar.gz | |
upstream: fix all-zero check in kexc25519_shared_key
from markus@ ok djm@
OpenBSD-Commit-ID: 60b1d364e0d9d34d1d1ef1620cb92e36cf06712d
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 |