upstream: Remove support for loading HostBasedAuthentication keys

directly in ssh(1) and always use ssh-keysign.  This removes one of the few
remaining reasons why ssh(1) might be setuid.  ok markus@

OpenBSD-Commit-ID: 97f01e1448707129a20d75f86bad5d27c3cf0b7d
This commit is contained in:
dtucker@openbsd.org 2018-07-16 11:05:41 +00:00 committed by Damien Miller
parent 3eb7f1038d
commit 26efc2f5df
3 changed files with 9 additions and 39 deletions

35
ssh.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: ssh.c,v 1.484 2018/07/16 07:06:50 djm Exp $ */
/* $OpenBSD: ssh.c,v 1.485 2018/07/16 11:05:41 dtucker Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@ -1411,16 +1411,12 @@ main(int ac, char **av)
debug3("timeout: %d ms remain after connect", timeout_ms);
/*
* If we successfully made the connection, load the host private key
* in case we will need it later for hostbased
* authentication. This must be done before releasing extra
* privileges, because the file is only readable by root.
* If we cannot access the private keys, load the public keys
* instead and try to execute the ssh-keysign helper instead.
* If we successfully made the connection and we have hostbased auth
* enabled, load the public keys so we can later use the ssh-keysign
* helper to sign challenges.
*/
sensitive_data.nkeys = 0;
sensitive_data.keys = NULL;
sensitive_data.external_keysign = 0;
if (options.hostbased_authentication) {
sensitive_data.nkeys = 11;
sensitive_data.keys = xcalloc(sensitive_data.nkeys,
@ -1439,27 +1435,7 @@ main(int ac, char **av)
#define L_CERT(p,o) \
check_load(sshkey_load_cert(p, &(sensitive_data.keys[o])), p, "cert")
PRIV_START;
L_KEYCERT(KEY_ECDSA, _PATH_HOST_ECDSA_KEY_FILE, 1);
L_KEYCERT(KEY_ED25519, _PATH_HOST_ED25519_KEY_FILE, 2);
L_KEYCERT(KEY_RSA, _PATH_HOST_RSA_KEY_FILE, 3);
L_KEYCERT(KEY_DSA, _PATH_HOST_DSA_KEY_FILE, 4);
L_KEY(KEY_ECDSA, _PATH_HOST_ECDSA_KEY_FILE, 5);
L_KEY(KEY_ED25519, _PATH_HOST_ED25519_KEY_FILE, 6);
L_KEY(KEY_RSA, _PATH_HOST_RSA_KEY_FILE, 7);
L_KEY(KEY_DSA, _PATH_HOST_DSA_KEY_FILE, 8);
L_KEYCERT(KEY_XMSS, _PATH_HOST_XMSS_KEY_FILE, 9);
L_KEY(KEY_XMSS, _PATH_HOST_XMSS_KEY_FILE, 10);
PRIV_END;
if (options.hostbased_authentication == 1 &&
sensitive_data.keys[0] == NULL &&
sensitive_data.keys[5] == NULL &&
sensitive_data.keys[6] == NULL &&
sensitive_data.keys[7] == NULL &&
sensitive_data.keys[8] == NULL &&
sensitive_data.keys[9] == NULL &&
sensitive_data.keys[10] == NULL) {
if (options.hostbased_authentication == 1) {
L_CERT(_PATH_HOST_ECDSA_KEY_FILE, 1);
L_CERT(_PATH_HOST_ED25519_KEY_FILE, 2);
L_CERT(_PATH_HOST_RSA_KEY_FILE, 3);
@ -1470,7 +1446,6 @@ main(int ac, char **av)
L_PUBKEY(_PATH_HOST_DSA_KEY_FILE, 8);
L_CERT(_PATH_HOST_XMSS_KEY_FILE, 9);
L_PUBKEY(_PATH_HOST_XMSS_KEY_FILE, 10);
sensitive_data.external_keysign = 1;
}
}
/*

View File

@ -1,4 +1,4 @@
/* $OpenBSD: sshconnect.h,v 1.32 2018/02/10 09:25:35 djm Exp $ */
/* $OpenBSD: sshconnect.h,v 1.33 2018/07/16 11:05:41 dtucker Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
@ -28,7 +28,6 @@ typedef struct Sensitive Sensitive;
struct Sensitive {
struct sshkey **keys;
int nkeys;
int external_keysign;
};
struct addrinfo;

View File

@ -1,4 +1,4 @@
/* $OpenBSD: sshconnect2.c,v 1.280 2018/07/11 18:55:11 markus Exp $ */
/* $OpenBSD: sshconnect2.c,v 1.281 2018/07/16 11:05:41 dtucker Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Damien Miller. All rights reserved.
@ -1990,12 +1990,8 @@ userauth_hostbased(Authctxt *authctxt)
#ifdef DEBUG_PK
sshbuf_dump(b, stderr);
#endif
if (authctxt->sensitive->external_keysign)
r = ssh_keysign(private, &sig, &siglen,
sshbuf_ptr(b), sshbuf_len(b));
else if ((r = sshkey_sign(private, &sig, &siglen,
sshbuf_ptr(b), sshbuf_len(b), NULL, datafellows)) != 0)
debug("%s: sshkey_sign: %s", __func__, ssh_err(r));
r = ssh_keysign(private, &sig, &siglen,
sshbuf_ptr(b), sshbuf_len(b));
if (r != 0) {
error("sign using hostkey %s %s failed",
sshkey_ssh_name(private), fp);