openssh/compat.h
djm@openbsd.org 4ba0d54794 upstream: Improve strictness and control over RSA-SHA2 signature
In ssh, when an agent fails to return a RSA-SHA2 signature when
requested and falls back to RSA-SHA1 instead, retry the signature to
ensure that the public key algorithm sent in the SSH_MSG_USERAUTH
matches the one in the signature itself.

In sshd, strictly enforce that the public key algorithm sent in the
SSH_MSG_USERAUTH message matches what appears in the signature.

Make the sshd_config PubkeyAcceptedKeyTypes and
HostbasedAcceptedKeyTypes options control accepted signature algorithms
(previously they selected supported key types). This allows these
options to ban RSA-SHA1 in favour of RSA-SHA2.

Add new signature algorithms "rsa-sha2-256-cert-v01@openssh.com" and
"rsa-sha2-512-cert-v01@openssh.com" to force use of RSA-SHA2 signatures
with certificate keys.

feedback and ok markus@

OpenBSD-Commit-ID: c6e9f6d45eed8962ad502d315d7eaef32c419dde
2018-07-03 23:26:36 +10:00

74 lines
2.8 KiB
C

/* $OpenBSD: compat.h,v 1.52 2018/07/03 11:39:54 djm Exp $ */
/*
* Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef COMPAT_H
#define COMPAT_H
#define SSH_PROTO_UNKNOWN 0x00
#define SSH_PROTO_1 0x01
#define SSH_PROTO_1_PREFERRED 0x02
#define SSH_PROTO_2 0x04
#define SSH_BUG_UTF8TTYMODE 0x00000001
#define SSH_BUG_SIGTYPE 0x00000002
/* #define unused 0x00000004 */
/* #define unused 0x00000008 */
#define SSH_OLD_SESSIONID 0x00000010
/* #define unused 0x00000020 */
#define SSH_BUG_DEBUG 0x00000040
/* #define unused 0x00000080 */
#define SSH_BUG_IGNOREMSG 0x00000100
/* #define unused 0x00000200 */
#define SSH_BUG_PASSWORDPAD 0x00000400
#define SSH_BUG_SCANNER 0x00000800
#define SSH_BUG_BIGENDIANAES 0x00001000
#define SSH_BUG_RSASIGMD5 0x00002000
#define SSH_OLD_DHGEX 0x00004000
#define SSH_BUG_NOREKEY 0x00008000
/* #define unused 0x00010000 */
/* #define unused 0x00020000 */
/* #define unused 0x00040000 */
/* #define unused 0x00100000 */
#define SSH_BUG_EXTEOF 0x00200000
#define SSH_BUG_PROBE 0x00400000
/* #define unused 0x00800000 */
#define SSH_OLD_FORWARD_ADDR 0x01000000
/* #define unused 0x02000000 */
#define SSH_NEW_OPENSSH 0x04000000
#define SSH_BUG_DYNAMIC_RPORT 0x08000000
#define SSH_BUG_CURVE25519PAD 0x10000000
#define SSH_BUG_HOSTKEYS 0x20000000
#define SSH_BUG_DHGEX_LARGE 0x40000000
u_int compat_datafellows(const char *);
int proto_spec(const char *);
char *compat_cipher_proposal(char *);
char *compat_pkalg_proposal(char *);
char *compat_kex_proposal(char *);
extern int datafellows;
#endif