Mercurial > dropbear
annotate dss.h @ 1788:1fc0012b9c38
Fix handling of replies to global requests (#112)
The current code assumes that all global requests want / need a reply.
This isn't always true and the request itself indicates if it wants a
reply or not.
It causes a specific problem with [email protected] messages.
These are sent by OpenSSH after authentication to inform the client of
potential other host keys for the host. This can be used to add a new
type of host key or to rotate host keys.
The initial information message from the server is sent as a global
request, but with want_reply set to false. This means that the server
doesn't expect an answer to this message. Instead the client needs to
send a prove request as a reply if it wants to receive proof of
ownership for the host keys.
The bug doesn't cause any current problems with due to how OpenSSH
treats receiving the failure message. It instead treats it as a
keepalive message and further ignores it.
Arguably this is a protocol violation though of Dropbear and it is only
accidental that it doesn't cause a problem with OpenSSH.
The bug was found when adding host keys support to libssh, which is more
strict protocol wise and treats the unexpected failure message an error,
also see https://gitlab.com/libssh/libssh-mirror/-/merge_requests/145
for more information.
The fix here is to honor the want_reply flag in the global request and
to only send a reply if the other side expects a reply.
author | Dirkjan Bussink <d.bussink@gmail.com> |
---|---|
date | Thu, 10 Dec 2020 16:13:13 +0100 |
parents | ba6fc7afe1c5 |
children |
rev | line source |
---|---|
4
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
1 /* |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
2 * Dropbear - a SSH2 server |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
3 * |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
4 * Copyright (c) 2002,2003 Matt Johnston |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
5 * All rights reserved. |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
6 * |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
7 * Permission is hereby granted, free of charge, to any person obtaining a copy |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
8 * of this software and associated documentation files (the "Software"), to deal |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
9 * in the Software without restriction, including without limitation the rights |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
11 * copies of the Software, and to permit persons to whom the Software is |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
12 * furnished to do so, subject to the following conditions: |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
13 * |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
14 * The above copyright notice and this permission notice shall be included in |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
15 * all copies or substantial portions of the Software. |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
16 * |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
23 * SOFTWARE. */ |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
24 |
1036
deed0571cacc
DROPBEAR_ prefix for include guards to avoid collisions
Thorsten Horstmann <thorsten.horstmann@web.de>
parents:
794
diff
changeset
|
25 #ifndef DROPBEAR_DSS_H_ |
deed0571cacc
DROPBEAR_ prefix for include guards to avoid collisions
Thorsten Horstmann <thorsten.horstmann@web.de>
parents:
794
diff
changeset
|
26 #define DROPBEAR_DSS_H_ |
4
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
27 |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
28 #include "includes.h" |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
29 #include "buffer.h" |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
30 |
1295
750ec4ec4cbe
Convert #ifdef to #if, other build changes
Matt Johnston <matt@ucc.asn.au>
parents:
1036
diff
changeset
|
31 #if DROPBEAR_DSS |
4
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
32 |
1674
ba6fc7afe1c5
use sigtype where appropriate
Matt Johnston <matt@ucc.asn.au>
parents:
1459
diff
changeset
|
33 typedef struct dropbear_DSS_Key { |
4
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
34 |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
35 mp_int* p; |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
36 mp_int* q; |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
37 mp_int* g; |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
38 mp_int* y; |
584 | 39 /* x is the private part */ |
4
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
40 mp_int* x; |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
41 |
586
b50f0107e505
Rename rsa_key to dropbear_rsa_key (and same for dss too) so
Matt Johnston <matt@ucc.asn.au>
parents:
584
diff
changeset
|
42 } dropbear_dss_key; |
4
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
43 |
1413 | 44 #define DSS_P_BITS 1024 |
45 #define DSS_Q_BITS 160 | |
46 | |
1459
06d52bcb8094
Pointer parameter could be declared as pointing to const
Francois Perrad <francois.perrad@gadz.org>
parents:
1413
diff
changeset
|
47 void buf_put_dss_sign(buffer* buf, const dropbear_dss_key *key, const buffer *data_buf); |
1295
750ec4ec4cbe
Convert #ifdef to #if, other build changes
Matt Johnston <matt@ucc.asn.au>
parents:
1036
diff
changeset
|
48 #if DROPBEAR_SIGNKEY_VERIFY |
1459
06d52bcb8094
Pointer parameter could be declared as pointing to const
Francois Perrad <francois.perrad@gadz.org>
parents:
1413
diff
changeset
|
49 int buf_dss_verify(buffer* buf, const dropbear_dss_key *key, const buffer *data_buf); |
4
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
50 #endif |
586
b50f0107e505
Rename rsa_key to dropbear_rsa_key (and same for dss too) so
Matt Johnston <matt@ucc.asn.au>
parents:
584
diff
changeset
|
51 int buf_get_dss_pub_key(buffer* buf, dropbear_dss_key *key); |
b50f0107e505
Rename rsa_key to dropbear_rsa_key (and same for dss too) so
Matt Johnston <matt@ucc.asn.au>
parents:
584
diff
changeset
|
52 int buf_get_dss_priv_key(buffer* buf, dropbear_dss_key *key); |
1459
06d52bcb8094
Pointer parameter could be declared as pointing to const
Francois Perrad <francois.perrad@gadz.org>
parents:
1413
diff
changeset
|
53 void buf_put_dss_pub_key(buffer* buf, const dropbear_dss_key *key); |
06d52bcb8094
Pointer parameter could be declared as pointing to const
Francois Perrad <francois.perrad@gadz.org>
parents:
1413
diff
changeset
|
54 void buf_put_dss_priv_key(buffer* buf, const dropbear_dss_key *key); |
586
b50f0107e505
Rename rsa_key to dropbear_rsa_key (and same for dss too) so
Matt Johnston <matt@ucc.asn.au>
parents:
584
diff
changeset
|
55 void dss_key_free(dropbear_dss_key *key); |
4
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
56 |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
57 #endif /* DROPBEAR_DSS */ |
fe6bca95afa7
Makefile.in contains updated files required
Matt Johnston <matt@ucc.asn.au>
parents:
diff
changeset
|
58 |
1036
deed0571cacc
DROPBEAR_ prefix for include guards to avoid collisions
Thorsten Horstmann <thorsten.horstmann@web.de>
parents:
794
diff
changeset
|
59 #endif /* DROPBEAR_DSS_H_ */ |