1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
// SPDX-License-Identifier: LGPL-2.1-or-later
/*
* ssh plugin utilities
*
* Copyright (C) 2016-2024 Milan Broz
* Copyright (C) 2020-2024 Vojtech Trefny
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <libssh/libssh.h>
#include <libssh/sftp.h>
#include <fcntl.h>
#include <libcryptsetup.h>
#include "ssh-utils.h"
#include "../lib/nls.h"
#define KEYFILE_LENGTH_MAX 8192
int sshplugin_download_password(struct crypt_device *cd, ssh_session ssh,
const char *path, char **password, size_t *password_len)
{
char *pass = NULL;
size_t pass_len;
int r;
sftp_attributes sftp_attr = NULL;
sftp_session sftp = NULL;
sftp_file file = NULL;
sftp = sftp_new(ssh);
if (!sftp) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Cannot create sftp session: "));
r = SSH_FX_FAILURE;
goto out;
}
r = sftp_init(sftp);
if (r != SSH_OK) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Cannot init sftp session: "));
goto out;
}
file = sftp_open(sftp, path, O_RDONLY, 0);
if (!file) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Cannot open sftp session: "));
r = SSH_FX_FAILURE;
goto out;
}
sftp_attr = sftp_fstat(file);
if (!sftp_attr) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Cannot stat sftp file: "));
r = SSH_FX_FAILURE;
goto out;
}
pass_len = sftp_attr->size > KEYFILE_LENGTH_MAX ? KEYFILE_LENGTH_MAX : sftp_attr->size;
pass = malloc(pass_len);
if (!pass) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Not enough memory.\n"));
r = SSH_FX_FAILURE;
goto out;
}
r = sftp_read(file, pass, pass_len);
if (r < 0 || (size_t)r != pass_len) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Cannot read remote key: "));
r = SSH_FX_FAILURE;
goto out;
}
*password = pass;
*password_len = pass_len;
r = SSH_OK;
out:
if (r != SSH_OK) {
crypt_log(cd, CRYPT_LOG_ERROR, ssh_get_error(ssh));
crypt_log(cd, CRYPT_LOG_ERROR, "\n");
free(pass);
}
if (sftp_attr)
sftp_attributes_free(sftp_attr);
if (file)
sftp_close(file);
if (sftp)
sftp_free(sftp);
return r == SSH_OK ? 0 : -EINVAL;
}
ssh_session sshplugin_session_init(struct crypt_device *cd, const char *host, const char *user)
{
int r, port = 22;
ssh_session ssh = ssh_new();
if (!ssh)
return NULL;
ssh_options_set(ssh, SSH_OPTIONS_HOST, host);
ssh_options_set(ssh, SSH_OPTIONS_USER, user);
ssh_options_set(ssh, SSH_OPTIONS_PORT, &port);
crypt_log(cd, CRYPT_LOG_NORMAL, "SSH token initiating ssh session.\n");
r = ssh_connect(ssh);
if (r != SSH_OK) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Connection failed: "));
goto out;
}
#if HAVE_DECL_SSH_SESSION_IS_KNOWN_SERVER
r = ssh_session_is_known_server(ssh);
#else
r = ssh_is_server_known(ssh);
#endif
if (r != SSH_SERVER_KNOWN_OK) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Server not known: "));
r = SSH_AUTH_ERROR;
goto out;
}
r = SSH_OK;
/* initialise list of authentication methods. yes, according to official libssh docs... */
ssh_userauth_none(ssh, NULL);
out:
if (r != SSH_OK) {
crypt_log(cd, CRYPT_LOG_ERROR, ssh_get_error(ssh));
crypt_log(cd, CRYPT_LOG_ERROR, "\n");
ssh_disconnect(ssh);
ssh_free(ssh);
ssh = NULL;
}
return ssh;
}
int sshplugin_public_key_auth(struct crypt_device *cd, ssh_session ssh, const ssh_key pkey)
{
int r;
crypt_log(cd, CRYPT_LOG_DEBUG, "Trying public key authentication method.\n");
if (!(ssh_userauth_list(ssh, NULL) & SSH_AUTH_METHOD_PUBLICKEY)) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Public key auth method not allowed on host.\n"));
return SSH_AUTH_ERROR;
}
r = ssh_userauth_try_publickey(ssh, NULL, pkey);
if (r == SSH_AUTH_SUCCESS) {
crypt_log(cd, CRYPT_LOG_DEBUG, "Public key method accepted.\n");
r = ssh_userauth_publickey(ssh, NULL, pkey);
}
if (r != SSH_AUTH_SUCCESS) {
crypt_log(cd, CRYPT_LOG_ERROR, _("Public key authentication error: "));
crypt_log(cd, CRYPT_LOG_ERROR, ssh_get_error(ssh));
crypt_log(cd, CRYPT_LOG_ERROR, "\n");
}
return r;
}
|
