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
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2009 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#include "CephxSessionHandler.h"
#include "CephxProtocol.h"
#include <errno.h>
#include <sstream>
#include "common/config.h"
#include "include/ceph_features.h"
#include "msg/Message.h"
#define dout_subsys ceph_subsys_auth
int CephxSessionHandler::_calc_signature(Message *m, uint64_t *psig)
{
const ceph_msg_header& header = m->get_header();
const ceph_msg_footer& footer = m->get_footer();
if (!HAVE_FEATURE(features, CEPHX_V2)) {
// legacy pre-mimic behavior for compatibility
// optimized signature calculation
// - avoid temporary allocated buffers from encode_encrypt[_enc_bl]
// - skip the leading 4 byte wrapper from encode_encrypt
struct {
__u8 v;
ceph_le64 magic;
ceph_le32 len;
ceph_le32 header_crc;
ceph_le32 front_crc;
ceph_le32 middle_crc;
ceph_le32 data_crc;
} __attribute__ ((packed)) sigblock = {
1, init_le64(AUTH_ENC_MAGIC), init_le32(4*4),
init_le32(header.crc), init_le32(footer.front_crc),
init_le32(footer.middle_crc), init_le32(footer.data_crc)
};
char exp_buf[CryptoKey::get_max_outbuf_size(sizeof(sigblock))];
try {
const CryptoKey::in_slice_t in {
sizeof(sigblock),
reinterpret_cast<const unsigned char*>(&sigblock)
};
const CryptoKey::out_slice_t out {
sizeof(exp_buf),
reinterpret_cast<unsigned char*>(&exp_buf)
};
key.encrypt(cct, in, out);
} catch (std::exception& e) {
lderr(cct) << __func__ << " failed to encrypt signature block" << dendl;
return -1;
}
*psig = *reinterpret_cast<ceph_le64*>(exp_buf);
} else {
// newer mimic+ signatures
struct {
ceph_le32 header_crc;
ceph_le32 front_crc;
ceph_le32 front_len;
ceph_le32 middle_crc;
ceph_le32 middle_len;
ceph_le32 data_crc;
ceph_le32 data_len;
ceph_le32 seq_lower_word;
} __attribute__ ((packed)) sigblock = {
init_le32(header.crc),
init_le32(footer.front_crc),
init_le32(header.front_len),
init_le32(footer.middle_crc),
init_le32(header.middle_len),
init_le32(footer.data_crc),
init_le32(header.data_len),
init_le32(header.seq)
};
char exp_buf[CryptoKey::get_max_outbuf_size(sizeof(sigblock))];
try {
const CryptoKey::in_slice_t in {
sizeof(sigblock),
reinterpret_cast<const unsigned char*>(&sigblock)
};
const CryptoKey::out_slice_t out {
sizeof(exp_buf),
reinterpret_cast<unsigned char*>(&exp_buf)
};
key.encrypt(cct, in, out);
} catch (std::exception& e) {
lderr(cct) << __func__ << " failed to encrypt signature block" << dendl;
return -1;
}
struct enc {
ceph_le64 a, b, c, d;
} *penc = reinterpret_cast<enc*>(exp_buf);
*psig = penc->a ^ penc->b ^ penc->c ^ penc->d;
}
ldout(cct, 10) << __func__ << " seq " << m->get_seq()
<< " front_crc_ = " << footer.front_crc
<< " middle_crc = " << footer.middle_crc
<< " data_crc = " << footer.data_crc
<< " sig = " << *psig
<< dendl;
return 0;
}
int CephxSessionHandler::sign_message(Message *m)
{
// If runtime signing option is off, just return success without signing.
if (!cct->_conf->cephx_sign_messages) {
return 0;
}
uint64_t sig;
int r = _calc_signature(m, &sig);
if (r < 0)
return r;
ceph_msg_footer& f = m->get_footer();
f.sig = sig;
f.flags = (unsigned)f.flags | CEPH_MSG_FOOTER_SIGNED;
ldout(cct, 20) << "Putting signature in client message(seq # " << m->get_seq()
<< "): sig = " << sig << dendl;
return 0;
}
int CephxSessionHandler::check_message_signature(Message *m)
{
// If runtime signing option is off, just return success without checking signature.
if (!cct->_conf->cephx_sign_messages) {
return 0;
}
if ((features & CEPH_FEATURE_MSG_AUTH) == 0) {
// it's fine, we didn't negotiate this feature.
return 0;
}
uint64_t sig;
int r = _calc_signature(m, &sig);
if (r < 0)
return r;
if (sig != m->get_footer().sig) {
// Should have been signed, but signature check failed. PLR
if (!(m->get_footer().flags & CEPH_MSG_FOOTER_SIGNED)) {
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << " Sender did not set CEPH_MSG_FOOTER_SIGNED." << dendl;
}
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << " Message signature does not match contents." << dendl;
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << "Signature on message:" << dendl;
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << " sig: " << m->get_footer().sig << dendl;
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << "Locally calculated signature:" << dendl;
ldout(cct, 0) << "SIGN: MSG " << m->get_seq() << " sig_check:" << sig << dendl;
// For the moment, printing an error message to the log and
// returning failure is sufficient. In the long term, we should
// probably have code parsing the log looking for this kind of
// security failure, particularly when there are large numbers of
// them, since the latter is a potential sign of an attack. PLR
ldout(cct, 0) << "Signature failed." << dendl;
return (SESSION_SIGNATURE_FAILURE);
}
return 0;
}
|
