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
183
184
185
186
187
188
189
190
191
|
/*
* pgp-pubdec.c
* Decrypt public-key encrypted session key.
*
* Copyright (c) 2005 Marko Kreen
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*
* $PostgreSQL: pgsql/contrib/pgcrypto/pgp-pubdec.c,v 1.2 2005/07/10 15:37:03 momjian Exp $
*/
#include <postgres.h>
#include "px.h"
#include "mbuf.h"
#include "pgp.h"
/*
* padded msg = 02 || PS || 00 || M
* PS - pad bytes
* M - msg
*/
static uint8 *
check_eme_pkcs1_v15(uint8 *data, int len)
{
uint8 *data_end = data + len;
uint8 *p = data;
int rnd = 0;
if (len < 1 + 8 + 1)
return NULL;
if (*p++ != 2)
return NULL;
while (p < data_end && *p) {
p++;
rnd++;
}
if (p == data_end)
return NULL;
if (*p != 0)
return NULL;
if (rnd < 8)
return NULL;
return p + 1;
}
/*
* secret message: 1 byte algo, sesskey, 2 byte cksum
* ignore algo in cksum
*/
static int
control_cksum(uint8 *msg, int msglen)
{
int i;
unsigned my_cksum, got_cksum;
if (msglen < 3)
return PXE_PGP_CORRUPT_DATA;
my_cksum = 0;
for (i = 1; i < msglen - 2; i++)
my_cksum += msg[i];
my_cksum &= 0xFFFF;
got_cksum = ((unsigned)(msg[msglen-2]) << 8) + msg[msglen-1];
if (my_cksum != got_cksum) {
px_debug("pubenc cksum failed");
return PXE_PGP_CORRUPT_DATA;
}
return 0;
}
/* key id is missing - user is expected to try all keys */
static const uint8
any_key[] = {0, 0, 0, 0, 0, 0, 0, 0};
int
pgp_parse_pubenc_sesskey(PGP_Context *ctx, PullFilter *pkt)
{
int ver;
int algo;
int res;
uint8 key_id[8];
PGP_MPI *c1, *c2;
PGP_PubKey *pk;
uint8 *msg;
int msglen;
PGP_MPI *m;
pk = ctx->pub_key;
if (pk == NULL) {
px_debug("no pubkey?");
return PXE_BUG;
}
if (!pk->elg_p || !pk->elg_g || !pk->elg_y || !pk->elg_x) {
px_debug("seckey not loaded?");
return PXE_BUG;
}
GETBYTE(pkt, ver);
if (ver != 3) {
px_debug("unknown pubenc_sesskey pkt ver=%d", ver);
return PXE_PGP_CORRUPT_DATA;
}
/*
* check if keyid's match - user-friendly msg
*/
res = pullf_read_fixed(pkt, 8, key_id);
if (res < 0)
return res;
if (memcmp(key_id, any_key, 8) != 0
&& memcmp(key_id, pk->key_id, 8) != 0)
{
px_debug("key_id's does not match");
return PXE_PGP_WRONG_KEYID;
}
GETBYTE(pkt, algo);
if (algo != PGP_PUB_ELG_ENCRYPT)
{
px_debug("unknown public-key algo=%d", algo);
if (algo == PGP_PUB_RSA_ENCRYPT || algo == PGP_PUB_RSA_ENCRYPT_SIGN)
return PXE_PGP_RSA_UNSUPPORTED;
else
return PXE_PGP_UNKNOWN_PUBALGO;
}
/*
* read elgamal encrypted data
*/
res = pgp_mpi_read(pkt, &c1);
if (res < 0)
return res;
res = pgp_mpi_read(pkt, &c2);
if (res < 0)
return res;
/*
* decrypt
*/
res = pgp_elgamal_decrypt(pk, c1, c2, &m);
if (res < 0)
return res;
/*
* extract message
*/
msg = check_eme_pkcs1_v15(m->data, m->bytes);
if (msg == NULL) {
px_debug("check_eme_pkcs1_v15 failed");
return PXE_PGP_CORRUPT_DATA;
}
msglen = m->bytes - (msg - m->data);
res = control_cksum(msg, msglen);
if (res < 0)
return res;
/*
* got sesskey
*/
ctx->cipher_algo = *msg;
ctx->sess_key_len = msglen - 3;
memcpy(ctx->sess_key, msg + 1, ctx->sess_key_len);
return pgp_expect_packet_end(pkt);
}
|
