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
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
/* openpgp-oids.c - OID helper for OpenPGP
* Copyright (C) 2011 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* GnuPG is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include <assert.h>
#include "util.h"
/* Helper for openpgp_oid_from_str. */
static size_t
make_flagged_int (unsigned long value, char *buf, size_t buflen)
{
int more = 0;
int shift;
/* fixme: figure out the number of bits in an ulong and start with
that value as shift (after making it a multiple of 7) a more
straigtforward implementation is to do it in reverse order using
a temporary buffer - saves a lot of compares */
for (more=0, shift=28; shift > 0; shift -= 7)
{
if (more || value >= (1<<shift))
{
buf[buflen++] = 0x80 | (value >> shift);
value -= (value >> shift) << shift;
more = 1;
}
}
buf[buflen++] = value;
return buflen;
}
/* Convert the OID given in dotted decimal form in STRING to an DER
* encoding and store it as an opaque value at R_MPI. The format of
* the DER encoded is not a regular ASN.1 object but the modified
* format as used by OpenPGP for the ECC curve description. On error
* the function returns and error code an NULL is stored at R_BUG.
* Note that scanning STRING stops at the first white space
* character. */
gpg_error_t
openpgp_oid_from_str (const char *string, gcry_mpi_t *r_mpi)
{
unsigned char *buf;
size_t buflen;
unsigned long val1, val;
const char *endp;
int arcno;
*r_mpi = NULL;
if (!string || !*string)
return gpg_error (GPG_ERR_INV_VALUE);
/* We can safely assume that the encoded OID is shorter than the string. */
buf = xtrymalloc (1 + strlen (string) + 2);
if (!buf)
return gpg_error_from_syserror ();
/* Save the first byte for the length. */
buflen = 1;
val1 = 0; /* Avoid compiler warning. */
arcno = 0;
do {
arcno++;
val = strtoul (string, (char**)&endp, 10);
if (!digitp (string) || !(*endp == '.' || !*endp))
{
xfree (buf);
return gpg_error (GPG_ERR_INV_OID_STRING);
}
if (*endp == '.')
string = endp+1;
if (arcno == 1)
{
if (val > 2)
break; /* Not allowed, error catched below. */
val1 = val;
}
else if (arcno == 2)
{ /* Need to combine the first two arcs in one octet. */
if (val1 < 2)
{
if (val > 39)
{
xfree (buf);
return gpg_error (GPG_ERR_INV_OID_STRING);
}
buf[buflen++] = val1*40 + val;
}
else
{
val += 80;
buflen = make_flagged_int (val, buf, buflen);
}
}
else
{
buflen = make_flagged_int (val, buf, buflen);
}
} while (*endp == '.');
if (arcno == 1 || buflen < 2 || buflen > 254 )
{ /* It is not possible to encode only the first arc. */
xfree (buf);
return gpg_error (GPG_ERR_INV_OID_STRING);
}
*buf = buflen - 1;
*r_mpi = gcry_mpi_set_opaque (NULL, buf, buflen * 8);
if (!*r_mpi)
{
xfree (buf);
return gpg_error_from_syserror ();
}
return 0;
}
/* Return a malloced string represenation of the OID in the opaque MPI
A. In case of an error NULL is returned and ERRNO is set. */
char *
openpgp_oid_to_str (gcry_mpi_t a)
{
const unsigned char *buf;
size_t length;
char *string, *p;
int n = 0;
unsigned long val, valmask;
valmask = (unsigned long)0xfe << (8 * (sizeof (valmask) - 1));
if (!a || !gcry_mpi_get_flag (a, GCRYMPI_FLAG_OPAQUE))
{
gpg_err_set_errno (EINVAL);
return NULL;
}
buf = gcry_mpi_get_opaque (a, &length);
length = (length+7)/8;
/* The first bytes gives the length; check consistency. */
if (!length || buf[0] != length -1)
{
gpg_err_set_errno (EINVAL);
return NULL;
}
/* Skip length byte. */
length--;
buf++;
/* To calculate the length of the string we can safely assume an
upper limit of 3 decimal characters per byte. Two extra bytes
account for the special first octect */
string = p = xtrymalloc (length*(1+3)+2+1);
if (!string)
return NULL;
if (!buf || !length)
{
*p = 0;
return string;
}
if (buf[0] < 40)
p += sprintf (p, "0.%d", buf[n]);
else if (buf[0] < 80)
p += sprintf (p, "1.%d", buf[n]-40);
else {
val = buf[n] & 0x7f;
while ( (buf[n]&0x80) && ++n < length )
{
if ( (val & valmask) )
goto badoid; /* Overflow. */
val <<= 7;
val |= buf[n] & 0x7f;
}
val -= 80;
sprintf (p, "2.%lu", val);
p += strlen (p);
}
for (n++; n < length; n++)
{
val = buf[n] & 0x7f;
while ( (buf[n]&0x80) && ++n < length )
{
if ( (val & valmask) )
goto badoid; /* Overflow. */
val <<= 7;
val |= buf[n] & 0x7f;
}
sprintf (p, ".%lu", val);
p += strlen (p);
}
*p = 0;
return string;
badoid:
/* Return a special OID (gnu.gnupg.badoid) to indicate the error
case. The OID is broken and thus we return one which can't do
any harm. Formally this does not need to be a bad OID but an OID
with an arc that can't be represented in a 32 bit word is more
than likely corrupt. */
xfree (string);
return xtrystrdup ("1.3.6.1.4.1.11591.2.12242973");
}
|
