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
|
// SPDX-License-Identifier: GPL-2.0-or-later
/* ASN.1 Object identifier (OID) registry
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/module.h>
#include <linux/export.h>
#include <linux/oid_registry.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/bug.h>
#include <linux/asn1.h>
#include "oid_registry_data.c"
MODULE_DESCRIPTION("OID Registry");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
/**
* look_up_OID - Find an OID registration for the specified data
* @data: Binary representation of the OID
* @datasize: Size of the binary representation
*/
enum OID look_up_OID(const void *data, size_t datasize)
{
const unsigned char *octets = data;
enum OID oid;
unsigned char xhash;
unsigned i, j, k, hash;
size_t len;
/* Hash the OID data */
hash = datasize - 1;
for (i = 0; i < datasize; i++)
hash += octets[i] * 33;
hash = (hash >> 24) ^ (hash >> 16) ^ (hash >> 8) ^ hash;
hash &= 0xff;
/* Binary search the OID registry. OIDs are stored in ascending order
* of hash value then ascending order of size and then in ascending
* order of reverse value.
*/
i = 0;
k = OID__NR;
while (i < k) {
j = (i + k) / 2;
xhash = oid_search_table[j].hash;
if (xhash > hash) {
k = j;
continue;
}
if (xhash < hash) {
i = j + 1;
continue;
}
oid = oid_search_table[j].oid;
len = oid_index[oid + 1] - oid_index[oid];
if (len > datasize) {
k = j;
continue;
}
if (len < datasize) {
i = j + 1;
continue;
}
/* Variation is most likely to be at the tail end of the
* OID, so do the comparison in reverse.
*/
while (len > 0) {
unsigned char a = oid_data[oid_index[oid] + --len];
unsigned char b = octets[len];
if (a > b) {
k = j;
goto next;
}
if (a < b) {
i = j + 1;
goto next;
}
}
return oid;
next:
;
}
return OID__NR;
}
EXPORT_SYMBOL_GPL(look_up_OID);
/**
* parse_OID - Parse an OID from a bytestream
* @data: Binary representation of the header + OID
* @datasize: Size of the binary representation
* @oid: Pointer to oid to return result
*
* Parse an OID from a bytestream that holds the OID in the format
* ASN1_OID | length | oid. The length indicator must equal to datasize - 2.
* -EBADMSG is returned if the bytestream is too short.
*/
int parse_OID(const void *data, size_t datasize, enum OID *oid)
{
const unsigned char *v = data;
/* we need 2 bytes of header and at least 1 byte for oid */
if (datasize < 3 || v[0] != ASN1_OID || v[1] != datasize - 2)
return -EBADMSG;
*oid = look_up_OID(data + 2, datasize - 2);
return 0;
}
EXPORT_SYMBOL_GPL(parse_OID);
/*
* sprint_OID - Print an Object Identifier into a buffer
* @data: The encoded OID to print
* @datasize: The size of the encoded OID
* @buffer: The buffer to render into
* @bufsize: The size of the buffer
*
* The OID is rendered into the buffer in "a.b.c.d" format and the number of
* bytes is returned. -EBADMSG is returned if the data could not be intepreted
* and -ENOBUFS if the buffer was too small.
*/
int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize)
{
const unsigned char *v = data, *end = v + datasize;
unsigned long num;
unsigned char n;
size_t ret;
int count;
if (v >= end)
goto bad;
n = *v++;
ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40);
if (count >= bufsize)
return -ENOBUFS;
buffer += count;
bufsize -= count;
while (v < end) {
num = 0;
n = *v++;
if (!(n & 0x80)) {
num = n;
} else {
num = n & 0x7f;
do {
if (v >= end)
goto bad;
n = *v++;
num <<= 7;
num |= n & 0x7f;
} while (n & 0x80);
}
ret += count = snprintf(buffer, bufsize, ".%lu", num);
if (count >= bufsize)
return -ENOBUFS;
buffer += count;
bufsize -= count;
}
return ret;
bad:
snprintf(buffer, bufsize, "(bad)");
return -EBADMSG;
}
EXPORT_SYMBOL_GPL(sprint_oid);
/**
* sprint_OID - Print an Object Identifier into a buffer
* @oid: The OID to print
* @buffer: The buffer to render into
* @bufsize: The size of the buffer
*
* The OID is rendered into the buffer in "a.b.c.d" format and the number of
* bytes is returned.
*/
int sprint_OID(enum OID oid, char *buffer, size_t bufsize)
{
int ret;
BUG_ON(oid >= OID__NR);
ret = sprint_oid(oid_data + oid_index[oid],
oid_index[oid + 1] - oid_index[oid],
buffer, bufsize);
BUG_ON(ret == -EBADMSG);
return ret;
}
EXPORT_SYMBOL_GPL(sprint_OID);
|
