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-rw-r--r--lib/oid_registry.c170
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diff --git a/lib/oid_registry.c b/lib/oid_registry.c
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1/* ASN.1 Object identifier (OID) registry
2 *
3 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#include <linux/export.h>
13#include <linux/oid_registry.h>
14#include <linux/kernel.h>
15#include <linux/errno.h>
16#include <linux/bug.h>
17#include "oid_registry_data.c"
18
19/**
20 * look_up_OID - Find an OID registration for the specified data
21 * @data: Binary representation of the OID
22 * @datasize: Size of the binary representation
23 */
24enum OID look_up_OID(const void *data, size_t datasize)
25{
26 const unsigned char *octets = data;
27 enum OID oid;
28 unsigned char xhash;
29 unsigned i, j, k, hash;
30 size_t len;
31
32 /* Hash the OID data */
33 hash = datasize - 1;
34
35 for (i = 0; i < datasize; i++)
36 hash += octets[i] * 33;
37 hash = (hash >> 24) ^ (hash >> 16) ^ (hash >> 8) ^ hash;
38 hash &= 0xff;
39
40 /* Binary search the OID registry. OIDs are stored in ascending order
41 * of hash value then ascending order of size and then in ascending
42 * order of reverse value.
43 */
44 i = 0;
45 k = OID__NR;
46 while (i < k) {
47 j = (i + k) / 2;
48
49 xhash = oid_search_table[j].hash;
50 if (xhash > hash) {
51 k = j;
52 continue;
53 }
54 if (xhash < hash) {
55 i = j + 1;
56 continue;
57 }
58
59 oid = oid_search_table[j].oid;
60 len = oid_index[oid + 1] - oid_index[oid];
61 if (len > datasize) {
62 k = j;
63 continue;
64 }
65 if (len < datasize) {
66 i = j + 1;
67 continue;
68 }
69
70 /* Variation is most likely to be at the tail end of the
71 * OID, so do the comparison in reverse.
72 */
73 while (len > 0) {
74 unsigned char a = oid_data[oid_index[oid] + --len];
75 unsigned char b = octets[len];
76 if (a > b) {
77 k = j;
78 goto next;
79 }
80 if (a < b) {
81 i = j + 1;
82 goto next;
83 }
84 }
85 return oid;
86 next:
87 ;
88 }
89
90 return OID__NR;
91}
92EXPORT_SYMBOL_GPL(look_up_OID);
93
94/*
95 * sprint_OID - Print an Object Identifier into a buffer
96 * @data: The encoded OID to print
97 * @datasize: The size of the encoded OID
98 * @buffer: The buffer to render into
99 * @bufsize: The size of the buffer
100 *
101 * The OID is rendered into the buffer in "a.b.c.d" format and the number of
102 * bytes is returned. -EBADMSG is returned if the data could not be intepreted
103 * and -ENOBUFS if the buffer was too small.
104 */
105int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize)
106{
107 const unsigned char *v = data, *end = v + datasize;
108 unsigned long num;
109 unsigned char n;
110 size_t ret;
111 int count;
112
113 if (v >= end)
114 return -EBADMSG;
115
116 n = *v++;
117 ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40);
118 buffer += count;
119 bufsize -= count;
120 if (bufsize == 0)
121 return -ENOBUFS;
122
123 while (v < end) {
124 num = 0;
125 n = *v++;
126 if (!(n & 0x80)) {
127 num = n;
128 } else {
129 num = n & 0x7f;
130 do {
131 if (v >= end)
132 return -EBADMSG;
133 n = *v++;
134 num <<= 7;
135 num |= n & 0x7f;
136 } while (n & 0x80);
137 }
138 ret += count = snprintf(buffer, bufsize, ".%lu", num);
139 buffer += count;
140 bufsize -= count;
141 if (bufsize == 0)
142 return -ENOBUFS;
143 }
144
145 return ret;
146}
147EXPORT_SYMBOL_GPL(sprint_oid);
148
149/**
150 * sprint_OID - Print an Object Identifier into a buffer
151 * @oid: The OID to print
152 * @buffer: The buffer to render into
153 * @bufsize: The size of the buffer
154 *
155 * The OID is rendered into the buffer in "a.b.c.d" format and the number of
156 * bytes is returned.
157 */
158int sprint_OID(enum OID oid, char *buffer, size_t bufsize)
159{
160 int ret;
161
162 BUG_ON(oid >= OID__NR);
163
164 ret = sprint_oid(oid_data + oid_index[oid],
165 oid_index[oid + 1] - oid_index[oid],
166 buffer, bufsize);
167 BUG_ON(ret == -EBADMSG);
168 return ret;
169}
170EXPORT_SYMBOL_GPL(sprint_OID);