1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* ASN.1 Object identifier (OID) registry
3 *
4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #include <linux/module.h>
9 #include <linux/export.h>
10 #include <linux/oid_registry.h>
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/bug.h>
14 #include "oid_registry_data.c"
15
16 MODULE_DESCRIPTION("OID Registry");
17 MODULE_AUTHOR("Red Hat, Inc.");
18 MODULE_LICENSE("GPL");
19
20 /**
21 * look_up_OID - Find an OID registration for the specified data
22 * @data: Binary representation of the OID
23 * @datasize: Size of the binary representation
24 */
25 enum OID look_up_OID(const void *data, size_t datasize)
26 {
27 const unsigned char *octets = data;
28 enum OID oid;
29 unsigned char xhash;
30 unsigned i, j, k, hash;
31 size_t len;
32
33 /* Hash the OID data */
34 hash = datasize - 1;
35
36 for (i = 0; i < datasize; i++)
37 hash += octets[i] * 33;
38 hash = (hash >> 24) ^ (hash >> 16) ^ (hash >> 8) ^ hash;
39 hash &= 0xff;
40
41 /* Binary search the OID registry. OIDs are stored in ascending order
42 * of hash value then ascending order of size and then in ascending
43 * order of reverse value.
44 */
45 i = 0;
46 k = OID__NR;
47 while (i < k) {
48 j = (i + k) / 2;
49
50 xhash = oid_search_table[j].hash;
51 if (xhash > hash) {
52 k = j;
53 continue;
54 }
55 if (xhash < hash) {
56 i = j + 1;
57 continue;
58 }
59
60 oid = oid_search_table[j].oid;
61 len = oid_index[oid + 1] - oid_index[oid];
62 if (len > datasize) {
63 k = j;
64 continue;
65 }
66 if (len < datasize) {
67 i = j + 1;
68 continue;
69 }
70
71 /* Variation is most likely to be at the tail end of the
72 * OID, so do the comparison in reverse.
73 */
74 while (len > 0) {
75 unsigned char a = oid_data[oid_index[oid] + --len];
76 unsigned char b = octets[len];
77 if (a > b) {
78 k = j;
79 goto next;
80 }
81 if (a < b) {
82 i = j + 1;
83 goto next;
84 }
85 }
86 return oid;
87 next:
88 ;
89 }
90
91 return OID__NR;
92 }
93 EXPORT_SYMBOL_GPL(look_up_OID);
94
95 /*
96 * sprint_OID - Print an Object Identifier into a buffer
97 * @data: The encoded OID to print
98 * @datasize: The size of the encoded OID
99 * @buffer: The buffer to render into
100 * @bufsize: The size of the buffer
101 *
102 * The OID is rendered into the buffer in "a.b.c.d" format and the number of
103 * bytes is returned. -EBADMSG is returned if the data could not be intepreted
104 * and -ENOBUFS if the buffer was too small.
105 */
106 int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize)
107 {
108 const unsigned char *v = data, *end = v + datasize;
109 unsigned long num;
110 unsigned char n;
111 size_t ret;
112 int count;
113
114 if (v >= end)
115 goto bad;
116
117 n = *v++;
118 ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40);
119 if (count >= bufsize)
120 return -ENOBUFS;
121 buffer += count;
122 bufsize -= count;
123
124 while (v < end) {
125 num = 0;
126 n = *v++;
127 if (!(n & 0x80)) {
128 num = n;
129 } else {
130 num = n & 0x7f;
131 do {
132 if (v >= end)
133 goto bad;
134 n = *v++;
135 num <<= 7;
136 num |= n & 0x7f;
137 } while (n & 0x80);
138 }
139 ret += count = snprintf(buffer, bufsize, ".%lu", num);
140 if (count >= bufsize)
141 return -ENOBUFS;
142 buffer += count;
143 bufsize -= count;
144 }
145
146 return ret;
147
148 bad:
149 snprintf(buffer, bufsize, "(bad)");
150 return -EBADMSG;
151 }
152 EXPORT_SYMBOL_GPL(sprint_oid);
153
154 /**
155 * sprint_OID - Print an Object Identifier into a buffer
156 * @oid: The OID to print
157 * @buffer: The buffer to render into
158 * @bufsize: The size of the buffer
159 *
160 * The OID is rendered into the buffer in "a.b.c.d" format and the number of
161 * bytes is returned.
162 */
163 int sprint_OID(enum OID oid, char *buffer, size_t bufsize)
164 {
165 int ret;
166
167 BUG_ON(oid >= OID__NR);
168
169 ret = sprint_oid(oid_data + oid_index[oid],
170 oid_index[oid + 1] - oid_index[oid],
171 buffer, bufsize);
172 BUG_ON(ret == -EBADMSG);
173 return ret;
174 }
175 EXPORT_SYMBOL_GPL(sprint_OID);