blob: 150e04d70303092ee6193d43ca4487012afb6576
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/module.h> |
13 | #include <linux/export.h> |
14 | #include <linux/oid_registry.h> |
15 | #include <linux/kernel.h> |
16 | #include <linux/errno.h> |
17 | #include <linux/bug.h> |
18 | #include "oid_registry_data.c" |
19 | |
20 | MODULE_DESCRIPTION("OID Registry"); |
21 | MODULE_AUTHOR("Red Hat, Inc."); |
22 | MODULE_LICENSE("GPL"); |
23 | |
24 | /** |
25 | * look_up_OID - Find an OID registration for the specified data |
26 | * @data: Binary representation of the OID |
27 | * @datasize: Size of the binary representation |
28 | */ |
29 | enum OID look_up_OID(const void *data, size_t datasize) |
30 | { |
31 | const unsigned char *octets = data; |
32 | enum OID oid; |
33 | unsigned char xhash; |
34 | unsigned i, j, k, hash; |
35 | size_t len; |
36 | |
37 | /* Hash the OID data */ |
38 | hash = datasize - 1; |
39 | |
40 | for (i = 0; i < datasize; i++) |
41 | hash += octets[i] * 33; |
42 | hash = (hash >> 24) ^ (hash >> 16) ^ (hash >> 8) ^ hash; |
43 | hash &= 0xff; |
44 | |
45 | /* Binary search the OID registry. OIDs are stored in ascending order |
46 | * of hash value then ascending order of size and then in ascending |
47 | * order of reverse value. |
48 | */ |
49 | i = 0; |
50 | k = OID__NR; |
51 | while (i < k) { |
52 | j = (i + k) / 2; |
53 | |
54 | xhash = oid_search_table[j].hash; |
55 | if (xhash > hash) { |
56 | k = j; |
57 | continue; |
58 | } |
59 | if (xhash < hash) { |
60 | i = j + 1; |
61 | continue; |
62 | } |
63 | |
64 | oid = oid_search_table[j].oid; |
65 | len = oid_index[oid + 1] - oid_index[oid]; |
66 | if (len > datasize) { |
67 | k = j; |
68 | continue; |
69 | } |
70 | if (len < datasize) { |
71 | i = j + 1; |
72 | continue; |
73 | } |
74 | |
75 | /* Variation is most likely to be at the tail end of the |
76 | * OID, so do the comparison in reverse. |
77 | */ |
78 | while (len > 0) { |
79 | unsigned char a = oid_data[oid_index[oid] + --len]; |
80 | unsigned char b = octets[len]; |
81 | if (a > b) { |
82 | k = j; |
83 | goto next; |
84 | } |
85 | if (a < b) { |
86 | i = j + 1; |
87 | goto next; |
88 | } |
89 | } |
90 | return oid; |
91 | next: |
92 | ; |
93 | } |
94 | |
95 | return OID__NR; |
96 | } |
97 | EXPORT_SYMBOL_GPL(look_up_OID); |
98 | |
99 | /* |
100 | * sprint_OID - Print an Object Identifier into a buffer |
101 | * @data: The encoded OID to print |
102 | * @datasize: The size of the encoded OID |
103 | * @buffer: The buffer to render into |
104 | * @bufsize: The size of the buffer |
105 | * |
106 | * The OID is rendered into the buffer in "a.b.c.d" format and the number of |
107 | * bytes is returned. -EBADMSG is returned if the data could not be intepreted |
108 | * and -ENOBUFS if the buffer was too small. |
109 | */ |
110 | int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize) |
111 | { |
112 | const unsigned char *v = data, *end = v + datasize; |
113 | unsigned long num; |
114 | unsigned char n; |
115 | size_t ret; |
116 | int count; |
117 | |
118 | if (v >= end) |
119 | goto bad; |
120 | |
121 | n = *v++; |
122 | ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40); |
123 | buffer += count; |
124 | bufsize -= count; |
125 | if (bufsize == 0) |
126 | return -ENOBUFS; |
127 | |
128 | while (v < end) { |
129 | num = 0; |
130 | n = *v++; |
131 | if (!(n & 0x80)) { |
132 | num = n; |
133 | } else { |
134 | num = n & 0x7f; |
135 | do { |
136 | if (v >= end) |
137 | goto bad; |
138 | n = *v++; |
139 | num <<= 7; |
140 | num |= n & 0x7f; |
141 | } while (n & 0x80); |
142 | } |
143 | ret += count = snprintf(buffer, bufsize, ".%lu", num); |
144 | buffer += count; |
145 | bufsize -= count; |
146 | if (bufsize == 0) |
147 | return -ENOBUFS; |
148 | } |
149 | |
150 | return ret; |
151 | |
152 | bad: |
153 | snprintf(buffer, bufsize, "(bad)"); |
154 | return -EBADMSG; |
155 | } |
156 | EXPORT_SYMBOL_GPL(sprint_oid); |
157 | |
158 | /** |
159 | * sprint_OID - Print an Object Identifier into a buffer |
160 | * @oid: The OID to print |
161 | * @buffer: The buffer to render into |
162 | * @bufsize: The size of the buffer |
163 | * |
164 | * The OID is rendered into the buffer in "a.b.c.d" format and the number of |
165 | * bytes is returned. |
166 | */ |
167 | int sprint_OID(enum OID oid, char *buffer, size_t bufsize) |
168 | { |
169 | int ret; |
170 | |
171 | BUG_ON(oid >= OID__NR); |
172 | |
173 | ret = sprint_oid(oid_data + oid_index[oid], |
174 | oid_index[oid + 1] - oid_index[oid], |
175 | buffer, bufsize); |
176 | BUG_ON(ret == -EBADMSG); |
177 | return ret; |
178 | } |
179 | EXPORT_SYMBOL_GPL(sprint_OID); |
180 |