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 <linux/asn1.h> |
15 | #include "oid_registry_data.c" |
16 | |
17 | MODULE_DESCRIPTION("OID Registry" ); |
18 | MODULE_AUTHOR("Red Hat, Inc." ); |
19 | MODULE_LICENSE("GPL" ); |
20 | |
21 | /** |
22 | * look_up_OID - Find an OID registration for the specified data |
23 | * @data: Binary representation of the OID |
24 | * @datasize: Size of the binary representation |
25 | */ |
26 | enum OID look_up_OID(const void *data, size_t datasize) |
27 | { |
28 | const unsigned char *octets = data; |
29 | enum OID oid; |
30 | unsigned char xhash; |
31 | unsigned i, j, k, hash; |
32 | size_t len; |
33 | |
34 | /* Hash the OID data */ |
35 | hash = datasize - 1; |
36 | |
37 | for (i = 0; i < datasize; i++) |
38 | hash += octets[i] * 33; |
39 | hash = (hash >> 24) ^ (hash >> 16) ^ (hash >> 8) ^ hash; |
40 | hash &= 0xff; |
41 | |
42 | /* Binary search the OID registry. OIDs are stored in ascending order |
43 | * of hash value then ascending order of size and then in ascending |
44 | * order of reverse value. |
45 | */ |
46 | i = 0; |
47 | k = OID__NR; |
48 | while (i < k) { |
49 | j = (i + k) / 2; |
50 | |
51 | xhash = oid_search_table[j].hash; |
52 | if (xhash > hash) { |
53 | k = j; |
54 | continue; |
55 | } |
56 | if (xhash < hash) { |
57 | i = j + 1; |
58 | continue; |
59 | } |
60 | |
61 | oid = oid_search_table[j].oid; |
62 | len = oid_index[oid + 1] - oid_index[oid]; |
63 | if (len > datasize) { |
64 | k = j; |
65 | continue; |
66 | } |
67 | if (len < datasize) { |
68 | i = j + 1; |
69 | continue; |
70 | } |
71 | |
72 | /* Variation is most likely to be at the tail end of the |
73 | * OID, so do the comparison in reverse. |
74 | */ |
75 | while (len > 0) { |
76 | unsigned char a = oid_data[oid_index[oid] + --len]; |
77 | unsigned char b = octets[len]; |
78 | if (a > b) { |
79 | k = j; |
80 | goto next; |
81 | } |
82 | if (a < b) { |
83 | i = j + 1; |
84 | goto next; |
85 | } |
86 | } |
87 | return oid; |
88 | next: |
89 | ; |
90 | } |
91 | |
92 | return OID__NR; |
93 | } |
94 | EXPORT_SYMBOL_GPL(look_up_OID); |
95 | |
96 | /** |
97 | * parse_OID - Parse an OID from a bytestream |
98 | * @data: Binary representation of the header + OID |
99 | * @datasize: Size of the binary representation |
100 | * @oid: Pointer to oid to return result |
101 | * |
102 | * Parse an OID from a bytestream that holds the OID in the format |
103 | * ASN1_OID | length | oid. The length indicator must equal to datasize - 2. |
104 | * -EBADMSG is returned if the bytestream is too short. |
105 | */ |
106 | int parse_OID(const void *data, size_t datasize, enum OID *oid) |
107 | { |
108 | const unsigned char *v = data; |
109 | |
110 | /* we need 2 bytes of header and at least 1 byte for oid */ |
111 | if (datasize < 3 || v[0] != ASN1_OID || v[1] != datasize - 2) |
112 | return -EBADMSG; |
113 | |
114 | *oid = look_up_OID(data + 2, datasize - 2); |
115 | return 0; |
116 | } |
117 | EXPORT_SYMBOL_GPL(parse_OID); |
118 | |
119 | /* |
120 | * sprint_OID - Print an Object Identifier into a buffer |
121 | * @data: The encoded OID to print |
122 | * @datasize: The size of the encoded OID |
123 | * @buffer: The buffer to render into |
124 | * @bufsize: The size of the buffer |
125 | * |
126 | * The OID is rendered into the buffer in "a.b.c.d" format and the number of |
127 | * bytes is returned. -EBADMSG is returned if the data could not be interpreted |
128 | * and -ENOBUFS if the buffer was too small. |
129 | */ |
130 | int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize) |
131 | { |
132 | const unsigned char *v = data, *end = v + datasize; |
133 | unsigned long num; |
134 | unsigned char n; |
135 | size_t ret; |
136 | int count; |
137 | |
138 | if (v >= end) |
139 | goto bad; |
140 | |
141 | n = *v++; |
142 | ret = count = snprintf(buf: buffer, size: bufsize, fmt: "%u.%u" , n / 40, n % 40); |
143 | if (count >= bufsize) |
144 | return -ENOBUFS; |
145 | buffer += count; |
146 | bufsize -= count; |
147 | |
148 | while (v < end) { |
149 | n = *v++; |
150 | if (!(n & 0x80)) { |
151 | num = n; |
152 | } else { |
153 | num = n & 0x7f; |
154 | do { |
155 | if (v >= end) |
156 | goto bad; |
157 | n = *v++; |
158 | num <<= 7; |
159 | num |= n & 0x7f; |
160 | } while (n & 0x80); |
161 | } |
162 | ret += count = snprintf(buf: buffer, size: bufsize, fmt: ".%lu" , num); |
163 | if (count >= bufsize) |
164 | return -ENOBUFS; |
165 | buffer += count; |
166 | bufsize -= count; |
167 | } |
168 | |
169 | return ret; |
170 | |
171 | bad: |
172 | snprintf(buf: buffer, size: bufsize, fmt: "(bad)" ); |
173 | return -EBADMSG; |
174 | } |
175 | EXPORT_SYMBOL_GPL(sprint_oid); |
176 | |
177 | /** |
178 | * sprint_OID - Print an Object Identifier into a buffer |
179 | * @oid: The OID to print |
180 | * @buffer: The buffer to render into |
181 | * @bufsize: The size of the buffer |
182 | * |
183 | * The OID is rendered into the buffer in "a.b.c.d" format and the number of |
184 | * bytes is returned. |
185 | */ |
186 | int sprint_OID(enum OID oid, char *buffer, size_t bufsize) |
187 | { |
188 | int ret; |
189 | |
190 | BUG_ON(oid >= OID__NR); |
191 | |
192 | ret = sprint_oid(oid_data + oid_index[oid], |
193 | oid_index[oid + 1] - oid_index[oid], |
194 | buffer, bufsize); |
195 | BUG_ON(ret == -EBADMSG); |
196 | return ret; |
197 | } |
198 | EXPORT_SYMBOL_GPL(sprint_OID); |
199 | |