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(buffer, bufsize, "%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 num = 0; 150 n = *v++; 151 if (!(n & 0x80)) { 152 num = n; 153 } else { 154 num = n & 0x7f; 155 do { 156 if (v >= end) 157 goto bad; 158 n = *v++; 159 num <<= 7; 160 num |= n & 0x7f; 161 } while (n & 0x80); 162 } 163 ret += count = snprintf(buffer, bufsize, ".%lu", num); 164 if (count >= bufsize) 165 return -ENOBUFS; 166 buffer += count; 167 bufsize -= count; 168 } 169 170 return ret; 171 172 bad: 173 snprintf(buffer, bufsize, "(bad)"); 174 return -EBADMSG; 175 } 176 EXPORT_SYMBOL_GPL(sprint_oid); 177 178 /** 179 * sprint_OID - Print an Object Identifier into a buffer 180 * @oid: The OID to print 181 * @buffer: The buffer to render into 182 * @bufsize: The size of the buffer 183 * 184 * The OID is rendered into the buffer in "a.b.c.d" format and the number of 185 * bytes is returned. 186 */ 187 int sprint_OID(enum OID oid, char *buffer, size_t bufsize) 188 { 189 int ret; 190 191 BUG_ON(oid >= OID__NR); 192 193 ret = sprint_oid(oid_data + oid_index[oid], 194 oid_index[oid + 1] - oid_index[oid], 195 buffer, bufsize); 196 BUG_ON(ret == -EBADMSG); 197 return ret; 198 } 199 EXPORT_SYMBOL_GPL(sprint_OID); 200