// SPDX-License-Identifier: GPL-2.0-or-later/* ASN.1 Object identifier (OID) registry * * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #include <linux/module.h>#include <linux/export.h>#include <linux/oid_registry.h>#include <linux/kernel.h>#include <linux/errno.h>#include <linux/bug.h>#include <linux/asn1.h>#include "oid_registry_data.c" MODULE_DESCRIPTION("OID Registry");MODULE_AUTHOR("Red Hat, Inc.");MODULE_LICENSE("GPL"); /** * look_up_OID - Find an OID registration for the specified data * @data: Binary representation of the OID * @datasize: Size of the binary representation */enum OID look_up_OID(const void *data, size_t datasize){	const unsigned char *octets = data;	enum OID oid;	unsigned char xhash;	unsigned i, j, k, hash;	size_t len; 	/* Hash the OID data */	hash = datasize - 1; 	for (i = 0; i < datasize; i++)		hash += octets[i] * 33;	hash = (hash >> 24) ^ (hash >> 16) ^ (hash >> 8) ^ hash;	hash &= 0xff; 	/* Binary search the OID registry.  OIDs are stored in ascending order	 * of hash value then ascending order of size and then in ascending	 * order of reverse value.	 */	i = 0;	k = OID__NR;	while (i < k) {		j = (i + k) / 2; 		xhash = oid_search_table[j].hash;		if (xhash > hash) {			k = j;			continue;		}		if (xhash < hash) {			i = j + 1;			continue;		} 		oid = oid_search_table[j].oid;		len = oid_index[oid + 1] - oid_index[oid];		if (len > datasize) {			k = j;			continue;		}		if (len < datasize) {			i = j + 1;			continue;		} 		/* Variation is most likely to be at the tail end of the		 * OID, so do the comparison in reverse.		 */		while (len > 0) {			unsigned char a = oid_data[oid_index[oid] + --len];			unsigned char b = octets[len];			if (a > b) {				k = j;				goto next;			}			if (a < b) {				i = j + 1;				goto next;			}		}		return oid;	next:		;	} 	return OID__NR;}EXPORT_SYMBOL_GPL(look_up_OID); /** * parse_OID - Parse an OID from a bytestream * @data: Binary representation of the header + OID * @datasize: Size of the binary representation * @oid: Pointer to oid to return result * * Parse an OID from a bytestream that holds the OID in the format * ASN1_OID | length | oid. The length indicator must equal to datasize - 2. * -EBADMSG is returned if the bytestream is too short. */int parse_OID(const void *data, size_t datasize, enum OID *oid){	const unsigned char *v = data; 	/* we need 2 bytes of header and at least 1 byte for oid */	if (datasize < 3 || v[0] != ASN1_OID || v[1] != datasize - 2)		return -EBADMSG; 	*oid = look_up_OID(data + 2, datasize - 2);	return 0;}EXPORT_SYMBOL_GPL(parse_OID); /* * sprint_oid - Print an Object Identifier into a buffer * @data: The encoded OID to print * @datasize: The size of the encoded OID * @buffer: The buffer to render into * @bufsize: The size of the buffer * * The OID is rendered into the buffer in "a.b.c.d" format and the number of * bytes is returned.  -EBADMSG is returned if the data could not be interpreted * and -ENOBUFS if the buffer was too small. */int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize){	const unsigned char *v = data, *end = v + datasize;	unsigned long num;	unsigned char n;	size_t ret;	int count; 	if (v >= end)		goto bad; 	n = *v++;	ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40);	if (count >= bufsize)		return -ENOBUFS;	buffer += count;	bufsize -= count; 	while (v < end) {		n = *v++;		if (!(n & 0x80)) {			num = n;		} else {			num = n & 0x7f;			do {				if (v >= end)					goto bad;				n = *v++;				num <<= 7;				num |= n & 0x7f;			} while (n & 0x80);		}		ret += count = snprintf(buffer, bufsize, ".%lu", num);		if (count >= bufsize)			return -ENOBUFS;		buffer += count;		bufsize -= count;	} 	return ret; bad:	snprintf(buffer, bufsize, "(bad)");	return -EBADMSG;}EXPORT_SYMBOL_GPL(sprint_oid);