Check client topic inputs for valid UTF-8.
Roger A. Light
9 years ago
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/*
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Copyright (c) 2016 Roger Light <roger@atchoo.org>
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All rights reserved. This program and the accompanying materials
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are made available under the terms of the Eclipse Public License v1.0
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and Eclipse Distribution License v1.0 which accompany this distribution.
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The Eclipse Public License is available at
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http://www.eclipse.org/legal/epl-v10.html
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and the Eclipse Distribution License is available at
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http://www.eclipse.org/org/documents/edl-v10.php.
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Contributors:
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Roger Light - initial implementation.
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*/
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#include <stdio.h>
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#include "mosquitto.h"
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int mosquitto_validate_utf8(const char *str, int len)
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{
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int i;
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int j;
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int codelen;
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int codepoint;
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const unsigned char *ustr = (const unsigned char *)str;
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if(!str) return MOSQ_ERR_INVAL;
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if(len < 1 || len > 65536) return MOSQ_ERR_INVAL;
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for(i=0; i<len; i++){
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if(ustr[i] == 0){
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return MOSQ_ERR_MALFORMED_UTF8;
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}else if(ustr[i] <= 0x7f){
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codelen = 1;
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codepoint = ustr[i];
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}else if((ustr[i] & 0xE0) == 0xC0){
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/* 110xxxxx - 2 byte sequence */
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if(ustr[i] == 0xC0 || ustr[i] == 0xC1){
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/* Invalid bytes */
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return MOSQ_ERR_MALFORMED_UTF8;
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}
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codelen = 2;
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codepoint = (ustr[i] & 0x1F);
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}else if((ustr[i] & 0xF0) == 0xE0){
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// 1110xxxx - 3 byte sequence
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codelen = 3;
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codepoint = (ustr[i] & 0x0F);
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}else if((ustr[i] & 0xF8) == 0xF0){
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// 11110xxx - 4 byte sequence
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if(ustr[i] > 0xF4){
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/* Invalid, this would produce values > 0x10FFFF. */
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return MOSQ_ERR_MALFORMED_UTF8;
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}
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codelen = 4;
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codepoint = (ustr[i] & 0x07);
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}else{
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/* Unexpected continuation byte. */
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return MOSQ_ERR_MALFORMED_UTF8;
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}
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/* Reconstruct full code point */
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for(j=0; j<codelen-1; j++){
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if(i == len-1){
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/* Not enough data */
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return MOSQ_ERR_MALFORMED_UTF8;
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}
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if((ustr[++i] & 0xC0) != 0x80){
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/* Not a continuation byte */
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return MOSQ_ERR_MALFORMED_UTF8;
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}
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codepoint = (codepoint<<6) | (ustr[i] & 0x3F);
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}
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/* Check for UTF-16 high/low surrogates */
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if(codepoint >= 0xD800 && codepoint <= 0xDFFF){
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return MOSQ_ERR_MALFORMED_UTF8;
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}
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/* Check for overlong encodings */
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if(codelen == 2 && codepoint < 0x0080){
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return MOSQ_ERR_MALFORMED_UTF8;
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}else if(codelen == 3 && codepoint < 0x0800){
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return MOSQ_ERR_MALFORMED_UTF8;
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}else if(codelen == 4 && codepoint < 0x10000){
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return MOSQ_ERR_MALFORMED_UTF8;
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}
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}
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return MOSQ_ERR_SUCCESS;
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}
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