58 lines
1.2 KiB
C
58 lines
1.2 KiB
C
/*
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* Basic ASN1 parser functions
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*
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* Copyright 2009,2010 by Karsten Keil <kkeil@linux-pingi.de>
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*
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* This code is free software; you can redistribute it and/or modify
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* it under the terms of the GNU LESSER GENERAL PUBLIC LICENSE
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* version 2.1 as published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU LESSER GENERAL PUBLIC LICENSE for more details.
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*
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*/
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#include "asn1.h"
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int ParseTag(u_char * p, u_char * end, int *tag)
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{
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if (p >= end) {
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eprint("ParseTag underflow %p/%p\n", p, end);
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return -1;
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}
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*tag = *p;
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return 1;
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}
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int ParseLen(u_char * p, u_char * end, int *len)
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{
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int l, i;
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if (p >= end) {
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eprint("ParseLen underflow %p/%p\n", p, end);
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return -1;
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}
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if (*p == 0x80) { // indefinite
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*len = -1;
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return 1;
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}
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if (!(*p & 0x80)) { // one byte
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*len = *p;
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return 1;
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}
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*len = 0;
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l = *p & ~0x80;
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p++;
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if (p + l >= end) {
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eprint("ParseLen underflow %p/%p\n", p, end);
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return -1;
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}
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for (i = 0; i < l; i++) {
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*len = (*len << 8) + *p;
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p++;
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}
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return l + 1;
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}
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