/* * Copyright (c) 2005-2010 Apple Inc. All Rights Reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* * DER_Decode.h - DER decoding routines */ #ifndef _DER_DECODE_H_ #define _DER_DECODE_H_ #ifdef __cplusplus extern "C" { #endif #include "libDER.h" #include <stdbool.h> /* * Decoding one item consists of extracting its tag, a pointer * to the actual content, and the length of the content. Those * three are represented by a DERDecodedInfo. */ typedef struct { DERTag tag; DERItem content; } DERDecodedInfo; /* * Basic decoding primitive. Only works with: * * -- definite length encoding * -- one-byte tags * -- max content length fits in a DERSize * * No malloc or copy of the contents is performed; the returned * content->content.data is a pointer into the incoming der data. */ DERReturn DERDecodeItem( const DERItem *der, /* data to decode */ DERDecodedInfo *decoded); /* RETURNED */ /* * Given a BIT_STRING, in the form of its raw content bytes, * obtain the number of unused bits and the raw bit string bytes. */ DERReturn DERParseBitString( const DERItem *contents, DERItem *bitStringBytes, /* RETURNED */ DERByte *numUnusedBits); /* RETURNED */ /* * Given a BOOLEAN, in the form of its raw content bytes, * obtain it's value. */ DERReturn DERParseBoolean( const DERItem *contents, bool defaultValue, bool *value); /* RETURNED */ DERReturn DERParseInteger( const DERItem *contents, uint32_t *value); /* RETURNED */ /* * Sequence/set decode support. */ /* state representing a sequence or set being decoded */ typedef struct { DERByte *nextItem; DERByte *end; } DERSequence; /* * To decode a set or sequence, call DERDecodeSeqInit or * DERDecodeSeqContentInit once, then call DERDecodeSeqNext to * get each enclosed item. * * DERDecodeSeqNext returns DR_EndOfSequence when no more * items are available. */ /* * Use this to parse the top level sequence's tag and content length. */ DERReturn DERDecodeSeqInit( const DERItem *der, /* data to decode */ DERTag *tag, /* RETURNED tag of sequence/set. This will be * either ASN1_CONSTR_SEQUENCE or * ASN1_CONSTR_SET. */ DERSequence *derSeq); /* RETURNED, to use in DERDecodeSeqNext */ /* * Use this to start in on decoding a sequence's content, when * the top-level tag and content have already been decoded. */ DERReturn DERDecodeSeqContentInit( const DERItem *content, DERSequence *derSeq); /* RETURNED, to use in DERDecodeSeqNext */ /* obtain the next decoded item in a sequence or set */ DERReturn DERDecodeSeqNext( DERSequence *derSeq, DERDecodedInfo *decoded); /* RETURNED */ /* * High level sequence decode. */ /* * Per-item decode options. */ /* Explicit default, no options */ #define DER_DEC_NO_OPTS 0x0000 /* This item optional, can be skipped during decode */ #define DER_DEC_OPTIONAL 0x0001 /* Skip the tag check; accept anything. */ #define DER_DEC_ASN_ANY 0x0002 /* Skip item, no write to DERDecodedInfo (but tag check still performed) */ #define DER_DEC_SKIP 0x0004 /* Save full DER encoding in DERDecodedInfo, including tag and length. Normally * only the content is saved. */ #define DER_DEC_SAVE_DER 0x0008 /* * High level sequence parse, starting with top-level tag and content. * Top level tag must be ASN1_CONSTR_SEQUENCE - if it's not, and that's * OK, use DERParseSequenceContent(). * * These never return DR_EndOfSequence - if an *unexpected* end of sequence * occurs, return DR_IncompleteSeq. * * Results of the decoding of one item are placed in a DERItem whose address * is the dest arg plus the offset value in the associated DERItemSpec. * * Items which are optional (DER_DEC_OPTIONAL) and which are not found, * leave their associated DERDecodedInfos unmodified. * * Processing of a sequence ends on detection of any error or after the * last DERItemSpec is processed. * * The sizeToZero argument, if nonzero, indicates the number of bytes * starting at dest to zero before processing the sequence. This is * generally desirable, particularly if there are any DER_DEC_OPTIONAL * items in the sequence; skipped optional items are detected by the * caller via a NULL DERDecodedInfo.content.data; if this hasn't been * explicitly zeroed (generally, by passing a nonzero value of sizeToZero), * skipped items can't be detected. */ DERReturn DERParseSequence( const DERItem *der, DERShort numItems, /* size of itemSpecs[] */ const DERItemSpec *itemSpecs, void *dest, /* DERDecodedInfo(s) here RETURNED */ DERSize sizeToZero); /* optional */ /* high level sequence parse, starting with sequence's content */ DERReturn DERParseSequenceContent( const DERItem *content, DERShort numItems, /* size of itemSpecs[] */ const DERItemSpec *itemSpecs, void *dest, /* DERDecodedInfo(s) here RETURNED */ DERSize sizeToZero); /* optional */ #ifdef __cplusplus } #endif #endif /* _DER_DECODE_H_ */