iBoot/lib/pki/libDER/DER_Decode.h

220 lines
6.8 KiB
C

/*
* 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_
#include <libDER/libDER.h>
#include <stdbool.h>
__BEGIN_DECLS
/*
* 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 */
/*
* Basic decoding primitive. Allows for decoding with a partial buffer.
* if allowPartialBuffer is true. A partial buffer would normally fail
* because the encoded length would be greater than the size of the buffer passed in.
* Only works with:
*
* -- definite length encoding
* -- one-byte tags (unless DER_MULTIBYTE_TAGS is defined)
* -- 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 DERDecodeItemPartialBuffer(
const DERItem *der, /* data to decode */
DERDecodedInfo *decoded, /* RETURNED */
bool allowPartialBuffer);
/*
* 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 *value); /* RETURNED */
DERReturn DERParseBooleanWithDefault(
const DERItem *contents,
bool defaultValue,
bool *value); /* RETURNED */
/*
* Given a positive INTEGER, in the form of its raw content bytes,
* obtain it's value as a 32 bit or 64 bit quantity.
* Returns DR_BufOverflow if the value is too large to fit in the return type
*/
DERReturn DERParseInteger(
const DERItem *contents,
uint32_t *value); /* RETURNED */
DERReturn DERParseInteger64(
const DERItem *contents,
uint64_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 */
__END_DECLS
#endif /* _DER_DECODE_H_ */