encode.c

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/*
 * Copyright 2005 Juan Lang
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * This file implements ASN.1 DER encoding and decoding of a limited set of
 * types.  It isn't a full ASN.1 implementation.  Microsoft implements BER
 * encoding of many of the basic types in msasn1.dll, but that interface is
 * undocumented, so I implement them here.
 *
 * References:
 * "A Layman's Guide to a Subset of ASN.1, BER, and DER", by Burton Kaliski
 * (available online, look for a PDF copy as the HTML versions tend to have
 * translation errors.)
 *
 * RFC3280, http://www.faqs.org/rfcs/rfc3280.html
 *
 * MSDN, especially:
 * http://msdn.microsoft.com/library/en-us/seccrypto/security/constants_for_cryptencodeobject_and_cryptdecodeobject.asp
 */

#include "config.h"
#include "wine/port.h"

#include <assert.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>

#define NONAMELESSUNION

#include "windef.h"
#include "winbase.h"
#include "excpt.h"
#include "wincrypt.h"
#include "winreg.h"
#include "snmp.h"
#include "wine/debug.h"
#include "wine/exception.h"
#include "crypt32_private.h"

/* This is a bit arbitrary, but to set some limit: */
#define MAX_ENCODED_LEN 0x02000000

/* a few asn.1 tags we need */
#define ASN_BOOL            (ASN_UNIVERSAL | ASN_PRIMITIVE | 0x01)
#define ASN_BITSTRING       (ASN_UNIVERSAL | ASN_PRIMITIVE | 0x03)
#define ASN_ENUMERATED      (ASN_UNIVERSAL | ASN_PRIMITIVE | 0x0a)
#define ASN_SETOF           (ASN_UNIVERSAL | ASN_PRIMITIVE | 0x11)
#define ASN_NUMERICSTRING   (ASN_UNIVERSAL | ASN_PRIMITIVE | 0x12)
#define ASN_PRINTABLESTRING (ASN_UNIVERSAL | ASN_PRIMITIVE | 0x13)
#define ASN_IA5STRING       (ASN_UNIVERSAL | ASN_PRIMITIVE | 0x16)
#define ASN_UTCTIME         (ASN_UNIVERSAL | ASN_PRIMITIVE | 0x17)
#define ASN_GENERALTIME     (ASN_UNIVERSAL | ASN_PRIMITIVE | 0x18)

#define ASN_FLAGS_MASK 0xe0
#define ASN_TYPE_MASK  0x1f

WINE_DEFAULT_DEBUG_CHANNEL(crypt);

struct GenericArray
{
    DWORD cItems;
    BYTE *rgItems;
};

typedef BOOL (WINAPI *CryptEncodeObjectFunc)(DWORD, LPCSTR, const void *,
 BYTE *, DWORD *);
typedef BOOL (WINAPI *CryptEncodeObjectExFunc)(DWORD, LPCSTR, const void *,
 DWORD, PCRYPT_ENCODE_PARA, BYTE *, DWORD *);
typedef BOOL (WINAPI *CryptDecodeObjectFunc)(DWORD, LPCSTR, const BYTE *,
 DWORD, DWORD, void *, DWORD *);
typedef BOOL (WINAPI *CryptDecodeObjectExFunc)(DWORD, LPCSTR, const BYTE *,
 DWORD, DWORD, PCRYPT_DECODE_PARA, void *, DWORD *);

/* Prototypes for built-in encoders/decoders.  They follow the Ex style
 * prototypes.  The dwCertEncodingType and lpszStructType are ignored by the
 * built-in functions, but the parameters are retained to simplify
 * CryptEncodeObjectEx/CryptDecodeObjectEx, since they must call functions in
 * external DLLs that follow these signatures.
 */
static BOOL WINAPI CRYPT_AsnEncodeOid(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeExtensions(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeSequenceOfAny(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeBool(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodePubKeyInfo(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeOctets(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeBits(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeBitsSwapBytes(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeInt(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeInteger(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeUnsignedInteger(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);
static BOOL WINAPI CRYPT_AsnEncodeChoiceOfTime(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded);

static BOOL WINAPI CRYPT_AsnDecodeChoiceOfTime(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
static BOOL WINAPI CRYPT_AsnDecodePubKeyInfoInternal(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
/* Like CRYPT_AsnDecodeExtensions, except assumes rgExtension is set ahead of
 * time, doesn't do memory allocation, and doesn't do exception handling.
 * (This isn't intended to be the externally-called one.)
 */
static BOOL WINAPI CRYPT_AsnDecodeExtensionsInternal(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
static BOOL WINAPI CRYPT_AsnDecodeOid(const BYTE *pbEncoded, DWORD cbEncoded,
 DWORD dwFlags, LPSTR pszObjId, DWORD *pcbObjId);
/* Assumes algo->Parameters.pbData is set ahead of time.  Internal func. */
static BOOL WINAPI CRYPT_AsnDecodeAlgorithmId(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
/* Internal function */
static BOOL WINAPI CRYPT_AsnDecodeBool(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
/* Assumes the CRYPT_DATA_BLOB's pbData member has been initialized */
static BOOL WINAPI CRYPT_AsnDecodeOctetsInternal(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
/* Like CRYPT_AsnDecodeBits, but assumes the CRYPT_INTEGER_BLOB's pbData
 * member has been initialized, doesn't do exception handling, and doesn't do
 * memory allocation.
 */
static BOOL WINAPI CRYPT_AsnDecodeBitsInternal(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
static BOOL WINAPI CRYPT_AsnDecodeBits(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
static BOOL WINAPI CRYPT_AsnDecodeInt(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
/* Like CRYPT_AsnDecodeInteger, but assumes the CRYPT_INTEGER_BLOB's pbData
 * member has been initialized, doesn't do exception handling, and doesn't do
 * memory allocation.
 */
static BOOL WINAPI CRYPT_AsnDecodeIntegerInternal(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const BYTE *pbEncoded, DWORD cbEncoded, DWORD dwFlags,
 PCRYPT_DECODE_PARA pDecodePara, void *pvStructInfo, DWORD *pcbStructInfo);
/* Like CRYPT_AsnDecodeInteger, but unsigned.  */
static BOOL WINAPI CRYPT_AsnDecodeUnsignedIntegerInternal(
 DWORD dwCertEncodingType, LPCSTR lpszStructType, const BYTE *pbEncoded,
 DWORD cbEncoded, DWORD dwFlags, PCRYPT_DECODE_PARA pDecodePara,
 void *pvStructInfo, DWORD *pcbStructInfo);

BOOL WINAPI CryptEncodeObject(DWORD dwCertEncodingType, LPCSTR lpszStructType,
 const void *pvStructInfo, BYTE *pbEncoded, DWORD *pcbEncoded)
{
    static HCRYPTOIDFUNCSET set = NULL;
    BOOL ret = FALSE;
    HCRYPTOIDFUNCADDR hFunc;
    CryptEncodeObjectFunc pCryptEncodeObject;

    TRACE("(0x%08lx, %s, %p, %p, %p)\n", dwCertEncodingType,
     debugstr_a(lpszStructType), pvStructInfo, pbEncoded,
     pcbEncoded);

    if (!pbEncoded && !pcbEncoded)
    {
        SetLastError(ERROR_INVALID_PARAMETER);
        return FALSE;
    }

    /* Try registered DLL first.. */
    if (!set)
        set = CryptInitOIDFunctionSet(CRYPT_OID_ENCODE_OBJECT_FUNC, 0);
    CryptGetOIDFunctionAddress(set, dwCertEncodingType, lpszStructType, 0,
     (void **)&pCryptEncodeObject, &hFunc);
    if (pCryptEncodeObject)
    {
        ret = pCryptEncodeObject(dwCertEncodingType, lpszStructType,
         pvStructInfo, pbEncoded, pcbEncoded);
        CryptFreeOIDFunctionAddress(hFunc, 0);
    }
    else
    {
        /* If not, use CryptEncodeObjectEx */
        ret = CryptEncodeObjectEx(dwCertEncodingType, lpszStructType,
         pvStructInfo, 0, NULL, pbEncoded, pcbEncoded);
    }
    return ret;
}

/* Helper function to check *pcbEncoded, set it to the required size, and
 * optionally to allocate memory.  Assumes pbEncoded is not NULL.
 * If CRYPT_ENCODE_ALLOC_FLAG is set in dwFlags, *pbEncoded will be set to a
 * pointer to the newly allocated memory.
 */
static BOOL CRYPT_EncodeEnsureSpace(DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded,
 DWORD bytesNeeded)
{
    BOOL ret = TRUE;

    if (dwFlags & CRYPT_ENCODE_ALLOC_FLAG)
    {
        if (pEncodePara && pEncodePara->pfnAlloc)
            *(BYTE **)pbEncoded = pEncodePara->pfnAlloc(bytesNeeded);
        else
            *(BYTE **)pbEncoded = LocalAlloc(0, bytesNeeded);
        if (!*(BYTE **)pbEncoded)
            ret = FALSE;
        else
            *pcbEncoded = bytesNeeded;
    }
    else if (bytesNeeded > *pcbEncoded)
    {
        *pcbEncoded = bytesNeeded;
        SetLastError(ERROR_MORE_DATA);
        ret = FALSE;
    }
    return ret;
}

static BOOL CRYPT_EncodeLen(DWORD len, BYTE *pbEncoded, DWORD *pcbEncoded)
{
    DWORD bytesNeeded, significantBytes = 0;

    if (len <= 0x7f)
        bytesNeeded = 1;
    else
    {
        DWORD temp;

        for (temp = len, significantBytes = sizeof(temp); !(temp & 0xff000000);
         temp <<= 8, significantBytes--)
            ;
        bytesNeeded = significantBytes + 1;
    }
    if (!pbEncoded)
    {
        *pcbEncoded = bytesNeeded;
        return TRUE;
    }
    if (*pcbEncoded < bytesNeeded)
    {
        SetLastError(ERROR_MORE_DATA);
        return FALSE;
    }
    if (len <= 0x7f)
        *pbEncoded = (BYTE)len;
    else
    {
        DWORD i;

        *pbEncoded++ = significantBytes | 0x80;
        for (i = 0; i < significantBytes; i++)
        {
            *(pbEncoded + significantBytes - i - 1) = (BYTE)(len & 0xff);
            len >>= 8;
        }
    }
    *pcbEncoded = bytesNeeded;
    return TRUE;
}

struct AsnEncodeSequenceItem
{
    const void             *pvStructInfo;
    CryptEncodeObjectExFunc encodeFunc;
    DWORD                   size; /* used during encoding, not for your use */
};

static BOOL WINAPI CRYPT_AsnEncodeSequence(DWORD dwCertEncodingType,
 struct AsnEncodeSequenceItem items[], DWORD cItem, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded)
{
    BOOL ret;
    DWORD i, dataLen = 0;

    TRACE("%p, %ld, %08lx, %p, %p, %ld\n", items, cItem, dwFlags, pEncodePara,
     pbEncoded, *pcbEncoded);
    for (i = 0, ret = TRUE; ret && i < cItem; i++)
    {
        ret = items[i].encodeFunc(dwCertEncodingType, NULL,
         items[i].pvStructInfo, dwFlags & ~CRYPT_ENCODE_ALLOC_FLAG, NULL,
         NULL, &items[i].size);
        /* Some functions propagate their errors through the size */
        if (!ret)
            *pcbEncoded = items[i].size;
        dataLen += items[i].size;
    }
    if (ret)
    {
        DWORD lenBytes, bytesNeeded;

        CRYPT_EncodeLen(dataLen, NULL, &lenBytes);
        bytesNeeded = 1 + lenBytes + dataLen;
        if (!pbEncoded)
            *pcbEncoded = bytesNeeded;
        else
        {
            if ((ret = CRYPT_EncodeEnsureSpace(dwFlags, pEncodePara, pbEncoded,
             pcbEncoded, bytesNeeded)))
            {
                if (dwFlags & CRYPT_ENCODE_ALLOC_FLAG)
                    pbEncoded = *(BYTE **)pbEncoded;
                *pbEncoded++ = ASN_SEQUENCE;
                CRYPT_EncodeLen(dataLen, pbEncoded, &lenBytes);
                pbEncoded += lenBytes;
                for (i = 0; ret && i < cItem; i++)
                {
                    ret = items[i].encodeFunc(dwCertEncodingType, NULL,
                     items[i].pvStructInfo, dwFlags & ~CRYPT_ENCODE_ALLOC_FLAG,
                     NULL, pbEncoded, &items[i].size);
                    /* Some functions propagate their errors through the size */
                    if (!ret)
                        *pcbEncoded = items[i].size;
                    pbEncoded += items[i].size;
                }
            }
        }
    }
    TRACE("returning %d (%08lx)\n", ret, GetLastError());
    return ret;
}

struct AsnConstructedItem
{
    BYTE                    tag;
    const void             *pvStructInfo;
    CryptEncodeObjectExFunc encodeFunc;
};

static BOOL WINAPI CRYPT_AsnEncodeConstructed(DWORD dwCertEncodingType,
 LPCSTR lpszStructType, const void *pvStructInfo, DWORD dwFlags,
 PCRYPT_ENCODE_PARA pEncodePara, BYTE *pbEncoded, DWORD *pcbEncoded)
{
    BOOL ret;
    const struct AsnConstructedItem *item =
     (const struct AsnConstructedItem *)pvStructInfo;
    DWORD len;

    if ((ret = item->encodeFunc(dwCertEncodingType, lpszStructType,
     item->pvStructInfo, dwFlags & ~CRYPT_ENCODE_ALLOC_FLAG, NULL, NULL, &len)))
    {
        DWORD dataLen, bytesNeeded;

        CRYPT_EncodeLen(len, NULL, &dataLen);
        bytesNeeded = 1 + dataLen + len;
        if (!pbEncoded)
            *pcbEncoded = bytesNeeded;
        else if ((ret = CRYPT_EncodeEnsureSpace(dwFlags, pEncodePara,
         pbEncoded, pcbEncoded, bytesNeeded)))