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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Functions to parse and manipulate the additional data tables added
* to optimized .dex files.
*/
#include <zlib.h>
#include "DexOptData.h"
/*
* Check to see if a given data pointer is a valid double-word-aligned
* pointer into the given memory range (from start inclusive to end
* exclusive). Returns true if valid.
*/
static bool isValidPointer(const void* ptr, const void* start, const void* end)
{
return (ptr >= start) && (ptr < end) && (((u4) ptr & 7) == 0);
}
/* (documented in header file) */
u4 dexComputeOptChecksum(const DexOptHeader* pOptHeader)
{
const u1* start = (const u1*) pOptHeader + pOptHeader->depsOffset;
const u1* end = (const u1*) pOptHeader +
pOptHeader->optOffset + pOptHeader->optLength;
uLong adler = adler32(0L, Z_NULL, 0);
return (u4) adler32(adler, start, end - start);
}
/* (documented in header file) */
bool dexParseOptData(const u1* data, size_t length, DexFile* pDexFile)
{
const void* pOptStart = data + pDexFile->pOptHeader->optOffset;
const void* pOptEnd = data + length;
const u4* pOpt = (const u4*) pOptStart;
u4 optLength = (const u1*) pOptEnd - (const u1*) pOptStart;
/*
* Make sure the opt data start is in range and aligned. This may
* seem like a superfluous check, but (a) if the file got
* truncated, it might turn out that pOpt >= pOptEnd; and (b)
* if the opt data header got corrupted, pOpt might not be
* properly aligned. This test will catch both of these cases.
*/
if (!isValidPointer(pOpt, pOptStart, pOptEnd)) {
LOGE("Bogus opt data start pointer");
return false;
}
/* Make sure that the opt data length is a whole number of words. */
if ((optLength & 3) != 0) {
LOGE("Unaligned opt data area end");
return false;
}
/*
* Make sure that the opt data area is large enough to have at least
* one chunk header.
*/
if (optLength < 8) {
LOGE("Undersized opt data area (%u)", optLength);
return false;
}
/* Process chunks until we see the end marker. */
while (*pOpt != kDexChunkEnd) {
if (!isValidPointer(pOpt + 2, pOptStart, pOptEnd)) {
LOGE("Bogus opt data content pointer at offset %u",
((const u1*) pOpt) - data);
return false;
}
u4 size = *(pOpt + 1);
const u1* pOptData = (const u1*) (pOpt + 2);
/*
* The rounded size is 64-bit aligned and includes +8 for the
* type/size header (which was extracted immediately above).
*/
u4 roundedSize = (size + 8 + 7) & ~7;
const u4* pNextOpt = pOpt + (roundedSize / sizeof(u4));
if (!isValidPointer(pNextOpt, pOptStart, pOptEnd)) {
LOGE("Opt data area problem for chunk of size %u at offset %u",
size, ((const u1*) pOpt) - data);
return false;
}
switch (*pOpt) {
case kDexChunkClassLookup:
pDexFile->pClassLookup = (const DexClassLookup*) pOptData;
break;
case kDexChunkRegisterMaps:
ALOGV("+++ found register maps, size=%u", size);
pDexFile->pRegisterMapPool = pOptData;
break;
default:
LOGI("Unknown chunk 0x%08x (%c%c%c%c), size=%d in opt data area",
*pOpt,
(char) ((*pOpt) >> 24), (char) ((*pOpt) >> 16),
(char) ((*pOpt) >> 8), (char) (*pOpt),
size);
break;
}
pOpt = pNextOpt;
}
return true;
}
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