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/*
* Copyright (C) 2008 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 deal with class definition structures in DEX files
*/
#include <stdlib.h>
#include <string.h>
#include "DexClass.h"
#include "Leb128.h"
/* Helper for verification which reads and verifies a given number
* of uleb128 values. */
static bool verifyUlebs(const u1* pData, const u1* pLimit, u4 count) {
bool okay = true;
while (okay && (count-- != 0)) {
readAndVerifyUnsignedLeb128(&pData, pLimit, &okay);
}
return okay;
}
/* Read and verify the header of a class_data_item. This updates the
* given data pointer to point past the end of the read data and
* returns an "okay" flag (that is, false == failure). */
bool dexReadAndVerifyClassDataHeader(const u1** pData, const u1* pLimit,
DexClassDataHeader *pHeader) {
if (! verifyUlebs(*pData, pLimit, 4)) {
return false;
}
dexReadClassDataHeader(pData, pHeader);
return true;
}
/* Read and verify an encoded_field. This updates the
* given data pointer to point past the end of the read data and
* returns an "okay" flag (that is, false == failure).
*
* The lastIndex value should be set to 0 before the first field in
* a list is read. It is updated as fields are read and used in the
* decode process.
*
* The verification done by this function is of the raw data format
* only; it does not verify that access flags or indices
* are valid. */
bool dexReadAndVerifyClassDataField(const u1** pData, const u1* pLimit,
DexField* pField, u4* lastIndex) {
if (! verifyUlebs(*pData, pLimit, 2)) {
return false;
}
dexReadClassDataField(pData, pField, lastIndex);
return true;
}
/* Read and verify an encoded_method. This updates the
* given data pointer to point past the end of the read data and
* returns an "okay" flag (that is, false == failure).
*
* The lastIndex value should be set to 0 before the first method in
* a list is read. It is updated as fields are read and used in the
* decode process.
*
* The verification done by this function is of the raw data format
* only; it does not verify that access flags, indices, or offsets
* are valid. */
bool dexReadAndVerifyClassDataMethod(const u1** pData, const u1* pLimit,
DexMethod* pMethod, u4* lastIndex) {
if (! verifyUlebs(*pData, pLimit, 3)) {
return false;
}
dexReadClassDataMethod(pData, pMethod, lastIndex);
return true;
}
/* Read, verify, and return an entire class_data_item. This updates
* the given data pointer to point past the end of the read data. This
* function allocates a single chunk of memory for the result, which
* must subsequently be free()d. This function returns NULL if there
* was trouble parsing the data. If this function is passed NULL, it
* returns an initialized empty DexClassData structure.
*
* The verification done by this function is of the raw data format
* only; it does not verify that access flags, indices, or offsets
* are valid. */
DexClassData* dexReadAndVerifyClassData(const u1** pData, const u1* pLimit) {
DexClassDataHeader header;
u4 lastIndex;
if (*pData == NULL) {
DexClassData* result = (DexClassData*) malloc(sizeof(DexClassData));
memset(result, 0, sizeof(*result));
return result;
}
if (! dexReadAndVerifyClassDataHeader(pData, pLimit, &header)) {
return NULL;
}
size_t resultSize = sizeof(DexClassData) +
(header.staticFieldsSize * sizeof(DexField)) +
(header.instanceFieldsSize * sizeof(DexField)) +
(header.directMethodsSize * sizeof(DexMethod)) +
(header.virtualMethodsSize * sizeof(DexMethod));
DexClassData* result = (DexClassData*) malloc(resultSize);
u1* ptr = ((u1*) result) + sizeof(DexClassData);
bool okay = true;
u4 i;
if (result == NULL) {
return NULL;
}
result->header = header;
if (header.staticFieldsSize != 0) {
result->staticFields = (DexField*) ptr;
ptr += header.staticFieldsSize * sizeof(DexField);
} else {
result->staticFields = NULL;
}
if (header.instanceFieldsSize != 0) {
result->instanceFields = (DexField*) ptr;
ptr += header.instanceFieldsSize * sizeof(DexField);
} else {
result->instanceFields = NULL;
}
if (header.directMethodsSize != 0) {
result->directMethods = (DexMethod*) ptr;
ptr += header.directMethodsSize * sizeof(DexMethod);
} else {
result->directMethods = NULL;
}
if (header.virtualMethodsSize != 0) {
result->virtualMethods = (DexMethod*) ptr;
} else {
result->virtualMethods = NULL;
}
lastIndex = 0;
for (i = 0; okay && (i < header.staticFieldsSize); i++) {
okay = dexReadAndVerifyClassDataField(pData, pLimit,
&result->staticFields[i], &lastIndex);
}
lastIndex = 0;
for (i = 0; okay && (i < header.instanceFieldsSize); i++) {
okay = dexReadAndVerifyClassDataField(pData, pLimit,
&result->instanceFields[i], &lastIndex);
}
lastIndex = 0;
for (i = 0; okay && (i < header.directMethodsSize); i++) {
okay = dexReadAndVerifyClassDataMethod(pData, pLimit,
&result->directMethods[i], &lastIndex);
}
lastIndex = 0;
for (i = 0; okay && (i < header.virtualMethodsSize); i++) {
okay = dexReadAndVerifyClassDataMethod(pData, pLimit,
&result->virtualMethods[i], &lastIndex);
}
if (! okay) {
free(result);
return NULL;
}
return result;
}
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