/*
* 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.
*/
/*
* Byte-swapping and verification of dex files.
*/
#include "DexFile.h"
#include "DexClass.h"
#include "DexDataMap.h"
#include "DexProto.h"
#include "DexUtf.h"
#include "Leb128.h"
#include <safe_iop.h>
#include <zlib.h>
#include <stdlib.h>
#include <string.h>
#ifndef __BYTE_ORDER
# error "byte ordering not defined"
#endif
#if __BYTE_ORDER == __LITTLE_ENDIAN
# define SWAP2(_value) (_value)
# define SWAP4(_value) (_value)
# define SWAP8(_value) (_value)
#else
# define SWAP2(_value) endianSwapU2((_value))
# define SWAP4(_value) endianSwapU4((_value))
# define SWAP8(_value) endianSwapU8((_value))
static u2 endianSwapU2(u2 value) {
return (value >> 8) | (value << 8);
}
static u4 endianSwapU4(u4 value) {
/* ABCD --> CDAB --> DCBA */
value = (value >> 16) | (value << 16);
return ((value & 0xff00ff00) >> 8) | ((value << 8) & 0xff00ff00);
}
static u8 endianSwapU8(u8 value) {
/* ABCDEFGH --> EFGHABCD --> GHEFCDAB --> HGFEDCBA */
value = (value >> 32) | (value << 32);
value = ((value & 0xffff0000ffff0000ULL) >> 16) |
((value << 16) & 0xffff0000ffff0000ULL);
return ((value & 0xff00ff00ff00ff00ULL) >> 8) |
((value << 8) & 0xff00ff00ff00ff00ULL);
}
#endif
#define SWAP_FIELD2(_field) (_field) = SWAP2(_field)
#define SWAP_FIELD4(_field) (_field) = SWAP4(_field)
#define SWAP_FIELD8(_field) (_field) = SWAP8(_field)
/*
* Some information we pass around to help verify values.
*/
struct CheckState {
const DexHeader* pHeader;
const u1* fileStart;
const u1* fileEnd; // points to fileStart + fileLen
u4 fileLen;
DexDataMap* pDataMap; // set after map verification
const DexFile* pDexFile; // set after intraitem verification
/*
* bitmap of type_id indices that have been used to define classes;
* initialized immediately before class_def cross-verification, and
* freed immediately after it
*/
u4* pDefinedClassBits;
const void* previousItem; // set during section iteration
};
/*
* Return the file offset of the given pointer.
*/
static inline u4 fileOffset(const CheckState* state, const void* ptr) {
return ((const u1*) ptr) - state->fileStart;
}
/*
* Return a pointer for the given file offset.
*/
static inline void* filePointer(const CheckState* state, u4 offset) {
return (void*) (state->fileStart + offset);
}
/*
* Verify that a pointer range, start inclusive to end exclusive, only
* covers bytes in the file and doesn't point beyond the end of the
* file. That is, the start must indicate a valid byte or may point at
* the byte just past the end of the file (but no further), and the
* end must be no less than the start and must also not point beyond
* the byte just past the end of the file.
*/
static inline bool checkPtrRange(const CheckState* state,
const void* start, const void* end, const char* label) {
const void* fileStart = state->fileStart;
const void* fileEnd = state->fileEnd;
if ((start < fileStart) || (start > fileEnd)
|| (end < start) || (end > fileEnd)) {
ALOGW("Bad offset range for %s: %#x..%#x", label,
fileOffset(state, start), fileOffset(state, end));
return false;
}
return true;
}
/*
* Verify that a range of offsets, start inclusive to end exclusive,
* are all valid. That is, the start must indicate a valid byte or may
* point at the byte just past the end of the file (but no further),
* and the end must be no less than the start and must also not point
* beyond the byte just past the end of the file.
*
* Assumes "const CheckState* state".
*/
#define CHECK_OFFSET_RANGE(_start, _end) { \
const u1* _startPtr = (const u1*) filePointer(state, (_start)); \
const u1* _endPtr = (const u1*) filePointer(state, (_end)); \
if (!checkPtrRange(state, _startPtr, _endPtr, \
#_start ".." #_end)) { \
return 0; \
} \
}
/*
* Verify that a pointer range, start inclusive to end exclusive, only
* covers bytes in the file and doesn't point beyond the end of the
* file. That is, the start must indicate a valid byte or may point at
* the byte just past the end of the file (but no further), and the
* end must be no less than the start and must also not point beyond
* the byte just past the end of the file.
*
* Assumes "const CheckState* state".
*/
#define CHECK_PTR_RANGE(_start, _end) { \
if (!checkPtrRange(state, (_start), (_end), #_start ".." #_end)) { \
return 0; \
} \
}
/*
* Make sure a list of items fits entirely within the file.
*
* Assumes "const CheckState* state" and "typeof(_count) == typeof(_elemSize)"
* If the type sizes or signs are mismatched, this will return 0.
*/
#define CHECK_LIST_SIZE(_ptr, _count, _elemSize) { \
const u1* _start = (const u1*) (_ptr); \
const u1* _end = _start + ((_count) * (_elemSize)); \
if (!safe_mul(NULL, (_count), (_elemSize)) || \
!checkPtrRange(state, _start, _end, #_ptr)) { \
return 0; \
} \
}
/*
* Swap a field that is known to hold an absolute DEX file offset. Note:
* This does not check to see that the swapped offset points within the
* mapped file, since that should be handled (with even more rigor) by
* the cross-verification phase.
*
* Assumes "const CheckState* state".
*/
#define SWAP_OFFSET4(_field) { \
SWAP_FIELD4((_field)); \
}
/*
* Verify that an index falls in a valid range.
*/
#define CHECK_INDEX(_field, _limit) { \
if ((_field) >= (_limit)) { \
ALOGW("Bad index: %s(%u) > %s(%u)", \
#_field, (u4)(_field), #_limit, (u4)(_limit)); \
return 0; \
} \
}
/*
* Swap an index, and verify that it falls in a valid range.
*/
#define SWAP_INDEX2(_field, _limit) { \
SWAP_FIELD2((_field)); \
CHECK_INDEX((_field), (_limit)); \
}
/*
* Verify that an index falls in a valid range or is kDexNoIndex.
*/
#define CHECK_INDEX_OR_NOINDEX(_field, _limit) { \
if ((_field) != kDexNoIndex && (_field) >= (_limit)) { \
ALOGW("Bad index: %s(%u) > %s(%u)", \
#_field, (u4)(_field), #_limit, (u4)(_limit)); \
return 0; \
} \
}
/*
* Swap an index, and verify that it falls in a valid range.
*/
#define SWAP_INDEX4(_field, _limit) { \
SWAP_FIELD4((_field)); \
CHECK_INDEX((_field), (_limit)); \
}
/*
* Swap an index, and verify that it falls in a valid range or is
* kDexNoIndex.
*/
#define SWAP_INDEX4_OR_NOINDEX(_field, _limit) { \
SWAP_FIELD4((_field)); \
CHECK_INDEX_OR_NOINDEX((_field), (_limit)); \
}
/* Verify the definer of a given field_idx. */
static bool verifyFieldDefiner(const CheckState* state, u4 definingClass,
u4 fieldIdx) {
const DexFieldId* field = dexGetFieldId(state->pDexFile, fieldIdx);
return field->classIdx == definingClass;
}
/* Verify the definer of a given method_idx. */
static bool verifyMethodDefiner(const CheckState* state, u4 definingClass,
u4 methodIdx) {
const DexMethodId* meth = dexGetMethodId(state->pDexFile, methodIdx);
return meth->classIdx == definingClass;
}
/*
* Calculate the required size (in elements) of the array pointed at by
* pDefinedClassBits.
*/
static size_t calcDefinedClassBitsSize(const CheckState* state)
{
// Divide typeIdsSize by 32 (0x20), rounding up.
return (state->pHeader->typeIdsSize + 0x1f) >> 5;
}
/*
* Set the given bit in pDefinedClassBits, returning its former value.
*/
static bool setDefinedClassBit(const CheckState* state, u4 typeIdx) {
u4 arrayIdx = typeIdx >> 5;
u4 bit = 1 << (typeIdx & 0x1f);
u4* element = &state->pDefinedClassBits[arrayIdx];
bool result = (*element & bit) != 0;
*element |= bit;
return result;
}
/*
* Swap the header_item.
*/
static bool swapDexHeader(const CheckState* state, DexHeader* pHeader)
{
CHECK_PTR_RANGE(pHeader, pHeader + 1);
// magic is ok
SWAP_FIELD4(pHeader->checksum);
// signature is ok
SWAP_FIELD4(pHeader->fileSize);
SWAP_FIELD4(pHeader->headerSize);
SWAP_FIELD4(pHeader->endianTag);
SWAP_FIELD4(pHeader->linkSize);
SWAP_OFFSET4(pHeader->linkOff);
SWAP_OFFSET4(pHeader->mapOff);
SWAP_FIELD4(pHeader->stringIdsSize);
SWAP_OFFSET4(pHeader->stringIdsOff);
SWAP_FIELD4(pHeader->typeIdsSize);
SWAP_OFFSET4(pHeader->typeIdsOff);
SWAP_FIELD4(pHeader->fieldIdsSize);
SWAP_OFFSET4(pHeader->fieldIdsOff);
SWAP_FIELD4(pHeader->methodIdsSize);
SWAP_OFFSET4(pHeader->methodIdsOff);
SWAP_FIELD4(pHeader->protoIdsSize);
SWAP_OFFSET4(pHeader->protoIdsOff);
SWAP_FIELD4(pHeader->classDefsSize);
SWAP_OFFSET4(pHeader->classDefsOff);
SWAP_FIELD4(pHeader->dataSize);
SWAP_OFFSET4(pHeader->dataOff);
if (pHeader->endianTag != kDexEndianConstant) {
ALOGE("Unexpected endian_tag: %#x", pHeader->endianTag);
return false;
}
// Assign variables so the diagnostic is prettier. (Hooray for macros.)
u4 linkOff = pHeader->linkOff;
u4 linkEnd = linkOff + pHeader->linkSize;
u4 dataOff = pHeader->dataOff;
u4 dataEnd = dataOff + pHeader->dataSize;
CHECK_OFFSET_RANGE(linkOff, linkEnd);
CHECK_OFFSET_RANGE(dataOff, dataEnd);
/*
* Note: The offsets and ranges of the other header items end up getting
* checked during the first iteration over the map.
*/
return true;
}
/* Check the header section for sanity. */
static bool checkHeaderSection(const CheckState* state, u4 sectionOffset,
u4 sectionCount, u4* endOffset) {
if (sectionCount != 1) {
ALOGE("Multiple header items");
return false;
}
if (sectionOffset != 0) {
ALOGE("Header at %#x; not at start of file", sectionOffset);
return false;
}
const DexHeader* pHeader = (const DexHeader*) filePointer(state, 0);
*endOffset = pHeader->headerSize;
return true;
}
/*
* Helper for swapMap(), which turns a map type constant into a small
* one-bit-on integer, suitable for use in an int-sized bit set.
*/
static u4 mapTypeToBitMask(int mapType) {
switch (mapType) {
case kDexTypeHeaderItem: return 1 << 0;
case kDexTypeStringIdItem: return 1 << 1;
case kDexTypeTypeIdItem: return 1 << 2;
case kDexTypeProtoIdItem: return 1 << 3;
case kDexTypeFieldIdItem: return 1 << 4;
case kDexTypeMethodIdItem: return 1 << 5;
case kDexTypeClassDefItem: return 1 << 6;
case kDexTypeMapList: return 1 << 7;
case kDexTypeTypeList: return 1 << 8;
case kDexTypeAnnotationSetRefList: return 1 << 9;
case kDexTypeAnnotationSetItem: return 1 << 10;
case kDexTypeClassDataItem: return 1 << 11;
case kDexTypeCodeItem: return 1 << 12;
case kDexTypeStringDataItem: return 1 << 13;
case kDexTypeDebugInfoItem: return 1 << 14;
case kDexTypeAnnotationItem: return 1 << 15;
case kDexTypeEncodedArrayItem: return 1 << 16;
case kDexTypeAnnotationsDirectoryItem: return 1 << 17;
default: {
ALOGE("Unknown map item type %04x", mapType);
return 0;
}
}
}
/*
* Helper for swapMap(), which indicates if an item type should appear
* in the data section.
*/
static bool isDataSectionType(int mapType) {
switch (mapType) {
case kDexTypeHeaderItem:
case kDexTypeStringIdItem:
case kDexTypeTypeIdItem:
case kDexTypeProtoIdItem:
case kDexTypeFieldIdItem:
case kDexTypeMethodIdItem:
case kDexTypeClassDefItem: {
return false;
}
}
return true;
}
/*
* Swap the map_list and verify what we can about it. Also, if verification
* passes, allocate the state's DexDataMap.
*/
static bool swapMap(CheckState* state, DexMapList* pMap)
{
DexMapItem* item = pMap->list;
u4 count;
u4 dataItemCount = 0; // Total count of items in the data section.
u4 dataItemsLeft = state->pHeader->dataSize; // See use below.
u4 usedBits = 0; // Bit set: one bit per section
bool first = true;
u4 lastOffset = 0;
SWAP_FIELD4(pMap->size);
count = pMap->size;
CHECK_LIST_SIZE(item, count, sizeof(DexMapItem));
while (count--) {
SWAP_FIELD2(item->type);
SWAP_FIELD2(item->unused);
SWAP_FIELD4(item->size);
SWAP_OFFSET4(item->offset);
if (first) {
first = false;
} else if (lastOffset >= item->offset) {
ALOGE("Out-of-order map item: %#x then %#x",
lastOffset, item->offset);
return false;
}
if (item->offset >= state->pHeader->fileSize) {
ALOGE("Map item after end of file: %x, size %#x",
item->offset, state->pHeader->fileSize);
return false;
}
if (isDataSectionType(item->type)) {
u4 icount = item->size;
/*
* This sanity check on the data section items ensures that
* there are no more items than the number of bytes in
* the data section.
*/
if (icount > dataItemsLeft) {
ALOGE("Unrealistically many items in the data section: "
"at least %d", dataItemCount + icount);
return false;
}
dataItemsLeft -= icount;
dataItemCount += icount;
}
u4 bit = mapTypeToBitMask(item->type);
if (bit == 0) {
return false;
}
if ((usedBits & bit) != 0) {
ALOGE("Duplicate map section of type %#x", item->type);
return false;
}
usedBits |= bit;
lastOffset = item->offset;
item++;
}
if ((usedBits & mapTypeToBitMask(kDexTypeHeaderItem)) == 0) {
ALOGE("Map is missing header entry");
return false;
}
if ((usedBits & mapTypeToBitMask(kDexTypeMapList)) == 0) {
ALOGE("Map is missing map_list entry");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeStringIdItem)) == 0)
&& ((state->pHeader->stringIdsOff != 0)
|| (state->pHeader->stringIdsSize != 0))) {
ALOGE("Map is missing string_ids entry");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeTypeIdItem)) == 0)
&& ((state->pHeader->typeIdsOff != 0)
|| (state->pHeader->typeIdsSize != 0))) {
ALOGE("Map is missing type_ids entry");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeProtoIdItem)) == 0)
&& ((state->pHeader->protoIdsOff != 0)
|| (state->pHeader->protoIdsSize != 0))) {
ALOGE("Map is missing proto_ids entry");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeFieldIdItem)) == 0)
&& ((state->pHeader->fieldIdsOff != 0)
|| (state->pHeader->fieldIdsSize != 0))) {
ALOGE("Map is missing field_ids entry");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeMethodIdItem)) == 0)
&& ((state->pHeader->methodIdsOff != 0)
|| (state->pHeader->methodIdsSize != 0))) {
ALOGE("Map is missing method_ids entry");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeClassDefItem)) == 0)
&& ((state->pHeader->classDefsOff != 0)
|| (state->pHeader->classDefsSize != 0))) {
ALOGE("Map is missing class_defs entry");
return false;
}
state->pDataMap = dexDataMapAlloc(dataItemCount);
if (state->pDataMap == NULL) {
ALOGE("Unable to allocate data map (size %#x)", dataItemCount);
return false;
}
return true;
}
/* Check the map section for sanity. */
static bool checkMapSection(const CheckState* state, u4 sectionOffset,
u4 sectionCount, u4* endOffset) {
if (sectionCount != 1) {
ALOGE("Multiple map list items");
return false;
}
if (sectionOffset != state->pHeader->mapOff) {
ALOGE("Map not at header-defined offset: %#x, expected %#x",
sectionOffset, state->pHeader->mapOff);
return false;
}
const DexMapList* pMap = (const DexMapList*) filePointer(state, sectionOffset);
*endOffset =
sectionOffset + sizeof(u4) + (pMap->size * sizeof(DexMapItem));
return true;
}
/* Perform byte-swapping and intra-item verification on string_id_item. */
static void* swapStringIdItem(const CheckState* state, void* ptr) {
DexStringId* item = (DexStringId*) ptr;
CHECK_PTR_RANGE(item, item + 1);
SWAP_OFFSET4(item->stringDataOff);
return item + 1;
}
/* Perform cross-item verification of string_id_item. */
static void* crossVerifyStringIdItem(const CheckState* state, void* ptr) {
const DexStringId* item = (const DexStringId*) ptr;
if (!dexDataMapVerify(state->pDataMap,
item->stringDataOff, kDexTypeStringDataItem)) {
return NULL;
}
const DexStringId* item0 = (const DexStringId*) state->previousItem;
if (item0 != NULL) {
// Check ordering.
const char* s0 = dexGetStringData(state->pDexFile, item0);
const char* s1 = dexGetStringData(state->pDexFile, item);
if (dexUtf8Cmp(s0, s1) >= 0) {
ALOGE("Out-of-order string_ids: '%s' then '%s'", s0, s1);
return NULL;
}
}
return (void*) (item + 1);
}
/* Perform byte-swapping and intra-item verification on type_id_item. */
static void* swapTypeIdItem(const CheckState* state, void* ptr) {
DexTypeId* item = (DexTypeId*) ptr;
CHECK_PTR_RANGE(item, item + 1);
SWAP_INDEX4(item->descriptorIdx, state->pHeader->stringIdsSize);
return item + 1;
}
/* Perform cross-item verification of type_id_item. */
static void* crossVerifyTypeIdItem(const CheckState* state, void* ptr) {
const DexTypeId* item = (const DexTypeId*) ptr;
const char* descriptor =
dexStringById(state->pDexFile, item->descriptorIdx);
if (!dexIsValidTypeDescriptor(descriptor)) {
ALOGE("Invalid type descriptor: '%s'", descriptor);
return NULL;
}
const DexTypeId* item0 = (const DexTypeId*) state->previousItem;
if (item0 != NULL) {
// Check ordering. This relies on string_ids being in order.
if (item0->descriptorIdx >= item->descriptorIdx) {
ALOGE("Out-of-order type_ids: %#x then %#x",
item0->descriptorIdx, item->descriptorIdx);
return NULL;
}
}
return (void*) (item + 1);
}
/* Perform byte-swapping and intra-item verification on proto_id_item. */
static void* swapProtoIdItem(const CheckState* state, void* ptr) {
DexProtoId* item = (DexProtoId*) ptr;
CHECK_PTR_RANGE(item, item + 1);
SWAP_INDEX4(item->shortyIdx, state->pHeader->stringIdsSize);
SWAP_INDEX4(item->returnTypeIdx, state->pHeader->typeIdsSize);
SWAP_OFFSET4(item->parametersOff);
return item + 1;
}
/* Helper for crossVerifyProtoIdItem(), which checks a shorty character
* to see if it is compatible with a type descriptor. Returns true if
* so, false if not. */
static bool shortyDescMatch(char shorty, const char* descriptor, bool
isReturnType) {
switch (shorty) {
case 'V': {
if (!isReturnType) {
ALOGE("Invalid use of void");
return false;
}
// Fall through.
}
case 'B':
case 'C':
case 'D':
case 'F':
case 'I':
case 'J':
case 'S':
case 'Z': {
if ((descriptor[0] != shorty) || (descriptor[1] != '\0')) {
ALOGE("Shorty vs. primitive type mismatch: '%c', '%s'",
shorty, descriptor);
return false;
}
break;
}
case 'L': {
if ((descriptor[0] != 'L') && (descriptor[0] != '[')) {
ALOGE("Shorty vs. type mismatch: '%c', '%s'",
shorty, descriptor);
return false;
}
break;
}
default: {
ALOGE("Bogus shorty: '%c'", shorty);
return false;
}
}
return true;
}
/* Perform cross-item verification of proto_id_item. */
static void* crossVerifyProtoIdItem(const CheckState* state, void* ptr) {
const DexProtoId* item = (const DexProtoId*) ptr;
const char* shorty =
dexStringById(state->pDexFile, item->shortyIdx);
if (!dexDataMapVerify0Ok(state->pDataMap,
item->parametersOff, kDexTypeTypeList)) {
return NULL;
}
if (!shortyDescMatch(*shorty,
dexStringByTypeIdx(state->pDexFile, item->returnTypeIdx),
true)) {
return NULL;
}
u4 protoIdx = item - state->pDexFile->pProtoIds;
DexProto proto = { state->pDexFile, protoIdx };
DexParameterIterator iterator;
dexParameterIteratorInit(&iterator, &proto);
shorty++; // Skip the return type.
for (;;) {
const char *desc = dexParameterIteratorNextDescriptor(&iterator);
if (desc == NULL) {
break;
}
if (*shorty == '\0') {
ALOGE("Shorty is too short");
return NULL;
}
if (!shortyDescMatch(*shorty, desc, false)) {
return NULL;
}
shorty++;
}
if (*shorty != '\0') {
ALOGE("Shorty is too long");
return NULL;
}
const DexProtoId* item0 = (const DexProtoId*) state->previousItem;
if (item0 != NULL) {
// Check ordering. This relies on type_ids being in order.
if (item0->returnTypeIdx > item->returnTypeIdx) {
ALOGE("Out-of-order proto_id return types");
return NULL;
} else if (item0->returnTypeIdx == item->returnTypeIdx) {
bool badOrder = false;
DexProto proto0 = { state->pDexFile, protoIdx - 1 };
DexParameterIterator iterator0;
dexParameterIteratorInit(&iterator, &proto);
dexParameterIteratorInit(&iterator0, &proto0);
for (;;) {
u4 idx0 = dexParameterIteratorNextIndex(&iterator0);
u4 idx1 = dexParameterIteratorNextIndex(&iterator);
if (idx1 == kDexNoIndex) {
badOrder = true;
break;
}
if (idx0 == kDexNoIndex) {
break;
}
if (idx0 < idx1) {
break;
} else if (idx0 > idx1) {
badOrder = true;
break;
}
}
if (badOrder) {
ALOGE("Out-of-order proto_id arguments");
return NULL;
}
}
}
return (void*) (item + 1);
}
/* Perform byte-swapping and intra-item verification on field_id_item. */
static void* swapFieldIdItem(const CheckState* state, void* ptr) {
DexFieldId* item = (DexFieldId*) ptr;
CHECK_PTR_RANGE(item, item + 1);
SWAP_INDEX2(item->classIdx, state->pHeader->typeIdsSize);
SWAP_INDEX2(item->typeIdx, state->pHeader->typeIdsSize);
SWAP_INDEX4(item->nameIdx, state->pHeader->stringIdsSize);
return item + 1;
}
/* Perform cross-item verification of field_id_item. */
static void* crossVerifyFieldIdItem(const CheckState* state, void* ptr) {
const DexFieldId* item = (const DexFieldId*) ptr;
const char* s;
s = dexStringByTypeIdx(state->pDexFile, item->classIdx);
if (!dexIsClassDescriptor(s)) {
ALOGE("Invalid descriptor for class_idx: '%s'", s);
return NULL;
}
s = dexStringByTypeIdx(state->pDexFile, item->typeIdx);
if (!dexIsFieldDescriptor(s)) {
ALOGE("Invalid descriptor for type_idx: '%s'", s);
return NULL;
}
s = dexStringById(state->pDexFile, item->nameIdx);
if (!dexIsValidMemberName(s)) {
ALOGE("Invalid name: '%s'", s);
return NULL;
}
const DexFieldId* item0 = (const DexFieldId*) state->previousItem;
if (item0 != NULL) {
// Check ordering. This relies on the other sections being in order.
bool done = false;
bool bogus = false;
if (item0->classIdx > item->classIdx) {
bogus = true;
done = true;
} else if (item0->classIdx < item->classIdx) {
done = true;
}
if (!done) {
if (item0->nameIdx > item->nameIdx) {
bogus = true;
done = true;
} else if (item0->nameIdx < item->nameIdx) {
done = true;
}
}
if (!done) {
if (item0->typeIdx >= item->typeIdx) {
bogus = true;
}
}
if (bogus) {
ALOGE("Out-of-order field_ids");
return NULL;
}
}
return (void*) (item + 1);
}
/* Perform byte-swapping and intra-item verification on method_id_item. */
static void* swapMethodIdItem(const CheckState* state, void* ptr) {
DexMethodId* item = (DexMethodId*) ptr;
CHECK_PTR_RANGE(item, item + 1);
SWAP_INDEX2(item->classIdx, state->pHeader->typeIdsSize);
SWAP_INDEX2(item->protoIdx, state->pHeader->protoIdsSize);
SWAP_INDEX4(item->nameIdx, state->pHeader->stringIdsSize);
return item + 1;
}
/* Perform cross-item verification of method_id_item. */
static void* crossVerifyMethodIdItem(const CheckState* state, void* ptr) {
const DexMethodId* item = (const DexMethodId*) ptr;
const char* s;
s = dexStringByTypeIdx(state->pDexFile, item->classIdx);
if (!dexIsReferenceDescriptor(s)) {
ALOGE("Invalid descriptor for class_idx: '%s'", s);
return NULL;
}
s = dexStringById(state->pDexFile, item->nameIdx);
if (!dexIsValidMemberName(s)) {
ALOGE("Invalid name: '%s'", s);
return NULL;
}
const DexMethodId* item0 = (const DexMethodId*) state->previousItem;
if (item0 != NULL) {
// Check ordering. This relies on the other sections being in order.
bool done = false;
bool bogus = false;
if (item0->classIdx > item->classIdx) {
bogus = true;
done = true;
} else if (item0->classIdx < item->classIdx) {
done = true;
}
if (!done) {
if (item0->nameIdx > item->nameIdx) {
bogus = true;
done = true;
} else if (item0->nameIdx < item->nameIdx) {
done = true;
}
}
if (!done) {
if (item0->protoIdx >= item->protoIdx) {
bogus = true;
}
}
if (bogus) {
ALOGE("Out-of-order method_ids");
return NULL;
}
}
return (void*) (item + 1);
}
/* Perform byte-swapping and intra-item verification on class_def_item. */
static void* swapClassDefItem(const CheckState* state, void* ptr) {
DexClassDef* item = (DexClassDef*) ptr;
CHECK_PTR_RANGE(item, item + 1);
SWAP_INDEX4(item->classIdx, state->pHeader->typeIdsSize);
SWAP_FIELD4(item->accessFlags);
SWAP_INDEX4_OR_NOINDEX(item->superclassIdx, state->pHeader->typeIdsSize);
SWAP_OFFSET4(item->interfacesOff);
SWAP_INDEX4_OR_NOINDEX(item->sourceFileIdx, state->pHeader->stringIdsSize);
SWAP_OFFSET4(item->annotationsOff);
SWAP_OFFSET4(item->classDataOff);
if ((item->accessFlags & ~ACC_CLASS_MASK) != 0) {
// The VM specification says that unknown flags should be ignored.
ALOGV("Bogus class access flags %x", item->accessFlags);
item->accessFlags &= ACC_CLASS_MASK;
}
return item + 1;
}
/* defined below */
static u4 findFirstClassDataDefiner(const CheckState* state,
DexClassData* classData);
static u4 findFirstAnnotationsDirectoryDefiner(const CheckState* state,
const DexAnnotationsDirectoryItem* dir);
/* Helper for crossVerifyClassDefItem(), which checks a class_data_item to
* make sure all its references are to a given class. */
static bool verifyClassDataIsForDef(const CheckState* state, u4 offset,
u4 definerIdx) {
if (offset == 0) {
return true;
}
const u1* data = (const u1*) filePointer(state, offset);
DexClassData* classData = dexReadAndVerifyClassData(&data, NULL);
if (classData == NULL) {
// Shouldn't happen, but bail here just in case.
return false;
}
/*
* The class_data_item verification ensures that
* it consistently refers to the same definer, so all we need to
* do is check the first one.
*/
u4 dataDefiner = findFirstClassDataDefiner(state, classData);
bool result = (dataDefiner == definerIdx) || (dataDefiner == kDexNoIndex);
free(classData);
return result;
}
/* Helper for crossVerifyClassDefItem(), which checks an
* annotations_directory_item to make sure all its references are to a
* given class. */
static bool verifyAnnotationsDirectoryIsForDef(const CheckState* state,
u4 offset, u4 definerIdx) {
if (offset == 0) {
return true;
}
const DexAnnotationsDirectoryItem* dir =
(const DexAnnotationsDirectoryItem*) filePointer(state, offset);
u4 annoDefiner = findFirstAnnotationsDirectoryDefiner(state, dir);
return (annoDefiner == definerIdx) || (annoDefiner == kDexNoIndex);
}
/* Perform cross-item verification of class_def_item. */
static void* crossVerifyClassDefItem(const CheckState* state, void* ptr) {
const DexClassDef* item = (const DexClassDef*) ptr;
u4 classIdx = item->classIdx;
const char* descriptor = dexStringByTypeIdx(state->pDexFile, classIdx);
if (!dexIsClassDescriptor(descriptor)) {
ALOGE("Invalid class: '%s'", descriptor);
return NULL;
}
if (setDefinedClassBit(state, classIdx)) {
ALOGE("Duplicate class definition: '%s'", descriptor);
return NULL;
}
bool okay =
dexDataMapVerify0Ok(state->pDataMap,
item->interfacesOff, kDexTypeTypeList)
&& dexDataMapVerify0Ok(state->pDataMap,
item->annotationsOff, kDexTypeAnnotationsDirectoryItem)
&& dexDataMapVerify0Ok(state->pDataMap,
item->classDataOff, kDexTypeClassDataItem)
&& dexDataMapVerify0Ok(state->pDataMap,
item->staticValuesOff, kDexTypeEncodedArrayItem);
if (!okay) {
return NULL;
}
if (item->superclassIdx != kDexNoIndex) {
descriptor = dexStringByTypeIdx(state->pDexFile, item->superclassIdx);
if (!dexIsClassDescriptor(descriptor)) {
ALOGE("Invalid superclass: '%s'", descriptor);
return NULL;
}
}
const DexTypeList* interfaces =
dexGetInterfacesList(state->pDexFile, item);
if (interfaces != NULL) {
u4 size = interfaces->size;
u4 i;
/*
* Ensure that all interfaces refer to classes (not arrays or
* primitives).
*/
for (i = 0; i < size; i++) {
descriptor = dexStringByTypeIdx(state->pDexFile,
dexTypeListGetIdx(interfaces, i));
if (!dexIsClassDescriptor(descriptor)) {
ALOGE("Invalid interface: '%s'", descriptor);
return NULL;
}
}
/*
* Ensure that there are no duplicates. This is an O(N^2) test,
* but in practice the number of interfaces implemented by any
* given class is low. I will buy a milkshake for the
* first person to show me a realistic case for which this test
* would be unacceptably slow.
*/
for (i = 1; i < size; i++) {
u4 idx1 = dexTypeListGetIdx(interfaces, i);
u4 j;
for (j = 0; j < i; j++) {
u4 idx2 = dexTypeListGetIdx(interfaces, j);
if (idx1 == idx2) {
ALOGE("Duplicate interface: '%s'",
dexStringByTypeIdx(state->pDexFile, idx1));
return NULL;
}
}
}
}
if (!verifyClassDataIsForDef(state, item->classDataOff, item->classIdx)) {
ALOGE("Invalid class_data_item");
return NULL;
}
if (!verifyAnnotationsDirectoryIsForDef(state, item->annotationsOff,
item->classIdx)) {
ALOGE("Invalid annotations_directory_item");
return NULL;
}
return (void*) (item + 1);
}
/* Helper for swapAnnotationsDirectoryItem(), which performs
* byte-swapping and intra-item verification on an
* annotation_directory_item's field elements. */
static u1* swapFieldAnnotations(const CheckState* state, u4 count, u1* addr) {
DexFieldAnnotationsItem* item = (DexFieldAnnotationsItem*) addr;
bool first = true;
u4 lastIdx = 0;
CHECK_LIST_SIZE(item, count, sizeof(DexFieldAnnotationsItem));
while (count--) {
SWAP_INDEX4(item->fieldIdx, state->pHeader->fieldIdsSize);
SWAP_OFFSET4(item->annotationsOff);
if (first) {
first = false;
} else if (lastIdx >= item->fieldIdx) {
ALOGE("Out-of-order field_idx: %#x then %#x", lastIdx,
item->fieldIdx);
return NULL;
}
lastIdx = item->fieldIdx;
item++;
}
return (u1*) item;
}
/* Helper for swapAnnotationsDirectoryItem(), which performs
* byte-swapping and intra-item verification on an
* annotation_directory_item's method elements. */
static u1* swapMethodAnnotations(const CheckState* state, u4 count, u1* addr) {
DexMethodAnnotationsItem* item = (DexMethodAnnotationsItem*) addr;
bool first = true;
u4 lastIdx = 0;
CHECK_LIST_SIZE(item, count, sizeof(DexMethodAnnotationsItem));
while (count--) {
SWAP_INDEX4(item->methodIdx, state->pHeader->methodIdsSize);
SWAP_OFFSET4(item->annotationsOff);
if (first) {
first = false;
} else if (lastIdx >= item->methodIdx) {
ALOGE("Out-of-order method_idx: %#x then %#x", lastIdx,
item->methodIdx);
return NULL;
}
lastIdx = item->methodIdx;
item++;
}
return (u1*) item;
}
/* Helper for swapAnnotationsDirectoryItem(), which performs
* byte-swapping and intra-item verification on an
* annotation_directory_item's parameter elements. */
static u1* swapParameterAnnotations(const CheckState* state, u4 count,
u1* addr) {
DexParameterAnnotationsItem* item = (DexParameterAnnotationsItem*) addr;
bool first = true;
u4 lastIdx = 0;
CHECK_LIST_SIZE(item, count, sizeof(DexParameterAnnotationsItem));
while (count--) {
SWAP_INDEX4(item->methodIdx, state->pHeader->methodIdsSize);
SWAP_OFFSET4(item->annotationsOff);
if (first) {
first = false;
} else if (lastIdx >= item->methodIdx) {
ALOGE("Out-of-order method_idx: %#x then %#x", lastIdx,
item->methodIdx);
return NULL;
}
lastIdx = item->methodIdx;
item++;
}
return (u1*) item;
}
/* Perform byte-swapping and intra-item verification on
* annotations_directory_item. */
static void* swapAnnotationsDirectoryItem(const CheckState* state, void* ptr) {
DexAnnotationsDirectoryItem* item = (DexAnnotationsDirectoryItem*) ptr;
CHECK_PTR_RANGE(item, item + 1);
SWAP_OFFSET4(item->classAnnotationsOff);
SWAP_FIELD4(item->fieldsSize);
SWAP_FIELD4(item->methodsSize);
SWAP_FIELD4(item->parametersSize);
u1* addr = (u1*) (item + 1);
if (item->fieldsSize != 0) {
addr = swapFieldAnnotations(state, item->fieldsSize, addr);
if (addr == NULL) {
return NULL;
}
}
if (item->methodsSize != 0) {
addr = swapMethodAnnotations(state, item->methodsSize, addr);
if (addr == NULL) {
return NULL;
}
}
if (item->parametersSize != 0) {
addr = swapParameterAnnotations(state, item->parametersSize, addr);
if (addr == NULL) {
return NULL;
}
}
return addr;
}
/* Helper for crossVerifyAnnotationsDirectoryItem(), which checks the
* field elements. */
static const u1* crossVerifyFieldAnnotations(const CheckState* state, u4 count,
const u1* addr, u4 definingClass) {
const DexFieldAnnotationsItem* item = (DexFieldAnnotationsItem*) addr;
while (count--) {
if (!verifyFieldDefiner(state, definingClass, item->fieldIdx)) {
return NULL;
}
if (!dexDataMapVerify(state->pDataMap, item->annotationsOff,
kDexTypeAnnotationSetItem)) {
return NULL;
}
item++;
}
return (const u1*) item;
}
/* Helper for crossVerifyAnnotationsDirectoryItem(), which checks the
* method elements. */
static const u1* crossVerifyMethodAnnotations(const CheckState* state,
u4 count, const u1* addr, u4 definingClass) {
const DexMethodAnnotationsItem* item = (DexMethodAnnotationsItem*) addr;
while (count--) {
if (!verifyMethodDefiner(state, definingClass, item->methodIdx)) {
return NULL;
}
if (!dexDataMapVerify(state->pDataMap, item->annotationsOff,
kDexTypeAnnotationSetItem)) {
return NULL;
}
item++;
}
return (const u1*) item;
}
/* Helper for crossVerifyAnnotationsDirectoryItem(), which checks the
* parameter elements. */
static const u1* crossVerifyParameterAnnotations(const CheckState* state,
u4 count, const u1* addr, u4 definingClass) {
const DexParameterAnnotationsItem* item =
(DexParameterAnnotationsItem*) addr;
while (count--) {
if (!verifyMethodDefiner(state, definingClass, item->methodIdx)) {
return NULL;
}
if (!dexDataMapVerify(state->pDataMap, item->annotationsOff,
kDexTypeAnnotationSetRefList)) {
return NULL;
}
item++;
}
return (const u1*) item;
}
/* Helper for crossVerifyClassDefItem() and
* crossVerifyAnnotationsDirectoryItem(), which finds the type_idx of
* the definer of the first item in the data. */
static u4 findFirstAnnotationsDirectoryDefiner(const CheckState* state,
const DexAnnotationsDirectoryItem* dir) {
if (dir->fieldsSize != 0) {
const DexFieldAnnotationsItem* fields =
dexGetFieldAnnotations(state->pDexFile, dir);
const DexFieldId* field =
dexGetFieldId(state->pDexFile, fields[0].fieldIdx);
return field->classIdx;
}
if (dir->methodsSize != 0) {
const DexMethodAnnotationsItem* methods =
dexGetMethodAnnotations(state->pDexFile, dir);
const DexMethodId* method =
dexGetMethodId(state->pDexFile, methods[0].methodIdx);
return method->classIdx;
}
if (dir->parametersSize != 0) {
const DexParameterAnnotationsItem* parameters =
dexGetParameterAnnotations(state->pDexFile, dir);
const DexMethodId* method =
dexGetMethodId(state->pDexFile, parameters[0].methodIdx);
return method->classIdx;
}
return kDexNoIndex;
}
/* Perform cross-item verification of annotations_directory_item. */
static void* crossVerifyAnnotationsDirectoryItem(const CheckState* state,
void* ptr) {
const DexAnnotationsDirectoryItem* item = (const DexAnnotationsDirectoryItem*) ptr;
u4 definingClass = findFirstAnnotationsDirectoryDefiner(state, item);
if (!dexDataMapVerify0Ok(state->pDataMap,
item->classAnnotationsOff, kDexTypeAnnotationSetItem)) {
return NULL;
}
const u1* addr = (const u1*) (item + 1);
if (item->fieldsSize != 0) {
addr = crossVerifyFieldAnnotations(state, item->fieldsSize, addr,
definingClass);
if (addr == NULL) {
return NULL;
}
}
if (item->methodsSize != 0) {
addr = crossVerifyMethodAnnotations(state, item->methodsSize, addr,
definingClass);
if (addr == NULL) {
return NULL;
}
}
if (item->parametersSize != 0) {
addr = crossVerifyParameterAnnotations(state, item->parametersSize,
addr, definingClass);
if (addr == NULL) {
return NULL;
}
}
return (void*) addr;
}
/* Perform byte-swapping and intra-item verification on type_list. */
static void* swapTypeList(const CheckState* state, void* ptr)
{
DexTypeList* pTypeList = (DexTypeList*) ptr;
DexTypeItem* pType;
u4 count;
CHECK_PTR_RANGE(pTypeList, pTypeList + 1);
SWAP_FIELD4(pTypeList->size);
count = pTypeList->size;
pType = pTypeList->list;
CHECK_LIST_SIZE(pType, count, sizeof(DexTypeItem));
while (count--) {
SWAP_INDEX2(pType->typeIdx, state->pHeader->typeIdsSize);
pType++;
}
return pType;
}
/* Perform byte-swapping and intra-item verification on
* annotation_set_ref_list. */
static void* swapAnnotationSetRefList(const CheckState* state, void* ptr) {
DexAnnotationSetRefList* list = (DexAnnotationSetRefList*) ptr;
DexAnnotationSetRefItem* item;
u4 count;
CHECK_PTR_RANGE(list, list + 1);
SWAP_FIELD4(list->size);
count = list->size;
item = list->list;
CHECK_LIST_SIZE(item, count, sizeof(DexAnnotationSetRefItem));
while (count--) {
SWAP_OFFSET4(item->annotationsOff);
item++;
}
return item;
}
/* Perform cross-item verification of annotation_set_ref_list. */
static void* crossVerifyAnnotationSetRefList(const CheckState* state,
void* ptr) {
const DexAnnotationSetRefList* list = (const DexAnnotationSetRefList*) ptr;
const DexAnnotationSetRefItem* item = list->list;
int count = list->size;
while (count--) {
if (!dexDataMapVerify0Ok(state->pDataMap,
item->annotationsOff, kDexTypeAnnotationSetItem)) {
return NULL;
}
item++;
}
return (void*) item;
}
/* Perform byte-swapping and intra-item verification on
* annotation_set_item. */
static void* swapAnnotationSetItem(const CheckState* state, void* ptr) {
DexAnnotationSetItem* set = (DexAnnotationSetItem*) ptr;
u4* item;
u4 count;
CHECK_PTR_RANGE(set, set + 1);
SWAP_FIELD4(set->size);
count = set->size;
item = set->entries;
CHECK_LIST_SIZE(item, count, sizeof(u4));
while (count--) {
SWAP_OFFSET4(*item);
item++;
}
return item;
}
/* Helper for crossVerifyAnnotationSetItem(), which extracts the type_idx
* out of an annotation_item. */
static u4 annotationItemTypeIdx(const DexAnnotationItem* item) {
const u1* data = item->annotation;
return readUnsignedLeb128(&data);
}
/* Perform cross-item verification of annotation_set_item. */
static void* crossVerifyAnnotationSetItem(const CheckState* state, void* ptr) {
const DexAnnotationSetItem* set = (const DexAnnotationSetItem*) ptr;
int count = set->size;
u4 lastIdx = 0;
bool first = true;
int i;
for (i = 0; i < count; i++) {
if (!dexDataMapVerify0Ok(state->pDataMap,
dexGetAnnotationOff(set, i), kDexTypeAnnotationItem)) {
return NULL;
}
const DexAnnotationItem* annotation =
dexGetAnnotationItem(state->pDexFile, set, i);
u4 idx = annotationItemTypeIdx(annotation);
if (first) {
first = false;
} else if (lastIdx >= idx) {
ALOGE("Out-of-order entry types: %#x then %#x",
lastIdx, idx);
return NULL;
}
lastIdx = idx;
}
return (void*) (set->entries + count);
}
/* Helper for verifyClassDataItem(), which checks a list of fields. */
static bool verifyFields(const CheckState* state, u4 size,
DexField* fields, bool expectStatic) {
u4 i;
for (i = 0; i < size; i++) {
DexField* field = &fields[i];
u4 accessFlags = field->accessFlags;
bool isStatic = (accessFlags & ACC_STATIC) != 0;
CHECK_INDEX(field->fieldIdx, state->pHeader->fieldIdsSize);
if (isStatic != expectStatic) {
ALOGE("Field in wrong list @ %d", i);
return false;
}
if ((accessFlags & ~ACC_FIELD_MASK) != 0) {
// The VM specification says that unknown flags should be ignored.
ALOGV("Bogus field access flags %x @ %d", accessFlags, i);
field->accessFlags &= ACC_FIELD_MASK;
}
}
return true;
}
/* Helper for verifyClassDataItem(), which checks a list of methods. */
static bool verifyMethods(const CheckState* state, u4 size,
DexMethod* methods, bool expectDirect) {
u4 i;
for (i = 0; i < size; i++) {
DexMethod* method = &methods[i];
CHECK_INDEX(method->methodIdx, state->pHeader->methodIdsSize);
u4 accessFlags = method->accessFlags;
bool isDirect =
(accessFlags & (ACC_STATIC | ACC_PRIVATE | ACC_CONSTRUCTOR)) != 0;
bool expectCode = (accessFlags & (ACC_NATIVE | ACC_ABSTRACT)) == 0;
bool isSynchronized = (accessFlags & ACC_SYNCHRONIZED) != 0;
bool allowSynchronized = (accessFlags & ACC_NATIVE) != 0;
if (isDirect != expectDirect) {
ALOGE("Method in wrong list @ %d", i);
return false;
}
if (isSynchronized && !allowSynchronized) {
ALOGE("Bogus method access flags (synchronization) %x @ %d", accessFlags, i);
return false;
}
if ((accessFlags & ~ACC_METHOD_MASK) != 0) {
// The VM specification says that unknown flags should be ignored.
ALOGV("Bogus method access flags %x @ %d", accessFlags, i);
method->accessFlags &= ACC_METHOD_MASK;
}
if (expectCode) {
if (method->codeOff == 0) {
ALOGE("Unexpected zero code_off for access_flags %x",
accessFlags);
return false;
}
} else if (method->codeOff != 0) {
ALOGE("Unexpected non-zero code_off %#x for access_flags %x",
method->codeOff, accessFlags);
return false;
}
}
return true;
}
/* Helper for verifyClassDataItem(), which does most of the work. */
static bool verifyClassDataItem0(const CheckState* state,
DexClassData* classData) {
bool okay;
okay = verifyFields(state, classData->header.staticFieldsSize,
classData->staticFields, true);
if (!okay) {
ALOGE("Trouble with static fields");
return false;
}
verifyFields(state, classData->header.instanceFieldsSize,
classData->instanceFields, false);
if (!okay) {
ALOGE("Trouble with instance fields");
return false;
}
okay = verifyMethods(state, classData->header.directMethodsSize,
classData->directMethods, true);
if (!okay) {
ALOGE("Trouble with direct methods");
return false;
}
okay = verifyMethods(state, classData->header.virtualMethodsSize,
classData->virtualMethods, false);
if (!okay) {
ALOGE("Trouble with virtual methods");
return false;
}
return true;
}
/* Perform intra-item verification on class_data_item. */
static void* intraVerifyClassDataItem(const CheckState* state, void* ptr) {
const u1* data = (const u1*) ptr;
DexClassData* classData = dexReadAndVerifyClassData(&data, state->fileEnd);
if (classData == NULL) {
ALOGE("Unable to parse class_data_item");
return NULL;
}
bool okay = verifyClassDataItem0(state, classData);
free(classData);
if (!okay) {
return NULL;
}
return (void*) data;
}
/* Helper for crossVerifyClassDefItem() and
* crossVerifyClassDataItem(), which finds the type_idx of the definer
* of the first item in the data. */
static u4 findFirstClassDataDefiner(const CheckState* state,
DexClassData* classData) {
if (classData->header.staticFieldsSize != 0) {
u4 fieldIdx = classData->staticFields[0].fieldIdx;
const DexFieldId* field = dexGetFieldId(state->pDexFile, fieldIdx);
return field->classIdx;
}
if (classData->header.instanceFieldsSize != 0) {
u4 fieldIdx = classData->instanceFields[0].fieldIdx;
const DexFieldId* field = dexGetFieldId(state->pDexFile, fieldIdx);
return field->classIdx;
}
if (classData->header.directMethodsSize != 0) {
u4 methodIdx = classData->directMethods[0].methodIdx;
const DexMethodId* meth = dexGetMethodId(state->pDexFile, methodIdx);
return meth->classIdx;
}
if (classData->header.virtualMethodsSize != 0) {
u4 methodIdx = classData->virtualMethods[0].methodIdx;
const DexMethodId* meth = dexGetMethodId(state->pDexFile, methodIdx);
return meth->classIdx;
}
return kDexNoIndex;
}
/* Perform cross-item verification of class_data_item. */
static void* crossVerifyClassDataItem(const CheckState* state, void* ptr) {
const u1* data = (const u1*) ptr;
DexClassData* classData = dexReadAndVerifyClassData(&data, state->fileEnd);
u4 definingClass = findFirstClassDataDefiner(state, classData);
bool okay = true;
u4 i;
for (i = classData->header.staticFieldsSize; okay && (i > 0); /*i*/) {
i--;
const DexField* field = &classData->staticFields[i];
okay = verifyFieldDefiner(state, definingClass, field->fieldIdx);
}
for (i = classData->header.instanceFieldsSize; okay && (i > 0); /*i*/) {
i--;
const DexField* field = &classData->instanceFields[i];
okay = verifyFieldDefiner(state, definingClass, field->fieldIdx);
}
for (i = classData->header.directMethodsSize; okay && (i > 0); /*i*/) {
i--;
const DexMethod* meth = &classData->directMethods[i];
okay = dexDataMapVerify0Ok(state->pDataMap, meth->codeOff,
kDexTypeCodeItem)
&& verifyMethodDefiner(state, definingClass, meth->methodIdx);
}
for (i = classData->header.virtualMethodsSize; okay && (i > 0); /*i*/) {
i--;
const DexMethod* meth = &classData->virtualMethods[i];
okay = dexDataMapVerify0Ok(state->pDataMap, meth->codeOff,
kDexTypeCodeItem)
&& verifyMethodDefiner(state, definingClass, meth->methodIdx);
}
free(classData);
if (!okay) {
return NULL;
}
return (void*) data;
}
/* Helper for swapCodeItem(), which fills an array with all the valid
* handlerOff values for catch handlers and also verifies the handler
* contents. */
static u4 setHandlerOffsAndVerify(const CheckState* state,
DexCode* code, u4 firstOffset, u4 handlersSize, u4* handlerOffs) {
const u1* fileEnd = state->fileEnd;
const u1* handlersBase = dexGetCatchHandlerData(code);
u4 offset = firstOffset;
bool okay = true;
u4 i;
for (i = 0; i < handlersSize; i++) {
const u1* ptr = handlersBase + offset;
int size = readAndVerifySignedLeb128(&ptr, fileEnd, &okay);
bool catchAll;
if (!okay) {
ALOGE("Bogus size");
return 0;
}
if ((size < -65536) || (size > 65536)) {
ALOGE("Invalid size: %d", size);
return 0;
}
if (size <= 0) {
catchAll = true;
size = -size;
} else {
catchAll = false;
}
handlerOffs[i] = offset;
while (size-- > 0) {
u4 typeIdx =
readAndVerifyUnsignedLeb128(&ptr, fileEnd, &okay);
if (!okay) {
ALOGE("Bogus type_idx");
return 0;
}
CHECK_INDEX(typeIdx, state->pHeader->typeIdsSize);
u4 addr = readAndVerifyUnsignedLeb128(&ptr, fileEnd, &okay);
if (!okay) {
ALOGE("Bogus addr");
return 0;
}
if (addr >= code->insnsSize) {
ALOGE("Invalid addr: %#x", addr);
return 0;
}
}
if (catchAll) {
u4 addr = readAndVerifyUnsignedLeb128(&ptr, fileEnd, &okay);
if (!okay) {
ALOGE("Bogus catch_all_addr");
return 0;
}
if (addr >= code->insnsSize) {
ALOGE("Invalid catch_all_addr: %#x", addr);
return 0;
}
}
offset = ptr - handlersBase;
}
return offset;
}
/* Helper for swapCodeItem(), which does all the try-catch related
* swapping and verification. */
static void* swapTriesAndCatches(const CheckState* state, DexCode* code) {
const u1* encodedHandlers = dexGetCatchHandlerData(code);
const u1* encodedPtr = encodedHandlers;
bool okay = true;
u4 handlersSize =
readAndVerifyUnsignedLeb128(&encodedPtr, state->fileEnd, &okay);
if (!okay) {
ALOGE("Bogus handlers_size");
return NULL;
}
if ((handlersSize == 0) || (handlersSize >= 65536)) {
ALOGE("Invalid handlers_size: %d", handlersSize);
return NULL;
}
u4 handlerOffs[handlersSize]; // list of valid handlerOff values
u4 endOffset = setHandlerOffsAndVerify(state, code,
encodedPtr - encodedHandlers,
handlersSize, handlerOffs);
if (endOffset == 0) {
return NULL;
}
DexTry* tries = (DexTry*) dexGetTries(code);
u4 count = code->triesSize;
u4 lastEnd = 0;
CHECK_LIST_SIZE(tries, count, sizeof(DexTry));
while (count--) {
u4 i;
SWAP_FIELD4(tries->startAddr);
SWAP_FIELD2(tries->insnCount);
SWAP_FIELD2(tries->handlerOff);
if (tries->startAddr < lastEnd) {
ALOGE("Out-of-order try");
return NULL;
}
if (tries->startAddr >= code->insnsSize) {
ALOGE("Invalid start_addr: %#x", tries->startAddr);
return NULL;
}
for (i = 0; i < handlersSize; i++) {
if (tries->handlerOff == handlerOffs[i]) {
break;
}
}
if (i == handlersSize) {
ALOGE("Bogus handler offset: %#x", tries->handlerOff);
return NULL;
}
lastEnd = tries->startAddr + tries->insnCount;
if (lastEnd > code->insnsSize) {
ALOGE("Invalid insn_count: %#x (end addr %#x)",
tries->insnCount, lastEnd);
return NULL;
}
tries++;
}
return (u1*) encodedHandlers + endOffset;
}
/* Perform byte-swapping and intra-item verification on code_item. */
static void* swapCodeItem(const CheckState* state, void* ptr) {
DexCode* item = (DexCode*) ptr;
u2* insns;
u4 count;
CHECK_PTR_RANGE(item, item + 1);
SWAP_FIELD2(item->registersSize);
SWAP_FIELD2(item->insSize);
SWAP_FIELD2(item->outsSize);
SWAP_FIELD2(item->triesSize);
SWAP_OFFSET4(item->debugInfoOff);
SWAP_FIELD4(item->insnsSize);
if (item->insSize > item->registersSize) {
ALOGE("insSize (%u) > registersSize (%u)", item->insSize,
item->registersSize);
return NULL;
}
if ((item->outsSize > 5) && (item->outsSize > item->registersSize)) {
/*
* It's okay for outsSize to be up to five, even if registersSize
* is smaller, since the short forms of method invocation allow
* repetition of a register multiple times within a single parameter
* list. Longer parameter lists, though, need to be represented
* in-order in the register file.
*/
ALOGE("outsSize (%u) > registersSize (%u)", item->outsSize,
item->registersSize);
return NULL;
}
count = item->insnsSize;
insns = item->insns;
CHECK_LIST_SIZE(insns, count, sizeof(u2));
while (count--) {
*insns = SWAP2(*insns);
insns++;
}
if (item->triesSize == 0) {
ptr = insns;
} else {
if ((((uintptr_t) insns) & 3) != 0) {
// Four-byte alignment for the tries. Verify the spacer is a 0.
if (*insns != 0) {
ALOGE("Non-zero padding: %#x", (u4) *insns);
return NULL;
}
}
ptr = swapTriesAndCatches(state, item);
}
return ptr;
}
/* Perform intra-item verification on string_data_item. */
static void* intraVerifyStringDataItem(const CheckState* state, void* ptr) {
const u1* fileEnd = state->fileEnd;
const u1* data = (const u1*) ptr;
bool okay = true;
u4 utf16Size = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
u4 i;
if (!okay) {
ALOGE("Bogus utf16_size");
return NULL;
}
for (i = 0; i < utf16Size; i++) {
if (data >= fileEnd) {
ALOGE("String data would go beyond end-of-file");
return NULL;
}
u1 byte1 = *(data++);
// Switch on the high four bits.
switch (byte1 >> 4) {
case 0x00: {
// Special case of bit pattern 0xxx.
if (byte1 == 0) {
ALOGE("String shorter than indicated utf16_size %#x",
utf16Size);
return NULL;
}
break;
}
case 0x01:
case 0x02:
case 0x03:
case 0x04:
case 0x05:
case 0x06:
case 0x07: {
// Bit pattern 0xxx. No need for any extra bytes or checks.
break;
}
case 0x08:
case 0x09:
case 0x0a:
case 0x0b:
case 0x0f: {
/*
* Bit pattern 10xx or 1111, which are illegal start bytes.
* Note: 1111 is valid for normal UTF-8, but not the
* modified UTF-8 used here.
*/
ALOGE("Illegal start byte %#x", byte1);
return NULL;
}
case 0x0e: {
// Bit pattern 1110, so there are two additional bytes.
u1 byte2 = *(data++);
if ((byte2 & 0xc0) != 0x80) {
ALOGE("Illegal continuation byte %#x", byte2);
return NULL;
}
u1 byte3 = *(data++);
if ((byte3 & 0xc0) != 0x80) {
ALOGE("Illegal continuation byte %#x", byte3);
return NULL;
}
u2 value = ((byte1 & 0x0f) << 12) | ((byte2 & 0x3f) << 6)
| (byte3 & 0x3f);
if (value < 0x800) {
ALOGE("Illegal representation for value %x", value);
return NULL;
}
break;
}
case 0x0c:
case 0x0d: {
// Bit pattern 110x, so there is one additional byte.
u1 byte2 = *(data++);
if ((byte2 & 0xc0) != 0x80) {
ALOGE("Illegal continuation byte %#x", byte2);
return NULL;
}
u2 value = ((byte1 & 0x1f) << 6) | (byte2 & 0x3f);
if ((value != 0) && (value < 0x80)) {
ALOGE("Illegal representation for value %x", value);
return NULL;
}
break;
}
}
}
if (*(data++) != '\0') {
ALOGE("String longer than indicated utf16_size %#x", utf16Size);
return NULL;
}
return (void*) data;
}
/* Perform intra-item verification on debug_info_item. */
static void* intraVerifyDebugInfoItem(const CheckState* state, void* ptr) {
const u1* fileEnd = state->fileEnd;
const u1* data = (const u1*) ptr;
bool okay = true;
u4 i;
readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) {
ALOGE("Bogus line_start");
return NULL;
}
u4 parametersSize =
readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) {
ALOGE("Bogus parameters_size");
return NULL;
}
if (parametersSize > 65536) {
ALOGE("Invalid parameters_size: %#x", parametersSize);
return NULL;
}
for (i = 0; i < parametersSize; i++) {
u4 parameterName =
readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) {
ALOGE("Bogus parameter_name");
return NULL;
}
if (parameterName != 0) {
parameterName--;
CHECK_INDEX(parameterName, state->pHeader->stringIdsSize);
}
}
bool done = false;
while (!done) {
u1 opcode = *(data++);
switch (opcode) {
case DBG_END_SEQUENCE: {
done = true;
break;
}
case DBG_ADVANCE_PC: {
readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
break;
}
case DBG_ADVANCE_LINE: {
readAndVerifySignedLeb128(&data, fileEnd, &okay);
break;
}
case DBG_START_LOCAL: {
u4 idx;
u4 regNum = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) break;
if (regNum >= 65536) {
okay = false;
break;
}
idx = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) break;
if (idx != 0) {
idx--;
CHECK_INDEX(idx, state->pHeader->stringIdsSize);
}
idx = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) break;
if (idx != 0) {
idx--;
CHECK_INDEX(idx, state->pHeader->stringIdsSize);
}
break;
}
case DBG_END_LOCAL:
case DBG_RESTART_LOCAL: {
u4 regNum = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) break;
if (regNum >= 65536) {
okay = false;
break;
}
break;
}
case DBG_START_LOCAL_EXTENDED: {
u4 idx;
u4 regNum = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) break;
if (regNum >= 65536) {
okay = false;
break;
}
idx = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) break;
if (idx != 0) {
idx--;
CHECK_INDEX(idx, state->pHeader->stringIdsSize);
}
idx = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) break;
if (idx != 0) {
idx--;
CHECK_INDEX(idx, state->pHeader->stringIdsSize);
}
idx = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) break;
if (idx != 0) {
idx--;
CHECK_INDEX(idx, state->pHeader->stringIdsSize);
}
break;
}
case DBG_SET_FILE: {
u4 idx = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) break;
if (idx != 0) {
idx--;
CHECK_INDEX(idx, state->pHeader->stringIdsSize);
}
break;
}
default: {
// No arguments to parse for anything else.
}
}
if (!okay) {
ALOGE("Bogus syntax for opcode %02x", opcode);
return NULL;
}
}
return (void*) data;
}
/* defined below */
static const u1* verifyEncodedValue(const CheckState* state, const u1* data,
bool crossVerify);
static const u1* verifyEncodedAnnotation(const CheckState* state,
const u1* data, bool crossVerify);
/* Helper for verifyEncodedValue(), which reads a 1- to 4- byte unsigned
* little endian value. */
static u4 readUnsignedLittleEndian(const CheckState* state, const u1** pData,
u4 size) {
const u1* data = *pData;
u4 result = 0;
u4 i;
CHECK_PTR_RANGE(data, data + size);
for (i = 0; i < size; i++) {
result |= ((u4) *(data++)) << (i * 8);
}
*pData = data;
return result;
}
/* Helper for *VerifyAnnotationItem() and *VerifyEncodedArrayItem(), which
* verifies an encoded_array. */
static const u1* verifyEncodedArray(const CheckState* state,
const u1* data, bool crossVerify) {
bool okay = true;
u4 size = readAndVerifyUnsignedLeb128(&data, state->fileEnd, &okay);
if (!okay) {
ALOGE("Bogus encoded_array size");
return NULL;
}
while (size--) {
data = verifyEncodedValue(state, data, crossVerify);
if (data == NULL) {
ALOGE("Bogus encoded_array value");
return NULL;
}
}
return data;
}
/* Helper for *VerifyAnnotationItem() and *VerifyEncodedArrayItem(), which
* verifies an encoded_value. */
static const u1* verifyEncodedValue(const CheckState* state,
const u1* data, bool crossVerify) {
CHECK_PTR_RANGE(data, data + 1);
u1 headerByte = *(data++);
u4 valueType = headerByte & kDexAnnotationValueTypeMask;
u4 valueArg = headerByte >> kDexAnnotationValueArgShift;
switch (valueType) {
case kDexAnnotationByte: {
if (valueArg != 0) {
ALOGE("Bogus byte size %#x", valueArg);
return NULL;
}
data++;
break;
}
case kDexAnnotationShort:
case kDexAnnotationChar: {
if (valueArg > 1) {
ALOGE("Bogus char/short size %#x", valueArg);
return NULL;
}
data += valueArg + 1;
break;
}
case kDexAnnotationInt:
case kDexAnnotationFloat: {
if (valueArg > 3) {
ALOGE("Bogus int/float size %#x", valueArg);
return NULL;
}
data += valueArg + 1;
break;
}
case kDexAnnotationLong:
case kDexAnnotationDouble: {
data += valueArg + 1;
break;
}
case kDexAnnotationString: {
if (valueArg > 3) {
ALOGE("Bogus string size %#x", valueArg);
return NULL;
}
u4 idx = readUnsignedLittleEndian(state, &data, valueArg + 1);
CHECK_INDEX(idx, state->pHeader->stringIdsSize);
break;
}
case kDexAnnotationType: {
if (valueArg > 3) {
ALOGE("Bogus type size %#x", valueArg);
return NULL;
}
u4 idx = readUnsignedLittleEndian(state, &data, valueArg + 1);
CHECK_INDEX(idx, state->pHeader->typeIdsSize);
break;
}
case kDexAnnotationField:
case kDexAnnotationEnum: {
if (valueArg > 3) {
ALOGE("Bogus field/enum size %#x", valueArg);
return NULL;
}
u4 idx = readUnsignedLittleEndian(state, &data, valueArg + 1);
CHECK_INDEX(idx, state->pHeader->fieldIdsSize);
break;
}
case kDexAnnotationMethod: {
if (valueArg > 3) {
ALOGE("Bogus method size %#x", valueArg);
return NULL;
}
u4 idx = readUnsignedLittleEndian(state, &data, valueArg + 1);
CHECK_INDEX(idx, state->pHeader->methodIdsSize);
break;
}
case kDexAnnotationArray: {
if (valueArg != 0) {
ALOGE("Bogus array value_arg %#x", valueArg);
return NULL;
}
data = verifyEncodedArray(state, data, crossVerify);
break;
}
case kDexAnnotationAnnotation: {
if (valueArg != 0) {
ALOGE("Bogus annotation value_arg %#x", valueArg);
return NULL;
}
data = verifyEncodedAnnotation(state, data, crossVerify);
break;
}
case kDexAnnotationNull: {
if (valueArg != 0) {
ALOGE("Bogus null value_arg %#x", valueArg);
return NULL;
}
// Nothing else to do for this type.
break;
}
case kDexAnnotationBoolean: {
if (valueArg > 1) {
ALOGE("Bogus boolean value_arg %#x", valueArg);
return NULL;
}
// Nothing else to do for this type.
break;
}
default: {
ALOGE("Bogus value_type %#x", valueType);
return NULL;
}
}
return data;
}
/* Helper for *VerifyAnnotationItem() and *VerifyEncodedArrayItem(), which
* verifies an encoded_annotation. */
static const u1* verifyEncodedAnnotation(const CheckState* state,
const u1* data, bool crossVerify) {
const u1* fileEnd = state->fileEnd;
bool okay = true;
u4 idx = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) {
ALOGE("Bogus encoded_annotation type_idx");
return NULL;
}
CHECK_INDEX(idx, state->pHeader->typeIdsSize);
if (crossVerify) {
const char* descriptor = dexStringByTypeIdx(state->pDexFile, idx);
if (!dexIsClassDescriptor(descriptor)) {
ALOGE("Bogus annotation type: '%s'", descriptor);
return NULL;
}
}
u4 size = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
u4 lastIdx = 0;
bool first = true;
if (!okay) {
ALOGE("Bogus encoded_annotation size");
return NULL;
}
while (size--) {
idx = readAndVerifyUnsignedLeb128(&data, fileEnd, &okay);
if (!okay) {
ALOGE("Bogus encoded_annotation name_idx");
return NULL;
}
CHECK_INDEX(idx, state->pHeader->stringIdsSize);
if (crossVerify) {
const char* name = dexStringById(state->pDexFile, idx);
if (!dexIsValidMemberName(name)) {
ALOGE("Bogus annotation member name: '%s'", name);
return NULL;
}
}
if (first) {
first = false;
} else if (lastIdx >= idx) {
ALOGE("Out-of-order encoded_annotation name_idx: %#x then %#x",
lastIdx, idx);
return NULL;
}
data = verifyEncodedValue(state, data, crossVerify);
lastIdx = idx;
if (data == NULL) {
return NULL;
}
}
return data;
}
/* Perform intra-item verification on encoded_array_item. */
static void* intraVerifyEncodedArrayItem(const CheckState* state, void* ptr) {
return (void*) verifyEncodedArray(state, (const u1*) ptr, false);
}
/* Perform intra-item verification on annotation_item. */
static void* intraVerifyAnnotationItem(const CheckState* state, void* ptr) {
const u1* data = (const u1*) ptr;
CHECK_PTR_RANGE(data, data + 1);
switch (*(data++)) {
case kDexVisibilityBuild:
case kDexVisibilityRuntime:
case kDexVisibilitySystem: {
break;
}
default: {
ALOGE("Bogus annotation visibility: %#x", *data);
return NULL;
}
}
return (void*) verifyEncodedAnnotation(state, data, false);
}
/* Perform cross-item verification on annotation_item. */
static void* crossVerifyAnnotationItem(const CheckState* state, void* ptr) {
const u1* data = (const u1*) ptr;
// Skip the visibility byte.
data++;
return (void*) verifyEncodedAnnotation(state, data, true);
}
/*
* Function to visit an individual top-level item type.
*/
typedef void* ItemVisitorFunction(const CheckState* state, void* ptr);
/*
* Iterate over all the items in a section, optionally updating the
* data map (done if mapType is passed as non-negative). The section
* must consist of concatenated items of the same type.
*/
static bool iterateSectionWithOptionalUpdate(CheckState* state,
u4 offset, u4 count, ItemVisitorFunction* func, u4 alignment,
u4* nextOffset, int mapType) {
u4 alignmentMask = alignment - 1;
u4 i;
state->previousItem = NULL;
for (i = 0; i < count; i++) {
u4 newOffset = (offset + alignmentMask) & ~alignmentMask;
u1* ptr = (u1*) filePointer(state, newOffset);
if (offset < newOffset) {
ptr = (u1*) filePointer(state, offset);
if (offset < newOffset) {
CHECK_OFFSET_RANGE(offset, newOffset);
while (offset < newOffset) {
if (*ptr != '\0') {
ALOGE("Non-zero padding 0x%02x @ %x", *ptr, offset);
return false;
}
ptr++;
offset++;
}
}
}
u1* newPtr = (u1*) func(state, ptr);
newOffset = fileOffset(state, newPtr);
if (newPtr == NULL) {
ALOGE("Trouble with item %d @ offset %#x", i, offset);
return false;
}
if (newOffset > state->fileLen) {
ALOGE("Item %d @ offset %#x ends out of bounds", i, offset);
return false;
}
if (mapType >= 0) {
dexDataMapAdd(state->pDataMap, offset, mapType);
}
state->previousItem = ptr;
offset = newOffset;
}
if (nextOffset != NULL) {
*nextOffset = offset;
}
return true;
}
/*
* Iterate over all the items in a section. The section must consist of
* concatenated items of the same type. This variant will not update the data
* map.
*/
static bool iterateSection(CheckState* state, u4 offset, u4 count,
ItemVisitorFunction* func, u4 alignment, u4* nextOffset) {
return iterateSectionWithOptionalUpdate(state, offset, count, func,
alignment, nextOffset, -1);
}
/*
* Like iterateSection(), but also check that the offset and count match
* a given pair of expected values.
*/
static bool checkBoundsAndIterateSection(CheckState* state,
u4 offset, u4 count, u4 expectedOffset, u4 expectedCount,
ItemVisitorFunction* func, u4 alignment, u4* nextOffset) {
if (offset != expectedOffset) {
ALOGE("Bogus offset for section: got %#x; expected %#x",
offset, expectedOffset);
return false;
}
if (count != expectedCount) {
ALOGE("Bogus size for section: got %#x; expected %#x",
count, expectedCount);
return false;
}
return iterateSection(state, offset, count, func, alignment, nextOffset);
}
/*
* Like iterateSection(), but also update the data section map and
* check that all the items fall within the data section.
*/
static bool iterateDataSection(CheckState* state, u4 offset, u4 count,
ItemVisitorFunction* func, u4 alignment, u4* nextOffset, int mapType) {
u4 dataStart = state->pHeader->dataOff;
u4 dataEnd = dataStart + state->pHeader->dataSize;
assert(nextOffset != NULL);
if ((offset < dataStart) || (offset >= dataEnd)) {
ALOGE("Bogus offset for data subsection: %#x", offset);
return false;
}
if (!iterateSectionWithOptionalUpdate(state, offset, count, func,
alignment, nextOffset, mapType)) {
return false;
}
if (*nextOffset > dataEnd) {
ALOGE("Out-of-bounds end of data subsection: %#x", *nextOffset);
return false;
}
return true;
}
/*
* Byte-swap all items in the given map except the header and the map
* itself, both of which should have already gotten swapped. This also
* does all possible intra-item verification, that is, verification
* that doesn't need to assume the sanctity of the contents of *other*
* items. The intra-item limitation is because at the time an item is
* asked to verify itself, it can't assume that the items it refers to
* have been byte-swapped and verified.
*/
static bool swapEverythingButHeaderAndMap(CheckState* state,
DexMapList* pMap) {
const DexMapItem* item = pMap->list;
u4 lastOffset = 0;
u4 count = pMap->size;
bool okay = true;
while (okay && count--) {
u4 sectionOffset = item->offset;
u4 sectionCount = item->size;
u2 type = item->type;
if (lastOffset < sectionOffset) {
CHECK_OFFSET_RANGE(lastOffset, sectionOffset);
const u1* ptr = (const u1*) filePointer(state, lastOffset);
while (lastOffset < sectionOffset) {
if (*ptr != '\0') {
ALOGE("Non-zero padding 0x%02x before section start @ %x",
*ptr, lastOffset);
okay = false;
break;
}
ptr++;
lastOffset++;
}
} else if (lastOffset > sectionOffset) {
ALOGE("Section overlap or out-of-order map: %x, %x",
lastOffset, sectionOffset);
okay = false;
}
if (!okay) {
break;
}
switch (type) {
case kDexTypeHeaderItem: {
/*
* The header got swapped very early on, but do some
* additional sanity checking here.
*/
okay = checkHeaderSection(state, sectionOffset, sectionCount,
&lastOffset);
break;
}
case kDexTypeStringIdItem: {
okay = checkBoundsAndIterateSection(state, sectionOffset,
sectionCount, state->pHeader->stringIdsOff,
state->pHeader->stringIdsSize, swapStringIdItem,
sizeof(u4), &lastOffset);
break;
}
case kDexTypeTypeIdItem: {
okay = checkBoundsAndIterateSection(state, sectionOffset,
sectionCount, state->pHeader->typeIdsOff,
state->pHeader->typeIdsSize, swapTypeIdItem,
sizeof(u4), &lastOffset);
break;
}
case kDexTypeProtoIdItem: {
okay = checkBoundsAndIterateSection(state, sectionOffset,
sectionCount, state->pHeader->protoIdsOff,
state->pHeader->protoIdsSize, swapProtoIdItem,
sizeof(u4), &lastOffset);
break;
}
case kDexTypeFieldIdItem: {
okay = checkBoundsAndIterateSection(state, sectionOffset,
sectionCount, state->pHeader->fieldIdsOff,
state->pHeader->fieldIdsSize, swapFieldIdItem,
sizeof(u4), &lastOffset);
break;
}
case kDexTypeMethodIdItem: {
okay = checkBoundsAndIterateSection(state, sectionOffset,
sectionCount, state->pHeader->methodIdsOff,
state->pHeader->methodIdsSize, swapMethodIdItem,
sizeof(u4), &lastOffset);
break;
}
case kDexTypeClassDefItem: {
okay = checkBoundsAndIterateSection(state, sectionOffset,
sectionCount, state->pHeader->classDefsOff,
state->pHeader->classDefsSize, swapClassDefItem,
sizeof(u4), &lastOffset);
break;
}
case kDexTypeMapList: {
/*
* The map section was swapped early on, but do some
* additional sanity checking here.
*/
okay = checkMapSection(state, sectionOffset, sectionCount,
&lastOffset);
break;
}
case kDexTypeTypeList: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
swapTypeList, sizeof(u4), &lastOffset, type);
break;
}
case kDexTypeAnnotationSetRefList: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
swapAnnotationSetRefList, sizeof(u4), &lastOffset,
type);
break;
}
case kDexTypeAnnotationSetItem: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
swapAnnotationSetItem, sizeof(u4), &lastOffset, type);
break;
}
case kDexTypeClassDataItem: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
intraVerifyClassDataItem, sizeof(u1), &lastOffset,
type);
break;
}
case kDexTypeCodeItem: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
swapCodeItem, sizeof(u4), &lastOffset, type);
break;
}
case kDexTypeStringDataItem: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
intraVerifyStringDataItem, sizeof(u1), &lastOffset,
type);
break;
}
case kDexTypeDebugInfoItem: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
intraVerifyDebugInfoItem, sizeof(u1), &lastOffset,
type);
break;
}
case kDexTypeAnnotationItem: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
intraVerifyAnnotationItem, sizeof(u1), &lastOffset,
type);
break;
}
case kDexTypeEncodedArrayItem: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
intraVerifyEncodedArrayItem, sizeof(u1), &lastOffset,
type);
break;
}
case kDexTypeAnnotationsDirectoryItem: {
okay = iterateDataSection(state, sectionOffset, sectionCount,
swapAnnotationsDirectoryItem, sizeof(u4), &lastOffset,
type);
break;
}
default: {
ALOGE("Unknown map item type %04x", type);
return false;
}
}
if (!okay) {
ALOGE("Swap of section type %04x failed", type);
}
item++;
}
return okay;
}
/*
* Perform cross-item verification on everything that needs it. This
* pass is only called after all items are byte-swapped and
* intra-verified (checked for internal consistency).
*/
static bool crossVerifyEverything(CheckState* state, DexMapList* pMap)
{
const DexMapItem* item = pMap->list;
u4 count = pMap->size;
bool okay = true;
while (okay && count--) {
u4 sectionOffset = item->offset;
u4 sectionCount = item->size;
switch (item->type) {
case kDexTypeHeaderItem:
case kDexTypeMapList:
case kDexTypeTypeList:
case kDexTypeCodeItem:
case kDexTypeStringDataItem:
case kDexTypeDebugInfoItem:
case kDexTypeAnnotationItem:
case kDexTypeEncodedArrayItem: {
// There is no need for cross-item verification for these.
break;
}
case kDexTypeStringIdItem: {
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyStringIdItem, sizeof(u4), NULL);
break;
}
case kDexTypeTypeIdItem: {
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyTypeIdItem, sizeof(u4), NULL);
break;
}
case kDexTypeProtoIdItem: {
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyProtoIdItem, sizeof(u4), NULL);
break;
}
case kDexTypeFieldIdItem: {
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyFieldIdItem, sizeof(u4), NULL);
break;
}
case kDexTypeMethodIdItem: {
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyMethodIdItem, sizeof(u4), NULL);
break;
}
case kDexTypeClassDefItem: {
// Allocate (on the stack) the "observed class_def" bits.
size_t arraySize = calcDefinedClassBitsSize(state);
u4 definedClassBits[arraySize];
memset(definedClassBits, 0, arraySize * sizeof(u4));
state->pDefinedClassBits = definedClassBits;
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyClassDefItem, sizeof(u4), NULL);
state->pDefinedClassBits = NULL;
break;
}
case kDexTypeAnnotationSetRefList: {
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyAnnotationSetRefList, sizeof(u4), NULL);
break;
}
case kDexTypeAnnotationSetItem: {
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyAnnotationSetItem, sizeof(u4), NULL);
break;
}
case kDexTypeClassDataItem: {
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyClassDataItem, sizeof(u1), NULL);
break;
}
case kDexTypeAnnotationsDirectoryItem: {
okay = iterateSection(state, sectionOffset, sectionCount,
crossVerifyAnnotationsDirectoryItem, sizeof(u4), NULL);
break;
}
default: {
ALOGE("Unknown map item type %04x", item->type);
return false;
}
}
if (!okay) {
ALOGE("Cross-item verify of section type %04x failed",
item->type);
}
item++;
}
return okay;
}
/* (documented in header file) */
bool dexHasValidMagic(const DexHeader* pHeader)
{
const u1* magic = pHeader->magic;
const u1* version = &magic[4];
if (memcmp(magic, DEX_MAGIC, 4) != 0) {
ALOGE("ERROR: unrecognized magic number (%02x %02x %02x %02x)",
magic[0], magic[1], magic[2], magic[3]);
return false;
}
if ((memcmp(version, DEX_MAGIC_VERS, 4) != 0) &&
(memcmp(version, DEX_MAGIC_VERS_API_13, 4) != 0)) {
/*
* Magic was correct, but this is an unsupported older or
* newer format variant.
*/
ALOGE("ERROR: unsupported dex version (%02x %02x %02x %02x)",
version[0], version[1], version[2], version[3]);
return false;
}
return true;
}
/*
* Fix the byte ordering of all fields in the DEX file, and do
* structural verification. This is only required for code that opens
* "raw" DEX files, such as the DEX optimizer.
*
* Returns 0 on success, nonzero on failure.
*/
int dexSwapAndVerify(u1* addr, int len)
{
DexHeader* pHeader;
CheckState state;
bool okay = true;
memset(&state, 0, sizeof(state));
ALOGV("+++ swapping and verifying");
/*
* Note: The caller must have verified that "len" is at least as
* large as a dex file header.
*/
pHeader = (DexHeader*) addr;
if (!dexHasValidMagic(pHeader)) {
okay = false;
}
if (okay) {
int expectedLen = (int) SWAP4(pHeader->fileSize);
if (len < expectedLen) {
ALOGE("ERROR: Bad length: expected %d, got %d", expectedLen, len);
okay = false;
} else if (len != expectedLen) {
ALOGW("WARNING: Odd length: expected %d, got %d", expectedLen,
len);
// keep going
}
}
if (okay) {
/*
* Compute the adler32 checksum and compare it to what's stored in
* the file. This isn't free, but chances are good that we just
* unpacked this from a jar file and have all of the pages sitting
* in memory, so it's pretty quick.
*
* This might be a big-endian system, so we need to do this before
* we byte-swap the header.
*/
uLong adler = adler32(0L, Z_NULL, 0);
const int nonSum = sizeof(pHeader->magic) + sizeof(pHeader->checksum);
u4 storedFileSize = SWAP4(pHeader->fileSize);
u4 expectedChecksum = SWAP4(pHeader->checksum);
adler = adler32(adler, ((const u1*) pHeader) + nonSum,
storedFileSize - nonSum);
if (adler != expectedChecksum) {
ALOGE("ERROR: bad checksum (%08lx, expected %08x)",
adler, expectedChecksum);
okay = false;
}
}
if (okay) {
state.fileStart = addr;
state.fileEnd = addr + len;
state.fileLen = len;
state.pDexFile = NULL;
state.pDataMap = NULL;
state.pDefinedClassBits = NULL;
state.previousItem = NULL;
/*
* Swap the header and check the contents.
*/
okay = swapDexHeader(&state, pHeader);
}
if (okay) {
state.pHeader = pHeader;
if (pHeader->headerSize < sizeof(DexHeader)) {
ALOGE("ERROR: Small header size %d, struct %d",
pHeader->headerSize, (int) sizeof(DexHeader));
okay = false;
} else if (pHeader->headerSize > sizeof(DexHeader)) {
ALOGW("WARNING: Large header size %d, struct %d",
pHeader->headerSize, (int) sizeof(DexHeader));
// keep going?
}
}
if (okay) {
/*
* Look for the map. Swap it and then use it to find and swap
* everything else.
*/
if (pHeader->mapOff != 0) {
DexFile dexFile;
DexMapList* pDexMap = (DexMapList*) (addr + pHeader->mapOff);
okay = okay && swapMap(&state, pDexMap);
okay = okay && swapEverythingButHeaderAndMap(&state, pDexMap);
dexFileSetupBasicPointers(&dexFile, addr);
state.pDexFile = &dexFile;
okay = okay && crossVerifyEverything(&state, pDexMap);
} else {
ALOGE("ERROR: No map found; impossible to byte-swap and verify");
okay = false;
}
}
if (!okay) {
ALOGE("ERROR: Byte swap + verify failed");
}
if (state.pDataMap != NULL) {
dexDataMapFree(state.pDataMap);
}
return !okay; // 0 == success
}
/*
* Detect the file type of the given memory buffer via magic number.
* Call dexSwapAndVerify() on an unoptimized DEX file, do nothing
* but return successfully on an optimized DEX file, and report an
* error for all other cases.
*
* Returns 0 on success, nonzero on failure.
*/
int dexSwapAndVerifyIfNecessary(u1* addr, int len)
{
if (memcmp(addr, DEX_OPT_MAGIC, 4) == 0) {
// It is an optimized dex file.
return 0;
}
if (memcmp(addr, DEX_MAGIC, 4) == 0) {
// It is an unoptimized dex file.
return dexSwapAndVerify(addr, len);
}
ALOGE("ERROR: Bad magic number (0x%02x %02x %02x %02x)",
addr[0], addr[1], addr[2], addr[3]);
return 1;
}