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DexSwapVerify.c
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DexSwapVerify.c
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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.
*/
/*
* Byte-swapping and verification of dex files.
*/
#include "DexFile.h"
#include "DexClass.h"
#include "DexDataMap.h"
#include "DexProto.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.
*/
typedef 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
const void* previousItem; // set during section iteration
} CheckState;
/*
* 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)) {
LOGW("Bad offset range for %s: 0x%x..0x%x\n", 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 = filePointer(state, (_start)); \
const u1* _endPtr = 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)) { \
LOGW("Bad index: %s(%u) > %s(%u)\n", \
#_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)) { \
LOGW("Bad index: %s(%u) > %s(%u)\n", \
#_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;
}
/*
* 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) {
LOGE("Unexpected endian_tag: 0x%x\n", 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) {
LOGE("Multiple header items\n");
return false;
}
if (sectionOffset != 0) {
LOGE("Header at 0x%x; not at start of file\n", sectionOffset);
return false;
}
const DexHeader* pHeader = 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: {
LOGE("Unknown map item type %04x\n", 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) {
LOGE("Out-of-order map item: 0x%x then 0x%x\n",
lastOffset, item->offset);
return false;
}
if (item->offset >= state->pHeader->fileSize) {
LOGE("Map item after end of file: %x, size 0x%x\n",
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) {
LOGE("Unrealistically many items in the data section: "
"at least %d\n", dataItemCount + icount);
return false;
}
dataItemsLeft -= icount;
dataItemCount += icount;
}
u4 bit = mapTypeToBitMask(item->type);
if (bit == 0) {
return false;
}
if ((usedBits & bit) != 0) {
LOGE("Duplicate map section of type 0x%x\n", item->type);
return false;
}
usedBits |= bit;
lastOffset = item->offset;
item++;
}
if ((usedBits & mapTypeToBitMask(kDexTypeHeaderItem)) == 0) {
LOGE("Map is missing header entry\n");
return false;
}
if ((usedBits & mapTypeToBitMask(kDexTypeMapList)) == 0) {
LOGE("Map is missing map_list entry\n");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeStringIdItem)) == 0)
&& ((state->pHeader->stringIdsOff != 0)
|| (state->pHeader->stringIdsSize != 0))) {
LOGE("Map is missing string_ids entry\n");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeTypeIdItem)) == 0)
&& ((state->pHeader->typeIdsOff != 0)
|| (state->pHeader->typeIdsSize != 0))) {
LOGE("Map is missing type_ids entry\n");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeProtoIdItem)) == 0)
&& ((state->pHeader->protoIdsOff != 0)
|| (state->pHeader->protoIdsSize != 0))) {
LOGE("Map is missing proto_ids entry\n");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeFieldIdItem)) == 0)
&& ((state->pHeader->fieldIdsOff != 0)
|| (state->pHeader->fieldIdsSize != 0))) {
LOGE("Map is missing field_ids entry\n");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeMethodIdItem)) == 0)
&& ((state->pHeader->methodIdsOff != 0)
|| (state->pHeader->methodIdsSize != 0))) {
LOGE("Map is missing method_ids entry\n");
return false;
}
if (((usedBits & mapTypeToBitMask(kDexTypeClassDefItem)) == 0)
&& ((state->pHeader->classDefsOff != 0)
|| (state->pHeader->classDefsSize != 0))) {
LOGE("Map is missing class_defs entry\n");
return false;
}
state->pDataMap = dexDataMapAlloc(dataItemCount);
if (state->pDataMap == NULL) {
LOGE("Unable to allocate data map (size 0x%x)\n", 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) {
LOGE("Multiple map list items");
return false;
}
if (sectionOffset != state->pHeader->mapOff) {
LOGE("Map not at header-defined offset: 0x%x, expected 0x%x\n",
sectionOffset, state->pHeader->mapOff);
return false;
}
const DexMapList* pMap = 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 = 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 = ptr;
if (!dexDataMapVerify(state->pDataMap,
item->stringDataOff, kDexTypeStringDataItem)) {
return NULL;
}
const DexStringId* item0 = 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) {
LOGE("Out-of-order string_ids: '%s' then '%s'\n", 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 = 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 = ptr;
const char* descriptor =
dexStringById(state->pDexFile, item->descriptorIdx);
if (!dexIsValidTypeDescriptor(descriptor)) {
LOGE("Invalid type descriptor: '%s'\n", descriptor);
return NULL;
}
const DexTypeId* item0 = state->previousItem;
if (item0 != NULL) {
// Check ordering. This relies on string_ids being in order.
if (item0->descriptorIdx >= item->descriptorIdx) {
LOGE("Out-of-order type_ids: 0x%x then 0x%x\n",
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 = 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) {
LOGE("Invalid use of void\n");
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')) {
LOGE("Shorty vs. primitive type mismatch: '%c', '%s'\n",
shorty, descriptor);
return false;
}
break;
}
case 'L': {
if ((descriptor[0] != 'L') && (descriptor[0] != '[')) {
LOGE("Shorty vs. type mismatch: '%c', '%s'\n",
shorty, descriptor);
return false;
}
break;
}
default: {
LOGE("Bogus shorty: '%c'\n", shorty);
return false;
}
}
return true;
}
/* Perform cross-item verification of proto_id_item. */
static void* crossVerifyProtoIdItem(const CheckState* state, void* ptr) {
const DexProtoId* item = 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') {
LOGE("Shorty is too short\n");
return NULL;
}
if (!shortyDescMatch(*shorty, desc, false)) {
return NULL;
}
shorty++;
}
if (*shorty != '\0') {
LOGE("Shorty is too long\n");
return NULL;
}
const DexProtoId* item0 = state->previousItem;
if (item0 != NULL) {
// Check ordering. This relies on type_ids being in order.
if (item0->returnTypeIdx > item->returnTypeIdx) {
LOGE("Out-of-order proto_id return types\n");
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) {
LOGE("Out-of-order proto_id arguments\n");
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 = 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 = ptr;
const char* s;
s = dexStringByTypeIdx(state->pDexFile, item->classIdx);
if (!dexIsClassDescriptor(s)) {
LOGE("Invalid descriptor for class_idx: '%s'\n", s);
return NULL;
}
s = dexStringByTypeIdx(state->pDexFile, item->typeIdx);
if (!dexIsFieldDescriptor(s)) {
LOGE("Invalid descriptor for type_idx: '%s'\n", s);
return NULL;
}
s = dexStringById(state->pDexFile, item->nameIdx);
if (!dexIsValidMemberName(s)) {
LOGE("Invalid name: '%s'\n", s);
return NULL;
}
const DexFieldId* item0 = 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) {
LOGE("Out-of-order field_ids\n");
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 = 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 = ptr;
const char* s;
s = dexStringByTypeIdx(state->pDexFile, item->classIdx);
if (!dexIsReferenceDescriptor(s)) {
LOGE("Invalid descriptor for class_idx: '%s'\n", s);
return NULL;
}
s = dexStringById(state->pDexFile, item->nameIdx);
if (!dexIsValidMemberName(s)) {
LOGE("Invalid name: '%s'\n", s);
return NULL;
}
const DexMethodId* item0 = 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) {
LOGE("Out-of-order method_ids\n");
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 = 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);
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 = 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 = 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 = ptr;
const char* descriptor =
dexStringByTypeIdx(state->pDexFile, item->classIdx);
if (!dexIsClassDescriptor(descriptor)) {
LOGE("Invalid class: '%s'\n", 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)) {
LOGE("Invalid superclass: '%s'\n", 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)) {
LOGE("Invalid interface: '%s'\n", 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) {
LOGE("Duplicate interface: '%s'\n",
dexStringByTypeIdx(state->pDexFile, idx1));
return NULL;