1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 /* 18 * Functions to parse and manipulate the additional data tables added 19 * to optimized .dex files. 20 */ 21 22 #include <zlib.h> 23 24 #include "DexOptData.h" 25 26 /* 27 * Check to see if a given data pointer is a valid double-word-aligned 28 * pointer into the given memory range (from start inclusive to end 29 * exclusive). Returns true if valid. 30 */ 31 static bool isValidPointer(const void* ptr, const void* start, const void* end) 32 { 33 return (ptr >= start) && (ptr < end) && (((u4) ptr & 7) == 0); 34 } 35 36 /* (documented in header file) */ 37 u4 dexComputeOptChecksum(const DexOptHeader* pOptHeader) 38 { 39 const u1* start = (const u1*) pOptHeader + pOptHeader->depsOffset; 40 const u1* end = (const u1*) pOptHeader + 41 pOptHeader->optOffset + pOptHeader->optLength; 42 43 uLong adler = adler32(0L, Z_NULL, 0); 44 45 return (u4) adler32(adler, start, end - start); 46 } 47 48 /* (documented in header file) */ 49 bool dexParseOptData(const u1* data, size_t length, DexFile* pDexFile) 50 { 51 const void* pOptStart = data + pDexFile->pOptHeader->optOffset; 52 const void* pOptEnd = data + length; 53 const u4* pOpt = (const u4*) pOptStart; 54 u4 optLength = (const u1*) pOptEnd - (const u1*) pOptStart; 55 56 /* 57 * Make sure the opt data start is in range and aligned. This may 58 * seem like a superfluous check, but (a) if the file got 59 * truncated, it might turn out that pOpt >= pOptEnd; and (b) 60 * if the opt data header got corrupted, pOpt might not be 61 * properly aligned. This test will catch both of these cases. 62 */ 63 if (!isValidPointer(pOpt, pOptStart, pOptEnd)) { 64 LOGE("Bogus opt data start pointer"); 65 return false; 66 } 67 68 /* Make sure that the opt data length is a whole number of words. */ 69 if ((optLength & 3) != 0) { 70 LOGE("Unaligned opt data area end"); 71 return false; 72 } 73 74 /* 75 * Make sure that the opt data area is large enough to have at least 76 * one chunk header. 77 */ 78 if (optLength < 8) { 79 LOGE("Undersized opt data area (%u)", optLength); 80 return false; 81 } 82 83 /* Process chunks until we see the end marker. */ 84 while (*pOpt != kDexChunkEnd) { 85 if (!isValidPointer(pOpt + 2, pOptStart, pOptEnd)) { 86 LOGE("Bogus opt data content pointer at offset %u", 87 ((const u1*) pOpt) - data); 88 return false; 89 } 90 91 u4 size = *(pOpt + 1); 92 const u1* pOptData = (const u1*) (pOpt + 2); 93 94 /* 95 * The rounded size is 64-bit aligned and includes +8 for the 96 * type/size header (which was extracted immediately above). 97 */ 98 u4 roundedSize = (size + 8 + 7) & ~7; 99 const u4* pNextOpt = pOpt + (roundedSize / sizeof(u4)); 100 101 if (!isValidPointer(pNextOpt, pOptStart, pOptEnd)) { 102 LOGE("Opt data area problem for chunk of size %u at offset %u", 103 size, ((const u1*) pOpt) - data); 104 return false; 105 } 106 107 switch (*pOpt) { 108 case kDexChunkClassLookup: 109 pDexFile->pClassLookup = (const DexClassLookup*) pOptData; 110 break; 111 case kDexChunkRegisterMaps: 112 LOGV("+++ found register maps, size=%u", size); 113 pDexFile->pRegisterMapPool = pOptData; 114 break; 115 default: 116 LOGI("Unknown chunk 0x%08x (%c%c%c%c), size=%d in opt data area", 117 *pOpt, 118 (char) ((*pOpt) >> 24), (char) ((*pOpt) >> 16), 119 (char) ((*pOpt) >> 8), (char) (*pOpt), 120 size); 121 break; 122 } 123 124 pOpt = pNextOpt; 125 } 126 127 return true; 128 } 129