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author | srs5694 <srs5694@users.sourceforge.net> | 2011-09-18 21:12:28 -0400 |
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committer | srs5694 <srs5694@users.sourceforge.net> | 2011-09-18 21:12:28 -0400 |
commit | d1b11e8305621d73ff675af940e7f1f28b639b0d (patch) | |
tree | d7c328769b3015c7737bd07928960d6b92fd4cff /gpt.cc | |
parent | f502e52912a28bc57d4a88c6f8f2f5efc6da602c (diff) | |
download | sgdisk-d1b11e8305621d73ff675af940e7f1f28b639b0d.tar.gz |
Fixed bug in reading GPTs with encoded header sizes other than 92 bytes.
Diffstat (limited to 'gpt.cc')
-rw-r--r-- | gpt.cc | 94 |
1 files changed, 64 insertions, 30 deletions
@@ -27,7 +27,6 @@ #include "parttypes.h" #include "attributes.h" #include "diskio.h" -//#include "partnotes.h" using namespace std; @@ -65,6 +64,8 @@ GPTData::GPTData(void) { mainHeader.numParts = 0; numParts = 0; SetGPTSize(NUM_GPT_ENTRIES); + // Initialize CRC functions... + chksum_crc32gentab(); } // GPTData default constructor // The following constructor loads GPT data from a device file @@ -86,6 +87,8 @@ GPTData::GPTData(string filename) { whichWasUsed = use_new; mainHeader.numParts = 0; numParts = 0; + // Initialize CRC functions... + chksum_crc32gentab(); if (!LoadPartitions(filename)) exit(2); } // GPTData(string filename) constructor @@ -129,7 +132,8 @@ GPTData & GPTData::operator=(const GPTData & orig) { } // if for (i = 0; i < numParts; i++) { partitions[i] = orig.partitions[i]; - } + } // for + return *this; } // GPTData::operator=() @@ -353,8 +357,8 @@ int GPTData::CheckGPTSize(void) { // Check the validity of the GPT header. Returns 1 if the main header // is valid, 2 if the backup header is valid, 3 if both are valid, and -// 0 if neither is valid. Note that this function just checks the GPT -// signature and revision numbers, not CRCs or other data. +// 0 if neither is valid. Note that this function checks the GPT signature, +// revision value, and CRCs in both headers. int GPTData::CheckHeaderValidity(void) { int valid = 3; @@ -363,7 +367,7 @@ int GPTData::CheckHeaderValidity(void) { // Note: failed GPT signature checks produce no error message because // a message is displayed in the ReversePartitionBytes() function - if (mainHeader.signature != GPT_SIGNATURE) { + if ((mainHeader.signature != GPT_SIGNATURE) || (!CheckHeaderCRC(&mainHeader, 1))) { valid -= 1; } else if ((mainHeader.revision != 0x00010000) && valid) { valid -= 1; @@ -374,7 +378,7 @@ int GPTData::CheckHeaderValidity(void) { cout << UINT32_C(0x00010000) << dec << "\n"; } // if/else/if - if (secondHeader.signature != GPT_SIGNATURE) { + if ((secondHeader.signature != GPT_SIGNATURE) || (!CheckHeaderCRC(&secondHeader))) { valid -= 2; } else if ((secondHeader.revision != 0x00010000) && valid) { valid -= 2; @@ -396,27 +400,50 @@ int GPTData::CheckHeaderValidity(void) { } // GPTData::CheckHeaderValidity() // Check the header CRC to see if it's OK... -// Note: Must be called with header in LITTLE-ENDIAN -// (x86, x86-64, etc.) byte order. -int GPTData::CheckHeaderCRC(struct GPTHeader* header) { +// Note: Must be called with header in platform-ordered byte order. +// Returns 1 if header's computed CRC matches the stored value, 0 if the +// computed and stored values don't match +int GPTData::CheckHeaderCRC(struct GPTHeader* header, int warn) { uint32_t oldCRC, newCRC, hSize; + uint8_t *temp; // Back up old header CRC and then blank it, since it must be 0 for // computation to be valid oldCRC = header->headerCRC; header->headerCRC = UINT32_C(0); + hSize = header->headerSize; - // If big-endian system, reverse byte order - if (IsLittleEndian() == 0) { - ReverseBytes(&oldCRC, 4); - } // if + if (IsLittleEndian() == 0) + ReverseHeaderBytes(header); - // Initialize CRC functions... - chksum_crc32gentab(); + if ((hSize > blockSize) || (hSize < HEADER_SIZE)) { + if (warn) { + cerr << "\aWarning! Header size is specified as " << hSize << ", which is invalid.\n"; + cerr << "Setting the header size for CRC computation to " << HEADER_SIZE << "\n"; + } // if + hSize = HEADER_SIZE; + } else if ((hSize > sizeof(GPTHeader)) && warn) { + cout << "\aCaution! Header size for CRC check is " << hSize << ", which is greater than " << sizeof(GPTHeader) << ".\n"; + cout << "If stray data exists after the header on the header sector, it will be ignored,\n" + << "which may result in a CRC false alarm.\n"; + } // if/elseif + temp = new uint8_t[hSize]; + if (temp != NULL) { + memset(temp, 0, hSize); + if (hSize < sizeof(GPTHeader)) + memcpy(temp, header, hSize); + else + memcpy(temp, header, sizeof(GPTHeader)); - // Compute CRC, restore original, and return result of comparison - newCRC = chksum_crc32((unsigned char*) header, HEADER_SIZE); + newCRC = chksum_crc32((unsigned char*) temp, hSize); + delete[] temp; + } else { + cerr << "Could not allocate memory in GPTData::CheckHeaderCRC()! Aborting!\n"; + exit(1); + } + if (IsLittleEndian() == 0) + ReverseHeaderBytes(header); header->headerCRC = oldCRC; return (oldCRC == newCRC); } // GPTData::CheckHeaderCRC() @@ -428,11 +455,12 @@ void GPTData::RecomputeCRCs(void) { uint32_t crc, hSize; int littleEndian = 1; - // Initialize CRC functions... - chksum_crc32gentab(); - - // Save some key data from header before reversing byte order.... - hSize = mainHeader.headerSize; + // If the header size is bigger than the GPT header data structure, reset it; + // otherwise, set both header sizes to whatever the main one is.... + if (mainHeader.headerSize > sizeof(GPTHeader)) + hSize = secondHeader.headerSize = mainHeader.headerSize = HEADER_SIZE; + else + hSize = secondHeader.headerSize = mainHeader.headerSize; if ((littleEndian = IsLittleEndian()) == 0) { ReversePartitionBytes(); @@ -449,11 +477,10 @@ void GPTData::RecomputeCRCs(void) { ReverseBytes(&secondHeader.partitionEntriesCRC, 4); } // if - // Zero out GPT tables' own CRCs (required for correct computation) + // Zero out GPT headers' own CRCs (required for correct computation) mainHeader.headerCRC = 0; secondHeader.headerCRC = 0; - // Compute & store CRCs of main & secondary headers... crc = chksum_crc32((unsigned char*) &mainHeader, hSize); if (littleEndian == 0) ReverseBytes(&crc, 4); @@ -463,7 +490,7 @@ void GPTData::RecomputeCRCs(void) { ReverseBytes(&crc, 4); secondHeader.headerCRC = crc; - if ((littleEndian = IsLittleEndian()) == 0) { + if (littleEndian == 0) { ReverseHeaderBytes(&mainHeader); ReverseHeaderBytes(&secondHeader); ReversePartitionBytes(); @@ -524,9 +551,9 @@ int GPTData::FindHybridMismatches(void) { if ((protectiveMBR.GetType(i) != 0xEE) && (protectiveMBR.GetType(i) != 0x00)) { j = 0; found = 0; + mbrFirst = (uint64_t) protectiveMBR.GetFirstSector(i); + mbrLast = mbrFirst + (uint64_t) protectiveMBR.GetLength(i) - UINT64_C(1); do { - mbrFirst = (uint64_t) protectiveMBR.GetFirstSector(i); - mbrLast = mbrFirst + (uint64_t) protectiveMBR.GetLength(i) - UINT64_C(1); if ((partitions[j].GetFirstLBA() == mbrFirst) && (partitions[j].GetLastLBA() == mbrLast)) found = 1; @@ -551,6 +578,7 @@ int GPTData::FindHybridMismatches(void) { // Find overlapping partitions and warn user about them. Returns number of // overlapping partitions. +// Returns number of overlapping segments found. int GPTData::FindOverlaps(void) { int problems = 0; uint32_t i, j; @@ -574,6 +602,7 @@ int GPTData::FindOverlaps(void) { // big for the disk. (The latter should duplicate detection of overlaps // with GPT backup data structures, but better to err on the side of // redundant tests than to miss something....) +// Returns number of problems found. int GPTData::FindInsanePartitions(void) { uint32_t i; int problems = 0; @@ -841,12 +870,12 @@ int GPTData::LoadHeader(struct GPTHeader *header, DiskIO & disk, uint64_t sector cerr << "Warning! Read error " << errno << "; strange behavior now likely!\n"; allOK = 0; } // if - *crcOk = CheckHeaderCRC(&tempHeader); // Reverse byte order, if necessary if (IsLittleEndian() == 0) { ReverseHeaderBytes(&tempHeader); } // if + *crcOk = CheckHeaderCRC(&tempHeader); if (allOK && (numParts != tempHeader.numParts) && *crcOk) { allOK = SetGPTSize(tempHeader.numParts); @@ -904,6 +933,7 @@ int GPTData::LoadPartitionTable(const struct GPTHeader & header, DiskIO & disk, int GPTData::CheckTable(struct GPTHeader *header) { uint32_t sizeOfParts, newCRC; GPTPart *partsToCheck; + GPTHeader *otherHeader; int allOK = 0; // Load partition table into temporary storage to check @@ -919,9 +949,13 @@ int GPTData::CheckTable(struct GPTHeader *header) { if (myDisk.Read(partsToCheck, sizeOfParts) != (int) sizeOfParts) { cerr << "Warning! Error " << errno << " reading partition table for CRC check!\n"; } else { - newCRC = chksum_crc32((unsigned char*) partsToCheck, sizeOfParts); + newCRC = chksum_crc32((unsigned char*) partsToCheck, sizeOfParts); allOK = (newCRC == header->partitionEntriesCRC); - if (memcmp(partitions, partsToCheck, sizeOfParts) != 0) { + if (header == &mainHeader) + otherHeader = &secondHeader; + else + otherHeader = &mainHeader; + if (newCRC != otherHeader->partitionEntriesCRC) { cerr << "Warning! Main and backup partition tables differ! Use the 'c' and 'e' options\n" << "on the recovery & transformation menu to examine the two tables.\n\n"; allOK = 0; |