Fixed bug in reading GPTs with encoded header sizes other than 92 bytes.
diff --git a/gpt.cc b/gpt.cc
index 25ca53a..767f943 100644
--- a/gpt.cc
+++ b/gpt.cc
@@ -27,7 +27,6 @@
#include "parttypes.h"
#include "attributes.h"
#include "diskio.h"
-//#include "partnotes.h"
using namespace std;
@@ -65,6 +64,8 @@
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 @@
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 @@
} // if
for (i = 0; i < numParts; i++) {
partitions[i] = orig.partitions[i];
- }
+ } // for
+
return *this;
} // GPTData::operator=()
@@ -353,8 +357,8 @@
// 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 @@
// 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 @@
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 @@
} // 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 @@
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 @@
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 @@
ReverseBytes(&crc, 4);
secondHeader.headerCRC = crc;
- if ((littleEndian = IsLittleEndian()) == 0) {
+ if (littleEndian == 0) {
ReverseHeaderBytes(&mainHeader);
ReverseHeaderBytes(&secondHeader);
ReversePartitionBytes();
@@ -524,9 +551,9 @@
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 @@
// 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 @@
// 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 @@
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::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 @@
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;