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GP-4575: Fixed some issues in the MzLoader (Closes #5970)

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This commit is contained in:
Ryan Kurtz 2024-05-02 06:41:51 -04:00
parent 146f6d2a29
commit 2bf16b0ca6
1 changed files with 21 additions and 9 deletions
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30
Ghidra/Features/Base/src/main/java/ghidra/app/util/opinion/MzLoader.java
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@ -131,9 +131,10 @@ public class MzLoader extends AbstractLibrarySupportLoader {
* @param address The {@link SegmentedAddress} of the relocation
* @param fileOffset The file offset of the relocation
* @param segment The fixed-up segment after the relocation is applied
* @param valid True if the relocation is valid; otherwise, false
*/
private record RelocationFixup(MzRelocation relocation, SegmentedAddress address,
int fileOffset, int segment) {}
int fileOffset, int segment, boolean valid) {}
private void markupHeaders(Program program, FileBytes fileBytes, MzExecutable mz,
MessageLog log, TaskMonitor monitor) {
@ -181,7 +182,9 @@ public class MzLoader extends AbstractLibrarySupportLoader {
// Use relocations to discover what segments are in use.
// We also know about our desired load module segment, so add that too.
Set<SegmentedAddress> knownSegments = new TreeSet<>();
relocationFixups.forEach(rf -> knownSegments.add(space.getAddress(rf.segment, 0)));
relocationFixups.stream()
.filter(RelocationFixup::valid)
.forEach(rf -> knownSegments.add(space.getAddress(rf.segment, 0)));
knownSegments.add(space.getAddress(INITIAL_SEGMENT_VAL, 0));
if (header.e_cs() > 0) {
knownSegments.add(space.getAddress((INITIAL_SEGMENT_VAL + header.e_cs()) & 0xffff, 0));
@ -224,8 +227,14 @@ public class MzLoader extends AbstractLibrarySupportLoader {
int numUninitBytes = 0;
if (segmentFileOffset + numBytes > endOffset) {
int calcNumBytes = numBytes;
numBytes = endOffset - segmentFileOffset;
numUninitBytes = calcNumBytes - numBytes;
if (segmentFileOffset > endOffset) {
numBytes = 0;
numUninitBytes = calcNumBytes;
}
else {
numBytes = endOffset - segmentFileOffset;
numUninitBytes = calcNumBytes - numBytes;
}
}
if (numBytes > 0) {
MemoryBlock block = MemoryBlockUtils.createInitializedBlock(program, false,
@ -317,8 +326,10 @@ public class MzLoader extends AbstractLibrarySupportLoader {
SegmentedAddress relocationAddress = relocationFixup.address();
Status status = Status.FAILURE;
try {
memory.setShort(relocationAddress, (short) relocationFixup.segment());
status = Status.APPLIED;
if (relocationFixup.valid) {
memory.setShort(relocationAddress, (short) relocationFixup.segment());
status = Status.APPLIED;
}
}
catch (MemoryAccessException e) {
log.appendMsg(String.format("Failed to apply relocation: %s (%s)",
@ -456,9 +467,11 @@ public class MzLoader extends AbstractLibrarySupportLoader {
int value = Short.toUnsignedInt(reader.readShort(relocationFileOffset));
int relocatedSegment = (INITIAL_SEGMENT_VAL + value) & 0xffff;
fixups.add(new RelocationFixup(relocation, relocationAddress, relocationFileOffset,
relocatedSegment));
relocatedSegment, true));
}
catch (AddressOutOfBoundsException | IOException e) {
fixups.add(new RelocationFixup(relocation, relocationAddress, relocationFileOffset,
0, false));
log.appendMsg(String.format("Failed to process relocation: %s (%s)",
relocationAddress, e.getMessage()));
}
@ -476,8 +489,7 @@ public class MzLoader extends AbstractLibrarySupportLoader {
* @return The segmented addresses converted to a file offset
*/
private int addressToFileOffset(int segment, int offset, OldDOSHeader header) {
return (short) segment * 16 + offset +
paragraphsToBytes(Short.toUnsignedInt(header.e_cparhdr()));
return (segment << 4) + offset + paragraphsToBytes(Short.toUnsignedInt(header.e_cparhdr()));
}
/**