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GP-4889: Detect patches to program counter.

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This commit is contained in:
Dan 2024-09-13 14:34:18 -04:00
parent e5aa0e8e5b
commit 491e6a3c23
1 changed files with 42 additions and 12 deletions
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48
Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/model/time/schedule/PatchStep.java
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@ -82,6 +82,10 @@ public class PatchStep implements Step {
/**
* Generate a single line of Sleigh
*
* @param language the target language
* @param address the (start) address of the variable
* @param data the bytes to write to the variable
* @return the Sleigh code
* @see #generateSleighLine(Language, Address, byte[], int)
*/
public static String generateSleighLine(Language language, Address address, byte[] data) {
@ -169,10 +173,18 @@ public class PatchStep implements Step {
if (register == null) {
throw new IllegalArgumentException("Could not find a register for " + min);
}
if (register.getBaseRegister().isProgramCounter()) {
register = register.getBaseRegister();
}
int length = register.getNumBytes();
array.getData(min.getOffset(), data, 0, length);
array.getData(register.getOffset(), data, 0, length);
BigInteger value = Utils.bytesToBigInteger(data, length, language.isBigEndian(), false);
if (register.isProgramCounter()) {
result.add(String.format("goto 0x%s", value.toString(16)));
}
else {
result.add(String.format("%s=0x%s", register, value.toString(16)));
}
remains.remove(spanOfRegister(register));
}
}
@ -366,22 +378,28 @@ public class PatchStep implements Step {
// SemisparseArray is a bit overkill, no?
Map<AddressSpace, SemisparseByteArray> result = new TreeMap<>();
for (PcodeOp op : prog.getCode()) {
// Only accept patches in form [mem/reg] = [constant]
// Only accept patches in form [mem/reg] = [constant], or goto [constant]
switch (op.getOpcode()) {
case PcodeOp.COPY:
case PcodeOp.COPY -> {
if (!getPatchCopyOp(language, result, op)) {
return null;
}
break;
case PcodeOp.STORE:
}
case PcodeOp.STORE -> {
if (!getPatchStoreOp(language, result, op)) {
return null;
}
break;
default:
}
case PcodeOp.BRANCH -> {
if (!getPatchBranchOp(language, result, op)) {
return null;
}
}
default -> {
return null;
}
}
}
return result;
}
@ -405,8 +423,7 @@ public class PatchStep implements Step {
}
protected boolean getPatchStoreOp(Language language,
Map<AddressSpace, SemisparseByteArray> result,
PcodeOp op) {
Map<AddressSpace, SemisparseByteArray> result, PcodeOp op) {
Varnode vnSpace = op.getInput(0);
if (!vnSpace.isConstant()) {
return false;
@ -427,4 +444,17 @@ public class PatchStep implements Step {
return true;
}
protected boolean getPatchBranchOp(Language language,
Map<AddressSpace, SemisparseByteArray> result, PcodeOp op) {
Address target = op.getInput(0).getAddress();
if (target.getAddressSpace() != language.getDefaultSpace()) {
return false;
}
Register pc = language.getProgramCounter();
SemisparseByteArray array =
result.computeIfAbsent(pc.getAddressSpace(), as -> new SemisparseByteArray());
array.putData(pc.getOffset(),
Utils.longToBytes(target.getOffset(), pc.getNumBytes(), language.isBigEndian()));
return true;
}
}