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ghidra: fix invalid address expection and handle partial union #81

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Merged
merged 2 commits into from
May 16, 2025
Merged

ghidra: fix invalid address expection and handle partial union #81

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a1697ce
ghidra: fix invalid address expection and handle partial union
kumarak May 16, 2025
444f4e3
ghidra: fix early handling of exceptions
kumarak May 16, 2025
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34 changes: 25 additions & 9 deletions lib/patchestry/Ghidra/JsonDeserialize.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -199,7 +199,7 @@ namespace patchestry::ghidra {
auto size = static_cast< uint32_t >(type_obj.getInteger("size").value_or(0));
auto kind_str = get_string(type_obj, "kind");
LOG(INFO) << "Attempting to convert kind string: [" << kind_str << "]" << "\n";
auto kind = VarnodeType::convertToKind(kind_str);
auto kind = VarnodeType::convertToKind(kind_str);
switch (kind) {
case VarnodeType::Kind::VT_INVALID: {
LOG(ERROR) << "Invalid varnode type: " << name << "\n";
Expand Down Expand Up @@ -324,40 +324,56 @@ namespace patchestry::ghidra {
}

// Iterate through the fields and initialize them
unsigned field_index = 0;
for (const auto &field : *field_array) {
const auto *field_obj = field.getAsObject();
if (field_obj == nullptr) {
LOG(ERROR) << "Skipping invalid field object.\n";
LOG(ERROR) << "Field #" << field_index
<< ": Invalid field object format, skipping\n";
++field_index;
continue;
}

auto field_type_key = get_string_if_valid(*field_obj, "type");
if (!field_type_key) {
LOG(ERROR) << "Skipping field: missing type\n";
LOG(ERROR) << "Field #" << field_index
<< ": Missing required 'type' attribute, skipping\n";
++field_index;
continue;
}

auto iter = serialized_types.find(*field_type_key);
if (iter == serialized_types.end()) {
LOG(ERROR) << "Skipping field: component is not found on serialized types.\n";
LOG(ERROR) << "Field #" << field_index << ": Type '" << *field_type_key
<< "' not found in serialized types registry, skipping\n";
++field_index;
continue;
}

auto maybe_offset = field_obj->getInteger("offset");
if (!maybe_offset) {
LOG(ERROR) << "Skipping field: invalid offset value.\n";
LOG(ERROR) << "Field #" << field_index
<< ": Missing or invalid 'offset' value, skipping\n";
++field_index;
continue;
}

std::string field_name;
auto maybe_name = get_string_if_valid(*field_obj, "name");
if (!maybe_name) {
LOG(ERROR) << "Skipping field: invalid name.\n";
continue;
if (maybe_name) {
field_name = *maybe_name;
} else {
field_name = "field_" + std::to_string(field_index);
LOG(WARNING) << "Field #" << field_index
<< " Missing or invalid name, using default: '" << field_name
<< "'\n";
}

varnode.add_components(
*maybe_name, *iter->second, static_cast< uint32_t >(*maybe_offset)
field_name, *iter->second, static_cast< uint32_t >(*maybe_offset)
);

++field_index;
}
}

Expand Down
52 changes: 45 additions & 7 deletions scripts/ghidra/PatchestryDecompileFunctions.java
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
import ghidra.program.model.address.AddressSet;
import ghidra.program.model.address.AddressSetView;
import ghidra.program.model.address.AddressSpace;
import ghidra.program.model.address.AddressOutOfBoundsException;

import ghidra.program.model.block.BasicBlockModel;
import ghidra.program.model.block.CodeBlock;
Expand Down Expand Up @@ -576,9 +577,13 @@ private void serialize(DataType data_type) throws Exception {
serializePrototype((FunctionSignature) data_type);

} else if (data_type instanceof PartialUnion) {
name("kind").value("todo:PartialUnion"); // TODO(pag): Implement this
name("size").value(data_type.getLength());

DataType parent = ((PartialUnion) data_type).getParent();
if (parent != data_type) {
serialize(parent);
} else {
// PartialUnion stripped type is undefined type
serialize(((PartialUnion) data_type).getStrippedDataType());
}
} else if (data_type instanceof BitFieldDataType) {
name("kind").value("todo:BitFieldDataType"); // TODO(pag): Implement this
name("size").value(data_type.getLength());
Expand Down Expand Up @@ -846,7 +851,20 @@ private Address convertAddressToRamSpace(Address address) throws Exception {
if (address == null) {
return null;
}
return ram_space.getAddress(address.toString(false));

try {
// If already in RAM space, just return it
if (address.getAddressSpace().getName().equals("ram")) {
return address;
}

// Get the numeric offset and create a new address in RAM space
long offset = address.getOffset();
return program.getAddressFactory().getDefaultAddressSpace().getAddress(offset);
} catch (Exception e) {
println(String.format("Failed to convert address %s to RAM space: %s", address, e.getMessage()));
return null;
}
}

private boolean isCharPointer(Varnode node) throws Exception {
Expand Down Expand Up @@ -875,6 +893,9 @@ private String findNullTerminatedString(Address address, Pointer pointer) throws
}

Address ram_address = convertAddressToRamSpace(address);
if (ram_address == null) {
return null;
}
MemoryBufferImpl memoryBuffer = new MemoryBufferImpl(program.getMemory(), ram_address);
DataType char_type = pointer.getDataType();
//println("Debug: char_type = " + char_type.getName() + ", size = " + char_type.getLength());
Expand All @@ -891,14 +912,31 @@ private String findNullTerminatedString(Address address, Pointer pointer) throws
}

private Data getDataReferencedAsConstant(Varnode node) throws Exception {
// check if node is null
if (node == null) {
return null;
}

// Only process constant nodes that aren't nulls (address 0 in constant space)
if (!node.isConstant() || node.getAddress().equals(constant_space.getAddress(0))) {
return null;
}

// Ghidra sometime fail to resolve references to Data and show it as const.
// Check if it is referencing Data as constant from `ram` addresspace.
Address ram_address = convertAddressToRamSpace(node.getAddress());
Data data = getDataAt(ram_address);
return data;
try {
// Convert the constant value to a potential RAM address
Address ram_address = convertAddressToRamSpace(node.getAddress());
if (ram_address == null) {
return null;
}
return getDataAt(ram_address);

} catch (AddressOutOfBoundsException e) {
println("Address conversion out of bounds for constant: " + e.getMessage());
}

return null;
}

// Serialize an input or output varnode.
Expand Down