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Add an analyzer to detect DTB signatures in memory.
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src/main/java/devicetreeblob/DeviceTreeBlobAnalyzer.java
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| /* ### | ||
| * IP: GHIDRA | ||
| * | ||
| * Licensed under the Apache License, Version 2.0 (the "License"); | ||
| * you may not use this file except in compliance with the License. | ||
| * You may obtain a copy of the License at | ||
| * | ||
| * http://www.apache.org/licenses/LICENSE-2.0 | ||
| * | ||
| * Unless required by applicable law or agreed to in writing, software | ||
| * distributed under the License is distributed on an "AS IS" BASIS, | ||
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| * See the License for the specific language governing permissions and | ||
| * limitations under the License. | ||
| */ | ||
| package devicetreeblob; | ||
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| import java.text.ParseException; | ||
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| import javax.swing.SwingConstants; | ||
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| import devicetreeblob.parser.Dtb; | ||
| import devicetreeblob.parser.DtbParser; | ||
| import ghidra.app.services.AbstractAnalyzer; | ||
| import ghidra.app.services.AnalyzerType; | ||
| import ghidra.app.util.importer.MessageLog; | ||
| import ghidra.program.model.address.Address; | ||
| import ghidra.program.model.address.AddressSetView; | ||
| import ghidra.program.model.listing.Program; | ||
| import ghidra.program.model.mem.MemoryAccessException; | ||
| import ghidra.util.Msg; | ||
| import ghidra.util.exception.CancelledException; | ||
| import ghidra.util.task.TaskBuilder; | ||
| import ghidra.util.task.TaskLauncher; | ||
| import ghidra.util.task.TaskMonitor; | ||
| import io.kaitai.struct.ByteBufferKaitaiStream; | ||
| import io.kaitai.struct.KaitaiStream.ValidationGreaterThanError; | ||
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| public class DeviceTreeBlobAnalyzer extends AbstractAnalyzer { | ||
| private static byte[] DTB_SIGNATURE = new byte[] { -48, 13, -2, -19 }; | ||
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| public DeviceTreeBlobAnalyzer() { | ||
| super("Device Tree Blob Analyzer", "Find Device Tree signatures and import memory map information from them.", | ||
| AnalyzerType.BYTE_ANALYZER); | ||
| } | ||
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| @Override | ||
| public boolean getDefaultEnablement(Program program) { | ||
| return true; | ||
| } | ||
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| @Override | ||
| public boolean canAnalyze(Program program) { | ||
| return true; | ||
| } | ||
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| @Override | ||
| public boolean added(Program program, AddressSetView set, TaskMonitor monitor, MessageLog log) | ||
| throws CancelledException { | ||
| monitor.setMessage("Looking for DTB signatures..."); | ||
| Address search_from = set.getMinAddress(); | ||
| while (search_from != null) { | ||
| monitor.checkCancelled(); | ||
| Address found_addr = program.getMemory().findBytes(search_from, DTB_SIGNATURE, null, true, monitor); | ||
| if (found_addr != null) { | ||
| monitor.setMessage(String.format("Checking DTB signatures in %s...", found_addr.toString())); | ||
| try { | ||
| parseDtb(program, found_addr); | ||
| } catch (MemoryAccessException | ParseException e) { | ||
| Msg.error(getClass(), "Could not parse DTB file!", e); | ||
| } | ||
| search_from = found_addr.next(); | ||
| } else { | ||
| search_from = null; | ||
| } | ||
| } | ||
| return true; | ||
| } | ||
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| private void parseDtb(Program program, Address addr) throws MemoryAccessException, ParseException { | ||
| int len = parseDtbLength(program, addr); | ||
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| byte[] bytes = new byte[len]; | ||
| int read = program.getMemory().getBytes(addr, bytes); | ||
| if (read < len) | ||
| throw new ParseException("Not enough bytes to parse DTB.", read); | ||
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| DtbParser parser = new DtbParser(bytes); | ||
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| DtbLoadTask loadTask = new DtbLoadTask(program, parser); | ||
| TaskBuilder.withTask(loadTask).setStatusTextAlignment(SwingConstants.LEADING).setLaunchDelay(0); | ||
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| new TaskLauncher(loadTask); | ||
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| // TODO Create a DTB byte array in memory | ||
| } | ||
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| private int parseDtbLength(Program program, Address addr) throws MemoryAccessException, ParseException { | ||
| byte[] header = new byte[40]; | ||
| int read = program.getMemory().getBytes(addr, header); | ||
| if (read < 40) | ||
| throw new ParseException("Not enough bytes to parse DTB header.", read); | ||
| Dtb dtb = null; | ||
| try { | ||
| dtb = new Dtb(new ByteBufferKaitaiStream(header)); | ||
| } catch (ValidationGreaterThanError e) { | ||
| throw new ParseException("Wrong DTB format.", 0); | ||
| } | ||
| long len = dtb.totalSize(); | ||
| if (len < 40) | ||
| // Full DTB cannot be shorter than its header... | ||
| throw new ParseException("Wrong DTB length signature.", 0); | ||
| if (dtb.ofsStructureBlock() < 40) | ||
| throw new ParseException("Offset of structure block cannot be lower than header size.", 0); | ||
| if ((dtb.ofsStructureBlock() & 0x3) != 0) | ||
| throw new ParseException("Offset of structure must be aligned to a 4 byte boundary.", 0); | ||
| if (dtb.lenStructureBlock() <= 0) | ||
| throw new ParseException("Len of structure block cannot be zero or negative.", 0); | ||
| if (dtb.ofsStringsBlock() < 40) | ||
| throw new ParseException("Offset of strings block cannot be lower than header size.", 0); | ||
| if (dtb.lenStringsBlock() <= 0) | ||
| throw new ParseException("Len of strings block cannot be zero or negative.", 0); | ||
| if (dtb.version() > 30) | ||
| throw new ParseException("Invalid FDT version.", 0); | ||
| return (int) len; | ||
| } | ||
| } |
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