diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..67dc997 --- /dev/null +++ b/.gitignore @@ -0,0 +1,69 @@ +/.gradle/ +/.settings/ +.project +.classpath +.antProperties.xml + +.DS_Store + +# Eclipse.gitignore below +.metadata +bin/ +tmp/ +*.tmp +*.bak +*.swp +*~.nib +local.properties +.settings/ +.loadpath +.recommenders + +# External tool builders +.externalToolBuilders/ + +# Locally stored "Eclipse launch configurations" +*.launch + +# PyDev specific (Python IDE for Eclipse) +*.pydevproject + +# CDT-specific (C/C++ Development Tooling) +.cproject + +# CDT- autotools +.autotools + +# Java annotation processor (APT) +.factorypath + +# PDT-specific (PHP Development Tools) +.buildpath + +# sbteclipse plugin +.target + +# Tern plugin +.tern-project + +# TeXlipse plugin +.texlipse + +# STS (Spring Tool Suite) +.springBeans + +# Code Recommenders +.recommenders/ + +# Annotation Processing +.apt_generated/ +.apt_generated_test/ + +# Scala IDE specific (Scala & Java development for Eclipse) +.cache-main +.scala_dependencies +.worksheet + +# Uncomment this line if you wish to ignore the project description file. +# Typically, this file would be tracked if it contains build/dependency configurations: +#.project diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..30c6c64 --- /dev/null +++ b/LICENSE @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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Interpretation of Sections 15 and 16. + + If the disclaimer of warranty and limitation of liability provided +above cannot be given local legal effect according to their terms, +reviewing courts shall apply local law that most closely approximates +an absolute waiver of all civil liability in connection with the +Program, unless a warranty or assumption of liability accompanies a +copy of the Program in return for a fee. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. 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If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Ghostrings Copyright (C) 2022 NCC Group + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. \ No newline at end of file diff --git a/Module.manifest b/Module.manifest new file mode 100644 index 0000000..e69de29 diff --git a/README.md b/README.md new file mode 100644 index 0000000..a36342c --- /dev/null +++ b/README.md @@ -0,0 +1,103 @@ +# Ghostrings + +Scripts for recovering string definitions in Go binaries with P-Code analysis. +Tested with x86, x86-64, ARM, and ARM64. + +There are two main parts to the string recovery flow with Ghostrings: + +* Find dynamic string structure definitions on the stack via P-Code analysis, then use their start address and length values to define strings in the `go.string.*` string data blob +* Fill the remaining gaps in `go.string.*` using some mathematical checks, based on the ascending length order of the strings + +These two techniques greatly simplify recovering all string definitions in the `go.string.*` blob with minimal manual intervention. + +### Background + +A well-known issue with reverse engineering Go programs is that the lack of null terminators in Go strings makes recovering string definitions from compiled binaries difficult. Many of a Go program's constant string values are stored together in one giant blob in the compiled build, without any terminator characters built into the string data to mark where one string ends and another begins. Even a simple program that just prints "Hello world!" has over 1,500 strings in it related to the Go runtime system and other standard libraries. This can cause typical ASCII string discovery implementations, such as the one provided by Ghidra, to create false positive string definitions that are tens of thousands of characters long. + +Instead of null terminated strings, Go uses a string structure that consists of a pointer and length value. Many of these string structures are created on the program’s stack at runtime, so recovering individual string start locations and length values requires analyzing the compiled machine code. There are a few existing scripts that perform this analysis by checking for certain patterns of x86-64 instructions, but they miss structures created with unhandled variations of instructions that ultimately have the same effect on the stack, and they're also restricted to a specific ISA. + +Ghostrings avoids both these problems by working with the simplified, architecture independent P-Code operations produced by Ghidra’s decompiler analysis. + +## Setup + +### Installing + +In Ghidra: + +1. File -> Install Extensions -> Add extension +2. Select the extension ZIP file + +### Development + +For Eclipse with GhidraDev plugin: + +1. Clone repo +2. File -> Import -> Projects from Folder or Archive +3. Select repo directory +4. GhidraDev -> Link Ghidra... +5. Select imported project + +### Building + +Build with Eclipse: + +* GhidraDev -> Export -> Ghidra Module Extension... + +Build directly with Gradle: + +```console +$ cd Ghostrings +$ gradle -PGHIDRA_INSTALL_DIR= +``` + +## Scripts + +### Golang + +These can be found in the Golang category in the Script Manager. + +* `GoDynamicStrings.java` + * Analyzes P-Code to find string structures created on the stack. Uses the lower level "register" style analysis. +* `GoDynamicStringsSingle.java` + * Performs the same analysis as `GoDynamicStrings.java`, but uses a single decompiler process. Use this if analyzing a large binary causes the parallel decompiler processes to exhaust system memory. +* `GoDynamicStringsHigh.java` + * Experimental, uses P-Code output from the higher level "normalize" style analysis. Currently depends on a hack that turns off deadcode elimination in the decompiler. +* `GoKnownStrings.java` + * Searches for standard unique strings and defines them. +* `GoStringFiller.java` + * Fills in gaps in `go.string.*` after initial analysis, based on strings being ordered by ascending length. + +### P-Code + +This can be found in the PCode category in the Script Manager. + +* `PrintHighPCode.java` + * Prints high P-Code output for the currently selected function to the console, with a selector for the decompiler simplification style to use. + + +## String recovery flow + +Here’s the general flow for using these scripts to recover string definitions in a Go binary: + +1. Clear all automatically defined strings in the `.rodata` (ELF) or `.rdata` (PE) memory block. The goal is to eliminate incorrect string definitions caused by the lack of null terminators. + 1. In the "Defined Strings" window, add the "Mem Block" column to the display + 2. Create a filter on the memory block column to only show strings in the target block + 3. Select all strings in the window, then in the listing right-click and choose "Clear Code Bytes" +2. Run `GoDynamicStrings.java` or `GoDynamicStringsHigh.java`. +3. *(Optional)* Run `GoKnownStrings.java` to detect some standard strings. +4. Run `GoStringFiller.java`. + * If it detects false positive short strings (strings that violate the ascending length order), clear them and re-run the script. There is an option to do this automatically. + * There’s an option to allow the script to define strings even when a unique set of string lengths can’t be identified, as a last resort. Specifically, there’s one rule that checks if a gap’s size is evenly divisible only by a single string length. It’s possible there are actually strings of different lengths in the gap, but this works often enough to be useful. I recommend running the script without allowing false positives until all the short strings have been fixed. + * If the binary is stripped, locate the area of one byte strings found by the dynamic strings script. + Ensure it's the start of the grouped together non-null-terminated strings (more strings should be defined after with length in ascending order). + Create the label `go.string.*` at the first one byte string.  +5. Check for remaining gaps in `go.string.*`, and define any strings with obvious start and end points. Sometimes defining one or two strings and re-running `GoStringFiller.java` is sufficient to fill in remaining gaps. +6. *(Optional)* Re-run Ghidra's built-in ASCII String analysis tool. + * Disable overwriting existing strings. Run with and then without the null terminator requirement. + + +## Release Info + +Copyright 2022 NCC Group. Released under the GPLv3 license (see LICENSE). + +Main project author: James Chambers diff --git a/build.gradle b/build.gradle new file mode 100644 index 0000000..cddd995 --- /dev/null +++ b/build.gradle @@ -0,0 +1,60 @@ +/* ### + * 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. + */ +// Builds a Ghidra Extension for a given Ghidra installation. +// +// An absolute path to the Ghidra installation directory must be supplied either by setting the +// GHIDRA_INSTALL_DIR environment variable or Gradle project property: +// +// > export GHIDRA_INSTALL_DIR= +// > gradle +// +// or +// +// > gradle -PGHIDRA_INSTALL_DIR= +// +// Gradle should be invoked from the directory of the project to build. Please see the +// application.gradle.version property in /Ghidra/application.properties +// for the correction version of Gradle to use for the Ghidra installation you specify. + +//----------------------START "DO NOT MODIFY" SECTION------------------------------ +def ghidraInstallDir + +if (System.env.GHIDRA_INSTALL_DIR) { + ghidraInstallDir = System.env.GHIDRA_INSTALL_DIR +} +else if (project.hasProperty("GHIDRA_INSTALL_DIR")) { + ghidraInstallDir = project.getProperty("GHIDRA_INSTALL_DIR") +} + +if (ghidraInstallDir) { + apply from: new File(ghidraInstallDir).getCanonicalPath() + "/support/buildExtension.gradle" +} +else { + throw new GradleException("GHIDRA_INSTALL_DIR is not defined!") +} +//----------------------END "DO NOT MODIFY" SECTION------------------------------- + +repositories { + // Declare dependency repositories here. This is not needed if dependencies are manually + // dropped into the lib/ directory. + // See https://docs.gradle.org/current/userguide/declaring_repositories.html for more info. + // Ex: mavenCentral() +} + +dependencies { + // Any external dependencies added here will automatically be copied to the lib/ directory when + // this extension is built. +} diff --git a/build/.gitignore b/build/.gitignore new file mode 100644 index 0000000..94548af --- /dev/null +++ b/build/.gitignore @@ -0,0 +1,3 @@ +* +*/ +!.gitignore diff --git a/data/README.txt b/data/README.txt new file mode 100644 index 0000000..1222f67 --- /dev/null +++ b/data/README.txt @@ -0,0 +1,15 @@ +The "data" directory is intended to hold data files that will be used by this module and will +not end up in the .jar file, but will be present in the zip or tar file. Typically, data +files are placed here rather than in the resources directory if the user may need to edit them. + +An optional data/languages directory can exist for the purpose of containing various Sleigh language +specification files and importer opinion files. + +The data/buildLanguage.xml is used for building the contents of the data/languages directory. + +The skel language definition has been commented-out within the skel.ldefs file so that the +skeleton language does not show-up within Ghidra. + +See the Sleigh language documentation (docs/languages/index.html) for details Sleigh language +specification syntax. + \ No newline at end of file diff --git a/dist/.gitignore b/dist/.gitignore new file mode 100644 index 0000000..94548af --- /dev/null +++ b/dist/.gitignore @@ -0,0 +1,3 @@ +* +*/ +!.gitignore diff --git a/extension.properties b/extension.properties new file mode 100644 index 0000000..60b53ad --- /dev/null +++ b/extension.properties @@ -0,0 +1,5 @@ +name=@extname@ +description=Tools for recovering strings in Go binaries. +author=James Chambers +createdOn=4/4/2022 +version=@extversion@ diff --git a/ghidra_scripts/GoDynamicStrings.java b/ghidra_scripts/GoDynamicStrings.java new file mode 100644 index 0000000..fb70c52 --- /dev/null +++ b/ghidra_scripts/GoDynamicStrings.java @@ -0,0 +1,486 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +//Find Go strings dynamically allocated on the stack (P-Code based). +//Clearing out all automatically defined strings in .rodata/.rdata first is recommended. +//The built-in ASCII Strings analysis can then be run again afterwards, +//with the option to clear existing strings disabled. +// +//This version uses the decompiler's "register" simplification style, +//which applies relatively few analysis rules. The resulting PCode output is +//more difficult to work with, but currently more reliable than the +//higher level version of the script. +//@author James Chambers +//@category Golang +//@keybinding +//@menupath +//@toolbar + +import java.util.Arrays; +import java.util.HashSet; +import java.util.Iterator; +import java.util.List; +import java.util.Set; +import java.util.function.Consumer; + +import ghidra.app.decompiler.DecompInterface; +import ghidra.app.decompiler.DecompileOptions; +import ghidra.app.decompiler.DecompileResults; +import ghidra.app.decompiler.parallel.DecompileConfigurer; +import ghidra.app.decompiler.parallel.DecompilerCallback; +import ghidra.app.decompiler.parallel.ParallelDecompiler; +import ghidra.app.script.GhidraScript; +import ghidra.app.script.GhidraState; +import ghidra.framework.options.ToolOptions; +import ghidra.framework.plugintool.PluginTool; +import ghidra.framework.plugintool.util.OptionsService; +import ghidra.program.model.address.Address; +import ghidra.program.model.listing.Data; +import ghidra.program.model.listing.Function; +import ghidra.program.model.listing.FunctionIterator; +import ghidra.program.model.listing.Program; +import ghidra.program.model.pcode.HighFunction; +import ghidra.program.model.pcode.PcodeOp; +import ghidra.program.model.pcode.PcodeOpAST; +import ghidra.program.model.pcode.Varnode; +import ghidra.util.StringUtilities; +import ghidra.util.exception.CancelledException; +import ghidra.util.task.TaskMonitor; +import ghostrings.AddressCandidate; +import ghostrings.GhostringsUtil; +import ghostrings.LengthCandidate; +import ghostrings.exceptions.DuplicateDataException; +import ghostrings.exceptions.UnhandledOpArgsException; +import ghostrings.exceptions.UnhandledOpTypeException; + +public class GoDynamicStrings extends GhidraScript { + + protected final static String CHOICE_CUR_FUNC = "Selected function"; + protected final static String CHOICE_ALL_FUNCS = "All functions"; + + protected final static long MIN_STR_LEN = 1; + protected final static long MAX_STR_LEN = 0x4000; + protected final static Set STR_MEM_BLOCKS; + static { + STR_MEM_BLOCKS = new HashSet<>(); + STR_MEM_BLOCKS.add(".rodata"); + STR_MEM_BLOCKS.add(".rdata"); + } + + protected int verbose; + protected final String printfPrefix = getScriptName().replace("%", "%%") + "> "; + + protected String getSimplificationStyle() { + return "register"; + } + + protected DecompileOptions makeDecompileOptions(GhidraState state) { + DecompileOptions options = new DecompileOptions(); + + PluginTool tool = state.getTool(); + if (tool != null) { + OptionsService service = tool.getService(OptionsService.class); + if (service != null) { + ToolOptions opt = service.getOptions("Decompiler"); + options.grabFromToolAndProgram(null, opt, state.getCurrentProgram()); + } + } + + options.setEliminateUnreachable(false); + + return options; + } + + protected static final class GoStringDecompConfigurer implements DecompileConfigurer { + + private DecompileOptions options; + private String simplificationStyle; + + public GoStringDecompConfigurer(DecompileOptions options, String simplificationStyle) { + this.options = options; + this.simplificationStyle = simplificationStyle; + } + + @Override + public void configure(DecompInterface decompiler) { + decompiler.setOptions(options); + decompiler.toggleCCode(false); + decompiler.toggleSyntaxTree(true); + decompiler.toggleParamMeasures(false); + decompiler.setSimplificationStyle(simplificationStyle); + } + + } + + protected static final class GoStringDecompCallback extends DecompilerCallback { + + public GoStringDecompCallback(Program program, DecompileConfigurer configurer) { + super(program, configurer); + } + + @Override + public DecompileResults process(DecompileResults results, TaskMonitor monitor1) throws Exception { + if (monitor1.isCancelled()) { + return null; + } + long progress = monitor1.getProgress() + 1; + monitor1.setProgress(progress); + + return results; + } + + } + + protected final class GoStringDecompConsumer implements Consumer { + + @Override + public void accept(DecompileResults results) { + if (results == null) { + return; + } + + Function func = results.getFunction(); + + String decompError = results.getErrorMessage(); + if (decompError != null && decompError.length() > 0) { + printf("Decompiler error for %s: %s\n", GhostringsUtil.funcNameAndAddr(func), + decompError.trim()); + } + + if (!results.decompileCompleted()) { + printf("Decompilation not completed for %s\n", GhostringsUtil.funcNameAndAddr(func)); + return; + } + + HighFunction highFunc = results.getHighFunction(); + detectFunctionStrings(highFunc); + } + + } + + /** Make printf log prefix consistent with println */ + @Override + public void printf(String message, Object... args) { + super.printf(printfPrefix + message, args); + } + + protected void printPcodeOp(PcodeOpAST pcodeOpAST) { + printf("PcodeOp @ target 0x%x, order %02d, time 0x%02x: %s\n", + pcodeOpAST.getSeqnum().getTarget().getOffset(), + pcodeOpAST.getSeqnum().getOrder(), + pcodeOpAST.getSeqnum().getTime(), + pcodeOpAST.toString()); + } + + protected AddressCandidate storeDataCheck(Program program, PcodeOpAST pcodeOpAST) { + if (pcodeOpAST.getOpcode() != PcodeOp.STORE) + return null; + + if (getVerbose() > 0) { + printf("* data check: pcode store op @ %x : seq %d\n", + pcodeOpAST.getSeqnum().getTarget().getOffset(), + pcodeOpAST.getSeqnum().getOrder()); + } + + // Get input, make sure it's a valid address + Varnode dataToStore = pcodeOpAST.getInput(2); + + Address candidateAddr = null; + + if (dataToStore.isConstant()) { + // Constant may be an address + candidateAddr = GhostringsUtil.addrFromConstant(program, dataToStore); + } else if (dataToStore.isRegister()) { + // Register may hold an address + PcodeOp def = dataToStore.getDef(); + // Check for LOAD op that loaded an address into the register, + // e.g. getting address from constant pool in ARM 32 + if (def != null && def.getOpcode() == PcodeOp.LOAD) { + Address loadFrom = GhostringsUtil.getLoadStoreAddr(def, program.getAddressFactory()); + Data dataLoaded = getDataAt(loadFrom); + if (dataLoaded != null && dataLoaded.isPointer()) { + candidateAddr = (Address) dataLoaded.getValue(); + } + } + } + + if (candidateAddr == null) { + return null; + } + + // Check if the address is in .rodata + String blockName = GhostringsUtil.memBlockName(program, candidateAddr); + if (!STR_MEM_BLOCKS.contains(blockName)) + return null; + + // If output is a stack address, get the offset + Varnode storeLoc = pcodeOpAST.getInput(1); + + Long stackOffset = null; + try { + stackOffset = GhostringsUtil.outputStackOffset(program, storeLoc); + } catch (UnhandledOpTypeException | UnhandledOpArgsException e) { + println(e.getMessage()); + } + + if (stackOffset == null) { + if (getVerbose() > 1) + println("Couldn't get an SP offset for the output varnode"); + return null; + } + + if (getVerbose() > 0) { + Address destAddr = GhostringsUtil.getLoadStoreAddr(pcodeOpAST, program.getAddressFactory()); + printf("copy %s to addr. %s\n", candidateAddr.toString(), destAddr.toString(true)); + } + + AddressCandidate result = new AddressCandidate(candidateAddr, stackOffset, pcodeOpAST); + return result; + } + + protected LengthCandidate storeLenCheck(Program program, PcodeOpAST pcodeOpAST) { + if (pcodeOpAST.getOpcode() != PcodeOp.STORE) + return null; + + if (getVerbose() > 0) { + printf("* length check: pcode store op @ %x : seq %d\n", + pcodeOpAST.getSeqnum().getTarget().getOffset(), + pcodeOpAST.getSeqnum().getOrder()); + } + + // Get input, make sure it's a constant + Varnode dataToStore = pcodeOpAST.getInput(2); + if (!dataToStore.isConstant()) + return null; + + long constantValue = dataToStore.getAddress().getOffset(); + + // Simple string length bounds check + if (constantValue < MIN_STR_LEN || constantValue > MAX_STR_LEN) { + return null; + } + + // If output is a stack address, get the offset + Varnode storeLoc = pcodeOpAST.getInput(1); + + Long stackOffset = null; + try { + stackOffset = GhostringsUtil.outputStackOffset(program, storeLoc); + } catch (UnhandledOpTypeException | UnhandledOpArgsException e) { + println(e.getMessage()); + } + + if (stackOffset == null) { + if (getVerbose() > 1) + println("Couldn't get an SP offset for the output varnode"); + return null; + } + + if (getVerbose() > 0) { + Address destAddr = GhostringsUtil.getLoadStoreAddr(pcodeOpAST, program.getAddressFactory()); + + printf("copy constant 0x%x to addr. %s\n", + constantValue, + destAddr.toString(true)); + } + + LengthCandidate result = new LengthCandidate((int) constantValue, stackOffset, pcodeOpAST); + return result; + } + + protected String checkForString(AddressCandidate addrCandidate, LengthCandidate lenCandidate) { + final int ptrSize = currentProgram.getDefaultPointerSize(); + + if (lenCandidate.getStackOffset() - addrCandidate.getStackOffset() != ptrSize) { + return null; + } + + return GhostringsUtil.checkForString( + currentProgram, + addrCandidate.getStringAddr(), + lenCandidate.getStringLength()); + } + + protected void detectFunctionStrings(HighFunction highFunc) { + Function func = highFunc.getFunction(); + + if (getVerbose() > 0) + printf("local dynamic string header analysis of %s\n", GhostringsUtil.funcNameAndAddr(func)); + + AddressCandidate storeData = null; + LengthCandidate storeLen = null; + LengthCandidate storeLenOld = null; + + /* + * TODO: For main analysis loop, need to consider that a single Pcode op can + * generate multiple address/length candidates in order to handle MULTIEQUAL. + * There can also be pointers to string structs in .rodata, which could be + * handled as a single op producing an address and length candidate. + */ + + Iterator ops = highFunc.getPcodeOps(); + while (ops.hasNext() && !monitor.isCancelled()) { + PcodeOpAST pcodeOpAST = ops.next(); + + if (getVerbose() > 1) + printPcodeOp(pcodeOpAST); + + boolean opIdentified = false; + + // Check for string address or length store + AddressCandidate addrCheck = storeDataCheck(currentProgram, pcodeOpAST); + if (addrCheck != null) { + opIdentified = true; + storeData = addrCheck; + + // Only keep track of one length store that came before the address store + if (storeLen != null) { + storeLenOld = storeLen; + storeLen = null; + } + } else { + LengthCandidate lenCheck = storeLenCheck(currentProgram, pcodeOpAST); + if (lenCheck != null) { + opIdentified = true; + if (storeLen != null) { + storeLenOld = storeLen; + } + storeLen = lenCheck; + } + } + + // funcCallCheck was here to test working with calls that ate up stack variables + + if (!opIdentified) { + // Nothing new to check found + continue; + } + + // When an address and length are set, check for string + if (storeData != null && storeLen != null) { + // Try with length op after address op + String checkString = checkForString(storeData, storeLen); + if (checkString != null) { + // clear current possible length if it's used + storeLen = null; + } else if (storeLenOld != null) { + // Try with length op before address op + checkString = checkForString(storeData, storeLenOld); + } + + if (checkString != null) { + Address stringAddr = storeData.getStringAddr(); + // When a string is found, always clear possible address and old possible length + storeData = null; + storeLenOld = null; + + final String strDesc = String.format("@ %s: \"%s\"", + stringAddr.toString(), + StringUtilities.convertControlCharsToEscapeSequences(checkString)); + try { + boolean defineSucceeded = GhostringsUtil.tryDefString( + this, stringAddr, checkString, getVerbose()); + if (defineSucceeded) { + println("* Define succeeded " + strDesc); + } else { + println("* Define failed " + strDesc); + } + } catch (DuplicateDataException e) { + // This exact string is already defined + println("* Already defined " + strDesc); + } catch (Exception e) { + // removeData just throws Exception :\ + println("* Define failed with exception: " + e.getMessage()); + } + } + } + + } + + if (getVerbose() > 0) + printf("exit analysis of %s\n", GhostringsUtil.funcNameAndAddr(func)); + } + + protected String askTargetChoice() throws CancelledException { + final List choices = Arrays.asList(CHOICE_CUR_FUNC, CHOICE_ALL_FUNCS); + + return askChoice("Go String Analyzer Mode", + "Analyze currently selected function or all functions?", + choices, + CHOICE_CUR_FUNC); + } + + protected void analyzeFunctions(Iterator functions) throws Exception { + DecompileOptions opts = makeDecompileOptions(state); + GoStringDecompConfigurer configurer = new GoStringDecompConfigurer(opts, getSimplificationStyle()); + GoStringDecompCallback callback = new GoStringDecompCallback(currentProgram, configurer); + GoStringDecompConsumer consumer = new GoStringDecompConsumer(); + + ParallelDecompiler.decompileFunctions( + callback, currentProgram, functions, consumer, monitor); + + callback.dispose(); + } + + public void run() throws Exception { + setVerbose(0); + + println("Start Go string finder"); + + // Ask user to analyze selected function or all functions + final String selectedMode; + try { + selectedMode = askTargetChoice(); + } catch (CancelledException e) { + println("Script cancelled"); + return; + } + + if (CHOICE_ALL_FUNCS.equals(selectedMode)) { + // Iterate all functions + int funcCount = currentProgram.getFunctionManager().getFunctionCount(); + monitor.setMaximum(funcCount); + monitor.setProgress(0); + monitor.setIndeterminate(false); + + FunctionIterator fIter = currentProgram.getFunctionManager().getFunctionsNoStubs(true); + analyzeFunctions(fIter); + } else { + // Check currently selected function + Function func = getFunctionContaining(currentAddress); + if (func == null) { + final String msg = "No function selected"; + println(msg); + popup(msg); + } else { + monitor.setIndeterminate(true); + monitor.setMessage("Analyzing " + GhostringsUtil.getFuncName(func)); + println("Analyzing function " + GhostringsUtil.funcNameAndAddr(func)); + analyzeFunctions(Arrays.asList(func).iterator()); + } + } + } + + protected int getVerbose() { + return verbose; + } + + protected void setVerbose(int verbose) { + this.verbose = verbose; + } + +} diff --git a/ghidra_scripts/GoDynamicStringsHigh.java b/ghidra_scripts/GoDynamicStringsHigh.java new file mode 100644 index 0000000..f94e67f --- /dev/null +++ b/ghidra_scripts/GoDynamicStringsHigh.java @@ -0,0 +1,171 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +//Find Go strings dynamically allocated on the stack (P-Code based). +//Clearing out all automatically defined strings in .rodata/.rdata first is recommended. +//The built-in ASCII Strings analysis can then be run again afterwards, +//with the option to clear existing strings disabled. +// +//This version uses a hack combined with the "normalize" simplification +//style to preserve nicer COPY operations in the PCode output, +//which clearly indicate a constant value being copied to the stack. +//@author James Chambers +//@category Golang +//@keybinding +//@menupath +//@toolbar + +import ghidra.app.decompiler.DecompileOptions; +import ghidra.app.script.GhidraState; +import ghidra.framework.options.ToolOptions; +import ghidra.framework.plugintool.PluginTool; +import ghidra.framework.plugintool.util.OptionsService; +import ghidra.program.model.address.Address; +import ghidra.program.model.address.AddressOutOfBoundsException; +import ghidra.program.model.listing.Program; +import ghidra.program.model.pcode.PcodeOp; +import ghidra.program.model.pcode.PcodeOpAST; +import ghidra.program.model.pcode.Varnode; +import ghostrings.AddressCandidate; +import ghostrings.GhostringsUtil; +import ghostrings.LengthCandidate; + +public class GoDynamicStringsHigh extends GoDynamicStrings { + + private static final String SIMPLIFICATION_STYLE = "normalize"; + + @Override + protected String getSimplificationStyle() { + return SIMPLIFICATION_STYLE; + } + + @Override + protected DecompileOptions makeDecompileOptions(GhidraState state) { + DecompileOptions options = new DecompileOptions(); + + PluginTool tool = state.getTool(); + if (tool != null) { + OptionsService service = tool.getService(OptionsService.class); + if (service != null) { + ToolOptions opt = service.getOptions("Decompiler"); + options.grabFromToolAndProgram(null, opt, state.getCurrentProgram()); + } + } + + options.setEliminateUnreachable(false); + + // HACK to turn off deadcode rule + // Really, it's abusing XML injection in setProtoEvalModel to + // add XML config that's not exposed through the interface. + String protoEvalModel = options.getProtoEvalModel(); + options.setProtoEvalModel(protoEvalModel + "\n" + + "\n" + + " " + SIMPLIFICATION_STYLE + "\n" + + " deadcode\n" + + " off\n" + + " \n" + + "" + protoEvalModel); + + return options; + } + + @Override + protected AddressCandidate storeDataCheck(Program program, PcodeOpAST pcodeOpAST) { + if (pcodeOpAST.getOpcode() != PcodeOp.COPY) + return null; + + if (getVerbose() > 0) { + printf("* data check: pcode store op @ %x : seq %d\n", + pcodeOpAST.getSeqnum().getTarget().getOffset(), + pcodeOpAST.getSeqnum().getOrder()); + } + + // Get input, make sure it's a valid address + Varnode dataToStore = pcodeOpAST.getInput(0); + if (!dataToStore.isConstant()) + return null; + + Address candidateAddr; + try { + candidateAddr = GhostringsUtil.addrFromConstant(program, dataToStore); + } catch (AddressOutOfBoundsException e) { + return null; + } + + // Check if the address is in .rodata + String blockName = GhostringsUtil.memBlockName(program, candidateAddr); + if (!STR_MEM_BLOCKS.contains(blockName)) + return null; + + // If output is a stack address, get the offset + Varnode storeLoc = pcodeOpAST.getOutput(); + if (!storeLoc.getAddress().isStackAddress()) { + return null; + } + + Long stackOffset = storeLoc.getAddress().getOffset(); + + if (getVerbose() > 0) { + printf("copy %s to addr. %s\n", candidateAddr.toString(), storeLoc.getAddress()); + } + + AddressCandidate result = new AddressCandidate(candidateAddr, stackOffset, pcodeOpAST); + return result; + } + + @Override + protected LengthCandidate storeLenCheck(Program program, PcodeOpAST pcodeOpAST) { + if (pcodeOpAST.getOpcode() != PcodeOp.COPY) + return null; + + if (getVerbose() > 0) { + printf("* length check: pcode store op @ %x : seq %d\n", + pcodeOpAST.getSeqnum().getTarget().getOffset(), + pcodeOpAST.getSeqnum().getOrder()); + } + + // Get input, make sure it's a constant + Varnode dataToStore = pcodeOpAST.getInput(0); + if (!dataToStore.isConstant()) + return null; + + long constantValue = dataToStore.getAddress().getOffset(); + + // Simple string length bounds check + if (constantValue < MIN_STR_LEN || constantValue > MAX_STR_LEN) { + return null; + } + + // If output is a stack address, get the offset + Varnode storeLoc = pcodeOpAST.getOutput(); + if (!storeLoc.getAddress().isStackAddress()) { + return null; + } + + Long stackOffset = storeLoc.getAddress().getOffset(); + + if (getVerbose() > 0) { + printf("copy constant 0x%x to addr. %s\n", + constantValue, + storeLoc.getAddress()); + } + + LengthCandidate result = new LengthCandidate((int) constantValue, stackOffset, pcodeOpAST); + return result; + } + +} diff --git a/ghidra_scripts/GoDynamicStringsSingle.java b/ghidra_scripts/GoDynamicStringsSingle.java new file mode 100644 index 0000000..a11b2b5 --- /dev/null +++ b/ghidra_scripts/GoDynamicStringsSingle.java @@ -0,0 +1,110 @@ +//Same as GoDynamicStrings, but doesn't use the parallel decompiler. +//Use this if the parallel decompiler is exhausting system memory. +// +//Find Go strings dynamically allocated on the stack (P-Code based). +//Clearing out all automatically defined strings in .rodata/.rdata first is recommended. +//The built-in ASCII Strings analysis can then be run again afterwards, +//with the option to clear existing strings disabled. +// +//This version uses the decompiler's "register" simplification style, +//which applies relatively few analysis rules. The resulting PCode output is +//more difficult to work with, but currently more reliable than the +//higher level version of the script. +//@author James Chambers +//@category Golang +//@keybinding +//@menupath +//@toolbar + +import java.util.Iterator; + +import ghidra.app.decompiler.DecompInterface; +import ghidra.app.decompiler.DecompileOptions; +import ghidra.app.decompiler.DecompileResults; +import ghidra.program.model.listing.Function; +import ghidra.program.model.pcode.HighFunction; +import ghostrings.GhostringsUtil; + +public class GoDynamicStringsSingle extends GoDynamicStrings { + + private DecompInterface decompIfc; + + private DecompInterface setUpDecompiler(String simplificationStyle) { + DecompInterface decompInterface = new DecompInterface(); + + DecompileOptions options = makeDecompileOptions(state); + + decompInterface.setOptions(options); + decompInterface.toggleCCode(false); + decompInterface.toggleSyntaxTree(true); + decompInterface.toggleParamMeasures(false); + decompInterface.setSimplificationStyle(simplificationStyle); + + return decompInterface; + } + + private HighFunction decompileFunction(Function func) { + HighFunction highFunc = null; + + try { + DecompileResults results = decompIfc.decompileFunction( + func, + decompIfc.getOptions().getDefaultTimeout(), + monitor); + + // Docs suggest calling this after every decompileFunction call + decompIfc.flushCache(); + + highFunc = results.getHighFunction(); + + String decompError = results.getErrorMessage(); + if (decompError != null && decompError.length() > 0) { + printf("Decompiler error for %s: %s\n", GhostringsUtil.funcNameAndAddr(func), + decompError.trim()); + } + + if (!results.decompileCompleted()) { + printf("Decompilation not completed for %s\n", GhostringsUtil.funcNameAndAddr(func)); + return null; + } + } catch (Exception e) { + println("Decompiler exception:"); + e.printStackTrace(); + } + + return highFunc; + } + + @Override + protected void analyzeFunctions(Iterator functions) throws Exception { + decompIfc = setUpDecompiler(getSimplificationStyle()); + + if (!decompIfc.openProgram(currentProgram)) { + println("Decompiler could not open program"); + final String lastMsg = decompIfc.getLastMessage(); + if (lastMsg != null) { + printf("Decompiler last message: %s\n", lastMsg); + } + decompIfc.stopProcess(); + return; + } + + long progress = 0; + + while (functions.hasNext() && !monitor.isCancelled()) { + Function func = functions.next(); + + monitor.setMessage("Decompiling " + GhostringsUtil.getFuncName(func)); + + HighFunction highFunc = decompileFunction(func); + if (highFunc != null) { + detectFunctionStrings(highFunc); + } + + monitor.setProgress(++progress); + } + + decompIfc.stopProcess(); + } + +} diff --git a/ghidra_scripts/GoKnownStrings.java b/ghidra_scripts/GoKnownStrings.java new file mode 100644 index 0000000..49eb2bf --- /dev/null +++ b/ghidra_scripts/GoKnownStrings.java @@ -0,0 +1,317 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +//Searches for standard unique strings and defines them. +//@author James Chambers +//@category Golang +//@keybinding +//@menupath +//@toolbar + +import java.util.ArrayList; +import java.util.List; + +import ghidra.app.script.GhidraScript; +import ghidra.program.model.address.Address; +import ghidra.program.model.listing.Data; +import ghidra.program.model.symbol.Symbol; +import ghidra.program.model.util.CodeUnitInsertionException; +import ghidra.util.StringUtilities; + +public class GoKnownStrings extends GhidraScript { + + private final static class KnownString { + final String name; + final String value; + + public KnownString(String name, String value) { + this.name = name; + this.value = value; + } + } + + private static final List KNOWN_STRINGS; + static { + KNOWN_STRINGS = new ArrayList<>(); + + // This 200 byte string from strconv/itoa.go is often near the end of go.string. + KNOWN_STRINGS.add(new KnownString( + "strconv/itoa.go:smallsString", + "00010203040506070809" + + "10111213141516171819" + + "20212223242526272829" + + "30313233343536373839" + + "40414243444546474849" + + "50515253545556575859" + + "60616263646566676869" + + "70717273747576777879" + + "80818283848586878889" + + "90919293949596979899" + )); + + // Also from strconv/itoa.go; not as unique + KNOWN_STRINGS.add(new KnownString( + "strconv/itoa.go:digits", + "0123456789abcdefghijklmnopqrstuvwxyz" + )); + + // leftcheats cutoff strings + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_22", + "2384185791015625" + )); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_23", + "11920928955078125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_24", + "59604644775390625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_25", + "298023223876953125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_26", + "1490116119384765625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_27", + "7450580596923828125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_28", + "37252902984619140625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_29", + "186264514923095703125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_30", + "931322574615478515625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_31", + "4656612873077392578125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_32", + "23283064365386962890625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_33", + "116415321826934814453125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_34", + "582076609134674072265625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_35", + "2910383045673370361328125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_36", + "14551915228366851806640625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_37", + "72759576141834259033203125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_38", + "363797880709171295166015625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_39", + "1818989403545856475830078125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_40", + "9094947017729282379150390625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_41", + "45474735088646411895751953125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_42", + "227373675443232059478759765625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_43", + "1136868377216160297393798828125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_44", + "5684341886080801486968994140625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_45", + "28421709430404007434844970703125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_46", + "142108547152020037174224853515625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_47", + "710542735760100185871124267578125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_48", + "3552713678800500929355621337890625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_49", + "17763568394002504646778106689453125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_50", + "88817841970012523233890533447265625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_51", + "444089209850062616169452667236328125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_52", + "2220446049250313080847263336181640625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_53", + "11102230246251565404236316680908203125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_54", + "55511151231257827021181583404541015625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_55", + "277555756156289135105907917022705078125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_56", + "1387778780781445675529539585113525390625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_57", + "6938893903907228377647697925567626953125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_58", + "34694469519536141888238489627838134765625")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_59", + "173472347597680709441192448139190673828125")); + + KNOWN_STRINGS.add(new KnownString( + "strconv/decimal.go:leftcheats_60", + "867361737988403547205962240695953369140625")); + } + + private final boolean verbose = false; + private final String printfPrefix = getScriptName().replace("%", "%%") + "> "; + + /** Make printf log prefix consistent with println */ + @Override + public void printf(String message, Object... args) { + super.printf(printfPrefix + message, args); + } + + private void printStringData(Data data) { + final String strData = (String) data.getValue(); + printf("%s, %d:\t\"%s\"\n", + data.getAddress(), + data.getLength(), + StringUtilities.convertControlCharsToEscapeSequences(strData)); + } + + /** + * Find string data after a start address and define it. Clears any conflicting + * data. + */ + private Data findAndDefineString(Address startAddr, String target) { + Address result = findBytes(startAddr, target); + if (result == null) { + if (verbose) { + println("Target string not found"); + } + return null; + } + + Data conflict = getDataAt(result); + if (conflict != null && + conflict.hasStringValue() && + target.equals(conflict.getValue())) { + // Already defined + return null; + } + + if (verbose) { + printf("Found target string @ %s\n", result); + } + + // Clear all conflicting data defined within the string + Address endAddr = result.add(target.length()); + try { + while (conflict != null && conflict.getAddress().compareTo(result) > -1) { + removeData(conflict); + conflict = getDataBefore(endAddr); + } + } catch (Exception e) { + // TODO Auto-generated catch block + e.printStackTrace(); + return null; + } + + try { + return createAsciiString(result, target.length()); + } catch (CodeUnitInsertionException e) { + // TODO Auto-generated catch block + e.printStackTrace(); + return null; + } + } + + @Override + protected void run() throws Exception { + List results = getSymbols("go.string.*", null); + if (results.size() != 1) { + final String msg = "Want a single go.string.* symbol, found " + results.size(); + println(msg); + popup(msg); + return; + } + + Symbol goStringsBlob = results.get(0); + Address blobAddr = goStringsBlob.getAddress(); + println("go.string.* @ " + blobAddr); + + for (KnownString knownString : KNOWN_STRINGS) { + Data strData = findAndDefineString(blobAddr, knownString.value); + if (strData != null) { + println("Found and defined " + knownString.name); + printStringData(strData); + } + } + } +} diff --git a/ghidra_scripts/GoStringFiller.java b/ghidra_scripts/GoStringFiller.java new file mode 100644 index 0000000..787c14b --- /dev/null +++ b/ghidra_scripts/GoStringFiller.java @@ -0,0 +1,382 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +//Fill in undefined strings based on the fact that they are defined in order of increasing length. +//For a stripped binary, one should first manually create the go.string.* label at the likely start location. +//@author James Chambers +//@category Golang +//@keybinding +//@menupath +//@toolbar + +import java.util.ArrayList; +import java.util.Arrays; +import java.util.List; + +import ghidra.app.script.GhidraScript; +import ghidra.program.model.address.Address; +import ghidra.program.model.data.DataType; +import ghidra.program.model.data.Undefined; +import ghidra.program.model.listing.Data; +import ghidra.program.model.symbol.Symbol; +import ghidra.program.model.util.CodeUnitInsertionException; +import ghidra.util.StringUtilities; + +public class GoStringFiller extends GhidraScript { + + private final boolean verbose = false; + private final String printfPrefix = getScriptName().replace("%", "%%") + "> "; + + private boolean allowFalsePositives = false; + private boolean autoClearShortStrings = false; + + private static long calcGapLength(Data left, Data right) { + return right.getAddress().getOffset() - (left.getAddress().getOffset() + left.getLength()); + } + + /** Make printf log prefix consistent with println */ + @Override + public void printf(String message, Object... args) { + super.printf(printfPrefix + message, args); + } + + private void fillRange(Address start, Address end, int length) { + // start addr must be less than end addr + if (start.compareTo(end) >= 0) + return; + + Address curAddr = start; + + while (curAddr.getOffset() < end.getOffset()) { + Data data = getDataAt(curAddr); + if (data == null) { + try { + String newStr = (String) createAsciiString(curAddr, length).getValue(); + printf("defined @ %s: \"%s\"\n", + curAddr.toString(), + StringUtilities.convertControlCharsToEscapeSequences(newStr)); + } catch (CodeUnitInsertionException e) { + println(e.getMessage()); + } + } + + curAddr = curAddr.add(length); + } + } + + private void fillCount(Address start, int length, int count) { + if (count == 0 || length == 0) { + throw new IllegalArgumentException(); + } + + Address end = start.add(count * length); + fillRange(start, end, length); + } + + /** + * Check if a gap between defined strings can be filled with strings of all the + * same length. + * + * NOTE: Allows false positives if there are strings of different lengths inside + * the gap, not just strings of all the same length. See + * {@link #findSplitLengths}. + * + * @param dataAt String data on the left + * @param dataAfter String data on the right + * @return True if it fills the gap with defined strings, false if not. + */ + private boolean findUniqueDivisor(Data dataAt, Data dataAfter) { + long gapLen = calcGapLength(dataAt, dataAfter); + + if (gapLen <= 0) { + // No gap + return false; + } + + if (verbose) { + printf("gap of %d between %s and %s\n", + gapLen, + dataAt.getAddress(), + dataAfter.getAddress()); + } + + boolean success = false; + int uniqueDiv = 0; + int rangeMin = dataAt.getLength(); + int rangeMax = dataAfter.getLength(); + + for (int testDiv = rangeMin; testDiv <= rangeMax; testDiv++) { + if (gapLen % testDiv == 0) { + if (uniqueDiv != 0) { + if (verbose) { + println("Couldn't pick unique divisor"); + } + success = false; + break; + } + uniqueDiv = testDiv; + success = true; + } + } + + if (success) { + if (verbose) { + printf("Unique divisor %d can make %d strings\n", uniqueDiv, gapLen / uniqueDiv); + } + Address startAt = dataAt.getAddress().add(dataAt.getLength()); + fillRange(startAt, dataAfter.getAddress(), uniqueDiv); + } + + return success; + } + + private List> splitLengthCandidates(int x, int y, long gapLen) { + List> candidates = new ArrayList<>(); + + // Special case if left/right length are the same + if (x == y) { + if (gapLen % x == 0) { + candidates.add(Arrays.asList((int) (gapLen / x), 0)); + } + return candidates; + } + + long max_count_y = Math.floorDiv(gapLen, y); + for (long count_y = max_count_y; count_y >= 0; count_y--) { + long remainder = gapLen - y * count_y; + if (remainder % x == 0) { + long count_x = remainder / x; + candidates.add(Arrays.asList((int) count_x, (int) count_y)); + } + } + + return candidates; + } + + /** + * Gap could have strings of different lengths in it. There could be multiple + * possibilities for a combination of lengths, or just one possibility. If there + * is a unique combination of lengths, this method will define strings based on + * those lengths and return true. Otherwise, it returns false. + * + * NOTE: This currently only handles up to two different lengths of strings in + * the gap. Need to handle more than two lengths at a time to ensure there are + * no alternate possibilities when the difference between leftLen and rightLen + * is greater than 1. + * + * For example, between 1 and 2 length strings, a gap of size 3 could be: + * [1, {1, 1, 1}, 2] + * or + * [1, {1, 2}, 2] + * + * There can also be unique combinations, such as: + * [3, (gapLen=7), 4] must be [3, {3, 4}, 4] + * + * @param left String data on the left + * @param right String data on the right + * @return True if a unique combination of lengths was discovered, false if not. + */ + private boolean findSplitLengths(Data left, Data right) { + long gapLen = calcGapLength(left, right); + + if (gapLen <= 0) { + // No gap + return false; + } + + List> candidates = splitLengthCandidates( + left.getLength(), right.getLength(), gapLen); + + if (candidates.size() != 1) { + // No unique result + return false; + } + + List counts = candidates.get(0); + int count_x = counts.get(0); + int count_y = counts.get(1); + + Address startLeft = left.getAddress().add(left.getLength()); + Address startRight = startLeft.add(count_x * left.getLength()); + + if (count_x > 0) { + fillCount(startLeft, left.getLength(), count_x); + } + + if (count_y > 0) { + fillCount(startRight, right.getLength(), count_y); + } + + return true; + } + + /** + * Minimum size of two strings in a gap is left_len*2. If the gap length is less + * than that (as well as the length of the next string), it must be one string. + * + * @param left String data on the left + * @param right String data on the right + * @return True if it fills the gap with defined strings, false if not. + */ + private boolean findOneIntermediary(Data left, Data right) { + long gapLen = calcGapLength(left, right); + + if (gapLen <= 0) { + return false; + } + + if (gapLen < (left.getLength() * 2) && gapLen <= right.getLength()) { + Address startAddr = left.getAddress().add(left.getLength()); + fillRange(startAddr, right.getAddress(), (int) gapLen); + return true; + } + + return false; + } + + /** + * Should be able to identify two of the smallest possible pairs of strings: two + * leftLen size strings, or a leftLen and leftLen+1 size string. The rightLen + * must be smaller than the gap size, or else there could also be a single + * string that fills the entire gap. + * + * @param left String data on the left + * @param right String data on the right + * @return True if it fills the gap with defined strings, false if not. + */ + private boolean findTwoIntermediaries(Data left, Data right) { + long gapLen = calcGapLength(left, right); + + if (gapLen <= 0) { + return false; + } + + int leftLen = left.getLength(); + int rightLen = right.getLength(); + + if (leftLen > 1 && gapLen > rightLen) { + if (gapLen == leftLen * 2) { + // it's 2 leftLen strings + Address startAddr = left.getAddress().add(leftLen); + fillCount(startAddr, leftLen, 2); + return true; + } else if (gapLen == leftLen * 2 + 1) { + // it's a leftLen string, then a leftLen+1 string + Address startAddr = left.getAddress().add(leftLen); + fillCount(startAddr, leftLen, 1); + fillCount(startAddr.add(leftLen), leftLen + 1, 1); + return true; + } + } + + return false; + } + + private void printStringData(Data data) { + final String strData = (String) data.getValue(); + printf("%s, %d:\t\"%s\"\n", + data.getAddress(), + data.getLength(), + StringUtilities.convertControlCharsToEscapeSequences(strData)); + } + + @Override + protected void run() throws Exception { + List results = getSymbols("go.string.*", null); + if (results.size() != 1) { + final String msg = "Want a single go.string.* symbol, found " + results.size(); + println(msg); + popup(msg); + return; + } + + autoClearShortStrings = askYesNo( + "Automatically clear short strings?", + "Automatically clear a defined string if it violates the\n" + + "ascending length order of go.string.*?"); + + allowFalsePositives = askYesNo( + "Allow false positives?", + "Assume gaps in go.string.* are filled with strings of\n" + + "all the same length (if unique length values can't be determined),\n" + + "which could result in false positives?"); + + Symbol goStringsBlob = results.get(0); + println("go.string.* @ " + goStringsBlob.getAddress()); + + Address curAddr = goStringsBlob.getAddress(); + while (!monitor.isCancelled()) { + Data dataAt = getDataAt(curAddr); + Data dataAfter = getDataAfter(curAddr); + + if (dataAfter == null) { + println("no more data definitions"); + break; + } else if (!dataAfter.hasStringValue()) { + DataType dType = dataAfter.getDataType(); + if (Undefined.isUndefined(dType)) { + removeData(dataAfter); + // Restart the loop + continue; + } + println("reached non-string data @ " + dataAfter.getAddress()); + // TODO go.func.* might also be a good marker for the end of go.string.* + break; + } else if (dataAt != null && dataAt.hasStringValue()) { + if (verbose) { + printStringData(dataAt); + } + + if (dataAfter.getLength() < dataAt.getLength()) { + // Shouldn't happen within the blob; usually a string declared + // with too short a length. Easy to manually clear and re-run. + println("reached smaller string @ " + dataAfter.getAddress()); + if (!verbose) + printStringData(dataAfter); + if (autoClearShortStrings) { + removeData(dataAfter); + continue; + } + break; + } + + // Check if a group of strings can be found based on gap between defined strings + boolean success = false; + if (dataAfter.getLength() - dataAt.getLength() <= 1) { + success = findSplitLengths(dataAt, dataAfter); + } + + if (!success) { + success = findOneIntermediary(dataAt, dataAfter); + } + + if (!success) { + // Not tested as much + success = findTwoIntermediaries(dataAt, dataAfter); + } + + if (!success && allowFalsePositives) { + // Currently assumes the gap is filled with strings of all the same length, + // but there could be strings of different lengths in between. + success = findUniqueDivisor(dataAt, dataAfter); + } + } + + curAddr = dataAfter.getAddress(); + } + } +} diff --git a/ghidra_scripts/PrintHighPCode.java b/ghidra_scripts/PrintHighPCode.java new file mode 100644 index 0000000..fbb2f52 --- /dev/null +++ b/ghidra_scripts/PrintHighPCode.java @@ -0,0 +1,178 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +//Print high P-Code for currently selected function, with simplification style selector +//@author James Chambers +//@category PCode +//@keybinding +//@menupath +//@toolbar + +import java.io.File; +import java.util.Arrays; +import java.util.Iterator; +import java.util.List; + +import ghidra.app.decompiler.DecompInterface; +import ghidra.app.decompiler.DecompileOptions; +import ghidra.app.decompiler.DecompileResults; +import ghidra.app.script.GhidraScript; +import ghidra.framework.options.ToolOptions; +import ghidra.framework.plugintool.PluginTool; +import ghidra.framework.plugintool.util.OptionsService; +import ghidra.program.model.listing.Function; +import ghidra.program.model.pcode.HighFunction; +import ghidra.program.model.pcode.PcodeOpAST; +import ghidra.util.exception.CancelledException; +import ghostrings.GhostringsUtil; + +public class PrintHighPCode extends GhidraScript { + // Groups / root actions: firstpass, register, paramid, normalize, + // jumptable, decompile + private static final String[] SIMPLIFICATION_STYLES = new String[] { + "decompile", + "jumptable", + "normalize", + "paramid", + "register", + "firstpass" + }; + + private DecompInterface decompIfc; + + private DecompInterface setUpDecompiler(String simplificationStyle) { + DecompInterface decompInterface = new DecompInterface(); + + DecompileOptions options = new DecompileOptions(); + + PluginTool tool = state.getTool(); + if (tool != null) { + OptionsService service = tool.getService(OptionsService.class); + if (service != null) { + ToolOptions opt = service.getOptions("Decompiler"); + options.grabFromToolAndProgram(null, opt, currentProgram); + } + } + + options.setEliminateUnreachable(false); + + decompInterface.setOptions(options); + decompInterface.toggleCCode(false); + decompInterface.toggleSyntaxTree(true); + decompInterface.toggleParamMeasures(false); + decompInterface.setSimplificationStyle(simplificationStyle); + + return decompInterface; + } + + private HighFunction decompileFunction(Function func) { + HighFunction highFunc = null; + + try { + DecompileResults results = decompIfc.decompileFunction( + func, + decompIfc.getOptions().getDefaultTimeout(), + monitor); + + // Docs suggest calling this after every decompileFunction call + decompIfc.flushCache(); + + highFunc = results.getHighFunction(); + + String decompError = results.getErrorMessage(); + if (decompError != null && decompError.length() > 0) { + printf("Decompiler error for %s: %s\n", GhostringsUtil.funcNameAndAddr(func), + decompError.trim()); + } + + if (!results.decompileCompleted()) { + printf("Decompilation not completed for %s\n", GhostringsUtil.funcNameAndAddr(func)); + return null; + } + } catch (Exception e) { + println("Decompiler exception:"); + e.printStackTrace(); + } + + return highFunc; + } + + private String askStyleChoice() throws CancelledException { + final List choices = Arrays.asList(SIMPLIFICATION_STYLES); + return askChoice("PCode Dump", "Select simplification style", choices, + SIMPLIFICATION_STYLES[0]); + } + + @Override + protected void run() throws Exception { + // Check currently selected function + Function func = getFunctionContaining(currentAddress); + if (func == null) { + final String msg = "No function selected"; + println(msg); + popup(msg); + return; + } + + final String styleChoice = askStyleChoice(); + decompIfc = setUpDecompiler(styleChoice); + + if (!decompIfc.openProgram(currentProgram)) { + println("Decompiler could not open program"); + final String lastMsg = decompIfc.getLastMessage(); + if (lastMsg != null) { + printf("Decompiler last message: %s\n", lastMsg); + } + decompIfc.stopProcess(); + return; + } + + final boolean xmlDumpEnabled = askYesNo("Save XML dump?", + "Save decompiler IPC XML dump for debugging?"); + if (xmlDumpEnabled) { + try { + final File debugDump = askFile("Decompiler IPC XML Dump", "Save"); + decompIfc.enableDebug(debugDump); + printf("Saving decompiler IPC XML dump to %s\n", debugDump.getPath()); + } catch (CancelledException e) { + println("XML dump save cancelled"); + } + } + + printf("PCode for function %s (simplification style: %s)\n", + GhostringsUtil.funcNameAndAddr(func), + styleChoice); + + HighFunction highFunc = decompileFunction(func); + if (highFunc == null) { + println("Failed to decompile function"); + decompIfc.stopProcess(); + return; + } + + Iterator ops = highFunc.getPcodeOps(); + while (ops.hasNext() && !monitor.isCancelled()) { + PcodeOpAST pcodeOpAST = ops.next(); + + printf("0x%x:0x%02x\t%s\n", + pcodeOpAST.getSeqnum().getTarget().getOffset(), + pcodeOpAST.getSeqnum().getTime(), pcodeOpAST.toString()); + } + + decompIfc.stopProcess(); + } +} diff --git a/ghidra_scripts/README.txt b/ghidra_scripts/README.txt new file mode 100644 index 0000000..9e408f4 --- /dev/null +++ b/ghidra_scripts/README.txt @@ -0,0 +1 @@ +Java source directory to hold module-specific Ghidra scripts. diff --git a/lib/README.txt b/lib/README.txt new file mode 100644 index 0000000..528dbc6 --- /dev/null +++ b/lib/README.txt @@ -0,0 +1,3 @@ +The "lib" directory is intended to hold Jar files which this module is dependent upon. Jar files +may be placed in this directory manually, or automatically by maven via the dependencies block +of this module's build.gradle file. \ No newline at end of file diff --git a/src/main/help/help/TOC_Source.xml b/src/main/help/help/TOC_Source.xml new file mode 100644 index 0000000..a34f62e --- /dev/null +++ b/src/main/help/help/TOC_Source.xml @@ -0,0 +1,57 @@ + + + + + + + diff --git a/src/main/help/help/shared/Frontpage.css b/src/main/help/help/shared/Frontpage.css new file mode 100644 index 0000000..b847166 --- /dev/null +++ b/src/main/help/help/shared/Frontpage.css @@ -0,0 +1,64 @@ +/* ### + * 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. + */ +/* + WARNING! + This file is copied to all help directories. If you change this file, you must copy it + to each src/main/help/help/shared directory. + + + Java Help Note: JavaHelp does not accept sizes (like in 'margin-top') in anything but + px (pixel) or with no type marking. + +*/ + +body { margin-bottom: 50px; margin-left: 10px; margin-right: 10px; margin-top: 10px; } /* some padding to improve readability */ +li { font-family:times new roman; font-size:14pt; } +h1 { color:#000080; font-family:times new roman; font-size:36pt; font-style:italic; font-weight:bold; text-align:center; } +h2 { margin: 10px; margin-top: 20px; color:#984c4c; font-family:times new roman; font-size:18pt; font-weight:bold; } +h3 { margin-left: 10px; margin-top: 20px; color:#0000ff; font-family:times new roman; `font-size:14pt; font-weight:bold; } +h4 { margin-left: 10px; margin-top: 20px; font-family:times new roman; font-size:14pt; font-style:italic; } + +/* + P tag code. Most of the help files nest P tags inside of blockquote tags (the was the + way it had been done in the beginning). The net effect is that the text is indented. In + modern HTML we would use CSS to do this. We need to support the Ghidra P tags, nested in + blockquote tags, as well as naked P tags. The following two lines accomplish this. Note + that the 'blockquote p' definition will inherit from the first 'p' definition. +*/ +p { margin-left: 40px; font-family:times new roman; font-size:14pt; } +blockquote p { margin-left: 10px; } + +p.providedbyplugin { color:#7f7f7f; margin-left: 10px; font-size:14pt; margin-top:100px } +p.ProvidedByPlugin { color:#7f7f7f; margin-left: 10px; font-size:14pt; margin-top:100px } +p.relatedtopic { color:#800080; margin-left: 10px; font-size:14pt; } +p.RelatedTopic { color:#800080; margin-left: 10px; font-size:14pt; } + +/* + We wish for a tables to have space between it and the preceding element, so that text + is not too close to the top of the table. Also, nest the table a bit so that it is clear + the table relates to the preceding text. +*/ +table { margin-left: 20px; margin-top: 10px; width: 80%;} +td { font-family:times new roman; font-size:14pt; vertical-align: top; } +th { font-family:times new roman; font-size:14pt; font-weight:bold; background-color: #EDF3FE; } + +/* + Code-like formatting for things such as file system paths and proper names of classes, + methods, etc. To apply this to a file path, use this syntax: + ... +*/ +code { color: black; font-weight: bold; font-family: courier new, monospace; font-size: 14pt; white-space: nowrap; } +code.path { color: #4682B4; font-weight: bold; font-family: courier new, monospace; font-size: 14pt; white-space: nowrap; } diff --git a/src/main/help/help/topics/ghostrings/help.html b/src/main/help/help/topics/ghostrings/help.html new file mode 100644 index 0000000..8f858d2 --- /dev/null +++ b/src/main/help/help/topics/ghostrings/help.html @@ -0,0 +1,23 @@ + + + + + + + + + + + Skeleton Help File for a Module + + + + +

Skeleton Help File for a Module

+ +

This is a simple skeleton help topic. For a better description of what should and should not + go in here, see the "sample" Ghidra extension in the Extensions/Ghidra directory, or see your + favorite help topic. In general, language modules do not have their own help topics.

+ + diff --git a/src/main/java/ghostrings/AddressCandidate.java b/src/main/java/ghostrings/AddressCandidate.java new file mode 100644 index 0000000..a1cc2d5 --- /dev/null +++ b/src/main/java/ghostrings/AddressCandidate.java @@ -0,0 +1,57 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +package ghostrings; + +import ghidra.program.model.address.Address; +import ghidra.program.model.pcode.PcodeOpAST; + +public final class AddressCandidate { + private Address stringAddr; + private PcodeOpAST pcodeOp; + private long stackOffset; + + public AddressCandidate(Address stringAddr, long stackOffset, PcodeOpAST pcodeOp) { + this.setStringAddr(stringAddr); + this.setStackOffset(stackOffset); + this.setPcodeOp(pcodeOp); + } + + public Address getStringAddr() { + return stringAddr; + } + + public void setStringAddr(Address stringAddr) { + this.stringAddr = stringAddr; + } + + public PcodeOpAST getPcodeOp() { + return pcodeOp; + } + + public void setPcodeOp(PcodeOpAST pcodeOp) { + this.pcodeOp = pcodeOp; + } + + public long getStackOffset() { + return stackOffset; + } + + public void setStackOffset(long stackOffset) { + this.stackOffset = stackOffset; + } +} \ No newline at end of file diff --git a/src/main/java/ghostrings/GhostringsUtil.java b/src/main/java/ghostrings/GhostringsUtil.java new file mode 100644 index 0000000..3a11fe9 --- /dev/null +++ b/src/main/java/ghostrings/GhostringsUtil.java @@ -0,0 +1,301 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +package ghostrings; + +import java.util.HashSet; +import java.util.Set; + +import ghidra.app.script.GhidraScript; +import ghidra.program.model.address.Address; +import ghidra.program.model.address.AddressFactory; +import ghidra.program.model.address.AddressOutOfBoundsException; +import ghidra.program.model.address.AddressOverflowException; +import ghidra.program.model.address.AddressSpace; +import ghidra.program.model.data.DataType; +import ghidra.program.model.data.Undefined; +import ghidra.program.model.lang.Register; +import ghidra.program.model.listing.Data; +import ghidra.program.model.listing.Function; +import ghidra.program.model.listing.Program; +import ghidra.program.model.mem.MemoryAccessException; +import ghidra.program.model.mem.MemoryBlock; +import ghidra.program.model.pcode.PcodeOp; +import ghidra.program.model.pcode.Varnode; +import ghidra.util.ascii.AsciiCharSetRecognizer; +import ghostrings.exceptions.DuplicateDataException; +import ghostrings.exceptions.UnhandledOpArgsException; +import ghostrings.exceptions.UnhandledOpTypeException; + +public class GhostringsUtil { + + private static final Set SP_REG_NAMES; + static { + SP_REG_NAMES = new HashSet<>(); + // Always use upper case + SP_REG_NAMES.add("SP"); + SP_REG_NAMES.add("ESP"); + SP_REG_NAMES.add("RSP"); + } + + private GhostringsUtil() { + // No instantiation + } + + public static String getFuncName(Function func) { + if (func.getName() != null) + return func.getName(); + return "(undefined)"; + } + + public static String funcNameAndAddr(Function func) { + return String.format( + "%s @ %s", + getFuncName(func), + func.getEntryPoint().toString()); + } + + public static String memBlockName(Program program, Address addr) { + MemoryBlock block = program.getMemory().getBlock(addr); + if (block == null) { + return null; + } + return block.getName(); + } + + /** + * Create a memory address from a constant value varnode + * + * @param program Program to create an address for + * @param varnode Constant value varnode + * @return Address in the program's default address space, with the constant + * value as its offset + * @throws AddressOutOfBoundsException + */ + public static Address addrFromConstant(Program program, Varnode varnode) throws AddressOutOfBoundsException { + if (!varnode.isConstant()) { + throw new IllegalArgumentException(); + } + + // The constant value is stored as its "address" offset + long constVal = varnode.getAddress().getOffset(); + + // Use the value as an address in the program's default address space + AddressSpace defaultAddrSpace = program.getAddressFactory().getDefaultAddressSpace(); + return defaultAddrSpace.getAddress(constVal); + } + + /** Check if register is a stack register */ + public static boolean isStackRegister(Register reg) { + // "getTypeFlags() & Register.TYPE_SP" seems right but doesn't work for RSP + final String regName = reg.getName(); + if (regName == null) { + return false; + } + + return SP_REG_NAMES.contains(regName.toUpperCase()); + } + + /** Check if varnode refers to a stack register */ + public static boolean isStackRegister(Program program, Varnode varnode) { + Register reg = program.getRegister(varnode); + if (reg != null && isStackRegister(reg)) { + return true; + } + return false; + } + + /** Check if Pcode op has the stack register as an input */ + public static boolean hasStackInput(Program program, PcodeOp op) { + for (Varnode varnode : op.getInputs()) { + if (isStackRegister(program, varnode)) { + return true; + } + } + return false; + } + + /** + * Get stack offset from INT_ADD op, or null if a stack offset can't be determined. + * @param program + * @param op + * @return Stack offset long or null + * @throws UnhandledOpArgsException + */ + public static Long intAddStackOffset(Program program, PcodeOp op) throws UnhandledOpArgsException { + if (op.getOpcode() != PcodeOp.INT_ADD) { + throw new IllegalArgumentException("Wrong op type"); + } + + // input 0: should be an SP register + Varnode regVarnode = op.getInput(0); + if (!isStackRegister(program, regVarnode)) { + return null; + } + + // input 1: constant is the offset from SP + Varnode offsetVarnode = op.getInput(1); + if (!offsetVarnode.isConstant()) { + // TODO: Input could be a register, which might have a defining op with a constant + throw new UnhandledOpArgsException("Unhandled INT_ADD args"); + } + + return offsetVarnode.getOffset(); + } + + /** + * Check if output varnode is based on a stack register offset. Returns SP + * offset or null. + * + * @throws UnhandledOpTypeException Op with stack register input has no handler + * @throws UnhandledOpArgsException Unhandled inputs for op with stack input + */ + public static Long outputStackOffset(Program program, Varnode storeLoc) + throws UnhandledOpTypeException, UnhandledOpArgsException { + PcodeOp defineOp = storeLoc.getDef(); + if (defineOp == null) + return null; + + // So far, it's always been INT_ADD + switch (defineOp.getOpcode()) { + case PcodeOp.INT_ADD: + return intAddStackOffset(program, defineOp); + } + + // The only use for this is to detect unhandled cases + if (hasStackInput(program, defineOp)) { + throw new UnhandledOpTypeException("Unhandled op type"); + } + + return null; + } + + /** Get the source/dest address from a LOAD/STORE op */ + public static Address getLoadStoreAddr(PcodeOp op, AddressFactory addrFactory) { + if (op.getOpcode() != PcodeOp.STORE && op.getOpcode() != PcodeOp.LOAD) + throw new IllegalArgumentException("Must be STORE or LOAD op"); + + int spaceId = (int) op.getInput(0).getOffset(); + long offset = op.getInput(1).getOffset(); + + // TODO: "If the wordsize attribute of the space given by the ID is bigger than + // one, the offset into the space obtained from input1 must be multiplied by + // this value in order to obtain the correct byte offset into the space." + + Address loadAddr = addrFactory.getAddress(spaceId, offset); + return loadAddr; + } + + /** + * Check if a region of memory contains only ASCII characters. + * + * @param program Program + * @param stringAddr Address to begin checking for ASCII characters + * @param stringLen Length of the string to check + * @return String data if all bytes at the address are ASCII characters, or null + * if there are rejected characters + */ + public static String checkForString(Program program, Address stringAddr, int stringLen) { + if (stringLen <= 0) { + throw new IllegalArgumentException("String length must be greater than 0"); + } + + if (!stringAddr.isLoadedMemoryAddress()) { + return null; + } + + AsciiCharSetRecognizer asciiRec = new AsciiCharSetRecognizer(); + + StringBuilder sb = new StringBuilder(); + try { + for (long i = 0; i < stringLen; i++) { + Byte curByte = program.getMemory().getByte(stringAddr); + + // TODO Detect non-ASCII strings + // See ghidra.util.ascii and StringUtilities for useful methods + if (!asciiRec.contains(curByte)) + return null; + + sb.append((char) (curByte & 0xff)); + + stringAddr = stringAddr.addNoWrap(1); + } + } catch (MemoryAccessException | AddressOverflowException e) { + // TODO Auto-generated catch block + // e.printStackTrace(); + return null; + } + + return sb.toString(); + } + + /** + * Try to define a string, with some checks for conflicting data. + * @param script Script instance for the program being analyzed + * @param stringAddr Address to create the string at + * @param checkString Expected string data to be defined + * @param verbose Log messages about conflicting data + * @return True if the string data is defined, false if not. + * @throws Exception + */ + public static boolean tryDefString(GhidraScript script, Address stringAddr, String checkString, int verbose) throws Exception { + // Check for conflicting data definition + final Data conflictData = script.getDataContaining(stringAddr); + if (conflictData != null) { + if (verbose > 0) + script.println("Conflicting data: " + conflictData.toString()); + + if (!conflictData.hasStringValue()) { + // If it's an "undefined" type entry just delete it + DataType dType = conflictData.getDataType(); + if (Undefined.isUndefined(dType)) { + if (verbose > 0) + script.println("Removing undefined data type"); + + script.removeData(conflictData); + } else { + if (verbose > 0) + script.println("Unhandled non-string conflicting data, skipping"); + return false; + } + } else { + // Handle conflicting string data + final String conflictString = (String) conflictData.getValue(); + final boolean sameStartAddr = stringAddr.equals(conflictData.getAddress()); + + if (sameStartAddr && checkString.equals(conflictString)) { + // TODO might be cleaner as a separate "check string already exists" method + throw new DuplicateDataException("Found already defined string"); + } else if (sameStartAddr && checkString.length() > conflictString.length()) { + // Existing string is smaller + if (verbose > 0) + script.println("Taking larger new value"); + + script.removeDataAt(stringAddr); + } else { + // Existing data is larger or has a different start address: + // might be bad glob, or other false positive + return false; + } + } + } + + script.createAsciiString(stringAddr, checkString.length()); + return true; + } + +} diff --git a/src/main/java/ghostrings/LengthCandidate.java b/src/main/java/ghostrings/LengthCandidate.java new file mode 100644 index 0000000..d40edd3 --- /dev/null +++ b/src/main/java/ghostrings/LengthCandidate.java @@ -0,0 +1,56 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +package ghostrings; + +import ghidra.program.model.pcode.PcodeOpAST; + +public final class LengthCandidate { + private int stringLength; + private PcodeOpAST pcodeOp; + private long stackOffset; + + public LengthCandidate(int stringLength, long stackOffset, PcodeOpAST pcodeOp) { + this.setStringLength(stringLength); + this.setStackOffset(stackOffset); + this.setPcodeOp(pcodeOp); + } + + public int getStringLength() { + return stringLength; + } + + public void setStringLength(int stringLength) { + this.stringLength = stringLength; + } + + public PcodeOpAST getPcodeOp() { + return pcodeOp; + } + + public void setPcodeOp(PcodeOpAST pcodeOp) { + this.pcodeOp = pcodeOp; + } + + public long getStackOffset() { + return stackOffset; + } + + public void setStackOffset(long stackOffset) { + this.stackOffset = stackOffset; + } +} \ No newline at end of file diff --git a/src/main/java/ghostrings/exceptions/DuplicateDataException.java b/src/main/java/ghostrings/exceptions/DuplicateDataException.java new file mode 100644 index 0000000..b3b6c77 --- /dev/null +++ b/src/main/java/ghostrings/exceptions/DuplicateDataException.java @@ -0,0 +1,25 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +package ghostrings.exceptions; + +/** Attempted to define data (e.g., an ASCII string) that already exists. */ +public class DuplicateDataException extends Exception { + public DuplicateDataException(String errorMessage) { + super(errorMessage); + } +} diff --git a/src/main/java/ghostrings/exceptions/UnhandledOpArgsException.java b/src/main/java/ghostrings/exceptions/UnhandledOpArgsException.java new file mode 100644 index 0000000..61c941d --- /dev/null +++ b/src/main/java/ghostrings/exceptions/UnhandledOpArgsException.java @@ -0,0 +1,27 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +package ghostrings.exceptions; + +/** + * When there's no handler for certain types of inputs to a Pcode op. + */ +public class UnhandledOpArgsException extends Exception { + public UnhandledOpArgsException(String errorMessage) { + super(errorMessage); + } +} diff --git a/src/main/java/ghostrings/exceptions/UnhandledOpTypeException.java b/src/main/java/ghostrings/exceptions/UnhandledOpTypeException.java new file mode 100644 index 0000000..5ae537c --- /dev/null +++ b/src/main/java/ghostrings/exceptions/UnhandledOpTypeException.java @@ -0,0 +1,25 @@ +/* ### + * Ghostrings + * Copyright (C) 2022 NCC Group + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +package ghostrings.exceptions; + +/** When there's no handler for a Pcode Op type */ +public class UnhandledOpTypeException extends Exception { + public UnhandledOpTypeException(String errorMessage) { + super(errorMessage); + } +} diff --git a/src/main/resources/images/README.txt b/src/main/resources/images/README.txt new file mode 100644 index 0000000..f20ae77 --- /dev/null +++ b/src/main/resources/images/README.txt @@ -0,0 +1,2 @@ +The "src/resources/images" directory is intended to hold all image/icon files used by +this module. diff --git a/src/test/java/README.test.txt b/src/test/java/README.test.txt new file mode 100644 index 0000000..11b8a4a --- /dev/null +++ b/src/test/java/README.test.txt @@ -0,0 +1,2 @@ +The "test" directory is intended to hold unit test cases. The package structure within +this folder should correspond to that found in the "src" folder.