Create example

Author: JanWichelmann

.github/workflows/microwalk.yml

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+name: Build & Analyze with Microwalk
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+env:
+  script_directory: microwalk
+
+jobs:
+  build-analyze:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      
+      - name: Run Microwalk analysis
+        id: run_microwalk
+        uses: microwalk-project/microwalk-pin-action@v1
+        with:
+          script-directory: ${{ env.script_directory }}
+      
+      - name: Upload analysis result
+        uses: github/codeql-action/upload-sarif@v2
+        with:
+          sarif_file: ${{ github.workspace }}/${{ env.script_directory }}/results/report.sarif
+          checkout_path: ${{ github.workspace }}
+      
+      - name: Archive analysis artifacts
+        uses: actions/upload-artifact@v3
+        with:
+          name: leakage-analysis-results
+          path: ${{ github.workspace }}/${{ env.script_directory }}/results

LICENSE

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+MIT License
+
+Copyright (c) Institute for IT Security, University of Lübeck
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Makefile

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+.PHONY : clean
+
+CFLAGS=-O2 -fPIC -g
+LDFLAGS=-shared
+
+SOURCES=$(shell echo src/*.c)
+OBJECTS=$(SOURCES:.c=.o)
+
+TARGET=libexample.so
+
+all: $(TARGET)
+
+clean:
+	rm -f $(OBJECTS) $(TARGET)
+
+$(TARGET) : $(OBJECTS)
+	$(CC) $(CFLAGS) $(OBJECTS) -o $@ $(LDFLAGS)

README.md

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+# Microwalk Pin GitHub Workflow Example
+
+This repository features a simple example for running the Microwalk GitHub analysis workflow with C code.
+
+It makes use of [microwalk-pin-action](https://github.com/microwalk-project/microwalk-pin-action) to analyze the targets `microwalk/target-*.c` and generate a leakage report.
+
+The target code calls functions from our `libexample` library, as defined in the [src](src) folder. In the `master` branch, those are empty and thus constant-time. In the example pull request ["#1 Add leakage"](https://github.com/microwalk-project/example-c/pull/1) (for branch `add-leakage`), the functions are filled with leaking code, that is subsequently detected by the Microwalk analysis.
+
+The SARIF-formatted leakage report is sent back to GitHub and displayed both in the pull request UI (for everyone) and in the repository's "Security" tab (for users with write access only).

microwalk/.gitignore

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+*.dwarf
+*.map

microwalk/analyze.sh

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+#!/bin/bash
+
+set -e
+
+thisDir=$(pwd)
+repoRootDir=$(realpath $thisDir/..)
+resultsDir=$thisDir/results
+
+mkdir -p $resultsDir
+
+reports=""
+
+for target in $(find . -name "target-*.c" -print)
+do
+  targetName=$(basename -- ${target%.*})
+  
+  echo "Running target ${targetName}..."
+  
+  export TESTCASE_DIRECTORY=$thisDir/testcases/$targetName
+  export TARGET_NAME=$targetName
+  
+  mkdir -p $WORK_DIR/$targetName/work
+  mkdir -p $WORK_DIR/$targetName/persist
+  
+  cd $MICROWALK_PATH
+  time dotnet Microwalk.dll $thisDir/config.yml
+  
+  cd $CQR_GENERATOR_PATH
+  reportFile=$resultsDir/report-$targetName.sarif
+  dotnet CiReportGenerator.dll $WORK_DIR/$targetName/persist/results/call-stacks.json $targetName $reportFile sarif dwarf $thisDir $repoRootDir
+  
+  cd $thisDir
+  cp $WORK_DIR/$targetName/persist/results/call-stacks.txt $resultsDir/call-stacks-$targetName.txt
+  
+  reports="${reports} ${reportFile}"
+  
+  echo "Running target ${targetName} successful, generated report ${reportFile}"
+done
+
+echo "Merging report files..."
+cat $reports | jq -s '.[0].runs[0].results=([.[].runs[0].results]|flatten)|.[0]' > $resultsDir/report.sarif

microwalk/build.sh

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+#!/bin/bash
+
+thisDir=$(pwd)
+mainDir=$(realpath $thisDir/..)
+
+# Build library
+pushd $mainDir
+make -j all
+dwarfdump -l libexample.so >microwalk/libexample.so.dwarf
+popd
+
+# Generate MAP file for library
+pushd $MAP_GENERATOR_PATH
+dotnet MapFileGenerator.dll $mainDir/libexample.so $thisDir/libexample.map
+popd
+
+# Build targets
+for target in $(find . -name "target-*.c" -print)
+do
+  targetName=$(basename -- ${target%.*})
+  
+  gcc main.c $targetName.c -g -fno-inline -fno-split-stack -L "$mainDir" -lexample -I "$mainDir/src" -o $targetName
+  
+  pushd $MAP_GENERATOR_PATH
+  dotnet MapFileGenerator.dll $thisDir/$targetName $thisDir/$targetName.map
+  popd
+  
+  dwarfdump -l $targetName >$targetName.dwarf
+done

microwalk/config.yml

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+constants:
+  TARGET_PATH: $$CONFIG_PATH$$/$$$TARGET_NAME$$$
+  LIBRARY_PATH: $$CONFIG_PATH$$/../
+  WORK_DIR: $$$WORK_DIR$$$/$$$TARGET_NAME$$$
+---
+
+general:
+  logger:
+    log-level: warning
+    file: $$WORK_DIR$$/work/log.txt
+  monitor:
+    enable: true
+    sample-rate: 50
+   
+testcase:
+  module: load
+  module-options:
+    input-directory: $$$TESTCASE_DIRECTORY$$$
+
+trace:
+  module: pin
+  module-options:
+    output-directory: $$WORK_DIR$$/work/traces
+    pin-tool-path: $$$PINTOOL$$$
+    pin-path: $$$PIN_PATH$$$/pin
+    wrapper-path: $$TARGET_PATH$$
+    environment:
+      LD_LIBRARY_PATH: $$LIBRARY_PATH$$
+    images:
+      - $$TARGET_NAME$$
+      - libexample.so
+  options:
+    input-buffer-size: 4
+    
+preprocess:
+  module: pin
+  module-options:
+    output-directory: $$WORK_DIR$$/work/traces
+    store-traces: true
+    keep-raw-traces: false
+  options:
+    input-buffer-size: 2
+    max-parallel-threads: 4
+  
+analysis:
+  modules:
+    - module: control-flow-leakage
+      module-options:
+        output-directory: $$WORK_DIR$$/persist/results
+        map-files:
+          - $$TARGET_PATH$$.map
+          - libexample.map
+        dump-call-tree: false
+        include-testcases-in-call-stacks: false
+        
+  options:
+    input-buffer-size: 1
+    max-parallel-threads: 1

microwalk/main.c

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+#ifdef _GNU_SOURCE
+    #undef _GNU_SOURCE
+#endif
+
+#include <sys/resource.h>
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+
+
+// Performs target initialization steps.
+// This function is called once in the very beginning for the first testcase file, to make sure that the target is entirely loaded.
+// The call is included in the trace prefix.
+extern void InitTarget(FILE* input);
+
+// Executes the target function.
+// Do not use global variables, since the trace generator will reuse the instrumented version of this executable for several different inputs.
+extern void RunTarget(FILE* input);
+
+
+// Pin notification functions.
+// These functions (and their names) must not be optimized away by the compiler, so Pin can find and instrument them.
+// The return values reduce the probability that the compiler uses these function in other places as no-ops (Visual C++ did do this in some experiments).
+#pragma optimize("", off)
+int PinNotifyTestcaseStart(int t) { return t + 42; }
+int PinNotifyTestcaseEnd() { return 42; }
+int PinNotifyStackPointer(uint64_t spMin, uint64_t spMax) { return (int)(spMin + spMax + 42); }
+int PinNotifyAllocation(uint64_t address, uint64_t size) { return (int)(address + 23 * size); }
+#pragma optimize("", on)
+
+// Reads the stack pointer base value and transmits it to Pin.
+void ReadAndSendStackPointer()
+{
+    // There does not seem to be a reliable way to get the stack size, so we use an estimation
+    // Compiling with -fno-split-stack may be desired, to avoid surprises during analysis
+
+    // Take the current stack pointer as base value
+    uintptr_t stackBase;
+    asm("mov %%rsp, %0" : "=r"(stackBase));
+
+    // Get full stack size
+    struct rlimit stackLimit;
+    if(getrlimit(RLIMIT_STACK, &stackLimit) != 0)
+    {
+        char errBuffer[128];
+        strerror_r(errno, errBuffer, sizeof(errBuffer));
+        fprintf(stderr, "Error reading stack limit: [%d] %s\n", errno, errBuffer);
+    }
+
+    uint64_t stackMin = (uint64_t)stackBase - (uint64_t)stackLimit.rlim_cur;
+    uint64_t stackMax = ((uint64_t)stackBase + 0x10000) & ~0xFFFFull; // Round to next higher multiple of 64 kB (should be safe on x86 systems)
+    PinNotifyStackPointer(stackMin, stackMax);
+}
+
+// Main trace target function. The following actions are performed:
+//     The current action is read from stdin.
+//     A line with "t" followed by a numeric ID, and another line with a file path determining a new testcase, that is subsequently loaded and fed into the target function, while calling PinNotifyNextFile() beforehand.
+//     A line with "e 0" terminates the program.
+void TraceFunc()
+{
+    // First transmit stack pointer information
+    ReadAndSendStackPointer();
+	
+	PinNotifyAllocation((uint64_t)&errno, 8);
+
+    // Run until exit is requested
+    char inputBuffer[512];
+    char errBuffer[128];
+	int targetInitialized = 0;
+    while(1)
+    {
+        // Read command and testcase ID (0 for exit command)
+        char command;
+        int testcaseId;
+        fgets(inputBuffer, sizeof(inputBuffer), stdin);
+        sscanf(inputBuffer, "%c %d", &command, &testcaseId);
+
+        // Exit or process given testcase
+        if(command == 'e')
+            break;
+        if(command == 't')
+        {
+            // Read testcase file name
+            fgets(inputBuffer, sizeof(inputBuffer), stdin);
+            int inputFileNameLength = strlen(inputBuffer);
+            if(inputFileNameLength > 0 && inputBuffer[inputFileNameLength - 1] == '\n')
+                inputBuffer[inputFileNameLength - 1] = '\0';
+
+            // Load testcase file and run target function
+            FILE* inputFile = fopen(inputBuffer, "rb");
+            if(!inputFile)
+            {
+                strerror_r(errno, errBuffer, sizeof(errBuffer));
+                fprintf(stderr, "Error opening input file '%s': [%d] %s\n", inputBuffer, errno, errBuffer);
+                continue;
+            }
+			
+			// If the target was not yet initialized, call the init function for the first test case
+			if(!targetInitialized)
+			{
+				InitTarget(inputFile);
+				fseek(inputFile, 0, SEEK_SET);
+				targetInitialized = 1;
+			}
+            
+            PinNotifyTestcaseStart(testcaseId);
+            RunTarget(inputFile);
+            PinNotifyTestcaseEnd();
+            
+            fclose(inputFile);
+        }
+    }
+}
+
+// Wrapper entry point.
+int main(int argc, const char** argv)
+{
+    // Run target function
+    TraceFunc();
+    return 0;
+}

microwalk/target-branch-leakage.c

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+#include <stdint.h>
+#include <stdio.h>
+
+#include <my_lib.h>
+
+extern void RunTarget(FILE* input)
+{
+    uint8_t plain[16];
+    if(fread(plain, 1, 16, input) != 16)
+        return;
+	
+	branch_leakage(plain, 16);
+}
+
+extern void InitTarget(FILE* input)
+{
+	init();
+	RunTarget(input);
+}