2.9 KiB
base-builder
Abstract base image for libfuzzer builders.
Every project image supports multiple commands that can be invoked through docker after the image is built:
docker run --rm -ti ossfuzz/$project <command> <arguments...>
Supported Commands
| Command | Description |
|---|---|
compile (default) |
build all fuzz targets |
/bin/bash |
drop into shell, execute compile script to start build. |
Build Configuration
A single build image can build same set of fuzzers in many configurations. The configuration is picked through one or more environment variables.
| Env Variable | Description |
|---|---|
$SANITIZER ("address") |
Specifies predefined sanitizer configuration to use. address or memory or undefined. |
$SANITIZER_FLAGS |
Specify compiler sanitizer flags directly. Overrides $SANITIZER. |
$COVERAGE_FLAGS |
Specify compiler flags to use for fuzzer feedback coverage. |
$BUILD_UID |
User id to use while building fuzzers. |
Examples
-
building sqlite3 fuzzer with UBSan (
SANITIZER=undefined):
docker run --rm -ti -e SANITIZER=undefined ossfuzz/sqlite3
Image Files Layout
| Location | Env | Description |
|---|---|---|
/out/ |
$OUT |
Directory to store build artifacts (fuzz targets, dictionaries, options files, seed corpus archives). |
/src/ |
$SRC |
Directory to checkout source files |
/work/ |
$WORK |
Directory for storing intermediate files |
/usr/lib/libFuzzingEngine.a |
$LIB_FUZZING_ENGINE |
Location of prebuilt fuzzing engine library (e.g. libFuzzer ) that needs to be linked with all fuzz targets (-lFuzzingEngine). |
While files layout is fixed within a container, the environment variables are provided to be able to write retargetable scripts.
Compiler Flags
You must use special compiler flags to build your project and fuzz targets. These flags are provided in following environment variables:
| Env Variable | Description |
|---|---|
$CC |
The C compiler binary. |
$CXX, $CCC |
The C++ compiler binary. |
$CFLAGS |
C compiler flags. |
$CXXFLAGS |
C++ compiler flags. |
Most well-crafted build scripts will automatically use these variables. If not, pass them manually to the build tool.
Child Image Interface
Sources
Child image has to checkout all sources that it needs to compile fuzz targets into
$SRC directory. When the image is executed, a directory could be mounted on top
of these with local checkouts using
docker run -v $HOME/my_project:/src/my_project ....
Other Required Files
Following files have to be added by child images:
| File Location | Description |
|---|---|
$SRC/build.sh |
build script to build the project and its fuzz targets |