2016-11-07 21:08:44 +00:00
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# Fuzzer environment on ClusterFuzz
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2017-01-06 07:41:38 +00:00
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Your fuzz targets will be run on a [Google Compute Engine](https://cloud.google.com/compute/) VM (Linux) with some security restrictions.
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2016-11-07 21:08:44 +00:00
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2017-02-07 16:39:14 +00:00
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## Runtime Dependencies
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You should not make any assumptions on the availability of dependent packages
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in the execution environment. Packages that are installed via
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[Dockerfile](https://github.com/google/oss-fuzz/blob/master/docs/new_project_guide.md#dockerfile)
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2017-02-07 17:14:23 +00:00
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or built as part of
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[build.sh](https://github.com/google/oss-fuzz/blob/master/docs/new_project_guide.md#buildsh)
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are not available on the bot runtime environment (where the fuzz targets run).
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2017-02-07 17:14:23 +00:00
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If you need these dependencies in the runtime environment, you can either
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- Install the packages via Dockerfile
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([example](https://github.com/google/oss-fuzz/blob/master/projects/tor/Dockerfile#L19))
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and then link statically against them
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([example](https://github.com/google/oss-fuzz/blob/master/projects/tor/build.sh#L40))
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- Or build the dependencies statically in
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[build.sh](https://github.com/google/oss-fuzz/blob/master/docs/new_project_guide.md#buildsh)
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([example](https://github.com/google/oss-fuzz/blob/master/projects/ffmpeg/build.sh#L26)).
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2017-02-07 16:43:34 +00:00
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2017-02-08 03:15:53 +00:00
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All build artifacts needed during fuzz target execution should be inside the `$OUT`
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directory. Only those artifacts are archived and used on the bots. Everything else
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is ignored (e.g. artifacts in `$WORK`, `$SRC`, etc) and hence is not available
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in the execution environment.
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2017-01-14 20:20:48 +00:00
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2017-02-07 16:39:14 +00:00
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You should ensure that the fuzz target works correctly by using `run_fuzzer` command
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(see instructions [here](new_project_guide.md#testing-locally)). This command uses
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a clean base-runner docker container and not the base-builder docker container
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created during build-time.
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2017-01-10 20:44:14 +00:00
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2017-01-20 19:55:22 +00:00
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## argv[0]
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2018-04-02 05:28:18 +00:00
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You must not modify `argv[0]`. It is required for certain things to work correctly.
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2017-01-20 19:55:22 +00:00
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2016-11-07 21:08:44 +00:00
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## Current working directory
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2016-11-26 23:59:29 +00:00
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You should not make any assumptions about the current working directory of your
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2017-01-06 07:41:38 +00:00
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fuzz target. If you need to load data files, please use `argv[0]` to get the
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directory where your fuzz target executable is located.
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2016-11-07 21:08:44 +00:00
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2016-11-29 19:47:37 +00:00
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## File system
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2017-01-06 07:41:38 +00:00
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Everything except `/tmp` is read-only, including the directory that your fuzz target
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executable lives in.
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2016-12-09 16:49:42 +00:00
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`/dev` is also unavailable.
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2017-08-01 16:31:29 +00:00
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## Hardware
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Your project should not be compiled with `-march=native` or `-mtune=native`
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flags, as the build infrastructure and fuzzing machines may have different CPUs
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as well as other hardware differences. You may however use `-mtune=generic`.
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