c9deff810b
Previously, we were never obfuscating runtime and its direct dependencies. Unfortunately, due to linkname, the runtime package is actually closely related to dozens of other std packages as well. Until we can obfuscate the runtime and properly support go:linkname directives, obfuscating fewer std packages is a better outcome than breaking and not producing any obfuscated code at all. The added test case is building runtime/pprof, which used to cause failures: # runtime/pprof /go/src/runtime/pprof/label.go:27:21: undefined: context.Context /go/src/runtime/pprof/label.go:59:21: undefined: context.Context /go/src/runtime/pprof/label.go:93:16: undefined: context.Context /go/src/runtime/pprof/label.go:101:20: undefined: context.Context The net package was also very close to obfuscating properly thanks to this change, so its test is now run as well. The only other remaining fix was to not obfuscate fields on cgo types, since those aren't obfuscated at the moment. The map is pretty long, but it's only a temporary solution and the command to obtain the list again is included. Never obfuscating the entire std library is also an option, but it's a bit unnecessary. Fixes #134. |
4 years ago | |
|---|---|---|
| .github | 5 years ago | |
| internal | 5 years ago | |
| scripts | 4 years ago | |
| testdata | 4 years ago | |
| .gitattributes | 5 years ago | |
| .gitignore | 5 years ago | |
| AUTHORS | 5 years ago | |
| CONTRIBUTING.md | 5 years ago | |
| LICENSE | 5 years ago | |
| README.md | 5 years ago | |
| bench_test.go | 5 years ago | |
| go.mod | 5 years ago | |
| go.sum | 5 years ago | |
| hash.go | 5 years ago | |
| import_obfuscation.go | 5 years ago | |
| line_obfuscator.go | 5 years ago | |
| main.go | 4 years ago | |
| main_test.go | 5 years ago | |
| runtime_strip.go | 5 years ago | |
| shared.go | 4 years ago | |
README.md
garble
GO111MODULE=on go get mvdan.cc/garble
Obfuscate Go code by wrapping the Go toolchain. Requires Go 1.15 or later, since Go 1.14 uses an entirely different object format.
garble build [build flags] [packages]
See garble -h for up to date usage information.
Purpose
Produce a binary that works as well as a regular build, but that has as little information about the original source code as possible.
The tool is designed to be:
- Coupled with
cmd/go, to support modules and build caching - Deterministic and reproducible, given the same initial source code
- Reversible given the original source, to un-garble panic stack traces
Mechanism
The tool wraps calls to the Go compiler and linker to transform the Go build, in order to:
- Replace as many useful identifiers as possible with short base64 hashes
- Replace package paths with short base64 hashes
- Remove all build and module information
- Strip filenames and shuffle position information
- Strip debugging information and symbol tables
- Obfuscate literals, if the
-literalsflag is given - Removes extra information if the
-tinyflag is given
Options
By default, the tool garbles the packages under the current module. If not
running in module mode, then only the main package is garbled. To specify what
packages to garble, set GOPRIVATE, documented at go help module-private.
Caveats
Most of these can improve with time and effort. The purpose of this section is to document the current shortcomings of this tool.
-
Exported methods are never garbled at the moment, since they could be required by interfaces and reflection. This area is a work in progress.
-
Functions implemented outside Go, such as assembly, aren't garbled since we currently only transform the input Go source.
-
Go plugins are not currently supported; see #87.
Tiny Mode
When the -tiny flag is passed, extra information is stripped from the resulting
Go binary. This includes line numbers, filenames, and code in the runtime the
prints panics, fatal errors, and trace/debug info. All in all this can make binaries
6-10% smaller in our testing.
Note: if -tiny is passed, no panics, fatal errors will ever be printed, but they can
still be handled internally with recover as normal. In addition, the GODEBUG
environmental variable will be ignored.
Contributing
We actively seek new contributors, if you would like to contribute to garble use the CONTRIBUTING.md as a starting point.