default to GOGARBLE=*, stop using GOPRIVATE

We can drop the code that kicked in when GOGARBLE was empty.
We can also add the value in addGarbleToHash unconditionally,
as we never allow it to be empty.

In the tests, remove all GOGARBLE lines where it just meant "obfuscate
everything" or "obfuscate the entire main module".

cgo.txtar had "obfuscate everything" as a separate step,
so remove it entirely.

linkname.txtar started failing because the imported package did not
import strings, so listPackage errored out. This wasn't a problem when
strings itself wasn't obfuscated, as transformLinkname silently left
strings.IndexByte untouched. It is a problem when IndexByte does get
obfuscated. Make that kind of listPackage error visible, and fix it.

reflect.txtar started failing with "unreachable method" runtime throws.
It's not clear to me why; it appears that GOGARBLE=* makes the linker
think that ExportedMethodName is suddenly unreachable.
Work around the problem by making the method explicitly reachable,
and leave a TODO as a reminder to investigate.

Finally, gogarble.txtar no longer needs to test for GOPRIVATE.
The rest of the test is left the same, as we still want the various
values for GOGARBLE to continue to work just like before.

Fixes burrowers#594.

CHANGELOG.md

@@ -7,6 +7,8 @@ and adds initial support for the upcoming Go 1.20.
 
 Noteworthy changes include:
 
+* `GOGARBLE=*` is now the default to obfuscate all packages - [#594]
+* `GOPRIVATE` is no longer used, being deprecated in [v0.5.0]
 * Obfuscate assembly source code filenames - [#605]
 * Randomize the lengths of obfuscated names
 * Support obfuscating `time` and `syscall`
@@ -157,6 +159,7 @@ Known bugs:
 * obfuscating the standard library with `GOPRIVATE=*` is not well supported yet
 * `garble test` is temporarily disabled, as it is currently broken
 
+[#594]: https://github.com/burrowers/garble/issues/594
 [#605]: https://github.com/burrowers/garble/issues/605
 
 [v0.7.2]: https://github.com/burrowers/garble/releases/tag/v0.7.2

README.md

@@ -34,12 +34,10 @@ order to:
 * [Obfuscate literals](#literal-obfuscation), if the `-literals` flag is given
 * Remove [extra information](#tiny-mode), if the `-tiny` flag is given
 
-The tool obfuscates the packages matching `GOGARBLE`, a comma-separated list of
-glob patterns of module path prefixes, as documented in `go help private`.
-To obfuscate all the packages in a build, use `GOGARBLE=*`.
-When `GOGARBLE` is empty, it assumes the value of `GOPRIVATE`.
-When `GOPRIVATE` is also empty, then `GOGARBLE` assumes the value of the current
-module path, to obfuscate all packages under the current module.
+By default, the tool obfuscates all the packages being built.
+You can manually specify which packages to obfuscate via `GOGARBLE`,
+a comma-separated list of glob patterns matching package path prefixes.
+This format is borrowed from `GOPRIVATE`; see `go help private`.
 
 Note that commands like `garble build` will use the `go` version found in your
 `$PATH`. To use different versions of Go, you can

bench_test.go

@@ -84,7 +84,6 @@ func BenchmarkBuild(b *testing.B) {
 		gocache, err := os.MkdirTemp(b.TempDir(), "gocache-*")
 		qt.Assert(b, err, qt.IsNil)
 		env := append(os.Environ(),
-			"GOGARBLE=*",
 			"GOCACHE="+gocache,
 			"GARBLE_WRITE_ALLOCS=true",
 		)

hash.go

@@ -98,9 +98,7 @@ func addGarbleToHash(inputHash []byte) []byte {
 	// We also need to add the selected options to the full version string,
 	// because all of them result in different output. We use spaces to
 	// separate the env vars and flags, to reduce the chances of collisions.
-	if cache.GOGARBLE != "" {
-		fmt.Fprintf(hasher, " GOGARBLE=%s", cache.GOGARBLE)
-	}
+	fmt.Fprintf(hasher, " GOGARBLE=%s", cache.GOGARBLE)
 	appendFlags(hasher, true)
 	// addGarbleToHash returns the sum buffer, so we need a new copy.
 	// Otherwise the next use of the global sumBuffer would conflict.

main.go

@@ -36,7 +36,6 @@ import (
 
 	"golang.org/x/exp/maps"
 	"golang.org/x/exp/slices"
-	"golang.org/x/mod/modfile"
 	"golang.org/x/mod/module"
 	"golang.org/x/mod/semver"
 	"golang.org/x/tools/go/ast/astutil"
@@ -998,7 +997,20 @@ func (tf *transformer) transformLinkname(localName, newName string) (string, str
 
 	lpkg, err := listPackage(pkgPath)
 	if err != nil {
-		// Probably a made up name like above, but with a dot.
+		// TODO(mvdan): use errors.As or errors.Is instead
+		if strings.Contains(err.Error(), "path not found") {
+			// Probably a made up name like above, but with a dot.
+			return localName, newName
+		}
+		if strings.Contains(err.Error(), "refusing to list") {
+			fmt.Fprintf(os.Stderr,
+				"//go:linkname refers to %s - add `import _ %q` so garble can find the package",
+				newName, pkgPath)
+			return localName, newName
+		}
+		if err != nil {
+			panic(err) // shouldn't happen
+		}
 		return localName, newName
 	}
 	if lpkg.ToObfuscate {
@@ -2185,7 +2197,8 @@ func flagSetValue(flags []string, name, value string) []string {
 
 func fetchGoEnv() error {
 	out, err := exec.Command("go", "env", "-json",
-		"GOOS", "GOPRIVATE", "GOMOD", "GOVERSION", "GOCACHE",
+		// Keep in sync with sharedCache.GoEnv.
+		"GOOS", "GOMOD", "GOVERSION",
 	).CombinedOutput()
 	if err != nil {
 		// TODO: cover this in the tests.
@@ -2201,23 +2214,8 @@ To install Go, see: https://go.dev/doc/install
 		return fmt.Errorf(`cannot unmarshal from "go env -json": %w`, err)
 	}
 	cache.GOGARBLE = os.Getenv("GOGARBLE")
-	if cache.GOGARBLE != "" {
-		// GOGARBLE is non-empty; nothing to do.
-	} else if cache.GoEnv.GOPRIVATE != "" {
-		// GOGARBLE is empty and GOPRIVATE is non-empty.
-		// Set GOGARBLE to GOPRIVATE's value.
-		cache.GOGARBLE = cache.GoEnv.GOPRIVATE
-	} else {
-		// If GOPRIVATE isn't set and we're in a module, use its module
-		// path as a GOPRIVATE default. Include a _test variant too.
-		// TODO(mvdan): we shouldn't need the _test variant here,
-		// as the import path should not include it; only the package name.
-		if mod, err := os.ReadFile(cache.GoEnv.GOMOD); err == nil {
-			modpath := modfile.ModulePath(mod)
-			if modpath != "" {
-				cache.GOGARBLE = modpath + "," + modpath + "_test"
-			}
-		}
+	if cache.GOGARBLE == "" {
+		cache.GOGARBLE = "*" // we default to obfuscating everything
 	}
 	return nil
 }

scripts/check-third-party.sh

@@ -38,8 +38,6 @@ modules=(
 
 SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 
-export GOGARBLE="*"
-
 exit_code=0
 
 show() {

shared.go

@@ -44,14 +44,12 @@ type sharedCache struct {
 	GOGARBLE string
 
 	// Filled directly from "go env".
-	// Remember to update the exec call when adding or removing names.
+	// Keep in sync with fetchGoEnv.
 	GoEnv struct {
 		GOOS string // i.e. the GOOS build target
 
-		GOPRIVATE string
 		GOMOD     string
 		GOVERSION string
-		GOCACHE   string
 	}
 }
 

testdata/script/asm.txtar

@@ -3,8 +3,6 @@
 # TODO: support arm64, at least
 [!amd64] skip 'the assembly is only written for amd64'
 
-env GOGARBLE=test/main
-
 garble build
 exec ./main
 cmp stderr main.stderr

testdata/script/cgo.txtar

@@ -1,7 +1,5 @@
 [!cgo] skip 'this test requires cgo to be enabled'
 
-env GOGARBLE=test/main
-
 garble build
 ! stderr 'warning' # check that the C toolchain is happy
 exec ./main
@@ -19,12 +17,6 @@ garble reverse .
 cmp stdout reversed.stdout
 env GARBLE_TEST_REVERSING=false
 
-env GOGARBLE=*
-garble build
-exec ./main
-cmp stdout main.stdout
-env GOGARBLE=test/main
-
 garble -tiny build
 exec ./main
 cmp stdout main.stdout

testdata/script/crossbuild.txtar

@@ -9,7 +9,6 @@
 [arm] env GOARCH=arm64
 
 # A fairly average Go build, importing some std libraries.
-env GOGARBLE='*'
 garble build
 -- go.mod --
 module test/main

testdata/script/debugdir.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=*
-
 garble -debugdir ./debug1 build
 exists 'debug1/test/main/imported/imported.go' 'debug1/test/main/main.go' 'debug1/reflect/type.go'
 exists 'debug1/runtime/map.go' 'debug1/runtime/funcdata.h' 'debug1/runtime/asm.s'

testdata/script/embed.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=*
-
 garble build
 
 exec ./main

testdata/script/gogarble.txtar

@@ -1,13 +1,8 @@
-# Ensure that "does not match any packages" works with GOPRIVATE and GOGARBLE.
+# Ensure that "does not match any packages" works.
 env GOGARBLE=match-absolutely/nothing
 ! garble build -o=out ./standalone
 stderr '^GOGARBLE="match-absolutely/nothing" does not match any packages to be built$'
 
-env GOGARBLE=
-env GOPRIVATE=match-absolutely/nothing
-! garble build -o=out ./standalone
-stderr '^GOGARBLE="match-absolutely/nothing" does not match any packages to be built$'
-
 # A build where just some packages are obfuscated.
 env GOGARBLE=test/main/imported
 garble -literals build -o=out ./importer
@@ -23,6 +18,7 @@ garble build -o=out ./stdimporter
 
 [short] stop # rebuilding std is slow
 
+# Go back to the default of obfuscating all packages.
 env GOGARBLE='*'
 
 # Try garbling all of std, given some std packages.

testdata/script/help.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=*
-
 ! garble
 stderr 'Garble obfuscates Go code'
 stderr 'garble \[garble flags\] command'

testdata/script/implement.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=test/main
-
 garble build
 exec ./main
 cmp stdout main.stdout

testdata/script/imports.txtar

@@ -1,7 +1,5 @@
-# Note that this is the only test with a module where we rely on the detection
-# of GOGARBLE.
-# Also note that, since this is the only test using "real" external modules
-# fetched via GOPROXY, go.mod and go.sum should declare the dependencies.
+# Since this is the only test using "real" external modules fetched via GOPROXY,
+# go.mod and go.sum should declare the dependencies.
 
 # For now, use a throwaway module download cache instead of the host machine's.
 # Usually it would be fine to reuse the host's, since we expose exact copies of

testdata/script/ldflags.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=*
-
 # Note the proper domain, since the dot adds an edge case.
 #
 # Also note that there are three forms of -X allowed:

testdata/script/linkname.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=test/main,big.chungus/meme
-
 garble build
 exec ./main
 cmp stderr main.stderr
@@ -76,6 +74,7 @@ func main() {
 package imported
 
 import (
+	_ "strings"
 	_ "unsafe"
 )
 

testdata/script/literals.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=*
-
 garble -literals build
 exec ./main$exe
 cmp stderr main.stderr
@@ -52,7 +50,6 @@ grep '^\s+\w+ = .*\bappend\(\w+,(\s+\w+\[\d+\][\^\-+]\w+\[\d+\],?)+\)$' debug1/t
 
 # Finally, sanity check that we can build all of std with -literals.
 # Analogous to gogarble.txt.
-env GOGARBLE='*'
 garble -literals build std
 -- go.mod --
 module test/main

testdata/script/modinfo.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=test/main
-
 [exec:git] exec git init -q
 [exec:git] exec git config user.name "name"
 [exec:git] exec git config user.email "[email protected]"

testdata/script/plugin.txtar

@@ -2,8 +2,6 @@ skip # TODO: get plugins working properly. See issue #87
 
 [windows] skip 'Go plugins are not supported on Windows'
 
-env GOGARBLE=test/main
-
 garble build -buildmode=plugin ./plugin
 binsubstr plugin.so 'PublicVar' 'PublicFunc'
 ! binsubstr plugin.so 'privateFunc'

testdata/script/position.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=test/main
-
 garble build
 exec ./main
 ! stdout 'garble_main\.go|garble_other_filename|is sorted'

testdata/script/reflect.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=test/main
-
 garble build
 exec ./main
 cmp stdout main.stdout
@@ -32,6 +30,8 @@ import (
 	"test/main/importedpkg2"
 )
 
+var Sink interface{}
+
 func main() {
 	// Fields still work fine when they are not obfuscated.
 	fmt.Println(importedpkg.ReflectInDefinedVar.ExportedField2)
@@ -41,9 +41,13 @@ func main() {
 	printfWithoutPackage("%T\n", importedpkg.ReflectTypeOf(2))
 	printfWithoutPackage("%T\n", importedpkg.ReflectTypeOfIndirect(4))
 
+
 	// More complex use of reflect.
 	v := importedpkg.ReflectValueOfVar
 	printfWithoutPackage("%#v\n", v)
+	// Keep the method from being unreachable, otherwise Call below may panic.
+	// TODO(mvdan): This only started being necessary with GOGARBLE=*. Why?
+	Sink = v.ExportedMethodName
 	method := reflect.ValueOf(&v).MethodByName("ExportedMethodName")
 	if method.IsValid() {
 		fmt.Println(method.Call(nil))

testdata/script/reverse.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=test/main
-
 # Unknown build flags should result in errors.
 ! garble reverse -badflag=foo .
 stderr 'flag provided but not defined'

testdata/script/seed-cache.txtar

@@ -7,7 +7,6 @@
 # In the past, this threw off garble's extra cached gob files.
 
 env SEED1=OQg9kACEECQ
-env GOGARBLE=*
 
 # First, ensure that mod1's garbletest.v2 is in the cache.
 cd mod1

testdata/script/seed.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=test/main
-
 # Note that in this test we use "! bincmp" on plaintext output files,
 # as a workaround for "cmp" not supporting "! cmp".
 # TODO: now that obfuscation with -seed is deterministic,

testdata/script/syntax.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE='test/main,private.source'
-
 garble build
 exec ./main$exe
 cmp stderr main.stderr

testdata/script/tiny.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=test/main
-
 # Tiny mode
 garble -tiny build
 ! binsubstr main$exe 'garble_main.go' 'fmt/print.go'

testdata/script/typeparams.txtar

@@ -1,5 +1,3 @@
-env GOGARBLE=*
-
 garble build
 ! binsubstr main$exe ${WORK} 'garble_main.go' 'GenericFunc' 'GenericVector' 'PredeclaredSignedInteger' 'StringableSignedInteger' 'CombineEmbeds' 'GenericParam'
 -- go.mod --