The added test case used to crash garble:
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x8fe71b]
goroutine 1 [running]:
golang.org/x/tools/go/ast/astutil.Apply.func1(0xc0001e8880, 0xc000221570)
/go/pkg/mod/golang.org/x/tools@v0.0.0-20210115202250-e0d201561e39/go/ast/astutil/rewrite.go:47 +0x97
panic(0x975bc0, 0xd6c610)
/sdk/go1.15.8/src/runtime/panic.go:969 +0x1b9
go/types.(*Named).Obj(...)
/sdk/go1.15.8/src/go/types/type.go:473
mvdan.cc/garble.isTestSignature(0xc0001e7080, 0xa02e84)
/src/garble/main.go:1170 +0x7b
mvdan.cc/garble.(*transformer).transformGo.func2(0xc000122df0, 0xaac301)
/src/garble/main.go:1028 +0xff1
We were assuming that the first parameter was a named type, but that
might not be the case.
This crash was found out in the wild, from which a minimal repro was
written. We add two variants of it to the test data, just in case.
First, make isPrivate panic on malformed import paths, since that should
never happen. This catches the errors that some users had run into with
packages like gopkg.in/yaml.v2 and github.com/satori/go.uuid:
panic: malformed import path "gopkg.in/garbletest%2ev2": invalid char '%'
This seems to trigger when a module path contains a dot after the first
element, *and* that module is fetched via the proxy. This results in the
toolchain URL-encoding the second dot, and garble ends up seeing that
encoded path.
We reproduce this behavior with a fake gopkg.in module added to the test
module proxy. Using yaml.v2 directly would have been easier, but it's
pretty large. Note that we tried a replace directive, but that does not
trigger the URL-encoding bug.
Also note that we do not obfuscate the gopkg.in package; that's fine, as
the isPrivate path validity check catches the bug either way.
For now, make initImport use url.PathUnescape to work around this issue.
The underlying bug is likely in either the goobj2 fork, or in the
upstream Go toolchain itself.
hashImport also gives a better error if it cannot find a package now,
rather than just an "empty seed" panic.
Finally, the sanity check in isPrivate unearthed the fact that we do not
support garbling test packages at all, since they were invalid paths
which never matched GOPRIVATE. Add an explicit check and TODO about
that.
Fixes#224.
Fixes#228.
If code includes a linkname directive pointing at a name in an imported
package, like:
//go:linkname localName importedpackage.RemoteName
func localName()
We should rewrite the comment to replace "RemoteName" with its
obfuscated counterpart, if the package in question was obfuscated and
that name was as well.
We already had some code to handle linkname directives, but only to
ensure that "localName" was never obfuscated. This behavior is kept, to
ensure that the directive applies to the right name. In the future, we
could instead rewrite "localName" in the directive, like we do with
"RemoteName".
Add plenty of tests, too. The linkname directive used to be tested in
imports.txt and syntax.txt, but that was hard to maintain as each file
tested different edge cases.
Now that we have build caching, adding one extra testscript file isn't a
big problem anymoree. Add linkname.txt, which is self-explanatory. The
other two scripts also get a bit less complex.
Fixes#197.
It turns out that the modules we include in testdata/mod via
txtar-addmod don't result in the same h1 hash that one gets when using
proxy.golang.org.
As proof:
$ go clean -modcache && go get -d rsc.io/quote@v1.5.2 && go test -short
[...]
--- FAIL: TestScripts/imports (0.06s)
> garble build -tags buildtag
go list error: exit status 1: verifying rsc.io/quote@v1.5.2: checksum mismatch
downloaded: h1:w5fcysjrx7yqtD/aO+QwRjYZOKnaM9Uh2b40tElTs3Y=
go.sum: h1:3fEykkD9k7lYzXqCYrwGAf7iNhbk4yCjHmKBN9td4L0=
The added comment explains the situation in detail.
For now, simply work around the issue by not sharing GOMODCACHE with the
host.
In Go 1.15, if a dependency is required but not listed in go.mod/go.sum,
it's resolved and added automatically.
This is changing in 1.16. From that release, one will have to explicitly
update the mod files via 'go mod tidy' or 'go get'.
To get ahead of the curve, start using -mod=readonly to get the same
behavior in 1.15, and fix all existing tests.
The only tests that failed were imports.txt and syntax.txt, the only
ones to require other modules. But since we're here, let's add the 'go'
line to all go.mod files as well.
The test intended to use an extra module to be obfuscated, rsc.io/quote,
which we were bundling in the local proxy as well. Unfortunately, the
use of GOPRIVATE also meant that we did not actually fetch the module
from the proxy, and we would instead do a full roundtrip to the internet
to "git clone" the actual upstream repository.
To prevent that roundtrip, instead use a locally replaced module. This
fits the syntax.txt test too, since it's one more edge case that we want
to make sure works well with garble. Since rsc.io/quote is used in
another test, simply make up our own tiny module.
Reduces a 'go test -run Syntax/syntax' run with warm cache from ~5s to
~0.5s, thanks to removing the multiple roundtrips. A warm 'go test' run
still sits at ~6s, since we still need that much CPU time in total.
While at it, fix a staticcheck warning and fix inconsistent indentation
in a couple of tests.
More correct comments transformation was implemented.
Added processing of //go:linkname localname [importpath.name] directive, now localname is not renamed. This is safe and does not cause a name disclosure because the functions marked //linkname do not have a name in the resulting binary.
Added cgo directives support
Fixed filename leak protection for cgo
Part of #149
Fix for bug when a conflict occurred between generated short names
and local variables/functions/types/structs.
The already existing names are collected and if the generated short name
already exists, the package counter is increased until a free name is found.
Part of #149.
In tiny.txt, we already check line numbers via stderr, so there's no
need to do that via -debugdir.
In syntax.txt, we only really care about what names remain in the
binary, not the names which remain in the source but don't affect the
binary.
These changes are important because -debugdir adds a non-trivial amount
of work, which will impede build caching once that feature lands. We
will likely make -debugdir support build caching eventually, but for
now, this preliminary change will make 'go test' much faster with build
caching.
And of course, the tests get simpler, which is nice.
Finally, finally this is done. This allows import paths to be obfuscated by modifying
object/archive files and garbling import paths contained within. The bulk of the
code that makes parsing and writing Go object/archive files possible lives at
https://github.com/Binject/debug/tree/master/goobj2, which I wrote as well.
I have tested by garbling and checking for import paths via strings and grep
(in order of difficulty) https://github.com/lu4p/binclude, garble itself, and
https://github.com/dominikh/go-tools/tree/master/cmd/staticcheck.
This only supports object/archive files produced from the Go 1.15 compiler.
The object file format changed at 1.15, and 1.14 and earlier is not supported.
Fixes#13.
basic.txt just builds main.go without a module. Similarly, we leave
imports.txt without a GOPRIVATE, to test the 'go list -m' fallback.
For all other tests, explicitly set GOPRIVATE, to avoid two exec calls -
both 'go env GOPRIVATE' as well as 'go list -m'. Each of those calls
takes in the order of 10ms, so saving ~26 exec calls should easily add
to 200-300ms saved from 'go test -short'.
Error strings should never be capitalized.
A binsubstr line in one of the tests was duplicate and thus useless.
Remove duplicate or trailing spaces in test scripts.
Finally, add a TODO for an optimization I just spotted.
Fixes #2.
Line numbers are now obfuscated, via `//line` comments.
Filenames are now obfuscated via `//line` comments, instead of changing the actual filename.
New flag `-tiny` to reduce the binary size, at the cost of reversibility.
The following identifiers are now skipped,
because they never show up in the binary:
- constant identifiers
- identifiers of local variables
(includes function params and named returns)
- identifiers of local types
Whilst it may not be particularly common, it is legal to embed fields
where the type has universe scope (e.g. int, error, etc). This can
cause a panic in 2 difference places:
- When embedding `error`, a named type is resolved but the package is
nil. The call to `pkg.Name()` results in a panic
- When embedding a basic type such as `int`, no named type is resolved
at all. The call to `namedType(obj.Type()).Obj()` results in a panic
I'm assuming it is OK to return early when a named type cannot be
resolved.. we could let it continue but I think `pkg` should be set to
nil to be correct, so it'd end up returning straight away anyway.
In the added test case, we'd see a failure, since we garbled the name of
the "Embedded" type but not its use as an anonymous field. Garble both.
This might possibly break some reflect code, but it doesn't seem like we
have an option. When we garble a type, it's impossible to tell if it's
going to be used as an anonymous field later.
Updates #9.
Daniel Martí
Andrew LeFevre
pagran
pagran
lu4p
Nicholas Jones