debug/dwarf: infinite loop in dwarf.New

[catenacyber]

What version of Go are you using (go version)?

$ go version
go version go1.17.6 darwin/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/catena/Library/Caches/go-build"
GOENV="/Users/catena/Library/Application Support/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/catena/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/catena/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="go1.17.6"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/catena/go/src/github.com/catenacyber/go/src/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/pp/dc1dtf9x2js3v0jx_m010nqr0000gn/T/go-build4237848497=/tmp/go-build -gno-record-gcc-switches -fno-common"
GOROOT/bin/go version: go version go1.17.6 darwin/amd64
GOROOT/bin/go tool compile -V: compile version go1.17.6
uname -v: Darwin Kernel Version 21.3.0: Wed Jan  5 21:37:58 PST 2022; root:xnu-8019.80.24~20/RELEASE_X86_64
ProductName:	macOS
ProductVersion:	12.2.1
BuildVersion:	21D62
lldb --version: lldb-1316.0.9.41
Apple Swift version 5.6 (swiftlang-5.6.0.323.62 clang-1316.0.20.8)
gdb --version: GNU gdb (GDB) 9.1

What did you do?

Run https://go.dev/play/p/zQRoO7qmvKO

What did you expect to see?

The program finishing and printing somme dummy data

What did you see instead?

timeout running program

Possible fix is

diff --git a/src/debug/dwarf/unit.go b/src/debug/dwarf/unit.go
index 9b3d6e902d..ebd7fe837a 100644
--- a/src/debug/dwarf/unit.go
+++ b/src/debug/dwarf/unit.go
@@ -63,7 +63,7 @@ func (d *Data) parseUnits() ([]unit, error) {
                u := &units[i]
                u.base = b.off
                var n Offset
-               for n == 0 {
+               for n == 0 && b.err == nil {
                        n, u.is64 = b.unitLength()
                }
                dataOff := b.off

cc @neild as we have already been talking about this

Found by https://github.com/catenacyber/ngolo-fuzzing

[heschi]

cc @aclements @thanm

[thanm]

Interesting, I'll take a look.

[ianlancetaylor]

Seems like a variant of #47653.

[gopherbot]

Change https://go.dev/cl/393874 mentions this issue: debug/dwarf: better error detection in parseUnits