debug/pe: check for PE or PE32+ executable is not fully correct

[alfonsosanchezbeato]

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

$ go version
go version go1.18.1 linux/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="/home/abeato/.cache/go-build"
GOENV="/home/abeato/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/abeato/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/abeato/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/go-1.18"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go-1.18/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.18.1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/dev/null"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3245950783=/tmp/go-build -gno-record-gcc-switches"

What did you do?

Looking at the code in https://github.com/golang/go/blob/master/src/debug/pe/file.go#L325 , the debug/pe package detects if the file is a PE or PE+ executable by looking at the machine type. However, this is not fully correct. According to the spec (https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#optional-header-image-only), the type of executable should be determined by looking at the first two bytes of the optional header, which should contain 0x10b for PE or 0x20b for PE+. Probably if the machine is 64 bits that implies PE+, but maybe that's not true in 100% of the cases.

What did you expect to see?

NA

What did you see instead?

NA

[dmitshur]

CC @alexbrainman.

[gopherbot]

Change https://go.dev/cl/421394 mentions this issue: debug/pe: use correct pe64 test in ImportedSymbols