crypto/tls: TestVersion incorrectly tests "tls10default"

[stevenjohnstone]

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

$ go version
go version devel go1.19-5fd0ed7aaf Wed Mar 16 07:03:20 2022 +0000 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/stevie/.cache/go-build"
GOENV="/home/stevie/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/stevie/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/stevie/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/stevie/golang"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/stevie/golang/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel go1.19-5fd0ed7aaf Wed Mar 16 07:03:20 2022 +0000"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/stevie/golang/src/go.mod"
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-build478804125=/tmp/go-build -gno-record-gcc-switches"

What did you do?

go/src/crypto/tls/handshake_server_test.go

Line 410 in 5fd0ed7

if state.Version != VersionTLS11 {

"state.Version" is checked but "state" captures the state of the TLS connection immediately after the first handshake in the test, not the last. This means the final check of the TLS version used will always pass even if we break "tls10default" environment variable support.

What did you expect to see?

Something like this:

diff --git a/src/crypto/tls/handshake_server_test.go b/src/crypto/tls/handshake_server_test.go
index 6d2c405626..df7094cef9 100644
--- a/src/crypto/tls/handshake_server_test.go
+++ b/src/crypto/tls/handshake_server_test.go
@@ -403,7 +403,7 @@ func TestVersion(t *testing.T) {

        defer func(old bool) { debugEnableTLS10 = old }(debugEnableTLS10)
        debugEnableTLS10 = true
-       _, _, err = testHandshake(t, clientConfig, serverConfig)
+       state, _, err = testHandshake(t, clientConfig, serverConfig)
        if err != nil {
                t.Fatalf("handshake failed: %s", err)
        }

What did you see instead?

Stale version of a variable is used.

[gopherbot]

Change https://go.dev/cl/393334 mentions this issue: crypto/tls: fix TestVersion

[heschi]

cc @FiloSottile @agl @rolandshoemaker

[stevenjohnstone]

f0ee7fd removes the code in question.