x/crypto/ssh PublicKeys example is failing with key type ssh-rsa not in PubkeyAcceptedAlgorithms error on sshd

[fengye87]

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

$ go version
go version go1.16.6 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/fengye87/.cache/go-build"
GOENV="/home/fengye87/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/fengye87/go/1.16.6/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/fengye87/go/1.16.6"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/fengye87/.goenv/versions/1.16.6"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/fengye87/.goenv/versions/1.16.6/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.16.6"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/fengye87/workspace/demo/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 -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build2394764193=/tmp/go-build -gno-record-gcc-switches"

What did you do?

The x/crypto/ssh PublicKeys example is failing. The client side error is ssh: handshake failed: ssh: unable to authenticate, attempted methods [none publickey], no supported methods remain. But the key works perfectly with ssh -i command. There's a sshd error message says userauth_pubkey: key type ssh-rsa not in PubkeyAcceptedAlgorithms [preauth].

The key I'm using is generated using plain ssh-keygen. Since ssh -i can work, my guess is that pub.Type() may not be a valid value in this case?

What did you expect to see?

The example should work as expected

What did you see instead?

The example is not working

[toothrot]

What version of openssh do you have installed?

#46569 #37278

[fengye87]

@toothrot

local:

$ rpm -qa | grep openssh
openssh-server-7.4p1-21.el7.x86_64
openssh-clients-7.4p1-21.el7.x86_64
openssh-7.4p1-21.el7.x86_64

remote:

$ rpm -qa | grep openssh
openssh-8.6p1-3.fc34.x86_64
openssh-clients-8.6p1-3.fc34.x86_64
openssh-server-8.6p1-3.fc34.x86_64

After looking at #37278, I believe this is a dup. I'm closing this. Thanks for the help.