x/crypto/ssh: ParsePrivateKeyWithPassphrase returns an opaque error in case of wrong passphrase

[mattn]

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

go version devel +2f73efa971 Wed May 31 21:03:26 2017 +0000 windows/amd64

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

windows amd64

What did you do?

_, err = ssh.ParsePrivateKeyWithPassphrase(pembytes, []byte("incorrect"))
if err != nil {
  if isWrongPassword(err) {
    println("wrong password")
  } else {
    println("invalid key")
  }
}

It's difficult to implement isWrongPassword.

_, err = ssh.ParsePrivateKeyWithPassphrase(pembytes, []byte("incorrect"))
if err != nil {
  if err == ssh.ErrorXXX {
    println("wrong password")
  } else {
    println("invalid key")
  }
}

Hope to check with constant err value

[gopherbot]

CL https://golang.org/cl/46439 mentions this issue.