Read-only on /dev/tty causes ssh-add to show passwords when typed and ssh'ing to new hosts to fail

[Damien Miller]

On Fri, 18 Jul 2014, James Keener wrote:

> When permissions on /dev/tty are crw------- and owner root:root, ssh-add
> will echo passwords to the terminal (sudo does not) and ssh fails with a
> "Host key verification failed." error.

I would expect that ssh can't successfully issue termios calls to turn off
tty echo when /dev/tty isn't writable to the user. sudo will work because
it is setuid root.

There isn't much ssh can do with bad permissions on /dev/tty.

-d