gpg: cannot open `/dev/tty': No such device or address

Message

charles17 · Post by **charles17** » Mon Jan 18, 2016 4:51 pm

Could someone help with this? I came across from the Pulling validated Gentoo ebuild tree snapshots of the handbook.

When I do

$ su -c "gpg --homedir /var/lib/gentoo/gkeys/keyrings/gentoo/release --edit-key 0xF6CD6C97 check"

it tells me

Password:
gpg: WARNING: unsafe permissions on homedir `/var/lib/gentoo/gkeys/keyrings/gentoo/release'
gpg (GnuPG) 2.0.28; Copyright (C) 2015 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

gpg: cannot open `/dev/tty': No such device or address

Searching the internet for this message I could not find a solution.
Any idea? What's the problem with gnupg and /dev/tty?

Princess Nell · Post by **Princess Nell** » Mon Jan 18, 2016 10:18 pm

The warning indicates the permissions of the "homedir" are wrong - they probably need to be 0700.

edit-key is by nature an interactive command, but you're not running interactively. Try --no-tty.

charles17 · Post by **charles17** » Tue Jan 19, 2016 11:59 am

Thanks Princess Nell for your answer.
Changed the permission to 700. But when I try with --no-tty

su -c "gpg --no-tty --homedir /var/lib/gentoo/gkeys/keyrings/gentoo/release --edit-key 0xF6CD6C97 check"

It would end up with

Password:
gpg (GnuPG) 2.0.28; Copyright (C) 2015 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

gpg: Sorry, no terminal at all requested - can't get input

That also doesn't look very promising.

But when I try it as root it works

root # gpg --homedir /var/lib/gentoo/gkeys/keyrings/gentoo/release/ --edit-key F6CD6C97 trust
gpg: WARNING: unsafe ownership on homedir `/var/lib/gentoo/gkeys/keyrings/gentoo/release/'
gpg (GnuPG) 2.0.28; Copyright (C) 2015 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

pub 4096R/F6CD6C97 created: 2014-10-03 expires: 2017-09-17 usage: C
trust: full validity: unknown
sub 4096R/151C3FC7 created: 2014-10-03 expires: 2017-09-17 usage: S
[ unknown] (1). Gentoo-keys Team <gkeys@gentoo.org>

pub 4096R/F6CD6C97 created: 2014-10-03 expires: 2017-09-17 usage: C
trust: full validity: unknown
sub 4096R/151C3FC7 created: 2014-10-03 expires: 2017-09-17 usage: S
[ unknown] (1). Gentoo-keys Team <gkeys@gentoo.org>

Please decide how far you trust this user to correctly verify other users' keys
(by looking at passports, checking fingerprints from different sources, etc.)

1 = I don't know or won't say
2 = I do NOT trust
3 = I trust marginally
4 = I trust fully
5 = I trust ultimately
m = back to the main menu

Your decision?

Why can't I do that from normal user with su -c?

Princess Nell · Post by **Princess Nell** » Tue Jan 19, 2016 10:16 pm

Use --batch, not --no-tty. And update those permissions

charles17 · Post by **charles17** » Wed Jan 20, 2016 8:25 am

Princess Nell wrote:Use --batch, not --no-tty. And update those permissions

Works for

$ su -c "gpg --batch --homedir /var/lib/gentoo/gkeys/keyrings/gentoo/release --edit-key 0xF6CD6C97 check"

But not for

$ su -c "gpg --batch --homedir /var/lib/gentoo/gkeys/keyrings/gentoo/release --edit-key 0xF6CD6C97 trust"
...
...
gpg: Sorry, we are in batchmode - can't get input

Seems that su -c "gpg ......." is not so recommended

Princess Nell · Post by **Princess Nell** » Wed Jan 20, 2016 9:39 pm

The second command is incomplete and waiting for input, so not a candidate for --batch in this form.