Problems verifying signature with autoimported keys

[Holger Sesterhenn]

Hi folks,

I am playing around with keyservers and the 'auto-key-retrieve' option and
have some problems to understand why a signature should be bad:

Environment:

userA at client
	enc keyid: 11111111111111111
	sig keyid: 11111111111111000
	local user

userB at internet
	enc keyid: 22222222222222222
	sig keyid: 22222222222222000
	send a signed and encrypted mail to userA
	public key is uploaded to keyserver
	encrypted to self

userC at company
	sig keyid: 33333333333333000
	has signed public key of userB
	this key is imported by userA,
	signed locally and trusted ultimate

GnuPG 1.2.1 on a SuSe 7.3 box, compiled with keyserver supported.
	
----------output decryption ---------------------
userA at client:~> gpg --keyserver "hkp://a.public.keyserver"\
--keyserver-options "auto-key-retrieve" --status-fd 2\
--decrypt signed-message

[GNUPG:] ENC_TO 11111111111111111 16 0
[GNUPG:] GOOD_PASSPHRASE
[GNUPG:] ENC_TO 22222222222222222 16 0
gpg: encrypted with 1024-bit ELG-E key, ID 11111111111, created 2000-06-06
        "userA <userA at client>"
[GNUPG:] NO_SECKEY 222222222222222222
gpg: encrypted with 1024-bit ELG-E key, ID 22222222222, created 2003-02-04
        "userB <userB at internet>"
[GNUPG:] BEGIN_DECRYPTION

<the message>

gpg: Signature made Tue Feb  4 19:08:18 2003 CET using DSA key ID 8C574710
[GNUPG:] SIG_ID skATzmEpRldO4qfomtEO27ZoSTg 2003-02-04 1044382098
[GNUPG:] GOODSIG 2222222222222000 userB <userB at internet>
gpg: Good signature from "userB <userB at internet>"
gpg:                 aka "alias userB <userB at somewhere>"
[GNUPG:] VALIDSIG 2222222222222222222000000 2003-02-04 1044382098 0
[GNUPG:] TRUST_FULLY
[GNUPG:] DECRYPTION_OKAY
gpg: WARNING: message was not integrity protected
[GNUPG:] END_DECRYPTION
-------------------------eot----------------------------------


-------------------------output list-sig ---------------------
userA at client:~> gpg --list-sig --with-colon --fixed-list-mode
/home/userA/.gnupg/pubring.gpg
-----------------------------------
pub:u:1024:17:1111111111111000:1044379131:::u:::scESC:
uid:u::::::::userA at client:
sig:::17:1111111111111000:1044379131::::userA at client:13x:
sub:u:1024:16:11111111111111111:1044379146::::::e:
sig:::17:11111111111111000:1044379146::::user at client:18x:

pub:f:1024:17:22222222222222000:960300007:::-:::scESC:
uid:f::::::::userB at internet:
sig:::17:3333333333333000:986092522::::userC at company:10x:
sig:::17:2222222222222000:973844196::::userB at internet:13x:
uid:f::::::::userB at somewhere:
sig:::17:33333333333333000:986092517::::userC at company:10x:
sig:::17:22222222222222000:960367629::::userB at internet:13x:
sub:f:1024:16:22222222222222222:960300030::::::e:
sig:::17:2222222222222000:960300030::::userB at internet:18x:

pub:u:1024:17:3333333333333000:951407044:::u:::scESC:
uid:u::::::::userC at company:
sig:::17:3333333333333000:1024068137::::userC at company:13x:
sig:::17:1111111111111000:1044383617::::userA at client:13l:
uid:u::::::::userC at old-company:
sig:::17:9999999999999000:955521701::::[User id not found]:10x:
sig:::17:3333333333333000:951407044::::userC at company:10x:
sig:::17:11111111111111000:1044383617::::userA at client:13l:
-------------------------eot----------------------------------

Signature 9999999999999000 is done by a "CA" (a german computer magazine)


Let me explain what I have done:

- created a new keypair for userA
- exported the public key of userA

- imported this key into the keyring of userB
- created a signed and encrypted message with sender userB and recipient
userA, using the encrypt-to <userB> in ./gnupg/options of userB

- userA at client: gpg --decrypt ... (see above)
    -> public key of userB was imported automatically
    -> bad signature message because no trusted signer

OK I understand why

- userA at client: gpg --recv-keys <keyid of userC>
- userA at client: gpg --edit <userC>
    - lsign ultimate
    - trust ultimate

- userA at client: gpg --decrypt ... (see above)
    -> bad signature message

WHY????

Exit code of gpg is always 0!


Some more explanations: I would like to import some hundred public keys
which are all signed by a "CA" key. Importing, signing and trusting this
"CA" key, the other keys should automatically be valid as recipient keys.

Adding some other "CA" keys and some public/private keyservers and you are
able to send encrypted mail to a big web of trust automatically (your
company with some branches, your resellers e.g.).

It would be great if someone could tell me what I'm doing wrong.


Best Regards,

Holger Sesterhenn