On Mon, Aug 15, 2016 at 08:19:33AM +0200, Jan Cholasta wrote: > On 9.8.2016 16:47, Fraser Tweedale wrote: > > On Mon, Aug 08, 2016 at 10:49:27AM +0200, Jan Cholasta wrote: > > > On 8.8.2016 09:06, Fraser Tweedale wrote: > > > > On Mon, Aug 08, 2016 at 08:54:05AM +0200, Jan Cholasta wrote: > > > > > Hi, > > > > > > > > > > On 8.8.2016 06:34, Fraser Tweedale wrote: > > > > > > Please review the attached patch with adds --certificate-out and > > > > > > --certificate-chain-out options to `ca-show' command. > > > > > > > > > > > > Note that --certificate-chain-out currently writes a bogus file due > > > > > > to a bug in Dogtag that will be fixed in this week's build. > > > > > > > > > > > > https://fedorahosted.org/freeipa/ticket/6178 > > > > > > > > > > 1) The client-side *-out options should be defined on the client > > > > > side, not > > > > > on the server side. > > > > > > > > > Will option defined on client side be propagated to, and observable > > > > in the ipaserver plugin? The ipaserver plugin needs to observe that > > > > *-out has been requested and executes additional command(s) on that > > > > basis. > > > > > > Is there a reason not to *always* return the certs? > > > > > We hit Dogtag to retrieve them. > > I don't think that's an issue in a -show command. > cert_show is invoked by other commands (cert_find*, cert_show, cert_request, cert_status, ca_del) but these all hit Dogtag anyway so I suppose that's fine. I'll return the cert *and* the chain in separate attributes, unconditionally.
> > > > > > > > > > > > > > > > 2) I don't think there should be additional information included in > > > > > summary > > > > > (and it definitely should not be multi-line). I would rather inform > > > > > the user > > > > > via an error message when unable to write the files. > > > > > > > > > I was just following the pattern of other commands that write certs, > > > > profile config, etc. Apart from consistency with other commands I > > > > agree that there is no need to have it. So I will remove it. > > > > > > > > > If you think there is an actual value in informing the user about > > > > > successfully writing the files, please use ipalib.messages for the > > > > > job. > > > > > > > > > > > > > > > 3) IMO a better format for the certificate chain than PKCS#7 would be > > > > > concatenated PEM, as that's the most commonly used format in IPA (in > > > > > installers, there are no cert chains in API commands ATM). > > > > > > > > > Sure, but the main use case isn't IPA. Other apps require PKCS #7 > > > > or concatenated PEMs, but sometimes they must be concatenated > > > > forward, and othertimes backwards. There is no one size fits all. > > > > > > True, which is exactly why I think we should at least be self-consistent > > > and > > > use concatenated PEM (and multi-value DER over the wire). > > > > > Dogtag returns a PKCS7 (either DER or PEM, according to HTTP Accept > > header). > > > > If we want list-of-PEMs between server and client we have to convert > > on the server. Do we have a good way of doing this without exec'ing > > `openssl pkcs7' on the server? Is it acceptable to exec 'openssl' > > to do the conversion on the server? python-nss does not have PKCS7 > > functions and I am not keen on adding a pyasn1 PKCS7 parser just for > > the sake of pushing bits as list-of-PEMs. > > I'm afraid we can't avoid conversion to/from PKCS#7 one way or the other. > For example, if we added a call to retrieve external CA chain using certs > from cn=certificates,cn=ipa,cn=etc, we would have to convert the result to > PKCS#7 if it was our cert chain format of choice. > > What we can avoid though is executing "openssl pkcs7" to do the conversion - > we can use an approach similar to our DNSSEC code and use python-cffi to > call libcrypto's PKCS#7 conversion routines instead. > I had a look at the OpenSSL API for parsing PKCS #7; now I prefer to exec `openssl' to do the job :) I will transmit DER-encoded PKCS #7 object on the wire; we cannot used multi-valued DER attribute because order is important. Client will convert to PEMs. Should have new patch on list this afternoon. Thanks, Fraser > > > > FWIW, man pages and code suggest that PKCS #7 is accepted in > > installer, etc. > > True, but that's a relatively new feature (since 4.1) and the installer > internally executes "openssl pkcs7" to convert PKCS #7 to list of certs :-) > > > > > > > We can add an option to control the format later, but for now, > > > > Dogtag returns a PKCS #7 (PEM or DER) so let's go with that. Worst > > > > case is an admin has to invoke `openssl pkcs7' and concat the certs > > > > themselves. > > > > > > AFAIK none of NSS, OpenSSL or p11-kit can use PKCS#7 cert chains directly, > > > so I'm afraid the worst case would happen virtually always. > > > > > If you're OK with invoking OpenSSL on the client to convert PKCS #7 > > to list-of-PEMs (similar to what is done in > > ipapython.certdb.NSSDatabase) then we can have the client perform > > the conversion. > > See above. > > > > > > > > > > > > > > > > > 4) Over the wire, the certs should be DER-formatted, as that's the > > > > > most > > > > > common wire format in other API commands. > > > > > > > > > OK. > > > > > > > > > > > > > > 5) What is the benefit in having the CA cert and the rest of the chain > > > > > separate? For end-entity certs it makes sense to separate the cert > > > > > from the > > > > > CA chain, but for CA certs, you usually want the full chain, no? > > > > > > > > > If you want to anchor trust directly at a subca (e.g. restrict VPN > > > > login to certs issued by VPN sub-CA) then you often just want the > > > > cert. The chain option does subsume it, at cost of more work for > > > > administrators with this use case. I think it makes sense to keep > > > > both options. > > > > > > Does it? From what you described above, you either want just the sub-CA > > > cert, or the full chain including the sub-CA cert, in which case it might > > > make more sense to have a single --out option and a --chain flag. > > > > > How about --certificate-out which defaults to single cert, but does > > chain (as list-of-PEMs) when --chain flag given. > > > > Per https://fedorahosted.org/freeipa/ticket/5166 let's not add more > > `--out' options. > > +1 > > > > > Thanks, > > Fraser > > > > > -- > Jan Cholasta -- Manage your subscription for the Freeipa-devel mailing list: https://www.redhat.com/mailman/listinfo/freeipa-devel Contribute to FreeIPA: http://www.freeipa.org/page/Contribute/Code
