Re: [libvirt PATCH 0/2] docs: less docs for insecure SASL mechanisms
On Mon, Mar 08, 2021 at 12:00:03PM +0100, Erik Skultety wrote: > On Mon, Mar 08, 2021 at 10:41:55AM +, Daniel P. Berrangé wrote: > > On Fri, Mar 05, 2021 at 08:02:49AM +0100, Erik Skultety wrote: > > > On Thu, Mar 04, 2021 at 06:10:11PM +, Daniel P. Berrangé wrote: > > > > GSSAPI and SCRAM-SHA-256 are the only two SASL mechanisms we > > > > especially want people to be using. Even the latter is a little > > > > questionable due to storing passwords in cleartext on the server. > > > > > > At what point of the SCRAM-SHA-256 auth process is password handled as > > > clear > > > text? I mean I tried to look up the issue you mention and couldn't find > > > anything, quite the contrary, e.g. Postgres says SCRAM-SHA-256 is the only > > > recommended scheme for password-based auth and storing passwords in clear > > > text > > > is not possible. Isn't it kind of the point that passwords are never > > > stored in > > > clear text with this scheme? > > > > You can clearly see the passwd in clear text in the file > > > > Add a new user > > > > $ echo "fish food" | saslpasswd2 -a libvirt demo > > > > Look for the password: > > > > $ strings /etc/libvirt/passwd.db | grep fish > > fish food > > > > The actual mechanism protocol does send in clear text over the wire. > > The storage in clear text on the server side is simply a choice of the > > cyrus-sasl impl of this mechanism documented here: > > > > https://www.cyrusimap.org/sasl/sasl/faqs/plaintextpasswords.html > > So if this is the case, why are we even bothering promoting an insecure > solution, why not promote only GSSAPI for the reasons given? Backcompat? Calling it insecure is a rather absolutist view of security IMHO. It *is* secure against network attackers, which is the primary risk factor we're protecting against with our use of SASL. To compromise the passwords requires the attacker to first compromise the root account on the virt host. Anything is possible, but IMHO that danger doesn't justify eliminating the SCRAM auth mechanism. If we only promote GSSAPI, then the result is likely to be that people run with no authentication at all, or make their own ill informed worse choices. Regards, Daniel -- |: https://berrange.com -o-https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o-https://fstop138.berrange.com :| |: https://entangle-photo.org-o-https://www.instagram.com/dberrange :|
Re: [libvirt PATCH 0/2] docs: less docs for insecure SASL mechanisms
On Mon, Mar 08, 2021 at 10:41:55AM +, Daniel P. Berrangé wrote: > On Fri, Mar 05, 2021 at 08:02:49AM +0100, Erik Skultety wrote: > > On Thu, Mar 04, 2021 at 06:10:11PM +, Daniel P. Berrangé wrote: > > > GSSAPI and SCRAM-SHA-256 are the only two SASL mechanisms we > > > especially want people to be using. Even the latter is a little > > > questionable due to storing passwords in cleartext on the server. > > > > At what point of the SCRAM-SHA-256 auth process is password handled as clear > > text? I mean I tried to look up the issue you mention and couldn't find > > anything, quite the contrary, e.g. Postgres says SCRAM-SHA-256 is the only > > recommended scheme for password-based auth and storing passwords in clear > > text > > is not possible. Isn't it kind of the point that passwords are never stored > > in > > clear text with this scheme? > > You can clearly see the passwd in clear text in the file > > Add a new user > > $ echo "fish food" | saslpasswd2 -a libvirt demo > > Look for the password: > > $ strings /etc/libvirt/passwd.db | grep fish > fish food > > The actual mechanism protocol does send in clear text over the wire. > The storage in clear text on the server side is simply a choice of the > cyrus-sasl impl of this mechanism documented here: > > https://www.cyrusimap.org/sasl/sasl/faqs/plaintextpasswords.html So if this is the case, why are we even bothering promoting an insecure solution, why not promote only GSSAPI for the reasons given? Backcompat? Erik
Re: [libvirt PATCH 0/2] docs: less docs for insecure SASL mechanisms
On Fri, Mar 05, 2021 at 08:02:49AM +0100, Erik Skultety wrote: > On Thu, Mar 04, 2021 at 06:10:11PM +, Daniel P. Berrangé wrote: > > GSSAPI and SCRAM-SHA-256 are the only two SASL mechanisms we > > especially want people to be using. Even the latter is a little > > questionable due to storing passwords in cleartext on the server. > > At what point of the SCRAM-SHA-256 auth process is password handled as clear > text? I mean I tried to look up the issue you mention and couldn't find > anything, quite the contrary, e.g. Postgres says SCRAM-SHA-256 is the only > recommended scheme for password-based auth and storing passwords in clear text > is not possible. Isn't it kind of the point that passwords are never stored in > clear text with this scheme? You can clearly see the passwd in clear text in the file Add a new user $ echo "fish food" | saslpasswd2 -a libvirt demo Look for the password: $ strings /etc/libvirt/passwd.db | grep fish fish food The actual mechanism protocol does send in clear text over the wire. The storage in clear text on the server side is simply a choice of the cyrus-sasl impl of this mechanism documented here: https://www.cyrusimap.org/sasl/sasl/faqs/plaintextpasswords.html Regards, Daniel -- |: https://berrange.com -o-https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o-https://fstop138.berrange.com :| |: https://entangle-photo.org-o-https://www.instagram.com/dberrange :|
Re: [libvirt PATCH 0/2] docs: less docs for insecure SASL mechanisms
On Thu, Mar 04, 2021 at 06:10:11PM +, Daniel P. Berrangé wrote: > GSSAPI and SCRAM-SHA-256 are the only two SASL mechanisms we > especially want people to be using. Even the latter is a little > questionable due to storing passwords in cleartext on the server. At what point of the SCRAM-SHA-256 auth process is password handled as clear text? I mean I tried to look up the issue you mention and couldn't find anything, quite the contrary, e.g. Postgres says SCRAM-SHA-256 is the only recommended scheme for password-based auth and storing passwords in clear text is not possible. Isn't it kind of the point that passwords are never stored in clear text with this scheme? https://www.postgresql.org/docs/13/auth-password.html Erik
[libvirt PATCH 0/2] docs: less docs for insecure SASL mechanisms
GSSAPI and SCRAM-SHA-256 are the only two SASL mechanisms we especially want people to be using. Even the latter is a little questionable due to storing passwords in cleartext on the server. Daniel P. Berrangé (2): docs: convert auth page into RST format docs: stop mentioning insecure / broken SASL mechanisms docs/auth.html.in| 368 --- docs/auth.rst| 323 ++ docs/meson.build | 2 +- src/remote/libvirtd.sasl | 11 +- 4 files changed, 330 insertions(+), 374 deletions(-) delete mode 100644 docs/auth.html.in create mode 100644 docs/auth.rst -- 2.29.2
