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Hello Jamers! As part of my work at Linagora, we are looking toward - better integrating James within our product suite and for us this means support "Single Sign On" and "Single Log Out" for JMAP following the OpenId connect standard [0]. - Improving security standards used to opperate James. (We have a growing activity within the health care market, sensible to security arguments) Regarding security standards we should ideally: - Be able to NOT advertise AUTH / LOGIN capabilities of unencrypted channels (Correspond to IMAP plainAuthDissallowed but generalized to other protocols) - Be able to require OAUTH/OIDC authentication for all protocols (IMAP, SMTP, JMAP) - this is what some of the health care providers we spoke to desired to do. - For our collaborative suite usage, while OIDC only for JMAP makes sense, we still wish to maintain PLAIN AUTH for IMAP and SMTP. - Of course settings for regular users not interested in OIDC should not change (no breaking changes, OIDC adoption is opt-in only). As such we propose ourselves to: - Contribute IMAP and SMTP SASL OAUTH extension described in [RFC-7628] - Modularize JMAP authentication mechanisms (letting the admin choose which one she wishes to use) - Enable authentication through a header mechanism eg `X-USER: btell...@apache.org`, which can be used to delegate OIDC authentication through a third party API gateway. We have Krackend [1] in mind. - Share documentation and a docker-compose of OIDC setup for IMAP, SMTP and JMAP in https://github.com/apache/james-project/tree/master/examples/oidc. This would include: - A LDAP still used by James UsersRepository. Provisionned with a testing user. - A pre-configured Keycloack [2] OpenID connect provider. - A pre-configured Krakend API gateway proxying JMAP - And finally a James server configured to only accept OIDC as an authentication mechanism for IMAP, SMTP and JMAP. - Unit tests for existing IMAP `plainAuthDissallowed` configuration parameter. Finally this is a good opportunity to restructure authentication related settings in imapserver.xml and smtpserver.xml file. Here are proposals for both files: [imapserver.xml] ---- <imapserver enabled="true"> <jmxName>imapserver-ssl</jmxName> <bind>0.0.0.0:993</bind> <tls socketTLS="true" startTLS="false"> <privateKey>file://conf/private.key</privateKey> <certificates>file://conf/certs.self-signed.csr</certificates> </tls> <!-- ... --> <authentication> <plainAuthEnabled>true|false</plainAuthEnabled> <!-- defaults to true --> <oauth> <!-- ommiting this block would disable oauth. All fields are compulsory --> <publicKey>file://conf/imapJWT.pub</publicKey> <oidcConfigurationURL>https://example.com/.well-known/openid-config</oidcConfigurationURL> <claim>mailAddress</claim> </oauth> </authentication> </imapserver> ---- [smtpserver.xml] ---- <smtpserver enabled="true"> <jmxName>smtpserver-ssl</jmxName> <bind>0.0.0.0:465</bind> <tls socketTLS="true" startTLS="false"> <privateKey>file://conf/private.key</privateKey> <certificates>file://conf/certs.self-signed.csr</certificates> </tls> <!--- ... --> <requireAuthForRelay>true|false</requireAuthForRelay> <authentication> <plainAuthEnabled>true|false</plainAuthEnabled> <!-- defaults to true --> <oauth> <!-- ommiting this block would disable oauth. All fields are compulsory --> <publicKey>file://conf/imapJWT.pub</publicKey> <oidcConfigurationURL>https://example.com/.well-known/openid-config</oidcConfigurationURL> <claim>mailAddress</claim> </oauth> </authentication> </smtpserver> ---- You can see that: - The `plainAuthDissallowed` parameter is proposed to be renamed to `auth.requireSSL`. (of course we should support fallback NOT to have a breaking change) - `auth.plainAuthEnabled` enable turning on/off plain auth, which allows having OIDC only mechanism. - `auth.requireSSL` will be generalized to SMTP. - In SMTP `requireAuth` setting is very misleading as it rather is `requireAuthForRelay`. I propose we rename this configuration option (of course we should support fallback NOT to have a breaking change). Here is the implementation strategies we would follow: - For JMAP have Krakend doing all the hard job for us, and use a dedicated header to carry the information over to James. - Our code contributions aims at easing such a setup (that would only require configuration) - Provide an informative example using krakend. We understand that this choice is ours, yet sharing it could allow reuse or similar setup - If some people wishes to write an OIDC authentication strategy directly in James then they perfectly can! (Reusing the modularization of JMAP authentication strategies we would provide). - For IMAP and SMTP then we proposes to check the bearer payload against a statically configured public key for these protocols. (Sadly there is no API gateway for those protocols) - Drawbacks includes no revocation of access tokens (once it's signed it is always valid), revocation do not shut down existing connections authenticated with the revocated token, and key rotation would require reconfiguration and reboot. - One alternative would be to systematically ask the OpenID server to validate the bearer. This might be acceptable as IMAP and SMTP are long lived protocols that do not often establish new connections. While this do not change anything regarding already opened connection management, this solves revocation and public key rotation at the price of exposing more the identity provider... - Of course James could expose a back-channel for token invalidation, stored in some kind of shared storage, but this complexify things a bit. - Similarily HTTP calls could be made to get the JWKS key (and cache it) but this also complexify the picture quite a bit... I am deeply convinced this efforts would help James admins more control over exposed authentication mechanisms and ultimately offer state of the art authentication options. This should help James check a few more boxes in security reviews and eventually ease adoption! Useful links: [0] OpenId spec: https://openid.net/specs/openid-connect-core-1_0.html [1] Krakend: https://www.krakend.io/ [2] Keycloack: https://www.keycloak.org/ [RFC-7628] SASL OATH mechanism for SMTP and IMAP: https://datatracker.ietf.org/doc/html/rfc7628 Krakend configured with keycloack: https://www.krakend.io/docs/authorization/keycloak/ Krakend configured with token revocation: https://www.krakend.io/docs/authorization/revoking-tokens/ Best regards, Benoit TELLIER On 02/12/2021 11:41, btell...@apache.org wrote: > |Hello Jamers! As part of our work at Linagora, we are looking toward - > better integrating James within our product suite and for us this means > support "Single Sign On" and "Single Log Out" for JMAP following the > OpenId connect standard [0]. - Improving security standards used to > operate James. (We have a growing activity within the health care > market, sensible to security arguments) Regarding security standards we > should ideally: - Be able to NOT advertise AUTH / LOGIN capabilities of > unencrypted channels (Correspond to IMAP plainAuthDissallowed but > generalized to other protocols) - Be able to require OAUTH/OIDC > authentication for all protocols (IMAP, SMTP, JMAP) - this is what some > of the health care providers we spoke to desired to do. - For our > collaborative suite usage, while OIDC only for JMAP makes sense, we > still wish to maintain PLAIN AUTH for IMAP and SMTP. - Of course > settings for regular users not interested in OIDC should not change (no > breaking changes, OIDC adoption is opt-in only). As such we propose > ourselves to: - Contribute IMAP and SMTP SASL OAUTH extension described > in [RFC-7628] - Modularize JMAP authentication mechanisms (letting the > admin choose which one she wishes to use) - Enable authentication > through a header mechanism eg `X-USER: btell...@apache.org`, which can > be used to delegate OIDC authentication through a third party API > gateway. We have Krackend [1] in mind. - Share documentation and a > docker-compose of OIDC setup for IMAP, SMTP and JMAP in > https://github.com/apache/james-project/tree/master/examples/oidc. This > would include: - A LDAP still used by James UsersRepository. Provisioned > with a testing user. - A pre-configured Keycloack [2] OpenID connect > provider. - A pre-configured Krakend API gateway proxying JMAP - And > finally a James server configured to only accept OIDC as an > authentication mechanism for IMAP, SMTP and JMAP. - Unit tests for > existing IMAP `plainAuthDissallowed` configuration parameter. Finally > this is a good opportunity to restructure authentication related > settings in imapserver.xml and smtpserver.xml file. Here are proposals > for both files: [imapserver.xml] ---- <imapserver enabled="true"> > <jmxName>imapserver-ssl</jmxName> <bind>0.0.0.0:993</bind> <tls > socketTLS="true" startTLS="false"> > <privateKey>file://conf/private.key</privateKey> > <certificates>file://conf/certs.self-signed.csr</certificates> </tls> > <!-- ... --> <authentication> > <plainAuthEnabled>true|false</plainAuthEnabled> <!-- defaults to true > --> <oauth> <!-- ommiting this block would disable oauth. All fields are > compulsory --> <publicKey>file://conf/imapJWT.pub</publicKey> > <oidcConfigurationURL>https://example.com/.well-known/openid-config</oidcConfigurationURL> > <claim>mailAddress</claim> </oauth> </authentication> </imapserver> ---- > [smtpserver.xml] ---- <smtpserver enabled="true"> > <jmxName>smtpserver-ssl</jmxName> <bind>0.0.0.0:465</bind> <tls > socketTLS="true" startTLS="false"> > <privateKey>file://conf/private.key</privateKey> > <certificates>file://conf/certs.self-signed.csr</certificates> </tls> > <!--- ... --> <requireAuthForRelay>true|false</requireAuthForRelay> > <authentication> <plainAuthEnabled>true|false</plainAuthEnabled> <!-- > defaults to true --> <oauth> <!-- ommiting this block would disable > oauth. All fields are compulsory --> > <publicKey>file://conf/imapJWT.pub</publicKey> > <oidcConfigurationURL>https://example.com/.well-known/openid-config</oidcConfigurationURL> > <claim>mailAddress</claim> </oauth> </authentication> </smtpserver> ---- > You can see that: - The `plainAuthDissallowed` parameter is proposed to > be renamed to `auth.requireSSL`. (of course we should support fallback > NOT to have a breaking change) - `auth.plainAuthEnabled` enable turning > on/off plain auth, which allows having OIDC only mechanism. - > `auth.requireSSL` will be generalized to SMTP. - In SMTP `requireAuth` > setting is very misleading as it rather is `requireAuthForRelay`. I > propose we rename this configuration option (of course we should support > fallback NOT to have a breaking change). Here is the implementation > strategies we would follow: - For JMAP have Krakend doing all the hard > job for us, and use a dedicated header to carry the information over to > James. - Our code contributions aims at easing such a setup (that would > only require configuration) - Provide an informative example using > krakend. We understand that this choice is ours, yet sharing it could > allow reuse or similar setup - If some people wishes to write an OIDC > authentication strategy directly in James then they perfectly can! > (Reusing the modularization of JMAP authentication strategies we would > provide). - For IMAP and SMTP then we proposes to check the bearer > payload against a statically configured public key for these protocols. > (Sadly there is no API gateway for those protocols) - Drawbacks includes > no revocation of access tokens (once it's signed it is always valid), > revocation do not shut down existing connections authenticated with the > revocated token, and key rotation would require reconfiguration and > reboot. - One alternative would be to systematically ask the OpenID > server to validate the bearer. This might be acceptable as IMAP and SMTP > are long lived protocols that do not often establish new connections. > While this do not change anything regarding already opened connection > management, this solves revocation and public key rotation at the price > of exposing more the identity provider... - Of course James could expose > a back-channel for token invalidation, stored in some kind of shared > storage, but this complexify things a bit. - Similarily HTTP calls could > be made to get the JWKS key (and cache it) but this also complexify the > picture quite a bit... I am deeply convinced this efforts would help > James admins more control over exposed authentication mechanisms and > ultimately offer state of the art authentication options. This should > help James check a few more boxes in security reviews and eventually > ease adoption! Useful links: [0] OpenId spec: > https://openid.net/specs/openid-connect-core-1_0.html [1] Krakend: > https://www.krakend.io/ [2] Keycloack: https://www.keycloak.org/ > [RFC-7628] SASL OATH mechanism for SMTP and IMAP: > https://datatracker.ietf.org/doc/html/rfc7628 Krakend configured with > keycloack: https://www.krakend.io/docs/authorization/keycloak/ Krakend > configured with token revocation: > https://www.krakend.io/docs/authorization/revoking-tokens/ Best regards, > Benoit TELLIER| > > --------------------------------------------------------------------- To unsubscribe, e-mail: server-dev-unsubscr...@james.apache.org For additional commands, e-mail: server-dev-h...@james.apache.org
