[libvirt] [PATCH 0/2] ui: support for authorization control on TLS connections
This series provides the VNC parts of the authorization control series previously posted as: v1: https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg04482.html v2: https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg05727.html v3: https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg01639.html v4: https://lists.gnu.org/archive/html/qemu-devel/2019-02/msg04319.html The core authz framework is now merged & these patches have all had positive review. Thus these VNC parts are ready to go into the VNC maintainer's tree, should the maintainer consider them acceptable. Note the 2nd patch is modifying the HMP, but I considered it part of ui/vnc, since that's the only bit of QEMU which ever used these HMP commands, and it has a dependancy on the first patch merging first. Daniel P. Berrangé (2): vnc: allow specifying a custom authorization object name monitor: deprecate acl_show, acl_reset, acl_policy, acl_add, acl_remove monitor.c | 23 ++++++++++++++++++ qemu-deprecated.texi | 11 +++++++++ qemu-options.hx | 35 ++++++++++++++++++-------- ui/vnc.c | 58 +++++++++++++++++++++++++++++++++++++------- 4 files changed, 108 insertions(+), 19 deletions(-) -- 2.20.1
From: "Daniel P. Berrange" <berrange@redhat.com> The VNC server has historically had support for ACLs to check both the SASL username and the TLS x509 distinguished name. The VNC server was responsible for creating the initial ACL, and the client app was then responsible for populating it with rules using the HMP 'acl_add' command. This is not satisfactory for a variety of reasons. There is no way to populate the ACLs from the command line, users are forced to use the HMP. With multiple network services all supporting TLS and ACLs now, it is desirable to be able to define a single ACL that is referenced by all services. To address these limitations, two new options are added to the VNC server CLI. The 'tls-authz' option takes the ID of a QAuthZ object to use for checking TLS x509 distinguished names, and the 'sasl-authz' option takes the ID of another object to use for checking SASL usernames. In this example, we setup two authorization rules. The first allows any client with a certificate issued by the 'RedHat' organization in the 'London' locality. The second ACL allows clients with either the 'joe@REDHAT.COM' or 'fred@REDHAT.COM' kerberos usernames. Both checks must pass for the user to be allowed. $QEMU -object tls-creds-x509,id=tls0,dir=/home/berrange/qemutls,\ endpoint=server,verify-peer=yes \ -object authz-simple,id=authz0,policy=deny,\ rules.0.match=O=RedHat,,L=London,rules.0.policy=allow \ -object authz-simple,id=authz1,policy=deny,\ rules.0.match=fred@REDHAT.COM,rules.0.policy=allow \ rules.0.match=joe@REDHAT.COM,rules.0.policy=allow \ -vnc 0.0.0.0:1,tls-creds=tls0,tls-authz=authz0, sasl,sasl-authz=authz1 \ ...other QEMU args... Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com> --- qemu-deprecated.texi | 5 ++++ qemu-options.hx | 35 ++++++++++++++++++-------- ui/vnc.c | 58 +++++++++++++++++++++++++++++++++++++------- 3 files changed, 79 insertions(+), 19 deletions(-) diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi index 45c57952da..1258da4795 100644 --- a/qemu-deprecated.texi +++ b/qemu-deprecated.texi @@ -60,6 +60,11 @@ Support for invalid topologies will be removed, the user must ensure topologies described with -smp include all possible cpus, i.e. @math{@var{sockets} * @var{cores} * @var{threads} = @var{maxcpus}}. +@subsection -vnc acl (since 4.0.0) + +The @code{acl} option to the @code{-vnc} argument has been replaced +by the @code{tls-authz} and @code{sasl-authz} options. + @section QEMU Machine Protocol (QMP) commands @subsection block-dirty-bitmap-add "autoload" parameter (since 2.12.0) diff --git a/qemu-options.hx b/qemu-options.hx index 1cf9aac1fe..c74f99b265 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -1624,6 +1624,14 @@ will cause the VNC server socket to enable the VeNCrypt auth mechanism. The credentials should have been previously created using the @option{-object tls-creds} argument. +@item tls-authz=@var{ID} + +Provides the ID of the QAuthZ authorization object against which +the client's x509 distinguished name will validated. This object is +only resolved at time of use, so can be deleted and recreated on the +fly while the VNC server is active. If missing, it will default +to denying access. + @item sasl Require that the client use SASL to authenticate with the VNC server. @@ -1639,18 +1647,25 @@ ensures a data encryption preventing compromise of authentication credentials. See the @ref{vnc_security} section for details on using SASL authentication. +@item sasl-authz=@var{ID} + +Provides the ID of the QAuthZ authorization object against which +the client's SASL username will validated. This object is +only resolved at time of use, so can be deleted and recreated on the +fly while the VNC server is active. If missing, it will default +to denying access. + @item acl -Turn on access control lists for checking of the x509 client certificate -and SASL party. For x509 certs, the ACL check is made against the -certificate's distinguished name. This is something that looks like -@code{C=GB,O=ACME,L=Boston,CN=bob}. For SASL party, the ACL check is -made against the username, which depending on the SASL plugin, may -include a realm component, eg @code{bob} or @code{bob@@EXAMPLE.COM}. -When the @option{acl} flag is set, the initial access list will be -empty, with a @code{deny} policy. Thus no one will be allowed to -use the VNC server until the ACLs have been loaded. This can be -achieved using the @code{acl} monitor command. +Legacy method for enabling authorization of clients against the +x509 distinguished name and SASL username. It results in the creation +of two @code{authz-list} objects with IDs of @code{vnc.username} and +@code{vnc.x509dname}. The rules for these objects must be configured +with the HMP ACL commands. + +This option is deprecated and should no longer be used. The new +@option{sasl-authz} and @option{tls-authz} options are a +replacement. @item lossy diff --git a/ui/vnc.c b/ui/vnc.c index da4a21d4ce..15d6d2c5d3 100644 --- a/ui/vnc.c +++ b/ui/vnc.c @@ -3357,6 +3357,12 @@ static QemuOptsList qemu_vnc_opts = { },{ .name = "acl", .type = QEMU_OPT_BOOL, + },{ + .name = "tls-authz", + .type = QEMU_OPT_STRING, + },{ + .name = "sasl-authz", + .type = QEMU_OPT_STRING, },{ .name = "lossy", .type = QEMU_OPT_BOOL, @@ -3796,6 +3802,8 @@ void vnc_display_open(const char *id, Error **errp) const char *credid; bool sasl = false; int acl = 0; + const char *tlsauthz; + const char *saslauthz; int lock_key_sync = 1; int key_delay_ms; @@ -3867,7 +3875,33 @@ void vnc_display_open(const char *id, Error **errp) goto fail; } } + if (qemu_opt_get(opts, "acl")) { + error_report("The 'acl' option to -vnc is deprecated. " + "Please use the 'tls-authz' and 'sasl-authz' " + "options instead"); + } acl = qemu_opt_get_bool(opts, "acl", false); + tlsauthz = qemu_opt_get(opts, "tls-authz"); + if (acl && tlsauthz) { + error_setg(errp, "'acl' option is mutually exclusive with the " + "'tls-authz' option"); + goto fail; + } + if (tlsauthz && !vd->tlscreds) { + error_setg(errp, "'tls-authz' provided but TLS is not enabled"); + goto fail; + } + + saslauthz = qemu_opt_get(opts, "sasl-authz"); + if (acl && saslauthz) { + error_setg(errp, "'acl' option is mutually exclusive with the " + "'sasl-authz' option"); + goto fail; + } + if (saslauthz && !sasl) { + error_setg(errp, "'sasl-authz' provided but SASL auth is not enabled"); + goto fail; + } share = qemu_opt_get(opts, "share"); if (share) { @@ -3897,7 +3931,9 @@ void vnc_display_open(const char *id, Error **errp) vd->non_adaptive = true; } - if (acl) { + if (tlsauthz) { + vd->tlsauthzid = g_strdup(tlsauthz); + } else if (acl) { if (strcmp(vd->id, "default") == 0) { vd->tlsauthzid = g_strdup("vnc.x509dname"); } else { @@ -3908,15 +3944,19 @@ void vnc_display_open(const char *id, Error **errp) &error_abort)); } #ifdef CONFIG_VNC_SASL - if (acl && sasl) { - if (strcmp(vd->id, "default") == 0) { - vd->sasl.authzid = g_strdup("vnc.username"); - } else { - vd->sasl.authzid = g_strdup_printf("vnc.%s.username", vd->id); + if (sasl) { + if (saslauthz) { + vd->sasl.authzid = g_strdup(saslauthz); + } else if (acl) { + if (strcmp(vd->id, "default") == 0) { + vd->sasl.authzid = g_strdup("vnc.username"); + } else { + vd->sasl.authzid = g_strdup_printf("vnc.%s.username", vd->id); + } + vd->sasl.authz = QAUTHZ(qauthz_list_new(vd->sasl.authzid, + QAUTHZ_LIST_POLICY_DENY, + &error_abort)); } - vd->sasl.authz = QAUTHZ(qauthz_list_new(vd->sasl.authzid, - QAUTHZ_LIST_POLICY_DENY, - &error_abort)); } #endif -- 2.20.1
The various ACL related commands are obsolete now that the QAuthZ framework for authorization is fully integrated throughout QEMU network services. These only ever worked with VNC and were never used by libvirt. Mark it as deprecated with no direct replacement to be provided. Authorization is now provided by using 'object_add' together with the 'tls-authz' or 'sasl-authz' parameters to the VNC server, and equivalent for other network services. Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> --- monitor.c | 23 +++++++++++++++++++++++ qemu-deprecated.texi | 6 ++++++ 2 files changed, 29 insertions(+) diff --git a/monitor.c b/monitor.c index defa129319..72061d5bae 100644 --- a/monitor.c +++ b/monitor.c @@ -2032,6 +2032,19 @@ static QAuthZList *find_auth(Monitor *mon, const char *name) return QAUTHZ_LIST(obj); } +static bool warn_acl; +static void hmp_warn_acl(void) +{ + if (warn_acl) { + return; + } + error_report("The acl_show, acl_reset, acl_policy, acl_add, acl_remove " + "commands are deprecated with no replacement. Authorization " + "for VNC should be performed using the pluggable QAuthZ " + "objects"); + warn_acl = true; +} + static void hmp_acl_show(Monitor *mon, const QDict *qdict) { const char *aclname = qdict_get_str(qdict, "aclname"); @@ -2039,6 +2052,8 @@ static void hmp_acl_show(Monitor *mon, const QDict *qdict) QAuthZListRuleList *rules; size_t i = 0; + hmp_warn_acl(); + if (!auth) { return; } @@ -2062,6 +2077,8 @@ static void hmp_acl_reset(Monitor *mon, const QDict *qdict) const char *aclname = qdict_get_str(qdict, "aclname"); QAuthZList *auth = find_auth(mon, aclname); + hmp_warn_acl(); + if (!auth) { return; } @@ -2080,6 +2097,8 @@ static void hmp_acl_policy(Monitor *mon, const QDict *qdict) int val; Error *err = NULL; + hmp_warn_acl(); + if (!auth) { return; } @@ -2124,6 +2143,8 @@ static void hmp_acl_add(Monitor *mon, const QDict *qdict) QAuthZListFormat format; size_t i = 0; + hmp_warn_acl(); + if (!auth) { return; } @@ -2169,6 +2190,8 @@ static void hmp_acl_remove(Monitor *mon, const QDict *qdict) QAuthZList *auth = find_auth(mon, aclname); ssize_t i = 0; + hmp_warn_acl(); + if (!auth) { return; } diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi index 1258da4795..1e15f57e9c 100644 --- a/qemu-deprecated.texi +++ b/qemu-deprecated.texi @@ -104,6 +104,12 @@ The @option{[hub_id name]} parameter tuple of the 'hostfwd_add' and Use ``device_add'' for hotplugging vCPUs instead of ``cpu-add''. See documentation of ``query-hotpluggable-cpus'' for additional details. +@subsection acl_show, acl_reset, acl_policy, acl_add, acl_remove (since 4.0.0) + +The ``acl_show'', ``acl_reset'', ``acl_policy'', ``acl_add'', and +``acl_remove'' commands are deprecated with no replacement. Authorization +for VNC should be performed using the pluggable QAuthZ objects. + @section System emulator devices @subsection bluetooth (since 3.1) -- 2.20.1
ping - soft freeze is less than a week away & i'd like this to get into a ui queue pull request in time for 4.0 if there's no review objections On Wed, Feb 27, 2019 at 02:57:53PM +0000, Daniel P. Berrangé wrote:
This series provides the VNC parts of the authorization control series previously posted as:
v1: https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg04482.html v2: https://lists.gnu.org/archive/html/qemu-devel/2018-06/msg05727.html v3: https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg01639.html v4: https://lists.gnu.org/archive/html/qemu-devel/2019-02/msg04319.html
The core authz framework is now merged & these patches have all had positive review. Thus these VNC parts are ready to go into the VNC maintainer's tree, should the maintainer consider them acceptable.
Note the 2nd patch is modifying the HMP, but I considered it part of ui/vnc, since that's the only bit of QEMU which ever used these HMP commands, and it has a dependancy on the first patch merging first.
Daniel P. Berrangé (2): vnc: allow specifying a custom authorization object name monitor: deprecate acl_show, acl_reset, acl_policy, acl_add, acl_remove
monitor.c | 23 ++++++++++++++++++ qemu-deprecated.texi | 11 +++++++++ qemu-options.hx | 35 ++++++++++++++++++-------- ui/vnc.c | 58 +++++++++++++++++++++++++++++++++++++------- 4 files changed, 108 insertions(+), 19 deletions(-)
-- 2.20.1
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 :|
On Thu, Mar 07, 2019 at 12:23:58PM +0000, Daniel P. Berrangé wrote:
ping - soft freeze is less than a week away & i'd like this to get into a ui queue pull request in time for 4.0 if there's no review objections
I'm aware, I'm busy preparing the pre-freeze pulls. USB is on the list already, busy with UI right now. VGA comes next. Series queued. cheers, Gerd
On Thu, Mar 07, 2019 at 02:27:30PM +0100, Gerd Hoffmann wrote:
On Thu, Mar 07, 2019 at 12:23:58PM +0000, Daniel P. Berrangé wrote:
ping - soft freeze is less than a week away & i'd like this to get into a ui queue pull request in time for 4.0 if there's no review objections
I'm aware, I'm busy preparing the pre-freeze pulls. USB is on the list already, busy with UI right now. VGA comes next.
Series queued.
Thanks for the quick reply ! 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 :|
participants (2)
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Daniel P. Berrangé -
Gerd Hoffmann