Commit Graph

10 Commits

Author SHA1 Message Date
Markus Armbruster a8d2532645 Include qemu-common.h exactly where needed
No header includes qemu-common.h after this commit, as prescribed by
qemu-common.h's file comment.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-5-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
include/hw/arm/xlnx-zynqmp.h hw/arm/nrf51_soc.c hw/arm/msf2-soc.c
block/qcow2-refcount.c block/qcow2-cluster.c block/qcow2-cache.c
target/arm/cpu.h target/lm32/cpu.h target/m68k/cpu.h target/mips/cpu.h
target/moxie/cpu.h target/nios2/cpu.h target/openrisc/cpu.h
target/riscv/cpu.h target/tilegx/cpu.h target/tricore/cpu.h
target/unicore32/cpu.h target/xtensa/cpu.h; bsd-user/main.c and
net/tap-bsd.c fixed up]
2019-06-12 13:20:20 +02:00
Markus Armbruster a8b991b52d Clean up ill-advised or unusual header guards
Leading underscores are ill-advised because such identifiers are
reserved.  Trailing underscores are merely ugly.  Strip both.

Our header guards commonly end in _H.  Normalize the exceptions.

Done with scripts/clean-header-guards.pl.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190315145123.28030-7-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
[Changes to slirp/ dropped, as we're about to spin it off]
2019-05-13 08:58:55 +02:00
Markus Armbruster 58ea30f514 Clean up header guards that don't match their file name
Header guard symbols should match their file name to make guard
collisions less likely.

Cleaned up with scripts/clean-header-guards.pl, followed by some
renaming of new guard symbols picked by the script to better ones.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190315145123.28030-6-armbru@redhat.com>
[Rebase to master: update include/hw/net/ne2000-isa.h]
2019-05-13 08:58:55 +02:00
Daniel P. Berrangé b4682a63f8 filemon: fix watch IDs to avoid potential wraparound issues
Watch IDs are allocated from incrementing a int counter against
the QFileMonitor object. In very long life QEMU processes with
a huge amount of USB MTP activity creating & deleting directories
it is just about conceivable that the int counter can wrap
around. This would result in incorrect behaviour of the file
monitor watch APIs due to clashing watch IDs.

Instead of trying to detect this situation, this patch changes
the way watch IDs are allocated. It is turned into an int64_t
variable where the high 32 bits are set from the underlying
inotify "int" ID. This gives an ID that is guaranteed unique
for the directory as a whole, and we can rely on the kernel
to enforce this. QFileMonitor then sets the low 32 bits from
a per-directory counter.

The USB MTP device only sets watches on the directory as a
whole, not files within, so there is no risk of guest
triggered wrap around on the low 32 bits.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-02 13:52:02 +01:00
Philippe Mathieu-Daudé 063603d43e authz: Use OBJECT_CHECK() on objects
TYPE_QAUTHZ is an abstract object of type TYPE_OBJECT. All other
are children of TYPE_QAUTHZ, thus also objects.

Keep INTERFACE_CHECK() for interfaces, and use OBJECT_CHECK() on
objects.

Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-03-21 11:52:37 +00:00
Daniel P. Berrange 8953caf3cd authz: add QAuthZPAM object type for authorizing using PAM
Add an authorization backend that talks to PAM to check whether the user
identity is allowed. This only uses the PAM account validation facility,
which is essentially just a check to see if the provided username is permitted
access. It doesn't use the authentication or session parts of PAM, since
that's dealt with by the relevant part of QEMU (eg VNC server).

Consider starting QEMU with a VNC server and telling it to use TLS with
x509 client certificates and configuring it to use an PAM to validate
the x509 distinguished name. In this example we're telling it to use PAM
for the QAuthZ impl with a service name of "qemu-vnc"

 $ qemu-system-x86_64 \
     -object tls-creds-x509,id=tls0,dir=/home/berrange/security/qemutls,\
             endpoint=server,verify-peer=yes \
     -object authz-pam,id=authz0,service=qemu-vnc \
     -vnc :1,tls-creds=tls0,tls-authz=authz0

This requires an /etc/pam/qemu-vnc file to be created with the auth
rules. A very simple file based whitelist can be setup using

  $ cat > /etc/pam/qemu-vnc <<EOF
  account         requisite       pam_listfile.so item=user sense=allow file=/etc/qemu/vnc.allow
  EOF

The /etc/qemu/vnc.allow file simply contains one username per line. Any
username not in the file is denied. The usernames in this example are
the x509 distinguished name from the client's x509 cert.

  $ cat > /etc/qemu/vnc.allow <<EOF
  CN=laptop.berrange.com,O=Berrange Home,L=London,ST=London,C=GB
  EOF

More interesting would be to configure PAM to use an LDAP backend, so
that the QEMU authorization check data can be centralized instead of
requiring each compute host to have file maintained.

The main limitation with this PAM module is that the rules apply to all
QEMU instances on the host. Setting up different rules per VM, would
require creating a separate PAM service name & config file for every
guest. An alternative approach for the future might be to not pass in
the plain username to PAM, but instead combine the VM name or UUID with
the username. This requires further consideration though.

Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2019-02-26 15:32:19 +00:00
Daniel P. Berrangé 55d869846d authz: add QAuthZListFile object type for a file access control list
Add a QAuthZListFile object type that implements the QAuthZ interface. This
built-in implementation is a proxy around the QAuthZList object type,
initializing it from an external file, and optionally, automatically
reloading it whenever it changes.

To create an instance of this object via the QMP monitor, the syntax
used would be:

      {
        "execute": "object-add",
        "arguments": {
          "qom-type": "authz-list-file",
          "id": "authz0",
          "props": {
            "filename": "/etc/qemu/vnc.acl",
	    "refresh": true
          }
        }
      }

If "refresh" is "yes", inotify is used to monitor the file,
automatically reloading changes. If an error occurs during reloading,
all authorizations will fail until the file is next successfully
loaded.

The /etc/qemu/vnc.acl file would contain a JSON representation of a
QAuthZList object

    {
      "rules": [
         { "match": "fred", "policy": "allow", "format": "exact" },
         { "match": "bob", "policy": "allow", "format": "exact" },
         { "match": "danb", "policy": "deny", "format": "glob" },
         { "match": "dan*", "policy": "allow", "format": "exact" },
      ],
      "policy": "deny"
    }

This sets up an authorization rule that allows 'fred', 'bob' and anyone
whose name starts with 'dan', except for 'danb'. Everyone unmatched is
denied.

The object can be loaded on the comand line using

   -object authz-list-file,id=authz0,filename=/etc/qemu/vnc.acl,refresh=yes

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-02-26 15:32:18 +00:00
Daniel P. Berrange c8c99887d1 authz: add QAuthZList object type for an access control list
Add a QAuthZList object type that implements the QAuthZ interface. This
built-in implementation maintains a trivial access control list with a
sequence of match rules and a final default policy. This replicates the
functionality currently provided by the qemu_acl module.

To create an instance of this object via the QMP monitor, the syntax
used would be:

  {
    "execute": "object-add",
    "arguments": {
      "qom-type": "authz-list",
      "id": "authz0",
      "props": {
        "rules": [
           { "match": "fred", "policy": "allow", "format": "exact" },
           { "match": "bob", "policy": "allow", "format": "exact" },
           { "match": "danb", "policy": "deny", "format": "glob" },
           { "match": "dan*", "policy": "allow", "format": "exact" },
        ],
        "policy": "deny"
      }
    }
  }

This sets up an authorization rule that allows 'fred', 'bob' and anyone
whose name starts with 'dan', except for 'danb'. Everyone unmatched is
denied.

It is not currently possible to create this via -object, since there is
no syntax supported to specify non-scalar properties for objects. This
is likely to be addressed by later support for using JSON with -object,
or an equivalent approach.

In any case the future "authz-listfile" object can be used from the
CLI and is likely a better choice, as it allows the ACL to be refreshed
automatically on change.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2019-02-26 15:32:18 +00:00
Daniel P. Berrangé fb5c4ebc08 authz: add QAuthZSimple object type for easy whitelist auth checks
In many cases a single VM will just need to whitelist a single identity
as the allowed user of network services. This is especially the case for
TLS live migration (optionally with NBD storage) where we just need to
whitelist the x509 certificate distinguished name of the source QEMU
host.

Via QMP this can be configured with:

  {
    "execute": "object-add",
    "arguments": {
      "qom-type": "authz-simple",
      "id": "authz0",
      "props": {
        "identity": "fred"
      }
    }
  }

Or via the command line

  -object authz-simple,id=authz0,identity=fred

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2019-02-26 15:25:58 +00:00
Daniel P. Berrange 5b76dd132c authz: add QAuthZ object as an authorization base class
The current qemu_acl module provides a simple access control list
facility inside QEMU, which is used via a set of monitor commands
acl_show, acl_policy, acl_add, acl_remove & acl_reset.

Note there is no ability to create ACLs - the network services (eg VNC
server) were expected to create ACLs that they want to check.

There is also no way to define ACLs on the command line, nor potentially
integrate with external authorization systems like polkit, pam, ldap
lookup, etc.

The QAuthZ object defines a minimal abstract QOM class that can be
subclassed for creating different authorization providers.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2019-02-26 15:25:58 +00:00