Files
snapd/daemon/access_test.go
2024-04-03 13:26:36 +02:00

425 lines
16 KiB
Go

// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2021-2024 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package daemon_test
import (
"fmt"
"net/http"
"net/http/httptest"
. "gopkg.in/check.v1"
"github.com/snapcore/snapd/client"
"github.com/snapcore/snapd/daemon"
"github.com/snapcore/snapd/dirs"
"github.com/snapcore/snapd/logger"
"github.com/snapcore/snapd/overlord/auth"
"github.com/snapcore/snapd/polkit"
"github.com/snapcore/snapd/testutil"
)
type accessSuite struct {
apiBaseSuite
}
var _ = Suite(&accessSuite{})
var (
errForbidden = daemon.Forbidden("access denied")
errUnauthorized = daemon.Unauthorized("access denied")
)
func (s *accessSuite) TestOpenAccess(c *C) {
var ac daemon.AccessChecker = daemon.OpenAccess{}
// openAccess denies access from snapd-snap.socket
ucred := &daemon.Ucrednet{Uid: 42, Pid: 100, Socket: dirs.SnapSocket}
c.Check(ac.CheckAccess(nil, nil, ucred, nil), DeepEquals, errForbidden)
// Access allowed from snapd.socket
ucred.Socket = dirs.SnapdSocket
c.Check(ac.CheckAccess(nil, nil, ucred, nil), IsNil)
// Access forbidden without peer credentials. This will need
// to be revisited if the API is ever exposed over TCP.
c.Check(ac.CheckAccess(nil, nil, nil, nil), DeepEquals, errForbidden)
}
func (s *accessSuite) TestAuthenticatedAccess(c *C) {
restore := daemon.MockCheckPolkitAction(func(r *http.Request, ucred *daemon.Ucrednet, action string) *daemon.APIError {
// Polkit is not consulted if no action is specified
c.Fail()
return daemon.Forbidden("access denied")
})
defer restore()
var ac daemon.AccessChecker = daemon.AuthenticatedAccess{}
req := httptest.NewRequest("GET", "/", nil)
user := &auth.UserState{}
// authenticatedAccess denies access from snapd-snap.socket
ucred := &daemon.Ucrednet{Uid: 0, Pid: 100, Socket: dirs.SnapSocket}
c.Check(ac.CheckAccess(nil, req, ucred, nil), DeepEquals, errForbidden)
c.Check(ac.CheckAccess(nil, req, ucred, user), DeepEquals, errForbidden)
// the same for unknown sockets
ucred = &daemon.Ucrednet{Uid: 0, Pid: 100, Socket: "unexpected.socket"}
c.Check(ac.CheckAccess(nil, req, ucred, nil), DeepEquals, errForbidden)
// With macaroon auth, a normal user is granted access
ucred = &daemon.Ucrednet{Uid: 42, Pid: 100, Socket: dirs.SnapdSocket}
c.Check(ac.CheckAccess(nil, req, ucred, user), IsNil)
// Macaroon access requires peer credentials
c.Check(ac.CheckAccess(nil, req, nil, user), DeepEquals, errForbidden)
// Without macaroon auth, normal users are unauthorized
c.Check(ac.CheckAccess(nil, req, ucred, nil), DeepEquals, errUnauthorized)
// The root user is granted access without a macaroon
ucred = &daemon.Ucrednet{Uid: 0, Pid: 100, Socket: dirs.SnapdSocket}
c.Check(ac.CheckAccess(nil, req, ucred, nil), IsNil)
}
func (s *accessSuite) TestAuthenticatedAccessPolkit(c *C) {
var ac daemon.AccessChecker = daemon.AuthenticatedAccess{Polkit: "action-id"}
req := httptest.NewRequest("GET", "/", nil)
user := &auth.UserState{}
ucred := &daemon.Ucrednet{Uid: 0, Pid: 100, Socket: dirs.SnapdSocket}
// polkit is not checked if any of:
// * ucred is missing
// * macaroon auth is provided
// * user is root
restore := daemon.MockCheckPolkitAction(func(r *http.Request, ucred *daemon.Ucrednet, action string) *daemon.APIError {
c.Fail()
return daemon.Forbidden("access denied")
})
defer restore()
c.Check(ac.CheckAccess(nil, req, nil, nil), DeepEquals, errForbidden)
c.Check(ac.CheckAccess(nil, req, nil, user), DeepEquals, errForbidden)
c.Check(ac.CheckAccess(nil, req, ucred, nil), IsNil)
// polkit is checked for regular users without macaroon auth
restore = daemon.MockCheckPolkitAction(func(r *http.Request, u *daemon.Ucrednet, action string) *daemon.APIError {
c.Check(r, Equals, req)
c.Check(u, Equals, ucred)
c.Check(action, Equals, "action-id")
return nil
})
defer restore()
ucred = &daemon.Ucrednet{Uid: 42, Pid: 100, Socket: dirs.SnapdSocket}
c.Check(ac.CheckAccess(nil, req, ucred, nil), IsNil)
}
func (s *accessSuite) TestCheckPolkitActionImpl(c *C) {
logbuf, restore := logger.MockLogger()
defer restore()
req := httptest.NewRequest("GET", "/", nil)
ucred := &daemon.Ucrednet{Uid: 42, Pid: 1000, Socket: dirs.SnapdSocket}
// Access granted if polkit authorizes the request
restore = daemon.MockPolkitCheckAuthorization(func(pid int32, uid uint32, actionId string, details map[string]string, flags polkit.CheckFlags) (bool, error) {
c.Check(pid, Equals, int32(1000))
c.Check(uid, Equals, uint32(42))
c.Check(actionId, Equals, "action-id")
c.Check(details, IsNil)
c.Check(flags, Equals, polkit.CheckFlags(0))
return true, nil
})
defer restore()
c.Check(daemon.CheckPolkitActionImpl(req, ucred, "action-id"), IsNil)
c.Check(logbuf.String(), Equals, "")
// Unauthorized if polkit denies the request
restore = daemon.MockPolkitCheckAuthorization(func(pid int32, uid uint32, actionId string, details map[string]string, flags polkit.CheckFlags) (bool, error) {
return false, nil
})
defer restore()
c.Check(daemon.CheckPolkitActionImpl(req, ucred, "action-id"), DeepEquals, errUnauthorized)
c.Check(logbuf.String(), Equals, "")
// Cancelled if the user dismisses the auth check
restore = daemon.MockPolkitCheckAuthorization(func(pid int32, uid uint32, actionId string, details map[string]string, flags polkit.CheckFlags) (bool, error) {
return false, polkit.ErrDismissed
})
defer restore()
rspe := daemon.CheckPolkitActionImpl(req, ucred, "action-id")
c.Check(rspe, DeepEquals, daemon.AuthCancelled("cancelled"))
c.Check(logbuf.String(), Equals, "")
// The X-Allow-Interaction header can be set to tell polkitd
// that interaction with the user is allowed.
req.Header.Set(client.AllowInteractionHeader, "true")
restore = daemon.MockPolkitCheckAuthorization(func(pid int32, uid uint32, actionId string, details map[string]string, flags polkit.CheckFlags) (bool, error) {
c.Check(flags, Equals, polkit.CheckFlags(polkit.CheckAllowInteraction))
return true, nil
})
defer restore()
c.Check(daemon.CheckPolkitActionImpl(req, ucred, "action-id"), IsNil)
c.Check(logbuf.String(), Equals, "")
// Bad values in the request header are logged
req.Header.Set(client.AllowInteractionHeader, "garbage")
restore = daemon.MockPolkitCheckAuthorization(func(pid int32, uid uint32, actionId string, details map[string]string, flags polkit.CheckFlags) (bool, error) {
c.Check(flags, Equals, polkit.CheckFlags(0))
return true, nil
})
defer restore()
c.Check(daemon.CheckPolkitActionImpl(req, ucred, "action-id"), IsNil)
c.Check(logbuf.String(), testutil.Contains, "error parsing X-Allow-Interaction header:")
}
func (s *accessSuite) TestRootAccess(c *C) {
var ac daemon.AccessChecker = daemon.RootAccess{}
user := &auth.UserState{}
// rootAccess denies access without ucred
c.Check(ac.CheckAccess(nil, nil, nil, nil), DeepEquals, errForbidden)
c.Check(ac.CheckAccess(nil, nil, nil, user), DeepEquals, errForbidden)
// rootAccess denies access from snapd-snap.socket
ucred := &daemon.Ucrednet{Uid: 0, Pid: 100, Socket: dirs.SnapSocket}
c.Check(ac.CheckAccess(nil, nil, ucred, nil), DeepEquals, errForbidden)
c.Check(ac.CheckAccess(nil, nil, ucred, user), DeepEquals, errForbidden)
// Non-root users are forbidden, even with macaroon auth
ucred = &daemon.Ucrednet{Uid: 42, Pid: 100, Socket: dirs.SnapdSocket}
c.Check(ac.CheckAccess(nil, nil, ucred, nil), DeepEquals, errForbidden)
c.Check(ac.CheckAccess(nil, nil, ucred, user), DeepEquals, errForbidden)
// Root is granted access
ucred = &daemon.Ucrednet{Uid: 0, Pid: 100, Socket: dirs.SnapdSocket}
c.Check(ac.CheckAccess(nil, nil, ucred, nil), IsNil)
}
func (s *accessSuite) TestSnapAccess(c *C) {
var ac daemon.AccessChecker = daemon.SnapAccess{}
// snapAccess allows access from snapd-snap.socket
ucred := &daemon.Ucrednet{Uid: 42, Pid: 100, Socket: dirs.SnapSocket}
c.Check(ac.CheckAccess(nil, nil, ucred, nil), IsNil)
// access is forbidden on the main socket or without peer creds
ucred.Socket = dirs.SnapdSocket
c.Check(ac.CheckAccess(nil, nil, ucred, nil), DeepEquals, errForbidden)
c.Check(ac.CheckAccess(nil, nil, nil, nil), DeepEquals, errForbidden)
}
func (s *accessSuite) TestRequireInterfaceApiAccessImpl(c *C) {
d := s.daemon(c)
s.mockSnap(c, `
name: core
type: os
version: 1
slots:
snap-themes-control:
snap-refresh-control:
`)
s.mockSnap(c, `
name: some-snap
version: 1
plugs:
snap-themes-control:
snap-refresh-control:
`)
restore := daemon.MockCgroupSnapNameFromPid(func(pid int) (string, error) {
if pid == 42 {
return "some-snap", nil
}
return "", fmt.Errorf("not a snap")
})
defer restore()
var ac daemon.AccessChecker = daemon.InterfaceOpenAccess{Interfaces: []string{"snap-themes-control", "snap-refresh-control"}}
// Access with no ucred data is forbidden
c.Check(ac.CheckAccess(d, nil, nil, nil), DeepEquals, errForbidden)
// Access from snapd.socket is allowed
ucred := &daemon.Ucrednet{Uid: 1000, Pid: 1001, Socket: dirs.SnapdSocket}
req := http.Request{RemoteAddr: ucred.String()}
c.Check(ac.CheckAccess(d, nil, ucred, nil), IsNil)
c.Check(req.RemoteAddr, Equals, ucred.String())
// Access from unknown sockets is forbidden
ucred = &daemon.Ucrednet{Uid: 1000, Pid: 1001, Socket: "unknown.socket"}
c.Check(ac.CheckAccess(d, nil, ucred, nil), DeepEquals, errForbidden)
// Access from pids that cannot be mapped to a snap on
// snapd-snap.socket are rejected
ucred = &daemon.Ucrednet{Uid: 1000, Pid: 1001, Socket: dirs.SnapSocket}
c.Check(ac.CheckAccess(d, nil, ucred, nil), DeepEquals, daemon.Forbidden("could not determine snap name for pid: not a snap"))
// Access from snapd-snap.socket is rejected by default
ucred = &daemon.Ucrednet{Uid: 1000, Pid: 42, Socket: dirs.SnapSocket}
c.Check(ac.CheckAccess(d, nil, ucred, nil), DeepEquals, errForbidden)
// Now connect the marker interface
st := d.Overlord().State()
st.Lock()
st.Set("conns", map[string]interface{}{
"some-snap:snap-themes-control core:snap-themes-control": map[string]interface{}{
"interface": "snap-themes-control",
},
})
st.Unlock()
// Access is allowed now that the snap has the plug connected
req = http.Request{RemoteAddr: ucred.String()}
c.Check(ac.CheckAccess(s.d, &req, ucred, nil), IsNil)
// Interface is attached to RemoteAddr
c.Check(req.RemoteAddr, Equals, fmt.Sprintf("%siface=snap-themes-control;", ucred))
// Now connect both interfaces
st.Lock()
st.Set("conns", map[string]interface{}{
"some-snap:snap-themes-control core:snap-themes-control": map[string]interface{}{
"interface": "snap-themes-control",
},
"some-snap:snap-refresh-control core:snap-refresh-control": map[string]interface{}{
"interface": "snap-refresh-control",
},
})
st.Unlock()
req = http.Request{RemoteAddr: ucred.String()}
c.Check(ac.CheckAccess(s.d, &req, ucred, nil), IsNil)
// Check that both interfaces are attached to RemoteAddr.
// Since conns is a map, order is not guaranteed.
c.Check(req.RemoteAddr, Matches, fmt.Sprintf("^%siface=(snap-themes-control&snap-refresh-control|snap-refresh-control&snap-themes-control);$", ucred))
// A left over "undesired" connection does not grant access
st.Lock()
st.Set("conns", map[string]interface{}{
"some-snap:snap-themes-control core:snap-themes-control": map[string]interface{}{
"interface": "snap-themes-control",
"undesired": true,
},
})
st.Unlock()
req = http.Request{RemoteAddr: ucred.String()}
c.Check(ac.CheckAccess(d, nil, ucred, nil), DeepEquals, errForbidden)
c.Check(req.RemoteAddr, Equals, ucred.String())
}
func (s *accessSuite) TestInterfaceOpenAccess(c *C) {
var ac daemon.AccessChecker = daemon.InterfaceOpenAccess{Interfaces: []string{"snap-themes-control"}}
s.daemon(c)
// interfaceOpenAccess allows access if requireInterfaceApiAccess() succeeds
ucred := &daemon.Ucrednet{Uid: 42, Pid: 100, Socket: dirs.SnapSocket}
restore := daemon.MockRequireInterfaceApiAccess(func(d *daemon.Daemon, r *http.Request, u *daemon.Ucrednet, interfaceNames []string) *daemon.APIError {
c.Check(d, Equals, s.d)
c.Check(u, Equals, ucred)
return nil
})
defer restore()
c.Check(ac.CheckAccess(s.d, nil, ucred, nil), IsNil)
// Access is forbidden if requireInterfaceApiAccess() fails
restore = daemon.MockRequireInterfaceApiAccess(func(d *daemon.Daemon, r *http.Request, u *daemon.Ucrednet, interfaceNames []string) *daemon.APIError {
return errForbidden
})
defer restore()
c.Check(ac.CheckAccess(s.d, nil, ucred, nil), DeepEquals, errForbidden)
}
func (s *accessSuite) TestInterfaceAuthenticatedAccess(c *C) {
restore := daemon.MockCheckPolkitAction(func(r *http.Request, ucred *daemon.Ucrednet, action string) *daemon.APIError {
// Polkit is not consulted if no action is specified
c.Fail()
return errForbidden
})
defer restore()
var ac daemon.AccessChecker = daemon.InterfaceAuthenticatedAccess{}
req := httptest.NewRequest("GET", "/", nil)
user := &auth.UserState{}
s.daemon(c)
// themesAuthenticatedAccess denies access if requireInterfaceApiAccess fails
ucred := &daemon.Ucrednet{Uid: 0, Pid: 100, Socket: dirs.SnapSocket}
restore = daemon.MockRequireInterfaceApiAccess(func(d *daemon.Daemon, r *http.Request, u *daemon.Ucrednet, interfaceNames []string) *daemon.APIError {
c.Check(d, Equals, s.d)
c.Check(u, Equals, ucred)
return errForbidden
})
defer restore()
c.Check(ac.CheckAccess(s.d, req, ucred, nil), DeepEquals, errForbidden)
c.Check(ac.CheckAccess(s.d, req, ucred, user), DeepEquals, errForbidden)
// If requireInterfaceApiAccess succeeds, root is granted access
restore = daemon.MockRequireInterfaceApiAccess(func(d *daemon.Daemon, r *http.Request, u *daemon.Ucrednet, interfaceNames []string) *daemon.APIError {
return nil
})
defer restore()
c.Check(ac.CheckAccess(s.d, req, ucred, nil), IsNil)
// Macaroon auth will grant a normal user access too
ucred = &daemon.Ucrednet{Uid: 42, Pid: 100, Socket: dirs.SnapSocket}
c.Check(ac.CheckAccess(s.d, req, ucred, user), IsNil)
// Without macaroon auth, normal users are unauthorized
c.Check(ac.CheckAccess(s.d, req, ucred, nil), DeepEquals, errUnauthorized)
}
func (s *accessSuite) TestInterfaceAuthenticatedAccessPolkit(c *C) {
var ac daemon.AccessChecker = daemon.InterfaceAuthenticatedAccess{Polkit: "action-id"}
req := httptest.NewRequest("GET", "/", nil)
user := &auth.UserState{}
ucred := &daemon.Ucrednet{Uid: 0, Pid: 100, Socket: dirs.SnapSocket}
s.daemon(c)
restore := daemon.MockRequireInterfaceApiAccess(func(d *daemon.Daemon, r *http.Request, u *daemon.Ucrednet, interfaceNames []string) *daemon.APIError {
c.Check(d, Equals, s.d)
c.Check(u, Equals, ucred)
return nil
})
defer restore()
// polkit is not checked if any of:
// * user is root
// * regular users with macaroon auth
restore = daemon.MockCheckPolkitAction(func(r *http.Request, ucred *daemon.Ucrednet, action string) *daemon.APIError {
c.Fail()
return errForbidden
})
defer restore()
c.Check(ac.CheckAccess(s.d, req, ucred, nil), IsNil)
ucred = &daemon.Ucrednet{Uid: 42, Pid: 100, Socket: dirs.SnapdSocket}
c.Check(ac.CheckAccess(s.d, req, ucred, user), IsNil)
// polkit is checked for regular users without macaroon auth
restore = daemon.MockCheckPolkitAction(func(r *http.Request, u *daemon.Ucrednet, action string) *daemon.APIError {
c.Check(r, Equals, req)
c.Check(u, Equals, ucred)
c.Check(action, Equals, "action-id")
return nil
})
defer restore()
c.Check(ac.CheckAccess(s.d, req, ucred, nil), IsNil)
}