You've already forked runc
mirror of
https://github.com/opencontainers/runc.git
synced 2025-07-30 17:43:06 +03:00
24388be71e
Making them the same type is simply confusing, but also means that you could accidentally use one in the wrong context. This eliminates that problem. This also includes a whole bunch of cleanups for the types within DeviceRule, so that they can be used more ergonomically. Signed-off-by: Aleksa Sarai <asarai@suse.de>
71 lines
2.1 KiB
Go
71 lines
2.1 KiB
Go
// +build linux
|
|
|
|
package fs2
|
|
|
|
import (
|
|
"github.com/opencontainers/runc/libcontainer/cgroups/ebpf"
|
|
"github.com/opencontainers/runc/libcontainer/cgroups/ebpf/devicefilter"
|
|
"github.com/opencontainers/runc/libcontainer/configs"
|
|
"github.com/pkg/errors"
|
|
"golang.org/x/sys/unix"
|
|
)
|
|
|
|
func isRWM(perms configs.DevicePermissions) bool {
|
|
var r, w, m bool
|
|
for _, perm := range perms {
|
|
switch perm {
|
|
case 'r':
|
|
r = true
|
|
case 'w':
|
|
w = true
|
|
case 'm':
|
|
m = true
|
|
}
|
|
}
|
|
return r && w && m
|
|
}
|
|
|
|
// the logic is from crun
|
|
// https://github.com/containers/crun/blob/0.10.2/src/libcrun/cgroup.c#L1644-L1652
|
|
func canSkipEBPFError(cgroup *configs.Cgroup) bool {
|
|
for _, dev := range cgroup.Resources.Devices {
|
|
if dev.Allow || !isRWM(dev.Permissions) {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
func setDevices(dirPath string, cgroup *configs.Cgroup) error {
|
|
// XXX: This is currently a white-list (but all callers pass a blacklist of
|
|
// devices). This is bad for a whole variety of reasons, but will need
|
|
// to be fixed with co-ordinated effort with downstreams.
|
|
devices := cgroup.Devices
|
|
insts, license, err := devicefilter.DeviceFilter(devices)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
dirFD, err := unix.Open(dirPath, unix.O_DIRECTORY|unix.O_RDONLY, 0600)
|
|
if err != nil {
|
|
return errors.Errorf("cannot get dir FD for %s", dirPath)
|
|
}
|
|
defer unix.Close(dirFD)
|
|
// XXX: This code is currently incorrect when it comes to updating an
|
|
// existing cgroup with new rules (new rulesets are just appended to
|
|
// the program list because this uses BPF_F_ALLOW_MULTI). If we didn't
|
|
// use BPF_F_ALLOW_MULTI we could actually atomically swap the
|
|
// programs.
|
|
//
|
|
// The real issue is that BPF_F_ALLOW_MULTI makes it hard to have a
|
|
// race-free blacklist because it acts as a whitelist by default, and
|
|
// having a deny-everything program cannot be overriden by other
|
|
// programs. You could temporarily insert a deny-everything program
|
|
// but that would result in spurrious failures during updates.
|
|
if _, err := ebpf.LoadAttachCgroupDeviceFilter(insts, license, dirFD); err != nil {
|
|
if !canSkipEBPFError(cgroup) {
|
|
return err
|
|
}
|
|
}
|
|
return nil
|
|
}
|