containerd/pkg/apparmor/apparmor_linux.go
Bjorn Neergaard a3265102d9
Revert "Don't check for apparmor_parser to be present"
This reverts commit 1acca8bba3.

As stated in the Godoc, this function is intended to check for presence
of `apparmor_parser`. Changing this regressed the public API of
containerd, and directly contradicts the way that this function is
consumed inside of containerd itself:
* fdfdc9bfc0/pkg/apparmor/apparmor.go (L20)
* fdfdc9bfc0/pkg/cri/sbserver/helpers_linux.go (L85)
* fdfdc9bfc0/pkg/cri/server/helpers_linux.go (L144)

This has lead to a number of painful regressions and attempted fixes in
Moby:
* https://github.com/moby/moby/issues/44900
* https://github.com/moby/moby/pull/44902
* https://github.com/moby/moby/issues/44970

While reverting this late into the life of 1.6 and at the start of the
life of 1.7 is likely painful, I think this is ultimately the best path
to take, as containerd is subject to the same failure to start
containers with an AppArmor kernel when `apparmor_parser` is missing as
Moby.

Signed-off-by: Bjorn Neergaard <bneergaard@mirantis.com>
2023-02-10 10:05:56 -07:00

46 lines
1.5 KiB
Go

/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package apparmor
import (
"os"
"sync"
)
var (
appArmorSupported bool
checkAppArmor sync.Once
)
// hostSupports returns true if apparmor is enabled for the host, if
// apparmor_parser is enabled, and if we are not running docker-in-docker.
//
// It is a modified version of libcontainer/apparmor.IsEnabled(), which does not
// check for apparmor_parser to be present, or if we're running docker-in-docker.
func hostSupports() bool {
checkAppArmor.Do(func() {
// see https://github.com/opencontainers/runc/blob/0d49470392206f40eaab3b2190a57fe7bb3df458/libcontainer/apparmor/apparmor_linux.go
if _, err := os.Stat("/sys/kernel/security/apparmor"); err == nil && os.Getenv("container") == "" {
if _, err = os.Stat("/sbin/apparmor_parser"); err == nil {
buf, err := os.ReadFile("/sys/module/apparmor/parameters/enabled")
appArmorSupported = err == nil && len(buf) > 1 && buf[0] == 'Y'
}
}
})
return appArmorSupported
}