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42a1e19d67
These helpers will be needed for the compatibility code added in future patches in this series, but because "internal/pathrs" is imported by "libcontainer/utils" we need to move them so that we can avoid circular dependencies. Because the old functions were in a non-internal package it is possible some downstreams use them, so add some wrappers but mark them as deprecated. Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
69 lines
1.6 KiB
Go
69 lines
1.6 KiB
Go
package apparmor
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import (
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"errors"
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"fmt"
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"os"
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"sync"
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"golang.org/x/sys/unix"
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"github.com/opencontainers/runc/internal/pathrs"
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)
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var (
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appArmorEnabled bool
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checkAppArmor sync.Once
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)
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// isEnabled returns true if apparmor is enabled for the host.
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func isEnabled() bool {
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checkAppArmor.Do(func() {
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if _, err := os.Stat("/sys/kernel/security/apparmor"); err == nil {
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buf, err := os.ReadFile("/sys/module/apparmor/parameters/enabled")
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appArmorEnabled = err == nil && len(buf) > 1 && buf[0] == 'Y'
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}
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})
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return appArmorEnabled
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}
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func setProcAttr(attr, value string) error {
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attr = pathrs.LexicallyCleanPath(attr)
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attrSubPath := "attr/apparmor/" + attr
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if _, err := os.Stat("/proc/self/" + attrSubPath); errors.Is(err, os.ErrNotExist) {
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// fall back to the old convention
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attrSubPath = "attr/" + attr
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}
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// Under AppArmor you can only change your own attr, so there's no reason
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// to not use /proc/thread-self/ (instead of /proc/<tid>/, like libapparmor
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// does).
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f, closer, err := pathrs.ProcThreadSelfOpen(attrSubPath, unix.O_WRONLY|unix.O_CLOEXEC)
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if err != nil {
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return err
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}
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defer closer()
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defer f.Close()
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_, err = f.WriteString(value)
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return err
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}
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// changeOnExec reimplements aa_change_onexec from libapparmor in Go.
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func changeOnExec(name string) error {
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if err := setProcAttr("exec", "exec "+name); err != nil {
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return fmt.Errorf("apparmor failed to apply profile: %w", err)
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}
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return nil
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}
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// applyProfile will apply the profile with the specified name to the process
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// after the next exec.
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func applyProfile(name string) error {
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if name == "" {
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return nil
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}
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return changeOnExec(name)
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}
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