Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

skip read /proc/filesystems if process_label is null #4354

Open
wants to merge 1 commit into
base: main
Choose a base branch
from
+20 −13
Open

skip read /proc/filesystems if process_label is null #4354

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 10 additions & 7 deletions libcontainer/setns_init_linux.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -34,10 +34,12 @@ func (l *linuxSetnsInit) getSessionRingName() string {

func (l *linuxSetnsInit) Init() error {
if !l.config.Config.NoNewKeyring {
if err := selinux.SetKeyLabel(l.config.ProcessLabel); err != nil {
return err
if l.config.ProcessLabel != "" {
if err := selinux.SetKeyLabel(l.config.ProcessLabel); err != nil {
return err
}
defer selinux.SetKeyLabel("") //nolint: errcheck
}
defer selinux.SetKeyLabel("") //nolint: errcheck
Comment on lines +41 to -40
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Do we know what the intent was for these empty selinux.SetKeyLabel("") ? See my comment on opencontainers/selinux#214 (comment)

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I think it's used to clear the label for the next keyring created by the current process once we got an error when we start/exec the container. Because this label can't be inherited by sub-process, so the initial value should be "", so we can set it to an empty string directly to clear it.

Copy link
Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

can we use unix.KeyctlString() set keylabel ? @lifubang

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

can we use unix.KeyctlString() set keylabel ?

I think no.

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Do we know what the intent was for these empty selinux.SetKeyLabel("") ? See my comment on opencontainers/selinux#214 (comment)

Some are added by commit cd96170, and some are by aa3fee6, which provides an explanation:

should also call SetProcessLabel("") after the container starts
to go back to the default SELinux behaviour.

Given the fact that Init() never returns unless there's an error (because it ends with exec), those defers are only called in case of an error.

// Do not inherit the parent's session keyring.
if _, err := keys.JoinSessionKeyring(l.getSessionRingName()); err != nil {
// Same justification as in standart_init_linux.go as to why we
Expand Down Expand Up @@ -84,11 +86,12 @@ func (l *linuxSetnsInit) Init() error {
if err := syncParentReady(l.pipe); err != nil {
return fmt.Errorf("sync ready: %w", err)
}

if err := selinux.SetExecLabel(l.config.ProcessLabel); err != nil {
return err
if l.config.ProcessLabel != "" {
if err := selinux.SetExecLabel(l.config.ProcessLabel); err != nil {
return err
}
defer selinux.SetExecLabel("") //nolint: errcheck
}
defer selinux.SetExecLabel("") //nolint: errcheck
// Without NoNewPrivileges seccomp is a privileged operation, so we need to
// do this before dropping capabilities; otherwise do it as late as possible
// just before execve so as few syscalls take place after it as possible.
Expand Down
16 changes: 10 additions & 6 deletions libcontainer/standard_init_linux.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -48,10 +48,12 @@ func (l *linuxStandardInit) getSessionRingParams() (string, uint32, uint32) {

func (l *linuxStandardInit) Init() error {
if !l.config.Config.NoNewKeyring {
if err := selinux.SetKeyLabel(l.config.ProcessLabel); err != nil {
return err
if l.config.ProcessLabel != "" {
if err := selinux.SetKeyLabel(l.config.ProcessLabel); err != nil {
return err
}
defer selinux.SetKeyLabel("") //nolint: errcheck
}
defer selinux.SetKeyLabel("") //nolint: errcheck
ringname, keepperms, newperms := l.getSessionRingParams()

// Do not inherit the parent's session keyring.
Expand Down Expand Up @@ -173,10 +175,12 @@ func (l *linuxStandardInit) Init() error {
if err := syncParentReady(l.pipe); err != nil {
return fmt.Errorf("sync ready: %w", err)
}
if err := selinux.SetExecLabel(l.config.ProcessLabel); err != nil {
return fmt.Errorf("can't set process label: %w", err)
if l.config.ProcessLabel != "" {
if err := selinux.SetExecLabel(l.config.ProcessLabel); err != nil {
return fmt.Errorf("can't set process label: %w", err)
}
defer selinux.SetExecLabel("") //nolint: errcheck
}
defer selinux.SetExecLabel("") //nolint: errcheck
// Without NoNewPrivileges seccomp is a privileged operation, so we need to
// do this before dropping capabilities; otherwise do it as late as possible
// just before execve so as few syscalls take place after it as possible.
Expand Down
Loading