Give access to the CA certificates from the host

This uses the same approach taken by Flatpak [1] to ensure that the
certificates from certificate authorities (or CAs) that are available
inside a Toolbx container are kept synchronized with the host operating
system.  Any program that uses PKCS #11 to access CA certificates should
see the same ones both inside the container and on the host.

During every 'enter' and 'run' command, toolbox(1) ensures that an
instance of 'p11-kit server' is running on the host listening on a local
file system socket that's accessible to both the container and the host.
If an instance is already running, then a second one is not created.
The location of the socket is injected into the container through the
P11_KIT_SERVER_ADDRESS environment variable.

Just like Flatpak, the singleton 'p11-kit server' process is not
terminated when the last 'enter' or 'run' command exits.

The Toolbx container's entry point configures it to use the
p11-kit-client.so PKCS #11 module instead of the usual p11-kit-trust.so
module.  This talks to the 'p11-kit server' instance running on the host
over the socket instead of reading the CA certificates that are present
inside the container.

However, unlike Flatpak, this doesn't use D-Bus to set up the
communication between the container and the host, because when invoked
as 'sudo toolbox ...' there's no user or session D-Bus instance
available for the root user.

This set-up is skipped if 'p11-kit server' can't be run on the host, or
if the /etc/pkcs11/modules directory for configuring PKCS #11 modules or
p11-kit-client.so are missing inside the container.  None of these are
considered hard dependencies to accommodate size-constrained OSes like
Fedora CoreOS that might not have 'p11-kit server', and existing Toolbx
containers and old images that might not have p11-kit-client.so.

The UBI-based toolbox images haven't yet been updated to contain
p11-kit-client.so.  Until that happens, containers created from them
won't have access to the CA certificates from the host.

The CI needs to be run without 'p11-kit server' because the lingering
singleton process causes Bats to hang when tearing down the suite of
system tests [2].  To terminate the 'p11-kit server' instance run by the
system tests, it needs to be distinguishable from the instance run by
'normal' use of Toolbx by the user.  One way to do this is to isolate
the host operating system's XDG_RUNTIME_DIR from the system tests.
Unfortunately, this is easier said than done [3].  So, this workaround
has to suffice until the problem is solved.

On the Ubuntu 22.04 CI nodes, it's not possible to remove the p11-kit
package that provides 'p11-kit server', because it leads to:
  $ sudo dpkg --purge p11-kit
  dpkg: dependency problems prevent removal of p11-kit:
   adoptium-ca-certificates depends on p11-kit.

Therefore, as a workaround only the /usr/libexec/p11-kit/p11-kit-server
binary that provides the 'server' command is removed.  The rest of the
p11-kit package is left untouched.

[1] Flatpak commit 66b2ff40f7caf3a7
    https://github.com/flatpak/flatpak/commit/66b2ff40f7caf3a7
    https://github.com/flatpak/flatpak/pull/1757
    https://github.com/p11-glue/p11-kit/issues/68

[2] https://bats-core.readthedocs.io/en/stable/writing-tests.html

[3] https://github.com/containers/toolbox/pull/1652

https://github.com/containers/toolbox/issues/626

.github/workflows/ubuntu-tests.yaml

@@ -1,5 +1,5 @@
 #
-# Copyright © 2023 – 2024 Red Hat, Inc.
+# Copyright © 2023 – 2025 Red Hat, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -55,6 +55,9 @@ jobs:
             systemd \
             udisks2
 
+      - name: Ensure that 'p11-kit server' is absent
+        run: sudo rm /usr/libexec/p11-kit/p11-kit-server
+
       - name: Set up PATH for Go 1.21
         run: |
           echo "PATH=/usr/lib/go-1.21/bin:$PATH" >> "$GITHUB_ENV"
@@ -131,7 +134,7 @@ jobs:
         working-directory: containers/toolbox/src
 
       - name: Set up build directory
-        run: meson setup --fatal-meson-warnings builddir
+        run: meson setup builddir
         working-directory: containers/toolbox
 
       - name: Build

meson.build

@@ -23,6 +23,27 @@ bats = find_program('bats', required: false)
 codespell = find_program('codespell', required: false)
 htpasswd = find_program('htpasswd', required: false)
 openssl = find_program('openssl', required: false)
+
+p11kit_server_works = false
+p11kit = find_program('p11-kit', required: false)
+if p11kit.found()
+  res = run_command(p11kit, 'server', check: false)
+  if res.returncode() == 0
+    error('Command \'p11-kit server\' was supposed to fail')
+  endif
+
+  res_stdout = res.stdout()
+  if res_stdout.contains('--name') and res_stdout.contains('--provider')
+    p11kit_server_works = true
+  else
+    warning('Command \'p11-kit server\' doesn\'t work')
+  endif
+endif
+
+if not p11kit_server_works
+  warning('Containers won\'t have access to the CA certificates from the host')
+endif
+
 podman = find_program('podman', required: false)
 shellcheck = find_program('shellcheck', required: false)
 skopeo = find_program('skopeo', required: false)

playbooks/dependencies-centos-9-stream.yaml

@@ -38,6 +38,13 @@
       - codespell
       - fish
 
+- name: Ensure that 'p11-kit server' is absent
+  become: yes
+  package:
+    name:
+      - p11-kit-server
+    state: absent
+
 - name: Download Go modules
   command: go mod download -x
   environment:

playbooks/dependencies-fedora-restricted.yaml

@@ -1,5 +1,5 @@
 #
-# Copyright © 2023 – 2024 Red Hat, Inc.
+# Copyright © 2023 – 2025 Red Hat, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -47,6 +47,15 @@
     update_cache: "{{ true if zuul.attempts > 1 else false }}"
     use: "{{ 'dnf' if zuul.attempts > 1 else 'auto' }}"
 
+- name: Ensure that 'p11-kit server' is absent
+  become: yes
+  package:
+    name:
+      - p11-kit-server
+    state: absent
+    update_cache: "{{ true if zuul.attempts > 1 else false }}"
+    use: "{{ 'dnf' if zuul.attempts > 1 else 'auto' }}"
+
 - name: Ensure that podman(1) is absent
   become: yes
   package:

playbooks/dependencies-fedora.yaml

@@ -1,5 +1,5 @@
 #
-# Copyright © 2022 – 2024 Red Hat, Inc.
+# Copyright © 2022 – 2025 Red Hat, Inc.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -39,6 +39,15 @@
       - udisks2
     use: "{{ 'dnf' if zuul.attempts > 1 else 'auto' }}"
 
+- name: Ensure that 'p11-kit server' is absent
+  become: yes
+  package:
+    name:
+      - p11-kit-server
+    state: absent
+    update_cache: "{{ true if zuul.attempts > 1 else false }}"
+    use: "{{ 'dnf' if zuul.attempts > 1 else 'auto' }}"
+
 - name: Download Go modules
   command: go mod download -x
   environment:

playbooks/setup-env-migration-path-for-coreos-toolbox.yaml

@@ -20,6 +20,6 @@
     - include_tasks: dependencies-centos-9-stream.yaml
 
     - name: Set up build directory
-      command: meson -Dmigration_path_for_coreos_toolbox=true --fatal-meson-warnings builddir
+      command: meson -Dmigration_path_for_coreos_toolbox=true builddir
       args:
         chdir: '{{ zuul.project.src_dir }}'

playbooks/setup-env-restricted.yaml

@@ -20,6 +20,6 @@
     - include_tasks: dependencies-fedora-restricted.yaml
 
     - name: Set up build directory
-      command: meson setup --fatal-meson-warnings builddir
+      command: meson setup builddir
       args:
         chdir: '{{ zuul.project.src_dir }}'

playbooks/setup-env.yaml

@@ -20,6 +20,6 @@
     - include_tasks: dependencies-fedora.yaml
 
     - name: Set up build directory
-      command: meson setup --fatal-meson-warnings builddir
+      command: meson setup builddir
       args:
         chdir: '{{ zuul.project.src_dir }}'

src/cmd/initContainer.go

@@ -301,6 +301,10 @@ func initContainer(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	if err := configurePKCS11(targetUser); err != nil {
+		return err
+	}
+
 	if err := configureRPM(); err != nil {
 		return err
 	}
@@ -569,6 +573,57 @@ func configureKerberos() error {
 	return nil
 }
 
+func configurePKCS11(targetUser *user.User) error {
+	const logPrefix = "Configuring PKCS #11 to read from the host"
+	logrus.Debugf("%s", logPrefix)
+
+	if path := "/etc/pkcs11/modules"; !utils.PathExists(path) {
+		logrus.Debugf("%s: directory %s not found", logPrefix, path)
+		logrus.Debugf("%s: skipping", logPrefix)
+		return nil
+	}
+
+	if ok, err := utils.IsP11KitClientPresent(); err != nil {
+		logrus.Debugf("%s: %s", logPrefix, err)
+
+		if !ok {
+			logrus.Debugf("%s: p11-kit-client.so not found", logPrefix)
+			logrus.Debugf("%s: skipping", logPrefix)
+			return nil
+		}
+	} else {
+		if !ok {
+			logrus.Debugf("%s: p11-kit-client.so not found", logPrefix)
+			logrus.Debugf("%s: skipping", logPrefix)
+			return nil
+		}
+	}
+
+	if path, err := utils.GetP11KitServerSocket(targetUser); err != nil {
+		return err
+	} else if !utils.PathExists(path) {
+		logrus.Debugf("%s: socket %s not found", logPrefix, path)
+		logrus.Debugf("%s: skipping", logPrefix)
+		return nil
+	}
+
+	var builder strings.Builder
+	builder.WriteString("# Written by Toolbx\n")
+	builder.WriteString("# https://containertoolbx.org/\n")
+	builder.WriteString("\n")
+	builder.WriteString("module: p11-kit-client.so\n")
+
+	pkcs11ConfigString := builder.String()
+	pkcs11ConfigBytes := []byte(pkcs11ConfigString)
+	if err := renameio.WriteFile("/etc/pkcs11/modules/p11-kit-trust.module",
+		pkcs11ConfigBytes,
+		0644); err != nil {
+		return fmt.Errorf("failed to configure PKCS #11 to read from the host: %w", err)
+	}
+
+	return nil
+}
+
 func configureRPM() error {
 	if !utils.PathExists("/usr/lib/rpm/macros.d") {
 		return nil

src/cmd/run.go

@@ -27,6 +27,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"syscall"
 	"time"
 
 	"github.com/containers/toolbox/pkg/nvidia"
@@ -283,6 +284,11 @@ func runCommand(container string,
 		cdiEnviron = append(cdiEnviron, cdiSpecForNvidia.ContainerEdits.Env...)
 	}
 
+	p11KitServerEnviron, err := startP11KitServer()
+	if err != nil {
+		return err
+	}
+
 	startContainerTimestamp := time.Unix(-1, 0)
 
 	if entryPointPID <= 0 {
@@ -335,10 +341,11 @@ func runCommand(container string,
 
 	logrus.Debugf("Container %s is initialized", container)
 
+	environ := append(cdiEnviron, p11KitServerEnviron...)
 	if err := runCommandWithFallbacks(container,
 		preserveFDs,
 		command,
-		cdiEnviron,
+		environ,
 		emitEscapeSequence,
 		fallbackToBash); err != nil {
 		return err
@@ -1033,6 +1040,68 @@ func startContainer(container string) error {
 	return nil
 }
 
+func startP11KitServer() ([]string, error) {
+	serverSocket, err := utils.GetP11KitServerSocket(currentUser)
+	if err != nil {
+		return nil, err
+	}
+
+	const logPrefix = "Starting 'p11-kit server'"
+	logrus.Debugf("%s with socket %s", logPrefix, serverSocket)
+
+	serverSocketLock, err := utils.GetP11KitServerSocketLock(currentUser)
+	if err != nil {
+		return nil, err
+	}
+
+	serverSocketLockFile, err := utils.Flock(serverSocketLock, syscall.LOCK_EX)
+	if err != nil {
+		logrus.Debugf("%s: %s", logPrefix, err)
+
+		var errFlock *utils.FlockError
+
+		if errors.As(err, &errFlock) {
+			if errors.Is(err, utils.ErrFlockAcquire) {
+				err = utils.ErrFlockAcquire
+			} else if errors.Is(err, utils.ErrFlockCreate) {
+				err = utils.ErrFlockCreate
+			} else {
+				panicMsg := fmt.Sprintf("unexpected %T: %s", err, err)
+				panic(panicMsg)
+			}
+		}
+
+		return nil, err
+	}
+
+	defer serverSocketLockFile.Close()
+
+	serverSocketAddress := fmt.Sprintf("P11_KIT_SERVER_ADDRESS=unix:path=%s", serverSocket)
+	serverEnviron := []string{
+		serverSocketAddress,
+	}
+
+	if utils.PathExists(serverSocket) {
+		logrus.Debugf("%s: socket %s already exists", logPrefix, serverSocket)
+		logrus.Debugf("%s: skipping", logPrefix)
+		return serverEnviron, nil
+	}
+
+	serverArgs := []string{
+		"server",
+		"--name", serverSocket,
+		"--provider", "p11-kit-trust.so",
+		"pkcs11:model=p11-kit-trust?write-protected=yes",
+	}
+
+	if err := shell.Run("p11-kit", nil, nil, nil, serverArgs...); err != nil {
+		logrus.Debugf("%s failed: %s", logPrefix, err)
+		return nil, nil
+	}
+
+	return serverEnviron, nil
+}
+
 func (err *entryPointError) Error() string {
 	return err.msg
 }

src/pkg/utils/utils.go

@@ -503,6 +503,26 @@ func GetMountOptions(target string) (string, error) {
 	return mountOptions, nil
 }
 
+func GetP11KitServerSocket(targetUser *user.User) (string, error) {
+	toolbxRuntimeDirectory, err := GetRuntimeDirectory(targetUser)
+	if err != nil {
+		return "", err
+	}
+
+	p11KitServerSocket := filepath.Join(toolbxRuntimeDirectory, "pkcs11")
+	return p11KitServerSocket, nil
+}
+
+func GetP11KitServerSocketLock(targetUser *user.User) (string, error) {
+	toolbxRuntimeDirectory, err := GetRuntimeDirectory(targetUser)
+	if err != nil {
+		return "", err
+	}
+
+	p11KitServerSocketLock := filepath.Join(toolbxRuntimeDirectory, "pkcs11.lock")
+	return p11KitServerSocketLock, nil
+}
+
 func GetRuntimeDirectory(targetUser *user.User) (string, error) {
 	if runtimeDirectories == nil {
 		runtimeDirectories = make(map[string]string)