From 80072183953f8cf6fcef6b5e65e609e833dd9fb8 Mon Sep 17 00:00:00 2001 From: Aleksa Sarai Date: Wed, 8 Mar 2017 11:43:29 +1100 Subject: [PATCH 2/2] SUSE: implement SUSE container secrets This allows for us to pass in host credentials to a container, allowing for SUSEConnect to work with containers. THIS PATCH IS NOT TO BE UPSTREAMED, DUE TO THE FACT THAT IT IS SUSE-SPECIFIC, AND UPSTREAM DOES NOT APPROVE OF THIS CONCEPT BECAUSE IT MAKES BUILDS NOT ENTIRELY REPRODUCIBLE. SUSE-Bugs: bsc#1057743 bsc#1055676 bsc#1030702 Signed-off-by: Aleksa Sarai --- components/engine/daemon/start.go | 5 + components/engine/daemon/suse_secrets.go | 396 +++++++++++++++++++++++ 2 files changed, 401 insertions(+) create mode 100644 components/engine/daemon/suse_secrets.go diff --git a/components/engine/daemon/start.go b/components/engine/daemon/start.go index 57a7267b7cbb..46c3a603554f 100644 --- a/components/engine/daemon/start.go +++ b/components/engine/daemon/start.go @@ -151,6 +151,11 @@ func (daemon *Daemon) containerStart(container *container.Container, checkpoint return err } + // SUSE:secrets -- inject the SUSE secret store + if err := daemon.injectSuseSecretStore(container); err != nil { + return errdefs.System(err) + } + spec, err := daemon.createSpec(container) if err != nil { return errdefs.System(err) diff --git a/components/engine/daemon/suse_secrets.go b/components/engine/daemon/suse_secrets.go new file mode 100644 index 000000000000..087c877015a7 --- /dev/null +++ b/components/engine/daemon/suse_secrets.go @@ -0,0 +1,396 @@ +/* + * suse-secrets: patch for Docker to implement SUSE secrets + * Copyright (C) 2017 SUSE LLC. + * + * 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 daemon + +import ( + "archive/tar" + "bytes" + "fmt" + "io" + "io/ioutil" + "os" + "path/filepath" + "strings" + "syscall" + + "github.com/docker/docker/container" + "github.com/docker/docker/pkg/archive" + "github.com/docker/docker/pkg/idtools" + "github.com/opencontainers/go-digest" + "github.com/sirupsen/logrus" + + swarmtypes "github.com/docker/docker/api/types/swarm" + swarmexec "github.com/docker/swarmkit/agent/exec" + swarmapi "github.com/docker/swarmkit/api" +) + +func init() { + // Output to tell us in logs that SUSE:secrets is enabled. + logrus.Infof("SUSE:secrets :: enabled") +} + +// Creating a fake file. +type SuseFakeFile struct { + Path string + Uid int + Gid int + Mode os.FileMode + Data []byte +} + +func (s SuseFakeFile) id() string { + // NOTE: It is _very_ important that this string always has a prefix of + // "suse". This is how we can ensure that we can operate on + // SecretReferences with a confidence that it was made by us. + return fmt.Sprintf("suse_%s_%s", digest.FromBytes(s.Data).Hex(), s.Path) +} + +func (s SuseFakeFile) toSecret() *swarmapi.Secret { + return &swarmapi.Secret{ + ID: s.id(), + Internal: true, + Spec: swarmapi.SecretSpec{ + Data: s.Data, + }, + } +} + +func (s SuseFakeFile) toSecretReference(idMaps *idtools.IdentityMapping) *swarmtypes.SecretReference { + // Figure out the host-facing {uid,gid} based on the provided maps. Fall + // back to root if the UID/GID don't match (we are guaranteed that root is + // mapped). + ctrUser := idtools.Identity{UID: s.Uid, GID: s.Gid} + hostUser := idMaps.RootPair() + if user, err := idMaps.ToHost(ctrUser); err == nil { + hostUser = user + } + + // Return the secret reference as a file target. + return &swarmtypes.SecretReference{ + SecretID: s.id(), + SecretName: s.id(), + File: &swarmtypes.SecretReferenceFileTarget{ + Name: s.Path, + UID: fmt.Sprintf("%d", hostUser.UID), + GID: fmt.Sprintf("%d", hostUser.GID), + Mode: s.Mode, + }, + } +} + +// readDir will recurse into a directory prefix/dir, and return the set of +// secrets in that directory (as a tar archive that is packed inside the "data" +// field). The Path attribute of each has the prefix stripped. Symlinks are +// dereferenced. +func readDir(prefix, dir string) ([]*SuseFakeFile, error) { + var suseFiles []*SuseFakeFile + + path := filepath.Join(prefix, dir) + fi, err := os.Stat(path) + if err != nil { + // Ignore dangling symlinks. + if os.IsNotExist(err) { + logrus.Warnf("SUSE:secrets :: dangling symlink: %s", path) + return nil, nil + } + return nil, err + } else if !fi.IsDir() { + // Just to be safe. + logrus.Warnf("SUSE:secrets :: expected %q to be a directory, but was a file", path) + return readFile(prefix, dir) + } + path, err = filepath.EvalSymlinks(path) + if err != nil { + return nil, err + } + + // Construct a tar archive of the source directory. We tar up the prefix + // directory and add dir as an IncludeFiles specifically so that we + // preserve the name of the directory itself. + tarStream, err := archive.TarWithOptions(path, &archive.TarOptions{ + Compression: archive.Uncompressed, + IncludeSourceDir: true, + }) + if err != nil { + return nil, fmt.Errorf("SUSE:secrets :: failed to tar source directory %q: %v", path, err) + } + tarStreamBytes, err := ioutil.ReadAll(tarStream) + if err != nil { + return nil, fmt.Errorf("SUSE:secrets :: failed to read full tar archive: %v", err) + } + + // Get a list of the symlinks in the tar archive. + var symlinks []string + tmpTr := tar.NewReader(bytes.NewBuffer(tarStreamBytes)) + for { + hdr, err := tmpTr.Next() + if err == io.EOF { + break + } + if err != nil { + return nil, fmt.Errorf("SUSE:secrets :: failed to read through tar reader: %v", err) + } + if hdr.Typeflag == tar.TypeSymlink { + symlinks = append(symlinks, hdr.Name) + } + } + + // Symlinks aren't dereferenced in the above archive, so we explicitly do a + // rewrite of the tar archive to include all symlinks to files. We cannot + // do directories here, but lower-level directory symlinks aren't supported + // by zypper so this isn't an issue. + symlinkModifyMap := map[string]archive.TarModifierFunc{} + for _, sym := range symlinks { + logrus.Debugf("SUSE:secrets: archive(%q) %q is a need-to-rewrite symlink", path, sym) + symlinkModifyMap[sym] = func(tarPath string, hdr *tar.Header, r io.Reader) (*tar.Header, []byte, error) { + logrus.Debugf("SUSE:secrets: archive(%q) mapping for symlink %q", path, tarPath) + tarFullPath := filepath.Join(path, tarPath) + + // Get a copy of the original byte stream. + oldContent, err := ioutil.ReadAll(r) + if err != nil { + return nil, nil, fmt.Errorf("suse_rewrite: failed to read archive entry %q: %v", tarPath, err) + } + + // Check that the file actually exists. + fi, err := os.Stat(tarFullPath) + if err != nil { + logrus.Warnf("suse_rewrite: failed to stat archive entry %q: %v", tarFullPath, err) + return hdr, oldContent, nil + } + + // Read the actual contents. + content, err := ioutil.ReadFile(tarFullPath) + if err != nil { + logrus.Warnf("suse_rewrite: failed to read %q: %v", tarFullPath, err) + return hdr, oldContent, nil + } + + newHdr, err := tar.FileInfoHeader(fi, "") + if err != nil { + // Fake the header. + newHdr = &tar.Header{ + Typeflag: tar.TypeReg, + Mode: 0644, + } + } + + // Update the key fields. + hdr.Typeflag = newHdr.Typeflag + hdr.Mode = newHdr.Mode + hdr.Linkname = "" + return hdr, content, nil + } + } + + // Create the rewritten tar stream. + tarStream = archive.ReplaceFileTarWrapper(ioutil.NopCloser(bytes.NewBuffer(tarStreamBytes)), symlinkModifyMap) + tarStreamBytes, err = ioutil.ReadAll(tarStream) + if err != nil { + return nil, fmt.Errorf("SUSE:secrets :: failed to read rewritten archive: %v", err) + } + + // Add the tar stream as a "file". + suseFiles = append(suseFiles, &SuseFakeFile{ + Path: dir, + Mode: fi.Mode(), + Data: tarStreamBytes, + }) + return suseFiles, nil +} + +// readFile returns a secret given a file under a given prefix. +func readFile(prefix, file string) ([]*SuseFakeFile, error) { + path := filepath.Join(prefix, file) + fi, err := os.Stat(path) + if err != nil { + // Ignore dangling symlinks. + if os.IsNotExist(err) { + logrus.Warnf("SUSE:secrets :: dangling symlink: %s", path) + return nil, nil + } + return nil, err + } else if fi.IsDir() { + // Just to be safe. + logrus.Warnf("SUSE:secrets :: expected %q to be a file, but was a directory", path) + return readDir(prefix, file) + } + + stat, ok := fi.Sys().(*syscall.Stat_t) + if !ok { + logrus.Warnf("SUSE:secrets :: failed to cast file stat_t: defaulting to owned by root:root: %s", path) + } + + bytes, err := ioutil.ReadFile(path) + if err != nil { + return nil, err + } + + var suseFiles []*SuseFakeFile + suseFiles = append(suseFiles, &SuseFakeFile{ + Path: file, + Uid: int(stat.Uid), + Gid: int(stat.Gid), + Mode: fi.Mode(), + Data: bytes, + }) + return suseFiles, nil +} + +// getHostSuseSecretData returns the list of SuseFakeFiles the need to be added +// as SUSE secrets. +func getHostSuseSecretData() ([]*SuseFakeFile, error) { + secrets := []*SuseFakeFile{} + + credentials, err := readDir("/etc/zypp", "credentials.d") + if err != nil { + if os.IsNotExist(err) { + credentials = []*SuseFakeFile{} + } else { + logrus.Errorf("SUSE:secrets :: error while reading zypp credentials: %s", err) + return nil, err + } + } + secrets = append(secrets, credentials...) + + suseConnect, err := readFile("/etc", "SUSEConnect") + if err != nil { + if os.IsNotExist(err) { + suseConnect = []*SuseFakeFile{} + } else { + logrus.Errorf("SUSE:secrets :: error while reading /etc/SUSEConnect: %s", err) + return nil, err + } + } + secrets = append(secrets, suseConnect...) + + return secrets, nil +} + +// To fake an empty store, in the case where we are operating on a container +// that was created pre-swarmkit. Otherwise segfaults and other fun things +// happen. See bsc#1057743. +type ( + suseEmptyStore struct{} + suseEmptySecret struct{} + suseEmptyConfig struct{} +) + +// In order to reduce the amount of code touched outside of this file, we +// implement the swarm API for DependencyGetter. This asserts that this +// requirement will always be matched. In addition, for the case of the *empty* +// getters this reduces memory usage by having a global instance. +var ( + _ swarmexec.DependencyGetter = &suseDependencyStore{} + emptyStore swarmexec.DependencyGetter = suseEmptyStore{} + emptySecret swarmexec.SecretGetter = suseEmptySecret{} + emptyConfig swarmexec.ConfigGetter = suseEmptyConfig{} +) + +var errSuseEmptyStore = fmt.Errorf("SUSE:secrets :: tried to get a resource from empty store [this is a bug]") + +func (_ suseEmptyConfig) Get(_ string) (*swarmapi.Config, error) { return nil, errSuseEmptyStore } +func (_ suseEmptySecret) Get(_ string) (*swarmapi.Secret, error) { return nil, errSuseEmptyStore } +func (_ suseEmptyStore) Secrets() swarmexec.SecretGetter { return emptySecret } +func (_ suseEmptyStore) Configs() swarmexec.ConfigGetter { return emptyConfig } + +type suseDependencyStore struct { + dfl swarmexec.DependencyGetter + secrets map[string]*swarmapi.Secret +} + +// The following are effectively dumb wrappers that return ourselves, or the +// default. +func (s *suseDependencyStore) Secrets() swarmexec.SecretGetter { return s } +func (s *suseDependencyStore) Configs() swarmexec.ConfigGetter { return s.dfl.Configs() } + +// Get overrides the underlying DependencyGetter with our own secrets (falling +// through to the underlying DependencyGetter if the secret isn't present). +func (s *suseDependencyStore) Get(id string) (*swarmapi.Secret, error) { + logrus.Debugf("SUSE:secrets :: id=%s requested from suseDependencyGetter", id) + + secret, ok := s.secrets[id] + if !ok { + // fallthrough + return s.dfl.Secrets().Get(id) + } + return secret, nil +} + +// removeSuseSecrets removes any SecretReferences which were added by us +// explicitly (this is detected by checking that the prefix has a 'suse' +// prefix). See bsc#1057743. +func removeSuseSecrets(c *container.Container) { + var without []*swarmtypes.SecretReference + for _, secret := range c.SecretReferences { + if strings.HasPrefix(secret.SecretID, "suse") { + logrus.Warnf("SUSE:secrets :: removing 'old' suse secret %q from container %q", secret.SecretID, c.ID) + continue + } + without = append(without, secret) + } + c.SecretReferences = without +} + +func (daemon *Daemon) injectSuseSecretStore(c *container.Container) error { + newDependencyStore := &suseDependencyStore{ + dfl: c.DependencyStore, + secrets: make(map[string]*swarmapi.Secret), + } + // Handle old containers. See bsc#1057743. + if newDependencyStore.dfl == nil { + newDependencyStore.dfl = emptyStore + } + + // We drop any "old" SUSE secrets, as it appears that old containers (when + // restarted) could still have references to old secrets. The .id() of all + // secrets have a prefix of "suse" so this is much easier. See bsc#1057743 + // for details on why this could cause issues. + removeSuseSecrets(c) + + secrets, err := getHostSuseSecretData() + if err != nil { + return err + } + + idMaps := daemon.idMapping + for _, secret := range secrets { + newDependencyStore.secrets[secret.id()] = secret.toSecret() + c.SecretReferences = append(c.SecretReferences, secret.toSecretReference(idMaps)) + } + + c.DependencyStore = newDependencyStore + + // bsc#1057743 -- In older versions of Docker we added volumes explicitly + // to the mount list. This causes clashes because of duplicate namespaces. + // If we see an existing mount that will clash with the in-built secrets + // mount we assume it's our fault. + intendedMounts, err := c.SecretMounts() + if err != nil { + logrus.Warnf("SUSE:secrets :: fetching old secret mounts: %v", err) + return err + } + for _, intendedMount := range intendedMounts { + mountPath := intendedMount.Destination + if volume, ok := c.MountPoints[mountPath]; ok { + logrus.Debugf("SUSE:secrets :: removing pre-existing %q mount: %#v", mountPath, volume) + delete(c.MountPoints, mountPath) + } + } + return nil +} -- 2.22.0