Add secrets patch to crio

Allows the user to define secret paths in /etc/containers/mounts.conf
These are then volume mounted into the container

Signed-off-by: umohnani8 <umohnani@redhat.com>

server/secrets.go

@@ -0,0 +1,186 @@
+package server
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+
+	rspec "github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/opencontainers/selinux/go-selinux/label"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+// SecretData info
+type SecretData struct {
+	Name string
+	Data []byte
+}
+
+// SaveTo saves secret data to given directory
+func (s SecretData) SaveTo(dir string) error {
+	path := filepath.Join(dir, s.Name)
+	if err := os.MkdirAll(filepath.Dir(path), 0700); err != nil && !os.IsExist(err) {
+		return err
+	}
+	return ioutil.WriteFile(path, s.Data, 0700)
+}
+
+// readMountFile returns a list of the host:container paths
+func readMountFile(mountFilePath string) ([]string, error) {
+	var mountPaths []string
+	file, err := os.Open(mountFilePath)
+	if err != nil {
+		logrus.Warnf("file doesn't exist %q", mountFilePath)
+		return nil, nil
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	scanner.Split(bufio.ScanLines)
+	for scanner.Scan() {
+		mountPaths = append(mountPaths, scanner.Text())
+	}
+
+	return mountPaths, nil
+}
+
+func readAll(root, prefix string) ([]SecretData, error) {
+	path := filepath.Join(root, prefix)
+
+	data := []SecretData{}
+
+	files, err := ioutil.ReadDir(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return data, nil
+		}
+
+		return nil, err
+	}
+
+	for _, f := range files {
+		fileData, err := readFile(root, filepath.Join(prefix, f.Name()))
+		if err != nil {
+			// If the file did not exist, might be a dangling symlink
+			// Ignore the error
+			if os.IsNotExist(err) {
+				continue
+			}
+			return nil, err
+		}
+		data = append(data, fileData...)
+	}
+
+	return data, nil
+}
+
+func readFile(root, name string) ([]SecretData, error) {
+	path := filepath.Join(root, name)
+
+	s, err := os.Stat(path)
+	if err != nil {
+		return nil, err
+	}
+
+	if s.IsDir() {
+		dirData, err := readAll(root, name)
+		if err != nil {
+			return nil, err
+		}
+		return dirData, nil
+	}
+	bytes, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	return []SecretData{{Name: name, Data: bytes}}, nil
+}
+
+// getHostAndCtrDir separates the host:container paths
+func getMountsMap(path string) (string, string, error) {
+	arr := strings.SplitN(path, ":", 2)
+	if len(arr) == 2 {
+		return arr[0], arr[1], nil
+	}
+	return "", "", errors.Errorf("unable to get host and container dir")
+}
+
+func getHostSecretData(hostDir string) ([]SecretData, error) {
+	var allSecrets []SecretData
+	hostSecrets, err := readAll(hostDir, "")
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to read secrets from %q", hostDir)
+	}
+	return append(allSecrets, hostSecrets...), nil
+}
+
+// secretMount copies the contents of host directory to container directory
+// and returns a list of mounts
+func secretMounts(mountLabel, mountFilePath, containerWorkingDir string, runtimeMounts []rspec.Mount) ([]rspec.Mount, error) {
+	var mounts []rspec.Mount
+	mountPaths, err := readMountFile(mountFilePath)
+	if err != nil {
+		return nil, err
+	}
+	for _, path := range mountPaths {
+		hostDir, ctrDir, err := getMountsMap(path)
+		if err != nil {
+			return nil, err
+		}
+		// skip if the hostDir path doesn't exist
+		if _, err := os.Stat(hostDir); os.IsNotExist(err) {
+			logrus.Warnf("%q doesn't exist, skipping", hostDir)
+			continue
+		}
+
+		ctrDir = filepath.Join(containerWorkingDir, ctrDir)
+		// skip if ctrDir has already been mounted by caller
+		if isAlreadyMounted(runtimeMounts, ctrDir) {
+			logrus.Warnf("%q has already been mounted; cannot override mount", ctrDir)
+			continue
+		}
+
+		if err := os.RemoveAll(ctrDir); err != nil {
+			return nil, fmt.Errorf("remove container directory failed: %v", err)
+		}
+
+		if err := os.MkdirAll(ctrDir, 0755); err != nil {
+			return nil, fmt.Errorf("making container directory failed: %v", err)
+		}
+
+		hostDir, err = resolveSymbolicLink(hostDir)
+		if err != nil {
+			return nil, err
+		}
+
+		data, err := getHostSecretData(hostDir)
+		if err != nil {
+			return nil, errors.Wrapf(err, "getting host secret data failed")
+		}
+		for _, s := range data {
+			s.SaveTo(ctrDir)
+		}
+		label.Relabel(ctrDir, mountLabel, false)
+
+		m := rspec.Mount{
+			Source:      hostDir,
+			Destination: ctrDir,
+		}
+
+		mounts = append(mounts, m)
+	}
+	return mounts, nil
+}
+
+func isAlreadyMounted(mounts []rspec.Mount, mountPath string) bool {
+	for _, mount := range mounts {
+		if mount.Destination == mountPath {
+			return true
+		}
+	}
+	return false
+}