summaryrefslogtreecommitdiff
path: root/pkg/secrets/secrets.go
blob: 242953609ff14843342ab9aaa6fbd4c2326292af (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
package secrets

import (
	"bufio"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"

	"github.com/containers/libpod/pkg/rootless"
	rspec "github.com/opencontainers/runtime-spec/specs-go"
	"github.com/opencontainers/selinux/go-selinux/label"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
)

var (
	// DefaultMountsFile holds the default mount paths in the form
	// "host_path:container_path"
	DefaultMountsFile = "/usr/share/containers/mounts.conf"
	// OverrideMountsFile holds the default mount paths in the form
	// "host_path:container_path" overridden by the user
	OverrideMountsFile = "/etc/containers/mounts.conf"
	// UserOverrideMountsFile holds the default mount paths in the form
	// "host_path:container_path" overridden by the rootless user
	UserOverrideMountsFile = filepath.Join(os.Getenv("HOME"), ".config/containers/mounts.conf")
)

// secretData stores the name of the file and the content read from it
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)
}

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
}

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
}

func getMounts(filePath string) []string {
	file, err := os.Open(filePath)
	if err != nil {
		// This is expected on most systems
		logrus.Debugf("file %q not found, skipping...", filePath)
		return nil
	}
	defer file.Close()
	scanner := bufio.NewScanner(file)
	if err = scanner.Err(); err != nil {
		logrus.Errorf("error reading file %q, %v skipping...", filePath, err)
		return nil
	}
	var mounts []string
	for scanner.Scan() {
		mounts = append(mounts, scanner.Text())
	}
	return mounts
}

// 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")
}

// SecretMounts copies, adds, and mounts the secrets to the container root filesystem
func SecretMounts(mountLabel, containerWorkingDir, mountFile string) []rspec.Mount {
	return SecretMountsWithUIDGID(mountLabel, containerWorkingDir, mountFile, containerWorkingDir, 0, 0)
}

// SecretMountsWithUIDGID specifies the uid/gid of the owner
func SecretMountsWithUIDGID(mountLabel, containerWorkingDir, mountFile, mountPrefix string, uid, gid int) []rspec.Mount {
	var (
		secretMounts []rspec.Mount
		mountFiles   []string
	)
	// Add secrets from paths given in the mounts.conf files
	// mountFile will have a value if the hidden --default-mounts-file flag is set
	// Note for testing purposes only
	if mountFile == "" {
		mountFiles = append(mountFiles, []string{OverrideMountsFile, DefaultMountsFile}...)
		if rootless.IsRootless() {
			mountFiles = append([]string{UserOverrideMountsFile}, mountFiles...)
			_, err := os.Stat(UserOverrideMountsFile)
			if err != nil && os.IsNotExist(err) {
				os.MkdirAll(filepath.Dir(UserOverrideMountsFile), 0755)
				if f, err := os.Create(UserOverrideMountsFile); err != nil {
					logrus.Warnf("could not create file %s: %v", UserOverrideMountsFile, err)
				} else {
					f.Close()
				}
			}
		}
	} else {
		mountFiles = append(mountFiles, mountFile)
	}
	for _, file := range mountFiles {
		if _, err := os.Stat(file); err == nil {
			mounts, err := addSecretsFromMountsFile(file, mountLabel, containerWorkingDir, mountPrefix, uid, gid)
			if err != nil {
				logrus.Warnf("error mounting secrets, skipping: %v", err)
			}
			secretMounts = mounts
			break
		}
	}

	// Add FIPS mode secret if /etc/system-fips exists on the host
	_, err := os.Stat("/etc/system-fips")
	if err == nil {
		if err := addFIPSModeSecret(&secretMounts, containerWorkingDir); err != nil {
			logrus.Errorf("error adding FIPS mode secret to container: %v", err)
		}
	} else if os.IsNotExist(err) {
		logrus.Debug("/etc/system-fips does not exist on host, not mounting FIPS mode secret")
	} else {
		logrus.Errorf("stat /etc/system-fips failed for FIPS mode secret: %v", err)
	}
	return secretMounts
}

func rchown(chowndir string, uid, gid int) error {
	return filepath.Walk(chowndir, func(filePath string, f os.FileInfo, err error) error {
		return os.Lchown(filePath, uid, gid)
	})
}

// addSecretsFromMountsFile copies the contents of host directory to container directory
// and returns a list of mounts
func addSecretsFromMountsFile(filePath, mountLabel, containerWorkingDir, mountPrefix string, uid, gid int) ([]rspec.Mount, error) {
	var mounts []rspec.Mount
	defaultMountsPaths := getMounts(filePath)
	for _, path := range defaultMountsPaths {
		hostDir, ctrDir, err := getMountsMap(path)
		if err != nil {
			return nil, err
		}
		// skip if the hostDir path doesn't exist
		if _, err = os.Stat(hostDir); err != nil {
			if os.IsNotExist(err) {
				logrus.Warnf("Path %q from %q doesn't exist, skipping", hostDir, filePath)
				continue
			}
			return nil, errors.Wrapf(err, "failed to stat %q", hostDir)
		}

		ctrDirOnHost := filepath.Join(containerWorkingDir, ctrDir)

		// In the event of a restart, don't want to copy secrets over again as they already would exist in ctrDirOnHost
		_, err = os.Stat(ctrDirOnHost)
		if os.IsNotExist(err) {
			if err = os.MkdirAll(ctrDirOnHost, 0755); err != nil {
				return nil, errors.Wrapf(err, "making container directory %q failed", ctrDirOnHost)
			}
			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 {
				if err := s.saveTo(ctrDirOnHost); err != nil {
					return nil, errors.Wrapf(err, "error saving data to container filesystem on host %q", ctrDirOnHost)
				}
			}

			err = label.Relabel(ctrDirOnHost, mountLabel, false)
			if err != nil {
				return nil, errors.Wrap(err, "error applying correct labels")
			}
			if uid != 0 || gid != 0 {
				if err := rchown(ctrDirOnHost, uid, gid); err != nil {
					return nil, err
				}
			}
		} else if err != nil {
			return nil, errors.Wrapf(err, "error getting status of %q", ctrDirOnHost)
		}

		m := rspec.Mount{
			Source:      filepath.Join(mountPrefix, ctrDir),
			Destination: ctrDir,
			Type:        "bind",
			Options:     []string{"bind", "rprivate"},
		}

		mounts = append(mounts, m)
	}
	return mounts, nil
}

// addFIPSModeSecret creates /run/secrets/system-fips in the container
// root filesystem if /etc/system-fips exists on hosts.
// This enables the container to be FIPS compliant and run openssl in
// FIPS mode as the host is also in FIPS mode.
func addFIPSModeSecret(mounts *[]rspec.Mount, containerWorkingDir string) error {
	secretsDir := "/run/secrets"
	ctrDirOnHost := filepath.Join(containerWorkingDir, secretsDir)
	if _, err := os.Stat(ctrDirOnHost); os.IsNotExist(err) {
		if err = os.MkdirAll(ctrDirOnHost, 0755); err != nil {
			return errors.Wrapf(err, "making container directory on host failed")
		}
	}
	fipsFile := filepath.Join(ctrDirOnHost, "system-fips")
	// In the event of restart, it is possible for the FIPS mode file to already exist
	if _, err := os.Stat(fipsFile); os.IsNotExist(err) {
		file, err := os.Create(fipsFile)
		if err != nil {
			return errors.Wrapf(err, "error creating system-fips file in container for FIPS mode")
		}
		defer file.Close()
	}

	if !mountExists(*mounts, secretsDir) {
		m := rspec.Mount{
			Source:      ctrDirOnHost,
			Destination: secretsDir,
			Type:        "bind",
			Options:     []string{"bind", "rprivate"},
		}
		*mounts = append(*mounts, m)
	}

	return nil
}

// mountExists checks if a mount already exists in the spec
func mountExists(mounts []rspec.Mount, dest string) bool {
	for _, mount := range mounts {
		if mount.Destination == dest {
			return true
		}
	}
	return false
}

// resolveSymbolicLink resolves a possbile symlink path. If the path is a symlink, returns resolved
// path; if not, returns the original path.
func resolveSymbolicLink(path string) (string, error) {
	info, err := os.Lstat(path)
	if err != nil {
		return "", err
	}
	if info.Mode()&os.ModeSymlink != os.ModeSymlink {
		return path, nil
	}
	return filepath.EvalSymlinks(path)
}