forked from containers/buildah
-
Notifications
You must be signed in to change notification settings - Fork 1
/
image.go
1310 lines (1245 loc) · 45.6 KB
/
image.go
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
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
package buildah
import (
"archive/tar"
"bytes"
"context"
"encoding/json"
"errors"
"fmt"
"io"
"os"
"path/filepath"
"strings"
"time"
"github.com/containers/buildah/copier"
"github.com/containers/buildah/define"
"github.com/containers/buildah/docker"
"github.com/containers/buildah/internal/config"
"github.com/containers/buildah/internal/mkcw"
"github.com/containers/buildah/internal/tmpdir"
"github.com/containers/image/v5/docker/reference"
"github.com/containers/image/v5/image"
"github.com/containers/image/v5/manifest"
is "github.com/containers/image/v5/storage"
"github.com/containers/image/v5/types"
"github.com/containers/storage"
"github.com/containers/storage/pkg/archive"
"github.com/containers/storage/pkg/chrootarchive"
"github.com/containers/storage/pkg/idtools"
"github.com/containers/storage/pkg/ioutils"
digest "github.com/opencontainers/go-digest"
specs "github.com/opencontainers/image-spec/specs-go"
v1 "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/sirupsen/logrus"
"golang.org/x/exp/maps"
"golang.org/x/exp/slices"
)
const (
// OCIv1ImageManifest is the MIME type of an OCIv1 image manifest,
// suitable for specifying as a value of the PreferredManifestType
// member of a CommitOptions structure. It is also the default.
OCIv1ImageManifest = define.OCIv1ImageManifest
// Dockerv2ImageManifest is the MIME type of a Docker v2s2 image
// manifest, suitable for specifying as a value of the
// PreferredManifestType member of a CommitOptions structure.
Dockerv2ImageManifest = define.Dockerv2ImageManifest
)
// ExtractRootfsOptions is consumed by ExtractRootfs() which allows users to
// control whether various information like the like setuid and setgid bits and
// xattrs are preserved when extracting file system objects.
type ExtractRootfsOptions struct {
StripSetuidBit bool // strip the setuid bit off of items being extracted.
StripSetgidBit bool // strip the setgid bit off of items being extracted.
StripXattrs bool // don't record extended attributes of items being extracted.
}
type containerImageRef struct {
fromImageName string
fromImageID string
store storage.Store
compression archive.Compression
name reference.Named
names []string
containerID string
mountLabel string
layerID string
oconfig []byte
dconfig []byte
created *time.Time
createdBy string
historyComment string
annotations map[string]string
preferredManifestType string
squash bool
confidentialWorkload ConfidentialWorkloadOptions
omitHistory bool
emptyLayer bool
idMappingOptions *define.IDMappingOptions
parent string
blobDirectory string
preEmptyLayers []v1.History
preLayers []commitLinkedLayerInfo
postEmptyLayers []v1.History
postLayers []commitLinkedLayerInfo
overrideChanges []string
overrideConfig *manifest.Schema2Config
extraImageContent map[string]string
compatSetParent types.OptionalBool
}
type blobLayerInfo struct {
ID string
Size int64
}
type commitLinkedLayerInfo struct {
layerID string // more like layer "ID"
linkedLayer LinkedLayer
uncompressedDigest digest.Digest
size int64
}
type containerImageSource struct {
path string
ref *containerImageRef
store storage.Store
containerID string
mountLabel string
layerID string
names []string
compression archive.Compression
config []byte
configDigest digest.Digest
manifest []byte
manifestType string
blobDirectory string
blobLayers map[digest.Digest]blobLayerInfo
}
func (i *containerImageRef) NewImage(ctx context.Context, sc *types.SystemContext) (types.ImageCloser, error) {
src, err := i.NewImageSource(ctx, sc)
if err != nil {
return nil, err
}
return image.FromSource(ctx, sc, src)
}
func expectedOCIDiffIDs(image v1.Image) int {
expected := 0
for _, history := range image.History {
if !history.EmptyLayer {
expected = expected + 1
}
}
return expected
}
func expectedDockerDiffIDs(image docker.V2Image) int {
expected := 0
for _, history := range image.History {
if !history.EmptyLayer {
expected = expected + 1
}
}
return expected
}
// Compute the media types which we need to attach to a layer, given the type of
// compression that we'll be applying.
func computeLayerMIMEType(what string, layerCompression archive.Compression) (omediaType, dmediaType string, err error) {
omediaType = v1.MediaTypeImageLayer
dmediaType = docker.V2S2MediaTypeUncompressedLayer
if layerCompression != archive.Uncompressed {
switch layerCompression {
case archive.Gzip:
omediaType = v1.MediaTypeImageLayerGzip
dmediaType = manifest.DockerV2Schema2LayerMediaType
logrus.Debugf("compressing %s with gzip", what)
case archive.Bzip2:
// Until the image specs define a media type for bzip2-compressed layers, even if we know
// how to decompress them, we can't try to compress layers with bzip2.
return "", "", errors.New("media type for bzip2-compressed layers is not defined")
case archive.Xz:
// Until the image specs define a media type for xz-compressed layers, even if we know
// how to decompress them, we can't try to compress layers with xz.
return "", "", errors.New("media type for xz-compressed layers is not defined")
case archive.Zstd:
// Until the image specs define a media type for zstd-compressed layers, even if we know
// how to decompress them, we can't try to compress layers with zstd.
return "", "", errors.New("media type for zstd-compressed layers is not defined")
default:
logrus.Debugf("compressing %s with unknown compressor(?)", what)
}
}
return omediaType, dmediaType, nil
}
// Extract the container's whole filesystem as a filesystem image, wrapped
// in LUKS-compatible encryption.
func (i *containerImageRef) extractConfidentialWorkloadFS(options ConfidentialWorkloadOptions) (io.ReadCloser, error) {
var image v1.Image
if err := json.Unmarshal(i.oconfig, &image); err != nil {
return nil, fmt.Errorf("recreating OCI configuration for %q: %w", i.containerID, err)
}
if options.TempDir == "" {
cdir, err := i.store.ContainerDirectory(i.containerID)
if err != nil {
return nil, fmt.Errorf("getting the per-container data directory for %q: %w", i.containerID, err)
}
tempdir, err := os.MkdirTemp(cdir, "buildah-rootfs")
if err != nil {
return nil, fmt.Errorf("creating a temporary data directory to hold a rootfs image for %q: %w", i.containerID, err)
}
defer func() {
if err := os.RemoveAll(tempdir); err != nil {
logrus.Warnf("removing temporary directory %q: %v", tempdir, err)
}
}()
options.TempDir = tempdir
}
mountPoint, err := i.store.Mount(i.containerID, i.mountLabel)
if err != nil {
return nil, fmt.Errorf("mounting container %q: %w", i.containerID, err)
}
archiveOptions := mkcw.ArchiveOptions{
AttestationURL: options.AttestationURL,
CPUs: options.CPUs,
Memory: options.Memory,
TempDir: options.TempDir,
TeeType: options.TeeType,
IgnoreAttestationErrors: options.IgnoreAttestationErrors,
WorkloadID: options.WorkloadID,
DiskEncryptionPassphrase: options.DiskEncryptionPassphrase,
Slop: options.Slop,
FirmwareLibrary: options.FirmwareLibrary,
GraphOptions: i.store.GraphOptions(),
ExtraImageContent: i.extraImageContent,
}
rc, _, err := mkcw.Archive(mountPoint, &image, archiveOptions)
if err != nil {
if _, err2 := i.store.Unmount(i.containerID, false); err2 != nil {
logrus.Debugf("unmounting container %q: %v", i.containerID, err2)
}
return nil, fmt.Errorf("converting rootfs %q: %w", i.containerID, err)
}
return ioutils.NewReadCloserWrapper(rc, func() error {
if err = rc.Close(); err != nil {
err = fmt.Errorf("closing tar archive of container %q: %w", i.containerID, err)
}
if _, err2 := i.store.Unmount(i.containerID, false); err == nil {
if err2 != nil {
err2 = fmt.Errorf("unmounting container %q: %w", i.containerID, err2)
}
err = err2
} else {
logrus.Debugf("unmounting container %q: %v", i.containerID, err2)
}
return err
}), nil
}
// Extract the container's whole filesystem as if it were a single layer.
// The ExtractRootfsOptions control whether or not to preserve setuid and
// setgid bits and extended attributes on contents.
func (i *containerImageRef) extractRootfs(opts ExtractRootfsOptions) (io.ReadCloser, chan error, error) {
var uidMap, gidMap []idtools.IDMap
mountPoint, err := i.store.Mount(i.containerID, i.mountLabel)
if err != nil {
return nil, nil, fmt.Errorf("mounting container %q: %w", i.containerID, err)
}
pipeReader, pipeWriter := io.Pipe()
errChan := make(chan error, 1)
go func() {
defer close(errChan)
if len(i.extraImageContent) > 0 {
// Abuse the tar format and _prepend_ the synthesized
// data items to the archive we'll get from
// copier.Get(), in a way that looks right to a reader
// as long as we DON'T Close() the tar Writer.
filename, _, _, err := i.makeExtraImageContentDiff(false)
if err != nil {
errChan <- err
return
}
file, err := os.Open(filename)
if err != nil {
errChan <- err
return
}
defer file.Close()
if _, err = io.Copy(pipeWriter, file); err != nil {
errChan <- err
return
}
}
if i.idMappingOptions != nil {
uidMap, gidMap = convertRuntimeIDMaps(i.idMappingOptions.UIDMap, i.idMappingOptions.GIDMap)
}
copierOptions := copier.GetOptions{
UIDMap: uidMap,
GIDMap: gidMap,
StripSetuidBit: opts.StripSetuidBit,
StripSetgidBit: opts.StripSetgidBit,
StripXattrs: opts.StripXattrs,
}
err := copier.Get(mountPoint, mountPoint, copierOptions, []string{"."}, pipeWriter)
errChan <- err
pipeWriter.Close()
}()
return ioutils.NewReadCloserWrapper(pipeReader, func() error {
if err = pipeReader.Close(); err != nil {
err = fmt.Errorf("closing tar archive of container %q: %w", i.containerID, err)
}
if _, err2 := i.store.Unmount(i.containerID, false); err == nil {
if err2 != nil {
err2 = fmt.Errorf("unmounting container %q: %w", i.containerID, err2)
}
err = err2
}
return err
}), errChan, nil
}
// Build fresh copies of the container configuration structures so that we can edit them
// without making unintended changes to the original Builder.
func (i *containerImageRef) createConfigsAndManifests() (v1.Image, v1.Manifest, docker.V2Image, docker.V2S2Manifest, error) {
created := time.Now().UTC()
if i.created != nil {
created = *i.created
}
// Build an empty image, and then decode over it.
oimage := v1.Image{}
if err := json.Unmarshal(i.oconfig, &oimage); err != nil {
return v1.Image{}, v1.Manifest{}, docker.V2Image{}, docker.V2S2Manifest{}, err
}
// Always replace this value, since we're newer than our base image.
oimage.Created = &created
// Clear the list of diffIDs, since we always repopulate it.
oimage.RootFS.Type = docker.TypeLayers
oimage.RootFS.DiffIDs = []digest.Digest{}
// Only clear the history if we're squashing, otherwise leave it be so that we can append
// entries to it.
if i.confidentialWorkload.Convert || i.squash || i.omitHistory {
oimage.History = []v1.History{}
}
// Build an empty image, and then decode over it.
dimage := docker.V2Image{}
if err := json.Unmarshal(i.dconfig, &dimage); err != nil {
return v1.Image{}, v1.Manifest{}, docker.V2Image{}, docker.V2S2Manifest{}, err
}
// Set the parent, but only if we want to be compatible with "classic" docker build.
if i.compatSetParent == types.OptionalBoolTrue {
dimage.Parent = docker.ID(i.parent)
}
// Set the container ID and containerConfig in the docker format.
dimage.Container = i.containerID
if dimage.Config != nil {
dimage.ContainerConfig = *dimage.Config
}
// Always replace this value, since we're newer than our base image.
dimage.Created = created
// Clear the list of diffIDs, since we always repopulate it.
dimage.RootFS = &docker.V2S2RootFS{}
dimage.RootFS.Type = docker.TypeLayers
dimage.RootFS.DiffIDs = []digest.Digest{}
// Only clear the history if we're squashing, otherwise leave it be so
// that we can append entries to it. Clear the parent, too, to reflect
// that we no longer include its layers and history.
if i.confidentialWorkload.Convert || i.squash || i.omitHistory {
dimage.Parent = ""
dimage.History = []docker.V2S2History{}
}
// If we were supplied with a configuration, copy fields from it to
// matching fields in both formats.
if err := config.Override(dimage.Config, &oimage.Config, i.overrideChanges, i.overrideConfig); err != nil {
return v1.Image{}, v1.Manifest{}, docker.V2Image{}, docker.V2S2Manifest{}, fmt.Errorf("applying changes: %w", err)
}
// If we're producing a confidential workload, override the command and
// assorted other settings that aren't expected to work correctly.
if i.confidentialWorkload.Convert {
dimage.Config.Entrypoint = []string{"/entrypoint"}
oimage.Config.Entrypoint = []string{"/entrypoint"}
dimage.Config.Cmd = nil
oimage.Config.Cmd = nil
dimage.Config.User = ""
oimage.Config.User = ""
dimage.Config.WorkingDir = ""
oimage.Config.WorkingDir = ""
dimage.Config.Healthcheck = nil
dimage.Config.Shell = nil
dimage.Config.Volumes = nil
oimage.Config.Volumes = nil
dimage.Config.ExposedPorts = nil
oimage.Config.ExposedPorts = nil
}
// Build empty manifests. The Layers lists will be populated later.
omanifest := v1.Manifest{
Versioned: specs.Versioned{
SchemaVersion: 2,
},
MediaType: v1.MediaTypeImageManifest,
Config: v1.Descriptor{
MediaType: v1.MediaTypeImageConfig,
},
Layers: []v1.Descriptor{},
Annotations: i.annotations,
}
dmanifest := docker.V2S2Manifest{
V2Versioned: docker.V2Versioned{
SchemaVersion: 2,
MediaType: manifest.DockerV2Schema2MediaType,
},
Config: docker.V2S2Descriptor{
MediaType: manifest.DockerV2Schema2ConfigMediaType,
},
Layers: []docker.V2S2Descriptor{},
}
return oimage, omanifest, dimage, dmanifest, nil
}
func (i *containerImageRef) NewImageSource(_ context.Context, _ *types.SystemContext) (src types.ImageSource, err error) {
// Decide which type of manifest and configuration output we're going to provide.
manifestType := i.preferredManifestType
// If it's not a format we support, return an error.
if manifestType != v1.MediaTypeImageManifest && manifestType != manifest.DockerV2Schema2MediaType {
return nil, fmt.Errorf("no supported manifest types (attempted to use %q, only know %q and %q)",
manifestType, v1.MediaTypeImageManifest, manifest.DockerV2Schema2MediaType)
}
// These maps will let us check if a layer ID is part of one group or another.
parentLayerIDs := make(map[string]bool)
apiLayerIDs := make(map[string]bool)
// Start building the list of layers with any prepended layers.
layers := []string{}
for _, preLayer := range i.preLayers {
layers = append(layers, preLayer.layerID)
apiLayerIDs[preLayer.layerID] = true
}
// Now look at the read-write layer, and prepare to work our way back
// through all of its parent layers.
layerID := i.layerID
layer, err := i.store.Layer(layerID)
if err != nil {
return nil, fmt.Errorf("unable to read layer %q: %w", layerID, err)
}
// Walk the list of parent layers, prepending each as we go. If we're squashing
// or making a confidential workload, we're only producing one layer, so stop at
// the layer ID of the top layer, which we won't really be using anyway.
for layer != nil {
if layerID == i.layerID {
// append the layer for this container to the list,
// whether it's first or after some prepended layers
layers = append(layers, layerID)
} else {
// prepend this parent layer to the list
layers = append(append([]string{}, layerID), layers...)
parentLayerIDs[layerID] = true
}
layerID = layer.Parent
if layerID == "" || i.confidentialWorkload.Convert || i.squash {
err = nil
break
}
layer, err = i.store.Layer(layerID)
if err != nil {
return nil, fmt.Errorf("unable to read layer %q: %w", layerID, err)
}
}
layer = nil
// If we're slipping in a synthesized layer to hold some files, we need
// to add a placeholder for it to the list just after the read-write
// layer. Confidential workloads and squashed images will just inline
// the files, so we don't need to create a layer in those cases.
const synthesizedLayerID = "(synthesized layer)"
if len(i.extraImageContent) > 0 && !i.confidentialWorkload.Convert && !i.squash {
layers = append(layers, synthesizedLayerID)
}
// Now add any API-supplied layers we have to append.
for _, postLayer := range i.postLayers {
layers = append(layers, postLayer.layerID)
apiLayerIDs[postLayer.layerID] = true
}
logrus.Debugf("layer list: %q", layers)
// It's simpler from here on to keep track of these as a group.
apiLayers := append(slices.Clone(i.preLayers), slices.Clone(i.postLayers)...)
// Make a temporary directory to hold blobs.
path, err := os.MkdirTemp(tmpdir.GetTempDir(), define.Package)
if err != nil {
return nil, fmt.Errorf("creating temporary directory to hold layer blobs: %w", err)
}
logrus.Debugf("using %q to hold temporary data", path)
defer func() {
if src == nil {
err2 := os.RemoveAll(path)
if err2 != nil {
logrus.Errorf("error removing layer blob directory: %v", err)
}
}
}()
// Build fresh copies of the configurations and manifest so that we don't mess with any
// values in the Builder object itself.
oimage, omanifest, dimage, dmanifest, err := i.createConfigsAndManifests()
if err != nil {
return nil, err
}
// Extract each layer and compute its digests, both compressed (if requested) and uncompressed.
var extraImageContentDiff string
var extraImageContentDiffDigest digest.Digest
blobLayers := make(map[digest.Digest]blobLayerInfo)
for _, layerID := range layers {
what := fmt.Sprintf("layer %q", layerID)
if i.confidentialWorkload.Convert || i.squash {
what = fmt.Sprintf("container %q", i.containerID)
}
if layerID == synthesizedLayerID {
what = synthesizedLayerID
}
if apiLayerIDs[layerID] {
what = layerID
}
// The default layer media type assumes no compression.
omediaType := v1.MediaTypeImageLayer
dmediaType := docker.V2S2MediaTypeUncompressedLayer
// Look up this layer.
var layerUncompressedDigest digest.Digest
var layerUncompressedSize int64
linkedLayerHasLayerID := func(l commitLinkedLayerInfo) bool { return l.layerID == layerID }
if apiLayerIDs[layerID] {
// API-provided prepended or appended layer
apiLayerIndex := slices.IndexFunc(apiLayers, linkedLayerHasLayerID)
layerUncompressedDigest = apiLayers[apiLayerIndex].uncompressedDigest
layerUncompressedSize = apiLayers[apiLayerIndex].size
} else if layerID == synthesizedLayerID {
// layer diff consisting of extra files to synthesize into a layer
diffFilename, digest, size, err := i.makeExtraImageContentDiff(true)
if err != nil {
return nil, fmt.Errorf("unable to generate layer for additional content: %w", err)
}
extraImageContentDiff = diffFilename
extraImageContentDiffDigest = digest
layerUncompressedDigest = digest
layerUncompressedSize = size
} else {
// "normal" layer
layer, err := i.store.Layer(layerID)
if err != nil {
return nil, fmt.Errorf("unable to locate layer %q: %w", layerID, err)
}
layerID = layer.ID
layerUncompressedDigest = layer.UncompressedDigest
layerUncompressedSize = layer.UncompressedSize
}
// We already know the digest of the contents of parent layers,
// so if this is a parent layer, and we know its digest, reuse
// its blobsum, diff ID, and size.
if !i.confidentialWorkload.Convert && !i.squash && parentLayerIDs[layerID] && layerUncompressedDigest != "" {
layerBlobSum := layerUncompressedDigest
layerBlobSize := layerUncompressedSize
diffID := layerUncompressedDigest
// Note this layer in the manifest, using the appropriate blobsum.
olayerDescriptor := v1.Descriptor{
MediaType: omediaType,
Digest: layerBlobSum,
Size: layerBlobSize,
}
omanifest.Layers = append(omanifest.Layers, olayerDescriptor)
dlayerDescriptor := docker.V2S2Descriptor{
MediaType: dmediaType,
Digest: layerBlobSum,
Size: layerBlobSize,
}
dmanifest.Layers = append(dmanifest.Layers, dlayerDescriptor)
// Note this layer in the list of diffIDs, again using the uncompressed digest.
oimage.RootFS.DiffIDs = append(oimage.RootFS.DiffIDs, diffID)
dimage.RootFS.DiffIDs = append(dimage.RootFS.DiffIDs, diffID)
blobLayers[diffID] = blobLayerInfo{
ID: layerID,
Size: layerBlobSize,
}
continue
}
// Figure out if we need to change the media type, in case we've changed the compression.
omediaType, dmediaType, err = computeLayerMIMEType(what, i.compression)
if err != nil {
return nil, err
}
// Start reading either the layer or the whole container rootfs.
noCompression := archive.Uncompressed
diffOptions := &storage.DiffOptions{
Compression: &noCompression,
}
var rc io.ReadCloser
var errChan chan error
if i.confidentialWorkload.Convert {
// Convert the root filesystem into an encrypted disk image.
rc, err = i.extractConfidentialWorkloadFS(i.confidentialWorkload)
if err != nil {
return nil, err
}
} else if i.squash {
// Extract the root filesystem as a single layer.
rc, errChan, err = i.extractRootfs(ExtractRootfsOptions{})
if err != nil {
return nil, err
}
} else {
if apiLayerIDs[layerID] {
// We're reading an API-supplied blob.
apiLayerIndex := slices.IndexFunc(apiLayers, linkedLayerHasLayerID)
f, err := os.Open(apiLayers[apiLayerIndex].linkedLayer.BlobPath)
if err != nil {
return nil, fmt.Errorf("opening layer blob for %s: %w", layerID, err)
}
rc = f
} else if layerID == synthesizedLayerID {
// Slip in additional content as an additional layer.
if rc, err = os.Open(extraImageContentDiff); err != nil {
return nil, err
}
} else {
// If we're up to the final layer, but we don't want to
// include a diff for it, we're done.
if i.emptyLayer && layerID == i.layerID {
continue
}
// Extract this layer, one of possibly many.
rc, err = i.store.Diff("", layerID, diffOptions)
if err != nil {
return nil, fmt.Errorf("extracting %s: %w", what, err)
}
}
}
srcHasher := digest.Canonical.Digester()
// Set up to write the possibly-recompressed blob.
layerFile, err := os.OpenFile(filepath.Join(path, "layer"), os.O_CREATE|os.O_WRONLY, 0o600)
if err != nil {
rc.Close()
return nil, fmt.Errorf("opening file for %s: %w", what, err)
}
counter := ioutils.NewWriteCounter(layerFile)
var destHasher digest.Digester
var multiWriter io.Writer
// Avoid rehashing when we do not compress.
if i.compression != archive.Uncompressed {
destHasher = digest.Canonical.Digester()
multiWriter = io.MultiWriter(counter, destHasher.Hash())
} else {
destHasher = srcHasher
multiWriter = counter
}
// Compress the layer, if we're recompressing it.
writeCloser, err := archive.CompressStream(multiWriter, i.compression)
if err != nil {
layerFile.Close()
rc.Close()
return nil, fmt.Errorf("compressing %s: %w", what, err)
}
writer := io.MultiWriter(writeCloser, srcHasher.Hash())
{
// Tweak the contents of layers we're creating.
nestedWriteCloser := ioutils.NewWriteCloserWrapper(writer, writeCloser.Close)
writeCloser = newTarFilterer(nestedWriteCloser, func(hdr *tar.Header) (bool, bool, io.Reader) {
// Scrub any local user names that might correspond to UIDs or GIDs of
// files in this layer.
hdr.Uname, hdr.Gname = "", ""
// Use specified timestamps in the layer, if we're doing that for history
// entries.
if i.created != nil {
// Changing a zeroed field to a non-zero field can affect the
// format that the library uses for writing the header, so only
// change fields that are already set to avoid changing the
// format (and as a result, changing the length) of the header
// that we write.
if !hdr.ModTime.IsZero() {
hdr.ModTime = *i.created
}
if !hdr.AccessTime.IsZero() {
hdr.AccessTime = *i.created
}
if !hdr.ChangeTime.IsZero() {
hdr.ChangeTime = *i.created
}
return false, false, nil
}
return false, false, nil
})
writer = io.Writer(writeCloser)
}
// Okay, copy from the raw diff through the filter, compressor, and counter and
// digesters.
size, err := io.Copy(writer, rc)
if err := writeCloser.Close(); err != nil {
layerFile.Close()
rc.Close()
return nil, fmt.Errorf("storing %s to file: %w on pipe close", what, err)
}
if err := layerFile.Close(); err != nil {
rc.Close()
return nil, fmt.Errorf("storing %s to file: %w on file close", what, err)
}
rc.Close()
if errChan != nil {
err = <-errChan
if err != nil {
return nil, fmt.Errorf("extracting container rootfs: %w", err)
}
}
if err != nil {
return nil, fmt.Errorf("storing %s to file: %w", what, err)
}
if i.compression == archive.Uncompressed {
if size != counter.Count {
return nil, fmt.Errorf("storing %s to file: inconsistent layer size (copied %d, wrote %d)", what, size, counter.Count)
}
} else {
size = counter.Count
}
logrus.Debugf("%s size is %d bytes, uncompressed digest %s, possibly-compressed digest %s", what, size, srcHasher.Digest().String(), destHasher.Digest().String())
// Rename the layer so that we can more easily find it by digest later.
finalBlobName := filepath.Join(path, destHasher.Digest().String())
if err = os.Rename(filepath.Join(path, "layer"), finalBlobName); err != nil {
return nil, fmt.Errorf("storing %s to file while renaming %q to %q: %w", what, filepath.Join(path, "layer"), finalBlobName, err)
}
// Add a note in the manifest about the layer. The blobs are identified by their possibly-
// compressed blob digests.
olayerDescriptor := v1.Descriptor{
MediaType: omediaType,
Digest: destHasher.Digest(),
Size: size,
}
omanifest.Layers = append(omanifest.Layers, olayerDescriptor)
dlayerDescriptor := docker.V2S2Descriptor{
MediaType: dmediaType,
Digest: destHasher.Digest(),
Size: size,
}
dmanifest.Layers = append(dmanifest.Layers, dlayerDescriptor)
// Add a note about the diffID, which is always the layer's uncompressed digest.
oimage.RootFS.DiffIDs = append(oimage.RootFS.DiffIDs, srcHasher.Digest())
dimage.RootFS.DiffIDs = append(dimage.RootFS.DiffIDs, srcHasher.Digest())
}
// Build history notes in the image configurations.
appendHistory := func(history []v1.History, empty bool) {
for i := range history {
var created *time.Time
if history[i].Created != nil {
copiedTimestamp := *history[i].Created
created = &copiedTimestamp
}
onews := v1.History{
Created: created,
CreatedBy: history[i].CreatedBy,
Author: history[i].Author,
Comment: history[i].Comment,
EmptyLayer: empty,
}
oimage.History = append(oimage.History, onews)
if created == nil {
created = &time.Time{}
}
dnews := docker.V2S2History{
Created: *created,
CreatedBy: history[i].CreatedBy,
Author: history[i].Author,
Comment: history[i].Comment,
EmptyLayer: empty,
}
dimage.History = append(dimage.History, dnews)
}
}
// Only attempt to append history if history was not disabled explicitly.
if !i.omitHistory {
// Keep track of how many entries the base image's history had
// before we started adding to it.
baseImageHistoryLen := len(oimage.History)
// Add history entries for prepended empty layers.
appendHistory(i.preEmptyLayers, true)
// Add history entries for prepended API-supplied layers.
for _, h := range i.preLayers {
appendHistory([]v1.History{h.linkedLayer.History}, h.linkedLayer.History.EmptyLayer)
}
// Add a history entry for this layer, empty or not.
created := time.Now().UTC()
if i.created != nil {
created = (*i.created).UTC()
}
onews := v1.History{
Created: &created,
CreatedBy: i.createdBy,
Author: oimage.Author,
EmptyLayer: i.emptyLayer,
Comment: i.historyComment,
}
oimage.History = append(oimage.History, onews)
dnews := docker.V2S2History{
Created: created,
CreatedBy: i.createdBy,
Author: dimage.Author,
EmptyLayer: i.emptyLayer,
Comment: i.historyComment,
}
dimage.History = append(dimage.History, dnews)
// Add a history entry for the extra image content if we added a layer for it.
// This diff was added to the list of layers before API-supplied layers that
// needed to be appended, and we need to keep the order of history entries for
// not-empty layers consistent with that.
if extraImageContentDiff != "" {
createdBy := fmt.Sprintf(`/bin/sh -c #(nop) ADD dir:%s in /",`, extraImageContentDiffDigest.Encoded())
onews := v1.History{
Created: &created,
CreatedBy: createdBy,
}
oimage.History = append(oimage.History, onews)
dnews := docker.V2S2History{
Created: created,
CreatedBy: createdBy,
}
dimage.History = append(dimage.History, dnews)
}
// Add history entries for appended empty layers.
appendHistory(i.postEmptyLayers, true)
// Add history entries for appended API-supplied layers.
for _, h := range i.postLayers {
appendHistory([]v1.History{h.linkedLayer.History}, h.linkedLayer.History.EmptyLayer)
}
// Assemble a comment indicating which base image was used, if it wasn't
// just an image ID, and add it to the first history entry we added.
var fromComment string
if strings.Contains(i.parent, i.fromImageID) && i.fromImageName != "" && !strings.HasPrefix(i.fromImageID, i.fromImageName) {
if oimage.History[baseImageHistoryLen].Comment != "" {
fromComment = " "
}
fromComment += "FROM " + i.fromImageName
}
oimage.History[baseImageHistoryLen].Comment += fromComment
dimage.History[baseImageHistoryLen].Comment += fromComment
// Confidence check that we didn't just create a mismatch between non-empty layers in the
// history and the number of diffIDs. Only applicable if the base image (if there was
// one) provided us at least one entry to use as a starting point.
if baseImageHistoryLen != 0 {
expectedDiffIDs := expectedOCIDiffIDs(oimage)
if len(oimage.RootFS.DiffIDs) != expectedDiffIDs {
return nil, fmt.Errorf("internal error: history lists %d non-empty layers, but we have %d layers on disk", expectedDiffIDs, len(oimage.RootFS.DiffIDs))
}
expectedDiffIDs = expectedDockerDiffIDs(dimage)
if len(dimage.RootFS.DiffIDs) != expectedDiffIDs {
return nil, fmt.Errorf("internal error: history lists %d non-empty layers, but we have %d layers on disk", expectedDiffIDs, len(dimage.RootFS.DiffIDs))
}
}
}
// Encode the image configuration blob.
oconfig, err := json.Marshal(&oimage)
if err != nil {
return nil, fmt.Errorf("encoding %#v as json: %w", oimage, err)
}
logrus.Debugf("OCIv1 config = %s", oconfig)
// Add the configuration blob to the manifest.
omanifest.Config.Digest = digest.Canonical.FromBytes(oconfig)
omanifest.Config.Size = int64(len(oconfig))
omanifest.Config.MediaType = v1.MediaTypeImageConfig
// Encode the manifest.
omanifestbytes, err := json.Marshal(&omanifest)
if err != nil {
return nil, fmt.Errorf("encoding %#v as json: %w", omanifest, err)
}
logrus.Debugf("OCIv1 manifest = %s", omanifestbytes)
// Encode the image configuration blob.
dconfig, err := json.Marshal(&dimage)
if err != nil {
return nil, fmt.Errorf("encoding %#v as json: %w", dimage, err)
}
logrus.Debugf("Docker v2s2 config = %s", dconfig)
// Add the configuration blob to the manifest.
dmanifest.Config.Digest = digest.Canonical.FromBytes(dconfig)
dmanifest.Config.Size = int64(len(dconfig))
dmanifest.Config.MediaType = manifest.DockerV2Schema2ConfigMediaType
// Encode the manifest.
dmanifestbytes, err := json.Marshal(&dmanifest)
if err != nil {
return nil, fmt.Errorf("encoding %#v as json: %w", dmanifest, err)
}
logrus.Debugf("Docker v2s2 manifest = %s", dmanifestbytes)
// Decide which manifest and configuration blobs we'll actually output.
var config []byte
var imageManifest []byte
switch manifestType {
case v1.MediaTypeImageManifest:
imageManifest = omanifestbytes
config = oconfig
case manifest.DockerV2Schema2MediaType:
imageManifest = dmanifestbytes
config = dconfig
default:
panic("unreachable code: unsupported manifest type")
}
src = &containerImageSource{
path: path,
ref: i,
store: i.store,
containerID: i.containerID,
mountLabel: i.mountLabel,
layerID: i.layerID,
names: i.names,
compression: i.compression,
config: config,
configDigest: digest.Canonical.FromBytes(config),
manifest: imageManifest,
manifestType: manifestType,
blobDirectory: i.blobDirectory,
blobLayers: blobLayers,
}
return src, nil
}
func (i *containerImageRef) NewImageDestination(_ context.Context, _ *types.SystemContext) (types.ImageDestination, error) {
return nil, errors.New("can't write to a container")
}
func (i *containerImageRef) DockerReference() reference.Named {
return i.name
}
func (i *containerImageRef) StringWithinTransport() string {
if len(i.names) > 0 {
return i.names[0]
}
return ""
}
func (i *containerImageRef) DeleteImage(context.Context, *types.SystemContext) error {
// we were never here
return nil
}
func (i *containerImageRef) PolicyConfigurationIdentity() string {
return ""
}
func (i *containerImageRef) PolicyConfigurationNamespaces() []string {
return nil
}
func (i *containerImageRef) Transport() types.ImageTransport {
return is.Transport
}
func (i *containerImageSource) Close() error {
err := os.RemoveAll(i.path)
if err != nil {
return fmt.Errorf("removing layer blob directory: %w", err)
}
return nil
}
func (i *containerImageSource) Reference() types.ImageReference {
return i.ref
}
func (i *containerImageSource) GetSignatures(_ context.Context, _ *digest.Digest) ([][]byte, error) {
return nil, nil
}
func (i *containerImageSource) GetManifest(_ context.Context, _ *digest.Digest) ([]byte, string, error) {
return i.manifest, i.manifestType, nil
}
func (i *containerImageSource) LayerInfosForCopy(_ context.Context, _ *digest.Digest) ([]types.BlobInfo, error) {
return nil, nil
}
func (i *containerImageSource) HasThreadSafeGetBlob() bool {
return false
}
func (i *containerImageSource) GetBlob(_ context.Context, blob types.BlobInfo, _ types.BlobInfoCache) (reader io.ReadCloser, size int64, err error) {
if blob.Digest == i.configDigest {
logrus.Debugf("start reading config")
reader := bytes.NewReader(i.config)
closer := func() error {
logrus.Debugf("finished reading config")
return nil
}
return ioutils.NewReadCloserWrapper(reader, closer), reader.Size(), nil
}
var layerReadCloser io.ReadCloser
size = -1
if blobLayerInfo, ok := i.blobLayers[blob.Digest]; ok {
noCompression := archive.Uncompressed
diffOptions := &storage.DiffOptions{
Compression: &noCompression,
}