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
|
package copy
import (
"bytes"
"context"
"errors"
"fmt"
"strings"
"github.com/containers/image/v5/docker/reference"
"github.com/containers/image/v5/internal/image"
internalManifest "github.com/containers/image/v5/internal/manifest"
"github.com/containers/image/v5/manifest"
"github.com/containers/image/v5/signature"
digest "github.com/opencontainers/go-digest"
imgspecv1 "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/sirupsen/logrus"
"golang.org/x/exp/slices"
)
type instanceCopyKind int
const (
instanceCopyCopy instanceCopyKind = iota
instanceCopyClone
)
type instanceCopy struct {
op instanceCopyKind
sourceDigest digest.Digest
}
// prepareInstanceCopies prepares a list of instances which needs to copied to the manifest list.
func prepareInstanceCopies(instanceDigests []digest.Digest, options *Options) []instanceCopy {
res := []instanceCopy{}
for i, instanceDigest := range instanceDigests {
if options.ImageListSelection == CopySpecificImages &&
!slices.Contains(options.Instances, instanceDigest) {
logrus.Debugf("Skipping instance %s (%d/%d)", instanceDigest, i+1, len(instanceDigests))
continue
}
res = append(res, instanceCopy{
op: instanceCopyCopy,
sourceDigest: instanceDigest,
})
}
return res
}
// copyMultipleImages copies some or all of an image list's instances, using
// policyContext to validate source image admissibility.
func (c *copier) copyMultipleImages(ctx context.Context, policyContext *signature.PolicyContext, options *Options, unparsedToplevel *image.UnparsedImage) (copiedManifest []byte, retErr error) {
// Parse the list and get a copy of the original value after it's re-encoded.
manifestList, manifestType, err := unparsedToplevel.Manifest(ctx)
if err != nil {
return nil, fmt.Errorf("reading manifest list: %w", err)
}
originalList, err := internalManifest.ListFromBlob(manifestList, manifestType)
if err != nil {
return nil, fmt.Errorf("parsing manifest list %q: %w", string(manifestList), err)
}
updatedList := originalList.CloneInternal()
sigs, err := c.sourceSignatures(ctx, unparsedToplevel, options,
"Getting image list signatures",
"Checking if image list destination supports signatures")
if err != nil {
return nil, err
}
// If the destination is a digested reference, make a note of that, determine what digest value we're
// expecting, and check that the source manifest matches it.
destIsDigestedReference := false
if named := c.dest.Reference().DockerReference(); named != nil {
if digested, ok := named.(reference.Digested); ok {
destIsDigestedReference = true
matches, err := manifest.MatchesDigest(manifestList, digested.Digest())
if err != nil {
return nil, fmt.Errorf("computing digest of source image's manifest: %w", err)
}
if !matches {
return nil, errors.New("Digest of source image's manifest would not match destination reference")
}
}
}
// Determine if we're allowed to modify the manifest list.
// If we can, set to the empty string. If we can't, set to the reason why.
// Compare, and perhaps keep in sync with, the version in copySingleImage.
cannotModifyManifestListReason := ""
if len(sigs) > 0 {
cannotModifyManifestListReason = "Would invalidate signatures"
}
if destIsDigestedReference {
cannotModifyManifestListReason = "Destination specifies a digest"
}
if options.PreserveDigests {
cannotModifyManifestListReason = "Instructed to preserve digests"
}
// Determine if we'll need to convert the manifest list to a different format.
forceListMIMEType := options.ForceManifestMIMEType
switch forceListMIMEType {
case manifest.DockerV2Schema1MediaType, manifest.DockerV2Schema1SignedMediaType, manifest.DockerV2Schema2MediaType:
forceListMIMEType = manifest.DockerV2ListMediaType
case imgspecv1.MediaTypeImageManifest:
forceListMIMEType = imgspecv1.MediaTypeImageIndex
}
selectedListType, otherManifestMIMETypeCandidates, err := c.determineListConversion(manifestType, c.dest.SupportedManifestMIMETypes(), forceListMIMEType)
if err != nil {
return nil, fmt.Errorf("determining manifest list type to write to destination: %w", err)
}
if selectedListType != originalList.MIMEType() {
if cannotModifyManifestListReason != "" {
return nil, fmt.Errorf("Manifest list must be converted to type %q to be written to destination, but we cannot modify it: %q", selectedListType, cannotModifyManifestListReason)
}
}
// Copy each image, or just the ones we want to copy, in turn.
instanceDigests := updatedList.Instances()
instanceEdits := []internalManifest.ListEdit{}
instanceCopyList := prepareInstanceCopies(instanceDigests, options)
c.Printf("Copying %d of %d images in list\n", len(instanceCopyList), len(instanceDigests))
for i, instance := range instanceCopyList {
// Update instances to be edited by their `ListOperation` and
// populate necessary fields.
switch instance.op {
case instanceCopyCopy:
logrus.Debugf("Copying instance %s (%d/%d)", instance.sourceDigest, i+1, len(instanceCopyList))
c.Printf("Copying image %s (%d/%d)\n", instance.sourceDigest, i+1, len(instanceCopyList))
unparsedInstance := image.UnparsedInstance(c.rawSource, &instanceCopyList[i].sourceDigest)
updatedManifest, updatedManifestType, updatedManifestDigest, err := c.copySingleImage(ctx, policyContext, options, unparsedToplevel, unparsedInstance, &instanceCopyList[i].sourceDigest)
if err != nil {
return nil, fmt.Errorf("copying image %d/%d from manifest list: %w", i+1, len(instanceCopyList), err)
}
// Record the result of a possible conversion here.
instanceEdits = append(instanceEdits, internalManifest.ListEdit{
ListOperation: internalManifest.ListOpUpdate,
UpdateOldDigest: instance.sourceDigest,
UpdateDigest: updatedManifestDigest,
UpdateSize: int64(len(updatedManifest)),
UpdateMediaType: updatedManifestType})
default:
return nil, fmt.Errorf("copying image: invalid copy operation %d", instance.op)
}
}
// Now reset the digest/size/types of the manifests in the list to account for any conversions that we made.
if err = updatedList.EditInstances(instanceEdits); err != nil {
return nil, fmt.Errorf("updating manifest list: %w", err)
}
// Iterate through supported list types, preferred format first.
c.Printf("Writing manifest list to image destination\n")
var errs []string
for _, thisListType := range append([]string{selectedListType}, otherManifestMIMETypeCandidates...) {
var attemptedList internalManifest.ListPublic = updatedList
logrus.Debugf("Trying to use manifest list type %s…", thisListType)
// Perform the list conversion, if we need one.
if thisListType != updatedList.MIMEType() {
attemptedList, err = updatedList.ConvertToMIMEType(thisListType)
if err != nil {
return nil, fmt.Errorf("converting manifest list to list with MIME type %q: %w", thisListType, err)
}
}
// Check if the updates or a type conversion meaningfully changed the list of images
// by serializing them both so that we can compare them.
attemptedManifestList, err := attemptedList.Serialize()
if err != nil {
return nil, fmt.Errorf("encoding updated manifest list (%q: %#v): %w", updatedList.MIMEType(), updatedList.Instances(), err)
}
originalManifestList, err := originalList.Serialize()
if err != nil {
return nil, fmt.Errorf("encoding original manifest list for comparison (%q: %#v): %w", originalList.MIMEType(), originalList.Instances(), err)
}
// If we can't just use the original value, but we have to change it, flag an error.
if !bytes.Equal(attemptedManifestList, originalManifestList) {
if cannotModifyManifestListReason != "" {
return nil, fmt.Errorf("Manifest list must be converted to type %q to be written to destination, but we cannot modify it: %q", thisListType, cannotModifyManifestListReason)
}
logrus.Debugf("Manifest list has been updated")
} else {
// We can just use the original value, so use it instead of the one we just rebuilt, so that we don't change the digest.
attemptedManifestList = manifestList
}
// Save the manifest list.
err = c.dest.PutManifest(ctx, attemptedManifestList, nil)
if err != nil {
logrus.Debugf("Upload of manifest list type %s failed: %v", thisListType, err)
errs = append(errs, fmt.Sprintf("%s(%v)", thisListType, err))
continue
}
errs = nil
manifestList = attemptedManifestList
break
}
if errs != nil {
return nil, fmt.Errorf("Uploading manifest list failed, attempted the following formats: %s", strings.Join(errs, ", "))
}
// Sign the manifest list.
newSigs, err := c.createSignatures(ctx, manifestList, options.SignIdentity)
if err != nil {
return nil, err
}
sigs = append(sigs, newSigs...)
c.Printf("Storing list signatures\n")
if err := c.dest.PutSignaturesWithFormat(ctx, sigs, nil); err != nil {
return nil, fmt.Errorf("writing signatures: %w", err)
}
return manifestList, nil
}
|
