distribution/registry/handlers/manifests.go
Jaime Martinez 2763ba1eae
Do not write manifests on HEAD requests
Signed-off-by: Jaime Martinez <jmartinez@gitlab.com>
2024-02-29 11:16:11 +11:00

492 lines
15 KiB
Go

package handlers
import (
"bytes"
"fmt"
"mime"
"net/http"
"strings"
"github.com/distribution/distribution/v3"
"github.com/distribution/distribution/v3/internal/dcontext"
"github.com/distribution/distribution/v3/manifest/manifestlist"
"github.com/distribution/distribution/v3/manifest/ocischema"
"github.com/distribution/distribution/v3/manifest/schema2"
"github.com/distribution/distribution/v3/registry/api/errcode"
"github.com/distribution/distribution/v3/registry/storage/driver"
"github.com/distribution/reference"
"github.com/gorilla/handlers"
"github.com/opencontainers/go-digest"
v1 "github.com/opencontainers/image-spec/specs-go/v1"
)
const (
defaultArch = "amd64"
defaultOS = "linux"
maxManifestBodySize = 4 * 1024 * 1024
imageClass = "image"
)
type storageType int
const (
manifestSchema2 storageType = iota // 0
manifestlistSchema // 1
ociSchema // 2
ociImageIndexSchema // 3
numStorageTypes // 4
)
// manifestDispatcher takes the request context and builds the
// appropriate handler for handling manifest requests.
func manifestDispatcher(ctx *Context, r *http.Request) http.Handler {
manifestHandler := &manifestHandler{
Context: ctx,
}
ref := getReference(ctx)
dgst, err := digest.Parse(ref)
if err != nil {
// We just have a tag
manifestHandler.Tag = ref
} else {
manifestHandler.Digest = dgst
}
mhandler := handlers.MethodHandler{
http.MethodGet: http.HandlerFunc(manifestHandler.GetManifest),
http.MethodHead: http.HandlerFunc(manifestHandler.GetManifest),
}
if !ctx.readOnly {
mhandler[http.MethodPut] = http.HandlerFunc(manifestHandler.PutManifest)
mhandler[http.MethodDelete] = http.HandlerFunc(manifestHandler.DeleteManifest)
}
return mhandler
}
// manifestHandler handles http operations on image manifests.
type manifestHandler struct {
*Context
// One of tag or digest gets set, depending on what is present in context.
Tag string
Digest digest.Digest
}
// GetManifest fetches the image manifest from the storage backend, if it exists.
func (imh *manifestHandler) GetManifest(w http.ResponseWriter, r *http.Request) {
dcontext.GetLogger(imh).Debug("GetImageManifest")
manifests, err := imh.Repository.Manifests(imh)
if err != nil {
imh.Errors = append(imh.Errors, err)
return
}
var supports [numStorageTypes]bool
// this parsing of Accept headers is not quite as full-featured as godoc.org's parser, but we don't care about "q=" values
// https://github.com/golang/gddo/blob/e91d4165076d7474d20abda83f92d15c7ebc3e81/httputil/header/header.go#L165-L202
for _, acceptHeader := range r.Header["Accept"] {
// r.Header[...] is a slice in case the request contains the same header more than once
// if the header isn't set, we'll get the zero value, which "range" will handle gracefully
// we need to split each header value on "," to get the full list of "Accept" values (per RFC 2616)
// https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.1
for _, mediaType := range strings.Split(acceptHeader, ",") {
if mediaType, _, err = mime.ParseMediaType(mediaType); err != nil {
continue
}
if mediaType == schema2.MediaTypeManifest {
supports[manifestSchema2] = true
}
if mediaType == manifestlist.MediaTypeManifestList {
supports[manifestlistSchema] = true
}
if mediaType == v1.MediaTypeImageManifest {
supports[ociSchema] = true
}
if mediaType == v1.MediaTypeImageIndex {
supports[ociImageIndexSchema] = true
}
}
}
if imh.Tag != "" {
tags := imh.Repository.Tags(imh)
desc, err := tags.Get(imh, imh.Tag)
if err != nil {
if _, ok := err.(distribution.ErrTagUnknown); ok {
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestUnknown.WithDetail(err))
} else {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
}
return
}
imh.Digest = desc.Digest
}
if etagMatch(r, imh.Digest.String()) {
w.WriteHeader(http.StatusNotModified)
return
}
var options []distribution.ManifestServiceOption
if imh.Tag != "" {
options = append(options, distribution.WithTag(imh.Tag))
}
manifest, err := manifests.Get(imh, imh.Digest, options...)
if err != nil {
if _, ok := err.(distribution.ErrManifestUnknownRevision); ok {
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestUnknown.WithDetail(err))
} else {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
}
return
}
// determine the type of the returned manifest
manifestType := manifestSchema2
manifestList, isManifestList := manifest.(*manifestlist.DeserializedManifestList)
if _, isOCImanifest := manifest.(*ocischema.DeserializedManifest); isOCImanifest {
manifestType = ociSchema
} else if isManifestList {
if manifestList.MediaType == manifestlist.MediaTypeManifestList {
manifestType = manifestlistSchema
} else if manifestList.MediaType == v1.MediaTypeImageIndex {
manifestType = ociImageIndexSchema
}
}
if manifestType == ociSchema && !supports[ociSchema] {
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestUnknown.WithMessage("OCI manifest found, but accept header does not support OCI manifests"))
return
}
if manifestType == ociImageIndexSchema && !supports[ociImageIndexSchema] {
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestUnknown.WithMessage("OCI index found, but accept header does not support OCI indexes"))
return
}
if imh.Tag != "" && manifestType == manifestlistSchema && !supports[manifestlistSchema] {
// Rewrite manifest in schema1 format
dcontext.GetLogger(imh).Infof("rewriting manifest list %s in schema1 format to support old client", imh.Digest.String())
// Find the image manifest corresponding to the default
// platform
var manifestDigest digest.Digest
for _, manifestDescriptor := range manifestList.Manifests {
if manifestDescriptor.Platform.Architecture == defaultArch && manifestDescriptor.Platform.OS == defaultOS {
manifestDigest = manifestDescriptor.Digest
break
}
}
if manifestDigest == "" {
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestUnknown)
return
}
manifest, err = manifests.Get(imh, manifestDigest)
if err != nil {
if _, ok := err.(distribution.ErrManifestUnknownRevision); ok {
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestUnknown.WithDetail(err))
} else {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
}
return
}
if _, isSchema2 := manifest.(*schema2.DeserializedManifest); isSchema2 && !supports[manifestSchema2] {
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestInvalid.WithMessage("Schema 2 manifest not supported by client"))
return
} else {
imh.Digest = manifestDigest
}
}
ct, p, err := manifest.Payload()
if err != nil {
return
}
w.Header().Set("Content-Type", ct)
w.Header().Set("Content-Length", fmt.Sprint(len(p)))
w.Header().Set("Docker-Content-Digest", imh.Digest.String())
w.Header().Set("Etag", fmt.Sprintf(`"%s"`, imh.Digest))
if r.Method == http.MethodHead {
return
}
if _, err := w.Write(p); err != nil {
w.WriteHeader(http.StatusInternalServerError)
}
}
func etagMatch(r *http.Request, etag string) bool {
for _, headerVal := range r.Header["If-None-Match"] {
if headerVal == etag || headerVal == fmt.Sprintf(`"%s"`, etag) { // allow quoted or unquoted
return true
}
}
return false
}
// PutManifest validates and stores a manifest in the registry.
func (imh *manifestHandler) PutManifest(w http.ResponseWriter, r *http.Request) {
dcontext.GetLogger(imh).Debug("PutImageManifest")
manifests, err := imh.Repository.Manifests(imh)
if err != nil {
imh.Errors = append(imh.Errors, err)
return
}
var jsonBuf bytes.Buffer
if err := copyFullPayload(imh, w, r, &jsonBuf, maxManifestBodySize, "image manifest PUT"); err != nil {
// copyFullPayload reports the error if necessary
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestInvalid.WithDetail(err.Error()))
return
}
mediaType := r.Header.Get("Content-Type")
manifest, desc, err := distribution.UnmarshalManifest(mediaType, jsonBuf.Bytes())
if err != nil {
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestInvalid.WithDetail(err))
return
}
if imh.Digest != "" {
if desc.Digest != imh.Digest {
dcontext.GetLogger(imh).Errorf("payload digest does not match: %q != %q", desc.Digest, imh.Digest)
imh.Errors = append(imh.Errors, errcode.ErrorCodeDigestInvalid)
return
}
} else if imh.Tag != "" {
imh.Digest = desc.Digest
} else {
imh.Errors = append(imh.Errors, errcode.ErrorCodeTagInvalid.WithDetail("no tag or digest specified"))
return
}
isAnOCIManifest := mediaType == v1.MediaTypeImageManifest || mediaType == v1.MediaTypeImageIndex
if isAnOCIManifest {
dcontext.GetLogger(imh).Debug("Putting an OCI Manifest!")
} else {
dcontext.GetLogger(imh).Debug("Putting a Docker Manifest!")
}
var options []distribution.ManifestServiceOption
if imh.Tag != "" {
options = append(options, distribution.WithTag(imh.Tag))
}
if err := imh.applyResourcePolicy(manifest); err != nil {
imh.Errors = append(imh.Errors, err)
return
}
_, err = manifests.Put(imh, manifest, options...)
if err != nil {
// TODO(stevvooe): These error handling switches really need to be
// handled by an app global mapper.
if err == distribution.ErrUnsupported {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnsupported)
return
}
if err == distribution.ErrAccessDenied {
imh.Errors = append(imh.Errors, errcode.ErrorCodeDenied)
return
}
switch err := err.(type) {
case distribution.ErrManifestVerification:
for _, verificationError := range err {
switch verificationError := verificationError.(type) {
case distribution.ErrManifestBlobUnknown:
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestBlobUnknown.WithDetail(verificationError.Digest))
case distribution.ErrManifestNameInvalid:
imh.Errors = append(imh.Errors, errcode.ErrorCodeNameInvalid.WithDetail(err))
case distribution.ErrManifestUnverified:
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestUnverified)
default:
if verificationError == digest.ErrDigestInvalidFormat {
imh.Errors = append(imh.Errors, errcode.ErrorCodeDigestInvalid)
} else {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown, verificationError)
}
}
}
case errcode.Error:
imh.Errors = append(imh.Errors, err)
default:
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
}
return
}
// Tag this manifest
if imh.Tag != "" {
tags := imh.Repository.Tags(imh)
err = tags.Tag(imh, imh.Tag, desc)
if err != nil {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
return
}
}
// Construct a canonical url for the uploaded manifest.
ref, err := reference.WithDigest(imh.Repository.Named(), imh.Digest)
if err != nil {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
return
}
location, err := imh.urlBuilder.BuildManifestURL(ref)
if err != nil {
// NOTE(stevvooe): Given the behavior above, this absurdly unlikely to
// happen. We'll log the error here but proceed as if it worked. Worst
// case, we set an empty location header.
dcontext.GetLogger(imh).Errorf("error building manifest url from digest: %v", err)
}
w.Header().Set("Location", location)
w.Header().Set("Docker-Content-Digest", imh.Digest.String())
w.WriteHeader(http.StatusCreated)
dcontext.GetLogger(imh).Debug("Succeeded in putting manifest!")
}
// applyResourcePolicy checks whether the resource class matches what has
// been authorized and allowed by the policy configuration.
func (imh *manifestHandler) applyResourcePolicy(manifest distribution.Manifest) error {
allowedClasses := imh.App.Config.Policy.Repository.Classes
if len(allowedClasses) == 0 {
return nil
}
var class string
switch m := manifest.(type) {
case *schema2.DeserializedManifest:
switch m.Config.MediaType {
case schema2.MediaTypeImageConfig:
class = imageClass
case schema2.MediaTypePluginConfig:
class = "plugin"
default:
return errcode.ErrorCodeDenied.WithMessage("unknown manifest class for " + m.Config.MediaType)
}
case *ocischema.DeserializedManifest:
switch m.Config.MediaType {
case v1.MediaTypeImageConfig:
class = imageClass
default:
return errcode.ErrorCodeDenied.WithMessage("unknown manifest class for " + m.Config.MediaType)
}
}
if class == "" {
return nil
}
// Check to see if class is allowed in registry
var allowedClass bool
for _, c := range allowedClasses {
if class == c {
allowedClass = true
break
}
}
if !allowedClass {
return errcode.ErrorCodeDenied.WithMessage(fmt.Sprintf("registry does not allow %s manifest", class))
}
resources := authorizedResources(imh)
n := imh.Repository.Named().Name()
var foundResource bool
for _, r := range resources {
if r.Name == n {
if r.Class == "" {
r.Class = imageClass
}
if r.Class == class {
return nil
}
foundResource = true
}
}
// resource was found but no matching class was found
if foundResource {
return errcode.ErrorCodeDenied.WithMessage(fmt.Sprintf("repository not authorized for %s manifest", class))
}
return nil
}
// DeleteManifest removes the manifest with the given digest or the tag with the given name from the registry.
func (imh *manifestHandler) DeleteManifest(w http.ResponseWriter, r *http.Request) {
dcontext.GetLogger(imh).Debug("DeleteImageManifest")
if imh.App.isCache {
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnsupported)
return
}
if imh.Tag != "" {
dcontext.GetLogger(imh).Debug("DeleteImageTag")
tagService := imh.Repository.Tags(imh.Context)
if err := tagService.Untag(imh.Context, imh.Tag); err != nil {
switch err.(type) {
case distribution.ErrTagUnknown, driver.PathNotFoundError:
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestUnknown.WithDetail(err))
default:
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown.WithDetail(err))
}
return
}
w.WriteHeader(http.StatusAccepted)
return
}
manifests, err := imh.Repository.Manifests(imh)
if err != nil {
imh.Errors = append(imh.Errors, err)
return
}
err = manifests.Delete(imh, imh.Digest)
if err != nil {
switch err {
case digest.ErrDigestUnsupported:
case digest.ErrDigestInvalidFormat:
imh.Errors = append(imh.Errors, errcode.ErrorCodeDigestInvalid)
return
case distribution.ErrBlobUnknown:
imh.Errors = append(imh.Errors, errcode.ErrorCodeManifestUnknown)
return
case distribution.ErrUnsupported:
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnsupported)
return
default:
imh.Errors = append(imh.Errors, errcode.ErrorCodeUnknown)
return
}
}
tagService := imh.Repository.Tags(imh)
referencedTags, err := tagService.Lookup(imh, distribution.Descriptor{Digest: imh.Digest})
if err != nil {
imh.Errors = append(imh.Errors, err)
return
}
for _, tag := range referencedTags {
if err := tagService.Untag(imh, tag); err != nil {
imh.Errors = append(imh.Errors, err)
return
}
}
w.WriteHeader(http.StatusAccepted)
}