dotcloud/docker

package registry // import "github.com/docker/docker/registry"

import (
    // this is required for some certificates
    "context"
    _ "crypto/sha512"
    "encoding/json"
    "fmt"
    "net/http"
    "net/http/cookiejar"
    "net/url"
    "strings"
    "sync"

    "github.com/containerd/log"
    "github.com/docker/docker/api/types/registry"
    "github.com/docker/docker/errdefs"
    "github.com/docker/docker/pkg/ioutils"
    "github.com/pkg/errors"
)

// A session is used to communicate with a V1 registry
type session struct {
    indexEndpoint *v1Endpoint
    client        *http.Client
}

type authTransport struct {
    http.RoundTripper
    *registry.AuthConfig

    alwaysSetBasicAuth bool
    token              []string

    mu     sync.Mutex                      // guards modReq
    modReq map[*http.Request]*http.Request // original -> modified
}

// newAuthTransport handles the auth layer when communicating with a v1 registry (private or official)
//
// For private v1 registries, set alwaysSetBasicAuth to true.
//
// For the official v1 registry, if there isn't already an Authorization header in the request,
// but there is an X-Docker-Token header set to true, then Basic Auth will be used to set the Authorization header.
// After sending the request with the provided base http.RoundTripper, if an X-Docker-Token header, representing
// a token, is present in the response, then it gets cached and sent in the Authorization header of all subsequent
// requests.
//
// If the server sends a token without the client having requested it, it is ignored.
//
// This RoundTripper also has a CancelRequest method important for correct timeout handling.
func newAuthTransport(base http.RoundTripper, authConfig *registry.AuthConfig, alwaysSetBasicAuth bool) *authTransport {
    if base == nil {
        base = http.DefaultTransport
    }
    return &authTransport{
        RoundTripper:       base,
        AuthConfig:         authConfig,
        alwaysSetBasicAuth: alwaysSetBasicAuth,
        modReq:             make(map[*http.Request]*http.Request),
    }
}

// cloneRequest returns a clone of the provided *http.Request.
// The clone is a shallow copy of the struct and its Header map.
func cloneRequest(r *http.Request) *http.Request {
    // shallow copy of the struct
    r2 := new(http.Request)
    *r2 = *r
    // deep copy of the Header
    r2.Header = make(http.Header, len(r.Header))
    for k, s := range r.Header {
        r2.Header[k] = append([]string(nil), s...)
    }

    return r2
}

// RoundTrip changes an HTTP request's headers to add the necessary
// authentication-related headers
func (tr *authTransport) RoundTrip(orig *http.Request) (*http.Response, error) {
    // Authorization should not be set on 302 redirect for untrusted locations.
    // This logic mirrors the behavior in addRequiredHeadersToRedirectedRequests.
    // As the authorization logic is currently implemented in RoundTrip,
    // a 302 redirect is detected by looking at the Referrer header as go http package adds said header.
    // This is safe as Docker doesn't set Referrer in other scenarios.
    if orig.Header.Get("Referer") != "" && !trustedLocation(orig) {
        return tr.RoundTripper.RoundTrip(orig)
    }

    req := cloneRequest(orig)
    tr.mu.Lock()
    tr.modReq[orig] = req
    tr.mu.Unlock()

    if tr.alwaysSetBasicAuth {
        if tr.AuthConfig == nil {
            return nil, errors.New("unexpected error: empty auth config")
        }
        req.SetBasicAuth(tr.Username, tr.Password)
        return tr.RoundTripper.RoundTrip(req)
    }

    // Don't override
    if req.Header.Get("Authorization") == "" {
        if req.Header.Get("X-Docker-Token") == "true" && tr.AuthConfig != nil && len(tr.Username) > 0 {
            req.SetBasicAuth(tr.Username, tr.Password)
        } else if len(tr.token) > 0 {
            req.Header.Set("Authorization", "Token "+strings.Join(tr.token, ","))
        }
    }
    resp, err := tr.RoundTripper.RoundTrip(req)
    if err != nil {
        tr.mu.Lock()
        delete(tr.modReq, orig)
        tr.mu.Unlock()
        return nil, err
    }
    if len(resp.Header["X-Docker-Token"]) > 0 {
        tr.token = resp.Header["X-Docker-Token"]
    }
    resp.Body = &ioutils.OnEOFReader{
        Rc: resp.Body,
        Fn: func() {
            tr.mu.Lock()
            delete(tr.modReq, orig)
            tr.mu.Unlock()
        },
    }
    return resp, nil
}

// CancelRequest cancels an in-flight request by closing its connection.
func (tr *authTransport) CancelRequest(req *http.Request) {
    type canceler interface {
        CancelRequest(*http.Request)
    }
    if cr, ok := tr.RoundTripper.(canceler); ok {
        tr.mu.Lock()
        modReq := tr.modReq[req]
        delete(tr.modReq, req)
        tr.mu.Unlock()
        cr.CancelRequest(modReq)
    }
}

func authorizeClient(client *http.Client, authConfig *registry.AuthConfig, endpoint *v1Endpoint) error {
    var alwaysSetBasicAuth bool

    // If we're working with a standalone private registry over HTTPS, send Basic Auth headers
    // alongside all our requests.
    if endpoint.String() != IndexServer && endpoint.URL.Scheme == "https" {
        info, err := endpoint.ping()
        if err != nil {
            return err
        }
        if info.Standalone && authConfig != nil {
            log.G(context.TODO()).Debugf("Endpoint %s is eligible for private registry. Enabling decorator.", endpoint.String())
            alwaysSetBasicAuth = true
        }
    }

    // Annotate the transport unconditionally so that v2 can
    // properly fallback on v1 when an image is not found.
    client.Transport = newAuthTransport(client.Transport, authConfig, alwaysSetBasicAuth)

    jar, err := cookiejar.New(nil)
    if err != nil {
        return errdefs.System(errors.New("cookiejar.New is not supposed to return an error"))
    }
    client.Jar = jar

    return nil
}

func newSession(client *http.Client, endpoint *v1Endpoint) *session {
    return &session{
        client:        client,
        indexEndpoint: endpoint,
    }
}

// defaultSearchLimit is the default value for maximum number of returned search results.
const defaultSearchLimit = 25

// searchRepositories performs a search against the remote repository
func (r *session) searchRepositories(term string, limit int) (*registry.SearchResults, error) {
    if limit == 0 {
        limit = defaultSearchLimit
    }
    if limit < 1 || limit > 100 {
        return nil, invalidParamf("limit %d is outside the range of [1, 100]", limit)
    }
    u := r.indexEndpoint.String() + "search?q=" + url.QueryEscape(term) + "&n=" + url.QueryEscape(fmt.Sprintf("%d", limit))
    log.G(context.TODO()).WithField("url", u).Debug("searchRepositories")

    req, err := http.NewRequest(http.MethodGet, u, nil)
    if err != nil {
        return nil, invalidParamWrapf(err, "error building request")
    }
    // Have the AuthTransport send authentication, when logged in.
    req.Header.Set("X-Docker-Token", "true")
    res, err := r.client.Do(req)
    if err != nil {
        return nil, errdefs.System(err)
    }
    defer res.Body.Close()
    if res.StatusCode != http.StatusOK {
        // TODO(thaJeztah): return upstream response body for errors (see https://github.com/moby/moby/issues/27286).
        return nil, errdefs.Unknown(fmt.Errorf("Unexpected status code %d", res.StatusCode))
    }
    result := &registry.SearchResults{}
    err = json.NewDecoder(res.Body).Decode(result)
    if err != nil {
        return nil, errdefs.System(errors.Wrap(err, "error decoding registry search results"))
    }
    return result, nil
}