Files
opencloud/services/collaboration/pkg/middleware/wopicontext.go
2024-10-24 09:56:54 +02:00

265 lines
9.0 KiB
Go

package middleware
import (
"context"
"crypto/md5"
"encoding/hex"
"errors"
"fmt"
"net/http"
"strconv"
"strings"
"time"
appproviderv1beta1 "github.com/cs3org/go-cs3apis/cs3/app/provider/v1beta1"
providerv1beta1 "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
ctxpkg "github.com/cs3org/reva/v2/pkg/ctx"
rjwt "github.com/cs3org/reva/v2/pkg/token/manager/jwt"
"github.com/golang-jwt/jwt/v5"
"github.com/owncloud/ocis/v2/services/collaboration/pkg/config"
"github.com/owncloud/ocis/v2/services/collaboration/pkg/helpers"
"github.com/rs/zerolog"
microstore "go-micro.dev/v4/store"
"google.golang.org/grpc/metadata"
)
type key int
const (
wopiContextKey key = iota
)
// WopiContext wraps all the information we need for WOPI
type WopiContext struct {
AccessToken string
ViewOnlyToken string
FileReference *providerv1beta1.Reference
TemplateReference *providerv1beta1.Reference
ViewMode appproviderv1beta1.ViewMode
}
// WopiContextAuthMiddleware will prepare an HTTP handler to be used as
// middleware. The handler will create a WopiContext by parsing the
// access_token (which must be provided as part of the URL query).
// The access_token is required.
//
// This middleware will add the following to the request's context:
// * The access token as metadata for outgoing requests (for the
// authentication against the CS3 API, the "x-access-token" header).
// * The created WopiContext for the request
// * A contextual zerologger containing information about the request
// and the WopiContext
func WopiContextAuthMiddleware(cfg *config.Config, st microstore.Store, next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
// include additional info in the context's logger
// we might need to check https://learn.microsoft.com/en-us/microsoft-365/cloud-storage-partner-program/rest/common-headers
// although some headers might not be sent depending on the client.
logger := zerolog.Ctx(ctx)
wopiLogger := logger.With().
Str("WopiSessionId", r.Header.Get("X-WOPI-SessionId")).
Str("WopiOverride", r.Header.Get("X-WOPI-Override")).
Str("WopiProof", r.Header.Get("X-WOPI-Proof")).
Str("WopiProofOld", r.Header.Get("X-WOPI-ProofOld")).
Str("WopiStamp", r.Header.Get("X-WOPI-TimeStamp")).
Logger()
accessToken := r.URL.Query().Get("access_token")
if accessToken == "" {
wopiLogger.Error().Msg("missing access token")
http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
return
}
if cfg.Wopi.ShortTokens {
records, err := st.Read(accessToken)
if err != nil {
wopiLogger.Error().Err(err).Msg("cannot retrieve access token from store")
http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
return
}
if len(records) != 1 {
wopiLogger.Error().Int("records", len(records)).Msg("no record found for the token")
http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
return
}
accessToken = string(records[0].Value)
}
claims := &Claims{}
_, err := jwt.ParseWithClaims(accessToken, claims, func(token *jwt.Token) (interface{}, error) {
if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
}
return []byte(cfg.Wopi.Secret), nil
})
if err != nil {
wopiLogger.Error().Err(err).Msg("failed to parse jwt token")
http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
return
}
wopiContextAccessToken, err := DecryptAES([]byte(cfg.Wopi.Secret), claims.WopiContext.AccessToken)
if err != nil {
wopiLogger.Error().Err(err).Msg("failed to decrypt reva access token")
http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
return
}
tokenManager, err := rjwt.New(map[string]interface{}{
"secret": cfg.TokenManager.JWTSecret,
"expires": int64(24 * 60 * 60),
})
if err != nil {
wopiLogger.Error().Err(err).Msg("failed to get a reva token manager")
http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
return
}
user, _, err := tokenManager.DismantleToken(ctx, wopiContextAccessToken)
if err != nil {
wopiLogger.Error().Err(err).Msg("failed to dismantle reva token manager")
http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
return
}
claims.WopiContext.AccessToken = wopiContextAccessToken
ctx = context.WithValue(ctx, wopiContextKey, claims.WopiContext)
// authentication for the CS3 api
ctx = metadata.AppendToOutgoingContext(ctx, ctxpkg.TokenHeader, claims.WopiContext.AccessToken)
ctx = ctxpkg.ContextSetUser(ctx, user)
// include additional info in the context's logger
wopiLogger = wopiLogger.With().
Str("FileReference", claims.WopiContext.FileReference.String()).
Str("ViewMode", claims.WopiContext.ViewMode.String()).
Str("Requester", user.GetId().String()).
Logger()
ctx = wopiLogger.WithContext(ctx)
hashedRef := helpers.HashResourceId(claims.WopiContext.FileReference.GetResourceId())
fileID := parseWopiFileID(cfg, r.URL.Path)
if claims.WopiContext.TemplateReference != nil {
hashedTemplateRef := helpers.HashResourceId(claims.WopiContext.TemplateReference.GetResourceId())
// the fileID could be one of the references within the access token if both are set
// because we can use the access token to get the contents of the template file
if fileID != hashedTemplateRef && fileID != hashedRef {
wopiLogger.Error().Msg("file reference in the URL doesn't match the one inside the access token")
http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
return
}
} else {
if fileID != hashedRef {
wopiLogger.Error().Msg("file reference in the URL doesn't match the one inside the access token")
http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
return
}
}
next.ServeHTTP(w, r.WithContext(ctx))
})
}
// Extract a WopiContext from the context if possible. An error will be
// returned if there is no WopiContext
func WopiContextFromCtx(ctx context.Context) (WopiContext, error) {
if wopiContext, ok := ctx.Value(wopiContextKey).(WopiContext); ok {
return wopiContext, nil
}
return WopiContext{}, errors.New("no wopi context found")
}
// Set a WopiContext in the context. A new context will be returned with the
// add WopiContext inside. Note that the old one won't have the WopiContext set.
//
// This method is used for testing. The WopiContextAuthMiddleware should be
// used instead in order to provide a valid WopiContext
func WopiContextToCtx(ctx context.Context, wopiContext WopiContext) context.Context {
return context.WithValue(ctx, wopiContextKey, wopiContext)
}
// The access token inside the wopiContext is expected to be decrypted.
// In order to generate the access token for WOPI, the reva token inside the
// wopiContext will be encrypted
func GenerateWopiToken(wopiContext WopiContext, cfg *config.Config, st microstore.Store) (string, int64, error) {
if cfg.Wopi.ShortTokens && st == nil {
return "", 0, errors.New("Cannot generate a short token without microstore")
}
cryptedReqAccessToken, err := EncryptAES([]byte(cfg.Wopi.Secret), wopiContext.AccessToken)
if err != nil {
return "", 0, err
}
cs3Claims := &jwt.RegisteredClaims{}
cs3JWTparser := jwt.Parser{}
_, _, err = cs3JWTparser.ParseUnverified(wopiContext.AccessToken, cs3Claims)
if err != nil {
return "", 0, err
}
wopiContext.AccessToken = cryptedReqAccessToken
claims := &Claims{
WopiContext: wopiContext,
RegisteredClaims: jwt.RegisteredClaims{
ExpiresAt: cs3Claims.ExpiresAt,
},
}
token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
accessToken, err := token.SignedString([]byte(cfg.Wopi.Secret))
if cfg.Wopi.ShortTokens {
c := md5.New()
c.Write([]byte(accessToken))
shortAccessToken := hex.EncodeToString(c.Sum(nil)) + strconv.FormatInt(time.Now().UnixNano(), 16)
errWrite := st.Write(&microstore.Record{
Key: shortAccessToken,
Value: []byte(accessToken),
Expiry: time.Until(claims.ExpiresAt.Time),
})
return shortAccessToken, claims.ExpiresAt.UnixMilli(), errWrite
}
return accessToken, claims.ExpiresAt.UnixMilli(), err
}
// parseWopiFileID extracts the file id from a wopi path
//
// If the file id is a jwt, it will be decoded and the file id will be extracted from the jwt claims.
// If the file id is not a jwt, it will be returned as is.
func parseWopiFileID(cfg *config.Config, path string) string {
s := strings.Split(path, "/")
if len(s) < 4 || (s[1] != "wopi" && s[2] != "files") {
return path
}
// check if the fileid is a jwt
if strings.Contains(s[3], ".") {
token, err := jwt.Parse(s[3], func(_ *jwt.Token) (interface{}, error) {
return []byte(cfg.Wopi.ProxySecret), nil
})
if err != nil {
return s[3]
}
claims, ok := token.Claims.(jwt.MapClaims)
if !ok {
return s[3]
}
f, ok := claims["f"].(string)
if !ok {
return s[3]
}
return f
}
// fileid is not a jwt
return s[3]
}