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forgejo/services/lfs/server.go
zeripath bbffcc3aec
Multiple Escaping Improvements (#17551)
There are multiple places where Gitea does not properly escape URLs that it is building and there are multiple places where it builds urls when there is already a simpler function available to use this.
    
This is an extensive PR attempting to fix these issues.

1. The first commit in this PR looks through all href, src and links in the Gitea codebase and has attempted to catch all the places where there is potentially incomplete escaping.
2. Whilst doing this we will prefer to use functions that create URLs over recreating them by hand.
3. All uses of strings should be directly escaped - even if they are not currently expected to contain escaping characters. The main benefit to doing this will be that we can consider relaxing the constraints on user names and reponames in future. 
4. The next commit looks at escaping in the wiki and re-considers the urls that are used there. Using the improved escaping here wiki files containing '/'. (This implementation will currently still place all of the wiki files the root directory of the repo but this would not be difficult to change.)
5. The title generation in feeds is now properly escaped.
6. EscapePound is no longer needed - urls should be PathEscaped / QueryEscaped as necessary but then re-escaped with Escape when creating html with locales Signed-off-by: Andrew Thornton <art27@cantab.net>

Signed-off-by: Andrew Thornton <art27@cantab.net>
2021-11-16 18:18:25 +00:00

566 lines
17 KiB
Go

// Copyright 2021 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package lfs
import (
"crypto/sha256"
"encoding/base64"
"encoding/hex"
"errors"
"fmt"
"io"
"net/http"
"net/url"
"path"
"regexp"
"strconv"
"strings"
"code.gitea.io/gitea/models"
"code.gitea.io/gitea/models/unit"
"code.gitea.io/gitea/modules/context"
"code.gitea.io/gitea/modules/json"
lfs_module "code.gitea.io/gitea/modules/lfs"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/storage"
"github.com/golang-jwt/jwt"
)
// requestContext contain variables from the HTTP request.
type requestContext struct {
User string
Repo string
Authorization string
}
// Claims is a JWT Token Claims
type Claims struct {
RepoID int64
Op string
UserID int64
jwt.StandardClaims
}
// DownloadLink builds a URL to download the object.
func (rc *requestContext) DownloadLink(p lfs_module.Pointer) string {
return setting.AppURL + path.Join(url.PathEscape(rc.User), url.PathEscape(rc.Repo+".git"), "info/lfs/objects", url.PathEscape(p.Oid))
}
// UploadLink builds a URL to upload the object.
func (rc *requestContext) UploadLink(p lfs_module.Pointer) string {
return setting.AppURL + path.Join(url.PathEscape(rc.User), url.PathEscape(rc.Repo+".git"), "info/lfs/objects", url.PathEscape(p.Oid), strconv.FormatInt(p.Size, 10))
}
// VerifyLink builds a URL for verifying the object.
func (rc *requestContext) VerifyLink(p lfs_module.Pointer) string {
return setting.AppURL + path.Join(url.PathEscape(rc.User), url.PathEscape(rc.Repo+".git"), "info/lfs/verify")
}
// CheckAcceptMediaType checks if the client accepts the LFS media type.
func CheckAcceptMediaType(ctx *context.Context) {
mediaParts := strings.Split(ctx.Req.Header.Get("Accept"), ";")
if mediaParts[0] != lfs_module.MediaType {
log.Trace("Calling a LFS method without accepting the correct media type: %s", lfs_module.MediaType)
writeStatus(ctx, http.StatusUnsupportedMediaType)
return
}
}
// DownloadHandler gets the content from the content store
func DownloadHandler(ctx *context.Context) {
rc := getRequestContext(ctx)
p := lfs_module.Pointer{Oid: ctx.Params("oid")}
meta := getAuthenticatedMeta(ctx, rc, p, false)
if meta == nil {
return
}
// Support resume download using Range header
var fromByte, toByte int64
toByte = meta.Size - 1
statusCode := http.StatusOK
if rangeHdr := ctx.Req.Header.Get("Range"); rangeHdr != "" {
regex := regexp.MustCompile(`bytes=(\d+)\-(\d*).*`)
match := regex.FindStringSubmatch(rangeHdr)
if len(match) > 1 {
statusCode = http.StatusPartialContent
fromByte, _ = strconv.ParseInt(match[1], 10, 32)
if fromByte >= meta.Size {
writeStatus(ctx, http.StatusRequestedRangeNotSatisfiable)
return
}
if match[2] != "" {
_toByte, _ := strconv.ParseInt(match[2], 10, 32)
if _toByte >= fromByte && _toByte < toByte {
toByte = _toByte
}
}
ctx.Resp.Header().Set("Content-Range", fmt.Sprintf("bytes %d-%d/%d", fromByte, toByte, meta.Size-fromByte))
ctx.Resp.Header().Set("Access-Control-Expose-Headers", "Content-Range")
}
}
contentStore := lfs_module.NewContentStore()
content, err := contentStore.Get(meta.Pointer)
if err != nil {
writeStatus(ctx, http.StatusNotFound)
return
}
defer content.Close()
if fromByte > 0 {
_, err = content.Seek(fromByte, io.SeekStart)
if err != nil {
log.Error("Whilst trying to read LFS OID[%s]: Unable to seek to %d Error: %v", meta.Oid, fromByte, err)
writeStatus(ctx, http.StatusInternalServerError)
return
}
}
contentLength := toByte + 1 - fromByte
ctx.Resp.Header().Set("Content-Length", strconv.FormatInt(contentLength, 10))
ctx.Resp.Header().Set("Content-Type", "application/octet-stream")
filename := ctx.Params("filename")
if len(filename) > 0 {
decodedFilename, err := base64.RawURLEncoding.DecodeString(filename)
if err == nil {
ctx.Resp.Header().Set("Content-Disposition", "attachment; filename=\""+string(decodedFilename)+"\"")
ctx.Resp.Header().Set("Access-Control-Expose-Headers", "Content-Disposition")
}
}
ctx.Resp.WriteHeader(statusCode)
if written, err := io.CopyN(ctx.Resp, content, contentLength); err != nil {
log.Error("Error whilst copying LFS OID[%s] to the response after %d bytes. Error: %v", meta.Oid, written, err)
}
}
// BatchHandler provides the batch api
func BatchHandler(ctx *context.Context) {
var br lfs_module.BatchRequest
if err := decodeJSON(ctx.Req, &br); err != nil {
log.Trace("Unable to decode BATCH request vars: Error: %v", err)
writeStatus(ctx, http.StatusBadRequest)
return
}
var isUpload bool
if br.Operation == "upload" {
isUpload = true
} else if br.Operation == "download" {
isUpload = false
} else {
log.Trace("Attempt to BATCH with invalid operation: %s", br.Operation)
writeStatus(ctx, http.StatusBadRequest)
return
}
rc := getRequestContext(ctx)
repository := getAuthenticatedRepository(ctx, rc, isUpload)
if repository == nil {
return
}
contentStore := lfs_module.NewContentStore()
var responseObjects []*lfs_module.ObjectResponse
for _, p := range br.Objects {
if !p.IsValid() {
responseObjects = append(responseObjects, buildObjectResponse(rc, p, false, false, &lfs_module.ObjectError{
Code: http.StatusUnprocessableEntity,
Message: "Oid or size are invalid",
}))
continue
}
exists, err := contentStore.Exists(p)
if err != nil {
log.Error("Unable to check if LFS OID[%s] exist. Error: %v", p.Oid, rc.User, rc.Repo, err)
writeStatus(ctx, http.StatusInternalServerError)
return
}
meta, err := repository.GetLFSMetaObjectByOid(p.Oid)
if err != nil && err != models.ErrLFSObjectNotExist {
log.Error("Unable to get LFS MetaObject [%s] for %s/%s. Error: %v", p.Oid, rc.User, rc.Repo, err)
writeStatus(ctx, http.StatusInternalServerError)
return
}
if meta != nil && p.Size != meta.Size {
responseObjects = append(responseObjects, buildObjectResponse(rc, p, false, false, &lfs_module.ObjectError{
Code: http.StatusUnprocessableEntity,
Message: fmt.Sprintf("Object %s is not %d bytes", p.Oid, p.Size),
}))
continue
}
var responseObject *lfs_module.ObjectResponse
if isUpload {
var err *lfs_module.ObjectError
if !exists && setting.LFS.MaxFileSize > 0 && p.Size > setting.LFS.MaxFileSize {
err = &lfs_module.ObjectError{
Code: http.StatusUnprocessableEntity,
Message: fmt.Sprintf("Size must be less than or equal to %d", setting.LFS.MaxFileSize),
}
}
if exists && meta == nil {
accessible, err := models.LFSObjectAccessible(ctx.User, p.Oid)
if err != nil {
log.Error("Unable to check if LFS MetaObject [%s] is accessible. Error: %v", p.Oid, err)
writeStatus(ctx, http.StatusInternalServerError)
return
}
if accessible {
_, err := models.NewLFSMetaObject(&models.LFSMetaObject{Pointer: p, RepositoryID: repository.ID})
if err != nil {
log.Error("Unable to create LFS MetaObject [%s] for %s/%s. Error: %v", p.Oid, rc.User, rc.Repo, err)
writeStatus(ctx, http.StatusInternalServerError)
return
}
} else {
exists = false
}
}
responseObject = buildObjectResponse(rc, p, false, !exists, err)
} else {
var err *lfs_module.ObjectError
if !exists || meta == nil {
err = &lfs_module.ObjectError{
Code: http.StatusNotFound,
Message: http.StatusText(http.StatusNotFound),
}
}
responseObject = buildObjectResponse(rc, p, true, false, err)
}
responseObjects = append(responseObjects, responseObject)
}
respobj := &lfs_module.BatchResponse{Objects: responseObjects}
ctx.Resp.Header().Set("Content-Type", lfs_module.MediaType)
enc := json.NewEncoder(ctx.Resp)
if err := enc.Encode(respobj); err != nil {
log.Error("Failed to encode representation as json. Error: %v", err)
}
}
// UploadHandler receives data from the client and puts it into the content store
func UploadHandler(ctx *context.Context) {
rc := getRequestContext(ctx)
p := lfs_module.Pointer{Oid: ctx.Params("oid")}
var err error
if p.Size, err = strconv.ParseInt(ctx.Params("size"), 10, 64); err != nil {
writeStatusMessage(ctx, http.StatusUnprocessableEntity, err.Error())
}
if !p.IsValid() {
log.Trace("Attempt to access invalid LFS OID[%s] in %s/%s", p.Oid, rc.User, rc.Repo)
writeStatus(ctx, http.StatusUnprocessableEntity)
return
}
repository := getAuthenticatedRepository(ctx, rc, true)
if repository == nil {
return
}
contentStore := lfs_module.NewContentStore()
exists, err := contentStore.Exists(p)
if err != nil {
log.Error("Unable to check if LFS OID[%s] exist. Error: %v", p.Oid, err)
writeStatus(ctx, http.StatusInternalServerError)
return
}
uploadOrVerify := func() error {
if exists {
accessible, err := models.LFSObjectAccessible(ctx.User, p.Oid)
if err != nil {
log.Error("Unable to check if LFS MetaObject [%s] is accessible. Error: %v", p.Oid, err)
return err
}
if !accessible {
// The file exists but the user has no access to it.
// The upload gets verified by hashing and size comparison to prove access to it.
hash := sha256.New()
written, err := io.Copy(hash, ctx.Req.Body)
if err != nil {
log.Error("Error creating hash. Error: %v", err)
return err
}
if written != p.Size {
return lfs_module.ErrSizeMismatch
}
if hex.EncodeToString(hash.Sum(nil)) != p.Oid {
return lfs_module.ErrHashMismatch
}
}
} else if err := contentStore.Put(p, ctx.Req.Body); err != nil {
log.Error("Error putting LFS MetaObject [%s] into content store. Error: %v", p.Oid, err)
return err
}
_, err := models.NewLFSMetaObject(&models.LFSMetaObject{Pointer: p, RepositoryID: repository.ID})
return err
}
defer ctx.Req.Body.Close()
if err := uploadOrVerify(); err != nil {
if errors.Is(err, lfs_module.ErrSizeMismatch) || errors.Is(err, lfs_module.ErrHashMismatch) {
log.Error("Upload does not match LFS MetaObject [%s]. Error: %v", p.Oid, err)
writeStatusMessage(ctx, http.StatusUnprocessableEntity, err.Error())
} else {
writeStatus(ctx, http.StatusInternalServerError)
}
if _, err = repository.RemoveLFSMetaObjectByOid(p.Oid); err != nil {
log.Error("Error whilst removing metaobject for LFS OID[%s]: %v", p.Oid, err)
}
return
}
writeStatus(ctx, http.StatusOK)
}
// VerifyHandler verify oid and its size from the content store
func VerifyHandler(ctx *context.Context) {
var p lfs_module.Pointer
if err := decodeJSON(ctx.Req, &p); err != nil {
writeStatus(ctx, http.StatusUnprocessableEntity)
return
}
rc := getRequestContext(ctx)
meta := getAuthenticatedMeta(ctx, rc, p, true)
if meta == nil {
return
}
contentStore := lfs_module.NewContentStore()
ok, err := contentStore.Verify(meta.Pointer)
status := http.StatusOK
if err != nil {
status = http.StatusInternalServerError
} else if !ok {
status = http.StatusNotFound
}
writeStatus(ctx, status)
}
func decodeJSON(req *http.Request, v interface{}) error {
defer req.Body.Close()
dec := json.NewDecoder(req.Body)
return dec.Decode(v)
}
func getRequestContext(ctx *context.Context) *requestContext {
return &requestContext{
User: ctx.Params("username"),
Repo: strings.TrimSuffix(ctx.Params("reponame"), ".git"),
Authorization: ctx.Req.Header.Get("Authorization"),
}
}
func getAuthenticatedMeta(ctx *context.Context, rc *requestContext, p lfs_module.Pointer, requireWrite bool) *models.LFSMetaObject {
if !p.IsValid() {
log.Info("Attempt to access invalid LFS OID[%s] in %s/%s", p.Oid, rc.User, rc.Repo)
writeStatusMessage(ctx, http.StatusUnprocessableEntity, "Oid or size are invalid")
return nil
}
repository := getAuthenticatedRepository(ctx, rc, requireWrite)
if repository == nil {
return nil
}
meta, err := repository.GetLFSMetaObjectByOid(p.Oid)
if err != nil {
log.Error("Unable to get LFS OID[%s] Error: %v", p.Oid, err)
writeStatus(ctx, http.StatusNotFound)
return nil
}
return meta
}
func getAuthenticatedRepository(ctx *context.Context, rc *requestContext, requireWrite bool) *models.Repository {
repository, err := models.GetRepositoryByOwnerAndName(rc.User, rc.Repo)
if err != nil {
log.Error("Unable to get repository: %s/%s Error: %v", rc.User, rc.Repo, err)
writeStatus(ctx, http.StatusNotFound)
return nil
}
if !authenticate(ctx, repository, rc.Authorization, false, requireWrite) {
requireAuth(ctx)
return nil
}
return repository
}
func buildObjectResponse(rc *requestContext, pointer lfs_module.Pointer, download, upload bool, err *lfs_module.ObjectError) *lfs_module.ObjectResponse {
rep := &lfs_module.ObjectResponse{Pointer: pointer}
if err != nil {
rep.Error = err
} else {
rep.Actions = make(map[string]*lfs_module.Link)
header := make(map[string]string)
if len(rc.Authorization) > 0 {
header["Authorization"] = rc.Authorization
}
if download {
rep.Actions["download"] = &lfs_module.Link{Href: rc.DownloadLink(pointer), Header: header}
if setting.LFS.ServeDirect {
//If we have a signed url (S3, object storage), redirect to this directly.
u, err := storage.LFS.URL(pointer.RelativePath(), pointer.Oid)
if u != nil && err == nil {
rep.Actions["download"] = &lfs_module.Link{Href: u.String(), Header: header}
}
}
}
if upload {
rep.Actions["upload"] = &lfs_module.Link{Href: rc.UploadLink(pointer), Header: header}
verifyHeader := make(map[string]string)
for key, value := range header {
verifyHeader[key] = value
}
// This is only needed to workaround https://github.com/git-lfs/git-lfs/issues/3662
verifyHeader["Accept"] = lfs_module.MediaType
rep.Actions["verify"] = &lfs_module.Link{Href: rc.VerifyLink(pointer), Header: verifyHeader}
}
}
return rep
}
func writeStatus(ctx *context.Context, status int) {
writeStatusMessage(ctx, status, http.StatusText(status))
}
func writeStatusMessage(ctx *context.Context, status int, message string) {
ctx.Resp.Header().Set("Content-Type", lfs_module.MediaType)
ctx.Resp.WriteHeader(status)
er := lfs_module.ErrorResponse{Message: message}
enc := json.NewEncoder(ctx.Resp)
if err := enc.Encode(er); err != nil {
log.Error("Failed to encode error response as json. Error: %v", err)
}
}
// authenticate uses the authorization string to determine whether
// or not to proceed. This server assumes an HTTP Basic auth format.
func authenticate(ctx *context.Context, repository *models.Repository, authorization string, requireSigned, requireWrite bool) bool {
accessMode := models.AccessModeRead
if requireWrite {
accessMode = models.AccessModeWrite
}
// ctx.IsSigned is unnecessary here, this will be checked in perm.CanAccess
perm, err := models.GetUserRepoPermission(repository, ctx.User)
if err != nil {
log.Error("Unable to GetUserRepoPermission for user %-v in repo %-v Error: %v", ctx.User, repository)
return false
}
canRead := perm.CanAccess(accessMode, unit.TypeCode)
if canRead && (!requireSigned || ctx.IsSigned) {
return true
}
user, err := parseToken(authorization, repository, accessMode)
if err != nil {
// Most of these are Warn level - the true internal server errors are logged in parseToken already
log.Warn("Authentication failure for provided token with Error: %v", err)
return false
}
ctx.User = user
return true
}
func handleLFSToken(tokenSHA string, target *models.Repository, mode models.AccessMode) (*models.User, error) {
if !strings.Contains(tokenSHA, ".") {
return nil, nil
}
token, err := jwt.ParseWithClaims(tokenSHA, &Claims{}, func(t *jwt.Token) (interface{}, error) {
if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
return nil, fmt.Errorf("unexpected signing method: %v", t.Header["alg"])
}
return setting.LFS.JWTSecretBytes, nil
})
if err != nil {
return nil, nil
}
claims, claimsOk := token.Claims.(*Claims)
if !token.Valid || !claimsOk {
return nil, fmt.Errorf("invalid token claim")
}
if claims.RepoID != target.ID {
return nil, fmt.Errorf("invalid token claim")
}
if mode == models.AccessModeWrite && claims.Op != "upload" {
return nil, fmt.Errorf("invalid token claim")
}
u, err := models.GetUserByID(claims.UserID)
if err != nil {
log.Error("Unable to GetUserById[%d]: Error: %v", claims.UserID, err)
return nil, err
}
return u, nil
}
func parseToken(authorization string, target *models.Repository, mode models.AccessMode) (*models.User, error) {
if authorization == "" {
return nil, fmt.Errorf("no token")
}
parts := strings.SplitN(authorization, " ", 2)
if len(parts) != 2 {
return nil, fmt.Errorf("no token")
}
tokenSHA := parts[1]
switch strings.ToLower(parts[0]) {
case "bearer":
fallthrough
case "token":
return handleLFSToken(tokenSHA, target, mode)
}
return nil, fmt.Errorf("token not found")
}
func requireAuth(ctx *context.Context) {
ctx.Resp.Header().Set("WWW-Authenticate", "Basic realm=gitea-lfs")
writeStatus(ctx, http.StatusUnauthorized)
}