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gitea/services/lfs/server.go

570 lines
17 KiB

// 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"
git_model "code.gitea.io/gitea/models/git"
"code.gitea.io/gitea/models/perm"
access_model "code.gitea.io/gitea/models/perm/access"
repo_model "code.gitea.io/gitea/models/repo"
"code.gitea.io/gitea/models/unit"
user_model "code.gitea.io/gitea/models/user"
"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/v4"
)
// 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.RegisteredClaims
}
// 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 := git_model.GetLFSMetaObjectByOid(repository.ID, p.Oid)
if err != nil && err != git_model.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 := git_model.LFSObjectAccessible(ctx.Doer, 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 := git_model.NewLFSMetaObject(&git_model.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 := git_model.LFSObjectAccessible(ctx.Doer, 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 := git_model.NewLFSMetaObject(&git_model.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 = git_model.RemoveLFSMetaObjectByOid(repository.ID, 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) *git_model.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 := git_model.GetLFSMetaObjectByOid(repository.ID, 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) *repo_model.Repository {
repository, err := repo_model.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 *repo_model.Repository, authorization string, requireSigned, requireWrite bool) bool {
accessMode := perm.AccessModeRead
if requireWrite {
accessMode = perm.AccessModeWrite
}
// ctx.IsSigned is unnecessary here, this will be checked in perm.CanAccess
perm, err := access_model.GetUserRepoPermission(ctx, repository, ctx.Doer)
if err != nil {
log.Error("Unable to GetUserRepoPermission for user %-v in repo %-v Error: %v", ctx.Doer, 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.Doer = user
return true
}
func handleLFSToken(tokenSHA string, target *repo_model.Repository, mode perm.AccessMode) (*user_model.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 == perm.AccessModeWrite && claims.Op != "upload" {
return nil, fmt.Errorf("invalid token claim")
}
u, err := user_model.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 *repo_model.Repository, mode perm.AccessMode) (*user_model.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)
}