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forgejo/services/repository/files/update.go
wxiaoguang 6bc3079c00
Refactor git command package to improve security and maintainability (#22678)
This PR follows #21535 (and replace #22592)

## Review without space diff

https://github.com/go-gitea/gitea/pull/22678/files?diff=split&w=1

## Purpose of this PR

1. Make git module command completely safe (risky user inputs won't be
passed as argument option anymore)
2. Avoid low-level mistakes like
https://github.com/go-gitea/gitea/pull/22098#discussion_r1045234918
3. Remove deprecated and dirty `CmdArgCheck` function, hide the `CmdArg`
type
4. Simplify code when using git command

## The main idea of this PR

* Move the `git.CmdArg` to the `internal` package, then no other package
except `git` could use it. Then developers could never do
`AddArguments(git.CmdArg(userInput))` any more.
* Introduce `git.ToTrustedCmdArgs`, it's for user-provided and already
trusted arguments. It's only used in a few cases, for example: use git
arguments from config file, help unit test with some arguments.
* Introduce `AddOptionValues` and `AddOptionFormat`, they make code more
clear and simple:
    * Before: `AddArguments("-m").AddDynamicArguments(message)`
    * After: `AddOptionValues("-m", message)`
    * -
* Before: `AddArguments(git.CmdArg(fmt.Sprintf("--author='%s <%s>'",
sig.Name, sig.Email)))`
* After: `AddOptionFormat("--author='%s <%s>'", sig.Name, sig.Email)`

## FAQ

### Why these changes were not done in #21535 ?

#21535 is mainly a search&replace, it did its best to not change too
much logic.

Making the framework better needs a lot of changes, so this separate PR
is needed as the second step.


### The naming of `AddOptionXxx`

According to git's manual, the `--xxx` part is called `option`.

### How can it guarantee that `internal.CmdArg` won't be not misused?

Go's specification guarantees that. Trying to access other package's
internal package causes compilation error.

And, `golangci-lint` also denies the git/internal package. Only the
`git/command.go` can use it carefully.

### There is still a `ToTrustedCmdArgs`, will it still allow developers
to make mistakes and pass untrusted arguments?

Generally speaking, no. Because when using `ToTrustedCmdArgs`, the code
will be very complex (see the changes for examples). Then developers and
reviewers can know that something might be unreasonable.

### Why there was a `CmdArgCheck` and why it's removed?

At the moment of #21535, to reduce unnecessary changes, `CmdArgCheck`
was introduced as a hacky patch. Now, almost all code could be written
as `cmd := NewCommand(); cmd.AddXxx(...)`, then there is no need for
`CmdArgCheck` anymore.


### Why many codes for `signArg == ""` is deleted?

Because in the old code, `signArg` could never be empty string, it's
either `-S[key-id]` or `--no-gpg-sign`. So the `signArg == ""` is just
dead code.

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
2023-02-04 10:30:43 +08:00

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// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package files
import (
"bytes"
"context"
"fmt"
"path"
"strings"
"time"
"code.gitea.io/gitea/models"
"code.gitea.io/gitea/models/db"
git_model "code.gitea.io/gitea/models/git"
repo_model "code.gitea.io/gitea/models/repo"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/charset"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/lfs"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/structs"
"code.gitea.io/gitea/modules/util"
asymkey_service "code.gitea.io/gitea/services/asymkey"
stdcharset "golang.org/x/net/html/charset"
"golang.org/x/text/transform"
)
// IdentityOptions for a person's identity like an author or committer
type IdentityOptions struct {
Name string
Email string
}
// CommitDateOptions store dates for GIT_AUTHOR_DATE and GIT_COMMITTER_DATE
type CommitDateOptions struct {
Author time.Time
Committer time.Time
}
// UpdateRepoFileOptions holds the repository file update options
type UpdateRepoFileOptions struct {
LastCommitID string
OldBranch string
NewBranch string
TreePath string
FromTreePath string
Message string
Content string
SHA string
IsNewFile bool
Author *IdentityOptions
Committer *IdentityOptions
Dates *CommitDateOptions
Signoff bool
}
func detectEncodingAndBOM(entry *git.TreeEntry, repo *repo_model.Repository) (string, bool) {
reader, err := entry.Blob().DataAsync()
if err != nil {
// return default
return "UTF-8", false
}
defer reader.Close()
buf := make([]byte, 1024)
n, err := util.ReadAtMost(reader, buf)
if err != nil {
// return default
return "UTF-8", false
}
buf = buf[:n]
if setting.LFS.StartServer {
pointer, _ := lfs.ReadPointerFromBuffer(buf)
if pointer.IsValid() {
meta, err := git_model.GetLFSMetaObjectByOid(db.DefaultContext, repo.ID, pointer.Oid)
if err != nil && err != git_model.ErrLFSObjectNotExist {
// return default
return "UTF-8", false
}
if meta != nil {
dataRc, err := lfs.ReadMetaObject(pointer)
if err != nil {
// return default
return "UTF-8", false
}
defer dataRc.Close()
buf = make([]byte, 1024)
n, err = util.ReadAtMost(dataRc, buf)
if err != nil {
// return default
return "UTF-8", false
}
buf = buf[:n]
}
}
}
encoding, err := charset.DetectEncoding(buf)
if err != nil {
// just default to utf-8 and no bom
return "UTF-8", false
}
if encoding == "UTF-8" {
return encoding, bytes.Equal(buf[0:3], charset.UTF8BOM)
}
charsetEncoding, _ := stdcharset.Lookup(encoding)
if charsetEncoding == nil {
return "UTF-8", false
}
result, n, err := transform.String(charsetEncoding.NewDecoder(), string(buf))
if err != nil {
// return default
return "UTF-8", false
}
if n > 2 {
return encoding, bytes.Equal([]byte(result)[0:3], charset.UTF8BOM)
}
return encoding, false
}
// CreateOrUpdateRepoFile adds or updates a file in the given repository
func CreateOrUpdateRepoFile(ctx context.Context, repo *repo_model.Repository, doer *user_model.User, opts *UpdateRepoFileOptions) (*structs.FileResponse, error) {
// If no branch name is set, assume default branch
if opts.OldBranch == "" {
opts.OldBranch = repo.DefaultBranch
}
if opts.NewBranch == "" {
opts.NewBranch = opts.OldBranch
}
gitRepo, closer, err := git.RepositoryFromContextOrOpen(ctx, repo.RepoPath())
if err != nil {
return nil, err
}
defer closer.Close()
// oldBranch must exist for this operation
if _, err := gitRepo.GetBranch(opts.OldBranch); err != nil && !repo.IsEmpty {
return nil, err
}
// A NewBranch can be specified for the file to be created/updated in a new branch.
// Check to make sure the branch does not already exist, otherwise we can't proceed.
// If we aren't branching to a new branch, make sure user can commit to the given branch
if opts.NewBranch != opts.OldBranch {
existingBranch, err := gitRepo.GetBranch(opts.NewBranch)
if existingBranch != nil {
return nil, models.ErrBranchAlreadyExists{
BranchName: opts.NewBranch,
}
}
if err != nil && !git.IsErrBranchNotExist(err) {
return nil, err
}
} else if err := VerifyBranchProtection(ctx, repo, doer, opts.OldBranch, opts.TreePath); err != nil {
return nil, err
}
// If FromTreePath is not set, set it to the opts.TreePath
if opts.TreePath != "" && opts.FromTreePath == "" {
opts.FromTreePath = opts.TreePath
}
// Check that the path given in opts.treePath is valid (not a git path)
treePath := CleanUploadFileName(opts.TreePath)
if treePath == "" {
return nil, models.ErrFilenameInvalid{
Path: opts.TreePath,
}
}
// If there is a fromTreePath (we are copying it), also clean it up
fromTreePath := CleanUploadFileName(opts.FromTreePath)
if fromTreePath == "" && opts.FromTreePath != "" {
return nil, models.ErrFilenameInvalid{
Path: opts.FromTreePath,
}
}
message := strings.TrimSpace(opts.Message)
author, committer := GetAuthorAndCommitterUsers(opts.Author, opts.Committer, doer)
t, err := NewTemporaryUploadRepository(ctx, repo)
if err != nil {
log.Error("%v", err)
}
defer t.Close()
hasOldBranch := true
if err := t.Clone(opts.OldBranch); err != nil {
if !git.IsErrBranchNotExist(err) || !repo.IsEmpty {
return nil, err
}
if err := t.Init(); err != nil {
return nil, err
}
hasOldBranch = false
opts.LastCommitID = ""
}
if hasOldBranch {
if err := t.SetDefaultIndex(); err != nil {
return nil, err
}
}
encoding := "UTF-8"
bom := false
executable := false
if hasOldBranch {
// Get the commit of the original branch
commit, err := t.GetBranchCommit(opts.OldBranch)
if err != nil {
return nil, err // Couldn't get a commit for the branch
}
// Assigned LastCommitID in opts if it hasn't been set
if opts.LastCommitID == "" {
opts.LastCommitID = commit.ID.String()
} else {
lastCommitID, err := t.gitRepo.ConvertToSHA1(opts.LastCommitID)
if err != nil {
return nil, fmt.Errorf("ConvertToSHA1: Invalid last commit ID: %w", err)
}
opts.LastCommitID = lastCommitID.String()
}
if !opts.IsNewFile {
fromEntry, err := commit.GetTreeEntryByPath(fromTreePath)
if err != nil {
return nil, err
}
if opts.SHA != "" {
// If a SHA was given and the SHA given doesn't match the SHA of the fromTreePath, throw error
if opts.SHA != fromEntry.ID.String() {
return nil, models.ErrSHADoesNotMatch{
Path: treePath,
GivenSHA: opts.SHA,
CurrentSHA: fromEntry.ID.String(),
}
}
} else if opts.LastCommitID != "" {
// If a lastCommitID was given and it doesn't match the commitID of the head of the branch throw
// an error, but only if we aren't creating a new branch.
if commit.ID.String() != opts.LastCommitID && opts.OldBranch == opts.NewBranch {
if changed, err := commit.FileChangedSinceCommit(treePath, opts.LastCommitID); err != nil {
return nil, err
} else if changed {
return nil, models.ErrCommitIDDoesNotMatch{
GivenCommitID: opts.LastCommitID,
CurrentCommitID: opts.LastCommitID,
}
}
// The file wasn't modified, so we are good to delete it
}
} else {
// When updating a file, a lastCommitID or SHA needs to be given to make sure other commits
// haven't been made. We throw an error if one wasn't provided.
return nil, models.ErrSHAOrCommitIDNotProvided{}
}
encoding, bom = detectEncodingAndBOM(fromEntry, repo)
executable = fromEntry.IsExecutable()
}
// For the path where this file will be created/updated, we need to make
// sure no parts of the path are existing files or links except for the last
// item in the path which is the file name, and that shouldn't exist IF it is
// a new file OR is being moved to a new path.
treePathParts := strings.Split(treePath, "/")
subTreePath := ""
for index, part := range treePathParts {
subTreePath = path.Join(subTreePath, part)
entry, err := commit.GetTreeEntryByPath(subTreePath)
if err != nil {
if git.IsErrNotExist(err) {
// Means there is no item with that name, so we're good
break
}
return nil, err
}
if index < len(treePathParts)-1 {
if !entry.IsDir() {
return nil, models.ErrFilePathInvalid{
Message: fmt.Sprintf("a file exists where youre trying to create a subdirectory [path: %s]", subTreePath),
Path: subTreePath,
Name: part,
Type: git.EntryModeBlob,
}
}
} else if entry.IsLink() {
return nil, models.ErrFilePathInvalid{
Message: fmt.Sprintf("a symbolic link exists where youre trying to create a subdirectory [path: %s]", subTreePath),
Path: subTreePath,
Name: part,
Type: git.EntryModeSymlink,
}
} else if entry.IsDir() {
return nil, models.ErrFilePathInvalid{
Message: fmt.Sprintf("a directory exists where youre trying to create a file [path: %s]", subTreePath),
Path: subTreePath,
Name: part,
Type: git.EntryModeTree,
}
} else if fromTreePath != treePath || opts.IsNewFile {
// The entry shouldn't exist if we are creating new file or moving to a new path
return nil, models.ErrRepoFileAlreadyExists{
Path: treePath,
}
}
}
}
// Get the two paths (might be the same if not moving) from the index if they exist
filesInIndex, err := t.LsFiles(opts.TreePath, opts.FromTreePath)
if err != nil {
return nil, fmt.Errorf("UpdateRepoFile: %w", err)
}
// If is a new file (not updating) then the given path shouldn't exist
if opts.IsNewFile {
for _, file := range filesInIndex {
if file == opts.TreePath {
return nil, models.ErrRepoFileAlreadyExists{
Path: opts.TreePath,
}
}
}
}
// Remove the old path from the tree
if fromTreePath != treePath && len(filesInIndex) > 0 {
for _, file := range filesInIndex {
if file == fromTreePath {
if err := t.RemoveFilesFromIndex(opts.FromTreePath); err != nil {
return nil, err
}
}
}
}
content := opts.Content
if bom {
content = string(charset.UTF8BOM) + content
}
if encoding != "UTF-8" {
charsetEncoding, _ := stdcharset.Lookup(encoding)
if charsetEncoding != nil {
result, _, err := transform.String(charsetEncoding.NewEncoder(), content)
if err != nil {
// Look if we can't encode back in to the original we should just stick with utf-8
log.Error("Error re-encoding %s (%s) as %s - will stay as UTF-8: %v", opts.TreePath, opts.FromTreePath, encoding, err)
result = content
}
content = result
} else {
log.Error("Unknown encoding: %s", encoding)
}
}
// Reset the opts.Content to our adjusted content to ensure that LFS gets the correct content
opts.Content = content
var lfsMetaObject *git_model.LFSMetaObject
if setting.LFS.StartServer && hasOldBranch {
// Check there is no way this can return multiple infos
filename2attribute2info, err := t.gitRepo.CheckAttribute(git.CheckAttributeOpts{
Attributes: []string{"filter"},
Filenames: []string{treePath},
CachedOnly: true,
})
if err != nil {
return nil, err
}
if filename2attribute2info[treePath] != nil && filename2attribute2info[treePath]["filter"] == "lfs" {
// OK so we are supposed to LFS this data!
pointer, err := lfs.GeneratePointer(strings.NewReader(opts.Content))
if err != nil {
return nil, err
}
lfsMetaObject = &git_model.LFSMetaObject{Pointer: pointer, RepositoryID: repo.ID}
content = pointer.StringContent()
}
}
// Add the object to the database
objectHash, err := t.HashObject(strings.NewReader(content))
if err != nil {
return nil, err
}
// Add the object to the index
if executable {
if err := t.AddObjectToIndex("100755", objectHash, treePath); err != nil {
return nil, err
}
} else {
if err := t.AddObjectToIndex("100644", objectHash, treePath); err != nil {
return nil, err
}
}
// Now write the tree
treeHash, err := t.WriteTree()
if err != nil {
return nil, err
}
// Now commit the tree
var commitHash string
if opts.Dates != nil {
commitHash, err = t.CommitTreeWithDate(opts.LastCommitID, author, committer, treeHash, message, opts.Signoff, opts.Dates.Author, opts.Dates.Committer)
} else {
commitHash, err = t.CommitTree(opts.LastCommitID, author, committer, treeHash, message, opts.Signoff)
}
if err != nil {
return nil, err
}
if lfsMetaObject != nil {
// We have an LFS object - create it
lfsMetaObject, err = git_model.NewLFSMetaObject(ctx, lfsMetaObject)
if err != nil {
return nil, err
}
contentStore := lfs.NewContentStore()
exist, err := contentStore.Exists(lfsMetaObject.Pointer)
if err != nil {
return nil, err
}
if !exist {
if err := contentStore.Put(lfsMetaObject.Pointer, strings.NewReader(opts.Content)); err != nil {
if _, err2 := git_model.RemoveLFSMetaObjectByOid(ctx, repo.ID, lfsMetaObject.Oid); err2 != nil {
return nil, fmt.Errorf("Error whilst removing failed inserted LFS object %s: %v (Prev Error: %w)", lfsMetaObject.Oid, err2, err)
}
return nil, err
}
}
}
// Then push this tree to NewBranch
if err := t.Push(doer, commitHash, opts.NewBranch); err != nil {
log.Error("%T %v", err, err)
return nil, err
}
commit, err := t.GetCommit(commitHash)
if err != nil {
return nil, err
}
file, err := GetFileResponseFromCommit(ctx, repo, commit, opts.NewBranch, treePath)
if err != nil {
return nil, err
}
return file, nil
}
// VerifyBranchProtection verify the branch protection for modifying the given treePath on the given branch
func VerifyBranchProtection(ctx context.Context, repo *repo_model.Repository, doer *user_model.User, branchName, treePath string) error {
protectedBranch, err := git_model.GetFirstMatchProtectedBranchRule(ctx, repo.ID, branchName)
if err != nil {
return err
}
if protectedBranch != nil {
protectedBranch.Repo = repo
isUnprotectedFile := false
glob := protectedBranch.GetUnprotectedFilePatterns()
if len(glob) != 0 {
isUnprotectedFile = protectedBranch.IsUnprotectedFile(glob, treePath)
}
if !protectedBranch.CanUserPush(ctx, doer) && !isUnprotectedFile {
return models.ErrUserCannotCommit{
UserName: doer.LowerName,
}
}
if protectedBranch.RequireSignedCommits {
_, _, _, err := asymkey_service.SignCRUDAction(ctx, repo.RepoPath(), doer, repo.RepoPath(), branchName)
if err != nil {
if !asymkey_service.IsErrWontSign(err) {
return err
}
return models.ErrUserCannotCommit{
UserName: doer.LowerName,
}
}
}
patterns := protectedBranch.GetProtectedFilePatterns()
for _, pat := range patterns {
if pat.Match(strings.ToLower(treePath)) {
return models.ErrFilePathProtected{
Path: treePath,
}
}
}
}
return nil
}