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Refactor git command package to improve security and maintainability (#22678)

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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>
This commit is contained in:
wxiaoguang 2023-02-04 10:30:43 +08:00 • committed by GitHub
parent 3c5655ce18
commit 6bc3079c00
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
42 changed files with 382 additions and 385 deletions
Download patch file Download diff file Expand all files Collapse all files

80
services/gitdiff/gitdiff.go
View file

@ -1056,7 +1056,7 @@ type DiffOptions struct {
MaxLines int
MaxLineCharacters int
MaxFiles int
WhitespaceBehavior git.CmdArg
WhitespaceBehavior git.TrustedCmdArgs
DirectComparison bool
}
@ -1071,38 +1071,22 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
return nil, err
}
argsLength := 6
if len(opts.WhitespaceBehavior) > 0 {
argsLength++
}
if len(opts.SkipTo) > 0 {
argsLength++
}
if len(files) > 0 {
argsLength += len(files) + 1
}
diffArgs := make([]git.CmdArg, 0, argsLength)
cmdDiff := git.NewCommand(gitRepo.Ctx)
if (len(opts.BeforeCommitID) == 0 || opts.BeforeCommitID == git.EmptySHA) && commit.ParentCount() == 0 {
diffArgs = append(diffArgs, "diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M")
if len(opts.WhitespaceBehavior) != 0 {
diffArgs = append(diffArgs, opts.WhitespaceBehavior)
}
// append empty tree ref
diffArgs = append(diffArgs, "4b825dc642cb6eb9a060e54bf8d69288fbee4904")
diffArgs = append(diffArgs, git.CmdArgCheck(opts.AfterCommitID))
cmdDiff.AddArguments("diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M").
AddArguments(opts.WhitespaceBehavior...).
AddArguments("4b825dc642cb6eb9a060e54bf8d69288fbee4904"). // append empty tree ref
AddDynamicArguments(opts.AfterCommitID)
} else {
actualBeforeCommitID := opts.BeforeCommitID
if len(actualBeforeCommitID) == 0 {
parentCommit, _ := commit.Parent(0)
actualBeforeCommitID = parentCommit.ID.String()
}
diffArgs = append(diffArgs, "diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M")
if len(opts.WhitespaceBehavior) != 0 {
diffArgs = append(diffArgs, opts.WhitespaceBehavior)
}
diffArgs = append(diffArgs, git.CmdArgCheck(actualBeforeCommitID))
diffArgs = append(diffArgs, git.CmdArgCheck(opts.AfterCommitID))
cmdDiff.AddArguments("diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M").
AddArguments(opts.WhitespaceBehavior...).
AddDynamicArguments(actualBeforeCommitID, opts.AfterCommitID)
opts.BeforeCommitID = actualBeforeCommitID
}
@ -1111,16 +1095,11 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
// the skipping for us
parsePatchSkipToFile := opts.SkipTo
if opts.SkipTo != "" && git.CheckGitVersionAtLeast("2.31") == nil {
diffArgs = append(diffArgs, git.CmdArg("--skip-to="+opts.SkipTo))
cmdDiff.AddOptionFormat("--skip-to=%s", opts.SkipTo)
parsePatchSkipToFile = ""
}
if len(files) > 0 {
diffArgs = append(diffArgs, "--")
for _, file := range files {
diffArgs = append(diffArgs, git.CmdArg(file)) // it's safe to cast it to CmdArg because there is a "--" before
}
}
cmdDiff.AddDashesAndList(files...)
reader, writer := io.Pipe()
defer func() {
@ -1128,10 +1107,9 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
_ = writer.Close()
}()
go func(ctx context.Context, diffArgs []git.CmdArg, repoPath string, writer *io.PipeWriter) {
cmd := git.NewCommand(ctx, diffArgs...)
cmd.SetDescription(fmt.Sprintf("GetDiffRange [repo_path: %s]", repoPath))
if err := cmd.Run(&git.RunOpts{
go func() {
cmdDiff.SetDescription(fmt.Sprintf("GetDiffRange [repo_path: %s]", repoPath))
if err := cmdDiff.Run(&git.RunOpts{
Timeout: time.Duration(setting.Git.Timeout.Default) * time.Second,
Dir: repoPath,
Stderr: os.Stderr,
@ -1141,7 +1119,7 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
}
_ = writer.Close()
}(gitRepo.Ctx, diffArgs, repoPath, writer)
}()
diff, err := ParsePatch(opts.MaxLines, opts.MaxLineCharacters, opts.MaxFiles, reader, parsePatchSkipToFile)
if err != nil {
@ -1201,16 +1179,16 @@ func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff
separator = ".."
}
shortstatArgs := []git.CmdArg{git.CmdArgCheck(opts.BeforeCommitID + separator + opts.AfterCommitID)}
diffPaths := []string{opts.BeforeCommitID + separator + opts.AfterCommitID}
if len(opts.BeforeCommitID) == 0 || opts.BeforeCommitID == git.EmptySHA {
shortstatArgs = []git.CmdArg{git.EmptyTreeSHA, git.CmdArgCheck(opts.AfterCommitID)}
diffPaths = []string{git.EmptyTreeSHA, opts.AfterCommitID}
}
diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(gitRepo.Ctx, repoPath, shortstatArgs...)
diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(gitRepo.Ctx, repoPath, nil, diffPaths...)
if err != nil && strings.Contains(err.Error(), "no merge base") {
// git >= 2.28 now returns an error if base and head have become unrelated.
// previously it would return the results of git diff --shortstat base head so let's try that...
shortstatArgs = []git.CmdArg{git.CmdArgCheck(opts.BeforeCommitID), git.CmdArgCheck(opts.AfterCommitID)}
diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(gitRepo.Ctx, repoPath, shortstatArgs...)
diffPaths = []string{opts.BeforeCommitID, opts.AfterCommitID}
diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(gitRepo.Ctx, repoPath, nil, diffPaths...)
}
if err != nil {
return nil, err
@ -1324,17 +1302,17 @@ func CommentMustAsDiff(c *issues_model.Comment) *Diff {
}
// GetWhitespaceFlag returns git diff flag for treating whitespaces
func GetWhitespaceFlag(whitespaceBehavior string) git.CmdArg {
whitespaceFlags := map[string]string{
"ignore-all": "-w",
"ignore-change": "-b",
"ignore-eol": "--ignore-space-at-eol",
"show-all": "",
func GetWhitespaceFlag(whitespaceBehavior string) git.TrustedCmdArgs {
whitespaceFlags := map[string]git.TrustedCmdArgs{
"ignore-all": {"-w"},
"ignore-change": {"-b"},
"ignore-eol": {"--ignore-space-at-eol"},
"show-all": nil,
}
if flag, ok := whitespaceFlags[whitespaceBehavior]; ok {
return git.CmdArg(flag)
return flag
}
log.Warn("unknown whitespace behavior: %q, default to 'show-all'", whitespaceBehavior)
return ""
return nil
}

2
services/gitdiff/gitdiff_test.go
View file

@ -626,7 +626,7 @@ func TestGetDiffRangeWithWhitespaceBehavior(t *testing.T) {
return
}
defer gitRepo.Close()
for _, behavior := range []git.CmdArg{"-w", "--ignore-space-at-eol", "-b", ""} {
for _, behavior := range []git.TrustedCmdArgs{{"-w"}, {"--ignore-space-at-eol"}, {"-b"}, nil} {
diffs, err := GetDiff(gitRepo,
&DiffOptions{
AfterCommitID: "bd7063cc7c04689c4d082183d32a604ed27a24f9",