forgejo/routers/private/hook_verification.go
CaiCandong 815d267c80
Fix verifyCommits error when push a new branch (#26664)
> ### Description
> If a new branch is pushed, and the repository has a rule that would
require signed commits for the new branch, the commit is rejected with a
500 error regardless of whether it's signed.
> 
> When pushing a new branch, the "old" commit is the empty ID
(0000000000000000000000000000000000000000). verifyCommits has no
provision for this and passes an invalid commit range to git rev-list.
Prior to 1.19 this wasn't an issue because only pre-existing individual
branches could be protected.
> 
> I was able to reproduce with
[try.gitea.io/CraigTest/test](https://try.gitea.io/CraigTest/test),
which is set up with a blanket rule to require commits on all branches.


Fix #25565
Very thanks to @Craig-Holmquist-NTI for reporting the bug and suggesting
an valid solution!

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
2023-08-30 02:27:53 +00:00

121 lines
3.3 KiB
Go

// Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package private
import (
"bufio"
"context"
"fmt"
"io"
"os"
asymkey_model "code.gitea.io/gitea/models/asymkey"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/log"
)
// This file contains commit verification functions for refs passed across in hooks
func verifyCommits(oldCommitID, newCommitID string, repo *git.Repository, env []string) error {
stdoutReader, stdoutWriter, err := os.Pipe()
if err != nil {
log.Error("Unable to create os.Pipe for %s", repo.Path)
return err
}
defer func() {
_ = stdoutReader.Close()
_ = stdoutWriter.Close()
}()
var command *git.Command
if oldCommitID == git.EmptySHA {
// When creating a new branch, the oldCommitID is empty, by using "newCommitID --not --all":
// List commits that are reachable by following the newCommitID, exclude "all" existing heads/tags commits
// So, it only lists the new commits received, doesn't list the commits already present in the receiving repository
command = git.NewCommand(repo.Ctx, "rev-list").AddDynamicArguments(newCommitID).AddArguments("--not", "--all")
} else {
command = git.NewCommand(repo.Ctx, "rev-list").AddDynamicArguments(oldCommitID + "..." + newCommitID)
}
// This is safe as force pushes are already forbidden
err = command.Run(&git.RunOpts{
Env: env,
Dir: repo.Path,
Stdout: stdoutWriter,
PipelineFunc: func(ctx context.Context, cancel context.CancelFunc) error {
_ = stdoutWriter.Close()
err := readAndVerifyCommitsFromShaReader(stdoutReader, repo, env)
if err != nil {
log.Error("%v", err)
cancel()
}
_ = stdoutReader.Close()
return err
},
})
if err != nil && !isErrUnverifiedCommit(err) {
log.Error("Unable to check commits from %s to %s in %s: %v", oldCommitID, newCommitID, repo.Path, err)
}
return err
}
func readAndVerifyCommitsFromShaReader(input io.ReadCloser, repo *git.Repository, env []string) error {
scanner := bufio.NewScanner(input)
for scanner.Scan() {
line := scanner.Text()
err := readAndVerifyCommit(line, repo, env)
if err != nil {
log.Error("%v", err)
return err
}
}
return scanner.Err()
}
func readAndVerifyCommit(sha string, repo *git.Repository, env []string) error {
stdoutReader, stdoutWriter, err := os.Pipe()
if err != nil {
log.Error("Unable to create pipe for %s: %v", repo.Path, err)
return err
}
defer func() {
_ = stdoutReader.Close()
_ = stdoutWriter.Close()
}()
hash := git.MustIDFromString(sha)
return git.NewCommand(repo.Ctx, "cat-file", "commit").AddDynamicArguments(sha).
Run(&git.RunOpts{
Env: env,
Dir: repo.Path,
Stdout: stdoutWriter,
PipelineFunc: func(ctx context.Context, cancel context.CancelFunc) error {
_ = stdoutWriter.Close()
commit, err := git.CommitFromReader(repo, hash, stdoutReader)
if err != nil {
return err
}
verification := asymkey_model.ParseCommitWithSignature(ctx, commit)
if !verification.Verified {
cancel()
return &errUnverifiedCommit{
commit.ID.String(),
}
}
return nil
},
})
}
type errUnverifiedCommit struct {
sha string
}
func (e *errUnverifiedCommit) Error() string {
return fmt.Sprintf("Unverified commit: %s", e.sha)
}
func isErrUnverifiedCommit(err error) bool {
_, ok := err.(*errUnverifiedCommit)
return ok
}