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gitea/routers/private/hook_pre_receive.go
Lunny Xiao df7f1c2ead
Fix protected branch files detection on pre_receive hook (#31778)
Fix #31738

When pushing a new branch, the old commit is zero. Most git commands
cannot recognize the zero commit id. To get the changed files in the
push, we need to get the first diverge commit of this branch. In most
situations, we could check commits one by one until one commit is
contained by another branch. Then we will think that commit is the
diverge point.

And in a pre-receive hook, this will be more difficult because all
commits haven't been merged and they actually stored in a temporary
place by git. So we need to bring some envs to let git know the commit
exist.
2024-08-06 13:32:49 +00:00

541 lines
18 KiB
Go

// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package private
import (
"fmt"
"net/http"
"os"
"code.gitea.io/gitea/models"
asymkey_model "code.gitea.io/gitea/models/asymkey"
git_model "code.gitea.io/gitea/models/git"
issues_model "code.gitea.io/gitea/models/issues"
perm_model "code.gitea.io/gitea/models/perm"
access_model "code.gitea.io/gitea/models/perm/access"
"code.gitea.io/gitea/models/unit"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/private"
"code.gitea.io/gitea/modules/web"
gitea_context "code.gitea.io/gitea/services/context"
pull_service "code.gitea.io/gitea/services/pull"
)
type preReceiveContext struct {
*gitea_context.PrivateContext
// loadedPusher indicates that where the following information are loaded
loadedPusher bool
user *user_model.User // it's the org user if a DeployKey is used
userPerm access_model.Permission
deployKeyAccessMode perm_model.AccessMode
canCreatePullRequest bool
checkedCanCreatePullRequest bool
canWriteCode bool
checkedCanWriteCode bool
protectedTags []*git_model.ProtectedTag
gotProtectedTags bool
env []string
opts *private.HookOptions
branchName string
}
// CanWriteCode returns true if pusher can write code
func (ctx *preReceiveContext) CanWriteCode() bool {
if !ctx.checkedCanWriteCode {
if !ctx.loadPusherAndPermission() {
return false
}
ctx.canWriteCode = issues_model.CanMaintainerWriteToBranch(ctx, ctx.userPerm, ctx.branchName, ctx.user) || ctx.deployKeyAccessMode >= perm_model.AccessModeWrite
ctx.checkedCanWriteCode = true
}
return ctx.canWriteCode
}
// AssertCanWriteCode returns true if pusher can write code
func (ctx *preReceiveContext) AssertCanWriteCode() bool {
if !ctx.CanWriteCode() {
if ctx.Written() {
return false
}
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: "User permission denied for writing.",
})
return false
}
return true
}
// CanCreatePullRequest returns true if pusher can create pull requests
func (ctx *preReceiveContext) CanCreatePullRequest() bool {
if !ctx.checkedCanCreatePullRequest {
if !ctx.loadPusherAndPermission() {
return false
}
ctx.canCreatePullRequest = ctx.userPerm.CanRead(unit.TypePullRequests)
ctx.checkedCanCreatePullRequest = true
}
return ctx.canCreatePullRequest
}
// AssertCreatePullRequest returns true if can create pull requests
func (ctx *preReceiveContext) AssertCreatePullRequest() bool {
if !ctx.CanCreatePullRequest() {
if ctx.Written() {
return false
}
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: "User permission denied for creating pull-request.",
})
return false
}
return true
}
// HookPreReceive checks whether a individual commit is acceptable
func HookPreReceive(ctx *gitea_context.PrivateContext) {
opts := web.GetForm(ctx).(*private.HookOptions)
ourCtx := &preReceiveContext{
PrivateContext: ctx,
env: generateGitEnv(opts), // Generate git environment for checking commits
opts: opts,
}
// Iterate across the provided old commit IDs
for i := range opts.OldCommitIDs {
oldCommitID := opts.OldCommitIDs[i]
newCommitID := opts.NewCommitIDs[i]
refFullName := opts.RefFullNames[i]
switch {
case refFullName.IsBranch():
preReceiveBranch(ourCtx, oldCommitID, newCommitID, refFullName)
case refFullName.IsTag():
preReceiveTag(ourCtx, refFullName)
case git.DefaultFeatures().SupportProcReceive && refFullName.IsFor():
preReceiveFor(ourCtx, refFullName)
default:
ourCtx.AssertCanWriteCode()
}
if ctx.Written() {
return
}
}
ctx.PlainText(http.StatusOK, "ok")
}
func preReceiveBranch(ctx *preReceiveContext, oldCommitID, newCommitID string, refFullName git.RefName) {
branchName := refFullName.BranchName()
ctx.branchName = branchName
if !ctx.AssertCanWriteCode() {
return
}
repo := ctx.Repo.Repository
gitRepo := ctx.Repo.GitRepo
objectFormat := ctx.Repo.GetObjectFormat()
if branchName == repo.DefaultBranch && newCommitID == objectFormat.EmptyObjectID().String() {
log.Warn("Forbidden: Branch: %s is the default branch in %-v and cannot be deleted", branchName, repo)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("branch %s is the default branch and cannot be deleted", branchName),
})
return
}
protectBranch, err := git_model.GetFirstMatchProtectedBranchRule(ctx, repo.ID, branchName)
if err != nil {
log.Error("Unable to get protected branch: %s in %-v Error: %v", branchName, repo, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: err.Error(),
})
return
}
// Allow pushes to non-protected branches
if protectBranch == nil {
return
}
protectBranch.Repo = repo
// This ref is a protected branch.
//
// First of all we need to enforce absolutely:
//
// 1. Detect and prevent deletion of the branch
if newCommitID == objectFormat.EmptyObjectID().String() {
log.Warn("Forbidden: Branch: %s in %-v is protected from deletion", branchName, repo)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("branch %s is protected from deletion", branchName),
})
return
}
isForcePush := false
// 2. Disallow force pushes to protected branches
if oldCommitID != objectFormat.EmptyObjectID().String() {
output, _, err := git.NewCommand(ctx, "rev-list", "--max-count=1").AddDynamicArguments(oldCommitID, "^"+newCommitID).RunStdString(&git.RunOpts{Dir: repo.RepoPath(), Env: ctx.env})
if err != nil {
log.Error("Unable to detect force push between: %s and %s in %-v Error: %v", oldCommitID, newCommitID, repo, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Fail to detect force push: %v", err),
})
return
} else if len(output) > 0 {
if protectBranch.CanForcePush {
isForcePush = true
} else {
log.Warn("Forbidden: Branch: %s in %-v is protected from force push", branchName, repo)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("branch %s is protected from force push", branchName),
})
return
}
}
}
// 3. Enforce require signed commits
if protectBranch.RequireSignedCommits {
err := verifyCommits(oldCommitID, newCommitID, gitRepo, ctx.env)
if err != nil {
if !isErrUnverifiedCommit(err) {
log.Error("Unable to check commits from %s to %s in %-v: %v", oldCommitID, newCommitID, repo, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to check commits from %s to %s: %v", oldCommitID, newCommitID, err),
})
return
}
unverifiedCommit := err.(*errUnverifiedCommit).sha
log.Warn("Forbidden: Branch: %s in %-v is protected from unverified commit %s", branchName, repo, unverifiedCommit)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("branch %s is protected from unverified commit %s", branchName, unverifiedCommit),
})
return
}
}
// Now there are several tests which can be overridden:
//
// 4. Check protected file patterns - this is overridable from the UI
changedProtectedfiles := false
protectedFilePath := ""
globs := protectBranch.GetProtectedFilePatterns()
if len(globs) > 0 {
_, err := pull_service.CheckFileProtection(gitRepo, branchName, oldCommitID, newCommitID, globs, 1, ctx.env)
if err != nil {
if !models.IsErrFilePathProtected(err) {
log.Error("Unable to check file protection for commits from %s to %s in %-v: %v", oldCommitID, newCommitID, repo, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to check file protection for commits from %s to %s: %v", oldCommitID, newCommitID, err),
})
return
}
changedProtectedfiles = true
protectedFilePath = err.(models.ErrFilePathProtected).Path
}
}
// 5. Check if the doer is allowed to push (and force-push if the incoming push is a force-push)
var canPush bool
if ctx.opts.DeployKeyID != 0 {
// This flag is only ever true if protectBranch.CanForcePush is true
if isForcePush {
canPush = !changedProtectedfiles && protectBranch.CanPush && (!protectBranch.EnableForcePushAllowlist || protectBranch.ForcePushAllowlistDeployKeys)
} else {
canPush = !changedProtectedfiles && protectBranch.CanPush && (!protectBranch.EnableWhitelist || protectBranch.WhitelistDeployKeys)
}
} else {
user, err := user_model.GetUserByID(ctx, ctx.opts.UserID)
if err != nil {
log.Error("Unable to GetUserByID for commits from %s to %s in %-v: %v", oldCommitID, newCommitID, repo, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to GetUserByID for commits from %s to %s: %v", oldCommitID, newCommitID, err),
})
return
}
if isForcePush {
canPush = !changedProtectedfiles && protectBranch.CanUserForcePush(ctx, user)
} else {
canPush = !changedProtectedfiles && protectBranch.CanUserPush(ctx, user)
}
}
// 6. If we're not allowed to push directly
if !canPush {
// Is this is a merge from the UI/API?
if ctx.opts.PullRequestID == 0 {
// 6a. If we're not merging from the UI/API then there are two ways we got here:
//
// We are changing a protected file and we're not allowed to do that
if changedProtectedfiles {
log.Warn("Forbidden: Branch: %s in %-v is protected from changing file %s", branchName, repo, protectedFilePath)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("branch %s is protected from changing file %s", branchName, protectedFilePath),
})
return
}
// Allow commits that only touch unprotected files
globs := protectBranch.GetUnprotectedFilePatterns()
if len(globs) > 0 {
unprotectedFilesOnly, err := pull_service.CheckUnprotectedFiles(gitRepo, branchName, oldCommitID, newCommitID, globs, ctx.env)
if err != nil {
log.Error("Unable to check file protection for commits from %s to %s in %-v: %v", oldCommitID, newCommitID, repo, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to check file protection for commits from %s to %s: %v", oldCommitID, newCommitID, err),
})
return
}
if unprotectedFilesOnly {
// Commit only touches unprotected files, this is allowed
return
}
}
// Or we're simply not able to push to this protected branch
if isForcePush {
log.Warn("Forbidden: User %d is not allowed to force-push to protected branch: %s in %-v", ctx.opts.UserID, branchName, repo)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("Not allowed to force-push to protected branch %s", branchName),
})
return
}
log.Warn("Forbidden: User %d is not allowed to push to protected branch: %s in %-v", ctx.opts.UserID, branchName, repo)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("Not allowed to push to protected branch %s", branchName),
})
return
}
// 6b. Merge (from UI or API)
// Get the PR, user and permissions for the user in the repository
pr, err := issues_model.GetPullRequestByID(ctx, ctx.opts.PullRequestID)
if err != nil {
log.Error("Unable to get PullRequest %d Error: %v", ctx.opts.PullRequestID, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to get PullRequest %d Error: %v", ctx.opts.PullRequestID, err),
})
return
}
// although we should have called `loadPusherAndPermission` before, here we call it explicitly again because we need to access ctx.user below
if !ctx.loadPusherAndPermission() {
// if error occurs, loadPusherAndPermission had written the error response
return
}
// Now check if the user is allowed to merge PRs for this repository
// Note: we can use ctx.perm and ctx.user directly as they will have been loaded above
allowedMerge, err := pull_service.IsUserAllowedToMerge(ctx, pr, ctx.userPerm, ctx.user)
if err != nil {
log.Error("Error calculating if allowed to merge: %v", err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Error calculating if allowed to merge: %v", err),
})
return
}
if !allowedMerge {
log.Warn("Forbidden: User %d is not allowed to push to protected branch: %s in %-v and is not allowed to merge pr #%d", ctx.opts.UserID, branchName, repo, pr.Index)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("Not allowed to push to protected branch %s", branchName),
})
return
}
// If we're an admin for the repository we can ignore status checks, reviews and override protected files
if ctx.userPerm.IsAdmin() {
return
}
// Now if we're not an admin - we can't overwrite protected files so fail now
if changedProtectedfiles {
log.Warn("Forbidden: Branch: %s in %-v is protected from changing file %s", branchName, repo, protectedFilePath)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("branch %s is protected from changing file %s", branchName, protectedFilePath),
})
return
}
// Check all status checks and reviews are ok
if err := pull_service.CheckPullBranchProtections(ctx, pr, true); err != nil {
if models.IsErrDisallowedToMerge(err) {
log.Warn("Forbidden: User %d is not allowed push to protected branch %s in %-v and pr #%d is not ready to be merged: %s", ctx.opts.UserID, branchName, repo, pr.Index, err.Error())
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("Not allowed to push to protected branch %s and pr #%d is not ready to be merged: %s", branchName, ctx.opts.PullRequestID, err.Error()),
})
return
}
log.Error("Unable to check if mergeable: protected branch %s in %-v and pr #%d. Error: %v", ctx.opts.UserID, branchName, repo, pr.Index, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to get status of pull request %d. Error: %v", ctx.opts.PullRequestID, err),
})
return
}
}
}
func preReceiveTag(ctx *preReceiveContext, refFullName git.RefName) {
if !ctx.AssertCanWriteCode() {
return
}
tagName := refFullName.TagName()
if !ctx.gotProtectedTags {
var err error
ctx.protectedTags, err = git_model.GetProtectedTags(ctx, ctx.Repo.Repository.ID)
if err != nil {
log.Error("Unable to get protected tags for %-v Error: %v", ctx.Repo.Repository, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: err.Error(),
})
return
}
ctx.gotProtectedTags = true
}
isAllowed, err := git_model.IsUserAllowedToControlTag(ctx, ctx.protectedTags, tagName, ctx.opts.UserID)
if err != nil {
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: err.Error(),
})
return
}
if !isAllowed {
log.Warn("Forbidden: Tag %s in %-v is protected", tagName, ctx.Repo.Repository)
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("Tag %s is protected", tagName),
})
return
}
}
func preReceiveFor(ctx *preReceiveContext, refFullName git.RefName) {
if !ctx.AssertCreatePullRequest() {
return
}
if ctx.Repo.Repository.IsEmpty {
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: "Can't create pull request for an empty repository.",
})
return
}
if ctx.opts.IsWiki {
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: "Pull requests are not supported on the wiki.",
})
return
}
baseBranchName := refFullName.ForBranchName()
baseBranchExist := false
if ctx.Repo.GitRepo.IsBranchExist(baseBranchName) {
baseBranchExist = true
}
if !baseBranchExist {
for p, v := range baseBranchName {
if v == '/' && ctx.Repo.GitRepo.IsBranchExist(baseBranchName[:p]) && p != len(baseBranchName)-1 {
baseBranchExist = true
break
}
}
}
if !baseBranchExist {
ctx.JSON(http.StatusForbidden, private.Response{
UserMsg: fmt.Sprintf("Unexpected ref: %s", refFullName),
})
return
}
}
func generateGitEnv(opts *private.HookOptions) (env []string) {
env = os.Environ()
if opts.GitAlternativeObjectDirectories != "" {
env = append(env,
private.GitAlternativeObjectDirectories+"="+opts.GitAlternativeObjectDirectories)
}
if opts.GitObjectDirectory != "" {
env = append(env,
private.GitObjectDirectory+"="+opts.GitObjectDirectory)
}
if opts.GitQuarantinePath != "" {
env = append(env,
private.GitQuarantinePath+"="+opts.GitQuarantinePath)
}
return env
}
// loadPusherAndPermission returns false if an error occurs, and it writes the error response
func (ctx *preReceiveContext) loadPusherAndPermission() bool {
if ctx.loadedPusher {
return true
}
if ctx.opts.UserID == user_model.ActionsUserID {
ctx.user = user_model.NewActionsUser()
ctx.userPerm.AccessMode = perm_model.AccessMode(ctx.opts.ActionPerm)
if err := ctx.Repo.Repository.LoadUnits(ctx); err != nil {
log.Error("Unable to get User id %d Error: %v", ctx.opts.UserID, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to get User id %d Error: %v", ctx.opts.UserID, err),
})
return false
}
ctx.userPerm.SetUnitsWithDefaultAccessMode(ctx.Repo.Repository.Units, ctx.userPerm.AccessMode)
} else {
user, err := user_model.GetUserByID(ctx, ctx.opts.UserID)
if err != nil {
log.Error("Unable to get User id %d Error: %v", ctx.opts.UserID, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to get User id %d Error: %v", ctx.opts.UserID, err),
})
return false
}
ctx.user = user
userPerm, err := access_model.GetUserRepoPermission(ctx, ctx.Repo.Repository, user)
if err != nil {
log.Error("Unable to get Repo permission of repo %s/%s of User %s: %v", ctx.Repo.Repository.OwnerName, ctx.Repo.Repository.Name, user.Name, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to get Repo permission of repo %s/%s of User %s: %v", ctx.Repo.Repository.OwnerName, ctx.Repo.Repository.Name, user.Name, err),
})
return false
}
ctx.userPerm = userPerm
}
if ctx.opts.DeployKeyID != 0 {
deployKey, err := asymkey_model.GetDeployKeyByID(ctx, ctx.opts.DeployKeyID)
if err != nil {
log.Error("Unable to get DeployKey id %d Error: %v", ctx.opts.DeployKeyID, err)
ctx.JSON(http.StatusInternalServerError, private.Response{
Err: fmt.Sprintf("Unable to get DeployKey id %d Error: %v", ctx.opts.DeployKeyID, err),
})
return false
}
ctx.deployKeyAccessMode = deployKey.Mode
}
ctx.loadedPusher = true
return true
}