fix: Various security fixes (#38103)

- Enforce org visibility on organization label read endpoints (private
org labels no longer leak to non-members).
- Block fork sync (`merge-upstream`) when the base repo is no longer
readable (stops pulling commits after a parent goes private).
- Remove `REVERSE_PROXY_LIMIT` / `REVERSE_PROXY_TRUSTED_PROXIES` from
the Docker `app.ini` templates (the `= *` default allowed
`X-WEBAUTH-USER` impersonation; reverse-proxy auth is now opt-in and
admin-configured).
- Enforce single-use TOTP passcodes across web login, password-reset,
and Basic-Auth `X-Gitea-OTP` (fixes a TOCTOU race and a stateless
replay).
- Re-check branch write permission for every ref in a push (the
pre-receive hook cached the first ref's result, letting a per-branch
maintainer-edit grant escalate to full repo write).

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/api/v1/api.go

@@ -505,6 +505,21 @@ func reqOrgOwnership() func(ctx *context.APIContext) {
 	}
 }
 
+// reqOrgVisible requires the organization to be visible to the doer, or a site admin
+func reqOrgVisible() func(ctx *context.APIContext) {
+	return func(ctx *context.APIContext) {
+		if ctx.Org.Organization == nil {
+			setting.PanicInDevOrTesting("reqOrgVisible: unprepared context")
+			ctx.APIErrorInternal(errors.New("reqOrgVisible: unprepared context"))
+			return
+		}
+		if !organization.HasOrgOrUserVisible(ctx, ctx.Org.Organization.AsUser(), ctx.Doer) {
+			ctx.APIErrorNotFound()
+			return
+		}
+	}
+}
+
 func teamAccessPrivileged(ctx *context.APIContext) (orgID int64, privileged, ok bool) {
 	if ctx.IsUserSiteAdmin() {
 		return 0, true, true
@@ -1728,7 +1743,7 @@ func Routes() *web.Router {
 				m.Combo("/{id}").Get(reqToken(), org.GetLabel).
 					Patch(reqToken(), reqOrgOwnership(), bind(api.EditLabelOption{}), org.EditLabel).
 					Delete(reqToken(), reqOrgOwnership(), org.DeleteLabel)
-			})
+			}, reqOrgVisible())
 			m.Group("/hooks", func() {
 				m.Combo("").Get(org.ListHooks).
 					Post(bind(api.CreateHookOption{}), org.CreateHook)

routers/api/v1/repo/branch.go

@@ -1336,6 +1336,9 @@ func MergeUpstream(ctx *context.APIContext) {
 		} else if errors.Is(err, util.ErrNotExist) {
 			ctx.APIError(http.StatusNotFound, err.Error())
 			return
+		} else if errors.Is(err, util.ErrPermissionDenied) {
+			ctx.APIError(http.StatusForbidden, err.Error())
+			return
 		}
 		ctx.APIErrorInternal(err)
 		return

routers/private/hook_pre_receive.go

@@ -40,9 +40,6 @@ type preReceiveContext struct {
 	canCreatePullRequest        bool
 	checkedCanCreatePullRequest bool
 
-	canWriteCode        bool
-	checkedCanWriteCode bool
-
 	protectedTags    []*git_model.ProtectedTag
 	gotProtectedTags bool
 
@@ -50,24 +47,36 @@ type preReceiveContext struct {
 
 	opts *private.HookOptions
 
-	branchName string
+	// this context should only contain shared variables, mutable variables like "current branch name" shouldn't be put here
+	canWriteCodeUnitCached *bool
 }
 
-// CanWriteCode returns true if pusher can write code
-func (ctx *preReceiveContext) CanWriteCode() bool {
-	if !ctx.checkedCanWriteCode {
-		if !ctx.loadPusherAndPermission() {
-			return false
+func (ctx *preReceiveContext) canWriteCodeUnit() bool {
+	if ctx.canWriteCodeUnitCached == nil {
+		var canWrite bool
+		if ctx.loadPusherAndPermission() {
+			canWrite = ctx.userPerm.CanWrite(unit.TypeCode) || ctx.deployKeyAccessMode >= perm_model.AccessModeWrite
 		}
-		ctx.canWriteCode = issues_model.CanMaintainerWriteToBranch(ctx, ctx.userPerm, ctx.branchName, ctx.user) || ctx.deployKeyAccessMode >= perm_model.AccessModeWrite
-		ctx.checkedCanWriteCode = true
+		ctx.canWriteCodeUnitCached = &canWrite
 	}
-	return ctx.canWriteCode
+	return *ctx.canWriteCodeUnitCached
 }
 
-// AssertCanWriteCode returns true if pusher can write code
-func (ctx *preReceiveContext) AssertCanWriteCode() bool {
-	if !ctx.CanWriteCode() {
+// canWriteCodeRef returns true if pusher can write to the code ref (branch/tag/commit)
+func (ctx *preReceiveContext) canWriteCodeRef(refFullName git.RefName) bool {
+	if ctx.canWriteCodeUnit() {
+		return true
+	}
+	// then check whether if the pusher is a maintainer who can write the PR author's head repo branch
+	if !refFullName.IsBranch() {
+		return false
+	}
+	return issues_model.CanMaintainerWriteToBranch(ctx, ctx.userPerm, refFullName.BranchName(), ctx.user)
+}
+
+// assertCanWriteRef returns true if pusher can write to the code ref, otherwise it responds with 403 Forbidden and returns false
+func (ctx *preReceiveContext) assertCanWriteRef(refFullName git.RefName) bool {
+	if !ctx.canWriteCodeRef(refFullName) {
 		if ctx.Written() {
 			return false
 		}
@@ -129,7 +138,7 @@ func HookPreReceive(ctx *gitea_context.PrivateContext) {
 		case git.DefaultFeatures().SupportProcReceive && refFullName.IsFor():
 			preReceiveFor(ourCtx, refFullName)
 		default:
-			ourCtx.AssertCanWriteCode()
+			ourCtx.assertCanWriteRef(refFullName)
 		}
 		if ctx.Written() {
 			return
@@ -141,9 +150,8 @@ func HookPreReceive(ctx *gitea_context.PrivateContext) {
 
 func preReceiveBranch(ctx *preReceiveContext, oldCommitID, newCommitID string, refFullName git.RefName) {
 	branchName := refFullName.BranchName()
-	ctx.branchName = branchName
 
-	if !ctx.AssertCanWriteCode() {
+	if !ctx.assertCanWriteRef(refFullName) {
 		return
 	}
 
@@ -404,7 +412,7 @@ func preReceiveBranch(ctx *preReceiveContext, oldCommitID, newCommitID string, r
 }
 
 func preReceiveTag(ctx *preReceiveContext, refFullName git.RefName) {
-	if !ctx.AssertCanWriteCode() {
+	if !ctx.assertCanWriteRef(refFullName) {
 		return
 	}
 

routers/private/hook_pre_receive_test.go

@@ -0,0 +1,70 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package private
+
+import (
+	"testing"
+
+	issues_model "gitea.dev/models/issues"
+	"gitea.dev/models/perm/access"
+	repo_model "gitea.dev/models/repo"
+	"gitea.dev/models/unittest"
+	"gitea.dev/modules/git"
+	"gitea.dev/services/contexttest"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestPreReceiveCanWriteCodePerBranch ensures the maintainer-edit write grant is evaluated against
+// the exact ref being pushed on every call, derived from that ref rather than shared mutable state.
+// Otherwise a per-branch grant (an open PR with "allow edits from maintainers") could be batched
+// together with a protected branch or a tag to escalate into full repository write.
+func TestPreReceiveCanWriteCodePerBranch(t *testing.T) {
+	require.NoError(t, unittest.PrepareTestDatabase())
+
+	baseRepo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 10})
+	headRepo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 11})
+	require.NoError(t, baseRepo.LoadOwner(t.Context()))
+	require.NoError(t, headRepo.LoadOwner(t.Context()))
+
+	// An open PR from the head repo owner, with maintainer edits allowed: this grants the base
+	// repo owner write access to exactly this head branch and nothing else.
+	pr := &issues_model.PullRequest{
+		Issue: &issues_model.Issue{
+			RepoID:   baseRepo.ID,
+			PosterID: headRepo.OwnerID,
+		},
+		HeadRepoID:          headRepo.ID,
+		BaseRepoID:          baseRepo.ID,
+		HeadBranch:          "granted-branch",
+		BaseBranch:          "master",
+		AllowMaintainerEdit: true,
+	}
+	require.NoError(t, issues_model.NewPullRequest(t.Context(), baseRepo, pr.Issue, nil, nil, pr))
+
+	// The pusher is the base repo owner (the maintainer) with only read access on the head repo.
+	maintainer := baseRepo.Owner
+	headPerm, err := access.GetIndividualUserRepoPermission(t.Context(), headRepo, maintainer)
+	require.NoError(t, err)
+
+	mockCtx, _ := contexttest.MockPrivateContext(t, "/")
+	ctx := &preReceiveContext{
+		PrivateContext: mockCtx,
+		loadedPusher:   true,
+		user:           maintainer,
+		userPerm:       headPerm,
+	}
+
+	// The granted branch must be writable...
+	assert.True(t, ctx.canWriteCodeRef(git.RefNameFromBranch("granted-branch")))
+
+	// ...but another branch in the same push must NOT inherit that grant.
+	assert.False(t, ctx.canWriteCodeRef(git.RefNameFromBranch("master")))
+
+	// ...and a tag sharing the granted branch's name must NOT inherit it either: the grant is
+	// scoped to PR head branches, so a non-branch ref can never match it. (A tag ref already
+	// yields an empty branch name, so this guards the per-ref evaluation, not the IsBranch check.)
+	assert.False(t, ctx.canWriteCodeRef(git.RefNameFromTag("granted-branch")))
+}

routers/web/auth/2fa.go

@@ -58,14 +58,14 @@ func TwoFactorPost(ctx *context.Context) {
 		return
 	}
 
-	// Validate the passcode with the stored TOTP secret.
-	ok, err := twofa.ValidateTOTP(form.Passcode)
+	// Validate the passcode and atomically consume it to prevent reuse/replay.
+	ok, err := twofa.ValidateAndConsumeTOTP(ctx, form.Passcode)
 	if err != nil {
 		ctx.ServerError("UserSignIn", err)
 		return
 	}
 
-	if ok && twofa.LastUsedPasscode != form.Passcode {
+	if ok {
 		remember := ctx.Session.Get("twofaRemember").(bool)
 		u, err := user_model.GetUserByID(ctx, id)
 		if err != nil {
@@ -81,12 +81,6 @@ func TwoFactorPost(ctx *context.Context) {
 			}
 		}
 
-		twofa.LastUsedPasscode = form.Passcode
-		if err = auth.UpdateTwoFactor(ctx, twofa); err != nil {
-			ctx.ServerError("UserSignIn", err)
-			return
-		}
-
 		_ = ctx.Session.Set(session.KeyUserHasTwoFactorAuth, true)
 		handleSignIn(ctx, u, remember)
 		return

routers/web/auth/password.go

@@ -177,23 +177,17 @@ func ResetPasswdPost(ctx *context.Context) {
 			regenerateScratchToken = true
 		} else {
 			passcode := ctx.FormString("passcode")
-			ok, err := twofa.ValidateTOTP(passcode)
+			ok, err := twofa.ValidateAndConsumeTOTP(ctx, passcode)
 			if err != nil {
-				ctx.HTTPError(http.StatusInternalServerError, "ValidateTOTP", err.Error())
+				ctx.HTTPError(http.StatusInternalServerError, "ValidateAndConsumeTOTP", err.Error())
 				return
 			}
-			if !ok || twofa.LastUsedPasscode == passcode {
+			if !ok {
 				ctx.Data["IsResetForm"] = true
 				ctx.Data["Err_Passcode"] = true
 				ctx.RenderWithErrDeprecated(ctx.Tr("auth.twofa_passcode_incorrect"), tplResetPassword, nil)
 				return
 			}
-
-			twofa.LastUsedPasscode = passcode
-			if err = auth.UpdateTwoFactor(ctx, twofa); err != nil {
-				ctx.ServerError("ResetPasswdPost: UpdateTwoFactor", err)
-				return
-			}
 		}
 	}
 

routers/web/repo/branch.go

@@ -264,7 +264,7 @@ func MergeUpstream(ctx *context.Context) {
 	branchName := ctx.FormString("branch")
 	_, err := repo_service.MergeUpstream(ctx, ctx.Doer, ctx.Repo.Repository, branchName, false)
 	if err != nil {
-		if errors.Is(err, util.ErrNotExist) {
+		if errors.Is(err, util.ErrNotExist) || errors.Is(err, util.ErrPermissionDenied) {
 			ctx.JSONErrorNotFound()
 			return
 		} else if pull_service.IsErrMergeConflicts(err) {