fix: enforce public-only token scope and harden push options / locale parsing (#38323) (#38399)

Backport #38323 by @bircni

Three independent security hardening fixes, each with a regression test:

- **Locale DoS:** the `Locale` middleware passed the raw
`Accept-Language` header to `ParseAcceptLanguage`, whose guard only
counts `-` while the scanner aliases `_` to `-` — a large `_`-separated
header on an unauthenticated request burned CPU. The header is now
length-bounded before parsing.
- **Public-only token scope:** `GET /teams/{id}/repos`,
`.../repos/{org}/{repo}`, `/teams/{id}/activities/feeds`, and
`/users/{username}/orgs/{org}/permissions` still returned private
repo/activity/permission data to a public-only token. They now filter
via `TokenCanAccessRepo` / `ApplyPublicOnly` and reject non-public org
permissions.
- **Push-option visibility:** `repo.private` / `repo.template` push
options were applied to any existing repo, letting an owner/admin
silently flip visibility bypassing audit, webhooks, and notifications.
They are now honored only on push-to-create.

Co-authored-by: bircni <bircni@icloud.com>

routers/api/v1/org/org.go

@@ -145,6 +145,13 @@ func GetUserOrgsPermissions(ctx *context.APIContext) {
 
 	op := api.OrganizationPermissions{}
 
+	// A public-only token must not disclose membership/permission details of a
+	// non-public org, even for the token owner's own private orgs.
+	if ctx.PublicOnly && !o.Visibility.IsPublic() {
+		ctx.APIErrorNotFound()
+		return
+	}
+
 	if !organization.HasOrgOrUserVisible(ctx, o, ctx.Doer) {
 		ctx.APIErrorNotFound()
 		return

routers/api/v1/org/team.go

@@ -567,10 +567,20 @@ func GetTeamRepos(ctx *context.APIContext) {
 
 	team := ctx.Org.Team
 	listOptions := utils.GetListOptions(ctx)
-	teamRepos, err := repo_model.GetTeamRepositories(ctx, &repo_model.SearchTeamRepoOptions{
+	// A public-only token must not expose (or count) private repos, even when the
+	// doer owning the token otherwise has access to them, so filter them out at the
+	// query level to keep the returned page and the total-count header consistent.
+	searchOpts := &repo_model.SearchTeamRepoOptions{
 		ListOptions: listOptions,
 		TeamID:      team.ID,
-	})
+		PublicOnly:  ctx.PublicOnly,
+	}
+	teamRepos, err := repo_model.GetTeamRepositories(ctx, searchOpts)
+	if err != nil {
+		ctx.APIErrorInternal(err)
+		return
+	}
+	count, err := repo_model.CountTeamRepositories(ctx, searchOpts)
 	if err != nil {
 		ctx.APIErrorInternal(err)
 		return
@@ -584,14 +594,16 @@ func GetTeamRepos(ctx *context.APIContext) {
 		}
 		// A team's repo list is reachable by non-team-members through the team's
 		// visibility tier, so never expose repos (incl. their names) the doer
-		// cannot access.
+		// cannot access. This per-repo visibility trim can't be expressed in the
+		// SQL count above without regressing per-unit public access, so for such
+		// non-members the total-count header may be a small upper bound.
 		if !permission.HasAnyUnitAccessOrPublicAccess() {
 			continue
 		}
 		repos = append(repos, convert.ToRepo(ctx, repo, permission))
 	}
-	ctx.SetLinkHeader(int64(team.NumRepos), listOptions.PageSize)
-	ctx.SetTotalCountHeader(int64(team.NumRepos))
+	ctx.SetLinkHeader(count, listOptions.PageSize)
+	ctx.SetTotalCountHeader(count)
 	ctx.JSON(http.StatusOK, repos)
 }
 
@@ -630,6 +642,12 @@ func GetTeamRepo(ctx *context.APIContext) {
 		return
 	}
 
+	// A public-only token must not confirm the existence of a private repo.
+	if !ctx.TokenCanAccessRepo(repo) {
+		ctx.APIErrorNotFound()
+		return
+	}
+
 	if !organization.HasTeamRepo(ctx, ctx.Org.Team.OrgID, ctx.Org.Team.ID, repo.ID) {
 		ctx.APIErrorNotFound()
 		return
@@ -889,6 +907,8 @@ func ListTeamActivityFeeds(ctx *context.APIContext) {
 		Date:           ctx.FormString("date"),
 		ListOptions:    listOptions,
 	}
+	// A public-only token must not receive private activity entries.
+	opts.ApplyPublicOnly(ctx.PublicOnly)
 
 	feeds, count, err := feed_service.GetFeeds(ctx, opts)
 	if err != nil {