Files
gitea/services/actions/permission_parser.go
T
silverwind d8e179f28f fix: resolve YAML anchors and aliases in Actions workflows (#38984) (#38996)
Backport https://github.com/go-gitea/gitea/pull/38984

Workflows using YAML anchors are rejected as invalid, because a workflow
is split into one document per job and an alias whose anchor lands in
another job's document no longer resolves. Node walkers such as `on:`
parsing have no alias case either.

Aliases are now expanded once, right after the workflow is parsed and
before anything reads or splits it, bounded like GitHub's parser so
nested aliases cannot expand without limit. Merge keys stay unsupported,
as they are upstream.

Fixes: https://github.com/go-gitea/gitea/issues/38983
2026-08-20 11:16:33 +02:00

143 lines
4.1 KiB
Go

// Copyright 2026 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package actions
import (
"gitea.dev/models/perm"
repo_model "gitea.dev/models/repo"
"gitea.dev/models/unit"
"gitea.dev/modules/actions/jobparser"
"gitea.dev/modules/setting"
"go.yaml.in/yaml/v4"
)
// ExtractJobPermissionsFromWorkflow extracts permissions from an already parsed workflow/job.
// It returns nil if neither workflow nor job explicitly specifies permissions.
func ExtractJobPermissionsFromWorkflow(flow *jobparser.SingleWorkflow, job *jobparser.Job) *repo_model.ActionsTokenPermissions {
if flow == nil || job == nil {
return nil
}
jobPerms := parseRawPermissionsExplicit(&job.RawPermissions)
if jobPerms != nil {
return jobPerms
}
workflowPerms := parseRawPermissionsExplicit(&flow.RawPermissions)
if workflowPerms != nil {
return workflowPerms
}
return nil
}
// parseRawPermissionsExplicit parses a YAML permissions node and returns only explicit scopes.
// It returns nil if the node does not explicitly specify permissions.
func parseRawPermissionsExplicit(rawPerms *yaml.Node) *repo_model.ActionsTokenPermissions {
if rawPerms == nil || (rawPerms.Kind == yaml.ScalarNode && rawPerms.Value == "") {
return nil
}
// Unwrap DocumentNode
node := rawPerms
for node.Kind == yaml.DocumentNode {
if len(node.Content) == 0 {
return nil
}
node = node.Content[0]
}
if node.Kind == yaml.ScalarNode && node.Value == "" {
return nil
}
// Handle scalar values: "read-all" or "write-all"
if node.Kind == yaml.ScalarNode {
switch node.Value {
case "read-all":
return new(repo_model.MakeActionsTokenPermissions(perm.AccessModeRead))
case "write-all":
return new(repo_model.MakeActionsTokenPermissions(perm.AccessModeWrite))
default:
// Explicit but unrecognized scalar: return all-none permissions.
return new(repo_model.MakeActionsTokenPermissions(perm.AccessModeNone))
}
}
// Handle mapping: individual permission scopes
if node.Kind == yaml.MappingNode {
result := repo_model.MakeActionsTokenPermissions(perm.AccessModeNone)
// Collect all scopes into a map first to handle priority
scopes := make(map[string]perm.AccessMode)
for i := 0; i < len(node.Content); i += 2 {
if i+1 >= len(node.Content) {
break
}
keyNode := node.Content[i]
valueNode := node.Content[i+1]
if keyNode.Kind != yaml.ScalarNode || valueNode.Kind != yaml.ScalarNode {
continue
}
scopes[keyNode.Value] = parseAccessMode(valueNode.Value)
}
// 1. Apply 'contents' first (lower priority)
if mode, ok := scopes["contents"]; ok {
result.UnitAccessModes[unit.TypeCode] = mode
result.UnitAccessModes[unit.TypeReleases] = mode
}
// 2. Apply all other scopes (overwrites contents if specified)
for scope, mode := range scopes {
switch scope {
case "contents":
// already handled
case "code":
result.UnitAccessModes[unit.TypeCode] = mode
case "issues":
result.UnitAccessModes[unit.TypeIssues] = mode
case "pull-requests":
result.UnitAccessModes[unit.TypePullRequests] = mode
case "packages":
result.UnitAccessModes[unit.TypePackages] = mode
case "actions":
result.UnitAccessModes[unit.TypeActions] = mode
case "wiki":
result.UnitAccessModes[unit.TypeWiki] = mode
case "releases":
result.UnitAccessModes[unit.TypeReleases] = mode
case "projects":
result.UnitAccessModes[unit.TypeProjects] = mode
// Scopes github supports but gitea does not, see url for details
// https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-syntax
case "artifact-metadata", "attestations", "checks", "deployments",
"id-token", "models", "discussions", "pages", "security-events", "statuses":
// not supported
default:
setting.PanicInDevOrTesting("Unrecognized permission scope: %s", scope)
}
}
return &result
}
return nil
}
// parseAccessMode converts a string access level to perm.AccessMode
func parseAccessMode(s string) perm.AccessMode {
switch s {
case "write":
return perm.AccessModeWrite
case "read":
return perm.AccessModeRead
default:
return perm.AccessModeNone
}
}