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Files
homelab-deploy/internal/builder/config.go
Torjus Håkestad c52e88ca7e fix: add validation for config and reply subjects
Address medium severity security issues:

- Validate repo names in config only allow alphanumeric, dash, underscore
  (prevents NATS subject injection via dots or wildcards)
- Validate repo URLs must start with git+https://, git+ssh://, or git+file://
- Validate ReplyTo field must start with "build.responses." to prevent
  publishing responses to arbitrary NATS subjects

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2026-02-10 22:09:51 +01:00

97 lines
2.3 KiB
Go

package builder
import (
"fmt"
"os"
"regexp"
"strings"
"gopkg.in/yaml.v3"
)
// repoNameRegex validates repository names for safe use in NATS subjects.
// Only allows alphanumeric, dashes, and underscores (no dots or wildcards).
var repoNameRegex = regexp.MustCompile(`^[a-zA-Z0-9_-]+$`)
// validURLPrefixes are the allowed prefixes for repository URLs.
var validURLPrefixes = []string{
"git+https://",
"git+ssh://",
"git+file://",
}
// RepoConfig holds configuration for a single repository.
type RepoConfig struct {
URL string `yaml:"url"`
DefaultBranch string `yaml:"default_branch"`
}
// Config holds the builder configuration.
type Config struct {
Repos map[string]RepoConfig `yaml:"repos"`
}
// LoadConfig loads configuration from a YAML file.
func LoadConfig(path string) (*Config, error) {
data, err := os.ReadFile(path)
if err != nil {
return nil, fmt.Errorf("failed to read config file: %w", err)
}
var cfg Config
if err := yaml.Unmarshal(data, &cfg); err != nil {
return nil, fmt.Errorf("failed to parse config file: %w", err)
}
if err := cfg.Validate(); err != nil {
return nil, err
}
return &cfg, nil
}
// Validate checks that the configuration is valid.
func (c *Config) Validate() error {
if len(c.Repos) == 0 {
return fmt.Errorf("no repos configured")
}
for name, repo := range c.Repos {
// Validate repo name for safe use in NATS subjects
if !repoNameRegex.MatchString(name) {
return fmt.Errorf("repo name %q contains invalid characters (only alphanumeric, dash, underscore allowed)", name)
}
if repo.URL == "" {
return fmt.Errorf("repo %q: url is required", name)
}
// Validate URL format
validURL := false
for _, prefix := range validURLPrefixes {
if strings.HasPrefix(repo.URL, prefix) {
validURL = true
break
}
}
if !validURL {
return fmt.Errorf("repo %q: url must start with git+https://, git+ssh://, or git+file://", name)
}
if repo.DefaultBranch == "" {
return fmt.Errorf("repo %q: default_branch is required", name)
}
}
return nil
}
// GetRepo returns the configuration for a repository, or an error if not found.
func (c *Config) GetRepo(name string) (*RepoConfig, error) {
repo, ok := c.Repos[name]
if !ok {
return nil, fmt.Errorf("repo %q not found in configuration", name)
}
return &repo, nil
}